chapter4-ERmodel

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ERmodelingER模型

Example: A Hospital Database (1)
The hospital database contains information about patients, doctors, nurses and doctors' prescription to patients. • Each patient is described by his/her SSN, Name, Age, Sex, Weight, Height, Insurer, Address, Phone. • Each doctor is described by his/her SSN, Name, Age, Sex, Phone, Specialty, Years_of_experience.
Example: A Hospital Database (2)
• Each nurse is described by his/her SSN, Name, Age, Sex, Years_of_experience, Phone. • Each prescription is described by Dr_SSN, Dr_Name, Patient_SSN, Patient_Name, Medicine_Name, Dosage, Date. • Each doctor can be the primary physician of at most 20 patients. • Each nurse can care at most 5 patients.
Other concepts: Domain, Superkey, Candidate key, Primary key
Relationships (1)

9 Entity-Relationship Modeling(对应书第12章)

Relationships may be given role names to indicate purpose that each participating entity type plays in a relationship. 可使用角色名称来表明每一个参与联系的实体在联系中的作用
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2.2 Relationship Types 联系类型
Examine examples of individual occurrences of the Has relationship using a semantic net. 用语义网来观察Has联系的每个单独实例
The ’ ●’ symbol represents the entity and the ’ ● ’ symbol represents the relationship.
¾ Sometimes called atomic attribute. 原子属性
¾ 如：Staff实体的salary属性
Composite Attribute 组合属性
¾ Attribute composed of multiple components, each with an independent existence. 由多个部分组成的属性，每个部分可独立存在
Relationship occurrence 联系的实例出现
Uniquely identifiable association, which includes one occurrence from each participating entity type. 一个可唯一标识的关联，涉及参与该联系的每个实体类型的一个实例
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四川大学计算机（软件）学院龚勋

国际经济与贸易(双语)-教学大纲

《国际经济与贸易》教学大纲课程编号：112602B课程类型：□通识教育必修课□通识教育选修课□专业必修课√专业选修课□学科基础课总学时：32 讲课学时： 32学分：2适用对象：金融学（国际金融英文班）先修课程：经济学、金融学一、教学目标本课程的主要目标：本门课程的教学，旨在使学生了解和掌握《国际经济学》中的主要理论和研究方法，并能灵活运用所学的理论和方法研究和分析国际经济领域的问题和现象，认识现象和问题的本质属性。

Through the teaching of this course, students should know and seize the major theories and inquisitive method of the international economics. Meanwhile, students should be able to research and analyze some problem and phenomena and understand the substantial properties in the field of international economy according to the theories and methods studied in this course.二、教学内容及其与毕业要求的对应关系要求学生掌握国际贸易基本理论、基本知识，了解当代国际贸易的热点问题及发展趋势，把握国际贸易理论研究前沿。

学完本课程后，应达到以下基本要求：1、了解国际贸易理论前沿和发展状况，能够理解和掌握国际贸易基本概念、历史、理论、政策、新趋势和新实践等基本知识，掌握国际贸易基本方法和基本知识；2、了解国际贸易实践，通过案例教学把握国际贸易的实际情况，能够理论联系实际解决问题，具有分析和解决国际贸易实际问题的能力和研究、分析和编写报告的能力；3、使学生能够运用所学知识，正确分析和解释国际贸易问题与现象。

ER图

標記法使用三種主要元件標記法使用三種主要元件
– 資料實體 – 屬性 – 關係
實體─ 實體─關係資料模型
–對組織或企業領域中實體、關聯性與資料元素的對組織或企業領域中實體、關聯性與資料元素的詳細邏輯表示方法。詳細邏輯表示方法。
圖 7-5 Diagram之符號表示 E-R Diagram之符號表示
Chapter 6 松谷網路商店的例子

系統分析與設計
理論與實務應用
第 7 章建構系統需求：建構系統需求：建立概念性資料模型( 建立概念性資料模型(上)
Jeffrey A. Hoffer Joey F. George Joseph S. Valacich
Copyright 2002 Prentice-Hall, Inc. Prentice-
資料塑模工具(ER 資料塑模工具(ER-Diagram) (ER資料庫的整體邏輯結構可以用圖形表示，這個圖形稱為實體關係圖，它包含了下列的組成元素：
– (1) 矩形：代表實體類型(Entity Type) 矩形：代表實體類型(Entity – (2) 菱形：代表實體類型與實體類型間之關係 (Relationship) – (3) 橢圓：代表實體類型或關係之屬性(Attribute) 橢圓：代表實體類型或關係之屬性(Attribute) – (4) 直線：把屬性連結到實體類型或把實體類型連結到關係 – (5) 基數(Cardinality)：代表實體類型與實體類型間之關係程度，關係程基數(Cardinality)：代表實體類型與實體類型間之關係程度，關係程度可以是一對一、一對多(或多對一) 度可以是一對一、一對多(或多對一)或者多對多等。客戶編號客戶名稱訂單編號日期
多對多的關係(M:N) 多對多的關係(M:N)

