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Agent-oriented modeling with graph transformation

Agent-oriented modeling with graph transformation
Agent-oriented modeling with graph transformation

Agent-Oriented Modeling with

Graph Transformation

Ralph Depke Reiko Heckel Jochen Malte K¨u ster

Dept.of Computer Science,University of Paderborn

Warburger Str.100,D-33098Paderborn

{depke,reiko,jkuester}@uni-paderborn.de

Abstract.The agent paradigm can be seen as an extension of the notion of(ac-

tive)objects by concepts like autonomy,cooperation,and goal-oriented behavior.

Mainstream object-oriented modeling techniques do not account for these agent-

speci?c aspects.Therefore,dedicated techniques for agent-oriented modeling are

required which are based on the concepts and notations of object-oriented mod-

eling and extend these in order to support agent-speci?c concepts.

In this paper,an agent-oriented modeling technique is introduced which is based

on UML notation.Graph transformation is used both on the level of modeling in

order to capture agent-speci?c aspects and as the underlying formal semantics of

the approach.

1Introduction

As concepts and technologies of agent-based systems become part of more traditional software,agent-based software development is about to become one aspect of main-stream software engineering.Today,most software systems are implemented in an object-oriented programming language like C++or Java,and the analysis and design of such systems is based on object-oriented modeling languages like the UML[16]. Thus,in order to incorporate agent concepts into mainstream software development,an integrated modeling approach for object-and agent-based systems is required.

As modeling concepts,agents and objects have complementary roles:agents act autonomously,driven by their goals and plans,thereby sensing and reacting to their environment and cooperating with other agents.Objects encapsulate data structures and operations and provide services to other objects.In this sense,Jennings,et al.

[15]state that“There is a fundamental mismatch between the concepts used by object-oriented developers...and the agent view.”However,the view of objects as mere ser-vice providers has its origins in the paradigms of sequential OO programming,and is no longer adequate when considering concurrent languages like Java.As a modeling abstraction for concurrent objects,the concept of active object has been established [16]which has much similarity with the agent paradigm.What is still missing even in active objects is the idea of goal-driven behavior or proactivity of agents and the related concept of autonomy.Autonomy emphasizes the fact that an agent has control about its Research supported by the ESPRIT Working Group APPLIGRAPH.

operations:they are not called from outside like methods but are only invoked by the agent itself in order to reach a certain goal.

Still,object-oriented modeling languages like the UML provide a good basis for the modeling of agent-based systems.In fact,a number of authors propose extensions and adaptions of object-oriented modeling languages for agent-based systems[12,21, 20].Most approaches suffer from a problem which is also encountered in OO modeling languages:the lack of adequate means for describing the semantics of operations,their pre-conditions and effects on the system’s con?guration.In particular,the semantics of operations is relevant for the modeling of reactive behavior,i.e.,for the way how agents sense and modify their environment.

Building upon the notation of the UML[16],in this paper we present an agent-oriented modeling technique which employs graph transformation rules1for specifying the effect of the agents’operations.We pay special attention to the modeling of co-operation and autonomy.Graph transformation rules in requirement speci?cation and analysis allow us to capture the cooperation among several agents resulting in a joint activity.In the design phase,graph transformation rules specify the effect of the agents’local operations.Here,the non-determinism inherent to a rule-based approach provides a convenient model for the autonomy of agents.As underlying formal framework,typed graph transformation systems[2]provide a natural integration of structural and dynamic aspects as well as elaborate concepts for de?ning the consistency between requirements speci?cation,analysis,and design(see[4]).

Next,we shall discuss in more detail the relevant properties of agent-based systems as well as the main concepts of our modeling approach.The following sections3to 5are concerned with the three main phases of software modeling(i.e.,requirements speci?cation,analysis,and design).Section6reviews and discusses concepts of roles in object-and agent-oriented modeling,and Section7concludes the paper.

The paper continues previous work on agent-based systems which is documented in[3,5,14].

2Agent-Oriented Modeling

In this Section,we outline our approach to agent-oriented modeling.First,we discuss typical aspects of agent-based systems like reactivity,autonomy,proactivity,and coop-eration,and describe how these aspects are captured in our approach.Then,we survey the three main phases of system modeling,i.e.,requirement speci?cation,analysis,and design and explain how this general pattern is instantiated in our case.

Although it is dif?cult to?nd a general(technical)de?nition of the term agent, some important characteristics of agents can be identi?ed which distinguish them from programs or objects[10].Reactivity is the capability of an agent to perceive its envi-ronment and react to changes.This property can be considered as a prerequisite for purposeful autonomy of agents,and it is already captured within the concept of active objects.In our approach,agents perceive their environment by matching the left-hand 1See,e.g.,[17,6,7]for a recent collection of surveys and[1]for an introductory text.

sides of their transformation rules against the current state of the system,thus search-ing for the occurrence of a certain pattern.Then,agents react to an occurrence by the application of the corresponding rule.

Autonomy is a property of agents that manifests in the nondeterminism of its behav-ior if the system is observed externally.Different to objects,agents possess autonomous operations that are not automatically triggered by messages but may be invoked by the agents themselves when a corresponding situation pattern occurs in their environment. If several autonomous operations are applicable in a particular situation,the decision which operation to apply is internal to the agent.

