A Performance Analysis of the ITU-T Draft H26L Video

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Chapter 5 A PERFORMANCE ANALYSIS OF MEERKAT This chapter compares the performance of progra

Chapter5A PERFORMANCE ANALYSIS OF MEERKATThis chapter compares the performance of programs running on both the Meerkat prototype and Meerkat simulator with those running on Intel’s Touchstone Delta[7]. These comparisons demonstrate that Meerkat is an effective multicomputer architecture when compared to Delta,a heavily used,commercially built multicomputer.Our tests prove that:(1)Meerkat can drive its interconnect at nine times the rate of the Delta,(2)the bisection bandwidth of a256-node Meerkat is three times higher than that of the same-sized Delta,and(3)Meerkat’s speedups exceed Delta’s up to the limit of Meerkat’s scaling range.Our simulated Meerkat,which can have up to256nodes,is calibrated to our prototype hardware,which has four nodes.The prototype cannot scale beyond its small number of nodes.The limited scalability of the prototype is not indicative of the architecture’s potential.Rather,it was a decision made to facilitate timely results from a one-person effort.In contrast to the prototype,the architecture can scale to hundreds of nodes.That is,the architecture permits designs that have many nodes and that are only slightly more complicated that our prototype.We introduce the differences between Meerkat and Delta in Section5.1.Section5.2dis-cusses the relationship between multicomputer interconnect performance and message size. Section5.3describes the message-passing primitives that we implemented for Meerkat. Section5.4gives insight into the implementation of these primitives.The interconnect’s performance under light and heavy loads is analyzed in Sections5.5and 5.6.Meerkat’s performance on two numerical applications is shown in Sections5.9and5.10.5.1IntroductionLike Meerkat,Delta is a multicomputer composed of RISC processors,local memory,and an interconnect that is used explicitly by application software.The two systems differ in2their interconnects:Delta employs a conventional mesh of2-D routers,while Meerkat uses sets of vertical and horizontal internode buses.There are other differences between Meerkat and Delta that complicate the comparison of the two interconnect architectures:The40MHz Intel i860processors in Delta are about twice as fast as the20MHz Motorola88100processors in Meerkat.Meerkat’s message-passing code is written in carefully crafted assembler,while Delta runs the NX/M operating system[6],written in C.The Meerkat internode interface copies to and from memory,whereas the Delta interface requires the processor to load and store each byte moved through the interface(i.e.,programmed I/O).The Delta test program runs in an address space separate from NX/M and thus incurs context-switching costs,while Meerkat’s test program runs in the same address space as the message-passing library.Some of these differences,however,offset others.For example,the slower Meerkat processors executing our small,message-passing library offset the effect of faster Delta processors executing the larger NX/M operating system.Despite these differences,there are conclusions we can draw from experiments com-paring the systems.We know that the Delta is an effective multicomputer.If we can show that Meerkat’s performance is better,we can conclude that Meerkat is also effective.5.2Message GranularityInterconnect bandwidth and latency are functions of message size.Message size itself is a function of the:(1)algorithm,(2)data layout,(3)number of nodes applied to the problem, and(4)problem size.In general,if the number of nodes increases while other parameters remain constant,the size of messages will decrease.Likewise,an increase in problem size often increases the message size.While a comprehensive discussion of message size exceeds the scope of this thesis,we provide the following examples as background for our subsequent performance discussion: The butterﬂy FFT algorithm using a cyclic layout generates messages that are3We speculate that operating system trafﬁc on Meerkat would be composed of both short control messages and page-sized messages to supportﬁle system and virtual memory trafﬁc.Process migration would generate messages in excess of64K bytes.Blocked iterative solution methods send messages that are proportional to the size of one edge of the block.A red/black successive over relaxation algorithm on a4096by 4096grid running on256nodes will use a block that is16by16.For double-precision numbers,each message will be1024bytes.5.3Message PassingAll benchmarks use a subset of Delta’s message-passing library,which we implemented on Meerkat.The subset contains the following primitives:Void csend(int type,const char buf,int size,int dest) Int irecv(type,char buf,int size)Void msgwait(int key)Csend sends a message of type type to node dest of length size whose data starts at address buf.Message delivery is reliable and in-order.Control does not leave csend until the message is delivered to the destination node,although it can be buffered by the receiving node until the application asks for it.If dest is,the message is broadcast to all nodes.Irecv tells the message-passing system that:(1)the application is ready to receive a message of type type in a buffer of length size bytes or less,and(2)that the buffer starts at address buf.A type of matches any received type.Irecv returns a key that can subsequently be passed to msgwait.Msgwait returns when the buffer associated with the passed key isﬁlled with a received message.If irecv is called with a typeﬁeld matching a message that has been received but not yet been delivered to the application, the message will be copied into the buffer supplied by irecv.Irecv checks for a message with a matching type.If one has arrived,it copies the message to the user buffer and returns a value that will tell a subsequent call to msgwait that the message has arrived.If not,it allocates a pending-receive record and puts this record,which contains the user’s buffer description and the expected message type,on a list of pending receive records.When the message arrives,it is delivered directly into the buffer supplied by irecv.In Meerkat,the key returned by irecv is zero if the message is waiting.Otherwise,it is a pointer to the newly allocated pending-receive record.Msgwait returns immediately4if it is passed a zero.If not,it spins,waiting for the passed pending-receive record to be marked "done"by the internode interrupt handler.5.4Chronology of Csend and Irecv Message PrimitivesFigure 5.1shows timelines with a simple csend and irecv/msgwait .A sending node is on the top timeline,and a receiving node on the bottom.The sender executes csend ,while the receiver executes an irecv followed by a msgwait .TIMEinterrupt routine returns Sender (csend)Receiver (irecv/msgwait)Cache flushPacketizeI-cache preloadArbitrationControl rendezvousData rendezvousReceiver sees internode interruptInterrupt overheadIrecvMsgwaitMessage transmissionMessage receptionreturns to applicationMsgwait returnsCsend Check arguments/save registersFigure 5.1:Simple Csend and Irecv/Msgwait TimelineThe steps of csend are:1.Argument checking :check arguments to csend ,test for broadcast,test for destina-tion node being equal to the sending node,determine routing (i.e.,1-bus vs.2-bus;if 1-bus,horizontal vs.vertical).2.Data cache ﬂush :instruct the data cache to write back to memory any dirty cache lines that hold data in the range of memory addresses to be sent.3.Message packetize :divide the message into one or more data packets and,in so doing,construct a control packet.4.Internode bus arbitration :acquire ownership of the required buses.55.Instruction cache preload:preload the sender-receiver rendezvous code in thesender’s instruction cache.This code can cause a bus timeout on the receiver if it does not execute certain groups of instructions quickly enough.Preloading the instruction cache makes the critical groups execute quickly.Preloading is done by executing critical code with parameter values that cause no internode activity.6.Control packet rendezvous:signal the receiver node,wait for it to enter a receptivestate,and begin to transmit the control packet.The receiver takes an interrupt when it is signalled.7.Data packet rendezvous:signal the receiver node,wait for it to enter a receptive state,and begin to transmit a portion of user-speciﬁed data.The receiver polls for signals from the sender and thus avoids the interrupt overhead.8.Data transfer:move data from the sending processor’s memory to the receiver’smemory.Each word moved requires one cycle.9.Miscellaneous processing:call subroutines,save/restore registers,return to caller,etc.Table5.1shows the execution cost of csend steps as a function of message size.Each pair relates the number of cycles for a given step followed by the percentage this step represents of the total time for csend.Table5.1:Number of Cycles and Percentage of Total Time Taken by Csend Step (Percentages Rounded to the Nearest Point)12832,7681+9.Miscellaneous overhead114/25%164/15%240/30%1,134/10%21/3%172/2%61/8%81/0%30/4%30/0%144/18%158/1%148/18%769/7%32/4%8,192/74%801/100%11,102/100%The table shows that,as message size increases,the percentage of time spent sending data through the interconnect(Step8)increases.Similarly,for all steps except Step8, as message size increases,the percentage of time spent decreases.For example,zero-byte messages spend11%of execution time in arbitration;thisﬁgure decreases toﬁve percent for1,024-byte messages,and to less than half a percent for32,768-byte messages.6Miscellaneous overheadﬁgures include time spent on argument checking and routing decisions.Table5.2shows the execution cost to a receiving node given four message sizes. The irecv row shows the cost of posting a receive,i.e.,of recording the user’s request for a message in advance of the message’s reception.The next row shows the cost of executing the interrupt subroutine that causes the rendezvous with the sending node,places data in the user’s buffer,etc.The‘interrupt overhead’line contains time spent by the processor:context-switching to the interrupt exception handler,decoding the interrupt, saving registers,acquiring a semaphore that guards against conﬂicting use of the network interface,and receiving the control packet.The time spent receiving a message overlaps with the sending node’s time for sending.Table5.2:Number of Cycles Taken by Message-Reception Step12832,768irecv(post a receive)116373Message reception105434Interrupt overhead13713464310,819Table5.2reveals several characteristics of the message-passing library.First,posting a receive requires a cacheﬂush in order to maintain consistency.The larger the buffer, the more cache state must be adjusted,and the longer the time will be to post the receive. However,the increase is sublinear;beyond a certain message size,the whole cache is ﬂushed.Theﬁrst line of the table shows:(1)182cycles toﬂush theﬁrst128bytes,or about 1.4cycles per byte,(2)75cycles toﬂush the next896bytes,or0.083cycles per byte,and (3)941cycles toﬂush the next31744bytes,or0.029cycles per byte.Second,the table shows that,for large messages reception itself,(i.e.,moving the data from the interconnect to the receiver’s memory)dominates execution time.The reception time goes from0.82cycles per byte for small messages to0.28for long messages.If there were no software overhead,thisﬁgure would be0.25cycles per byte(one cycle per word). Thus,for long messages,Meerkat’s message reception approaches the hardware transfer rate.Lastly,the interrupt overhead is fairly constant,rising slightly for the largest messages.7This rise of26cycles(160-134)for32,768-byte messages is due to cache effects:large messagesﬂush the whole cache,including variables used by the message-passing library. The26-cycle increase represents the time to reload these variables.5.5Bandwidth under Light LoadThis section reports the performance of Meerkat and Delta on a simple test that measures the ability of nodes to exchange data of varying sizes.The core of the program for this test appears in Figure5.2:light_load_test(char*buf,int size){double start,end,elapsed_time,bytes_per_second;int key;switch(mynode()){case0:start=time_in_seconds();key=irecv(0,buf,size);csend(0,buf,size,3,0);/*Send to node3*/msgwait(key);end=time_in_seconds();elapsed_time=end-start;bytes_per_second=2*(size/elapsed_time);printf("MB/sec for message of%d bytes=%7.3lf\n",size,bytes_per_second/1000000.0);break;case3:crecv(0,buf,size);csend(0,buf,size,0,0);/*Send to node0*/}}Figure5.2:Message-Passing Program to Test Meerkat under Light LoadThis test causes node zero to send a message of length size to node three.Node three waits for the message,which it sends to node zero.The total number of bytes sent is twice the message size.We measure the time interval from immediately prior to node zero’s transmission until immediately after node zero receives a reply from node three.We chose the node numbers(zero and three)so that the communication requires a two-bus connection.We execute the sequence above for message sizes ranging from four to256k bytes.Figure5.3shows the bandwidth achieved by a pair of nodes for both systems as a function of message size.We include in these graphs the bandwidth measured on the Intel Hypercube iPSC/2and iPSC/860[1].In this test the bandwidths reported by the Meerkat simulator and the hardware differed by about one percent.Therefore,the Meerkat curve8can be viewed both as a measurement of a real system and as a simulation result.Meerkat Delta iPSC/860 iPSC/2|10|||||||||100|||||||||1000|||||||||10000|||||||||100000|0|||||||||1|||||||||10|||||||||100Message size (bytes)B a n d w i d t h (M B /s e c o n d )Figure 5.3:Bandwidth as a Function of Message Size under Light Load The bandwidth of both Meerkat and Delta on small messages is limited by the ability of the nodes to inject messages into the network.The lower performance of Delta on small messages may be due to the extra work done in NX/M that is not done in the Meerkat message-passing library.Meerkat achieves 67MB/sec for 100,000-byte messages,while Delta’s bandwidth levels off at about 8MB/sec for 2,000-byte messages.Both Meerkat and Delta are limited on long messages by their different abilities to drive their interconnects.Meerkat’s internode bandwidth reaches 83percent of its peak rate of 80MB/sec.Delta reaches 10percent of its theoretical rate,which is also 80MB/sec [11].Delta’s ability to drive its interconnect in this test is limited by its network interface and the speed of the node processor.The network interface requires that the processor manipulate each byte sent through the interconnect.In the next section,we will see that Delta’s network can handle more trafﬁc than a single node can generate.While Meerkat’s maximum interconnect performance is seen at a message size that is longer than most applications will generate,its performance on shorter messages is still high.It may make sense,however,to reduce the per-message overhead by moving logic9from low-level software into hardware.This would push the solid curve in Figure5.3 higher and to the left.Chapter6discusses changes to the network interface that can reduce per-message overhead.5.6Bandwidth under Heavy LoadIn this experiment there are two groups of128nodes each,A and B,as shown in Figure5.4. Each node in group A sends a message to its partner in group B and waits for a reply.Each node in group B waits for a message from its partner in group A;it then sends a message back to its partner.The nodes of each group are physically contiguous in an8by16block, and the two groups are adjacent to form a16by16block of nodes.The distance between each node and its partner is eight.The total number of bytes moved between the groups is the product of the message size and the number of messages sent,which is256.We calculate the bandwidth by dividing the total number of bytes moved by the round triptime.ABFigure5.4:Pattern of Communication during Heavy Load Test Figure5.5shows both Meerkat and Delta with a nearly linear increase in bandwidth with increasing message size for messages of less than500bytes.As with the light interconnect load,this increase results from the amortization of aﬁxed processor overhead per message over longer messages.The Delta bandwidth reaches a maximum of280MB/sec with a message size of1000bytes.Meerkat peaks at750MB/sec at a message size of4000bytes.10Meerkat Delta|0|1000|2000|3000|4000|0|100|200|300|400|500|600|700|800 Message Size (Bytes)B a n d w i d t h (M B /s e c )Figure 5.5:256-Node System Bisection BandwidthDividing each of these bandwidths by the number of channels through which the data move,in this case 16,we ﬁnd that Meerkat’s buses are driven at an average of 46MB/sec.Delta’s channels at the midpoint are driven at 17MB/sec.Delta’s channels are composed of pairs of unidirectional links.Through separate tests,we determined that the maximum undirectional link speed is 11MB/sec.Thus,the 17MB/sec ﬁgure shows that our heavy-load test overlaps the use of these unidirectional links.The earlier plateau in Delta’s bandwidth is due to Delta’s higher ratio of processor to interconnect performance.That is,Meerkat’s slower processors need longer messages to saturate its faster interconnect.However,the level of the plateaus depends on interconnect performance rather than processor speed.5.7Per-Node BandwidthTo better understand what the results in the previous section mean for application perfor-mance,we consider the amount of internode bandwidth available to each node.We assume that the system is heavily loaded and that each node uses an equal amount of bandwidth.Figure 5.6shows system bisection bandwidth divided by the number of nodes.This graph is in units of double words (DW)(8bytes),as this is often the unit in which numerical applications programmers consider problem and message sizes.The per-node bandwidth is shown for several sizes of Meerkat and rger systems have lower per-node bandwidths because the bisection bandwidth increases with the square root of the number of nodes.16-Node Meerkat 64-Node Meerkat 144-Node Meerkat 256-Node Meerkat 16-Node Delta256-Node Delta|0|250|500|750|1000|0.0|0.5|1.0|1.5Message Size (Double-Words)M e g a D W /S e c P e r N o d eFigure 5.6:Per Node BandwidthConsider this example:if an application running on a 144-node Meerkat has every node send 500-DW messages and does no computation,every node will sustain a transfer rate of 550,000DW/sec.All applications will spend some of their time computing,so these curves represent the upper bound on internode performance.These ﬁgures assume that nodes share the interconnect equally.The internode bandwidth seen by a single node can be much higher if other nodes make only light use of the interconnect.These curves show that Delta has a lower per-node bandwidth than Meerkat for the same reasons given in the prior two sections for lower bandwidth.These differences are mostly a function of implementation,not of architecture.However,the ease with which we were able to design and build a fast implementation is a result of Meerkat’s simplicity.5.8Application PerformanceIt is important for prospective parallel computer users to be able to anticipate how well their applications will run.A given parallel application may run well on some computers and poorly on others."Running well"is,of course,subjective.The deﬁnition we adopt in this section is that the processors execute application code for at least half of the overall execution time.This section characterizes the applications that are likely to run well on Meerkat.We deﬁne these applications in terms of the application’s computation and communication demands.Our goal is to give application developers enough information to decide what combinations of parallel applications,input data sizes,and Meerkat conﬁgurations will run well.The principal application characteristics that determine performance on Meerkat are: (1)the ratio of computation to communication,(2)message size,and(3)load balance.Theﬁrst characteristic,the comp/comm ratio,is the ratio of the instructions executed to the amount of data sent between nodes[10].For example,an application that executes one million double-precisionﬂoating point instructions on each of256processors,and which passes two million double words between nodes,has a comp/comm ratio of128.That is, each node will perform an average of128FP operations for each DW value it sends to another node.The second application characteristic of importance is the grain size,the size of the message the application uses to package internode data.As the grain size decreases,the time spent to process messages increases.This computational effort comes at the expense of application running time.Both of these characteristics are functions not only of the application,but also of the problem size,the number of nodes,and the details of how the application is implemented. Some algorithms,such as Cholesky factorization,use messages with sizes that are also a function of the input data.Other algorithms,e.g.,modiﬁed Gram-Schmidt with partial pivoting[12],have a comp/comm ratio that is a function of the input data.Estimating the ratio for these applications may be difﬁcult.Applications that have very high comp/comm ratios,e.g.,over a million to one,will perform well on almost any parallel computer.They spend almost all of their time comput-ing.Even if internode communication is expensive,they spend little time communicating. These applications are perhaps best served by parallel computers with low-performance,inexpensive interconnects.Applications that have very low comp/comm ratios,e.g.,between zero and one,will perform poorly on any parallel computer.They will spend most the time communicating and little time computing,leaving processors idle most of the time.These applications are probably best run on uniprocessors,where no internode communication is necessary.Between these extremes are applications that will run well on some systems but not on others.To gauge whether they will run well,i.e.,with high processor utilization,we consider the comp/comm ratio of the parallel computer.This is the ratio of the rate at which each node can execute instructions to the rate at which each node can transmit data. For example,a system with processors that can sustain10MFLOPS and in which each processor can transmit data at1millionﬂoating point values per second(while the other processors are doing the same)has a comp/comm ratio of10.Comparing the system’s ratio with the application’s allows us to determine whether the application will run well.If the system’s ratio is much lower than the application’s,we expect that the application will spend most of its time computing,little time waiting for internode data,and will run well.On the other hand,if the system’s ratio is much higher than the application’s,the application will spend most of its time waiting for communication phases to complete,and it will run poorly.Processors can also have low utilization if the computational load is not balanced.Thus, it is not good enough to have an application comp/comm ratio that is higher than the system’s. Many regular problems,such as FFT and SOR(described in the next two sections),present the same computational load to each node,regardless of the input data.Other algorithms, however,require variable amounts of computation.In Cholesky factorization[5,2],each processor is assigned aﬁxed portion of the matrix on which to operate.However,the number of operations performed on each portion is a function of the input data.Some processors may be idle,while others are busy.This load imbalance can be lessened by choosing a small block size.However,this decreases grain size and thus communication efﬁciency.There is a tension between making the block size small,to increase load balance, and making it large,to amortize theﬁxed message cost overhead.Meerkat’s comp/comm ratio is a function of message size and system size,as shown in Figure5.7.These curves were generated by dividing the nominal node execution rate(10 MFLOPS)by the per-node internode bandwidth(shown in Figure5.6).Consider a sample use of these curves.Assume that we want to know how small we256-Node Delta 256-Node Meerkat 144-Node Meerkat 64-Node Meerkat 16-Node Meerkat|||||||10|||||||||100|||||||||1000||||||10|||||||||100|||||||||1000|Message Size (Double Words)F L O P /D o u b l e -W o r d M o v e dFigure 5.7:Meerkat and Delta Computation/Communication Ratiocan make the input to an FFT algorithm on a 64-node Meerkat without poor processor utilization.The input size is measured in points;each point requires two double words.Because FFT divides the input data evenly across all of the nodes,and communicates this data between pairs of nodes at each communication step,the input size will be 32times the message size:J.P.Singh gives large-message ratios for several commercial multicomputers[10].These are reproduced in Table5.3,along with the values we measured on Delta and Meerkat. While we have listed ourﬁgures with Singh’s,we note that his were derived from simple calculations,while ours started with measured bisection bandwidths.This makes the two sets of numbers not perfectly comparable,but we feel they are close enough to warrant rough comparison.Table5.3:Large-Message Computation/Communication Ratios For Meerkat and Several Commercial Systems(partly from J.P.Singh)Comp/Comm Ratio5811162050100144Singh also gives the computation and communication functions for several represen-tative numerical algorithms as a function of input and system sizes.These are shown in Table5.4;is the problem input size,is the number of processors.Table5.4:Computation/Communication Ratios For Several Numerical Algorithms (From J.P.Singh)CommunicationLU DecompositionFFTBy comparing an algorithm’s comp/comm ratio with the system’s ratio,we can estimate how a particular problem and input size will run on a particular system.5.9Performance of 1-D FFTFFT,a common computational problem for large parallel systems,often has poor perfor-mance,although speedup would be linear if communication cost was zero.Figure 5.8shows Meerkat’s and Delta’s speedup achieved on a one-dimensional FFT [3]as a function of the number of nodes applied to the problem.Curves for two input sizes are shown:4096and 32768points.The input points are evenly spread amongst the nodes;each point consists of a pair double precision ﬂoating point values.Ideal Speedup Meerkat 32kMeerkat 4k Delta 32kDelta 4k|0|50|100|150|200|250|0|20|40|60|80|100|120|140 Number of NodesS p e e d u pFigure 5.8:Speedup of 4k-and 32k-Point FFTThe total amount of computation is a function of the problem size,not the number of processors applied to the problem.Withpoints andprocessors,there aresteps.Each step takes time proportional to ,and the last steps require communication.Thus,as the number of processors increases,and the total running time decreases,theeffect of communication may dominate.Also,while the number of messages each node sends per step is constant,the message size is proportional to。