新外研版高二英语选择性必修二Unit3-A-new-chapter课件(精编)可修改全文

What does "everything" mean here?
Rainbow bookstore?
Let’s review the passage.
Please think about the “everything”.
Knowledge? Love of reading?
The day I heard that the Rainbow Bookstore was closing after 50 years of business, I was heartbroken. The bookstore was a place 1__w__h_e_r_e___ anyone could drop in and connect through their love of books.
Read the second part, “the new chapter”, para 5-8, and find out
how the old bookstore opened a new chapter.
Owned by_J_e_nn_i_fe_r_O_a_k_le_y_ With the help of community, the new owner led a _c_a_m_p_a_ig_n_to save the bookstore. Changes (The inside was a __d_if_fe_r_en_t__ world.) 1)A place for__l_ite_r_a_tu_r_e-_lo_v_in_g_ members of the community to get together. 2)A __b_o_o_k_re_a_d_in_g__ being delivered in one area. 3)Shelves selling_s_ta_t_io_n_er_y_, p_o_s_te_rs_a_n_d__gi_ft_s_. 4)A big __sc_r_ee_n_ which was displaying customers’_c_om__m_e_n_ts. 5)A caféselling_o_r_g_an_i_c _fo_o_d. 6)More __c_om__m_u_n_it_y_ events, such as__b_o_ok__re_a_d_in_g_s,_p_o_et_ry__re_c_it_al_s,_

计算机系统概论课后练习答案第四章

F.4Chapter4Solutions4.1Components of the V on Neumann Model:(a)Memory:Storage of information(data/program)(b)Processing Unit:Computation/Processing of Information(c)Input:Means of getting information into the computer.e.g.keyboard,mouse(d)Output:Means of getting information out of the computer.e.g.printer,monitor(e)Control Unit:Makes sure that all the other parts perform their tasks correctly and at thecorrect time.4.2The communication between memory and processing unit consists of two registers:MemoryAddress Register(MAR)and Memory Data Register(MDR).•To read,the address of the location is put in MAR and the memory is enabled for a read.The value is put in MDR by the memory.•To write,the address of the location is put MAR,the data is put in MDR and the WriteEnable signal is asserted.The value in MDR is written to the location speciﬁed.4.3The program counter does not maintain a count of any sort.The value stored in the programcounter is the address of the next instruction to be processed.Hence the name’Instruction Pointer’is more appropriate for it.4.4The size of the quantities normally processed by the ALU is referred to as the word length ofthe computer.The word length does not affect what a computer can compute.A computer with a smaller word length can do the same computation as one with a larger word length;but it will take more time.For example,to add two64bit numbers,word length=16takes4adds.word length=32takes2adds.word length=64takes1add.4.5(a)Location3contains0000000000000000Location6contains1111111011010011(b)i.Two’s Complement-Location0:0001111001000011=7747Location1:1111000000100101=-4059ii.ASCII-Location4:0000000001100101=101=’e’iii.Floating Point-Locations6and7:00000110110110011111111011010011Number represented is1.10110011111111011010011x2−11412iv.Unsigned-Location0:0001111001000011=7747Location1:1111000000100101=61477(c)Instruction-Location0:0001111001000011=Add R7R1R3(d)Memory Address-Location5:0000000000000110Refers to location6.Value storedin location6is11111110110100114.6The two components of and instruction are:Opcode:Identiﬁes what the instruction does.Operands:Speciﬁes the values on which the instruction operates.4.760opcodes=6bits32registers=5bitsSo number of bits required for IMM=32-6-5-5=16Since IMM is a2’s complement value,its range is-215...