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Made available in DSpace on 2021-06-25T10:15:41Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-03-01 In this paper, a manufacturer of automotive springs is studied in order to reduce inventory costs and losses in the steel bar cutting process. For that, a mathematical model is proposed considering parallel machines and operational constraints, besides the demand, inventory costs and limits for items and final products. This one-dimensional integrated lot sizing and cutting stock problem is solved by a price-and-branch approach, using column generation and a method for obtaining integer solutions. Results using real data show that the proposed method achieved, in reasonable computational time, considerably better solutions than current practice at the company. Furthermore, focused on managerial insights, tests with random data were performed to analyze the influence that different parameters have in the solution, as well as the overall performance of the method. Paraná Federal University of Technology (UTFPR), Avenida dos Pioneiros, 3131, Jardim Morumbi, Londrina-PR São Paulo State University (UNESP) Avenida Eng. Luís Edmundo Carrijo Coube, 14-01, Vargem Limpa, Bauru-SP São Paulo State University (UNESP) Rua Cristóvão Colombo, 2265, Jardim Nazareth, São José do Rio Preto-SP São Paulo State University (UNESP) Avenida Eng. Luís Edmundo Carrijo Coube, 14-01, Vargem Limpa, Bauru-SP São Paulo State University (UNESP) Rua Cristóvão Colombo, 2265, Jardim Nazareth, São José do Rio Preto-SP

Made available in DSpace on 2020-12-12T01:14:53Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-01-01 This paper addresses the problem of multiple manufacturing modes integrated into the cutting stock problem, based on a real-life application of the concrete pole manufacturing. The main aim is to propose, formulate and test this integrated problem, which can be applied to the construction industry and other contexts of multiple manufacturing modes with cutting processes. The motivation for this proposal is the construction industry, in which reinforced concrete structures can be reinforced by various combinations of one-dimensional steel bars of varying thicknesses and lengths. An integer programming mathematical formulation is proposed aiming to minimise the total cost and to meet a demand of final products with different possible configurations. A column generation procedure is used as the solution method together with a heuristic procedure to find an integer solution. Computational results were performed with practical instances in order to assess the value of the approach and with a set of random generated instances in order to explore the influence of parameters on the results. Some managerial insights are presented. Faculdade de Engenharia de Bauru UNESP–São Paulo State University Faculdade de Ciências UNESP–São Paulo State University Instituto de Biociências Letras e Ciências Exatas UNESP–São Paulo State University Faculdade de Engenharia de Bauru UNESP–São Paulo State University Faculdade de Ciências UNESP–São Paulo State University Instituto de Biociências Letras e Ciências Exatas UNESP–São Paulo State University

The Portable Automated Rapid Test (PART) platform consists of a consumer electronics tablet and head-phones with software for assessing auditory perception. One goal of PART is to expand our knowledge of the hearing profile of individuals. The standard PART battery includes psychophysical measures that span multiple auditory perceptual domains. To date, most of the psychophysical measures in PART have been validated in quiet laboratory settings. It is unknown whether or how ambient or external noise will impact threshold measures. Subjects completed the PART battery in quiet over headphones (65 dB SPL) and in the presence of external cafeteria noise through loudspeakers (59 dB SPL; consistent with literature on waiting area noise). In separate conditions, we mixed pink noise through the headphones as a means to potentially mitigate the impacts of external noise (50 dB SPL; maximum level that did not impact thresholds). Thresh-old measures were collected from 10 young listeners with normal hearing. Results indicate that neither the pink noise nor the cafeteria noise affected average thresholds on any of the tasks relative to the quiet condition. These data support the use of PART in relatively uncontrolled listening environments like clinic waiting rooms or at home.

Made available in DSpace on 2020-12-12T01:14:12Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-01-01 In many productive processes, two important problems arise in the production planning: the lot-sizing problem and the cutting stock problem. Generally, companies deal with these problems separately but, by considering them in an integrated way, better results can be obtained. In this paper, the integrated lot-sizing and three-dimensional cutting stock problem applied to the mattress industry is investigated, aiming at reducing costs and waste. A mathematical model of mixed integer programming was proposed and solved with an optimisation package. Computational tests based on data collected at a mattress factory were carried out, allowing the comparison of the solutions proposed by the model and the solutions adopted by the factory. Additional tests were performed with random data in order to evaluate the behaviour of the model for different cases. The results indicate that the model performs well, reducing the objective function costs for different data sets. Based on the results, some interesting options can be explored by the industry; for example, by increasing the number of cutting patterns up to a certain level, the number of possible combinations for cutting is increased, resulting in better use of the material and a consequent reduction in costs. Universidade Estadual Paulista Júlio de Mesquita Filho (UNESP) - Campus de Bauru Universidade Estadual Paulista Júlio de Mesquita Filho - Campus de São José do Rio Preto Universidade Estadual Paulista Júlio de Mesquita Filho (UNESP) - Campus de Bauru Universidade Estadual Paulista Júlio de Mesquita Filho - Campus de São José do Rio Preto