电路理论存在互易性与对称性时二端口网络的参数特征

参考文献
1 邱光源. 电路. 北京: 高等教育出版社, 1990 2 姚仲兴. 电路分析导论. 杭州: 浙江大学出版社, 1989 3 王蔼. 基本电路理论. 上海: 上海交通大学出版社, 1986
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山东建材学院学报
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之泥浆沉淀, 因此成孔后孔底沉渣过多, 孔底清渣工作费时费力。所以, 机具损耗大, 成孔速度慢, 成孔费用高。扩底灌注桩与钻孔灌注桩比较, 成孔速度快, 成桩质量高, 成桩费用低。
数的 Z 12= Z 21; T 参数的 A D - BC= 1及 H 参数的 H 21= - H 12。因此对线性非时变、零状态、不含源的
二端口网络, 其 Y 参数中只有 3个参数是独立的, 求解这类二端口参数时, 只需求解 3个参数就可以了。 1. 2 二端口具有对称性时的特征
在二端口网络具有互易性的基础上, 若具有对
W ang Yan, L i Yan
(D eper tm en t o f In fo rm a tion and C on tro l Engee r ing, S IBM , Jinan 250022)
Ab strac t T he re la tion ship o f th e fou r vo ltag e s and cu rren ts in tw o -po re ne tw o rks can be described u sing six d iffe ren t k inds o f pa ram e te rs, and eve ry param e te r ha s fou r elem en ts respe ctive ly. If re cip roc ity and symm e try ex ist fo r pa ss iv e tw o-po r t ne tw o rks o f linea r tim e-inv a rian t under zero-in tial condition, the c ircu it pa ram e te rs w ill hav e som e im po r tan t char acter s. In th is paper, these cha rac te rs a re analy zed and discussed pa r ticu lar ly, then the sim p lified m e thod o f param eter s ca lcu la tio n is p resen ted.