(215-1)=-32768..32767.4.8a)8-bitsb)7-bitsc)Maximum number of unused bits=3-bits4.9The second important operation performed during the FETCH phase is the loading of theaddress of the next instruction into the program counter.4.10Refer to the following table:Fetch StoreDecode Data Result0001,0110,11001100IR0001,0110,1100MDR01104.11The phases of the instruction cycle are:(a)Fetch:Get instruction from memory.Load address of next instruction in the ProgramCounter.(b)Decode:Find out what the instruction does.(c)Evaluate Address:Calculate address of the memory location that is needed to processthe instruction.(d)Fetch Operands:Get the source operands(either from memory or registerﬁle).(e)Execute:Perform the execution of the instruction.(f)Store Result:Store the result of the execution to the speciﬁed destination.F.4.CHAPTER4SOLUTIONS34.12Considering the LC3instruction formatsADDFetch:Get instruction from memory.Load next address into PC.Decode:It is here that it is determined that the instruction is an add instruction.Evaluate Address:No memory operation so NOT REQUIRED.Fetch Operands:Get operands from registerﬁle.Execute:Perform the add operation.Store Result:Store result in the registerﬁle.LDRFetch:Get instruction from memory.Load next address into PC.Decode:It is here that it is determined that the instruction is a Load Base+offset instruction.Evaluate Address:Calculate the memory address by adding the Base register with the sign extended offset.Fetch Operands:Get value from the memory.Execute:No operation needed so NOT RE-QUIRED.Store Result:Store the value loaded into the registerﬁle.JMPFetch:Get instruction from memory.Load next address into PC.Decode:It is here that it is determined that the instruction is a Jump instruction.Evaluate Address:No memory operation so NOT REQUIRED.Fetch Operands:Get the base register from registerﬁle.Execute:Store the value in PC.Store Result:NOT REQUIRED.**Since we are considering a non pipelined implementation,the instruction phases where no operation is performed may not be present in its execution cycle.4.13F D EA FO E SRx86:ADD[eax]edx100111001100=303 LC3:ADD R6,R2,R61001-111=104 4.14JMP:1100000011000000Fetch:Get instruction from memory.Load next address into PC.Decode:It is here that it is determined that the instruction is JMP.Evaluate Address:No memory operation,so NOT required.Fetch Operands:Get the base register from the registerﬁle.Execute:Load PC with the base register value,x369C.4.15Once the RUN latch is cleared,the clock stops,so no instructions can be processed.Thus,noinstruction can be used to set the RUN latch.In order to re-initiate the instruction cycle,an external input must be applied.This can be in the form of an interrupt signal or a front panel switch,for example.4.16(a)1/(2∗10−9)=5∗108machine cycles per second.(b)5∗108/8=6.25∗107instructions per second.(c)It should be noted that once theﬁrst instruction reaches the last phase of the instruction,an instruction will be completed every cycle.So,except for this initial delay(known aslatency),one instruction will be completed each machine cycle(assuming that there are4no breaks in the sequentialﬂow).If we ignore the latency,the number of instructionsthat will be executed each second is same as the number of machine cycles in a second=5*108.。

