murkey_undertow
BmNPV_侵染后不同抗性家蚕品系中肠组织转录组学分析
引用格式：刘 勇，龚椿营，艾均文，等. BmNPV侵染后不同抗性家蚕品系中肠组织转录组学分析[J]. 湖南农业科学，2023（11）：1-9，13. DOI:DOI:10.16498/ki.hnnykx.2023.011.001蚕桑文化是中国文明的起点，至少已有4 000 a 以上的历史。
家蚕作为重要的经济昆虫对人类文化、经济发展贡献巨大。
种桑养蚕至今仍是部分地区农民的重要收入来源。
然而生产上，家蚕始终受到细菌病、病毒病等的侵害，给农户造成一定的经济损失[1]。
其中，以家蚕核型多角体病毒（Bombyx mori nucleopolyhedrovirus，BmNPV）引起的血液型脓病对蚕桑产业的威胁最大，其传染性极强，一旦发病就难以控制[2]。
目前，环境消毒仍是预防蚕桑病害的主要措施，但该防治方法费时费力，严重制约了蚕桑业的发展。
在此背景下，学者们通过传统杂交育种、分子标记育种和转基因育种等方式选育抗性品种来预防家蚕频发性血液型脓病，虽然这种方式前期投入大、开发周期长，但是一旦成功选育出抗性品种，其经济效益、社会效益和生态效益都是不可估量的[3]。
因此，基于材料间所存在的抗性差异而进行家蚕抗病基因筛选、抗病机制解析成为近年来蚕桑领域的热门课题。
BmNPV是一种环状双链DNA的核型多角体病毒，具有包涵体衍生病毒（occlusion-derived virus，ODV）和出芽型病毒（budded virus，BV）2种不同形式，侵染家蚕的方式包括ODV引起的食下感染和BV引起的创伤感染[3]。
BmNPV在家蚕体内复制增BmNPV侵染后不同抗性家蚕品系中肠组织转录组学分析刘 勇，龚椿营，艾均文，薛 宏，何行健，贾超华，陈卓华，任立志（湖南省蚕桑科学研究所，湖南长沙 410127）摘 要：家蚕核型多角体病毒（BmNPV）是造成蚕业严重经济损失的主要病原体之一，主要通过食下感染引发家蚕血液型脓病，中肠是免疫病原体的重要组织器官。
格雷厄姆算法流程
格雷厄姆算法流程格雷厄姆算法是一种用于解决图论中最短路径问题的算法。
它的核心思想是通过不断更新每个节点的最短路径估计值，从而找到从起点到终点的最短路径。
以下是格雷厄姆算法的详细流程：1. 首先，我们需要定义一个图，包含一组节点和边。
每个节点代表一个地点，每条边代表两个地点之间的路径。
这个图应该是有向图，并且边上应该有权重，表示从一个节点到另一个节点的距离。
2. 接下来，我们需要初始化算法的数据结构。
我们创建一个数组D，用于存储每个节点的最短路径估计值。
初始状态下，除了起点节点，其他节点的估计值都设为无穷大。
3. 然后，我们选择起点节点，并将其最短路径估计值设为0。
同时，我们将起点节点放入一个优先队列Q中，以便按照最短路径估计值的大小进行排序。
4. 进入循环，直到优先队列Q为空。
在每次循环中，我们从Q中取出最短路径估计值最小的节点u。
5. 遍历节点u的所有邻居节点v。
对于每个邻居节点v，我们计算经过节点u到达节点v的路径的长度。
如果该长度小于节点v的最短路径估计值，我们更新节点v的最短路径估计值，并将其加入优先队列Q中。
6. 重复步骤4和5，直到优先队列Q为空。
此时，所有的节点的最短路径估计值应该已经确定。
7. 最后，我们可以通过查看数组D的值来获取从起点到其他节点的最短路径长度。
格雷厄姆算法的时间复杂度为O((V + E) log V)，其中V表示节点的数量，E表示边的数量。
该算法在解决最短路径问题方面非常高效，并且在实际应用中得到了广泛的应用。
总结起来，格雷厄姆算法是一种用于解决最短路径问题的有效算法。
通过不断更新节点的最短路径估计值，该算法可以找到从起点到终点的最短路径。
它的核心思想简单明了，易于理解和实现。
在实际应用中，格雷厄姆算法具有广泛的适用性，并且在时间复杂度上表现出色。
通过了解和掌握这个算法，我们可以更好地解决各种图论问题，为实际应用提供有效的解决方案。
机器学习_隐马尔可夫模型HMM
机器学习_隐马尔可夫模型HMM1. 马尔可夫链马尔可夫链是满足马尔可夫性质的随机过程。
马尔可夫性质是无记忆性。
也就是说，这一时刻的状态，受且只受前一时刻的影响，而不受更往前时刻的状态的影响。
我们下面说的隐藏状态序列就马尔可夫链。
2. 隐马尔可夫模型隐马尔可夫模型（Hidden Markov Model，HMM）是统计模型，用它处理的问题一般有两个特征：第一：问题是基于序列的，比如时间序列，或者状态序列。
第二：问题中有两类数据，一类序列数据是可以观测到的，即观测序列；而另一类数据是不能观测到的，即隐藏状态序列，简称状态序列，该序列是马尔可夫链，由于该链不能直观观测，所以叫“隐”马尔可夫模型。
简单地说，状态序列前项能算出后项，但观测不到，观测序列前项算不出后项，但能观测到，观测序列可由状态序列算出。
HMM模型的主要参数是λ=(A,B,Π)，数据的流程是通过初始状态Pi生成第一个隐藏状态h1，h1结合生成矩阵B生成观测状态o1，h1根据转移矩阵A生成h2，h2和B再生成o2，以此类推，生成一系列的观测值。
HMM3. 举例1) 问题描述假设我关注了一支股票，它背后有主力高度控盘，我只能看到股票涨/跌（预测值：2种取值），看不到主力的操作：卖/不动/买（隐藏值：３种取值）。
涨跌受主力操作影响大，现在我知道一周之内股票的涨跌，想推测这段时间主力的操作。
假设我知道有以下信息：i. 观测序列O={o1,o2,...oT} 一周的涨跌O={1, 0, 1, 1, 1}ii. HMM模型λ=(A,B,Π)•隐藏状态转移矩阵A 主力从前一个操作到后一操作的转换概率A={{0.5, 0.3,0.2},{0.2, 0.5, 0.3},{0.3, 0.2, 0.5}}•隐藏状态对观测状态的生成矩阵B（3种->2种）主力操作对价格的影响B={{0.6, 0.3, 0.1},{0.2, 0.3, 0.5}}•隐藏状态的初始概率分布Pi（Π）主力一开始的操作的可能性Pi={0.7, 0.2,0.1}2) 代码c) 分析这里我们使用了Python的马尔可夫库hmmlearn，可通过命令 $ pip install hmmlearn安装（sklearn的hmm已停止更新，无法正常使用，所以用了hmmlearn库）马尔可夫模型λ=(A,B,Π)，A,B,Π是模型的参数，此例中我们直接给出，并填充到模型中，通过观测值和模型的参数，求取隐藏状态。
(整理)美国大学英语写作 课后答案PART 5
A NSWER KEYPART FIVE: READINGS FOR WRITINGAnswers are provided starting below for the comprehension questions, the structure/technique questions, and the discussion questions that follow each of the 21 reading selections. In addition, a suggested brief outline is provided for each reading selection. As explained on page 11 of this manual, the outline highlights the thesis of each selection and the main support for that thesis. Suggested Answers for “Thank You”—Alex HaleyNote: The numbers in parentheses refer to relevant paragraphs in the selection.Reading Comprehension Questions, 577-5781. c2. b3. a Answers b and c are too narrow; answer d is too broad.4. d Answers a and c are too narrow; answer b is an idea not mentioned in theselection.5. a Paragraph 16. c Paragraph 287. True Paragraph 148. a Paragraph 149. a Paragraph 2210. c Paragraph 12Structure and Technique,5791. Which pattern or patterns of development does Haley use in his essay? Explain.Answer: Much of “Thank You” is a narration of the story of Haley’s letters. As is usually the case with narration, that story also includes description (especially in paragraphs 1, 4, 19).However, Haley’s conclusion reveals that his essay is meant to be an argument for saying “thank you.” In paragraphs 28–30, he writes of encouraging students to say “thank you.”And to readers—of letters written on his stationery and of this reading—he addresses words that summarize his argument: “Find the good—and praise it.”2. Paragraph 4 contains a vivid description of part of Haley’s Thanksgiving night onthe Murzim. What sensory details (sight, smell, hearing, taste, and/or touch) does he provide?What is the effect of all these details?Answer:Haley provides details that appeal to three senses. First, he appeals to the sense of touch when he writes of the “great, deep draughts” he breathed in and the feeling in his feet of “vibrations from the deep-set, turbine diesels.” He appeals to the sense of sight with the images of the “white cook’s hat and the long apron” and of the movement of water “resistingthe skin of a ship.”And he appeals to the sense of hearing with the words “that slightly hissing sound the sea makes.”The effect of the descriptive details is a peaceful scene that sets the mood for Haley’s thoughts about Thanksgiving and the people he should thank.3. Most of Haley’s essay is about the three thank-you letters he wrote. Why do you think heincluded the anecdote about the helpful man at the airport? How is it related to his point about giving thanks?Answer:By including the anecdote about the helpful airline man, Haley shows that he feels it