To overcome inefficiency in traditional logic programming, a declarative programming language COPS is designed based on the notion of concurrent constraint programming (CCP). The improvement is achieved by the adoptio...To overcome inefficiency in traditional logic programming, a declarative programming language COPS is designed based on the notion of concurrent constraint programming (CCP). The improvement is achieved by the adoption of constraint-based heuristic strategy and the introduction of deterministic components in the framework of CCP. Syntax specification and an operational semantic description are presented.展开更多
LP (Logic Programming) has been successfully applied to knowledge discovery in many fields. The execution of the LP is based on the evaluation of the first order predicate. Usually the information involved in the pred...LP (Logic Programming) has been successfully applied to knowledge discovery in many fields. The execution of the LP is based on the evaluation of the first order predicate. Usually the information involved in the predicates are local and homogenous, thus the evaluation process is relatively simple. However, the evaluation process become much more complicated when applied to KDD on the Internet where the information involved in the predicates maybe heterogeneous and distributed over many different sits. Therefor, we try to attack the problem in a multi agent system's framework so that the logic program can be written in a site independent style and deal easily with heterogeneous represented information.展开更多
Code defects can lead to software vulnerability and even produce vulnerability risks.Existing research shows that the code detection technology with text analysis can judge whether object-oriented code files are defec...Code defects can lead to software vulnerability and even produce vulnerability risks.Existing research shows that the code detection technology with text analysis can judge whether object-oriented code files are defective to some extent.However,these detection techniques are mainly based on text features and have weak detection capabilities across programs.Compared with the uncertainty of the code and text caused by the developer’s personalization,the programming language has a stricter logical specification,which reflects the rules and requirements of the language itself and the developer’s potential way of thinking.This article replaces text analysis with programming logic modeling,breaks through the limitation of code text analysis solely relying on the probability of sentence/word occurrence in the code,and proposes an object-oriented language programming logic construction method based on method constraint relationships,selecting features through hypothesis testing ideas,and construct support vector machine classifier to detect class files with defects and reduce the impact of personalized programming on detection methods.In the experiment,some representative Android applications were selected to test and compare the proposed methods.In terms of the accuracy of code defect detection,through cross validation,the proposed method and the existing leading methods all reach an average of more than 90%.In the aspect of cross program detection,the method proposed in this paper is superior to the other two leading methods in accuracy,recall and F1 value.展开更多
Humans are experiencing the inclusion of artificial agents in their lives,such as unmanned vehicles,service robots,voice assistants,and intelligent medical care.If the artificial agents cannot align with social values...Humans are experiencing the inclusion of artificial agents in their lives,such as unmanned vehicles,service robots,voice assistants,and intelligent medical care.If the artificial agents cannot align with social values or make ethical decisions,they may not meet the expectations of humans.Traditionally,an ethical decision-making framework is constructed by rule-based or statistical approaches.In this paper,we propose an ethical decision-making framework based on incremental ILP(Inductive Logic Programming),which can overcome the brittleness of rule-based approaches and little interpretability of statistical approaches.As the current incremental ILP makes it difficult to solve conflicts,we propose a novel ethical decision-making framework considering conflicts in this paper,which adopts our proposed incremental ILP system.The framework consists of two processes:the learning process and the deduction process.The first process records bottom clauses with their score functions and learns rules guided by the entailment and the score function.The second process obtains an ethical decision based on the rules.In an ethical scenario about chatbots for teenagers’mental health,we verify that our framework can learn ethical rules and make ethical decisions.Besides,we extract incremental ILP from the framework and compare it with the state-of-the-art ILP systems based on ASP(Answer Set Programming)focusing on conflict resolution.The results of comparisons show that our proposed system can generate better-quality rules than most other systems.展开更多
Due to the emergence of a large number of counterfeit notes and incomplete coins in the slot machine of self-service bus, to improve the automization of intelligent slot machine, based on multi-sensor testing technolo...Due to the emergence of a large number of counterfeit notes and incomplete coins in the slot machine of self-service bus, to improve the automization of intelligent slot machine, based on multi-sensor testing technology, using programming log- ic controller (PLC) as the core of the whole system, the PLC hardware design and software design are accomplished for the first time to detect the counterfeit notes and coins. The system was tested by many groups of experiments. The results show that the system has reliable recognition rate, good flexibility and stability, reaching the accuracy of 97%.展开更多