Agents are proactive meaning that their activities are directed towards a goal.In our approach,this goal-driven behavior is not explicitly modeled.However,there is a close relationship with the(external)nondeterminism of agents’behavior because the decision which operation to apply can be thought of as driven by the internal desire to reach a given goal.Cooperation among agents assumes a common goal which may be negotiated at run-time.In our approach,global graph transformation rules are used in order to describe the combined effect of negotiations and the resulting joint activities of a group of agents.The communication required is speci?ed by means of UML sequence diagrams.

As a simple but typical example of an agent-based system we describe an online banking application where,in order to enable sophisticated services,customers may be assisted by a personal banking agent(PBA)which offers a range of advanced function-ality.In particular,the PBA manages the payment of bills:When a bill is sent to the PBA by the merchant of a shop and the payment of this bill is initiated by the customer, the personal banking agent selects one of the customer’s accounts of which the bill is to be paid.This selection takes into account the transaction cost of each account which is considered.Then,the amount speci?ed in the bill is transfered from the selected account to the destination by account agents responsible for the individual accounts. The system just described has properties that are characteristic for an agent-based sys-tem[10]:The PBA reacts to changes in its environment(like the arrival of a bill)and it modi?es this environment through its actions(by paying it).It acts autonomously on behalf of the customer by choosing the account the bill is to be paid from.The agent is goal-oriented in the sense that it aims at minimizing transaction costs by an appropriate account selection.

We divide the modeling process of agent-based systems in a typical sequence of activities which is already well known from the modeling of object-oriented systems. First,the requirements are speci?ed by informal descriptions of the system’s functional-ity and by scenarios of important interactions.The analysis of this speci?cation results in a model where the requirements are captured more precisely.Thereafter,in the design model the behavior that has been described globally in the analysis model is expressed by the local behavior of objects and agents.Within the requirements speci?cation(Sec-tion3)we follow a use case-driven https://www.doczj.com/doc/f818207696.html,e cases representing the main external functions of the system as well as important internal interactions among agents are re-?ned by typical scenarios which are described by means of global graph transformations and sequence diagrams.During analysis(Section4)the agents and objects as well as their messages,attributes,and links,which are identi?ed in the use cases and scenarios,

are speci?ed in an agent class diagram.The scenarios are analyzed in order to derive a more complete speci?cation making explicit the different alternatives in the execu-tion of a use case.The semantics of graph transformations and sequence diagrams thus shifts from optional to mandatory behavior:If the execution reaches a state satisfying a pre-condition (speci?ed by the left-hand side of a graph transformation rule)the further interaction must follow one of the given alternatives.

The design (Section 5)re?nes the analysis model in such a way that globally de-scribed behavior is mapped to local speci?cations of the behavior of agents and objects.A re?ned class diagram introduces additional features,in particular,the signatures of the agents’autonomous operations.The local execution order of an agent’s operations is determined by a state diagram associated to each agent class.The effect of these operations on the state of the system is described by local graph transformation rules.issue bill

initiate

payment select account

Customer

Merchant pay bill

Account Agent

Bank

Personal

Banking

Agent (PBA)Minimize transaction cost https://www.doczj.com/doc/f818207696.html,e case diagram for banking example

3Requirements Speci?cation

At the beginning of a development,customers and developers have to agree on the re-quirements a software product has to ful?ll.These requirements are collected in a con-tract which has to be readable by the software developers as well as by customers which are typically not computer scientists.Therefore,a style of speci?cation is appropriate which explains the functional and architectural requirements by means of informal dia-grams and examples.

Use case diagrams are designed exactly for this purpose.They provide an abstract view of the system by identifying the main actors using it and the main functions that the system provides to them.In the context of agent-based systems,UML use case dia-grams are extended by a special kind of actor (with square heads)representing agents.Goal cases (shown as clouds)are used in order to specify the goals of agents (cf.[12]).

The use case diagram of Figure 1,for example,identi?es,besides two kinds of users,the agents PBA and AccountAgent .In this way,additional architectural requirements about the distribution of the system’s functionality over different agents can be ex-pressed.The use cases select account and pay bill that these agents participate in are internal to the system.They would not be shown in a typical UML use case diagram.

The abstract narrative description given by use cases is illustrated by typical ex-amples,called scenarios ,of how the system behaves when a use case is performed.In the methodology of this paper,scenarios are speci?ed in two complementary ways.The overall effect of a use case like select account is described by a pair of instance diagrams as shown in Figure 2modeling a before-after scenario of the use case.In the following section,this pair of diagrams shall be formally interpreted as an individual graph transformation representing the state change of objects and agents in the system.

Fig.2.Global graph transformation rule

In order to specify the communication between actors participating in a use case,UML sequence diagrams are used.The interaction that is necessary to select an account offering minimal transaction cost would typically be realized by the contract net pro-tocol [9,19]which describes the negotiation between a manager and a set of potential contractors about the delegation of a task.In terms of our example,a simpli?ed version of this protocol may be informally described as follows.