E-R图指南

Does every department have a manager?
¡
If so, this is a participation constraint: the participation of Departments in Manages is said to be total (vs. partial). • Every did value in Departments table must appear in a row of the Manages table (with a non-null ssn value!)
name ssn Employees lot Manages since dname did budget Departments
Works_In
since
Database Management Systems 3ed, R. Ramakrishnan and J. Gehrke 6
Weak Entities
Employees
hours_worked hourly_wages vAs in C++, or other PLs, ISA contractid attributes are inherited. vIf we declare A ISA B, every A Contract_Emps Hourly_Emps entity is also considered to be a B entity. Overlap constraints: Can Joe be an Hourly_Emps as well as a Contract_Emps entity? (Allowed/disallowed) Covering constraints: Does every Employees entity also have to be an Hourly_Emps or a Contract_Emps entity? (Yes/no) Reasons for using ISA: To add descriptive attributes specific to a subclass. To identify entitities that participate in a relationship. Database Management Systems 3ed, R. Ramakrishnan and J. Gehrke

Introduction to Management Science 5th Edition, 课后习题答案 Chapter 4

CHAPTER 4 THE ART OF MODELING WITH SPREADSHEETSSOLUTION TO SOLVED PROBLEMS4.S1Production and Inventory Planning ModelSurfs U p p roduces h igh-‐end s urfboards. A c hallenge f aced b y S urfs U p i s t hat t heir d emand i s highly s easonal. D emand e xceeds p roduction c apacity d uring t he w arm s ummer m onths, b ut is v ery l ow i n t he w inter m onths. T o m eet t he h igh d emand d uring t he s ummer, S urfs U ptypically p roduces m ore s urfboards t han a re n eeded i n t he w inter m onths a nd t hen c arries inventory i nto t he s ummer m onths. T heir p roduction f acility c an p roduce a t m ost 50 b oards per m onth u sing r egular l abor a t a c ost o f $125 e ach. U p t o 10 a dditional b oards c an b e produced b y u tilizing o vertime l abor a t a c ost o f $135 e ach. T he b oards a re s old f or $200. Because o f s torage c ost a nd t he o pportunity c ost o f c apital, e ach b oard h eld i n i nventory f rom one m onth t o t he n ext i ncurs a c ost o f $5 p er b oard. S ince d emand i s u ncertain, S urfs U p would l ike t o m aintain a n e nding i nventory (safety s tock) o f a t l east 10 b oards d uring t he warm m onths (May–September) a nd a t l east 5 b oards d uring t he o ther m onths (October–April). I t i s n ow t he s tart o f J anuary a nd S urfs U p h as 5 b oards i n i nventory. T he f orecast o f demand o ver t he n ext 12 m onths i s s hown i n t he t able b elow. F ormulate a nd s olve a l inear programming m odel i n a s preadsheet t o d etermine h ow m any s urfboards s hould b e p roduced each m onth t o m aximize t otal p rofit.Jan Feb Mar Apr May Jun July Aug Sep Oct Nov Dec10 14 15 20 45 65 85 85 40 30 15 15This i s a d ynamic p roblem w ith 12 t ime p eriods (months). T he a ctivities a re t he p roduction quantities i n e ach o f t he 12 m onths u sing r egular l abor a nd t he p roduction q uantities i n each o f t he 12 m onths u sing o vertime l abor.To g et s tarted, w e s ketch a s preadsheet m odel. E ach o f t he 12 m onths w ill b e a s eparate column i n t he s preadsheet. F or e ach m onth, t he r egular p roduction q uantity (a c hanging cell) m ust b e n o m ore t han t he m aximum r egular p roduction (50). S imilarly, f or e ach month t he o vertime p roduction q uantity (a c hanging c ell) m ust b e n o m ore t han t he maximum o vertime p roduction (10). E ach m onth w ill g enerate r evenue, i ncur r egular a nd overtime p roduction c osts, i nventory h olding c osts, a nd a chieve a r esulting p rofit. T he g oal will b e t o m aximize t he t otal p rofit o ver a ll 12 m onths. T his l eads t o t he f ollowing s ketch o f a s preadsheet m odel.The e nding i nventory e ach m onth w ill e qual t he s tarting i nventory (the g iven s tartinginventory f or J anuary, o r t he p revious m onth’s e nding i nventory f or f uture m onths) p lus a ll production (regular a nd o vertime) m inus t he f orecasted s ales. T he e nding i nventory a t t he end o f e ach m onth m ust b e a t l east t he m inimum s afety s tock l evel. T he r evenue w ill e qual the s elling p rice t imes f orecasted s ales. T he r egular (or o vertime) p roduction c ost w ill b e the r egular (or o vertime) p roduction q uantity t imes t he u nit r egular (or o vertime)production c ost. T he h olding c ost w ill e qual t he e nding i nventory t imes t he u nit h olding cost. T he m onthly p rofit w ill b e r evenue m inus b oth p roduction c osts m inus h olding c ost. Finally, t he t otal p rofit w ill b e t he s um o f t he m onthly p rofits. T he f inal s olved s preadsheet, formulas, a nd S olver i nformation a re s hown b elow.Unit Cost (Reg)Unit Cost (OT)Selling Price Holding Cost Starting Inventory<=Max Regular <=Max OTForecasted Sales Ending Inventory>=Safety StockThe v alues i n R egularProduction (C10:N10) a nd O TProduction (C14:N14) s how h ow m anysurf b oards S urfs U p s hould p roduce e ach m onth s o a s t o a chieve t he m aximum p rofit o f $31,150.Set Objective Cell: TotalProfit To: MaxBy Changing Variable Cells:RegularProduction, OTProduction Subject to the Constraints:RegularProduction <= MaxRegular OTProduction <= MaxOTEndingInventory >= SafetyStock Solver Options:Make Variables Nonnegative Solving Method: Simplex LP4.S2Aggregate Planning: Manpower Hiring/Firing/TrainingCool P ower p roduces a ir c onditioning u nits f or l arge c ommercial p roperties. D ue t o t he l owcost a nd e fficiency o f i ts p roducts, t he c ompany h as b een g rowing f rom y ear t o y ear. A lso, d ue to s easonality i n c onstruction a nd w eather c onditions, p roduction r equirements v ary f rommonth t o m onth. C ool P ower c urrently h as 10 f ully t rained e mployees w orking i nmanufacturing. E ach t rained e mployee c an w ork 160 h ours p er m onth a nd i s p aid a m onthly wage o f $4000. N ew t rainees c an b e h ired a t t he b eginning o f a ny m onth. D ue t o t heir l ack o f initial s kills a nd r equired t raining, a n ew t rainee o nly p rovides 100 h ours o f u seful l abor i n their f irst m onth, b ut a re s till p aid a f ull m onthly w age o f $4000. F urthermore, b ecause o f required i nterviewing a nd t raining, t here i s a $2500 h iring c ost f or e ach e mployee h ired. A fter one m onth, a t rainee i s c onsidered f ully t rained. A n e mployee c an b e f ired a t t he b eginning o f any m onth, b ut m ust b e p aid t wo w eeks o f s everance p ay ($2000). O ver t he n ext 12 m onths, Cool P ower f orecasts t he l abor r equirements s hown i n t he t able b elow. S ince m anagement anticipates h igher r equirements n ext y ear, C ool P ower w ould l ike t o e nd t he y ear w ith a t l east 12 f ully t rained e mployees. H ow m any t rainees s hould b e h ired a nd/or w orkers f ired i n e ach month t o m eet t he l abor r equirements a t t he m inimum p ossible c ost? F ormulate a nd s olve a linear p rogramming s preadsheet m odel.Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 1600 2000 2000 2000 2800 3200 3600 3200 1600 1200 800 800This i s a d ynamic p roblem w ith 12 t ime p eriods (months). T he a ctivities a re t he n umber o fworkers t o h ire a nd f ire i n e ach o f t he 12 m onths.To g et s tarted, w e s ketch a s preadsheet m odel. E ach o f t he 12 m onths w ill b e a s eparate column i n t he s preadsheet. F or e ach m onth, t here a re c hanging c ells f or b oth t he n umber o f workers h ired a nd f ired. B ased o n t he v alues o f t hese c hanging c ells, w e c an d etermine t he number o f t rainees a nd t rained e mployees. T he n umber o f l abor h ours g enerated b y t he employees m ust b e a t l east t he r equired l abor h ours e ach m onth. F inally, l abor c osts (for trainees a nd t he t rained w orkforce), h iring c ost, a nd s everance p ay l eads t o a t otal m onthly cost. T he g oal w ill b e t o m inimize t he t otal c ost o ver a ll 12 m onths. T his l eads t o t he following s ketch o f a s preadsheet m odel.Labor Monthly WageHiring Cost Severance PayLabor Hours/Trainee/MonthLabor Hours/Trained Worker/MonthStarting Trained WorkforceMinimum to Start the TraineesNext YearTrained Employees >=Labor Hours Available>=Required Labor HoursWhen a n e mployee i s f irst h ired, h e o r s he i s a t rainee f or o ne m onth b efore b ecoming afully-‐trained e mployee. T herefore, t he n umber o f t rainees (row 14) i s e qual t o t he n umber of w orkers h ired i n t hat m onth, w hile t he n umber o f t rained e mployees (row 15) i s t henumber o f t rained e mployees a nd t rainees f rom t he p revious m onth m inus a ny e mployee that i s f ired. T he l abor h ours a vailable i n e ach m onth e quals t he s umproduct o f t he l abor hours p rovided b y e ach t ype o f w orker (trained o r t rainees) w ith t he n umber o f e ach t ype of e mployee. T he l abor c osts i n e ach m onth a re t he m onthly w age m ultiplied b y t he number o f e mployees. T he h iring c ost i s t he u nit h iring c ost m ultiplied b y t he n umber o f workers h ired. T he s everance p ay i s t he u nit s everance c ost m ultiplied b y t he n umber o f workers f ired. T hen, t he t otal m onthly c ost i s t he s um o f t he l abor c osts, h iring c ost, a nd severance p ay. F inally, t he t otal c ost w ill b e t he s um o f t he m onthly c osts. F or a rbitrary values o f w orkers h ired a nd f ired e ach m onth, t his l eads t o t he f ollowing s preadsheet.The S olver i nformation i s s hown b elow, f ollowed b y t he s olved s preadsheet.Thus, W orkersHired (C11:N11) s hows t he n umber o f w orkers C ool P ower s hould h ire e achmonth a nd W orkersFired (C12:N12) s hows t he n umber o f w orkers C ool P ower s hould f ire each m onth s o a s t o a chieve t he m inimum T otalCost (O26) o f $787,500.Solver ParametersSet Objective Cell: TotalCost To: MinBy Changing Variable Cells: WorkersHired, WorkersFired Subject to the Constraints:N15 >= MinimumToStartNewYearLaborHoursAvailable >= RequiredLaborHours WorkersHired = integer WorkersFired = integer Solver Options:Make Variables Nonnegative Solving Method: Simplex LP。