First, the concept of cooperative conflict is presented, and the characteristic of cooperative air combat is researched. Then, four methods of conflict resolution are designed by way of the first order predicate logic...First, the concept of cooperative conflict is presented, and the characteristic of cooperative air combat is researched. Then, four methods of conflict resolution are designed by way of the first order predicate logic, i.e., link-up, coordination, accommodation and integration, and corresponding examples are given. A 2 vs 2 air combat simulation was carried out; after conflict resolution, the loss ratio is dropped to 0.54 from the original 1.32, so the enhancement of effectiveness is notable. The present research findings are that the wide conflicts discover the essence of multi-fighter cooperation, i.e., to as fully as possible enhance the effectiveness of each fighter to attain global optimization, and that the possibility of conflict resolution shows the application prospect. The proposed method in this paper is a helpful try to the application of the Fifth Generation Computer in the new generation of C3I system.展开更多
Based on logic programs, authorization conflicts and resolution strategies are analyzed through the explanation of some examples on the health care sector. A resolution scheme for handling conflicts in high level auth...Based on logic programs, authorization conflicts and resolution strategies are analyzed through the explanation of some examples on the health care sector. A resolution scheme for handling conflicts in high level authorization specification by using logic program with ordered disjunction (LPOD) is proposed. The scheme is useful for solving conflicts resulted from combining positive and negative authorization, complexity of authorization management, and less clarity of the specification. It can well specify kinds of conflicts (such as exceptional conflicts, potential conflicts), and is based on literals and dependent contexts. Thus it is expressive and available. It is shown that authorizations based on rules LPOD is very important both in theory and practice.展开更多
We describe a system called CFLP which aims at the integration of the best features of functional logic programming (FLP), cooperative constraint solving (CCS), and distributed computing. FLP provides support for defi...We describe a system called CFLP which aims at the integration of the best features of functional logic programming (FLP), cooperative constraint solving (CCS), and distributed computing. FLP provides support for defining one's own abstractions over a constraint domain in an easy and comfortable way, whereas CCS is employed to solve systems of mixed constraints by iterating specialized constraint solving methods in accordance with a well defined strategy. The system is a distributed implementation of a cooperative constraint functional logic programming scheme that combines higher order lazy narrowing with cooperative constraint solving. The model takes advantage of the existence of several constraint solving resources located in a distributed environment (e.g., a network of computers), which communicate asynchronously via message passing. To increase the openness of the system, we are redesigning CFLP based on CORBA. We discuss some design and implementation issues of the system.展开更多
Radial Basis Function Neural Network(RBFNN)ensembles have long suffered from non-efficient training,where incorrect parameter settings can be computationally disastrous.This paper examines different evolutionary algor...Radial Basis Function Neural Network(RBFNN)ensembles have long suffered from non-efficient training,where incorrect parameter settings can be computationally disastrous.This paper examines different evolutionary algorithms for training the Symbolic Radial Basis Function Neural Network(SRBFNN)through the behavior’s integration of satisfiability programming.Inspired by evolutionary algorithms,which can iteratively find the nearoptimal solution,different Evolutionary Algorithms(EAs)were designed to optimize the producer output weight of the SRBFNN that corresponds to the embedded logic programming 2Satisfiability representation(SRBFNN-2SAT).The SRBFNN’s objective function that corresponds to Satisfiability logic programming can be minimized by different algorithms,including Genetic Algorithm(GA),Evolution Strategy Algorithm(ES),Differential Evolution Algorithm(DE),and Evolutionary Programming Algorithm(EP).Each of these methods is presented in the steps in the flowchart form which can be used for its straightforward implementation in any programming language.With the use of SRBFNN-2SAT,a training method based on these algorithms has been presented,then training has been compared among algorithms,which were applied in Microsoft Visual C++software using multiple metrics of performance,including Mean Absolute Relative Error(MARE),Root Mean Square Error(RMSE),Mean Absolute Percentage Error(MAPE),Mean Bias Error(MBE),Systematic Error(SD),Schwarz Bayesian Criterion(SBC),and Central Process Unit time(CPU time).Based on the results,the EP algorithm achieved a higher training rate and simple structure compared with the rest of the algorithms.It has been confirmed that the EP algorithm is quite effective in training and obtaining the best output weight,accompanied by the slightest iteration error,which minimizes the objective function of SRBFNN-2SAT.展开更多
