Geospatial information changes continually, and geospatial datasets become outdated and unsuitabl... more Geospatial information changes continually, and geospatial datasets become outdated and unsuitable for decision support due to inadequate data quality. They are also costly to maintain. There is a growing demand for accurate and consistent geospatial information in critical sectors such as emergency response. Within the land fabric geospatial vector data context, the ownership of data is distributed vertically among many
Wavelet Analysis method is considered as one of the most efficient methods for detecting DDoS att... more Wavelet Analysis method is considered as one of the most efficient methods for detecting DDoS attacks. However, during the peak data communication hours with a large amount of data transactions, this method is required to collect too many samples that will greatly increase the computational complexity. Therefore, the real-time response time as well as the accuracy of attack detection becomes very low. To address the above problem, we propose a new DDoS detection method called Modified Wavelet Analysis method which is based on the existing Isomap algorithm and wavelet analysis. In the paper, we present our new model and algorithm for detecting DDoS attacks and demonstrate the reasons of why we enlarge the Hurst's value of the self-similarity in our new approach. Finally we present an experimental evaluation to demonstrate that the proposed method is more efficient than the other traditional methods based on wavelet analysis.
The multi-version approach is useful in both synchronous and asynchronous groupware systems. This... more The multi-version approach is useful in both synchronous and asynchronous groupware systems. This paper discusses the implementation of a real-time group editor that embodies our approaches and algorithms based on multi-versioning, which can preserve individual users' concurrent conflicting intentions in a consistent way. To highlight the distinct contributions of our work, we also present a detailed description of some novel features of the system
We propose a temporal extension of Datalog which can be used to model and query temporal database... more We propose a temporal extension of Datalog which can be used to model and query temporal databases with relations based on multiple clocks. The extension, called Clocked Temporal Datalog, is based on a clocked temporal logic in which each formula can be assigned a separate clock. A Clocked Temporal Datalog program consists of three parts: (1) a clock definition, (2) a clock assignment, and (3) a program body. The clock definition specifies all the available clocks. The clock assignment assigns to each predicate defined in the program body a clock from the clock definition. The meaning of the program body naturally depends on the provided clock definition and assignment. Therefore a Clocked Temporal Datalog program models intensionally a clocked (temporal) database in which each relation is defined over a clock.
The goal of clustering in data mining is to distinguish objects into partitions/clusters based on... more The goal of clustering in data mining is to distinguish objects into partitions/clusters based on given criteria. Visualization methods and techniques may provide users an intuitively appealing interpretation of cluster structures. Having good visually separated groups of the studied data is beneficial for detecting cluster information as well as refining the membership formation of clusters. In this paper, we propose a novel visual approach called M-mapping, based on the projection technique of HOV3 to achieve the separation of cluster structures. With M-mapping, users can explore visual cluster clues intuitively and validate clusters effectively by matching the geometrical distributions of clustered and non-clustered subsets produced in HOV3.
IEEE Transactions on Systems, Man, and Cybernetics, 2006
In this paper, we introduce a basic conceptual model of real-time collaborative editing systems w... more In this paper, we introduce a basic conceptual model of real-time collaborative editing systems which differentiates the coordination aspect of actions (which do not exist in single-user systems) from the application-dependent semantic aspect of actions (i.e., those actions that happen in single-user systems). Based on this model, a new taxonomy is provided to analyze the existing consistency-maintenance mechanisms and highlight potential new mechanisms. Furthermore, a new user-centered consistency model is proposed, which focuses on dynamic consistency that is negotiable among end users rather than static consistency that is automatically determined by the system. In the mean time, some challenging research issues in real-time collaborative editing systems are outlined
To develop theories to specify and reason about various aspects of multi-agent systems, many rese... more To develop theories to specify and reason about various aspects of multi-agent systems, many researchers have proposed the use of modal logics such as belief logics, logics of knowledge, and logics of norms. As multi-agent systems operate in dynamic environments, there is also a need to model the evolution of multi-agent systems through time. In order to introduce a temporal dimension to a belief logic, we combine it with a linear-time temporal logic using a powerful technique called fibring for combining logics. We describe a labelled modal tableaux system for a fibred belief logic (FL) which can be used to automatically verify correctness of inter-agent stream authentication protocols. With the resulting fibred belief logic and its associated modal tableaux, one is able to build theories of trust for the description of, and reasoning about, multi-agent systems operating in dynamic environments.