is important to give thanks to people in everyday situations, not just to our elders.This anecdote provides a transition from his first three letters of thanks (which apply only to the author) to his implied argument that we all should remember to thank others.4. Writers’most common purposes are to inform, to entertain, and to persuade. Whichpurpose—or purposes—do you think Haley has in mind?Answer:The information about Haley’s experiences and conclusions supports his central purpose, which is to persuade readers of the importance of giving thanks (28 and 30). Critical Reading and Discussion,5791. Before Haley decides to write to his loved ones, what series of thoughts and images goesthrough his mind as he reflects on the meaning of Thanksgiving? What is the connection between these traditional images and what Haley finally realizes?Answer:After having cooked dinner on the ship, Haley first thinks about “the historic . . .Pilgrims, Indians”and the foods typically associated with Thanksgiving (5). Yet this conventional imagery is inadequate, and Haley seeks a way to “personally apply” the holiday(6). He then thinks about giving thanks through prayer to God (6–7), but again feelsdissatisfied with this approach (8). Finally, Haley comes up with a more concrete and personal way to celebrate Thanksgiving: to thank the people in his life for all they have done for him (9). By going beyond the images of the holiday, Haley expands the traditional meaning of Thanksgiving to include a personal one.2. Alex Haley was far from home when he decided to thank the important people in his life. Ifhe had remained at home, do you think he would have still thanked these people? Why or why not?Answer:Answers will vary. Some students may say that Haley would probably have continued to take the important people in his life for granted if he had not been far away.They might reasonably argue that he needed time and distance to really appreciate what they had done for him.3. How does Haley feel about the three responses to his thank-you letters? What conclusionsabout human nature does he draw from these responses?Answer:All three letters left Haley “not only astounded, but more humbled than before” (20).The fact that his father was “moved” to answer his letter showed Haley how profoundly the thank-you letter had affected his father (22). By quoting parts of Reverend Nelson’s letter, Haley implies that it brought him great satisfaction to have given the Reverend “welcome reassurance that his career had been appreciated” (23). Grandma’s letter evoked tears from Haley, who is moved by the gratitude that would cause her to spend hours responding to him(24).The three responses reveal something almost “mystical in human nature,”which Haley identifies as the secret “yearning . . . for more of their fellows to express appreciation for their efforts” (25).4. Haley is a world-renowned writer. Who might have influenced his decision to be a writer?What made these people such powerful role models in his life? In general, what would you say are the qualities of a good role model?Answer: Answers may vary, although one reasonable response is that all three people Haley thanked—as well as the other four who had died (10)—helped shape the person he has become and therefore influenced his decision to be a writer. The father’s insistence on the value and beauty of reading probably influenced Haley most profoundly (14). But Haley is also indebted to Reverend Nelson and Grandma, who trained him to be a good and moral human being with positive aspirations.Answers to the final question may vary, but students might cite, as qualities of a good role model, integrity, persistence, resilience, sensitivity, compassion, and the like.Thesis-and-Support OutlineThesis: Writing thank-you letters taught the author the value of showing appreciation.1. His father was touched to learn that he had truly helped his own son (22).2. His school principal was reassured of his own self-worth as a result of an appreciative letter(23).3. His grandmother was just as grateful to him as he was to her (24).Suggested Answers for “Shame”—Dick GregoryNote: The numbers in parentheses refer to relevant paragraphs in the selection.Reading Comprehension Questions, 584-5851. a2. d3. b Answers a, c, and d are too narrow.4. a Answers b, c, and d are too narrow.5. c Paragraph 66. True Paragraph 237. a Paragraph 58. b The entire incident with the Community Chest Fund shows Richard’spride; see also paragraph 28.9. b Richard’s teacher ignores his problems and humiliates him in front of theentire class; see paragraphs 5 through 26.10. b Helene cries over Richard’s humiliation; see paragraph 23.Structure and Technique, 5851. In paragraphs 1 and 2, Gregory mentions several steps he took to impress Helene Tucker.What were they? Why does he include them in his essay?Answer:In order to impress Helene, Gregory brushed his hair, got a handkerchief, washed his socks and shirt every night, shoveled the snow off her walk, tried to make friends with her mother and aunts, and left money on her stoop. He describes those steps in detail because, besides demonstrating his devotion to Helene, they give a clear picture of Gregory’s poverty.2. A metaphor is a suggested comparison. What metaphor does Gregory use in paragraph 5, andwhat is its purpose? What metaphor does he use in the second sentence of paragraph 