We discuss the projection temporal logic (PTL), based on a primitiveprojection operator, prj. A framing technique is also presented, using which a synchronizationoperator, await, is defined within the underlying logic...We discuss the projection temporal logic (PTL), based on a primitiveprojection operator, prj. A framing technique is also presented, using which a synchronizationoperator, await, is defined within the underlying logic. A framed temporal logic programminglanguage (FTLL) is presented. To illustrate how to use both the language and framing technique, someexamples are given.展开更多
Currently, agent-based computing is an active research area, and great efforts have been made towards the agent-oriented programming both from a theoretical and practical view. However, most of them assume that there ...Currently, agent-based computing is an active research area, and great efforts have been made towards the agent-oriented programming both from a theoretical and practical view. However, most of them assume that there is no uncertainty in agents' mental state and their environment. In other words, under this assumption agent developers are just allowed to specify how his agent acts when the agent is 100% sure about what is true/false. In this paper, this unrealistic assumption is removed and a new agent-oriented probabilistic logic programming language is proposed, which can deal with uncertain information about the world. The programming language is based on a combination of features of probabilistic logic programming and imperative programming.展开更多
This paper presents a logic-program-based mechanism of negotiation between two agents. In this mechanism an extended logic program (ELP) is regarded as an agent. The negotiation process between two agents is then mo...This paper presents a logic-program-based mechanism of negotiation between two agents. In this mechanism an extended logic program (ELP) is regarded as an agent. The negotiation process between two agents is then modelled as multiple encounters between two ELPs, each of which selects an answer set as its initial demand. Both agents mutually revise the original sets of demands through accepting part of the opponent's demand and/or giving up part of its own demand. The overall dynamics can be regarded as mutual updates between two extended logic programs. A deal to achieve an appropriate negotiation solution is put forward. The conditions of existence and terminability of an appropriate negotiation are given. Properties of a negotiation solution are discussed, including its weak Pareto optimality.展开更多
In this paper, it is shown that stable model semantics, perfect model semantics, and partial stable model semantics of disjunctive logic programs have the same expressive power with respect to the polynomial-time mode...In this paper, it is shown that stable model semantics, perfect model semantics, and partial stable model semantics of disjunctive logic programs have the same expressive power with respect to the polynomial-time model-equivalent reduction. That is, taking perfect model semantics and stable model semantic as an example, any logic program P can be transformed in polynomial time to another logic program P' such that perfect models (resp. stable models) of P i-i correspond to stable models (resp. perfect models) of P', and the correspondence can be computed also in polynomial time. However, the minimal model semantics has weaker expressiveness than other mentioned semantics, otherwise, the polynomial hierarchy would collapse to NP.展开更多
Atomic blocks, a high-level language construct that allows programmers to explicitly specify the atomicity of operations without worrying about the implementations, are a promising approach that simplifies concurrent ...Atomic blocks, a high-level language construct that allows programmers to explicitly specify the atomicity of operations without worrying about the implementations, are a promising approach that simplifies concurrent programming. On the other hand, temporal logic is a successful model in logic programming and concurrency verification, but none of existing temporal programming models supports concurrent programming with atomic blocks yet. In this paper, we propose a temporal programming model (αPTL) which extends the projection temporal logic (PTL) to support concurrent programming with atomic blocks. The novel construct that formulates atomic execution of code blocks, which we call atomic interval formulas, is always interpreted over two consecutive states, with the internal states of the block being abstracted away. We show that the framing mechanism in projection temporal logic also works in the new model, which consequently supports our development of an executive language. The language supports concurrency by introducing a loose interleaving semantics which tracks only the mutual exclusion between atomic blocks. We demonstrate the usage of αPTL by modeling and verifying both the fine-grained and coarse-grained concurrency.展开更多
This paper proposes a sequential model of bar- gaining specifying reasoning processes of an agent be- hind bargaining procedures. We encode agents' background knowledge, demands, and bargaining constraints in logic p...This paper proposes a sequential model of bar- gaining specifying reasoning processes of an agent be- hind bargaining procedures. We encode agents' background knowledge, demands, and bargaining constraints in logic pro- grams and represent bargaining outcomes in answer sets. We assume that in each bargaining situation, each agent has a set of goals to achieve, which are normally unachievable with- out an agreement among all the agents who are involved in the bargaining. Through an alternating-offers procedure, an agreement among bargaining agents may be reached by ab- ductive reasoning. We show that the procedure converges to a Nash equilibrium if each agent makes rational offers/counter- offers in each round. In addition, the sequential model also has a number of desirable properties, such as mutual commit- ments, individual rationality, satisfactoriness, and honesty.展开更多