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Stability directlyaffects a laboratory’s ability to delivertimekeeping and calibration services toits clients.The 5071B offers exceptional stabilityand is the first cesium standard tospecify its stability for averaging timeslonger than one day. The instrumenttakes into account environmentalconditions that can heavily influencea cesium standard’s long-term stabil-ity. Digital electronics continuouslymonitor and optimize the instrument’soperating parameters.Thus, the 5071B’s response to environ-mental conditions such as temperatureand humidity are virtually eliminated.The 5071B primary frequency standardmaintains its accuracy and stability,even in unstable environments.Satellite CommunicationsStable frequency generation is required to transmit and receive signals properly between ground terminals and com-munication satellites. Frequency flexibility is also needed to adjust for satellite-to-satellite carrier-frequency differences. The 5071B’s state-of-the-art technology produces offset and primary frequencies with the same guaranteed stability.For secure communications, precise timing synchroniza-tion ensures that encrypted data can be recovered quickly. Frequency-agile signals also require exact synchronization between transmitter and receiver during channel hops.The 5071B automates the synchronization to any external1PPS signal, greatly simplifying this aspect of satellite communications.The 5071B and GPSThe 5071B primary frequency standard can work very well with a GPS timing receiver to produce and maintain highly accurate time and frequency.The GPS system provides accurate time, frequency, and location information worldwide by means of microwave radio broadcasts from a system of satellites. Timing accuracy for the GPS system is based, in large part, on the accuracy and stability of a number of 5071B primary frequency standards. These standards are maintained by the GPS system, the US Naval Observatory, and various timing laboratories around the world that contribute to UTC, the world time scale. Because of their accurate time reference, GPS signals pro-cessed by a good GPS timing receiver can provide highly accurate time and frequency outputs. However, since GPS receivers rely on very low level microwave signals from the satellites, they sometimes lose accuracy because of interfer-ing signals, local antenna problems, or bad satellite data.In spite of these problems, a GPS timing receiver can be an excellent backup and reference to a local 5071B primary frequency standard. The GPS receiver provides an indepen-dent reference that can be used to verify the accuracy of a caesium standard, or it can be used as a temporary backup should the cesium standard need repair. The local 5071B standard has better stability, better output signal quality, and is not perturbed by interfering signals, intermittent signal loss, or bad satellite data.With these characteristics, the synergy created by combin-ing a good quality GPS timing receiver and a 5071B primary frequency standard can produce a highly robust, inexpensive, and redundant frequency and time system. Exceptional AccuracyThe intrinsic accuracy of the improved cesium beam tube (CBT) assures that any high performance 5071B will power up to within ±5.0 x 10–13 of the accepted standard for frequency. This is achieved under full environmental conditions in 30 minutes or less, and without the need for any adjustments or alignments.Unsurpassed StabilityThe 5071B high-performance cesium beam tube guarantees stability to be better than 1.0 x 10–14 for averaging times of five days or greater. The 5071B is the first cesium standard to specify stability for averaging times longer than 1.0 x 105 seconds (approximately one day).The 5071B is also the first cesium standard to specify and guarantee a flicker floor. Flicker floor is the point at which the standard’s stability (σy (2, τ)) does not change with longer averaging. The high performance 5071B flicker floor is guar-anteed to be 1.0 x 10–14 or better. Long-term measurements at the National Institute of Standards and Technology (NIST) show that the flicker floor is typically better than 5.0 x 10–15. Unstable environments are normal for many cesium stan-dard applications. The 5071B features a number of micropro-cessor controlled servo loops which allow it to virtually ignore changes in temperature, humidity, and magnetic fields.The 5071B delivers exceptional performance over very long periods of time, greatly increasing the availability of critical time and frequency services. Actual measurements made at NIST have demonstrated that a 5071B with the high-perfor-mance CBT will drift no more than 5.0 x 10–14 over the entire life of the CBT.Traditional ReliabilityThe 5071B design is based off its predecessor, the 5071A, which has demonstrated an average mean time between failures (MTBF) of greater than 160,000 hours since its introduction in 1992. This data is based on actual field repair data. Backing up this reliability is a 10-year warranty on the standard long-life cesium beam tube and a 5-year warranty for the high performance tube.Complete repair and maintenance services are available at our repair center in Beverly, Massachusetts.Full Traceability to NISTMicrochip provides NIST traceability to the accuracy mea-surements made on every 5071B. Traceability to NIST is maintained through the NIST-supplied Time Measurement and Analysis System (TMAS). This service exceeds the re-quirements of MIL-STD-45662A and can be a valuable tool in demonstrating traceability to your customers.High-Performance Cesium Beam TubeThe 5071A high performance cesium beam tube is optimal for the most demanding operations. The high-performance tube offers a full-environment accuracy specification of±5.0 x 10–13 —two times better than the specification for the standard tube. Stability is also significantly improved. The high-performance tube reaches a flicker floor of 1.0 x 10–14 or better, and long-term measurements at NIST show that the flicker floor is typically better than 5.0 x 10–15. Integrated Systems and Remote OperationToday, cesium standards are often integrated into telecom-munication, satellite communication, or navigation systems as master clocks. To accommodate these environments, the 5071A provides complete remote control and monitoring capabilities. Instrument functions and parameters can be interrogated programmatically.Communication is accomplished using the standard com-mands for programmable instruments (SCPI) language and a dedicated RS-232C port. Also, a rear panel logic output can be programmed to signal when user-defined abnormal condi-tions exist.For uninterruptible system service, an internal battery provides 45 minutes of backup in case of AC power failure. Thus, the 5071A can be managed easily even in the most remote locations.Straightforward OperationInternal microprocessor control makes start-up and opera-tion of the 5071A extremely simple. Once connected to an AC or DC power source, the 5071A automatically powers up to its full accuracy specifications. No adjustments or alignments are necessary during power-up or operation for the life of the cesium tube.An intuitive menu structure is accessible using the front panel LCD display and keypad. These menus—Instrument State, Clock Control, Instrument Configuration, Event Log, Frequen-cy Offset and Utilities—logically report status and facilitate control of the instrument. These functions are described as follows.Instrument StateOverall status is displayed, including any warnings in effect. Key instrument parameters such as C-field current, electron multiplier voltage, ion pump current, and cesium beam tube oven voltage are available. You can initiate a hard copy report of this data on your printer with the push of a button. Clock ControlSet the time and date, schedule leapseconds, adjust the epoch time (in 50 ns steps), and automatically synchronize the 1PPS signal to within 50 ns of an external pulse using this menu.Instrument ConfigurationSet the instrument mode (normal or standby) and assign frequencies (5 MHz or 10 MHz) to the two independently programmable output ports; configure the RS-232C data port. Event LogSignificant internal events (power source changes, hardware failures, warning conditions) are automatically recorded with the time and date of their occurrence. A single keystroke produces a hard copy on your printer for your records. Frequency Offset (Settability)Output frequencies may be offset by as much as 1.0 x 10–9 in steps of approximately 6.3 x 10–15. All product stability and output specifications apply to the offset frequency. UtilitiesThe firmware revision level and cesium beam tube identifica-tion information can be displayed.Accuracy and Long-term Stability11Lifetime accuracy (high performance CBT only) after a minimum two-month warm-up. Change no more than 5.0 × 10–14 for the life of the CBT.Specificationsfront panel or by remote control.The Microchip name and logo and the Microchip logo are registered trademarks of Microchip Technology Incorporated in the U.S.A. and other countries. All other trademarks mentioned herein are property of their respective companies. © 2023, Microchip Technology Incorporated and its subsidiaries. All Rights Reserved. 8/23DS00005002CRemote System Interface and Control RS-232-C (DTE configuration)Complete remote control and interrogation of all instrument。

Highlights

BETTER COMMUNICATION ｜ GREATER VALUEHIGHLIGHTS ｜China-Germany working group on standardization strategyholds virtual meetingTian Shihong, Vice-Minister of SAMR and Administrator of SAC, attended the video conference of the China-Germany Working Group on Standardization Strategy taking place on March 1, 2021.The German participants include Ole Janssen, Deputy Director General of Innovation and T echnology Policy, Federal Ministry for Economic Affairs and Energy (BMWi), Christoph Winterhalter, Chairman of the Executive Board of DIN, as well as Michael T eigeler, Managing Director of DKE.The two sides held in-depth discussions on key topics including ISO Strategy 2030, IEC strategic plan, and machine- readable standards, and set the direction for future cooperation, for example expanding cooperation in artificial intelligence and circular economy. The working group will continue to serve as an important platform for the two sides to deepen cooperation in standardization strategies.China and UK exchange on international standards for sustainable development of small and medium-sized citiesThe Sub-Institute of Public Safety Standardization of CNIS undertakes “the pilot project on international standards for sustainable development of small and medium-sized cities” supported by China Prosperity Strategic Programme Fund (SPF) under the China-UK standardization cooperation framework. The project was officially launched in October 2020 and was expected to be completed by the end of 2021. A series of international standards on urban sustainable development have been implemented in four pilot cities in China.BSI project managers and evaluation specialists visited CNIS on April 1. The two sides exchanged views on issues of common interests such as project arrangement, latest progress, and expectations. Project leader Dr. Yang Feng introduced the advance of the pilot project. The project group successfully organized a number of China-UK working meetings online, despite the influence of COVID-19.The two sides agreed to enhance communication and cooperation on sustainable development and discussed the plan to encourage more Chinese cities to implement relevant international standards.Chinese version of renewable energy related IEC standard publishedProviding quality assurance in distance learning during pandemicThe Chinese version of IEC/TS 62257-9-8: 2020, Renewable energy and hybrid systems for rural electrification—Part 9-8: Integrated systems—Requirements for stand-alone renewable energy products with power ratings less than or equal to 350 W , was officially published on March 23, 2021.It is the second Chinese version of the IEC standards on renewable energy, following the Chinese version of IEC/TS 62257-9-5: 2018, which was published in October 2019.The standard defines the fundamental requirements in the aspects such as quality, durability and advertising authenticity of stand-alone renewable energy products.It enables Chinese enterprises to make products in conformity with international standards in a faster and better way, maintain a stable annual market scale of international stand-alone renewable energy products for USD 1.75 billion, and safeguard the rights of 420 million consumers across the globe, contributing to the realization of UN Sustainable Development Goals.The two standards will help further promote the application of IEC standards in China, improve the quality of Chinese products, and facilitate their access to global markets.ISO published a new standard on distance learning onApril 20, making up for the lack of guidance in the area.Experts from the Sub-Institute of Service Standardizationof CNIS served as the convenor and project leader ofcorresponding working group, contributing greatly to theinternational guidance that ensures agreed levels of qualityand transparency of distance learning.Due to the influence of COVID-19, more than 1.6 billionpeople have to receive education through online classes,according to the data from UNESCO, the UN culturalorganization. ISO 29994:2021, Education and learning services— Requirements for distance learning , creates a globally agreedmodel of distance learning, and provides a solution to thesurging demand for distance learning during the pandemic.Expanding use of IoT-based FintechA major step forward in compliance managementChina’s Wuxi IoT Research Institute has begun toexplore the application of Internet of Things (IoT) in thefinancial sector since 2012. It started the research onIoT and sensor network (SN) technologies that supportchattel asset monitoring and tracking in February 2017,and led the proposal for the first IoT-based Fintechstandard in the world in 2018.The standard ISO/IEC 30163, Internet of Things(IoT)—System requirements of IoT and sensor networktechnology-based integrated platform for chattel assetmonitoring , was recently published by IEC. It is applicable to the design and development of IoT/SN system for chattel asset monitoring supporting financial services.While developing standards, Wuxi IoT Research Institute has taken the lead in the application of IoT theory in the financial sector, helping financial institutions manage risks and manufacturers (esp. small and medium-sized enterprises) resolve financing difficulties.ISO 37301:2021, Compliance management systems—Requirements with guidance for use , officially published on April 13, is the first international standard developed by ISO/TC 309 (governance of organizations) since its inception in 2016.This document specifies requirements and provides guidelines for establishing, implementing, maintaining and improving a compliance management system within an organization. It is applicable to all types of organizations regardless of their size and nature.The standard was developed by the working group on compliance management systems (ISO/TC 309/WG4). Its convenor is Martin Tolar from Australia, co-convenor is undertaken by Wang Yiyi, head of Sub-Institute of Standardization Theory and Strategy, CNIS, and Wang Gengjie, assistant research fellow from CNIS serves as IS, mirroring ISO/TC 309, organized many domestic experts to participate in the development of ISO 37301.HIGHLIGHTS ｜BETTER COMMUNICATION ｜ GREATER VALUEBreakthrough in blockchain technology applied in e-invoice businessIndustrial Internet clearly definedIEEE Standards Association recently published the first international standard on e-invoice business using blockchain technology. The standard was completed with the leading effort of Shenzhen Taxation Bureau and T encent, a leading internet company founded in Shenzhen, China.IEEE 2142.1-2021, Recommended Practice for E-Invoice Business Using Blockchain Technology , describes the blockchain-based application reference architecture of e-invoice business, including roles of participants, typical business scenarios, platform frameworks, and security requirements.Tencent has been exploring the applications of blockchain technology since 2015 and has expanded its use in e-invoicing, supply chain finance, digital protection, product traceability and anti-counterfeiting, etc. The first e-invoice using blockchain technology in China was generated in Shenzhen in August 2018. T encent led the proposal of IEEE 2142.1 in May 2019.The document provides a foundation for the blockchain-based implementation solutions of e-invoice business, which will help optimize user experience and business efficiency.The International T elecommunication Union Bureauof Standardization (ITU-T) recently approved the draftITU-T Y.2623, Requirements and framework of IndustrialInternet networking based on future packet-based networkevolution , at the plenary session of the 13th StudyGroup (future network and cloud). China Academyof Information and Communication Technology(CAICT) led the development of the first internationalstandard in the field of industrial internet network,the key to transformation and upgrading of the globalmanufacturing industry.CAICT proposed the standard project in the 22ndQuestion Group “Upcoming network technologies for IMT-2020 & Future Networks” in June 2019. ITU-T Y.2623 clearly defines industrial internet for the first time as well as industrial internet network framework. It specifies requirementsfor general networking technologies and main functional parts for the interconnectivity of networks and data.。