Made available in DSpace on 2020-12-12T02:20:20Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-01-01 This paper addresses the integration of the lot-sizing problem and the one-dimensional cutting stock problem with usable leftovers (LSP-CSPUL). This integration aims to minimize the cost of cutting items from objects available in stock, allowing the bringing forward production of items that have known demands in a future planning horizon. The generation of leftovers, that will be used to cut future items, is also allowed and these leftovers are not considered waste in the current period. Inventory costs for items and leftovers are also considered. A mathematical model for the LSP-CSPUL is proposed to represent this problem and an approach, using the simplex method with column generation, is proposed to solve the linear relaxation of this model. A heuristic procedure, based on a relax-and-fix strategy, was also proposed to find integer solutions. Computational tests were performed and the results show the contributions of the proposed mathematical model, as well as, the quality of the solutions obtained using the proposed method. Departamento de Engenharia de Produção FEB UNESP Departamento de Matemática IBILCE UNESP Departamento de Matemática FC UNESP Departamento de Engenharia de Produção FEB UNESP Departamento de Matemática IBILCE UNESP Departamento de Matemática FC UNESP

An extended version of the flexible job shop problem is tackled in this work. The investigated extension of the classical flexible job shop problem allows the precedences between the operations to be given by an arbitrary directed acyclic graph instead of a linear order. The problem consists of designating the operations to the machines and sequencing them in compliance with the supplied precedences. The goal in the present work is the minimization of the makespan. In order to produce reasonable outcomes in acceptable time, a hybrid imperialist competitive algorithm and tabu search is proposed to solve the problem. Numerical experiments assess the efficiency of the proposed method and compare it with well-known scheduling algorithms.

Made available in DSpace on 2018-12-11T16:50:59Z (GMT). No. of bitstreams: 0 Previous issue date: 2017-12-17 As in many other combinatorial optimisation problems, research on nesting problems (aka irregular packing problems) has evolved around the dichotomy between continuous (time consuming) and discrete (memory consuming) representations of the solution space. Recent research has been devoting increasing attention to discrete representations for the geometric layer of nesting problems, namely in mathematical programming-based approaches. These approaches employ conventional regular meshes, and an increase in their precision has a high computational cost. In this paper, we propose a data structure to represent non-regular meshes, based on the geometry of each piece. It supports non-regular discrete geometric representations of the shapes, and by means of the proposed data structure, the discretisation can be easily adapted to the instances, thus overcoming the precision loss associated with discrete representations and consequently allowing for a more efficient implementation of search methods for the nesting problem. Experiments are conducted with the dotted-board model – a recently published mesh-based binary programming model for nesting problems. In the light of both the scale of the instances, which are now solvable, and the quality of the solutions obtained, the results are very promising. Instituto de Ciências Matemáticas e de Computação, Universidade de São Paulo, USP, São Carlos, Brasil Faculdade de Ciências, Universidade Estadual Paulista, UNESP, Bauru, Brasil Faculdade de Engenharia, INESC TEC, Universidade do Porto, Porto, Portugal

Traditional planning and scheduling techniques still hold important roles in modern smart scheduling systems. Realistic features present in modern manufacturing systems need to be incorporated into these techniques. The real-world problem addressed here is an extension of flexible job shop scheduling problem and is issued from the modern printing and boarding industry. The precedence between operations of each job is given by an arbitrary directed acyclic graph rather than a linear order. In this paper, we extend the traditional FJSP solutions representation to address the parallel operations. We propose an imperialist competitive algorithm for the problem. Several instances are used for the experiments and the results show that, for the considered instances, the proposed algorithm is faster and found better or equal solutions compared to the state-of-the-art algorithms.