Checking if a program has an answer set, and if so, compute its answer sets are just some of the important problems In answer set logic progremming. Solving these problems using Gelfond and Llfschltz's original defin...Checking if a program has an answer set, and if so, compute its answer sets are just some of the important problems In answer set logic progremming. Solving these problems using Gelfond and Llfschltz's original definition of answer sets Is not an easy task. Alternative charaoterlzatlons of answer sets for nested logic programs by Erdem and Llfschltz, Lee and Llfschltz, and You at el. are based on the completion semantics and various notions of tlghtnese. However, the notion of tightness Is a local notion In the sense that for different answer sets there are, In general, different level mappings capturing their tlghtnese. This makes It hard to be used In the deelgn of algorithms for computing answer sets. This paper proposes a charecterization of answer sets based on sets of generetlng rules. From this charaoterlzation new algorithms are derived for computing answer sets and for performing some other reasoning teaks. As an application of the charecterlzatlon a sufficient and necessary condition for the equivalence between answer set sementics and completion semantics has been proven, and a basic theorem Is shown on computing answer sets for nested logic programs baaed on an extended notion of loop formulas. These results on tlghtnese and loop formulas are more general than that in You and Lin'a work.展开更多
Based on the study of the current two methods—interpretation and compilation—for the integration of logic programming and relational database,a new precompilation-based interpretive approach is proposed.It inherits ...Based on the study of the current two methods—interpretation and compilation—for the integration of logic programming and relational database,a new precompilation-based interpretive approach is proposed.It inherits the advantages of both methods,but overcomes the drawbacks of theirs.A new integrated system based on this approach is presented,which has been implemented on Micro VAX Ⅱ and applied to practise as the kernel of the GKBMS knowledge base management system.Also discussed are the key implementation techniques,including the coupling of logic and relational database systems,the compound of logic and relational database languages,the partial evaluation and static optimization of user's programs,fact scheduling and version management in problem-solving.展开更多
Many reduction systems have been presented for implementing functional programming languages. We propose here an extension of a reduction architecture to realize a kind of logic programming——pure Horn clause logic p...Many reduction systems have been presented for implementing functional programming languages. We propose here an extension of a reduction architecture to realize a kind of logic programming——pure Horn clause logic programming.This is an attempt to approach amalgama- tion of the two important programming paradigms.展开更多
A homomorphism φ of logic programs from P to P' is a function mapping Atoms(P) to Atoms(P') and it preserves complements and program clauses. For each definite program clause a ← a1,...,an ∈ P it implies that...A homomorphism φ of logic programs from P to P' is a function mapping Atoms(P) to Atoms(P') and it preserves complements and program clauses. For each definite program clause a ← a1,...,an ∈ P it implies that φ(a) ←- φ(a1),...,φ(an) is a program clause of P'. A homomorphism φis an isomorphism if φ is a bijection. In this paper, the complexity of the decision problems on homomorphism and isomorphism for definite logic programs is studied. It is shown that the homomorphism problem (HOM-LP) for definite logic programs is NP-complete, and the isomorphism problem (ISO-LP) is equivalent to the graph isomorphism problem (GI).展开更多
This paper presents a framework called logical knowledge object (LKO),which is taken as a basis of the dependable development of knowledge based systems(KBSs). LKO combines logic programming and object-oriented progra...This paper presents a framework called logical knowledge object (LKO),which is taken as a basis of the dependable development of knowledge based systems(KBSs). LKO combines logic programming and object-oriented programming paradigms, where objects are viewed as abstractions with states,constraints, behaviors and inheritance. The operational semantics defined in the style of natural semantics is simple and clear. A hybrid knowledge represen-tation amalgamating rule, frame, semantic network and blackboard is available for both most structured and flat knowledge. The management of knowledge bases has been formally specified. Accordingly, LKO is well suited for the formal representation of knowledge and requirements of KBSs. Based on the framework, verification techniques are also explored to enhance the analysis of requirement specifications and the validation of KBSs. In addition, LKO pro-vides a methodology for the development of KBSs, applying the concepts of rapid prototyping and top-down design to deal with changing and incomplete requirements, and to provide multiple abstract models of the domain, where formal methods might be used at each abstract level.展开更多
文摘To overcome inefficiency in traditional logic programming, a declarative programming language COPS is designed based on the notion of concurrent constraint programming (CCP). The improvement is achieved by the adoption of constraint-based heuristic strategy and the introduction of deterministic components in the framework of CCP. Syntax specification and an operational semantic description are presented.