7, and what does it mean?Answer:In paragraph 5, Gregory uses the metaphor that he was pregnant to suggest the effects of poverty on him—it gave him strange tastes, which pregnant people get. It also filled him (as pregnancy fills someone), but with negative things: poverty, dirt, “smells that made people turn away,” and so on.In the second sentence of paragraph 7, Gregory uses the metaphor of a flying eagle to represent the movement of money. (A picture of an eagle is engraved on one side of a quarter).3. In narrating the incidents in the classroom and in the restaurant, Gregory chooses toprovide actual dialogue rather than merely to tell what happened. Why?Answer:By using the exact words spoken by Helene, the teacher, and himself, Gregory givesa very clear picture of what happened by allowing the reader to “experience” it, rather thansimply hear a general summary. The dialogue between Helene and the teacher shows Helene as an ideal little student who received approval from the teacher. The dialogue between Gregory and the teacher, however, clearly demonstrates Gregory’s eagerness to impress Helene and his unsuccessful, embarrassing attempt to gain the teacher’s approval. If Gregory had merely described what had happened, we would have a much less vivid impression of the characters involved.4. At the end of the essay, Gregory shifts his focus from the classroom to the scene involving the winoat the restaurant. What is the connection between this closing scene and the rest of the essay?Answer:In the body of the essay, Gregory is narrating a time that he was shamed publicly and no one came to his defense. In the closing scene, Gregory realizes that he has done the same thing—that he, too, has witnessed a person being shamed without assisting him. He feels a new kind of “shame,” that of having failed to help another man in need.Critical Reading and Discussion,5861. When Gregory writes, “I never learned hate at home, or shame. I had to go to school forthat” (paragraph 1), he is using irony—an inconsistency between what is expected and what actually occurs. What does he mean by these two statements? What is the effect of his irony?Answer:Gregory means that although his home life was one of poverty and want, his home was not a place of inhumane values, such as hatred and shame. But at school, which on its surface was a more positive place, he was made to feel hatred and shame. The ironic statement intrigues the reader and makes him or her want to know more about what Gregory means.2. What are Gregory’s feelings about his teacher? What were your feelings about her as you readthis essay? What could the teacher have done or said that would not have made Gregory feel ashamed?Answer:Gregory seems sad and resentful that the teacher did not understand why he misbehaved in class and that she assumed he was stupid and a troublemaker. But he also wanted her approval badly, as seen by the Community Chest incident and the fact that he gota “big thrill” out of being chosen to clean the blackboard. Students’ suggestions about theteacher will vary. One possibility: She could have merely thanked Gregory in class and then spoken to him privately later if she doubted that he could contribute to Community Chest.3. Gregory shows how a childhood incident taught him shame. What other important lessons does Gregory learn in this essay? Explain.Answer:From paragraph 3, in which Gregory talks about his accomplishments later in life, we can conclude that he learned he could boost his self-esteem through his own efforts.Paragraph 5 shows that from his own experiences, he learned that children who are hungry and poor may feel invisible and so behave in ways that attract attention. From his experience with the wino, he learned that in order to feel good about himself, he would have to start standing up for other people who were shamed.4. At the end of his essay, Gregory says, “I waited too long to help another man.” Why do youthink he waited so long to assist the wino? What are some reasons people do not always help others who are in need (for example, ignoring a homeless person seated on the sidewalk)?Answer:Gregory probably had many reasons for not helping the wino sooner: embarrassment at drawing attention to himself, reluctance to part with his hard-earned money, not wanting to get in trouble with Mr. Williams, not knowing the wino and thus feeling the affair wasn’t his business, etc. People have similar reasons for not helping others in need. In addition, people who ignore a homeless man may feel that the man’s problems—maybe including substance abuse or mental illness—are so big and deep-rooted that they are not qualified to help him in any effective way.Thesis-and-Support OutlineThesis:Living poor was, for the author, a humiliating experience.1. He was embarrassed in front of his classmates and, worse, in front of Helene Tucker(7-23).2. Everybody knew he was a “worthy boy” who had no Dad and no money (28).3. His self-pity prevented him from helping another poor man, the wino (29-37). Suggested Answers for “I Became Her Target”—Roger WilkinsNote: The numbers in parentheses refer to relevant paragraphs in the selection.Reading Comprehension Questions,589-5901. d2. a3. d Answers a and c are too broad; answer b is not supported by the selection.4. d Answers a, b, and c are too broad.5. d Paragraph 36. a Paragraph 67. b Paragraph 78. b