938 resultados para Concurrent programming
Resumo:
A programming style can be seen as a particular model of shaping thought or a special way of codifying language to solve a problem. An adaptive device is made up of an underlying formalism, for instance, an automaton, a grammar, a decision tree, etc., and an adaptive mechanism, responsible for providing features for self-modification. Adaptive languages are obtained by using some programming language as the device’s underlying formalism. The conception of such languages calls for a new programming style, since the application of adaptive technology in the field of programming languages suggests a new way of thinking. Adaptive languages have the basic feature of allowing the expression of programs which self-modifying through adaptive actions at runtime. With the adaptive style, programming language codes can be structured in such a way that the codified program therein modifies or adapts itself towards the needs of the problem. The adaptive programming style may be a feasible alternate way to obtain self-modifying consistent codes, which allow its use in modern applications for self-modifying code.
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An adaptive device is made up of an underlying mechanism, for instance, an automaton, a grammar, a decision tree, etc., to which is added an adaptive mechanism, responsible for allowing a dynamic modification in the structure of the underlying mechanism. This article aims to investigate if a programming language can be used as an underlying mechanism of an adaptive device, resulting in an adaptive language.
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Adaptive devices show the characteristic of dynamically change themselves in response to input stimuli with no interference of external agents. Occasional changes in behaviour are immediately detected by the devices, which right away react spontaneously to them. Chronologically such devices derived from researches in the field of formal languages and automata. However, formalism spurred applications in several other fields. Based on the operation of adaptive automata, the elementary ideas generanting programming adaptive languages are presented.
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A programming style can be seen as a particular model of shaping thought or a special way of codifying language to solve a problem. Adaptive languages have the basic feature of allowing the expression of programs which self-modifying through adaptive actions at runtime. The conception of such languages calls for a new programming style, since the application of adaptive technology in the field of programming languages suggests a new way of thinking. With the adaptive style, programming language codes can be structured in such a way that the codified program therein modifies or adapts itself towards the needs of the problem. The adaptive programming style may be a feasible alternate way to obtain self-modifying consistent codes, which allow its use in modern applications for self-modifying code.
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In this paper the architecture of an experimental multiparadigmatic programming environment is sketched, showing how its parts combine together with application modules in order to perform the integration of program modules written in different programming languages and paradigms. Adaptive automata are special self-modifying formal state machines used as a design and implementation tool in the representation of complex systems. Adaptive automata have been proven to have the same formal power as Turing Machines. Therefore, at least in theory, arbitrarily complex systems may be modeled with adaptive automata. The present work briefly introduces such formal tool and presents case studies showing how to use them in two very different situations: the first one, in the name management module of a multi-paradigmatic and multi-language programming environment, and the second one, in an application program implementing an adaptive automaton that accepts a context-sensitive language.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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This study investigated whether the opportunity to avoid or escape the open arms of an elevated plus-maze (EPM) affects the antinociceptive response observed when mice are subjected to open arm confinement. Furthermore, in order to better characterize the relationship between emotion and antinociception in the EPM, we examined the behavioral effects of midazolam injection into the midbrain periaqueductal gray matter (PAG). As our main aim was to evaluate the relevance of different levels of approach-avoid conflict (i.e. The presence of open and closed arms) to maze-induced antinociception, mice were exposed to one of three types of EPM-a standard EPM (sEPM), an open EPM (oEPM: four open arms) or, as a control condition, an enclosed EPM (eEPM: four enclosed arms). Nociception was assessed using the formalin test. Twenty minutes after formalin injection (50 mu l, 2.5% formalin) into the dorsal right hind paw, mice received an intra-PAG injection of saline or midazolam (10-20 nmol). Five minutes later, they were individually exposed to one of the mazes for 10 min (25-35 min after formalin injection). Videotapes of the test sessions were scored for a variety of behavioral measures including time spent licking the formalin-injected paw. To examine whether the effects of midazolam on anxiety-like behavior may have been influenced by concurrent nociceptive stimulation (i.e. formalin pretreatment), naive mice were submitted to a similar procedure to that described above for the sEPM test but without formalin pretreatment. Results showed that mice exposed to the oEPM spent significantly less time licking the injected paw compared to groups exposed to either the sEPM or eEPM. Although exposure to the sEPM induced anxiety-like behaviors (i.e. open arm avoidance), it did not result in antinociception. Intra-PAG infusions of midazolam failed to block oEPM-induced antinociception or to alter sEPM-induced anxiety in mice that had received formalin injection. However, under normal test conditions (i.e. in the absence of formalin-induced nociceptive stimulation), intra-PAG midazolam produced clear anti-anxiety effects in mice exposed to the sEPM. Findings are discussed in terms of different emotional states induced by the oEPM and sEPM and the influence of concurrent nociceptive stimulation on the anti-anxiety effect of intra-PAG midazolam. (c) 2005 Elsevier B.V. All rights reserved.