The Personal Banking Agent solicits proposals from the Account Agent by is-suing a call for proposals,which speci?es the interest in an account’s transaction costs.Account Agent receiving the call for proposals are viewed as potential contractors,and are able to generate proposals to perform the task.Alternatively,account agents may refuse to propose.Once the Personal Banking Agent receives back replies from the Account Agent ,it evaluates the proposals and makes its choice of which Account Agent will perform the task.The agent of the selected proposal will be sent an accep-tance message,the others will receive a notice of rejection.

A typical scenario for two AccountAgent s is depicted in Figure 3.Other scenarios for our example would include the possibility that no Account Agent makes a proposal or that no proposal is accepted.

A : PBA

Acc2 : AccountAgent cfp(A, B)propose(Acc2, P)

propose(Acc1, P)

accept(A, P)

cfp(A, B)Acc1 : AccountAgent

reject(A, P)

initPayment(B)

Fig.3.Scenario for the banking example

4Analysis

In order to serve as a basis for future design decisions,the requirements are analyzed and re?ned.Implementation-related issues are still avoided.Similar to object-oriented analysis,the re?ned model is structured into (sub)models [18],a structural model ,a dynamic model and a functional model .

As structural model ,an agent class diagram speci?es the types of objects and agents,their attributes,associations,and messages.Notationally,we build on class di-

Fig.4.Class diagram for banking example

agrams in UML [16]where agent classes are represented as active classes (with bold borders)that have an extra compartment for messages.In the agent class diagram in

Figure4we have agent classes PBA and AccountAgent and object classes Bill,Ac-count and Proposal.Associations connect the PBA s to the Bill s they have to pay and AccountAgent s to the Account s they manage.A Bill speci?es an amount to be paid and the Account it is to be paid to.The messages correspond to those in the sequence diagram in Figure3.They are modeled in the special message compartment of the agent class.

The functional model speci?es the overall effect of a use case on the state of the system.In Section3this has been illustrated by a graph transformation,i.e.,a pair of graphs modeling a before-after scenario of the use case.Formally,this scenario can be seen as an individual test case which has to be demonstrated by the implementation of the system.However,in order to have a complete view of the use case’s overall effect, many such graph transformation pairs would be needed.Thus,a mechanism is required to specify(rather than to enumerate)pairs of graphs.The theory of graph transformation

b: Bill

b: Bill

Fig.5.Three rules specifying the possible result of each interaction

suggests a rule-based approach to this problem.A graph transformation rule L→R consists of a pair of graphs L,R such that the union L∪R is de?ned.(This ensures that,e.g.,edges which appear in both L and R are connected to the same vertices in both graphs.)The left-hand side L represents the preconditions of the rule while the right-hand side R describes the postconditions.During analysis,rules are considered as incomplete speci?cations of the transformations to be performed,i.e.,additional(un-speci?ed)changes are permitted.This(quite liberal)notion of graph transition[8]shall be strengthened in the design model by the notion of graph transformation which as-sumes a complete speci?cation of the changes during a step.

Figure5shows three rules specifying the possible effects of the use case select account.Each rule is only concerned with the interaction of one PBA with one of its AccountAgent s during the execution of the contract net protocol.They specify the three possible results of each binary interaction.

The dynamic model complements the functional model by focusing on the commu-nication required to execute a certain protocol.Like in the requirements speci?cation,

we use sequence diagrams to model the message?ow between agents in the system. However,during analysis,we strengthen the semantics of these diagrams from an exis-tential to a universal interpretation.This is analogous to the shift from individual trans-formations to universal transformation rules in the functional model.Thus,a sequence diagram associated with a graph transformation rule provides a complete speci?cation of the interactions to be performed when the precondition is met.In Figure6,the se-

a:PBA acc:AccountAgent

cfp(a, b)

propose(acc, p)

accept(a, p)

a:PBA acc:AccountAgent

cfp(a, b)

propose(acc, p)

reject(a, p)

a:PBA acc:AccountAgent

cfp(a, b)

initPymt(b)initPymt(b)

initP.(b)

Fig.6.Three sequence diagrams corresponding to the three rules in Figure5 quence diagrams for the banking example are presented.The?rst diagram models the case that the proposal of the AccountAgent is accepted by the PBA and the second one the rejection of the proposal.The third diagram depicts the case that the Accoun-tAgent does not answer upon a call for proposal.They correspond to the three rules in Figure5.A sequence diagram is activated when the precondition of the corresponding rule is met.For the rules in Figure5associated with the sequence diagrams in Figure6, the precondition requires that the Account Agent is connected with the PBA by a uses link,and that the latter is activated by an initPayment message.Since the precondition is the same in all three cases,if the condition is met,the interaction between the two agents may conform to one of the three sequence diagrams.

5Design

The analysis phase is concerned with developing a model of what the system is sup-posed to do.The design model elaborates the analysis model concentrating on the ques-tion how the system will function.As a consequence,the focus of models is shifted from a global view on the system during analysis to a local view,thus providing the basis for an implementation.Like in analysis,we distinguish a structural model,a dynamic model,and a functional model.