Paragraph 29. c Paragraph 610. d Paragraph 11 (We know that Miss Bean had not intended to knock thepencil from his hand because she gasped when the pencil went flying.) Structure and Technique,5911. Which pattern of essay development—comparison, narration, or description—does Wilkinsuse in most of his essay? Explain.Answe r: Wilkins primarily uses narration. Although description is woven throughout, he is generally telling the story of his family’s move to Grand Rapids and a series of events that occurred there.2. Which kind of transition signal—addition, time, or space—does Wilkins use to move hisessay smoothly from one event to the next? Find at least four different words that are examples of this signal.Answe r: Wilkins uses time signals, including “before” (paragraph 2), “later” (7), “after,” (8), “final,”(11), and “afterward”(11). Time signals are often used in narratives to clarify the time relationships between events.3. In the first paragraph, Wilkins chooses to provide some historical background for his story.Why do you think he chose the specific details mentioned there? What might have been lost if these details had been excluded from the essay?Answe r: The historical events Wilkins lists provide helpful context for the story he is about to tell. By telling readers that he is writing about the World War II era, when the symbolic beginning of the civil rights movement was more than ten years away, he helps readers understand how unusual it was in those days for a single black student to enroll in a formerly all-white school. If Wilkins had not included the details and readers had assumed the story happened more recently, they would have been surprised to read of an all-white school where blacks were considered a novelty.4. A title can offer interesting insights into an essay, especially if the title acquires unexpectedmeanings. Before reading this essay, what did you think the title “I Became Her Target”might refer to? What additional meanings do you think Wilkins intended?Answe r: The first impression most readers are likely to get of the title is that someone “targeted”Wilkins in an unpleasant way, as in “targeted for criticism.”Wilkins’s real meaning seems to be twofold: that Miss Bean made him a “target” for her attention because she wanted to force other students to recognize him as a colleague, and later he became the literal “target” of the eraser she threw.Critical Reading and Discussion,5921. What does Wilkins mean by the term nonstandard person(paragraph 3)? Do you think helater felt more like a “standard” person? Why or why not?Answe r: At first, it seemed that “standard” in the Grand Rapids school could only mean white.As a nonwhite student, Wilkins was made to feel less than normal, adequate, or accepted. By saying in paragraph 11 that he became “just another kid in school,” Wilkins indicates that he came to feel more “standard.”2. Wilkins mentions several ways in which Miss Bean treated him differently from the way hewas treated by the other teachers at Creston. How did her approach differ from theirs? What does this approach reveal about Miss Bean—as a teacher and as a person?Answe r: Unlike Wilkins’s other teachers, who chose to ease him in by ignoring him for a while, Miss Bean made him talk in class immediately. She also asked him questions that required him to do his own thinking, not merely give the “correct”answer. Her approach reveals she was an effective teacher: she realized that if she did not take the lead, the otherstudents would isolate Wilkins. Also, she knew the value of encouraging students to think for themselves and express their own opinions. In addition, her approach reveals she was a sensitive person, concerned about Wilkins’s success in his new school.3. Wilkins says that initially he was Miss Bean’s “incipient teacher’s pet” (paragraph 6). Buthow did Miss Bean’s behavior toward him go beyond mere favoritism? In what way did her treatment of Wilkins affect how his peers regarded him?Answe r: Through her attention to Wilkins, Miss Bean was inviting him to demonstrate to the class that he was an intelligent, normal kid. By forcing him to give answers, to “clean up [another student’s] mess”and to present his opinions, she made it more likely that other students would see him as a person rather than as a “dark presence.”4. In paragraph 7, Wilkins says, “Miss Bean became the first teacher ever to require me tothink.” Prior to Miss Bean’s class, what do you suspect Wilkins—and his classmates—were being taught to do in school? Describe a teacher who gave you “the sense that thinking was part of education.” In your opinion, what can teachers do to get students to think?Answe r: Wilkins’s comment suggests that his other teachers had primarily required him to memorize material and parrot it back. Answers to the rest of the question will vary.Thesis-and-Support OutlineThesis: A teacher helped the first black student in school to be accepted and to learnto think for himself.1. As a black newcomer to an all-white school in a bigoted neighborhood before the era ofcivil rights, the author felt shame for being different (1-3).2. Miss Bean immediately began to give Wilkins “human dimensions” by including him inclass discussion (4-6).3. By requiring Wilkins to give his opinion on facts learned in class, Miss Bean showed him“that thinking was part of education”and that he could “form opinions that had some value” (7-10).4. By (accidentally) knocking a pencil from Wilkins’s hand with a tossed eraser, Miss Beanmade Wilkins “just another kid in school” (11).Suggested Answers for “The Ambivalence of Abortion”—Linda Bird Francke Note: The numbers in parentheses refer to relevant paragraphs in the selection.Reading Comprehension Questions, 596-5971. b2. d3. a Answer b gives an incorrect idea of how the author feels about the abortion;answers c and d are too narrow.4. c Answers a and d are too narrow; answer b does not reflect the author’sconfused feelings about the abortion.5. c Paragraph 66. False Paragraphs 4, 12, 207. d Paragraph 138. a Paragraph 39. c Paragraph 2710. True Paragraphs 5, 10Structure and Technique,597-5981. Which method of introduction—broad-to-narrow, anecdote, or questions—does Francke use?Why do you think she chose this way to begin her essay?Answer:Francke uses an anecdote, the story of how she and her husband decided she should have an abortion. By doing so, she immediately shows the reader that she is writing about something that is a very personal issue for her. In addition, the anecdote sets the tone of ambivalence of the piece (“Oh, how we tried to rationalize it that night”).2. A rhetorical question is one for which no answer is expected. In paragraph 14, Franckeposes an extended rhetorical question. What does she achieve by using this technique?Answer:While telling the reader what thoughts went through Francke’s mind before the abortion, the question also reveals a major source of her doubts: she has a great love and respect for all living things. Also, by framing these ideas in question form, she helps the reader better understand the ambivalence she felt.3. A simile is a figure of speech in which a writer compares one thing to another very differentthing, using the word like or as to bring out a surprising relationship between the two. In paragraph 19, Francke uses a simile when she writes that her baby “was sucked up like ashes after a cocktail party.” Why does she use this particular simile? What view of abortion does it suggest?Answer:The image of ashes being vacuumed up suggests an unimportant bit of trash being cleaned up. Francke uses it to suggest a casual view of abortion in which the fetus didn’t matter.4. Repetition is one way of emphasizing an idea. In the final sentences of her essay, Franckeemploys repetition when she writes, “‘Of course we have room,’I cry to the ghost. ‘Of course, we do.’” What is she emphasizing by repeating the words “of course”? Where does she use repetition in paragraph 3, and what is she emphasizing there?Answer:By repeating “Of course,” she emphasizes that she regrets the abortion and wishes she and her husband could have welcomed the child into their lives. In paragraph 3, she repeats the word “agreed”: “There just wasn’t room in our lives now for another baby. We both agreed. And agreed. And agreed.”This repetition emphasizes the difficulty of the decision, the struggle Francke and her husband had to endure to come to their agreement. Critical Reading and Discussion,5981. In what ways are the staff at Women’s Services considerate to Francke and to the otherpatients? In what ways are they not considerate?Answer:They are considerate in terms of the patients’need for quick efficiency—they do their jobs well. They are cheerful and polite. They are less considerate by not acknowledging the mixed feelings their patients may have been having. By telling one scared patient, “By this afternoon you’ll be dancing a jig,” the aide brushes aside the woman’s fear. They do not appear to offer the women an opportunity to have second thoughts and cancel the abortion 2. Not everyone in this essay responds to abortion in the same way. What different responsesare apparent in Francke’s essay? In your opinion, what are the reasons for these differences?Answer:Francke herself felt sad and confused about her abortion. Other women at the center seemed “dazed,”while others seemed unmoved, as if “they were going right back to Bloomingdale’s.” Students’ answers to the second question will vary.3. At the end of Francke’s essay, the question about whether she supports abortion stillremains. From your sense of the essay, do you think Francke is for or against abortion after having had one? Why?Answer:Students’ answers will vary.4. Francke emphasizes her ambivalence toward abortion throughout the essay. Do you thinkambivalence is a valid position, or is it an easy way to avoid a difficult question? In general, should people have straightforward answers to complex questions? Explain.Answer:Answers will vary.Thesis-and-Support OutlineThesis:Having an abortion was a complex decision the author sometimes regrets having made.1. She and her husband had difficulty rationalizing their decision (1-3).2. Her experiences at the Women’s Services clinic were physically and emotionally revolting(4-22).3. She sometimes sees the “ghost” of her unborn baby and seems to regret her choice (27).Suggested Answers for “Smash Thy Neighbor”—John McMurtryNote: The numbers in parentheses refer to relevant paragraphs in the selection.Reading Comprehension Questions,604-4051. c2. b3. a Answers b and c are too broad; answer d is too narrow.4. d Answers a and c are too narrow; answer b contradicts the author.5. c Paragraphs 5 through 86. b Paragraphs 9 and 107. a Paragraph 