By this study, it is aimed to build a general agent framework to simulate human-like intelligence... more By this study, it is aimed to build a general agent framework to simulate human-like intelligence. For this purpose, theories of needs and intentional notion are combined together. To explain motives, Alderfer's needs theory which is based on the ideas of Maslow is adopted. In this manner, it is tried to define the needs of human-beings as the cause of emergence of intelligence. Intelligent entities are considered as entities driven by unsatisfied needs, to satisfy these motives they act intentionally. Based on these ideas, we present an architecture to mimic all aspects of human intelligence.
To develop believable agents, agents should be highly autonomous, situated, flexible, and emotion... more To develop believable agents, agents should be highly autonomous, situated, flexible, and emotional. By this study, our aim is to present an agent architecture called Reactive-Causal Architecture that supports development of believable agents.
Knowledge specification can be used as a basis for developing and maintaining simulation systems.... more Knowledge specification can be used as a basis for developing and maintaining simulation systems. This paper presents a knowledge specification methodology based on the temporal logic TLC for solving simulation problems. In this methodology, we build a specific constraint mechanism as a standard prototype for a class of simulation problems which may have some common properties. Such a standard prototype can be used to test and improve the knowledge specification of the target system of any problem belonging to this class. When we obtain a satisfactory knowledge specification, a simulation program in Chronolog(MC), a logic programming language based on TLC, can be produced.
Representation, reasoning about and integrating knowledge based on multiple time granularities in... more Representation, reasoning about and integrating knowledge based on multiple time granularities in knowledge-based systems is important, especially when talking about events that take place in the real world. Formal approaches based on temporal logics have been successfully applied in many application domains of knowledge-based systems where the evolution of a system and its environment through time is central. This paper presents a methodology based on temporal logic to deal with knowledge based on multiple time granularities in knowledge-based systems. The temporal logic we consider is especially suitable for modelling events with different rates and/or scales of progress. The methodology includes an approach to the representation of timing systems, a method used for representing facts and rules in a knowledge-based system that involve multiple time granularities using temporal logic, and several deductive reasoning techniques.
Skip to Main Content. IEEE.org | IEEE Xplore Digital Library | IEEE Standards Association | Spect... more Skip to Main Content. IEEE.org | IEEE Xplore Digital Library | IEEE Standards Association | Spectrum Online | More IEEE Sites. IEEE Xplore Digital Library. Search Term(s). Advanced Search | Preferences | Search Tips. ...
This paper presents a global layout approach used in a generalpurpose visual language generation ... more This paper presents a global layout approach used in a generalpurpose visual language generation system system. Our approach is grammarbased graph drawing, in which layout rules are embedded in the productions of reserved graph grammars. Thus, the grammar formalism serves both the visual language grammar and the layout grammar. An example visual language is demonstrated.
This paper introduces Chronolog(Z), a logic programming language based on a discrete linear-time ... more This paper introduces Chronolog(Z), a logic programming language based on a discrete linear-time temporal logic with unbounded past and future. Chronolog(Z) is suitable for applications involving the notion of dynamic change such as modeling nonterminating computations, the simulation of sequential circuits, and temporal databases. The execution of the programs of the language is based on a resolution-type proof procedure called TiSLD-resolution. A modular extension of Chronolog(Z) is proposed which can be used to model objects with internal memory.