Manufacturing scheduling strategies have historically ignored the availability of the machines. The more realistic the schedule, more accurate the calculations and predictions. Availability of machines will play a crucial role in the Industry 4.0 smart factories. In this paper, a mixed integer linear programming model (MILP) and a discrete firefly algorithm (DFA) are proposed for an extended multi-objective FJSP with availability constraints (FJSP-FCR). Several standard instances of FJSP have been used to evaluate the performance of the model and the algorithm. New FJSP-FCR instances are provided. Comparisons among the proposed methods and other state-of-the-art reported algorithms are also presented. Alongside the proposed MILP model, a Genetic Algorithm is implemented for the experiments with the DFA. Extensive investigations are conducted to test the performance of the proposed model and the DFA. The comparisons between DFA and other recently published algorithms shows that it is a feasible approach for the stated problem.

Predicting the complex behavior and aftermath of coastal tsunamis and storm surges is inherently difficult. Real-time disaster warning requires rapid computation with reliable accuracy and effective output presentation. The authors present two ways to leverage high-performance computing resources to address these challenges.

Various proposed optical computing devices involve nonlinear optical operation and use semiconductor optical amplifier (SOA)-based switches as fundamental elements for logic operations. Due to the nonlinear operation, these devices suffer from high power that causes problems in very large-scale optical integration. In this paper, a method is proposed to implement arithmetic operations using a photonic crystal (PhC) cell and eliminate the SOA-based switches altogether. The proposed method is employed on designing an all-optical full adder/subtractor circuit that requires only beam combiners and photonic crystal NOT gates.

In this article, we review published studies that consider the solution of the one-dimensional cutting stock problem (1DCSP) with the possibility of using leftovers to meet future demands, if long enough. The one-dimensional cutting stock problem with usable leftovers (1DCSPUL) is a problem frequently encountered in practical settings but often, it is not dealt with in an explicit manner. For each work reviewed, we present the application, the mathematical model if one is proposed and comments on the computational results obtained. The approaches are organized into three classes: heuristics, item-oriented, or cutting pattern-oriented.

Various designed circuits for multiple-valued all-optical arithmetic are demonstrated. The ter- ahertz-optical-asymmetric-demultiplexer (TOAD) switch is used as the basic structure unit in the proposed circuits due to its compact size, thermal stability, and low power operation. The designs of trinary and quaternary signed-digit numbers based adders are presented using different polar- ized states of light. These proposed polarization-encoded based adders use much less switches and their speeds are higher than the intensity-encoded counterparts. Further, it will be shown that one of the proposed trinary signed-digit adders is twice as fast as a recently reported modified signed-digit adder.

To examine the effects of different torsional flexibilities of shoes on gait and stability in children who are newly walking.Twenty-five children walking 5 months or less were evaluated barefoot and in 4 shoes with different torsional flexibilities (UltraFlex, MidFlex, LowFlex, and Stiff). Gait pattern was assessed using GaitMatII. Stability was determined by the number of stumbles/falls during functional tasks.Stance time was shorter barefoot compared with all shoe conditions (P = .000). Stance time was shorter in UltraFlex than in LowFlex (P = .000). Step width was wider in UltraFlex than in MidFlex and LowFlex (P = .028). Velocity, step length, and the number of stumbles/falls did not differ significantly across shoe conditions. Children walking for 2 months or less had significantly more stumbles and falls than children walking more than 2 months (P = .003).Stance time and step width differ across shoe conditions. Stability does not differ across shoe conditions.

We summarize the motivation and aims for this workshop on usability research challenges for cyberinfrastructure and tools, and outline workshop preparations and program.