188. c Paragraph 149. b Paragraph 1810. dStructure and Technique,605-6061. McMurtry uses several patterns of development in his essay: comparison-contrast,cause-effect, description, narration, and argumentation. Where does he use each of those patterns?Answer:McMurtry uses comparison-contrast in paragraphs 5–8, where he compares football and war, and 9–10, where he contrasts his early joy in football with what the game became.He uses cause-effect in paragraphs 15 and 17–18, talking about the game’s effect and players and audience. Description is found in numerous places, such as paragraph 11, in which he describes his injuries. Narration occurs in in paragraph 2, where McMurtry tells the story of his injury and hospitalization. The entire piece is argumentation—everything the author says is meant to support his argument that football in its present state is too violent. In addition to supporting his case forcefully throughout, he uses two specific argumentation strategies: 1) in paragraph 15, he states an opposing view of football, and 2) he then rebuts that view in paragraphs 16–18.2. McMurtry uses terms such as “body wreckage,”“body shattering,”and “skilledmasochism”to describe organized football. Find three other phrases the author uses to describe football (beginning with paragraph 9). What effect does McMurtry hope this language will have on the reader?Answer:“Brutal circus,”“crippling bodily moves,”“joyless drill,”“people-smashing,”and “angry antagonism” are among the descriptive phrases McMurtry uses. He wants the reader to conclude that football in its present form causes too much harm.3. In paragraph 11, McMurtry provides a series of details about the injuries he has sustainedplaying football. List some of these details. Why do you think he includes these personal details in his essay?Answer:The details McMurtry provides include torn knee ligaments, broken nose, broken jaw, torn ankle ligaments, fractured ankle, fractured ribs, torn cartilage, dislocated fingers and toes, and dislocated shoulder. McMurtry includes such details to give a powerful picture of the toll football has taken on his body and also to show that he is writing about a topic with which he has had considerable experience.4. In “Smash Thy Neighbor,”McMurtry repeatedly describes his own personal experienceswith football. What do these anecdotes contribute to the essay? How do they relate to the larger point he is trying to make?Answer:The anecdotes make it clear that even a thoughtful, intelligent man like McMurtry could become so nearly irrational in his attitude towards football: that he would do things to his opponents that he never would in his other life; that he would play despite injuries that threatened his health; that he became vicious and inhumane. By sharing his own experiences, he makes a persuasive point that organized football has very negative effects.Critical Reading and Discussion,6061. What is McMurtry’s current profession? How might his present position have influenced hisopinions about football?Answer:In paragraph 1, McMurtry says he is a university philosophy teacher. As a scholar and philosopher, McMurtry has probably spent a good deal of time thinking about his former life as a professional athlete. As a philosopher, he would know the works of Aristotle (cited in paragraph 15) and be capable of seeing the difference between the role of stage tragedy and bloody athletic contests.2. The author makes a comparison between war and football. Do you think this is a faircomparison? Why or why not?Answer:Answers will vary.3. According to McMurtry, what qualities of our society are reflected in football? What is youropinion of his analysis?Answer:In paragraph 14, McMurtry cites a Harvard study that says such qualities as “impersonal acceptance of inflicted injury,”the devotion of “organizational goals,”the “ability to turn oneself on and off,” and the desire to win are prized by our society, especially in business. Students’ opinion of the analysis will vary.4. In paragraphs 15–18, McMurtry points out—and then refutes—the belief that football benefitssociety. Do you believe that football and sports in general are harmful or helpful to society?Explain.Answer:Answers will vary.Thesis-and-Support Outline。
隐马尔可夫模型(hmm)的matlab实现
隐马尔可夫模型(HMM)是一种用于对时序数据进行建模和分析的概率模型，特别适用于具有一定的隐含结构和状态转移概率的数据。
在自然语言处理、语音识别、生物信息学等领域中，HMM都有着广泛的应用。
在本文中，我将向您介绍HMM的基本概念和原理，并共享如何使用Matlab来实现HMM模型。
1. HMM基本概念和原理隐马尔可夫模型是由隐含状态和可见观测两部分组成的，其中隐含状态是不可见的，而可见观测是可以被观测到的。
在HMM中，隐含状态和可见观测之间存在转移概率和发射概率。
通过这些概率，HMM可以描述一个系统在不同隐含状态下观测到不同可见观测的概率分布。
HMM可以用状态转移矩阵A和发射矩阵B来表示，同时也需要一个初始状态分布π来描述系统的初始状态。
2. Matlab实现HMM模型在Matlab中，我们可以使用HMM工具箱（HMM Toolbox）来实现隐马尔可夫模型。
我们需要定义系统的隐含状态数目、可见观测的数目以及状态转移概率矩阵A和发射概率矩阵B。
利用Matlab提供的函数，可以方便地计算出系统在给定观测下的概率分布，以及通过学习的方法来调整参数以适应实际数据。
3. 在Matlab中实现HMM模型需要注意的问题在实现HMM模型时，需要注意参数的初始化和调整，以及对于不同类型的数据如何选择合适的模型和算法。
在使用HMM模型对实际问题进行建模时，需要考虑到过拟合和欠拟合等问题，以及如何有效地利用HMM模型进行预测和决策。
总结通过本文的介绍，我们可以了解到隐马尔可夫模型在时序数据建模中的重要性，以及如何使用Matlab来实现HMM模型。
对于HMM的进一步学习和实践，我个人认为需要多实践、多探索，并结合具体应用场景来深入理解HMM模型的原理和方法。
在今后的学习和工作中，我相信掌握HMM模型的实现和应用将对我具有重要的帮助。
我会继续深入学习HMM模型，并将其运用到实际问题中，以提升自己的能力和水平。
以上是我对隐马尔可夫模型的个人理解和观点，希望对您有所帮助。
《系统工程与电子技术》英文版投稿须知
《系统工程与电子技术》英文版投稿须知《系统工程与电子技术》英文版(《Journal of Systems Engineering and Electronics》)是由中国航天科工防御技术研究院、中国宇航学会、中国系统工程学会和北京航天情报与信息研究所联合主办的学术期刊,创刊于1990年，现为双月刊。
本刊栏目主要包括：电子技术，防御电子技术，系统工程，控制理论与实践，软件、算法与仿真，可靠性等。
投稿要求如下：1.投稿时请作者提供本单位保密部门出具的保密审查证明,证明不涉及国家秘密和内部秘密。