In the structural model,the class diagram of the design phase re?nes the class di-agram of the analysis adding,in particular,the signatures of the agent’s autonomous operations for which an extra compartment is provided.Notice the difference with

Fig.7.Agent class diagram

methods as speci?ed in the method compartment of objects:agent’s operations are au-tonomous,that is,they are never called by another object or agent but only executed un-der control of the agent itself(cf.Section2).As a consequence,we distinguish agent’s messages and operations while in the case of objects,both notions are integrated in the notion of a method.

By a state diagram for each agent class,the dynamic model speci?es the ordering of operations an agent of this class may perform.As agents do not automatically react to events of their environment but decide autonomously when and how to react,transitions are not labeled with an event and an action but only with the name of the operation. This usage of statecharts is semantically different from traditional approaches[11].The notion of a protocol state machine[16]comes closest to our understanding.Consider, as an example,the statechart for the AccountAgent.From the?rst state,this agent may either proceed to the proposed state by answering a call for proposal or it may decide not to propose and proceed to the?nal state.The agent decides what to do based on an internal strategy that is not part of the model.

In the functional model,the operations declared in the structural model are speci-?ed by graph transformation rules.Whereas the dynamic model is concerned with the order of operations,the functional model shows how operations change the state of the system.As agent’s operations may only affect that part of the state which can be ac-cessed locally,we require that all objects in the left-hand side of a rule are reachable via a path originating at the self agent.For example,in Figure9the operations getBill and sendCFP of the PBA are speci?ed.The?rst operation triggers the agent to issue requests for proposals for a given bill.If a PBA has not yet sent a call to a particular AccountAgent(expressed by the negative context condition for the sent link)the PBA

acc.answerCFP(b)

Fig.8.Statecharts for agents PBA and AccountAgent

b : Bill

a : PBA

initPayment(b)

Fig.9.Graph transformation rules getBill and sendCFP

may use the second rule for issuing the call.On reception of a call for proposal mes-

Fig.10.Graph transformation rule answerCFP

sage,an AccountAgent may decide to send a Proposal specifying the

costs for the

required transaction as described by the rule answerCFP in Figure10.The alternative

rule for ignoreProp is not shown.It has the same pre-condition and the

only effect

of removing the cfp message.Receiving a proposal,the PBA may either reject it if it

Fig.11.Graph transformation rule stopCFP

has bigger cost than the best proposal received so far or it may record this proposal as its current favorite.The?rst proposal is recorded when the agent stops sending calls. The operations stopCFP and recordProp are speci?ed in Figure11and12.The rule for rejectProp is not shown.When the PBA decides to have received enough propos-als,it sends the current best an accept message.Upon reception of this message,the AccountAgent records its proposal as accepted.When rejected,the agent deletes its proposal.

6Roles in Agent-Oriented Modeling

The concept of roles is well-established in object-oriented modeling[13].During its life-time,an object may play one or several roles encapsulating a certain functionality which may change dynamically when the object evolves.The operations and attributes required to play a role are represented by a role type.The existence of an object’s role

c < c‘Fig.12.Graph transformation rule recordProp

Fig.13.Graph transformation rule acceptProp

depends on that of the object itself.Roles restrict the visibility of an object or agent if associations to other objects or agents only exist via attached roles.

In agent-oriented modeling,agent roles are used for capturing goals,tasks,or func-tions exhibited by the agent.According to Wooldridge et al.[21],a role has associated to it responsibilities,permissions,activities,and protocols which are de?ned by speci?c role schemata.Responsibilities comprise lifeness conditions like the execution of a pre-scribed sequence of protocols.In this way the interaction of roles is speci?ed.Wood et al.[20]introduce a Multi-agent Systems Engineering(MaSE)methodology where roles are introduced as more?ne-grained building blocks of agent classes which cap-ture agent goals during the design phase.A role serves as an abstract description for the functions it is responsible to ful?ll in order to reach an assigned goal.

Both object and agent roles restrict the behavior and state of an entity to the part which is necessary to reach a goal,to ful?ll a single task,or to participate in a speci?c interaction.Next,we sketch in which way roles would be integrated in our methodol-ogy.In the requirements speci?cation,an actor’s interactions are determined by the use cases it is participating in.Each interactions de?nes a role of the actor,encapsulating the agent’s behavior during the corresponding use case.The personal banking agent,for example,assumes the role of an account selector when interacting with the select ac-count use case in Figure1.Relative to this use case,the account agent takes the role of a possible contractor for the selection of an account.Another role of the account agent is that of a bill payer transferring money to another account.When global graph trans-formation rules and sequence diagrams are used to describe the functional behavior of use cases,each occurrence of an agent in a rule or a diagram corresponds to a different role.

Thus,in the early stage of development,roles simplify the transition from require-ment speci?cation to analysis.In fact,the classes in the analysis model can be derived by integrating role classes that encapsulate the state and behavior necessary to partic-ipate in the interactions associated with the use cases.Role classes can be instantiated like object or agent classes,but their instances do only exist in connection with an agent or object.That means,a role instance automatically disappears together with the object, agent or role it depends on.Thus,from a structural point of view,this role-of relation-ship is similar to a composition in UML.Considering the behavior of roles,it resembles inheritance because roles can access their parent’s features as if they were their own.