The goal of an authentication system is to verify and authorise users, in order to protect restri... more The goal of an authentication system is to verify and authorise users, in order to protect restricted data and information. After authentication, two principals (people, computers, services) in a distributed system should be entitled to believe that they are communicating with each other and not with intruders. Therefore it is important to express such beliefs precisely and to capture the reasoning that leads to them. In this paper, we focus on analysis of agent beliefs in dynamic environments in a formal framework based on a combination of a belief logic with a temporal logic. Through a well-known protocol example, that is, Kerberos, we discuss how to express principal agent beliefs involved in authentication protocols and the evolution of these beliefs as a consequence of communication, since trust is based on a series of observations of agents. Our approach is general and could be used for designing, verifying and implementing authentication protocols
With the much increased capability of data collection and storage in the past decade, data miners... more With the much increased capability of data collection and storage in the past decade, data miners have to deal with much larger datasets in knowledge discovery tasks. Very large observations may cause traditional clustering methods to break down and not be able to cope with such large volumes of data. To enable data miners effectively detect the hierarchical cluster structure of a very large dataset, we introduce a visualization technique HOV3 to plot the dataset into clear and meaningful subsets by using its statistical summaries. Therefore, data miners can focus on investigating a relatively smaller-sized subset and its nested clusters. In such a way, data miners can explore clusters of any subset and its offspring subsets in a top-down fashion. As a consequence, HOV3 provides data miners an effective method on the exploration of clusters in a hierarchy by visualization.
We present a new model of knowledge, belief, desire and intention, called the interpreted KBDI-sy... more We present a new model of knowledge, belief, desire and intention, called the interpreted KBDI-system model (or KBDI-model for short). The key point of the interpreted KBDI-system model is that we express an agent’s knowledge, belief, desire and intention as a set of runs (computing paths), which is exactly a system in the interpreted system model, a well-known agent model due to Halpern and his colleagues. Our KBDI-model is computationally grounded in that we are able to associate a KBDI-model with a computer program, and formulas, involving agents’ knowledge, belief, desire (goal) and intention, can be understood as properties of program computations. With KBDI-model, we have two different semantics to interpret our logic of knowledge, belief, desire and intention. Moreover, with respect to each semantics, we present a sound and complete proof system.
Geospatial information changes continually, and geospatial datasets become outdated and unsuitabl... more Geospatial information changes continually, and geospatial datasets become outdated and unsuitable for decision support due to inadequate data quality. They are also costly to maintain. There is a growing demand for accurate and consistent geospatial information in critical sectors such as emergency response. Within the land fabric geospatial vector data context, the ownership of data is distributed vertically among many
Wavelet Analysis method is considered as one of the most efficient methods for detecting DDoS att... more Wavelet Analysis method is considered as one of the most efficient methods for detecting DDoS attacks. However, during the peak data communication hours with a large amount of data transactions, this method is required to collect too many samples that will greatly increase the computational complexity. Therefore, the real-time response time as well as the accuracy of attack detection becomes very low. To address the above problem, we propose a new DDoS detection method called Modified Wavelet Analysis method which is based on the existing Isomap algorithm and wavelet analysis. In the paper, we present our new model and algorithm for detecting DDoS attacks and demonstrate the reasons of why we enlarge the Hurst's value of the self-similarity in our new approach. Finally we present an experimental evaluation to demonstrate that the proposed method is more efficient than the other traditional methods based on wavelet analysis.
The multi-version approach is useful in both synchronous and asynchronous groupware systems. This... more The multi-version approach is useful in both synchronous and asynchronous groupware systems. This paper discusses the implementation of a real-time group editor that embodies our approaches and algorithms based on multi-versioning, which can preserve individual users' concurrent conflicting intentions in a consistent way. To highlight the distinct contributions of our work, we also present a detailed description of some novel features of the system
We propose a temporal extension of Datalog which can be used to model and query temporal database... more We propose a temporal extension of Datalog which can be used to model and query temporal databases with relations based on multiple clocks. The extension, called Clocked Temporal Datalog, is based on a clocked temporal logic in which each formula can be assigned a separate clock. A Clocked Temporal Datalog program consists of three parts: (1) a clock definition, (2) a clock assignment, and (3) a program body. The clock definition specifies all the available clocks. The clock assignment assigns to each predicate defined in the program body a clock from the clock definition. The meaning of the program body naturally depends on the provided clock definition and assignment. Therefore a Clocked Temporal Datalog program models intensionally a clocked (temporal) database in which each relation is defined over a clock.