克鲁格曼国际经济学答案（英文）

Overview of Section IInternational Trade TheorySection I of the text is comprised of six chapters: Chapter 2 Labor Productivity and Comparative Advantage: The Ricardian Model Chapter 3 Specific Factors and Income Distribution Chapter 4 Resources and Trade: The Heckscher-Ohlin Model Chapter 5 The Standard Trade Model Chapter 6 Economies of Scale, Imperfect Competition, and International Trade Chapter 7 International Factor Movements T Section I Overview Section I of the text presents the theory of international trade. The intent of this section is to explore the motives for and implications of patterns of trade between countries. The presentation proceeds by introducing successively more general models of trade, where the generality is provided by increasing the number of factors used in production, by increasing the mobility of factors of production across sectors of the economy, by introducing more general technologies applied to production, and by examining different types of market structure. Throughout Section I, policy concerns and current issues are used to emphasize the relevance of the theory of international trade for interpreting and understanding our economy. Chapter 2 gives a brief overview of world trade. In particular, it discusses what we know about the quantities and pattern of world trade today. The chapter uses the empirical relationship known as the gravity model as a framework to describe trade. This framework describes trade as a function of the size of the economies involved and their distance. It can then be used to see where countries are trading more or less than expected. The chapter also notes the growth in world trade over the previous decades and uses the previous era of globalization (pre-WWI) as context for today’s experience. Chapter 3 introduces you to international trade theory through a framework known as the Ricardian model of trade. This model addresses the issue of why two countries would want to trade with each other. This model shows how mutually-beneficial trade arises when there are two countries, each with one factor of production which can be applied toward producing each of two goods. Key concepts are introduced, such as the production possibilities frontier, comparative advantage versus absolute advantage, gains from trade, relative prices, and relative wages across countries. 4 Krugman/Obstfeld • International Economics: Theory and Policy, Seventh Edition Chapter 4 introduces what is known as the classic Heckscher-Ohlin model of international trade. Using this framework, you can work through the effects of trade on wages, prices and output. Many important and intuitive results are derived in this chapter including: the Rybczynski Theorem, the Stolper-Samuelson Theorem, and the Factor Price Equalization Theorem. Implications of the Heckscher-Ohlin model for the pattern of trade among countries are discussed, as are the failures of empirical evidence to confirm the predictions of the theory. The chapter also introduces questions of political economy in trade. One important reason for this addition to the model is to consider the effects of trade on income distribution. This approach shows that while nations generally gain from international trade, it is quite possible that specific groups within these nations could be harmed by this trade. This discussion, and related questions about protectionism versus globalization, becomes broader and even more interesting as you work through the models and different assumptions of subsequent chapters. Chapter 5 presents a general model of international trade which admits the models of the previous chapters as special cases. This “standard trade model” is depicted graphically by a general equilibrium trade model as applied to a small open economy. Relative demand and relative supply curves are used to analyze a variety of policy issues, such as the effects of economic growth, the transfer problem, and the effects of trade tariffs and production subsidies. The appendix to the chapter develops offer curve analysis. While an extremely useful tool, the standard model of trade fails to account for some important aspects of international trade. Specifically, while the factor proportions Heckscher-Ohlin theories explain some trade flows between countries, recent research in international economics has placed an increasing emphasis on economies of scale in production and imperfect competition among firms. Chapter 6 presents models of international trade that reflect these developments. The chapter begins by reviewing the concept of monopolistic competition among firms, and then showing the gains from trade which arise in such imperfectly competitive markets. Next, internal and external economies of scale in production and comparative advantage are discussed. The chapter continues with a discussion of the importance of intra-industry trade, dumping, and external economies of production. The subject matter of this chapter is important since it shows how gains from trade arise in ways that are not suggested by the standard, more traditional models of international trade. The subject matter also is enlightening given the increased emphasis on intra-industry trade in industrialized countries. Chapter 7 focuses on international factor mobility. This departs from previous chapters which assumed that the factors of production available for production within a country could not leave a country’s borders. Reasons for and the effects of international factor mobility are discussed in the context of a one-factor (labor) production and trade model. The analysis of the international mobility of labor motivates a further discussion of international mobility of capital. The international mobility of capital takes the form of international borrowing and lending. This facilitates the discussion of inter-temporal production choices and foreign direct investment behavior. 。

model-quality

The new work processes should be documented through the models. The models developed should help sharing best practice between different units. The models developed should be helpful in the process of refining the processes. The models developed should teach the software developers about the domain. The models developed should define the scope of the software application. The models developed should help analyze and harmonize the current work processes. The models developed should be used as a procedural tool in everyday work. The models developed should support the use of the software application.
TDT4250 - Model-driven Development of Information Systems, Autumn 2010
Quality of models
• What is quality? • The semiotic model quality framework (SEQUAL) • Based on chapter 4 (4.1-4.8) in book manuscript