Roles also make more systematic the transition from analysis to design because each role contributes only to one global interaction.Thus,interactions can be realized one by one.In a second step,the behavior of the corresponding roles can be coordinated yield-ing the behavior of the entire class.In this way the complexity of the total behavior of a class participating in many different interactions can be structured,e.g.,by attaching statecharts to the individual roles and synchronizing theses statecharts afterwards.

In order to make this concept of roles more useful it has to be integrated syntactically and semantically in a formal agent model like the one presented in[4].

7Conclusion

In this paper,we have presented an approach to agent-oriented modeling based on UML notation and concepts of typed graph transformation systems[2].Extending the no-tion of active object from object-oriented modeling,speci?c support is provided for characteristic aspects of agent-based systems like autonomy,goal-driven behavior,and cooperation of agents.

The theory of graph transformation also provides the mathematical background for the formalization of the approach.In[4],for example,graph processes[2]and con-cepts of views of graph transformation systems[8]are used in order to formalize the consistency between requirement speci?cation,analysis and design in agent-oriented modeling.

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Windows系统自带画图工具教程87586

1.如何使用画图工具 想在电脑上画画吗?很简单,Windows 已经给你设计了一个简洁好用的画图工具,它在开始菜单的程序项里的附件中,名字就叫做“画图”。 启动它后,屏幕右边的这一大块白色就是你的画布了。左边是工具箱,下面是颜色板。 现在的画布已经超过了屏幕的可显示范围,如果你觉得它太大了,那么可以用鼠标拖曳角落的小方块,就可以改变大小了。 首先在工具箱中选中铅笔,然后在画布上拖曳鼠标,就可以画出线条了,还可以在颜色板上选择其它颜色画图,鼠标左键选择的是前景色,右键选择的是背景色,在画图的时候,左键拖曳画出的就是前景色,右键画的是背景色。

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方案二:四等分三角形的任意一边,由等底等高的三角 形面积相等,可以得出四部分面积相等,如图1-1.3。 图1-1.3 用几何画板验证: 第一步:打开几何画板程序,这时出现一个新绘图文件。 说明:如果几何画板程序已经打开,只要由菜单“文件” “新绘图”,也可以新建一个绘图文件。第二步:(1)在工具箱中选取“画线段”工具; (2)在工作区中按住鼠标左键拖动,画出一条线段。如图 1-1.4。 注意:在几何画板中,点用一个空心的圈表示。 图1-1.4 第三步:(1)选取“文本”工具;(2)在画好的点上单击左 键,可以标出两点的标签,如图1-1.5: 注意:如果再点一次,又可以隐藏标签,如果想改标签 为其它字母,可以这样做: 用“文本”工具双击显示的标签,在弹出的对话框中进 行修改,(本例中我们不做修改)。如图1-1.6 图1-1.6 在后面的操作中,请观察图形,根据需要标出点或线的 标签,不再一一说明 B 图1-1.5 第四步:(1)再次选取“画线段”工具,移动鼠标与点A 重合,按左键拖动画出线段AC;(2)画线段BC,标出标 签C,如图1-1.7。 注意:在熟悉后,可以先画好首尾相接的三条线段后再 标上标签更方便。 B 图1-1.7

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认识画图软件教案

《认识画图软件》教学设计 任教教师:苗丽娟 所在学校:复兴小学

《认识画图软件》教学设计 教学目标: 1、能熟练启动并退出画图软件; 2、认识画图软件的窗口并了解各种绘画工具的使用; 3、能绘制简单的图形。 重点难点: 了解各种绘画工具的使用。 教学时间:一课时 课前准备: 课件 教学过程: 一、导入 1、今天的天气真好,阳光明媚,老师和大家一起来欣赏一些作品(出示课件) 师:这些画漂不漂亮,它们不仅漂亮而且还很神奇。因为不是用笔和纸画出来的,而是用电脑上的画图软件画出来的。同学们想不想成为一名电脑绘画小高手。那就和老师一起来学习这一课:认识画图软件(课件出示) 二、新授 1、启动画图软件: 课件出示启动画图软件的方法,请同学们根据课件演示操作。 2、认识画图软件窗口: 课件出示画图软件窗口。 3、认识工具箱 (1)师问:工具箱中有多少个按钮? 师:告诉大家一个方法,当我们把鼠标指针放到某个工具上时就会在它的旁边出现它的名字,而且下面任务栏中会出现对这个工具使用方法的介绍。 现在就请大家发挥你的小组合作能力,自主的探究一下这些工具: (2)课件出示:合作探究:工具箱中的各种工具有些什么作用?怎样使用?

(3)师说明活动要求:两人为一个小组进行合作,解决上述问题。 (4)学生操作。师和学生单独交流,了解学生学习情况,收集学生问题。(5)师问:谁愿意说说你对哪个工具最了解?它的名称是什么?怎样使用?(学生边说边演示,鼓励台下学生向台上演示的学生提出不懂的问题并寻求解决方法) 4、认识调色板: 课件出示选色框图:上面框中的颜色称为前景色,下面框中的颜色称为背景色 我们已经简单的认识了一些工具,现在我们画一个简单的图形并给它涂上颜色。 生画完后,师:在刚才的上色过程中为什么只有前景色会变化?背景色怎样改变?大家尝试一下。 师总结:单击左键拾取前景色,单击右键拾取背景色。 课件出示儿歌: 调色板儿真方便,多种颜色我来选。 单击左键前景色,单击右键背景色。 前景背景不一样,两键单击记心间。 三、退出画图软件 师:当图软件用完之后,怎样退出呢?聪明的你们能不能从课本上找到答案?有几种方法? 第一种: 单击“文件(F)”菜单中的“退出(X)”命令,可以退出“画图”程序。 第二种:按一下右上角的× 师:如果还没有保存画好或修改过的图形,则在退出“画图”程序时,屏幕上会出现“画图”对话框,这时,如果单击“是(Y)”按钮,则保存图形后再退出;如果单击“否(N)”按钮,则不保存图形就退出;如果单击“取消”按钮,则不退出“画图”程序。 四、赛一赛