The goal of clustering in data mining is to distinguish objects into partitions/clusters based on... more The goal of clustering in data mining is to distinguish objects into partitions/clusters based on given criteria. Visualization methods and techniques may provide users an intuitively appealing interpretation of cluster structures. Having good visually separated groups of the studied data is beneficial for detecting cluster information as well as refining the membership formation of clusters. In this paper, we propose a novel visual approach called M-mapping, based on the projection technique of HOV3 to achieve the separation of cluster structures. With M-mapping, users can explore visual cluster clues intuitively and validate clusters effectively by matching the geometrical distributions of clustered and non-clustered subsets produced in HOV3.
IEEE Transactions on Systems, Man, and Cybernetics, 2006
In this paper, we introduce a basic conceptual model of real-time collaborative editing systems w... more In this paper, we introduce a basic conceptual model of real-time collaborative editing systems which differentiates the coordination aspect of actions (which do not exist in single-user systems) from the application-dependent semantic aspect of actions (i.e., those actions that happen in single-user systems). Based on this model, a new taxonomy is provided to analyze the existing consistency-maintenance mechanisms and highlight potential new mechanisms. Furthermore, a new user-centered consistency model is proposed, which focuses on dynamic consistency that is negotiable among end users rather than static consistency that is automatically determined by the system. In the mean time, some challenging research issues in real-time collaborative editing systems are outlined
To develop theories to specify and reason about various aspects of multi-agent systems, many rese... more To develop theories to specify and reason about various aspects of multi-agent systems, many researchers have proposed the use of modal logics such as belief logics, logics of knowledge, and logics of norms. As multi-agent systems operate in dynamic environments, there is also a need to model the evolution of multi-agent systems through time. In order to introduce a temporal dimension to a belief logic, we combine it with a linear-time temporal logic using a powerful technique called fibring for combining logics. We describe a labelled modal tableaux system for a fibred belief logic (FL) which can be used to automatically verify correctness of inter-agent stream authentication protocols. With the resulting fibred belief logic and its associated modal tableaux, one is able to build theories of trust for the description of, and reasoning about, multi-agent systems operating in dynamic environments.
By this study, it is aimed to build a general agent framework to simulate human-like intelligence... more By this study, it is aimed to build a general agent framework to simulate human-like intelligence. For this purpose, theories of needs and intentional notion are combined together. To explain motives, Alderfer's needs theory which is based on the ideas of Maslow is adopted. In this manner, it is tried to define the needs of human-beings as the cause of emergence of intelligence. Intelligent entities are considered as entities driven by unsatisfied needs, to satisfy these motives they act intentionally. Based on these ideas, we present an architecture to mimic all aspects of human intelligence.
To develop believable agents, agents should be highly autonomous, situated, flexible, and emotion... more To develop believable agents, agents should be highly autonomous, situated, flexible, and emotional. By this study, our aim is to present an agent architecture called Reactive-Causal Architecture that supports development of believable agents.
Knowledge specification can be used as a basis for developing and maintaining simulation systems.... more Knowledge specification can be used as a basis for developing and maintaining simulation systems. This paper presents a knowledge specification methodology based on the temporal logic TLC for solving simulation problems. In this methodology, we build a specific constraint mechanism as a standard prototype for a class of simulation problems which may have some common properties. Such a standard prototype can be used to test and improve the knowledge specification of the target system of any problem belonging to this class. When we obtain a satisfactory knowledge specification, a simulation program in Chronolog(MC), a logic programming language based on TLC, can be produced.