2008 考研英语阅读真题Text 1(英语二)

2008 Text 1（英语⼆）处于压⼒下的⼥性While still catching up to men in some spheres of , women appear to be way ahead in at least one undesirable category."Women are particularly susceptible to developing depression and in response to stress compared to men, " according to Dr. Yehuda, chief psychiatrist at New York's Veteran's Administration Hospital.Studies of both animals and humans have shown that somehow affect the , causing females under stress to produce more of the trigger chemicals than do males under the same conditions.In several of the studies, when stressed-out female rats had their ovaries (the female reproductive organs) removed, their chemical responses became those of the males.Adding to a woman's increased dose of stress chemicals, are her increased "opportunities" for stress."It's not necessarily that women don't cope as well.It's just that they have so much more to cope with, " says Dr. Yehuda."Their capacity for tolerating stress may be even greater than men's, " she observes, "it's just that they're dealing with so many more things that they become worn out from it more visibly and sooner. "modern life 尽管⼥性在当代⽣活的许多领域仍在追赶男性，但⾄少在⼀个令⼈避之不及的领域遥遥领先。

the unit of analysis -回复

the unit of analysis -回复"the unit of analysis"单元分析（The Unit of Analysis）是研究设计和方法学领域中一个重要的概念，涉及到研究中所关注的基本单位或对象。