文摘LP (Logic Programming) has been successfully applied to knowledge discovery in many fields. The execution of the LP is based on the evaluation of the first order predicate. Usually the information involved in the predicates are local and homogenous, thus the evaluation process is relatively simple. However, the evaluation process become much more complicated when applied to KDD on the Internet where the information involved in the predicates maybe heterogeneous and distributed over many different sits. Therefor, we try to attack the problem in a multi agent system's framework so that the logic program can be written in a site independent style and deal easily with heterogeneous represented information.
基金This work was supported by National Key RD Program of China under Grant 2017YFB0802901.
文摘Code defects can lead to software vulnerability and even produce vulnerability risks.Existing research shows that the code detection technology with text analysis can judge whether object-oriented code files are defective to some extent.However,these detection techniques are mainly based on text features and have weak detection capabilities across programs.Compared with the uncertainty of the code and text caused by the developer’s personalization,the programming language has a stricter logical specification,which reflects the rules and requirements of the language itself and the developer’s potential way of thinking.This article replaces text analysis with programming logic modeling,breaks through the limitation of code text analysis solely relying on the probability of sentence/word occurrence in the code,and proposes an object-oriented language programming logic construction method based on method constraint relationships,selecting features through hypothesis testing ideas,and construct support vector machine classifier to detect class files with defects and reduce the impact of personalized programming on detection methods.In the experiment,some representative Android applications were selected to test and compare the proposed methods.In terms of the accuracy of code defect detection,through cross validation,the proposed method and the existing leading methods all reach an average of more than 90%.In the aspect of cross program detection,the method proposed in this paper is superior to the other two leading methods in accuracy,recall and F1 value.
基金This work was funded by the National Natural Science Foundation of China Nos.U22A2099,61966009,62006057the Graduate Innovation Program No.YCSW2022286.
文摘Humans are experiencing the inclusion of artificial agents in their lives,such as unmanned vehicles,service robots,voice assistants,and intelligent medical care.If the artificial agents cannot align with social values or make ethical decisions,they may not meet the expectations of humans.Traditionally,an ethical decision-making framework is constructed by rule-based or statistical approaches.In this paper,we propose an ethical decision-making framework based on incremental ILP(Inductive Logic Programming),which can overcome the brittleness of rule-based approaches and little interpretability of statistical approaches.As the current incremental ILP makes it difficult to solve conflicts,we propose a novel ethical decision-making framework considering conflicts in this paper,which adopts our proposed incremental ILP system.The framework consists of two processes:the learning process and the deduction process.The first process records bottom clauses with their score functions and learns rules guided by the entailment and the score function.The second process obtains an ethical decision based on the rules.In an ethical scenario about chatbots for teenagers’mental health,we verify that our framework can learn ethical rules and make ethical decisions.Besides,we extract incremental ILP from the framework and compare it with the state-of-the-art ILP systems based on ASP(Answer Set Programming)focusing on conflict resolution.The results of comparisons show that our proposed system can generate better-quality rules than most other systems.