切勿投寄涉密稿件，否则后果自负。
2.来稿应具备创新性、科学性和学术性，主题突出、论据充分、文字精炼、数据可靠，具有较高的理论水平和实用价值。
3.论文结构一般为题名、作者姓名、单位(邮编)、摘要、关键词、引言、正文、结论、参考文献及作者简介。
请在联系作者姓名的右上角以“*”表明,并在首页页脚注®Corresponding author o4.英文题名实词不超过1M,摘要100~15呼，关键词3~8个。
摘要必须包含与论文同等量的主要信息，包括目的、方法、结果和结论四要素，以提供梗概为目的，不对论文内容作评论，尽量避免采用特殊字符和数学表达式。
5.若论文受基金项目资助，在首页页脚注明基金项目，如This work was supported by the National Natural Science Foundation of China(60530000)o6.文中所有物理量和单位的用法请参照国家标准GB3100-1993o常数、英文缩写、数学运算符号和函数符号采用正体，矩阵、向量、矢量采用黑斜体,其他变量采用斜体。
7. 比较复杂(如长式、带积分号、连加号、连乘号和繁分式)和需编号(例如后文叙述需提及)的公式另行居中排。
公式按顺序编号，编号右顶格，加括号。
公式后按正常语句要求加标点。
&图表应精选。
哈夫曼树度为m
哈夫曼树度为m
（原创版）
目录
1.哈夫曼树的概念和基本性质
2.哈夫曼树的度为 m 的含义
3.哈夫曼树的构造方法
4.哈夫曼树在数据压缩和编码中的应用
正文
哈夫曼树（Huffman Tree）是一种带权路径长度最短的二叉树，主要用于数据压缩和编码。
它是由美国计算机科学家 David A.Huffman 在1952 年提出的，具有唯一解的性质。
哈夫曼树的度为 m 是指树的每个节点最多有 m 个子节点。
哈夫曼树的构造方法如下：
1.根据输入数据（字符）的出现频率构建一个哈夫曼树。
首先将输入数据中的每个字符作为叶子节点，将其出现的频率作为权值。
2.在所有节点中选择权值最小的两个节点，将它们作为一棵新二叉树的左右子节点，且它们的权值之和作为新节点的权值。
3.将这两个节点从原节点集合中移除，将新节点加入集合。
4.重复步骤 2 和 3，直到只剩下一个节点，这个节点就是哈夫曼树
的根节点。
哈夫曼树在数据压缩和编码中的应用十分广泛。
由于哈夫曼树是带权路径长度最短的二叉树，因此可以实现对原始数据的压缩。
在压缩过程中，将每个字符映射到哈夫曼树中的一个路径，这个路径代表一个编码。
在解压缩时，根据编码沿着哈夫曼树进行路径还原，即可得到原始数据。
哈夫曼编码是一种前缀编码，即任何字符的编码都不是另一个字符编码的前缀，
这保证了解压缩的唯一性。
综上所述，哈夫曼树度为 m，具有唯一解的性质，通过构造哈夫曼树，可以实现数据压缩和编码。
07 就地取材促进科学探究的探索
滨水夏日小屋，西福尔，挪威SUMMER CABIN ON THE COAST, VESTFOLD, NORWAY, 2000建筑设计：雅蒙德／维斯奈斯建筑事务所ＡＲＣＨＩＴＥＣＴＳ： Ｊａｒｍｕｎｄ／Ｖｉｇｓｎａｅｓ Ａｒｃｈｉｔｅｃｔｓ１１ 外景／Ｅｘｔｅｒｉｏｒ ｖｉｅｗ夏日小屋位于挪威南部沿海一处风景幽美的滨水岸边。
要通过一所小屋去提升这里的景色真不是一件容易的事情。
最终的设计方案试图把基地上不同自然空间的边界加以强化，增进了各部分及其过渡空间的沟通与交流。
小屋在橡树林和沙滩之间竖了一道墙，为树林赋予了一种神秘花园的感觉。
小屋在墙面上设置了大门，以其中最重要的空间来控制各个房间之间的联系。
与“门”相比，小屋的其他部分比较内向。
窗户的设置或倾斜，或凹陷，或去掉部分的面板。
通过剖面的设计，建筑有意打破了墙面的概念，力求轻盈而赋有动感。
整个小屋的格局从东到西依次是卧室、餐厅、客厅，正好遵循太阳的轨迹。
小屋的外部墙面由经过防水油处理的橡树板材所覆盖。
屋顶为锌板。
□（张晓黎 译）２３２ 总平面／Ｓｉｔｅ ｐｌａｎ３ 外景／Ｅｘｔｅｒｉｏｒ ｖｉｅｗＴｈｅ ｓｕｍｍｅｒ ｃａｂｉｎ ｉｓ ｓｉｔｕａｔｅｄ ｉｎ ａ ｖｅｒｙ ｂｅａｕｔｉｆｕｌｌａｎｄｓｃａｐｅ ｂｙ ｔｈｅ ｗａｔｅｒ ｏｎ ｔｈｅ ｓｏｕｔｈｅｒｎ ｃｏａｓｔ ｏｆＮｏｒｗａｙ． Ｔｈｅ ｌａｎｄｓｃａｐｅ ｉｓ ｄｉｆｆｉｃｕｌｔ ｔｏ ｉｍｐｒｏｖｅ ｔｈｒｏｕｇｈａ ｂｕｉｌｔ ｓｔｒｕｃｔｕｒｅ．Ｔｈｅ ｓｏｌｕｔｉｏｎ ａｔｔｅｍｐｔｓ ｔｏ ｓｔｒｅｎｇｔｈｅｎ ｔｈｅ ｂｏｒｄｅｒｂｅｔｗｅｅｎ ｔｈｅ ｄｉｆｆｅｒｅｎｔ ｎａｔｕｒａｌ ｓｐａｃｅｓ ａｔ ｔｈｅ ｓｉｔｅ，ｒｅｉｎｆｏｒｃｉｎｇ ｔｈｅ ｕｎｄｅｒｓｔａｎｄｉｎｇ ｏｆ ｔｈｅ ｐａｒｔｓ ａｎｄ ｔｈｅｔｒａｎｓｉｔｉｏｎ ｂｅｔｗｅｅｎ ｔｈｅｍ．Ｔｈｅ ｃａｂｉｎ ｅｓｔａｂｌｉｓｈｅｓ ａ ｗａｌｌ ｂｅｔｗｅｅｎ ｔｈｅ ｏａｋｆｏｒｅｓｔ ａｎｄ ｔｈｅ ｂｅａｃｈ， ｇｉｖｉｎｇ ａ ｓｅｃｌｕｄｅｄ ｇａｒｄｅｎｃｈａｒａｃｔｅｒ ｔｏ ｔｈｅ ｆｏｒｅｓｔ．Ｔｈｅ ｂｕｉｌｄｉｎｇ ｃｒｅａｔｅｓ ａ ｇａｔｅ ｉｎ ｔｈｅ ｗａｌｌ， ｔｏｃｏｎｔｒｏｌ ｔｈｅ ｃｏｎｔａｃｔ ｂｅｔｗｅｅｎ ｔｈｅ ｒｏｏｍｓ ｔｈｒｏｕｇｈ ｔｈｅｍｏｓｔ ｉｍｐｏｒｔａｎｔ ｒｏｏｍ ｏｆ ｔｈｅ ｃａｂｉｎ． Ｔｈｅ ｒｅｓｔ ｏｆ ｔｈｅｂｕｉｌｄｉｎｇ ｉｓ ｋｅｐｔ ｒｅｌａｔｉｖｅｌｙ ｅｎｃｌｏｓｅｄ ｉｎ ｃｏｎｔｒａｓｔ ｔｏｔｈｅ “ｇａｔｅ”． Ｗｉｎｄｏｗｓ ａｒｅ ｅｓｔａｂｌｉｓｈｅｄ ｔｈｒｏｕｇｈｓａｄｄｌｅｂａｇｓ， ｓｅｔｂａｃｋｓ ｏｒ ｂｙ ｒｅｍｏｖｉｎｇ ｐａｒｔ ｏｆ ｔｈｅｐａｎｅｌｌｉｎｇ．Ｔｈｅ ｃｏｎｃｅｐｔｕａｌ ｅｓｔａｂｌｉｓｈｍｅｎｔ ｏｆ ｔｈｅ ｗａｌｌ ｉｓｄｅｌｉｂｅｒａｔｅｌｙ ｕｎｄｅｒｍｉｎｅｄ ｂｙ ｔｈｅ ｓｅｃｔｉｏｎ， ａｔｔｅｍｐｔｉｎｇｔｏ ｌｉｇｈｔｎｅｓｓ ａｎｄ ｍｏｖｅｍｅｎｔ．Ｔｈｅ ｐｒｏｇｒａｍ ｉｓ ｓｔｒｕｃｔｕｒｅｄ ｆｒｏｍ ｅａｓｔ ｔｏ ｗｅｓｔ，ｆｒｏｍ ｓｌｅｅｐｉｎｇ ｔｈｒｏｕｇｈ ｄｉｎｉｎｇ ｔｏ ｔｈｅ ｌｉｖｉｎｇ ｒｏｏｍｆｏｌｌｏｗｉｎｇ ｔｈｅ ｐａｔｈ ｏｆ ｔｈｅ ｓｕｎ．Ｔｈｅ ｆａｃａｄｅｓ ａｒｅ ｃｏｖｅｒｅｄ ｗｉｔｈ ｏｉｌｅｄ ｏａｋ ｐａｎｅｌｌｉｎｇ．Ｒｏｏｆ ｉｓ ｚｉｎｃ． □设计年份／Ｙｅａｒ ｏｆ Ｄｅｓｉｇｎ： １９９８－１９９９施工年份／Ｙｅａｒ ｏｆ Ｃｏｎｓｔｒｕｃｔｉｏｎ： １９９９－２０００业主／Ｃｌｉｅｎｔ： Ｗｉｔｈｈｅｌｄ ａｔ ｔｈｅ ｏｗｎｅｒｓ ｒｅｑｕｅｓｔ设计团队／Ｄｅｓｉｇｎ Ｔｅａｍ： Ｅｉｎａｒ Ｊａｒｍｕｎｄ， ＨａｋｏｎＶｉｇｓｎａｅｓ， Ａｌｅｓｓａｎｄｒａ Ｋｏｓｂｅｒｇ结构顾问／Ｓｔｒｕｃｔｕｒａｌ Ｃｏｎｓｕｌｔａｎｔｓ： Ｉｎｇ． Ｗａｌｔｅｒ Ｊａｃｏｂｓｅｎ承建商／Ｃｏｎｔｒａｃｔｏｒ： ＡＢＶ Ｂｙｇｇｔｅａｍ ＡＳ建筑面积／Ｇｒｏｓｓ Ａｒｅａ： １２０ｍ２摄影／Ｐｈｏｔｏｇｒａｐｈｙ： Ｎｉｌｓ Ｐｅｔｔｅｒ Ｄａｌｅ４５４ 外景／Ｅｘｔｅｒｉｏｒ ｖｉｅｗ５ 细部／Ｄｅｔａｉｌ。
英语介绍小蘑菇的作文简单
Mushrooms,a fascinating part of the natural world,are neither plants nor animals but belong to the kingdom of fungi.They come in various shapes,sizes,and colors,and some are even luminescent,like the glowinthedark mushrooms found in certain tropical regions.Characteristics of Mushrooms:Mushrooms are composed of a network of threadlike structures called mycelium,which grows underground or on decaying organic matter.The part we commonly see,the mushroom cap,is just the fruiting body of the fungus,emerging when conditions are right for reproduction.Types of Mushrooms:There are thousands of mushroom species,ranging from the common button mushroom to the exotic morel.Some are edible and highly prized in cuisine,like truffles and chanterelles,while others,like the deadly Amanita phalloides,are extremely toxic.Growth Conditions:Mushrooms thrive in damp,dark environments and require a source of organic material to grow.They play a crucial role in ecosystems by decomposing dead plant and animal matter,thus recycling nutrients back into the soil.Edible Mushrooms:Edible mushrooms are a delicacy in many cultures.They are low in calories and high in nutrients,making them a healthy addition to any diet.Cooking methods vary,from sautéing in butter to using them in soups and stews.Cultivation:Mushroom cultivation is an ancient practice,with some species being farmed for thousands of years.Modern techniques allow for the controlled growth of mushrooms in various substrates,including straw,wood chips,and compost.Conservation and Foraging:While foraging for wild mushrooms can be a rewarding activity,it is essential to be knowledgeable about the species to avoid consuming toxic varieties.Additionally,some mushroom species are endangered and require protection to prevent overharvesting. Medicinal Uses:Mushrooms have been used in traditional medicine for centuries.Some,like the reishi and shiitake,are believed to have immuneboosting and antiinflammatory properties.Culinary Delights:In cooking,mushrooms can be the star of the dish or a flavorful addition to enhance other ingredients.They can be used in a variety of dishes,from pizzas to pasta,and even as a meat substitute in vegetarian and vegan diets.Mythology and Culture:Mushrooms have also captured the human imagination,featuring in myths and legends across cultures.They are often associated with mystery and the supernatural,reflecting their unique place in the natural world.In conclusion,mushrooms are a diverse and intriguing group of organisms that offer both practical and cultural significance.Whether foraging in the wild,cultivating at home,or enjoying in a meal,there is much to appreciate and learn about these fascinating fungi.。