definemodel 例子-概述说明以及解释

definemodel 例子-概述说明以及解释1.引言1.1 概述引言是文章中的开篇部分，它旨在介绍文章的主题和背景，引起读者的兴趣并提出文章的目的和重要性。

在本篇文章中，我们将讨论定义模型的概念，并探讨其在实际应用中的作用和意义。

通过对模型的概念、应用范围和特点进行深入分析，我们希望能为读者提供对定义模型的全面理解，进而促进其在实践中的应用和发展。

通过本文的阐述，我们也希望能够激发更多的研究和讨论，为定义模型的研究和应用带来更多的启发和创新。

1.2文章结构1.2 文章结构本文主要包括以下内容：- 引言部分：首先介绍了定义模型的概念，并说明了文章的目的和结构。

- 正文部分：详细介绍了定义模型的概念、应用范围和特点，帮助读者全面了解这一概念。

- 结论部分：总结了文章的主要内容，并展望了定义模型的未来发展方向。

- 结束语：对全文进行了总结，强调了定义模型在实际应用中的重要性。

通过上述结构，读者可以系统地了解定义模型的定义、应用和特点，为进一步研究和应用提供了基础和指导。

1.3 目的：本文的目的主要在于介绍和探讨define model的概念，帮助读者深入了解模型定义的重要性和应用范围。

通过对模型的特点进行分析，可以帮助读者更好地理解define model在实际应用中的价值和作用。

同时，本文还旨在引导读者对模型进行深入思考和研究，探索更多有关define model的可能性，为相关领域的研究和实践提供一定的参考和借鉴。

希望通过本文的阐述，能够为读者提供一些启发和思考，促进对define model 概念的进一步理解和应用。

2.正文2.1 定义模型的概念在科学研究和实践中，模型是对真实世界的简化和抽象。

它是一种用来描述、解释和预测现实世界的工具，可以帮助人们更好地理解复杂的现象和系统。

模型可以是数学模型、统计模型、图形模型等多种形式，其核心作用在于提供一种简单、可控的方式来研究和分析现实世界中的问题。

Chapter 4. Inverse Function Theorem

f (x0 + z) − f (x0) = f (x0)z + ◦(z), as z → 0.
1
2
CHAPTER 4. INVERSE FUNCTION THEOREM
Here ◦(z) denotes a quantity satisfying limz→0 ◦(z)/|z| = 0. The same situation carries over to a real-valued function f in some open set in Rn. A function f is called diﬀerentiable at p0 in this open set if there exists a vector a = (a1, · · · , an) such that
n
f (p0 + z) − f (p0) = ajzj + ◦(z) as z → 0.
j=1
Again one can show that the vector a is uniquely given by the gradient vector of f at p0
∂f
∂f
∇f (p0) = ∂x1 (p0), · · · , ∂xn (p0) .
n
(DF (p0)z)i = aij(p0)xj, i = 1, · · · , m,
j=1
where aij = ∂f i/∂xj is the Jabocian matrix of f . (4.1) shows near p0, that is, when z is small, the function F is well-approximated by the linear map DF (p0) up to the constant F (p0) as long as DF (p0) is nonsingular. It suggests that the local information of a map at a diﬀerentiable point could be retrieved from its a linear map, which is much easier to analyse. This principle, called linearization, is widely used in analysis. The inverse function theorem is a typical result of linearization. It asserts that a map is locally invertible if its linearization is invertible. Therefore, local bijectivity of the map is ensured by the invertibility of its linearization. When DF (p0) is not invertible, the ﬁrst term on the right hand side of (4.1) may degenerate in some or even all direction so that DF (p0)z cannot control the error term ◦(z). In this case the local behavior of F may be diﬀerent from its linearization.

数据库ER图英文

name ssn Employees lot Works_In4 did
dname budget Departments
from
Duration
to
Database Management Systems 3ed, R. Ramakrishnan and J. Gehrke
4
Entity vs. Relationship
2

Constraints in the ER Model:

Database Management Systems 3ed, R. Ramakrishnan and J. Gehrke
Entity vs. Attribute

Should address be an attribute of Employees or an entity (connected to Employees by a relationship)?
8
The Unified Modeling Language
UML has the attractive feature that its constructs can be drawn as diagrams. It encompasses a broader spectrum of the software design process than the ER model.
since did Manages2
ห้องสมุดไป่ตู้
dname budget Departments
ISA
Managers
dbudget
This fixes the problem!
5
Database Management Systems 3ed, R. Ramakrishnan and J. Gehrke

Chapter 4 (me)

English lexicology chapter 4 13
inflectional affixes in English

1. Third Person Singular: "She plays the piano" 2. Past Tense: "She played the piano" 3. Progressive: "She is playing the piano now" 4. Past participle: "She has/had eaten the cookies" 5. Plural: "She has two pianos" 6. Possessive: "Mary's piano needs to be repaired" 7. Comparative: "Mary runs faster than Jack" 8. Superlative: "Mary is the fastest of all"
English lexicology chapter 4
6
Verbs ending in –d, -de, or –mit, take -sion (as in expansion, decision, omission). Allomorphs also occur among prefixes. Their form then depends on the first letter of the verb to which they will be added. A prefix like im- occurs before p, b, or m (e.g. imperfect, imbalance, immobile); its allomorphs are irbefore r (e.g. irresponsible); il- before l (e.g. illogical); in- before all other consonants and vowels (e.g. inflexible, inexcusable); im-, irand il- are thus allomorphs of the morpheme iner 4