文摘Due to the emergence of a large number of counterfeit notes and incomplete coins in the slot machine of self-service bus, to improve the automization of intelligent slot machine, based on multi-sensor testing technology, using programming log- ic controller (PLC) as the core of the whole system, the PLC hardware design and software design are accomplished for the first time to detect the counterfeit notes and coins. The system was tested by many groups of experiments. The results show that the system has reliable recognition rate, good flexibility and stability, reaching the accuracy of 97%.
基金Aeronautical Science Foundation !( 97D5 3 0 3 7)
文摘First, the concept of cooperative conflict is presented, and the characteristic of cooperative air combat is researched. Then, four methods of conflict resolution are designed by way of the first order predicate logic, i.e., link-up, coordination, accommodation and integration, and corresponding examples are given. A 2 vs 2 air combat simulation was carried out; after conflict resolution, the loss ratio is dropped to 0.54 from the original 1.32, so the enhancement of effectiveness is notable. The present research findings are that the wide conflicts discover the essence of multi-fighter cooperation, i.e., to as fully as possible enhance the effectiveness of each fighter to attain global optimization, and that the possibility of conflict resolution shows the application prospect. The proposed method in this paper is a helpful try to the application of the Fifth Generation Computer in the new generation of C3I system.
基金the National Natural Science Foundation of China (60573009,90718009)
文摘Based on logic programs, authorization conflicts and resolution strategies are analyzed through the explanation of some examples on the health care sector. A resolution scheme for handling conflicts in high level authorization specification by using logic program with ordered disjunction (LPOD) is proposed. The scheme is useful for solving conflicts resulted from combining positive and negative authorization, complexity of authorization management, and less clarity of the specification. It can well specify kinds of conflicts (such as exceptional conflicts, potential conflicts), and is based on literals and dependent contexts. Thus it is expressive and available. It is shown that authorizations based on rules LPOD is very important both in theory and practice.
基金Supported in part by the Ministry of EducationCulture+2 种基金SportsScience and TechnologyGrant-in-Aid for Scien-tific Research (B)
文摘We describe a system called CFLP which aims at the integration of the best features of functional logic programming (FLP), cooperative constraint solving (CCS), and distributed computing. FLP provides support for defining one's own abstractions over a constraint domain in an easy and comfortable way, whereas CCS is employed to solve systems of mixed constraints by iterating specialized constraint solving methods in accordance with a well defined strategy. The system is a distributed implementation of a cooperative constraint functional logic programming scheme that combines higher order lazy narrowing with cooperative constraint solving. The model takes advantage of the existence of several constraint solving resources located in a distributed environment (e.g., a network of computers), which communicate asynchronously via message passing. To increase the openness of the system, we are redesigning CFLP based on CORBA. We discuss some design and implementation issues of the system.
基金This work is supported by Ministry of Higher Education(MOHE)through Fundamental Research Grant Scheme(FRGS)(FRGS/1/2020/STG06/UTHM/03/7).
文摘Radial Basis Function Neural Network(RBFNN)ensembles have long suffered from non-efficient training,where incorrect parameter settings can be computationally disastrous.This paper examines different evolutionary algorithms for training the Symbolic Radial Basis Function Neural Network(SRBFNN)through the behavior’s integration of satisfiability programming.Inspired by evolutionary algorithms,which can iteratively find the nearoptimal solution,different Evolutionary Algorithms(EAs)were designed to optimize the producer output weight of the SRBFNN that corresponds to the embedded logic programming 2Satisfiability representation(SRBFNN-2SAT).The SRBFNN’s objective function that corresponds to Satisfiability logic programming can be minimized by different algorithms,including Genetic Algorithm(GA),Evolution Strategy Algorithm(ES),Differential Evolution Algorithm(DE),and Evolutionary Programming Algorithm(EP).Each of these methods is presented in the steps in the flowchart form which can be used for its straightforward implementation in any programming language.With the use of SRBFNN-2SAT,a training method based on these algorithms has been presented,then training has been compared among algorithms,which were applied in Microsoft Visual C++software using multiple metrics of performance,including Mean Absolute Relative Error(MARE),Root Mean Square Error(RMSE),Mean Absolute Percentage Error(MAPE),Mean Bias Error(MBE),Systematic Error(SD),Schwarz Bayesian Criterion(SBC),and Central Process Unit time(CPU time).Based on the results,the EP algorithm achieved a higher training rate and simple structure compared with the rest of the algorithms.It has been confirmed that the EP algorithm is quite effective in training and obtaining the best output weight,accompanied by the slightest iteration error,which minimizes the objective function of SRBFNN-2SAT.