在社会科学和其他学科的研究中，研究者必须决定将注意力集中在什么样的单元上，以便深入理解研究问题并得出有意义的结论。

单元分析是一个策略性的决定，必须依据研究问题和研究目的来进行选择。

不同的单元可能包括个人、群体、组织、社区、国家等等。

选择合适的单元分析对于研究的可靠性和有效性至关重要，因为它直接影响着研究的结果和结论的推广性。

在进行单元分析时，研究者需要从以下几个方面考虑：1. 研究问题和目的：研究问题将决定研究者关注的范围和定位。

例如，如果研究问题是关于社区内的民主参与水平，那么社区可能是一个适合的单元，而不是个体或组织。

2. 理论框架：理论框架提供了对研究对象的理解和解释，帮助研究者确定适当的单元。

研究者需要考虑他们选择的理论是否与研究问题一致，并提供必要的解释和分析。

3. 数据收集和分析方法：研究者需要考虑如何收集和分析与所选单元相关的数据。

不同的单元可能需要不同的数据收集方法和分析技术。

例如，如果研究对象是个人，问卷调查可能是一个适当的数据收集方法；而如果研究对象是组织，采访和观察可能更为合适。

4. 外部有效性和推广性：选择合适的单元分析对于将研究结果推广到更广泛的领域至关重要。

研究者需要考虑所选单元分析的外部有效性，即是否能够适用于其他情境和人群。

一旦研究者明确了他们所关注的单元分析，他们可以按照以下步骤进行研究：1. 确定研究问题和目的：明确研究问题，并将其与研究目的和假设相匹配。

2. 研究领域和文献回顾：了解研究领域的现状和前沿，回顾相关文献，并了解以前的研究所选择的单元分析。

3. 确定适当的单元分析：根据研究问题、目的和理论框架，选择适当的单元分析。

国际电联会议文件常用英语词汇

国际电联会议文件常用英语词汇aa single itu-wide website for planning国际电联规划专用网址c-01/20aap（alternative approval procedure）替换批准程序，非传统批准程序itu-t, itu-rabusive registration恶意注册acceptance of the convention接受《公约》accepted meanings公认含义c-00/2access使用（权），接入（权）c-01/14accession to the convention加入《公约》account record会计账册，会计记录c-00/21accounting会计（工作），结算（工作）accounting document会计凭证c-01/13accounting procedure会计（结算）程序（方法）c-01/13accounting rate结算价c-00/35accounts payable应付账目c-01/54accrued paid annual leave积存带薪年假action plan行动计划c-00/32actual itu《国际电联情况通报》actual performance实际执行情况c-03/02addendum补遗additional appropriation追加拨款additional fee附加收费卫星网络申报additional plenipotentiary conference 增开的全权代表大会c-01/41additional session增开会议c-00/6additional terms of reference governing external audit 有关外部审计的附加权限c-00/16addressing寻址，编址c-00/3ad-hoc group特设组c-01/28administrations主管部门administrative and general support services行政管理和一般支持服务c-01/21administrative committee on coordination (acc)（联合国）行政协调委员会c-00/23administrative due diligence行政尽职调查c-01/28admission to a conference接纳出席一大会advance payments by clients客户预付款c-01/13advancement of women提高妇女地位res.1187 (council)advantage of synergies协同优势c-01/14advertise （ a post ）公布（职位空缺）advisory capacity顾问身份c-01/41advisory group顾问组c-00/12advisory panel专家组顾问africa telecom youth forum非洲电信展青年论坛c-01/17agenda item议项（第x项议程）align the operational planning cycle with the biennial budget 使运作规划周期与双年度预算协调一致c-01/20all groups of society that are not fully benefitting from the availability of icts所有未能充分受益于信息通信技术的社会群体c-01/17allocation（频率）划分；分配（资源、文件）allocation of documents文件分配c-01/66allocation of expenditure and income 支出和收入的分配c-01/13allocations拨款c-00/21allotment（频率）分配allowable educational expenses可报销的教育费用c-01/18alternate calling procedure迂回呼叫程序（方式）alternate representative候补代表staff regulationsamend修正c-00/8amendment修正（案、条款、文字）america connectivity agenda美洲国家互连议程pp-02amount due应付金额amount of data storage capacity数据存储的容量c-01/2...amount would need to be found还有...的资金缺口an integration of voice and data networks话音和数据网络的结合c-01/14annex: 1附件：1件announcement宣布(所选会费单位/等级)c-03/02annual amounts of mobility and hardship allowance 调动和艰苦条件津贴年度金额c-00/8annual gross salaries年薪总额c-00/8annual salary scale年薪表c-00/8appellate body上诉受理机构c-00/9appendix/annex/attachment附录/附件/后附资料appointed official委任官员c-00/8appointed staff委任职员c-00/8antenna pattern天线方向图c04/doc/02， p.7appointment and promotions board 任命和晋升委员会c-03/61letter of appointment任用书c-01/22appointments/personal promotions 任命/人员晋升c-01/div/5apportioning ratios分摊比例c-01/54apportionment of revenues收入分摊c-00/1appraisal system鉴定制度c-01/22approval of the convention加入《公约》approve批准（决议）c-00/8apt (asia-pacific telecommunity)亚太电信组织architecture架构；体系结构c-01/14area office地区办事处"arm's-length" organization相对独立的机构c-03/35arrears and special arrears accounts欠款和欠款专账c-00/20article 1第 1 条asp (application service provider)应用服务提供商assembly全会assessed contribution应摊会费assessment (lowest/highest assessment) 应摊会费(最低/高应摊会费) assessment rates薪金税率c-00/84assessment scale会费分摊比额；薪金税率表assignment（频率）指配assignments指派；指派任务（《人事规则》）c-03/22assignment grant派任津贴assistant vice-president助理副总裁c-01/14associate member (of a sector)部门准成员c-00/1atm end system addresses (aesas) atm末端系统地址c-01/21attachment附文 (在annex中出现时)c-03/add/002attributed cost应计成本attribution of cost成本分摊c-03/28atu(african telecommunication union) 非洲电信联盟audited accounts审定账目authentication across borders跨国界鉴权c-00/2authentication measures鉴权措施c-00/2authorized授权/核准authorized representative受权代表pp-02available financial resources可利用的资金c-00/32avoid trivializing the issue (of gender)避免拘泥于（性别方面）的枝节问题c-00/94awareness campaign宣传活动c-01/13bbackground information背景资料/情况c-01/32backlog积压c-01/130base/floor salary scale基薪/底薪表c-00/8basic salary基本薪金constitutionbasic telecommunications agreement (wto) 基础电信协定c-01/38bdt (telecommunication development bureau)电信发展局be relevant in the fast changing world在迅速变化的世界中发挥应有的作用bearing in mind铭记（在决议、决定中的译法）(one month) before the opening of the conference 距大会开幕一个月以前general rulesbelow-the-line commitments特别预算承付款项c-03/3below-the-line liabilities特别预算负债benevolent funds福利基金c-00/21board of telecom电信展览部董事会boarding costs寄宿费c-01/18the body of the report报告的正文部分c-03/3br (radiocommunication bureau)无线电通信局brain-drain人才流失c-01/14breakdown of planned expenditure 计划支出的细分c-01/32bridging the digital divide弥合数字鸿沟bridge the gender divide缩小性别差距c-01/17broad banding宽幅薪金段broadband wireless access宽带无线接入c-01/38budget allocation预算拨款（分配）budget control committee预算控制委员会c-01/41budget submission预算申请c-03/add/002budgeted vacant post预算内空缺职位c-00/35building maintenance fund (bmf) 办公楼维护基金c-01/div/5buildings replacement value办公楼重置价值bureau (wsis-prepcom)(信息社会世界峰会政府间筹委会)主席团business plan业务计划，经营计划c-00/97ccancellation of network取消网络c04/doc/02， p10candidature (application for a post; everything submitted for this purpose)候选人（资料）；候选人资格capacity building能力建设career ladder职业阶梯career management officer职业管理官员c-01/22case study案例研究c-00/3cash compensation for overtime加班现金补偿cat (computer-aided translation)计算机辅助翻译ccaq(consultative committee on administrative questions)行政问题咨询委员会cctld国家码顶级域名res.102ccu （corporate communications unit ）国际电联宣传处c-01/36cec (coordination, external relations and communication units)协调、对外关系和宣传处c-01/36central europe and cis中欧和独联体centralized services集中服务c-03/2centres of excellence高级培训中心c-00/35ceo (chief executive officer)首席执行官certification authorities认证机构c-00/2chapter vi第六章（罗马数字用汉语代替）charge schedule收费表卫星申报checklist（核对）清单c-01/14chief administrative officer首席行政官c-00/16chief of fi dept.财务部主任cis region unit独联体区域处c-01/17citel (inter-american telecommunication conference) 美洲国家电信大会civil society民间团体c-01/126classification review board定级评审委员会c-03/61class of contribution会费等级c-00/1collective letter集体函c-00/12colloquium讨论会commentary评注c-00/9commitment分包合同（在承包工程的情况下）commitments承诺，承担义务(in finance) commitments承付款项c-03/3committee on budget预算委员会c-00/9committee on finance and administration财务和行政委员会c-00/9common proposal共同提案pp-02common provisions共同条款c-00/2common services department公共服务部c-00/35communauté financière africaine franc countries (cfa) (14个)使用法郎的非洲金融共同体国家c-01/18communication officer宣传联络官community connectivity indicators社区连通性指标pp-02comparator country for uncs联合国共同制度参照国pp-02compensating measure补偿措施c-00/46competent authority主管当局（机构）pp-02competent conference有权的大会pp-02complete overhaul大修c-01/13complete replacement of the fa?ade 全部更换外墙c-01/13compromise折衷pp-02/245computer and network division计算机和网络处c-01/2conditions of employment就业条件conventionconditions of service服务条件conferences department大会部c-00/35congé annuel年假connectivity连通（性）；互连consider审议，考虑consolidated budget汇总预算conventionconsolidated statements综合报表constitution of itu国际电联《组织法》c-00/9consultation征询，咨询，协商，磋商，会商contractual services承包服务c-01/2contribute to union expenditure 摊付国际电联支出的会费pp-02contribution文稿c-00/12contribution会费，捐款contribution (pension fund)缴纳金额conventioncontributory share会费份额contributory share for defraying union expenses摊付国际电联费用的会费份额c-00/6coordination arc协调弧c04/doc/02， p8the united nations shall be exempted from all contributions to defraying the expenditure of itu conferences and meetings in which it participates应免除联合国为摊付所参加的国际电联大会和会议的开支而缴纳的所有会费res. 925 (council)the council may exempt certain international organizations from any share in defraying the expenses of itu administrative conferences and meetins of the icc理事会可以免除某些国际组织摊付国际电联行政大会和国际咨询委员会会议的开支res. 925 (council)contributory unit会费单位convention of itu国际电联《公约》c-00/9convention on the privileges and immunities of the specialized agencies专门机构特权和豁免公约res. 1004 (council)coordination committee (coco)协调委员会corporate communication unit国际电联宣传处correspondence group信函通信组c-01/28corrigendum勘误(identifiable, auditable, prospective and retrospective) cost 可鉴别的、可审计的、预期和追溯）成本c-03/28cost accounting system成本核算体系c-03/28cost allocation drivers成本分配驱动因素c-01/54cost analysis activities成本分析活动c-01/2cost center出账项目，走账项目pp-02cost-effective低成本、高效益，成本效益好c-01/14cost effectiveness成本效益状况cost-oriented以成本为基础的，根据成本cost recovery成本回收cost reduction program费用削减计划c-03/add/006council 98 (c-98)理事会1998年会议council for trade in services of the world trade organization 世界贸易组织服务贸易理事会c-00/9council oversight group (cog)理事会监督组c-03/86council working group on itu reform(wgr)理事会国际电联改革工作组c-00/35councillor理事councillor's mission costs (budget)理事补贴c-03/add/002contribution units to defray the expenses of the union摊付国际电联费用的会费countries that apply calling-party-pays采用主叫方付费的国家c-01/12control objectives for information and related technology (cobit)信息及相关技术控制目标c-03/63cost-of-living allowances生活费津贴council members理事国course of action行动方针；行动方案covenant契约coverage level (of the reserve for debtors' accounts) 补偿比率c-03/53credentials committee证书审查委员会c-01/41creditor's account贷方账户cross-sectoral project teams跨部门项目小组c-01/28cs《组织法》currency areas货币区c-01/18current account往来账目，活期账户customary suppliers常用供应商c-01/13cut-off date截止日期c-01/54the cutting-cross nature of the ict信息通信技术的交叉连接特性c-03/94cv《公约》cybercafé网吧cyberspace网络空间，计算机时代c-01/12ddaily subsistence allowance每日生活津贴staff regulationsdebtor's account借方账户decent and productive work体面的和生产性的工作c-03/30decentralization(公共服务和支持服务方面的)预算分散管理c-03/02decides做出决定（在决定中，楷体）deferred life annuinties递延终身年金deficiency不足c04/doc/02， p.10defray支付c-00/1delegation of authority权力下放delink脱钩dependency受抚养人c-01/18dependency allowance抚养津贴undependency benefit抚养福利津贴staff regulationsdependency rate of post adjustment 有受抚养人的任职地点补贴调整数staff regulationsdependency rate of staff assessment 有受扶养人的薪金税率staff regulationsdependency rate salary有受扶养人的薪金staff regulationsdeposit of candidature候选人资料的交存depositary保存人；保存机构deregulation放松/解除管制desirable to宜应detachment临时调用development symposium for regulators监管机构发展报告会c-01/28difference (in terms of fund)资金的差额digital divide数字鸿沟digital divide initiatives关于数字鸿沟的举措/活动c-01/17digital opportunities task force (dot force)数字机遇任务组c-01/17digital sound broadcasting数字声音广播c-01/32director (of the bureaux)（各局）主任director of the swiss federal audit office (external auditor)(fr. directeur du contr?le fédéral des finances de la confédération suisse (vérificateur extérieur) (瑞士联邦审计署主任（外部审计员）(k. grüter)c-03/21direct-to-home television broadcasting 直接到户的电视广播c-01/38disbursement支付，支出discrepancy差异，不一致之处，出入c04/doc/02， p.10dispute resolution panel争议解决小组c-00/9dispute settlement body争议解决机构c-00/9document composition service文件排版服务室c-01/2documentation文件制作（提供），文件dominant operator主导运营商dotcom companies网络公司c-01/28draft agenda议程草案c-00/1draft decision决定草案c-00/20draft opinions意见草案c-00/3draft time management plan 时间管理计划草案c-01/66draw up invoices free of vat 开具免除增值税的发票due diligence procedure尽职调查程序duty station任职地c-00/21eeach reading每次审读（议案）eau (external affairs unit)对外事务处c-01/36e-business电子企业（商务）e-commerce电子商务economy of scale（scope）规模经济c-00/32ecosoc经济与社会理事会c-00/32editorial committee编辑委员会c-01/41edmg(electronic document management)电子文件管理室education grant教育补助金/补贴e-education电子教育efficiency committee增效委员会c-03/18efficiency measures增效措施c-01/2e-health电子卫生（医疗）e-learning电子教学elected official选任官员c-00/8electronic commerce for developing countries project 发展中国家电子商务项目c-00/2electronic signature电子签名c-00/6electronic signatures and certification authorities电子签名和认证机构c-00/27eligible dependant符合条件的受抚养人c-00/8email reflector电子邮件交流机制(通常采用英文)itu-t/re-nabling以电子方式加强能力；电子实现enabling agent作用力dec.8 (pp-02)enhance ict literacy加强ict知识的普及entitlement应享权利，应享待遇staff regulationsentitlements and benefits福利待遇entrepreneurship创业精神c-01/126entries in the accounts that are still open 未结账目项目c-01/13eradication of poverty消除贫困une-readiness电子就绪established post常设员额established practice惯例/既定做法/常规（做法）c-01/126establishment of an effective spectrum management system 建立一个有效的频谱管理系统c-01/30e-strategy电子战略,信息通信战略c-01/126european broadcasting area欧洲广播区c-01/32evaluation and proposed solutions评估和解决方案提议c-01/20evolving role逐步演进的作用pp-02/245e-working电子办公ex officio vice chairman当然副主席pp-02examine审议(查)，研究c-00/20excess charge附加收费（卫星网络申报）c-03/28exchange gains and losses（外汇）兑换损益exclusive prerogative专有特权c-00/23executive director of es执行秘书处的执行主任executive heads of un agencies 联合国机构的行政首长c-01/17executive secretariat (of wsis) (es) （信息社会世界峰会的）执行秘书处c-01/126executive summary内容提要c-00/12exemption of payment免予缴费c-00/28exercising budgetary controls实行预算控制c-01/2exhibition working capital fund 电信展周转资金c-03/3expected results预期结果c-01/2expenditure支出expenses费用expiry date到期日期，期满日期c-01/22expertise技术专长，专门知识external audit report外部审计报告c-01/54external auditor外部审计员c-01/54external auditor's report 外部审计员报告c-00/1external relations对外关系c-01/2extra budgetary activities 预算外活动c-00/16extra salary increment额外增薪extrabudgetary income 预算外收入c-00/30 extrabudgetary resources 预算外资源c-00/32extraordinary budget特别预算extraordinary expenditure特别支出extraordinary session (of the council)（理事会）非常会议pp-02ffactual information反映事实的资料c-01/14families headed by single or divorced mothers 单身或离婚母亲支撑的家庭c-01/17fellowship与会补贴，研究金fi财务ffield operation dept.驻地工作部(bdt)field operations驻地工作field projects驻地项目c-01/2field office驻地办事处film library（国际电联）电影资料馆final acts最后文件c-00/35final bill最终单据final documents最终文件final list of participants 与会者最终名单final report最后报告c-01/14finance department (fi) 财务部c-00/35financial arrangements 财务安排/协议c-00/16financial base财务基础financial biennium双财务年度c-00/21financial implication财务影响c-00/5financial operating report 财务工作报告c-00/21financial oversight财务监督c-01/20financial plan财务规划financial planning财务规划financial regulations《财务规则》c-01/28financial results财务结算financial rules《财务条例》c-00/21financial statements财务报表c-00/16(itu's) financial systems（国际电联的）财务体系c-03/28financing资金（来源），提供资金，资助，筹资findings审查结果ificfipoi (fr. foundation immeuble pour organisation internationale)国际组织不动产基金会(the) first three downloads of recommendations建议书的前三次下载fixed - term contract定期合同fixed price contract总额包干合同fixed-line network固定线路网络c-01/38flat fee包干收费（卫星网络申报）c-03/28flat rate for boarding包干寄宿费c-01/18floor salary底薪focal point牵头人，召集人focus group焦点组c-00/3follow up落实......的决定，跟踪，后续活动follow-up meetings后续会议follow-up on the external auditor's report 就外部审计员报告采取的后续行动c-00/1for general information供参考c-01/16forum program论坛日程表电信展forum program committee论坛日程安排委员会电信展forward purchase预购（外汇）c-03/3four-year rolling plan四年期滚动计划c-01/28(the) framework of the approved credits for the 2000-2001 biennium2000－2001双年度的已批准款项框架franking privileges免费优待c-01/41free entitlement免费待遇c-03/28frequency management频率管理c-01/17full cost recovery全部成本回收c-00/32full- cost-allocated budget全部成本分配预算full employment (meaning: anybody who is willing to work can get a job in the society)充分就业c-03/30full powers全权证书pp-02functioning (of itu)运作，职能的行使fund balance基金余额fund center资金出账项目c03-add-002funds-in-trust信托基金c-01/28future events: schedule and venue今后的活动：时间表和地点c-01/16futuristic technologies未来的技术c-01/17ggender perspective性别平等观点c-00/1gender-neutral没有性别区分，不分性别gender issue性别问题general概述general council总理事会（wto）general discussion一般性讨论c-01/14general policy and strategy总的政策和战略general rules of conferences, assemblies and meetings of the international telecommunication union《国际电信联盟大会、全会和会议的总规则》c-01/41generic top level domain name类属顶级域名general service category一般事务职类c-01/22geneva diplomatic community network (gdcnet)日内瓦外交使团网络c-00/32geographical balance地域平衡c-01/14geographical distribution地域分配geostationary satellite对地静止卫星c-01/2ggi (group on gender issue)性别问题小组global circulation mechanisms for imt-2000 terminals用于imt-2000终端的全球流通机制c-03/35global directory全球通讯录c-00/35global maritime distress and safety system (gmdss)全球水上遇险和安全系统c-00/47global numbering resources全球号码资源c-03/35global regulators' exchange (g-rex)全球管理机构交流网c-03/add/3glossary词汇表c-00/2gmpcs (global mobile personal communications by satellite) mou全球卫星个人移动通信系统谅解备忘录(good) governance（良好的）治理government advisory committee政府顾问委员会（icann的机构）c-00/27government counterpart contributions in cash (gccc)政府对等部门的现金捐款c-00/21government of the swiss confederation瑞士联邦政府c-01/41grade职位等级staff regulationsgrading定级grand total总计grants & indemnities补助金与补偿金gratuities谢礼c-03/22gross amounts of separation payments离职偿金总额c-00/8gross base salaries基薪总额c-00/8gross base salary scale基薪总额表group of specialists to review the management of the union 审查国际电联管理专家组c-03/add/16group of specialist (gos)专家组c-03/add/gs (general secretariat)总秘书处c-00/29guarantee deposit保证金guideline指导原则c-00/12hhaps (high altitude platform stations)高空平台c-00/35have a wider outreach涉及面更广c-01/17head of the secsec负责人c-01/36heads of regional offices区域代表处负责人c-01/19helpdesk （is dept.）计算机使用问询台c-03/2(add.1)helping the world communicate为世界沟通牵线搭桥helping all of the world's people communicate 为全世界人民之间的沟通牵线搭桥wtd/sgmessage-03high level committee高级委员会c-00/9hlsoc (high level summit organizing committee)峰会高级组委会home leave回籍假staff regulations(the) holy see教廷hrd (human resources development)人力资源开发c-01/17human capacity人的能力c-01/126iiadb美洲开发银行icp（internet content provider）因特网内容提供商icsc (international civil service commission)国际公务员制度委员会ict information and communications technologies）信息通信技术c-01/17ict for all: empowering people to cross the digital divide “为所有人服务的信息通信技术：赋予人们跨越数字鸿沟的能力”ict-enabled development基于信息通信技术的发展c-01/126"ict: leading the way to sustainable development"(the theme for world telecommunication day 2004)“信息通信技术：通向可持续发展之路” （2004年世界电信日的主题）c-03/30identifiable costs确定的费用if (as, where) appropriate需要时，适宜时，酌情if (as, where) necessary必要时，如有必要ilce拉丁美洲通信教育学院ilo/itu staff health insurance fund (shif)国际劳工组织/国际电联职员健康保险基金（shif）c-01/13immunities豁免权c-00/1implementation mechanism实施机制implication影响c-00/6imt-2000 and beyondimt-2000及未来技术in light of the above鉴于上述情况c-01/22position of the members states in relation to the acts of the union on 31 dec. 2002截至2002年12月31日受国际电联各法律文件制约的会员国状况c-03/35incentives鼓励性措施c03-add-016income estimates收入估算c-03/2 （预算）income surplus收入盈余incorporated by reference引证归并pp-02/78incremental cost增加成本c-01/15incumbent operators主体运营商（前垄断运营商）indent缩进段落c-03/96independent facilities management contractor设施管理独立承包方（商）independent telecommunication regulatory agencies独立电信监管机构c-01/38indicative standard指示性标准c-00/12indicative voting表态性表决pp-02indigenous people原住民industry fora行业论坛c-01/38industry members业界成员c-01/28informal group of experts非正式专家组c-01/14informatics信息处理技术information and communication technology capital fund 信息通信技术资本基金c-03/21information bulletin情况通报conventioninformation document情况通报文件c-01/div/5information letter情况通报函wsis-prepcom3-005information services department信息服务部c-00/35information session (council)情况通报会（理事会）c-00/3information systems audit and control organization (isaca) 信息系统审计和控制组织c-03/63(the) information systems users' group of the geneva diplomatic community (isug)日内瓦外交使团信息系统用户组c-00/32informs the council向理事会通报c-01/13input输入（意见）c-01/12installation grants安置津贴instructs责成（在决议、决定中）instruments（法律）文件，法规，证书c-00/35instruments of ratification批准证书c-00/35integrated sap financial system综合sap财务体系c-01/54integrated voice, data and multimedia services 话音、数据和多媒体综合业务c-01/14inter-american proposal美洲国家提案pp-02/249interconnection互连c-01/14interest on overdue payments欠款利息c-00/20interim meetings中期会议interim report中期报告c-00/1internal audit内部审计c-00/35internal auditor内部审计员c-01/54internal functioning mechanism内部运行机制internal service level indicators内部服务水平指标c-01/2international agreements for electronic funds transfers电子资金转账国际协定c-00/2international comity国际礼让international federation of accountants (ifac)国际会计联合会international frequency information circular (ific)国际频率信息通报itu-rinternational lending国际借贷（方式）c-01/14international network designator (ind)国际网络指配机构c-01/div/5international organization of supreme audit institutions (intosai)国际最高审计机构组织c-03/21international regulatory arrangements国际监管协议c-01/40international telecommunication business environment国际电信商业环境c-01/40international telecommunication regulations (itr)《国际电信规则》c-00/1international telecommunication union国际电信联盟international teletraffic congress国际电信大会internet因特网，（国际）互联网c-00/97internet assigned names authority（iana）因特网域名分配机构c-03/27internet broadcast service (ibs)因特网广播业务c-01/2internet corporation for assigned names and numbers （icann）因特网域名和号码分配公司c-00/27internet domain name system因特网域名系统c-00/27internet domain name system structure and delegations因特网域名系统结构和委托代理c-00/27internet engineering task force（ietf）因特网工程任务组（ietf）c-00/27。

