We describe the current capabilities of a system for rule-based programming which is being developed by us. The system is called /spl rho/Log and consists of a pattern matching system and a strategic programming syste...
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We describe the current capabilities of a system for rule-based programming which is being developed by us. The system is called /spl rho/Log and consists of a pattern matching system and a strategic programming system embedded into a powerful system for symbolic and numeric computation. Matching with context and sequence variables, possibly constrained by regular constraints, is an elegant mechanism for retrieving data from objects described by tree-like data structures of arbitrary depth and breadth. The data selected by matching can be processed by successive applications of labeled conditional rewrite rules described by strategies. By integrating these mechanisms, we enable a highly declarative programming style which is useful especially for prototype implementations of deductive systems, solvers for various equational theories, tools for querying and translating XML, various evaluation strategies, etc.
Even if Java is widely used for agent development, some agent platforms employ ad-hoc programming languages, so the question that arises is: is there a language that fits the model of an autonomous software agent bett...
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Even if Java is widely used for agent development, some agent platforms employ ad-hoc programming languages, so the question that arises is: is there a language that fits the model of an autonomous software agent better than Java? This paper deals with such an issue by deriving an abstract model for agents and proposing some parameters to evaluate programming languages for agent development. As a result, the paper introduces Erlang, a functional language that presents some interesting characteristics for the engineering of agent-based applications. An Erlang-based platform, called eXAT and developed by the authors, is then presented. Finally, a comparison with a Java-based approach explains why, in the authors' opinion, this language cannot be considered a good choice for the implementation of agent systems.
Modern digital circuits consist of logic gates implemented in the complementary metal oxide semiconductor (CMOS) technology. The time taken for a logic gate output to change after one or more inputs have changed is ca...
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Modern digital circuits consist of logic gates implemented in the complementary metal oxide semiconductor (CMOS) technology. The time taken for a logic gate output to change after one or more inputs have changed is called the delay of the gate. A conventional CMOS gate is designed to have the same input to output delay irrespective of which input caused the output to change. We propose a new gate design that has different delays along various inputs to output paths within the gate. This is accomplished by inserting selectively sized "permanently on" series transistors at the inputs of the logic gate. We demonstrate the use of the variable input delay CMOS gates for a totally glitch-free minimum dynamic power implementation of a digital circuit. Applying a previously described linear programming method to the c7552 benchmark circuit, we obtained a power saving of 58% over an un-optimized design. This power consumption was 18% lower than that for an alternative low power design using conventional CMOS gates. All circuits had the same overall delay. Since the overall delay was not allowed to increase, the glitch elimination with conventional gates required insertion of delay buffers on non-critical paths. The use of the variable input delay gates drastically reduced the required number of delay buffers.
It is not sufficient to merely check the syntax of new policies before they are deployed in a system; policies need to be analyzed for their interactions with each other and with their local environment. That is, poli...
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It is not sufficient to merely check the syntax of new policies before they are deployed in a system; policies need to be analyzed for their interactions with each other and with their local environment. That is, policies need to go through a ratification process. We believe policy ratification becomes an essential part of system management as the number of policies in the system increases and as the system administration becomes more decentralized. In this paper, we focus on the basic tasks involved in policy ratification. To a large degree, these basic tasks can be performed independent of policy model and language and require little domain-specific knowledge. We present algorithms from constraint, linear, and logic programming disciplines to help perform ratification tasks. We provide an algorithm to efficiently assign priorities to the policies based on relative policy preferences indicated by policy administrators. Finally, with an example, we show how these algorithms have been integrated with our policy system to provide feedback to a policy administrator regarding potential interactions of policies with each other and with their deployment environment.
In this paper we solve a scheduling problem of a bottle production industry. This problem refers to a unique production line, and can be classified as a batch sizing and job sequencing problem. Regarding, the flexibil...
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In this paper we solve a scheduling problem of a bottle production industry. This problem refers to a unique production line, and can be classified as a batch sizing and job sequencing problem. Regarding, the flexibility requirements of the generality of industry to solve real problems, we present a solving method based on constraint logic programming (CLP). In this context we introduce a constraint based model of the problem and the corresponding solving method. In order to overcome some efficiency problems of CLP, an alternative method is also represented that integrates some techniques from linear programming. The tests done with the presented methods have shown promising results
We propose a novel approach for solving the optimal feedback control problem. Following our previous research, we formulate the problem as a Hamiltonian system by using the necessary conditions for optimality, and tre...