文摘We discuss the projection temporal logic (PTL), based on a primitiveprojection operator, prj. A framing technique is also presented, using which a synchronizationoperator, await, is defined within the underlying logic. A framed temporal logic programminglanguage (FTLL) is presented. To illustrate how to use both the language and framing technique, someexamples are given.
基金This work is supported by the National Natural Science Foundation of China under Grand No. 60496322 and the Chinese Ministry of Education under Grand No. 05JZD720.4001.
文摘Currently, agent-based computing is an active research area, and great efforts have been made towards the agent-oriented programming both from a theoretical and practical view. However, most of them assume that there is no uncertainty in agents' mental state and their environment. In other words, under this assumption agent developers are just allowed to specify how his agent acts when the agent is 100% sure about what is true/false. In this paper, this unrealistic assumption is removed and a new agent-oriented probabilistic logic programming language is proposed, which can deal with uncertain information about the world. The programming language is based on a combination of features of probabilistic logic programming and imperative programming.
基金supported by the National Natural Science Foundation of China under Grant Nos.90718009,60703095
文摘This paper presents a logic-program-based mechanism of negotiation between two agents. In this mechanism an extended logic program (ELP) is regarded as an agent. The negotiation process between two agents is then modelled as multiple encounters between two ELPs, each of which selects an answer set as its initial demand. Both agents mutually revise the original sets of demands through accepting part of the opponent's demand and/or giving up part of its own demand. The overall dynamics can be regarded as mutual updates between two extended logic programs. A deal to achieve an appropriate negotiation solution is put forward. The conditions of existence and terminability of an appropriate negotiation are given. Properties of a negotiation solution are discussed, including its weak Pareto optimality.
基金This research was partially supported by the National Natural Science Foundation of China under Grant Nos.60573011,10410638an MOE Project of Key Institute at Universities under Grant No.05JJD72040122.
文摘In this paper, it is shown that stable model semantics, perfect model semantics, and partial stable model semantics of disjunctive logic programs have the same expressive power with respect to the polynomial-time model-equivalent reduction. That is, taking perfect model semantics and stable model semantic as an example, any logic program P can be transformed in polynomial time to another logic program P' such that perfect models (resp. stable models) of P i-i correspond to stable models (resp. perfect models) of P', and the correspondence can be computed also in polynomial time. However, the minimal model semantics has weaker expressiveness than other mentioned semantics, otherwise, the polynomial hierarchy would collapse to NP.
基金Acknowledgements We thank for anonymous referees for their suggestions and comments. This research was based on work supported by grants from Science Foundation of China Project (60833001, 61100063, 61073040 and 61103023), and by a Humboldt Fellowship (X.Y.) from Alexander von Humboldt Foundation.
文摘Atomic blocks, a high-level language construct that allows programmers to explicitly specify the atomicity of operations without worrying about the implementations, are a promising approach that simplifies concurrent programming. On the other hand, temporal logic is a successful model in logic programming and concurrency verification, but none of existing temporal programming models supports concurrent programming with atomic blocks yet. In this paper, we propose a temporal programming model (αPTL) which extends the projection temporal logic (PTL) to support concurrent programming with atomic blocks. The novel construct that formulates atomic execution of code blocks, which we call atomic interval formulas, is always interpreted over two consecutive states, with the internal states of the block being abstracted away. We show that the framing mechanism in projection temporal logic also works in the new model, which consequently supports our development of an executive language. The language supports concurrency by introducing a loose interleaving semantics which tracks only the mutual exclusion between atomic blocks. We demonstrate the usage of αPTL by modeling and verifying both the fine-grained and coarse-grained concurrency.
文摘This paper proposes a sequential model of bar- gaining specifying reasoning processes of an agent be- hind bargaining procedures. We encode agents' background knowledge, demands, and bargaining constraints in logic pro- grams and represent bargaining outcomes in answer sets. We assume that in each bargaining situation, each agent has a set of goals to achieve, which are normally unachievable with- out an agreement among all the agents who are involved in the bargaining. Through an alternating-offers procedure, an agreement among bargaining agents may be reached by ab- ductive reasoning. We show that the procedure converges to a Nash equilibrium if each agent makes rational offers/counter- offers in each round. In addition, the sequential model also has a number of desirable properties, such as mutual commit- ments, individual rationality, satisfactoriness, and honesty.