翻译当中你认为最难翻的

• 2：三纲五常principle of feudal moral conduct • 解释：三纲：指君为臣纲，父为子纲，夫为妻纲； • 五常：指仁、义、礼、智、信 • 仁义礼智信”为儒家“五常”，孔子提出 “仁、义、礼”，孟子延伸为“仁、义、礼、智”，董仲舒扩充为“仁、义、礼、智、信”，后称“五常”。这“五常”贯穿于中华伦理的发展中，成为中国价值体系中的最核心因素。
Associative meaning
• 2：This kind of Chinese CuIture-loaded Words are words with certain associative meaning that falls short of or differs from the corresponding words in English. • In Chinese culture, 菊：隐逸高洁脱俗(hermit, noble, unsullied, refined ); 梅：坚强不屈不挠（strong，perseverance）兰：高洁（noble, unsullied）; 竹：气节积极向上高洁（fine quality，positiveness, virtuousness ）.but in western cultures, they just belong to plant, having no special meanings.
Characteristics of Chinese CuItureloaded Words
• (1) Embedded with unique cultural connotations. • (2) No equivalents in the English language

高三英语艺术批评方法科学严谨单选题30题(带答案)

高三英语艺术批评方法科学严谨单选题30题(带答案)1.In a great art exhibition, the paintings are _____.A.beautifulB.gorgeousC.prettyD.lovely答案：B。

“gorgeous”在形容艺术作品时，有华丽、绚烂的意思，更符合在艺术展览中对绘画作品的较高程度的赞美。

“beautiful”“pretty”“lovely”都比较普通，没有“gorgeous”那样能体现出艺术作品的独特魅力和高水准。

2.The artist is known for his _____ style.A.uniqueB.specialC.particularD.peculiar答案：A。

“unique”强调独一无二，最能体现艺术家特有的风格。

“special”“particular”“peculiar”虽然也有特别的意思，但不如“unique”强烈。

3.The art critic described the sculpture as _____.A.magnificentB.grandC.splendid答案：A。

“magnificent”常用来形容宏伟壮观、令人赞叹的事物，符合对雕塑的描述。

“grand”主要指规模宏大；“splendid”侧重于辉煌灿烂；“luxurious”是奢华的意思，不太适合形容雕塑。

4.The art work is full of _____ details.A.elaborateB.detailedC.minuteplex答案：A。

“elaborate”有精心制作的、详尽的意思，更能体现艺术作品中细节的精致。

“detailed”比较普通；“minute”指微小的；“complex”强调复杂，不太符合这里强调细节丰富的语境。

5.The artist's use of color is very _____.A.creativeB.imaginativeC.originalD.inventive答案：C。

the unit of analysis -回复

the unit of analysis -回复题目：The Unit of Analysis: An In-depth ExplorationIntroduction:In social science research, the unit of analysis refers to the level at which data is collected and analyzed. It determines the scope and scale of the research and plays a crucial role in drawing accurate conclusions. This article aims to provide a comprehensive understanding of the unit of analysis, addressing its definition, significance, types, and considerations in selecting the appropriate unit.Definition and Significance:The unit of analysis refers to the entity or level of analysis chosen for investigation and data collection. It can be an individual, a group, an organization, a community, or any other social phenomenon. Selecting the appropriate unit of analysis is crucial as it determines the generalizability of the findings and the depth of understanding achieved.Types of Units of Analysis:1. Individual Level:The individual level focuses on studying individuals as isolated entities. It allows researchers to understand individual characteristics, behaviors, attitudes, and experiences. Examples of individual-level research include psychological studies exploring personality traits or surveys measuring consumer preferences.2. Group Level:The group level examines the dynamic interaction among individuals within a defined group. It seeks to understand group dynamics, norms, and social processes. Examples of group-level research include studies on team performance or analysis of familial relationships.3. Organizational Level:The organizational level focuses on exploring structures, processes, and behavior within an organization. It often involves analyzing policies, decision-making, and communication patterns. Examples of organizational-level research include studies on leadership styles or investigations into organizational culture.4. Community Level:The community level investigates phenomena that occur at the community or societal level. It explores social, cultural, economic, and political features of a given community. Examples of community-level research include studies on the impact of public policies on social welfare or analysis of voting patterns in an electoral district.Considerations in Selecting the Unit of Analysis:1. Research Objective:The research objective determines the nature of the unit of analysis. For instance, if the aim is to understand individual behavior, the individual-level unit of analysis is suitable. However, if the research objective is to examine the impact of social policies, a community or organizational level would be more appropriate.2. Scope and Generalizability:The scale and scope of the research play a significant role in selecting the unit of analysis. If the focus is to make broad generalizations about a population or society, a community orsocietal level would be chosen. Conversely, if the focus is on specific micro-level phenomena, an individual or group level would be preferred.3. Data Availability and Feasibility:Researchers must consider the availability and feasibility of data collection methods. Some units of analysis may require extensive resources and time, making data collection challenging. It is essential to balance the potential insights gained with the practicality of accessing valid and reliable data.4. Complexity and Interconnectedness:Researchers should consider the complexity and interconnectedness of the phenomenon under study. If the phenomenon requires understanding multi-level relationships, a combination of units of analysis might be necessary. For instance, studying criminal behavior could involve examining individual characteristics, group dynamics, and societal influences.Conclusion:The unit of analysis is a fundamental aspect of social scienceresearch. Selecting the appropriate unit determines the depth of understanding and generalizability of the findings. By considering the research objective, scope, data availability, and complexity of the phenomenon, researchers can make informed decisions in selecting the unit of analysis. Understanding and effectively implementing the unit of analysis enhances the validity and reliability of research, contributing to the advancement of knowledge in social sciences.。

Internet-of-Things(翻译)

Internet of Things1.the definition of connotation内涵The English name of the Internet of Things The Internet of Things, referred to as: the IOT.Internet of Things through the pass, radio frequency identification technology, global positioning system technology, real-time acquisition of any monitoring, connectivity, interactive objects or processes, collecting their sound, light, heat, electricity, mechanics, chemistry, biology, the location of a variety of the information you need network access through a variety of possible things and things, objects and people in the Pan-link intelligent perception of items and processes, identification and management. The Internet of Things IntelliSense recognition technology and pervasive computing, ubiquitous network integration application, known as the third wave of the world's information industry development following the computer, the Internet. Not so much the Internet of Things is a network, as Internet of Things services and applications, Internet of Things is also seen as Internet application development. Therefore, the application of innovation is the core of the development of Internet of Things, and 2.0 of the user experience as the core innovation is the soul of Things.物联网网络的英文名字,称为:物联网。

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高二英语表演技巧单选题50题

高二英语表演技巧单选题50题1. In a performance, which of the following is important for clear enunciation?A. Fast speechB. Soft voiceC. Correct pronunciationD. Loud volume答案：C。

本题主要考查表演中清晰表达的要素。

选项A 快速说话不利于清晰表达；选项 B 轻声不利于观众听清；选项 D 音量大不一定能保证清晰的发音，而正确的发音（Correct pronunciation）是清晰表达的关键。

2. When emphasizing a particular word in a line, what should be done?A. Speak louderB. Speak fasterC. Pause before the wordD. Increase the pitch答案：A。

在强调一个特定的词时，可以通过更大的音量（Speak louder）来突出它。

选项B 说话更快不利于强调；选项C 在词前停顿不一定能起到强调作用；选项D 提高音调不一定是最有效的强调方式。

3. What can help make the dialogue more engaging in a performance?A. Monotonous toneB. Varying intonationC. Slow paceD. Low volume答案：B。

在表演中，变化的语调（Varying intonation）可以使对话更吸引人。

选项A 单调的语调会使表演枯燥；选项C 缓慢的节奏不一定能使对话更吸引人；选项D 低音量不利于吸引观众。

4. Which of the following is NOT helpful for good line delivery?A. Slurring wordsB. Clear articulationC. Appropriate pacingD. Expressive facial expressions答案：A。

技能认证船舶英语考试(习题卷6)

技能认证船舶英语考试(习题卷6)说明：答案和解析在试卷最后第1部分：单项选择题，共30题，每题只有一个正确答案,多选或少选均不得分。

1.[单选题]Automatic identification systems（AIS）are required to ______.A)provideB)receiveC)exchangeD)all2.[单选题]A printer would be considered a(n) ______.A)controllerB)peripheralC)inputD)US3.[单选题]The main objective of the SOLAS Convention is ______.A)toB)toC)toD)to4.[单选题]Anti-Virus protects your computer from viruses by ___your computer's memory and disk devices.A)deletingB)changingC)replacingD)scanning5.[单选题]What would the amps be at 240 volts with an 8 ohm resistance?A)32.5B)25C)3D)306.[单选题]A feedback is an input ______.A)whichB)whichC)whichD)which7.[单选题]A process of comparing the actual performance of a machine with the intended performance, andC)combiningD)integral8.[单选题]The difference between measured and desired values is called _________.A)offsetB)errorC)deviationD)set9.[单选题]In the bridge or engine control room ACP of AC C20, the telegraph is ______.A)theB)theC)theD)the10.[单选题]For revolution speed regulating, a ______ can give stepless speed regulation.A)governorB)frequencyC)speedD)frequency11.[单选题]Electro-technical officers are working under the leadship of the ______.A)masterB)shipC)engineerD)chief12.[单选题]______ is not the dry cargo vessel.A)TheB)TheC)TheD)The13.[单选题]In a series circuit, which value will remain unchanged at all places in the circuit?A)VoltageB)CurrentC)ResistanceD)In14.[单选题]Radar makes it possible and much safer for us to sail ______.A)inB)inC)inD)in15.[单选题]If both the "high level" and "low level" alarms come on for the same address of a centralized16.[单选题]A ground can be defined as an electrical connection between the wiring of a motor and its_____.A)shuntB)circuitC)metalD)inter-pole17.[单选题]In the 7 inch colour graphics display of ACP in AC C20 system, which information can NOT be displayed?A)TheB)TheC)TheD)The18.[单选题]The operation of paralleling two alternators requires the voltages to be _____ and also in phase.A)zeroB)eliminatedC)differentD)equal19.[单选题]The controlled object and parameter of the fuel oil viscosity control system are ______.A)theB)theC)theD)the20.[单选题]Internet Explorer, Firefox, Google Chrome, Safari, and Opera are the major ______.A)webB)uniformC)fileD)Java21.[单选题]With respect to automatic identification systems（AIS）, which information is expected to be broadcast every 1 to 10 seconds?A)RateB)LatitudeC)NavigationalD)All22.[单选题]In the short circuit protection of the automatic power plant, ______. The purpose of this measure is to prevent the 2nd short circuit.A)theB)theC)theB)theC)theD)the24.[单选题]The ionization sensor is the commonly used detecting device in capacious space; it detects the ______ of fire.A)temperatureB)infraredC)visibleD)smoke25.[单选题]If the resistance of a circuit is cut in half and the applied voltage is kept constant, the current flow will be _____.A)doubledB)quadrupledC)unchangedD)cut26.[单选题]Which of the following does not belong to the power systems of main engine?A)F.O.system.B)C.W.system.C)OilD)Compressed27.[单选题]A centrifuge, of which the bowl is arranged as the upper and lower parts separate, discharges the sludge ______.A)byB)byC)byD)continuously28.[单选题]The most common type of AC service generator found aboard ship is the stationary _____.A)electromagneticB)electromagneticC)armature,D)armature,29.[单选题]______ will form the basis for distress alerting and safety calling.A)GMDSSB)EGC)D)MSIE)DS30.[单选题]The INMARSAT station which can only carry out the telex and data transmission, but not telephone is ______.A)InmarsatB)stationF)stationG)Inmarsat第2部分：判断题，共70题，请判断题目是否正确。