曼昆经济学原理微观名词解释2-4(中英)

曼昆经济学原理微观名词解释CHAPER2-4（中英版）CHAPTER 2Thinking Like an EconomistCircular-flow diagram: a visual model of the economy that shows how dollars flow through markets among households and firms循环流量图：一个说明货币如何通过市场在家庭与企业之间流动的直观经济模型。

Production possibilities frontier: a graph that shows the combinations of output that the economy can possibly produce given the available factors of production and the available production technology生产可能性边界：表示在可得到的生产要素与生产技术既定时，一个经济所能生产的产品数量的各种组合的图形。

Microeconomics: the study of how house- holds and firms make decisions and how they interact in markets微观经济学：研究家庭与企业如何做出决策，以及它们如何在市场上相互交易的学科Macroeconomics: the study of economy-wide phenomena, including inflation, unemployment, and economic growth宏观经济学：研究整体经济现象，包括通货膨胀，失业和经济增长的学科。

Positive statements: claims that attempt to describe the world as it is实证表述：试图描述世界是什么样子的观点。

IBM云对象存储系统V3.14.12 Field Replaceable Units参考指南说明书

iv IBM Cloud Object Storage System™ : Field Replaceable Units Reference Guide
Chapter 1. Accesser 3105
Accesser 3105
Appliance marketing name
IBM MTM
Accesser 3105
AJ0E
No
AJ0F
No
AJ0G
No
AJ0H
No
AJ0J
No
AJ0N
Yes
AJ0P
Yes
AJ16
Yes
OS Drive Rail Kit Fan 4 Fan 1, 2, 3 Memory Kit - 8 x 16G DIMMs Dual Port SFP+ 10G NIC Quad Port SFP+ 10G NIC Single Port QSFP 40G NIC Dual Port QSFP 40G NIC Dual Port 10GBase-T NIC SFP+ Optical Module SR SFP+ Optical Module LR QSFP Optical Module SR
AJ0E
No
AJ0F
No
AJ0J
No
AJ0N
Yes
AJ0P
Yes
OS Drive Rail Kit Fan 4 Fan 1, 2, 3 Memory Kit - 8 x 16G DIMMs RAID Card Dual Port SFP+ 10G NIC Quad Port SFP+ 10G NIC Dual Port 10GBase-T NIC SFP+ Module SR SFP+ Module LR

数据库 ER图

Also called information model（信息模型）. Modeling from the viewpoint of users. a middle layer between the real world and the machine world. Mainly used for a database design. The language in which the database designers and users communicate with each other. It should be simple, clear and easy to understand by users.
Huang Jing ,Beijing University of Technology
16
Principles of Database
Chapter 1 Introduction
Entity and its Attributes
These are data in the system! Which one is entity? Which one is attribute? How to confirm?
How to place these data into soft system? It is too difficult to do . we have to turn to IT expert.
computer-independent
Huang Jing ,Beijing University of Technology 14
Key = the set of attributes which can uniquely identify an entity 唯一标识实体的属性或属性集合 Student实体的码是？。。。 Domain = the value range of attributes. 属性的取值范围性别的域为（男，女），学生年龄的域为自然数

Unit 4 Role Models

Text A Whose Lead Should I Follow?
Words and expressions
1. survive vi. 幸存，活下来 e.g. These plants cannot survive in very cold conditions. 这些植物在严寒中不能存活。 vt. 比…活得长;经历…之后还存在 Most parents expect that their children will survive them. 大多数父母都希望子女能够比他们自己长寿。 Did anyone survive the explosion? 那次爆炸事故中有人幸免吗?
Text A Whose Lead Should I Follow? (涉及介词的定语从句1)*
in which, for which, with whom等：定语从句中如涉及介词，介词可放在关系代词（一般是which, whom）之前，或放在定语从句末尾。介词在关系代词前属正式文体，在从句末尾属口语体。 e.g. The girls with whom he worked lived in that building. (正) The girls (who/that) he worked with lived in that building. (口) This is the room in which Shakespeare was born. This is the room (that) Shakespeare was born in.
Talk show host Oprah Winfrey is shown with Nelson Mandela from the episode of "The Oprah Winfrey Show" that originally aired on November 27, 2000 in this publicity photograph released on May 24, 2011.