基金Supported partially by the National Natural Science Foundation of China (Grant No. 60573009)Stadholder Foundation of Guizhou Province (Grant No. 2005(212)
文摘Checking if a program has an answer set, and if so, compute its answer sets are just some of the important problems In answer set logic progremming. Solving these problems using Gelfond and Llfschltz's original definition of answer sets Is not an easy task. Alternative charaoterlzatlons of answer sets for nested logic programs by Erdem and Llfschltz, Lee and Llfschltz, and You at el. are based on the completion semantics and various notions of tlghtnese. However, the notion of tightness Is a local notion In the sense that for different answer sets there are, In general, different level mappings capturing their tlghtnese. This makes It hard to be used In the deelgn of algorithms for computing answer sets. This paper proposes a charecterization of answer sets based on sets of generetlng rules. From this charaoterlzation new algorithms are derived for computing answer sets and for performing some other reasoning teaks. As an application of the charecterlzatlon a sufficient and necessary condition for the equivalence between answer set sementics and completion semantics has been proven, and a basic theorem Is shown on computing answer sets for nested logic programs baaed on an extended notion of loop formulas. These results on tlghtnese and loop formulas are more general than that in You and Lin'a work.
文摘Based on the study of the current two methods—interpretation and compilation—for the integration of logic programming and relational database,a new precompilation-based interpretive approach is proposed.It inherits the advantages of both methods,but overcomes the drawbacks of theirs.A new integrated system based on this approach is presented,which has been implemented on Micro VAX Ⅱ and applied to practise as the kernel of the GKBMS knowledge base management system.Also discussed are the key implementation techniques,including the coupling of logic and relational database systems,the compound of logic and relational database languages,the partial evaluation and static optimization of user's programs,fact scheduling and version management in problem-solving.
基金This work was done by the author when he was a visiting researcher in the research group of Prof.Dr.Werner Kluge at Kiel University,supported by the grant of Federal M ster of Science and Technology of Germany.
文摘Many reduction systems have been presented for implementing functional programming languages. We propose here an extension of a reduction architecture to realize a kind of logic programming——pure Horn clause logic programming.This is an attempt to approach amalgama- tion of the two important programming paradigms.
基金国家自然科学基金,the Special Foundation for Improving Scientific Research Condition of Guizhou, and the Government Foundation of Guizhou Province,the Government Foundation of Guizhou Province
文摘A homomorphism φ of logic programs from P to P' is a function mapping Atoms(P) to Atoms(P') and it preserves complements and program clauses. For each definite program clause a ← a1,...,an ∈ P it implies that φ(a) ←- φ(a1),...,φ(an) is a program clause of P'. A homomorphism φis an isomorphism if φ is a bijection. In this paper, the complexity of the decision problems on homomorphism and isomorphism for definite logic programs is studied. It is shown that the homomorphism problem (HOM-LP) for definite logic programs is NP-complete, and the isomorphism problem (ISO-LP) is equivalent to the graph isomorphism problem (GI).
文摘This paper presents a framework called logical knowledge object (LKO),which is taken as a basis of the dependable development of knowledge based systems(KBSs). LKO combines logic programming and object-oriented programming paradigms, where objects are viewed as abstractions with states,constraints, behaviors and inheritance. The operational semantics defined in the style of natural semantics is simple and clear. A hybrid knowledge represen-tation amalgamating rule, frame, semantic network and blackboard is available for both most structured and flat knowledge. The management of knowledge bases has been formally specified. Accordingly, LKO is well suited for the formal representation of knowledge and requirements of KBSs. Based on the framework, verification techniques are also explored to enhance the analysis of requirement specifications and the validation of KBSs. In addition, LKO pro-vides a methodology for the development of KBSs, applying the concepts of rapid prototyping and top-down design to deal with changing and incomplete requirements, and to provide multiple abstract models of the domain, where formal methods might be used at each abstract level.