performance is a feast for the eyes 用法

performance is a feast for the eyes 用法Performance Is a Feast for the EyesPerformance art is a unique and captivating form of artistic expression that combines elements of visual arts, music, dance, and theater. It presents a feast for the eyes, engaging spectators in a mesmerizing experience. In this article, we will explore the various aspects of performance art and delve into its impact on both the performers and the audience.1. Origin and Evolution of Performance ArtPerformance art emerged in the late 19th and early 20th centuries as a reaction against traditional forms of artistic expression. Artists sought to break free from the confines of traditional mediums and explore new ways of engaging with their audience. This led to the birth of avant-garde movements, such as Dadaism and Futurism, which paved the way for performance art as we know it today.2. The Fusion of Visual Arts, Music, Dance, and TheaterOne of the defining characteristics of performance art is its ability to incorporate various art forms into a single cohesive piece. Artists utilize their bodies, props, costume, and set design to create visually stunning and emotionally charged performances. The use of music and dance further enhances the sensory experience, adding rhythm, melody, and movement to the artistic expression.3. The Role of the PerformerIn performance art, the performer becomes the medium through which the artistic concept is realized. They use their body, gestures, and expressions to communicate abstract ideas and engage the audience on a deeper level. The performer's presence and energy captivate the spectators, drawing them into the world of the performance and allowing them to experience the artist's vision firsthand.4. Interaction and Audience ParticipationUnlike traditional art forms that remain static, performance art often involves direct interaction with the audience. Spectators may be invited to participate in the performance, blurring the boundaries between performer and viewer. This creates a dynamic and immersive experience, fostering a sense of connection and engagement between the artist and the audience.5. Emotion and Social CommentaryPerformance art has the power to evoke strong emotions and provoke thought. Artists use their performances to communicate their perspectives on social, political, and cultural issues, opening up dialogues and sparking conversations. By pushing boundaries and challenging societal norms, performance art can be a catalyst for change and a powerful tool for social commentary.6. Performance Art in Contemporary SocietyIn today's digital age, performance art has found a new platform for expression. Artists can reach a wider audience through livestreaming, online platforms, and social media. This accessibility allows for greater exposureand encourages experimentation and innovation within the performance art community.7. The Impact on the AudienceAttending a performance art piece can be a transformative experience for the audience. It provides an opportunity for self-reflection, intellectual stimulation, and an emotional journey. The combination of visual spectacle, musical composition, and physical movement creates a multisensory experience that lingers in the minds of spectators long after the performance has ended.In conclusion, performance art is a feast for the eyes, engaging the audience through its fusion of visual arts, music, dance, and theater. It challenges traditional artistic conventions and offers a unique platform for self-expression and social commentary. By immersing spectators in a dynamic and interactive experience, performance art creates a lasting impact on both the performers and the audience. So next time you have the chance, immerse yourself in a performance and let yourself be captivated by the feast for the eyes that is performance art.。

Design and Performance of a General-Purpose Software Cache

Design and Performance of a General-Purpose Software Cache
Arun Iyengar IBM Research T. J. Watson Research Center P. O. Box 704 Yorktown Heights, NY 10598
Abstract
Software caches are a critical component in improving the performance of many applications including Web servers, databases, and le systems. In order for an application to bene t from caching, it must repeatedly use data which is expensive to calculate or fetch. By caching such data, the application only needs to calculate or fetch the data once. Whenever the data is needed after it has been cached, the application can fetch the data from the cache instead of recalculating it or fetching it from a remote location. Software caches are generally several order of magnitudes slower than processor caches. Processor caches can return data in several nanoseconds. By contrast, caches for dynamic Web pages on Web servers can provide near-optimal speedup by handling several hundred hits per second 6]. Since software caches can a ord to be much slower than processor caches, software caches can provide more features such as complex invalidation and replacement strategies as well as logging cache transactions. This paper describes a General-Purpose Software Cache (GPS Cache) designed to improve performance of a wide variety of applications such as Web servers and databases. Applications add, delete, and query the cache via a set of API function calls. The GPS cache can be con gured to store data in memory, on

卓尔精灵语言简介

卓尔精灵语言简介卓尔精灵语言简介卓尔精灵的口语就像其他精灵语言一样丰富、优美，听起来犹如音乐一般。

卓尔精灵能轻易地复述其它语言的声音。

他们大都是优秀的复述者，可以模仿转述他无意中听见的讲话，而且大半部分(55%左右，随着此卓尔精灵对这种语言的熟悉的程度提高而提高)字词和语调都与说话者所讲的无异。

多数卓尔精灵都没怎么接触过地表的语言（流亡者、奴隶贩子和冒险者是比较主要的例外）。

一位居住在地底城市而且很少外出冒险的卓尔精灵会两种语言：卓尔精灵的日常语言，或者叫"地底卓尔语"（各个聚居地之间会有些细微差异，就好像通用语的重读、发音和词汇会因为国家地域的不同而不同一样）；以及卓尔精灵很久以前发明的用手势姿态和面目表情来传达的无声语言。

卓尔精灵的“寂语”-有时也被称为“手语”-是一种和口语一样详尽的语言。

本书中并未给出这种语言的具体细节，这样做基于下面两个原因：第一是伊尔明斯特认为某些秘密还是应该保留的，我自己也十分赞同这点。

第二，进一步发展充实这些姿态和表情属于地下城主发挥创造性的领域，这样可以鼓励玩家进行角色扮演，并且在游戏中加入些不确定性。

而且，熟练做出一种无声语言的细微动作和复杂组合需要好几个月的集中训练。

一个卓尔精灵口语的入门词汇表会在《词汇选摘》一章列出。

“地底卓尔语”（也被称为“低等卓尔语”或“卓尔精灵语”）是卓尔精灵的日常用语，其中混杂着过时的表达方式、交易行话甚至其它语言中的词汇（特别是侏儒语、矮人语、地表精灵语和人类巫师的术语）。

它的结构和通用语-诸国度中人类和大部分种族之间交流所使用的语言-很相像，与地表之下使用的通用语的分支"地底通用语"更是相似。

当书写时，它平滑的字母像极了古代精灵语和托若斯语的自由手写体，但那些对精灵语和通用语都很熟悉的人只能推敲出卓尔精灵文字约14%的大意。

地底卓尔语是一种活生生的、不断变化着的语言，而且随着地域和时代的不同而不同（但卓尔精灵的语言因为聚居地的孤立、口口相传的缓慢速度以及坚固的社会等级而不像地表语言那样变化迅速）。

ProsandconsoftheInternet

Pros and cons of the InternetDespite the technological progress that the Internet brings, one must be wary of the "digital divide" that is also creates, according to a Yonsei University professorThe Korea TimesThursday, October 25, 2007By Park Kyu-taeThe Internet may well be the greatest masterpiece of modern culture, the lion of the century in our information and knowledge based society.As Professor Lars Ingelstam of Lingkoping University, Sweden put it, it is the world's largest machine. The Internet is a communicational network connecting virtually all computers around the world in a non-hierarchical manner and an entirely new concept among communication systems.The system allows the reception and delivery of messages anywhere and anytime in the world virtually in real time on the connected computers.It has seen the technological convergence of digital multimedia, information and communications. It has had an enormous impact on social activities as well as the academic and political circles.Starting out as a military application it eventually permeated all industries, government and commerce. It is has spread into the media and publication industries with Internet versions of newspapers, books and much more.These multifaceted applications are making the Internet ever more powerful. The old versions of media are disappearing and new technologies are forever being added such as IPTV.The technological aspects of the Internet rely on its data transmission rules and protocols. It is a well-established system so far. The data channel is not fixed but it takes a path avoiding busy passages among millions of connected routes to a destination. For receiving messages from senders and vice versa, one has to have a unique domain name address and a series of e-mail addresses.E-mail messages arrive at the mail server similar to the local post office or mail box from a remote personal computer connected to the network. It does not matter where one's mail server is, as one can fetch the mails at electronic speed at any time and place.According to World Internet Statistics, the penetration rate of the world Internet usage population is 20.8 percent, 70.2 percent in North America, and 66.5 percent in South Korea as of January 2007.Interestingly the world map showing the distribution of internet networks in color shows that internet use is more or less proportional to the gross national product of each country. Internet usage is now an indispensable tool for daily life and business.It is a great achievement for this country that Wibro (wireless broadband Internet), developed by the Korean telecommunications industry was approved as an international standard by the International T elecommunication Union (ITU) last week.However there is also a reverse trend going along with these developments: The digital divide. This is the gap between those with access to digital information technology, and those without such access. It further marks the rich and the poor. It accentuate s differences in knowledge access among countries.Despite huge efforts in the form of anti-virus vaccines and firewall procedures to protect computers, the Internet is still vulnerable to attacks from hackers and criminals. It is the source of ongoing panic and at times escalates to the level of cyber wars. A recent survey found that 34 percent of users believed their computers were infected with a virus and 84 percent believed their personal information was being spied on without their permission.This is clearly an invasion of personal privacy. Recently Japan announced it would replace its Internet with a brand new version by 2020 that will deliver more reliable data transfers at higher speeds,and be more resistant to viruses and crashes.However, Dr. Ian Brown, Research Fellow at the Oxford Internet Institute, argued the new internet technology proposed didn't appear radically different from the current version.We are about to enter the presidential elections in Korea and the US. Moreover all the president hopefuls will be utilizing the Internet and its diverse utilities, using websites, Blogs, chat groups, emails, YouTube and cell phone messaging.Their effective use is a great help and utilized correctly could bring through a victory.We are enclosed in a tightly woven Internet like a silkworm in a cocoon. A good use of the net, like a spider, is the conduct of wise man. I think the pros of the Internet far outweigh the cons.。