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This paper describes the development and solution of binary integer formulations for production scheduling problems in market-driven foundries. This industrial sector is comprised of small and mid-sized companies with little or no automation, working with diversified production, involving several different metal alloy specifications in small tailor-made product lots. The characteristics and constraints involved in a typical production environment at these industries challenge the formulation of mathematical programming models that can be computationally solved when considering real applications. However, despite the interest on the part of these industries in counting on effective methods for production scheduling, there are few studies available on the subject. The computational tests prove the robustness and feasibility of proposed models in situations analogous to those found in production scheduling at the analyzed industrial sector. (C) 2010 Elsevier Ltd. All rights reserved.
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The optimized allocation of protective devices in strategic points of the circuit improves the quality of the energy supply and the system reliability index. This paper presents a nonlinear integer programming (NLIP) model with binary variables, to deal with the problem of protective device allocation in the main feeder and all branches of an overhead distribution circuit, to improve the reliability index and to provide customers with service of high quality and reliability. The constraints considered in the problem take into account technical and economical limitations, such as coordination problems of serial protective devices, available equipment, the importance of the feeder and the circuit topology. The use of genetic algorithms (GAs) is proposed to solve this problem, using a binary representation that does (1) or does not (0) show allocation of protective devices (reclosers, sectionalizers and fuses) in predefined points of the circuit. Results are presented for a real circuit (134 busses), with the possibility of protective device allocation in 29 points. Also the ability of the algorithm in finding good solutions while improving significantly the indicators of reliability is shown. (C) 2003 Elsevier B.V. All rights reserved.
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This article presents a well-known interior point method (IPM) used to solve problems of linear programming that appear as sub-problems in the solution of the long-term transmission network expansion planning problem. The linear programming problem appears when the transportation model is used, and when there is the intention to solve the planning problem using a constructive heuristic algorithm (CHA), ora branch-and-bound algorithm. This paper shows the application of the IPM in a CHA. A good performance of the IPM was obtained, and then it can be used as tool inside algorithm, used to solve the planning problem. Illustrative tests are shown, using electrical systems known in the specialized literature. (C) 2005 Elsevier B.V. All rights reserved.
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Removing inconsistencies in a project is a less expensive activity when done in the early steps of design. The use of formal methods improves the understanding of systems. They have various techniques such as formal specification and verification to identify these problems in the initial stages of a project. However, the transformation from a formal specification into a programming language is a non-trivial task and error prone, specially when done manually. The aid of tools at this stage can bring great benefits to the final product to be developed. This paper proposes the extension of a tool whose focus is the automatic translation of specifications written in CSPM into Handel-C. CSP is a formal description language suitable for concurrent systems, and CSPM is the notation used in tools support. Handel-C is a programming language whose result can be compiled directly into FPGA s. Our extension increases the number of CSPM operators accepted by the tool, allowing the user to define local processes, to rename channels in a process and to use Boolean guards on external choices. In addition, we also propose the implementation of a communication protocol that eliminates some restrictions on parallel composition of processes in the translation into Handel-C, allowing communication in a same channel between multiple processes to be mapped in a consistent manner and that improper communication in a channel does not ocurr in the generated code, ie, communications that are not allowed in the system specification
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The aim of this work was to present organizational models for optimizing the reduction of crop residue generated by the sugarcane culture. The first model consisted of the selection of varieties of sugarcane to be planted meeting the mill requirements and, at the same time, to minimize the quantity of residue produced. The second model discussed the use of residue to produce energy. This is related to the selection of variety and quantity to be planted, in order to meet the requirements of the mill, to reduce the quantity of residue, and to maximize as much as possible the energy production. The use of linear programming was proposed. The two models presented similar results in this study, and both may be used to define the varieties and areas to be cultivated. (C) 2001 Published by Elsevier B.V. Ltd.