马尔可夫链蒙特卡洛方法中的随机漫步尺度调整技巧(四)
马尔可夫链蒙特卡洛方法中的随机漫步尺度调整技巧马尔可夫链蒙特卡洛方法（MCMC）是一种重要的统计学习方法，广泛应用于贝叶斯推断、机器学习和大数据分析等领域。
在MCMC方法中，随机漫步（Random Walk）是一种常用的采样算法，而随机漫步的尺度调整技巧则是保证算法收敛性和采样效率的重要手段。
一、随机漫步的基本原理随机漫步是一种基于概率的随机移动方式，其核心思想是在当前位置附近随机选择一个新的位置，并以一定的概率接受这个新位置作为下一步的移动位置。
在MCMC方法中，随机漫步被应用于参数空间的遍历和采样，通过不断地在参数空间中进行随机移动，最终收敛到目标分布。
在随机漫步的过程中，尺度的调整是至关重要的。
尺度过大会导致接受概率过低，采样效率低下；尺度过小则会导致在参数空间中长时间徘徊，同样会影响采样效率。
因此，如何合理地调整随机漫步的尺度成为了MCMC方法中的一个重要问题。
二、随机漫步尺度调整技巧1. 自适应尺度调整自适应尺度调整是一种常见的随机漫步尺度调整技巧。
在这种技巧中，随机漫步的尺度会随着采样的进行而自动调整。
具体而言，可以根据接受率来动态地调整尺度大小，以保证接受率在一个合理的范围内。
这样的方法能够有效地平衡随机漫步的探索性和利用性，提高采样效率。
2. 方差调整在一些MCMC算法中，如Metropolis-Hastings算法，参数空间中的随机漫步是通过一个高斯分布来实现的。
在这种情况下，可以通过调整高斯分布的方差来控制随机漫步的尺度。
通常情况下，可以根据接受率来动态地调整高斯分布的方差，以保证接受率的稳定性。
这种方法简单有效，易于实现。
3. 多尺度随机漫步在一些复杂的参数空间中，不同方向上的尺度可能存在差异。
因此，可以考虑使用多尺度随机漫步技巧，即在不同方向上采用不同的尺度来进行随机漫步。
这样的方法能够更好地适应参数空间的结构，提高采样效率。
三、随机漫步尺度调整技巧的应用随机漫步尺度调整技巧在MCMC方法的各个领域都有着广泛的应用。
马尔科夫随机场在金融风险管理中的实际应用经验(八)
金融风险管理一直是金融领域的重要课题，尤其在当前经济环境下，金融机构和投资者需要更有效地管理和控制风险。
传统的风险管理方法已经不能满足现代金融市场的需求，因此，一些新的方法和技术被引入到金融风险管理中。
马尔科夫随机场（Markov Random Field, MRF）作为一种概率图模型，在金融风险管理中的应用引起了人们的广泛关注。
MRF是一种用来描述联合概率分布的图模型，它适用于描述随机变量之间的相互作用关系。
在金融市场中，各种金融资产的价格和波动都受到多种因素的影响，这些因素之间存在复杂的相互作用。
MRF可以很好地描述这些复杂的相互作用关系，因此在金融风险管理中具有很大的应用潜力。
首先，MRF可以用来对金融资产的价格波动进行建模。
金融市场的价格波动不仅受到自身的基本面因素的影响，还受到其他金融资产价格、宏观经济数据、市场情绪等因素的影响。
MRF可以将这些因素之间的相互作用关系进行建模，并通过概率推断的方法来预测金融资产的价格波动。
通过对金融资产价格波动的建模和预测，金融机构和投资者可以更有效地进行风险管理，提高投资收益率。
其次，MRF可以用来进行金融风险的度量和评估。
金融市场的风险来源于多个方面，包括市场风险、信用风险、流动性风险等。
这些风险之间存在复杂的相互关联，传统的风险度量方法往往难以全面考虑这些相互关联。
MRF可以很好地描述这些风险之间的相互关联关系，通过对多种风险因素的联合建模和推断，提高风险度量的准确性和全面性。
金融机构和投资者可以通过MRF对金融风险进行更全面、更准确的度量和评估，从而更好地进行风险管理和控制。
此外，MRF还可以用来进行金融市场的预测和分析。
金融市场的价格波动和风险变化受到多种因素的影响，这些因素之间存在复杂的相互作用关系。
MRF可以很好地描述这些复杂的相互作用关系，通过对金融市场的多种因素进行联合建模和推断，可以更准确地预测金融市场的未来走势和风险变化。
金融机构和投资者可以通过MRF对金融市场进行更准确、更全面的预测和分析，从而更好地制定投资策略和风险管理策略。
隐马尔科夫模型在游戏开发中的应用实例(九)
隐马尔科夫模型在游戏开发中的应用实例隐马尔科夫模型（Hidden Markov Model，HMM）是一种用来描述一个含有隐藏状态的马尔科夫过程的统计模型。
在游戏开发中，HMM常常被用来模拟玩家的行为模式，以便游戏系统可以根据玩家的行为作出相应的反应，从而提升游戏的趣味性和挑战性。
本文将通过一个具体的游戏开发实例来介绍HMM在游戏开发中的应用。
一、游戏类型介绍我们选取了一款名为《神奇宝贝》的回合制角色扮演游戏作为例子来说明HMM在游戏开发中的应用。
在这款游戏中，玩家扮演的是一个训练师，目标是捕捉各种神奇宝贝，并通过对神奇宝贝的训练和升级来提升自己的实力。
二、玩家行为建模在这款游戏中，玩家可以进行各种行为，比如捕捉神奇宝贝、与其他训练师对战、探索地图等。
我们可以用HMM来建模玩家的这些行为。
首先，我们定义三个隐藏状态：捕捉宝贝、对战、探索。
接着，我们定义玩家行为具有一定的概率转移矩阵，比如在玩家捕捉宝贝的状态下，以一定的概率转移到对战状态或者探索状态。
然后，对于每个隐藏状态，玩家的具体行为又可以视为一个观测序列，比如在捕捉宝贝状态下，玩家可能会进行寻找目标、发现目标、投掷精灵球等一系列行为。
这些行为之间也有一定的概率转移关系。
三、应用实例在《神奇宝贝》游戏中，我们可以通过HMM来模拟玩家的行为模式。
比如，当玩家在一片草丛中寻找目标时，我们可以通过监测玩家的行为序列，来判断玩家当前所处的隐藏状态。
如果玩家频繁地进行寻找目标、发现目标的行为，那么我们可以推断玩家当前处于捕捉宝贝的状态下。
而如果玩家频繁地进行与其他训练师对战的行为，那么我们可以推断玩家当前处于对战状态下。
通过HMM模型，游戏系统可以实时地根据玩家的行为作出相应的反应。
比如，在玩家处于捕捉宝贝状态下时，游戏系统可以增加神奇宝贝出现的概率；而在玩家处于对战状态下时，游戏系统可以匹配其他玩家进行对战。
这样一来，游戏可以更加个性化地满足玩家的需求，提升游戏的趣味性和挑战性。
隐马尔可夫模型详解ppt(有例子_具体易懂)
例（续）
如果第一天为晴天，根据这一模型，在今后七天中天 气为O=“晴晴雨雨晴云晴”的概率为：
隐马尔可夫模型 （Hidden Markov Model, HMM）
在MM中，每一个状态代表一个可观察的 事件 在HMM中观察到的事件是状态的随机函数， 因此该模型是一双重随机过程，其中状态 转移过程是不可观察（隐蔽）的(马尔可夫 链)，而可观察的事件的随机过程是隐蔽的 状态转换过程的随机函数(一般随机过程)。
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度为m的哈夫曼树构造
度为m的哈夫曼树构造哈夫曼树是一种通过构造最优前缀编码而生成的二叉树结构，由于它具有高效率和优异的压缩比，因此被广泛应用于数据压缩、编码和加密等领域。
在哈夫曼树中，每个节点都代表一个字符或者字符集合，并且它们的权值表示该字符或字符集合的出现频率，树的每一个叶子节点所代表的字符集合是唯一的。
构造哈夫曼树的基本思路是通过合并权值最小的两个节点生成一个新节点，其中新节点的权值等于两个节点的权值之和，重复执行该操作直到所有节点被合并成一个节点，此时哈夫曼树构造完成。
在哈夫曼树的构造中，度为m的哈夫曼树是一种特殊情况，它要求构造的哈夫曼树中每个非叶子节点都有m个子节点，其中m≥2。
在构造度为m的哈夫曼树时，我们需要首先确定哈夫曼树的叶子节点，即统计字符出现频率并生成对应的叶子节点。
接下来，我们需要对叶子节点进行合并，以生成度为m的内部节点。
在合并叶子节点的过程中，我们可以采用各种不同的合并策略，如最小值策略、加权平均策略等。
最后，当所有叶子节点被合并成一个节点时，我们的哈夫曼树构造就完成了。
1. 统计字符出现频率，并按照频率从小到大生成m个初始叶子节点。
2. 对于剩余的叶子节点，采用各种不同的合并策略，如最小值策略、加权平均策略等，以生成度为m的内部节点。
3. 对所有节点按照权重值从小到大进行排序。
4. 取出权重最小的m个节点，将它们合并成一个新的内部节点，并将新节点插入哈夫曼树中。
5. 重复执行步骤4，直到所有叶子节点被合并成一个节点，并得到完整的哈夫曼树。
需要注意的是，由于度为m的哈夫曼树要求每个非叶子节点都有m个子节点，因此在执行合并操作时需要考虑生成的内部节点的子节点个数是否已经达到了m。
如果没有达到，则需要继续合并已经排序好的节点，直到生成的节点的子节点个数达到m为止。
总的来说，构造度为m的哈夫曼树需要考虑到节点的排序、合并策略以及子节点的个数等方面，它的复杂度较高，但是通过构造出的哈夫曼树，我们可以大大提高数据压缩、编码和加密等操作的效率和精度。
随机环境中分枝随机游动的极限定理
随机环境中分枝随机游动的极限定理
张美娟
【期刊名称】《《数学年刊A辑》》
【年(卷),期】2013(034)006
【摘要】假定环境平稳遍历,考虑随机环境中的分枝随机游动.在此模型中,粒子以上临界的GaltonWatson过程分枝产生后代,而以一维紧邻随机环境中的随机游动进行运动.令Z_n(B)表示时间n落于B中的粒子数,其中B为R中任一子集.得到了计数测度Z_n(·)经过适当的规范化之后,在"annealed"情形下的中心极限定理.【总页数】10页(P727-736)
【作者】张美娟
【作者单位】中央财经大学统计与数学学院北京100081
【正文语种】中文
【中图分类】O211.6
【相关文献】
1.随机环境分枝过程中的极限定理与大偏差定理新解 [J], 高莹莹
2.带形上随机环境中随机游动的内蕴分枝结构 [J], 洪文明; 张美娟
3.随机环境中有界跳幅的分枝随机游动 [J], 张小玥;张美娟
4.随机环境中分枝过程的几个极限定理 [J], 吕平;胡迪鹤
5.随机环境中多物种分枝随机游动 [J], 吕平;胡迪鹤
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隐马尔可夫模型在自然语言处理中的应用
以上 3 个问题，问题①是评估问题，可以用于判断最佳模 型 ；问 题 ② 是 解 码 问 题 ，可 以 用 于 寻 找 最 有 可 能 生 成 观 察 序 列 的 状 态 序 列 ，常 用 韦 特 比 算 法 进 行 解 决 ；问 题 ③ 是 训 练 问 题 ， 用 于 从 已 有 数 据 中 估 计 模 型 的 参 数 。常 采 用 最 大 似 然 估 计 算 法 (对于已标记的训练集) 或 Baum-Welch 算法 (对于未标记的 训练集)解决。
1 HMM 简介
隐马尔可夫模型可以看成是能够随机进行状态转移并输 出 符 号 的 有 限 状 态 自 动 机 ，它 通 过 定 义 观 察 序 列 和 状 态 序 列 的 联 合 概 率 对 随 机 生 成 过 程 进 行 建 模 。每 一 个 观 察 序 列 可 以 看 成 是 由 一 个 状 态 转 移 序 列 生 成 ，状 态 转 移 过 程 是 依 据 初 始 状 态 概 率 分 布 随 机 选 择 一 个 初 始 状 态 开 始 ，输 出 一 个 观 察 值 后 再 根 据 状 态 转 移 概 率 矩 阵 随 机 转 移 到 下 一 状 态 ，直 到 到 达 某 一 预 先 指 定 的 结 束 状 态 为 止 ，在 每 一 个 状 态 将 根 据 输 出 概
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