英文作文120字左右（共10篇）

‎‎‎‎‎英文作文‎120字‎左右(共‎10篇)‎篇一：‎‎10篇常‎见高中英‎语作文(‎120词‎)作文‎一 Fo‎r a ‎b ett‎e r u‎n der‎s tan‎d ing‎bet‎w een‎par‎e nts‎and‎chi‎l dre‎n（G‎e ner‎a tio‎n Ga‎p）范‎文一 N‎o wad‎a ys，‎t her‎e is‎oft‎e n a‎lac‎k of‎und‎e rst‎a ndi‎n g b‎e twe‎e n p‎a ren‎t s a‎n d c‎h ild‎r en.‎Chi‎l dre‎n al‎w ays‎pla‎i n t‎h at ‎t hei‎r pa‎r ent‎s ar‎e ou‎t of‎dat‎e， w‎h ile‎par‎e nts‎can‎t a‎p pro‎v e o‎f wh‎a t t‎h eir‎chi‎l dre‎n sa‎y an‎d do‎. Th‎u s，a‎big‎gen‎e rat‎i on ‎g ap ‎i s f‎o rme‎d. T‎h e g‎a p r‎e mai‎n s w‎i de ‎f or ‎m any‎rea‎s ons‎. Ch‎i ldr‎e n w‎a nt ‎t o b‎efr‎e e t‎o ch‎o ose‎the‎i r o‎w n f‎r ien‎d s，‎s ele‎c t t‎h eir‎own‎cla‎s ses‎in ‎s cho‎o l，‎p lan‎the‎i r o‎w nf‎u tur‎e，‎e arn‎and‎spe‎n d t‎h eir‎own‎mon‎e y ，‎a nd ‎g ene‎r all‎y ru‎n th‎e ir ‎o wn ‎l ife‎in ‎a mo‎r ei‎n dep‎e nde‎n t w‎a y t‎h an ‎m any‎par‎e nts‎all‎o w. ‎A lso‎， yo‎u ng ‎c hil‎d ren‎wis‎h to‎be ‎u nde‎r sto‎o d b‎y th‎e ir ‎p are‎n ts，‎but‎mos‎t pa‎r ent‎s do‎n t ‎q uit‎e un‎d ers‎t and‎the‎i r c‎h ild‎r en.‎The‎y re‎g ard‎it ‎a s t‎h eir‎res‎p ons‎i bil‎i ty ‎t o t‎e ach‎the‎i r o‎f fsp‎r ing‎tra‎d iti‎o nal‎bel‎i efs‎. Th‎e y w‎a nt ‎t hem‎to ‎b e o‎b edi‎e nt ‎a nd ‎d o w‎e ll ‎i n s‎c hoo‎l . ‎T her‎e for‎e， m‎i sun‎d ers‎t and‎i ng ‎o fte‎n ar‎i se ‎f rom‎par‎e nts‎ten‎d enc‎y to‎int‎e rfe‎r e i‎n ch‎i ldr‎e n s‎dai‎l y a‎c tiv‎i tie‎s. I‎n my‎opi‎n ion‎， mo‎s tp‎r obl‎e ms ‎b etw‎e en ‎p are‎n ts ‎a nd ‎c hil‎d ren‎cou‎l d b‎e so‎l ved‎by ‎j oin‎t ef‎f ort‎s of‎bot‎h si‎d es ‎t oe‎n han‎c e m‎u tua‎l un‎d ers‎t and‎i ng.‎范文二‎Now‎a day‎s th‎e re ‎i s o‎f ten‎a l‎a ck ‎o f u‎n der‎s tan‎d ing‎bet‎w een‎par‎e nt ‎a nd ‎c hil‎d. P‎a ren‎t s o‎f ten‎pla‎i n a‎b out‎the‎i r c‎h ild‎r en ‎s ue‎a son‎a ble‎beh‎a vio‎r, w‎h ile‎chi‎l dre‎n us‎u all‎y th‎i nk ‎t hei‎r pa‎r ent‎s to‎o ol‎d-fa‎s hio‎n ed.‎The‎n, w‎h en ‎a ch‎i ld ‎h as ‎apr‎o ble‎m, h‎e us‎u all‎y go‎e s t‎o hi‎s in‎t ima‎t e f‎r ien‎d s f‎o rs‎y mpa‎t hy ‎a nd ‎a dvi‎c e, ‎l eav‎i ng ‎h is ‎p are‎n ts ‎t ota‎l ly ‎i n t‎h e d‎a rk.‎The‎r e a‎r e s‎o me ‎p oss‎i ble‎rea‎s ons‎for‎the‎pre‎s ent‎sit‎u ati‎o n. ‎F irs‎t, t‎h e t‎w o g‎e ner‎a tio‎n s, ‎h avi‎n g g‎r own‎up ‎a t d‎i ffe‎r ent‎tim‎e s, ‎h ave‎dif‎f ere‎n t l‎i kes‎and‎dis‎l ike‎s fo‎r th‎e th‎i ngs‎aro‎u nd ‎t hem‎and‎thu‎s ha‎v e l‎i ttl‎e in‎mon‎to ‎t alk‎abo‎u t. ‎S eco‎n d, ‎p are‎n ts ‎a nd ‎c hil‎d ren‎, du‎e to‎the‎mis‎u nde‎r sta‎n din‎g be‎t wee‎nth‎e m, ‎m ay ‎e ven‎fee‎l it‎unf‎o rta‎b le ‎t o s‎i t f‎a ce ‎t o f‎a ce ‎w ith‎eac‎h ot‎h er ‎t alk‎i ng.‎Fin‎a lly‎, wi‎t h t‎h e p‎a ce ‎o f m‎o der‎n li‎f e b‎e ing‎fas‎t er ‎a nd ‎f ast‎e r, ‎b oth‎par‎e nt ‎a nd ‎c hil‎d ar‎e to‎o bu‎s y t‎osp‎a re ‎e nou‎g h t‎i me ‎t o e‎x cha‎n ge ‎i dea‎s, e‎v en ‎i f t‎h ey ‎f ind‎it ‎n ece‎s sar‎y to‎mun‎i cat‎e. A‎sa ‎r esu‎l t, ‎t he ‎g ap ‎b etw‎e en ‎t hem‎is ‎g row‎i ng ‎w ide‎r an‎d wi‎d er.‎To ‎b rid‎g e t‎h is ‎s o-c‎a lle‎dge‎n era‎t ion‎gap‎, in‎my ‎o pin‎i on,‎bot‎h pa‎r(来自‎:WWw‎.Cdf‎D s.C‎o m 池‎锝范‎文网:‎英文作文‎120字‎左右)e‎n t a‎n d c‎h ild‎sho‎u ld ‎m ake‎an ‎e ffo‎r t. ‎T he ‎c hil‎d ren‎sho‎u ld ‎r esp‎e ct ‎t hei‎rse‎n ior‎s. T‎h e o‎l der‎gen‎e rat‎i on,‎on ‎t he ‎o the‎r ha‎n d, ‎s hou‎l d s‎h ow ‎s oli‎c itu‎d e f‎o r t‎h e y‎o ung‎.As‎for‎the‎i r d‎i ffe‎r enc‎e s, ‎b oth‎gen‎e rat‎i ons‎sho‎u ld ‎m ake‎all‎o wan‎c e f‎o r e‎a ch ‎o the‎r. I‎f th‎e y w‎i ll ‎t ake‎the‎fir‎s t s‎t ep ‎b y a‎c tua‎l ly ‎t alk‎i ng ‎t o o‎n e a‎n oth‎e r, ‎i t w‎o n t‎be ‎l ong‎bef‎o re ‎t he ‎a rri‎v al ‎o f a‎bet‎t er ‎u nde‎r sta‎n din‎g be‎t wee‎n pa‎r ent‎and‎chi‎l d. ‎作文二‎E ner‎g yp‎r obl‎e m 范‎文一 h‎o w t‎o so‎l ve ‎t he ‎e ner‎g y p‎r obl‎e m‎ 1.‎有人认为‎解决能源‎危机的方‎法是厉行‎节约。

吉林2024年08版小学6年级上册第三次英语第三单元期末试卷(含答案)

吉林2024年08版小学6年级上册英语第三单元期末试卷(含答案)考试时间：100分钟（总分:120）A卷考试人：_________题号一二三四五总分得分一、综合题(共计100题)1、填空题：__________ (化学反应物) must be carefully measured for successful experiments.2、听力题：The __________ is a region known for its education systems.3、填空题：The squirrel’s tail helps it maintain _______ (平衡).4、填空题：I like to watch ________ (体育赛事) on TV.5、填空题：The ________ was a significant period of artistic achievement.6、听力题：The _____ (game/toy) is fun.7、What is the process of water turning into vapor?a. Condensationb. Evaporationc. Precipitationd. Sublimation答案:b8、What is the main purpose of a computer?A. To singB. To danceC. To calculateD. To draw答案:C. To calculate9、What is the capital of Portugal?A. LisbonB. MadridC. RomeD. Paris答案:A10、听力题：The capital of Hungary is _______.11、填空题：我的朋友喜欢 _______ (活动). 她觉得这很 _______ (形容词)12、填空题：The country known for its hospitality is ________ (以好客闻名的国家是________).13、ts can grow in ______, while others prefer dry soil.(有些植物可以在潮湿的环境中生长，而另一些则喜欢干燥的土壤。

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• Essentially same block-based hybrid coding model as earlier video standards, but with additional features and flexibility • Draft standard continues to evolve. Our work is based on version “TML-8” • Project has become joint with MPEG (JVT) • Expected approval towards end of 2002
H.26L Analysis & Encoding Algorithms © Anthony Joch, 2002
14
H.26L Analysis: Block Size
• Tested various logical combinations of the 7 available block sizes • Using all 7 block sizes can provide 16% bit savings compared to using only 16x16 • > 80% of this gain can be achieved using only the block sizes of 8x8 and larger • 4x4 mode provides no PSNR improvement
I E F G H A a e i m B b f j n C c g k o D d h l p
8
H.26L Analysis & Encoding Algorithms © Anthony Joch, 2002
H.26L vs. H.263 and MPEG-4
• For conversational video applications (low-delay, conversational content) • Required implementation of the same Lagrangian RD-optimization algorithm in all video encoders • All configured for best RD-performance with no consideration of complexity (full search, etc.)
H.26L Analysis & Encoding Algorithms © Anthony Joch, 2002
9
Conversational Video
• Tested several CIF resolution conversational video sequences • Low delay necessary (no B-pictures) • H.263 Baseline • H.263 Conversational High Compression • MPEG-4 Simple Profile • MPEG-4 Advanced Simple (without B pictures) • H.26L with CABAC, 5 reference frames, no Bpictures
H.26L Analysis & Encoding Algorithms © Anthony Joch, 2002
15
Motion Compensation Block Size
Bus, CIF, 30 Hz
36 35 34 33
PSNR (Y) [dB]
32 31
1
30 29 28 27 26 0 200 400 600 800 Bitrate [Kbit/s] 1000 1200 1400 1600
– – – – 24% vs. H.263 CHC 28% vs. MPEG-4 ASP 33% vs. MPEG-4 SP 42% vs. H.263 Baseline
• RD Curves…
H.26L Analysis & Encoding Algorithms © Anthony Joch, 2002
• Conclusions
H.26L Analysis & Encoding Algorithms © Anthony Joch, 2002
2
H.26L
• Key Objectives
– 50% bit rate reduction compared to H.263 version 2 – Non-backward compatible, “back-to-basics” design – Network friendly, error resilient, low delay option
Flo we r
Fo rem
Sequence
H.26L Analysis & Encoding Algorithms © Anthony Joch, 2002 18
Ne ws
80
100
120
H.26L Analysis & Encoding Algorithms © Anthony Joch, 2002
12
Conversational Video
Foreman, CIF, 30 Hz
39 38 37 36 35 34 33 32 31 30 0 200 400 600 800 1000
H.26L Analysis & Encoding Algorithms © Anthony Joch, 2002 4
H.26L
• 7 motion compensation block sizes
16 16
H.26L Analysis & Encoding Algorithms © Anthony Joch, 2002
H.26L
• Residual coding uses 4x4 integer transform with DCT-like properties • Integer transform eliminates problem of rounding mismatch in the inverse transform • Intra-coded blocks predicted in the spatial domain
H.26L Analysis
• Goal is to characterize RD-performance of key H.26L coding features • First step in finding best complexity-performance tradeoffs needed for efficient fast encoding • RD-optimized, full search • Several features tested on a large set of content (14 sequences)
H.26L Analysis & Encoding Algorithms © Anthony Joch, 2002 10
Conversational Video
• H.26L clearly outperforms other standards • Average bit savings provided by H.26L
% Bit savings from variable block size
25 20
15
1&4 1-3
10
1-4 1-6 1-7
5
0
Mo bil e
Sil en tC IF Te mp ete
an CI F
PI
Co as tgu ard
Co nta ine r Fo rem an
Pa ris
Tr ail bla ze rs
H.26L
• Quarter-pixel motion accuracy is the default • Eighth-pixel accuracy is supported as an option that can sometime improve performance, at the cost of complexity • B-frames supported, as in other standards • Powerful deblocking filter in MC loop • Two entropy coding modes
11
Conversational Video
Akiyo, CIF, 15 Hz
42 41
Weighted PSNR [dB]
40 39 38 37 36 35 34 33 H.26L MPEG-4 ASP MPEG-4 SP H.263 CHC H.263 Baseline
0
20
40
60 Bit rate [kbit/s]
1,4 1-3 1-4 1-6 1-7
H.26L Analysis & Encoding Algorithms © Anthony Joch, 2002
பைடு நூலகம்
16
Motion Compensation Block Size
Tempete, CIF, 30 Hz
36 35 34 33
PSNR (Y) [dB]
– Universal VLC: simple single table VLC – Content-adaptive binary arithmetic coding (CABAC) • Higher compression but more complex