pymol作图的一个实例演示教学

p y m o l作图的一个实 例

Pymol作图的实例 这是一个只是用鼠标操作的初步教程 Pdb文件3ODU.pdb 打开文件 pymol右侧 All指所有的对象,2ODU指刚才打开的文件,(sele)是选择的对象 按钮A:代表对这个对象的各种action, S:显示这个对象的某种样式, H:隐藏某种样式, L:显示某种label, C:显示的颜色 下面是操作过程: 点击all中的H,选择everything,隐藏所有 点击3ODU中的S,选择cartoon,以cartoon形式显示蛋白质 点击3ODU中的C,选择by ss,以二级结构分配颜色,选择 点击右下角的S,窗口上面出现蛋白质氨基酸序列,找到1164位ITD,是配体点击选择ITD ,此时sele中就包含ITD这个残基,点击(sele)行的A,选择rename selection,窗口中出现

,更改sele为IDT,点击(IDT)行的S选择sticks,点击C,选择by element,选择,,调整窗口使此分子清楚显示。 寻找IDT与蛋白质相互作用的氢键: IDT行点击A 选择find,选择polar contacts,再根据需要选择,这里选择to other atoms in object ,分子显示窗口中出现几个黄色的虚线 ,IDT行下面出现了新的一行 ,这就是氢键的对象,点击这一行的C,选择red red,把氢键显示为红色。 接着再显示跟IDT形成氢键的残基 点击3ODU行的S,选择lines,显示出所有残基的侧链,使用鼠标转动蛋白质寻找与IDT以红色虚线相连的残基,分别点击选择这些残基。注意此时selecting要是residures。选择的时候要细心。取消选择可以再次点击已选择的残基。使用上述的方法把选择的残基(sele)改名为s1。点击S1行的S选择sticks,C选择by elements,点击L选择residures显示出残基名称.在这个例子中发现其中有一个N含有3个氢键有两个可以找到与其连接的氨基酸残基,另一个找不到,这是因为这个氢键可能是与水分子形成的,水分子在pdb文件中只用一个O表示,sticks显示方式没有显示出来水分子,点击all行S选择nonbonded,此时就看到一个水与N形成氢键

使用画图工具

如何使用画图工具 想在电脑上画画吗?很简单,Windows 已经给你设计了一个简洁好用的画图工具,它在开始菜单的程序项里的附件中,名字就叫做 “画图”。 启动它后,屏幕右边的这一大块白色就是你的画布了。左边是 工具箱,下面是颜色板。 现在的画布已经超过了屏幕的可显示范围,如果你觉得它太大了,那么可以用鼠标拖曳角落的小方块,就可以改变大小了。 首先在工具箱中选中铅笔,然后在画布上拖曳鼠标,就可以画出线条了,还可以在颜色板上选择其它颜色画图,鼠标左键选择的是

前景色,右键选择的是背景色,在画图的时候,左键拖曳画出的就是前 景色,右键画的是背景色。 选择刷子工具,它不像铅笔只有一种粗细,而是可以选择笔尖的大小和形状,在这里单击任意一种笔尖,画出的线条就和原来不一 样了。 图画错了就需要修改,这时可以使用橡皮工具。橡皮工具选定后,可以用左键或右键进行擦除,这两种擦除方法适用于不同的情况。左键擦除是把画面上的图像擦除,并用背景色填充经过的区域。试验一下就知道了,我们先用蓝色画上一些线条,再用红色画一些,然后选择橡皮,让前景色是黑色,背景色是白色,然后在线条上用左键拖曳,可以看见经过的区域变成了白色。现在把背景色变成绿色,再用左键擦除,可以看到擦过的区域变成绿色了。 现在我们看看右键擦除:将前景色变成蓝色,背景色还是绿色,在画面的蓝色线条和红色线条上用鼠标右键拖曳,可以看见蓝色的线条被替换成了绿色,而红色线条没有变化。这表示,右键擦除可以只擦除指定的颜色--就是所选定的前景色,而对其它的颜色没有影响。 这就是橡皮的分色擦除功能。 再来看看其它画图工具。 是“用颜料填充”,就是把一个封闭区域内都填上颜色。 是喷枪,它画出的是一些烟雾状的细点,可以用来画云或烟 等。