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ISBN:
(纸本)0780395670
We propose a novel approach for solving the optimal feedback control problem. Following our previous research, we formulate the problem as a Hamiltonian system by using the necessary conditions for optimality, and treat the resultant phase flow as a canonical transformation. Then starting from the Hamilton-Jacobi equation for generating functions we derive a set of 1st order quasilinear partial differential equations with the appropriate initial or terminal conditions, which forms the well-known Cauchy problem. These equations can also be derived by applying the invariant imbedding technique to the two point boundary value problem. The solution to this Cauchy problem is utilized for solving the Hamiltonian two point boundary value problem as well as the optimal feedback control problem with hard and soft constraint boundary conditions. As suggested by the illustrative examples given, this method is promising for solving problems with control constraints, non-smooth control logic, and non-analytic cost function.
Formal logic has been considered as one of the advanced topics in computing that students do not grasp easily. But the inherent nature of formal logic makes itself a natural choice for forming an overbearing organizin...
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Formal logic has been considered as one of the advanced topics in computing that students do not grasp easily. But the inherent nature of formal logic makes itself a natural choice for forming an overbearing organizing structure, which can be utilized in providing scaffolding during instructional process. This paper discusses the role of formal logic in teaching information science and information systems. We claim that formal logic can be used to realize the modern instruction design principles by ensuring activation of relevant prior knowledge and experiences when learner moves from one topic to another. The paper also describes the successful implementation and evaluation of an on-line teaching tool utilizing predicate logic notation to assist learners in mastering a difficult to learn Unix/Linux system administration command.
Due to the increasing test data volume needed to test corebased System-on-Chip, several test scheduling techniques minimizing the test application time have been proposed. In contrast to approaches where a fixed test ...
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Due to the increasing test data volume needed to test corebased System-on-Chip, several test scheduling techniques minimizing the test application time have been proposed. In contrast to approaches where a fixed test set for each core is assumed, we explore the possibility to use overlapping test patterns from the tests in the system. The overlapping tests serves as alternatives to the original dedicated test for the cores and, if selected, they are transported to the cores in a broadcasted manner so that several cores are tested concurrently. We have made use of a Constraint logic programming technique to select suitable tests for each core in the system and schedule the selected tests such that the test application time is minimized while designer-specified hardware constraints are satisfied. The experimental results indicate that we can on average reduce the test application time with 23%.
We extended general-purpose RISC processor architecture and developed a new RISC core, Casablanca II, for supporting real-time processing in embedded systems. The processor core has multiple register-sets and achieves...
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We extended general-purpose RISC processor architecture and developed a new RISC core, Casablanca II, for supporting real-time processing in embedded systems. The processor core has multiple register-sets and achieves fast context-switching by automatically changing the active register-set and reducing overheads to save and restore the contents of the registers when exceptions or interruptions occur. In addition, the core has mechanisms for explicit data cache control, enabling data prefetching and fast DMA, which is invoked by executing extended instructions. In this paper, we describe the organization of Casablanca II developed by using an ASIC process and present preliminary evaluation of the processor.
In the context of network management, Chomicki, Lobo and Naqvi have defined the specification language Policy Description Language (PDL) and later extended it by introducing monitors: constraints on the actions that t...
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In the context of network management, Chomicki, Lobo and Naqvi have defined the specification language Policy Description Language (PDL) and later extended it by introducing monitors: constraints on the actions that the network manager can execute simultaneously. This article proposes PPDL, an extension of PDL with preferences that allows the specification of user-defined preferences on how to apply monitors. The new language adopts Brewka's approach to preferences introducing the "/spl times/" ordered disjunction connective. We illustrate the feature of PPDL in two interesting application examples: i) the specification of "separation of duties" constraints on user/role assignments in a workflow scenario and ii) an architecture for Web services selection. Since PPDL (as well as PDL) policy specifications can be computed by means of translation into answer set programs, we are able to provide an integrated framework based on answer set programming inferential engine.
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