Representation, reasoning about and integrating knowledge based on multiple time granularities in... more Representation, reasoning about and integrating knowledge based on multiple time granularities in knowledge-based systems is important, especially when talking about events that take place in the real world. Formal approaches based on temporal logics have been successfully applied in many application domains of knowledge-based systems where the evolution of a system and its environment through time is central. This paper presents a methodology based on temporal logic to deal with knowledge based on multiple time granularities in knowledge-based systems. The temporal logic we consider is especially suitable for modelling events with different rates and/or scales of progress. The methodology includes an approach to the representation of timing systems, a method used for representing facts and rules in a knowledge-based system that involve multiple time granularities using temporal logic, and several deductive reasoning techniques.
Skip to Main Content. IEEE.org | IEEE Xplore Digital Library | IEEE Standards Association | Spect... more Skip to Main Content. IEEE.org | IEEE Xplore Digital Library | IEEE Standards Association | Spectrum Online | More IEEE Sites. IEEE Xplore Digital Library. Search Term(s). Advanced Search | Preferences | Search Tips. ...
This paper presents a global layout approach used in a generalpurpose visual language generation ... more This paper presents a global layout approach used in a generalpurpose visual language generation system system. Our approach is grammarbased graph drawing, in which layout rules are embedded in the productions of reserved graph grammars. Thus, the grammar formalism serves both the visual language grammar and the layout grammar. An example visual language is demonstrated.
This paper introduces Chronolog(Z), a logic programming language based on a discrete linear-time ... more This paper introduces Chronolog(Z), a logic programming language based on a discrete linear-time temporal logic with unbounded past and future. Chronolog(Z) is suitable for applications involving the notion of dynamic change such as modeling nonterminating computations, the simulation of sequential circuits, and temporal databases. The execution of the programs of the language is based on a resolution-type proof procedure called TiSLD-resolution. A modular extension of Chronolog(Z) is proposed which can be used to model objects with internal memory.
The goal of an authentication system is to verify and authorise users, in order to protect restri... more The goal of an authentication system is to verify and authorise users, in order to protect restricted data and information. After authentication, two principals (people, computers, services) in a distributed system should be entitled to believe that they are communicating with each other and not with intruders. Therefore it is important to express such beliefs precisely and to capture the reasoning that leads to them. In this paper, we focus on analysis of agent beliefs in dynamic environments in a formal framework based on a combination of a belief logic with a temporal logic. Through a well-known protocol example, that is, Kerberos, we discuss how to express principal agent beliefs involved in authentication protocols and the evolution of these beliefs as a consequence of communication, since trust is based on a series of observations of agents. Our approach is general and could be used for designing, verifying and implementing authentication protocols
With the much increased capability of data collection and storage in the past decade, data miners... more With the much increased capability of data collection and storage in the past decade, data miners have to deal with much larger datasets in knowledge discovery tasks. Very large observations may cause traditional clustering methods to break down and not be able to cope with such large volumes of data. To enable data miners effectively detect the hierarchical cluster structure of a very large dataset, we introduce a visualization technique HOV3 to plot the dataset into clear and meaningful subsets by using its statistical summaries. Therefore, data miners can focus on investigating a relatively smaller-sized subset and its nested clusters. In such a way, data miners can explore clusters of any subset and its offspring subsets in a top-down fashion. As a consequence, HOV3 provides data miners an effective method on the exploration of clusters in a hierarchy by visualization.
We present a new model of knowledge, belief, desire and intention, called the interpreted KBDI-sy... more We present a new model of knowledge, belief, desire and intention, called the interpreted KBDI-system model (or KBDI-model for short). The key point of the interpreted KBDI-system model is that we express an agent’s knowledge, belief, desire and intention as a set of runs (computing paths), which is exactly a system in the interpreted system model, a well-known agent model due to Halpern and his colleagues. Our KBDI-model is computationally grounded in that we are able to associate a KBDI-model with a computer program, and formulas, involving agents’ knowledge, belief, desire (goal) and intention, can be understood as properties of program computations. With KBDI-model, we have two different semantics to interpret our logic of knowledge, belief, desire and intention. Moreover, with respect to each semantics, we present a sound and complete proof system.
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Papers by Mehmet Orgun