CAD绘图教程及案例_很实用

CAD 绘制三维实体基础 AutoCAD除具有强大的二维绘图功能外,还具备基本的三维造型能力。若物体并无复杂的外表曲面及多变的空间结构关系,则使用AutoCAD可以很方便地建立物体的三维模型。本章我们将介绍AutoCAD 三维绘图的基本知识。 11.1 三维几何模型分类 在AutoCAD中,用户可以创建3种类型的三维模型:线框模型、表面模型及实体模型。这3种模型在计算机上的显示方式是相同的,即以线架结构显示出来,但用户可用特定命令使表面模型及实体模型的真实性表现出来。 11.1.1线框模型(Wireframe Model) 线框模型是一种轮廓模型,它是用线(3D空间的直线及曲线)表达三维立体,不包含面及体的信息。不能使该模型消隐或着色。又由于其不含有体的数据,用户也不能得到对象的质量、重心、体积、惯性矩等物理特性,不能进行布尔运算。图11-1显示了立体的线框模型,在消隐模式下也看到后面的线。但线框模型结构简单,易于绘制。 11.1.2 表面模型(Surface Model) 表面模型是用物体的表面表示物体。表面模型具有面及三维立体边界信息。表面不透明,能遮挡光线,因而表面模型可以被渲染及消隐。对于计算机辅助加工,用户还可以根据零件的表面模型形成完整的加工信息。但是不能进行布尔运算。如图11-2所示是两个表面模型的消隐效果,前面的薄片圆筒遮住了后面长方体的一部分。 11.1.3 实体模型 实体模型具有线、表面、体的全部信息。对于此类模型,可以区分对象的内部及外部,可以对它进行打孔、切槽和添加材料等布尔运算,对实体装配进行干涉检查,分析模型的质量特性,如质心、体积和惯性矩。对于计算机辅助加工,用户还可利用实体模型的数据生成数控加工代码,进行数控刀具轨迹仿真加工等。如图11-3所示是实体模型。 图11-1 线框模型 图11-2 表面模型 1、三维模型的分类及三维坐标系; 2、三维图形的观察方法; 3、创建基本三维实体; 4、由二维对象生成三维实体; 5、编辑实体、实体的面和边;

《画图软件画图忙》教学设计

《画图软件画图忙》教学设计 [教学目标] (1)学习启动与退出“画图”程序。 (2)了解“画图”窗口的组成,特别是画图窗口独特的组成部分。 (3)学生通过自主探索初步认识绘图工具箱。 (4)通过对画图作品的欣赏和对画图程序的简单操作,培养学生对电脑画图的兴趣,从而进一步培养对信息技术的热爱。 [教学重点与难点] 重点:培养良好的画图习惯,能正确使用撤消和擦除。 难点:读懂对话框,学会保存作品。 [课时安排] 1课时。 [教学准备] 多媒体网络教室、多媒体课件 [教学过程] 一、激趣导入 师:今天,老师给大家带来了一位美术高手,但他不用纸笔,而是用电脑画画,想不想看他的精彩表演? 播放《用“画图”画跑车》视频(2分钟)。

师:这位高手厉害不厉害?我们班有没有人能做到?想不想学? 师:想成为高手可不是一朝一夕的事儿,我们要一点一滴地学习。首先,需要有敏锐的观察力。所以,我要考考大家,刚才视频中的高手是用哪个软件完成这幅图画的? 师:看!这就是windows操作系统自带的“画图”程序。今天我们就来认识这个新朋友——“画图”。(板书课题) 二、教学新课 (一)启动“画图” 1.大家想认识这位新朋友吗?请你到电脑里把它找出来。 2.交流:你是如何找到这位新朋友的? 3.是啊,联系以前学过的打开“写字板”的方法,同学们很快就找到了,这种知识迁移的方法是我们学习新知识的一种重要的方法。 (二)“画图”窗口 1.同学们都成功的启动了画图,看看这位新朋友,结合写字板,它窗口的哪些组成部分你认识呢? 2.教师结合“写字板”引导小结。 常规部分:标题栏、菜单栏、状态栏 独特组成:工具箱、颜料盒、画图区 3.画图窗口中画图区就是我们用来画画的纸,我觉得这张纸太小了,你能帮我变大些吗?

50款医学软件

一、PPT模板与软件: 1.ScienceSlides: ScienceSlides是一种PPT插件,可方便的画出各种细胞器化学结构,用来论文画图确实很好用。特别是用这个和AI(illustrator)结合,画的图可以媲美老外的CNS哦。 2.科研医学美图PPT模板 3.200+套绝美PPT模板 二、代谢与信号分析软件: 1.CellNetAnalyzer: CellNetAnalyzer,是一种细胞网络分析工具,前身是FluxAnalyzer,是基于MatLab的代谢网络和信号传导网络分析模块,。这是一个典型的代谢流分析工具,可以进行代谢流的计算、预测、目标函数的优化,端途径分析、元素模式分析,以及代谢流之间的对比等。可以基本满足研究一个中型代谢网络的结构尤其是计算流分配的要求,大部分论文中的代谢网络分析都是或明或暗的用这个分析的。

2. 信号通路图汇总 3. 药理学思维导图 三、二维、三维构图软件: 1.DeepViewer _4.10_PC DeepViewer ,曾经也叫做Swiss-PdbViewer,是一个可以同时分析几个蛋白的应用程序。为了结构比对并且比较活性位点或者任何别的相关部分,蛋白质被分成几个层次。氨基酸突变,氢键,原子间的角和距离在直观的图示和菜单界面上很容易获得。 2.pymol-0_99rc6-bin-win32 PyMOL是一个开放源码,由使用者赞助的分子三维结构显示软件。PyMOL适用于创作高品质的小分子或是生物大分子(特别是蛋白质)的三维结构图像。PyMOL的源代码目前仍可以免费下载,供使用者编译。对于Linux、Unix以及Mac OS X等操作系统,非付费用户可以通过自行编译源代码来获得PyMOL执行程式;而对于Windows的使用者,如果不安装第三方软件,则无法编译源代码。 四、分子生物学软件

Matlab绘图教程(大量实例PPT)

MATLAB绘图

二维数据曲线图 p plot函数的基本调用格式为: x,y) ) plot( plot(x,y 其中x和y为长度相同的向量,分别用于存储x坐标和y坐标数据。 数据 例1 在0≤x2π区间内,绘制曲线y=2e-0.5x cos(4πx) 1≤区间内绘制曲线205x(4) 程序如下: x=0:pi/100:2*pi; cos(4*pi*x); 0.5*x).*cos (4*pi*x); y=2*exp(--0.5*x).* y=2*exp( x,y)) plot(x,y plot(x y plot( x y)

例2 绘制曲线。 绘制曲线 程序如下: t=0:0.1:2*pi; x=t.sin(3t); x=t*sin(3*t); y=t.*sin(t).*sin(t); plot( x,y);); plot(x,y

数最简单的调用格式是包含个输参数plot函数最简单的调用格式是只包含一个输入参数:p() plot(x) 在这种情况下,当x是实向量时,以该向量元素的下标为横坐标,元素值为纵坐标画出条连续曲线,标为横坐标,元素值为纵坐标画出一条连续曲线,这实际上是绘制折线图。

绘制多根二维曲线 1.plot函数的输入参数是矩阵形式时 数的输参数是矩阵形式时 (1) 当x是向量,y是有一维与x同维的矩阵时,则绘制出多根不同颜色的曲线。曲线条数等于y矩阵的另一维数,x被作为这些曲线共同的横坐标。 (2) 当x,y是同维矩阵时,则以x,y对应列元素为横、 纵坐标分别绘制曲线,曲线条数等于矩阵的列数。纵坐标分别绘制曲线曲线条数等于矩阵的列数

蛋白质作图软件pymol教程 Pymol学习笔记

B2WS-6JGH-PV7G-PBKP 什么是结构生物学 结构生物学(Structural biology)是生物领域里面相对较新的一个分支。它主要以生物化学和生物物理学方法来研究生物大分子,特别是蛋白质和核酸,的三维结构,以及与结构相对应的功能。因为几乎所有的细胞内的生命活动都是通过生物大分子来完成的,并且这些大分子完成这些功能的前提是它们必须具有特定的三维结构,因此,对于生物化学家们,这是一个非常具有吸引力的领域。 该领域通常被认为开始于20世纪50年代,Max Perutzhe和Sir John Cowdery Kendrew于1959年各自利用X射线晶体学方法解析了肌红蛋白(Myoglobin)的三维结构,一种在肌肉中运输氧气的蛋白。他们因此分享了1962年的诺贝尔化学奖,并由此揭开了结构生物学的序幕。截止到2008年10月28日,已有53917个生物大分子结构在https://www.doczj.com/doc/f818207696.html, (蛋白质数据库)登记在案。 目前用于研究生物大分子结构的常用方法有X射线晶体学(X-ray crystallography)、核磁共振(NMR)、电子显微学(electron microscopy)、冷冻电子显微学(electron cryomicroscopy = cryo-EM)、超快激光光谱(ultra fast laser spectroscopy)、双偏振极化干涉(Dual Polarisation Interferometry)以及圆二色谱(circular dichroism)等。当中又以X射线晶体学和核磁共振最为常用。 图一:肌红蛋白(Myoglobin)的三维结构,世界上第一个由X射线晶体学解出的蛋白质结构,该蛋白在肌肉中传输氧气。

GRADS绘图实例教程

500mb高度场等直线图 .gs文件 * * Draw the COR.COEF SST and nhc000 * 'reinit' 'enable print h9601.31' 'clear' 'open hs.ctl' 'set dfile 1' 'set vpage 0.5 10. 0.2 8.5' 'set lon 0. 360.' 'set lat -90. 90.' 'set mproj latlon' 'set mpdset mres' 'set poli off' 'set ylint 10.' 'set xlint 20.' 'set csmooth on' 'set csmooth on' 'set csmooth on' 'set csmooth on' 'set csmooth on' 'set csmooth on' 'set csmooth on' 'set csmooth on' 'set clopts -1 -1 0.06' 'set clab forced' 'set cint 40.' 'set gxout contour' 'set cthick 4' 'set grads off' 'd rsst55' 'set string 3 c 5 0' 'set strsiz 0.14' 'draw string 4.5 7.5 1996.1.31 Global 500mb Geopotential Height Field' 'print' pull dummy .ctl文件 DSET h9601.31a TITLE height FORMAT yrev UNDEF -9999.00

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