Submitted by Guilherme Lemeszenski (guilherme@nead.unesp.br) on 2013-08-22T18:54:15Z No. of bitstreams: 1 S0101-74382011000100011.pdf: 2502203 bytes, checksum: c926f6400cd69e3085db9305b104cec9 (MD5) Made available in DSpace on 2013-08-22T18:54:15Z (GMT). No. of bitstreams: 1 S0101-74382011000100011.pdf: 2502203 bytes, checksum: c926f6400cd69e3085db9305b104cec9 (MD5) Previous issue date: 2011-04-01 Made available in DSpace on 2013-09-30T19:46:10Z (GMT). No. of bitstreams: 2 S0101-74382011000100011.pdf: 2502203 bytes, checksum: c926f6400cd69e3085db9305b104cec9 (MD5) S0101-74382011000100011.pdf.txt: 56136 bytes, checksum: ca053569277a4bda643c3cb17cad9d57 (MD5) Previous issue date: 2011-04-01 Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-20T15:12:10Z No. of bitstreams: 2 S0101-74382011000100011.pdf: 2502203 bytes, checksum: c926f6400cd69e3085db9305b104cec9 (MD5) S0101-74382011000100011.pdf.txt: 56136 bytes, checksum: ca053569277a4bda643c3cb17cad9d57 (MD5) Made available in DSpace on 2014-05-20T15:12:10Z (GMT). No. of bitstreams: 2 S0101-74382011000100011.pdf: 2502203 bytes, checksum: c926f6400cd69e3085db9305b104cec9 (MD5) S0101-74382011000100011.pdf.txt: 56136 bytes, checksum: ca053569277a4bda643c3cb17cad9d57 (MD5) Previous issue date: 2011-04-01 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Nesse trabalho, e estudado o problema de corte de estoque com sobras aproveitaveis (PCESA), que consiste em determinar uma política de aproveitamento das sobras de objetos cortados. Estas sobras, desde que não sejam demasiadamente pequenas, podem retornar ao estoque como retalhos para atender demandas futuras, não sendo, portanto, consideradas perdas. Para resolver o PCESA, podem ser utilizados varios procedimentos heurísticos propostos na literatura. Entretanto, e difícil identificar o melhor método de solução, pois cada um deles apresenta uma solução diferente em relação as características de interesse do problema, como quantidade de retalhos produzidos, perdas e distribuição de perdas e retalhos nos objetos. Para superar essa dificuldade, propoe-se utilizar técnicas da lógica fuzzy para considerar a contributo de cada característica de interesse na solução, classifica-la de acordo com critérios pré-estabelecidos e, finalmente, identificar o melhor método com base na respectiva solução. Com a metodologia fuzzy desenvolvida, facilitou-se a análise dos métodos de solução In this paper, we study the cutting stock problem with usable leftovers (CSPUL), that consists in determining a policy of usable leftovers from cut objects. These leftovers, if large enough, can returned to the stock as retails in order to fulfill future demands and, therefore, they are not computed as waste. In order to solve the CSPUL, several heuristic procedures from the literature can be used. However, it is hard to point out which solution method performs better, since each one presents different solutions regarding some conflicting characteristics, such as quantity of new retails generated, wastes, and distribution of the wastes and retails in the cut objects. To overcome this difficulty, we propose some fuzzy techniques to consider the contribution of each characteristic in the solution, classify it according some criteria beforehand considered and, finally, identify the best solution method based on the respective solution. With the proposed fuzzy methodology, the solution methods analysis was simplified Universidade Estadual Paulista Júlio de Mesquita Filho Departamento de Matemática Universidade Federal de São Carlos (UFSCar) Universidade de São Paulo EESC Departamento de Engenharia Elétrica Universidade Estadual Paulista Júlio de Mesquita Filho Departamento de Matemática

In contrast to optoelectronics, all-optical adders are proposed where all-optical signals are used to represent the input numbers and the control signals. In addition, the all-optical adders use the negabinary modified signed-digit number representation (an extension of the negabinary number system) to represent the input digits. Further, the ultra-speed of the designed circuits is achieved due to the use of ultra-fast all-optical switching property of the semiconductor optical amplifier and Mach–Zehnder interferometer (SOA–MZI). Furthermore, two-bit per digit binary encoding scheme is employed to represent the trinary values of the negabinary modified signed-digits.

In this work we consider a one-dimensional cutting stock problem in which the non-used material in the cutting patterns may be used in the future, if large enough. This feature introduces difficulties in comparing solutions of the cutting problem, for example, up to what extent a minimum leftover solution is the most interesting one when the leftover may be used. Some desirable characteristics of good solutions are defined and classical heuristic methods are modified, so that cutting patterns with undesirable leftover (not large enough to be used, nor too small to be acceptable waste) are redesigned. The performance of the modified heuristics is observed by solving instances from the literature, practical instances and randomly generated instances.

In this paper, a new configuration for the input joint images in the joint transform correlator is proposed for fast real-time binary characters and fingerprints verification. In the proposed scheme, the input joint image has a complementary-reference image and a complementary target image in addition to the reference and the target images. We use the cross-correlation peak value between the reference and the complementary target image and the cross-correlation peak value between the complementary reference and the target images as the criteria to perform the recognition of the target in the input scene. It is shown that these two cross-correlation peak values will be zero if and only if the input target matches the reference image. One advantage of using the proposed scheme is the elimination of the usual and necessary time-consuming normalization of the input images in the general correlation-based matching processes. Another advantage of the proposed scheme is the insensitive to light-sources intensity fluctuations that usually limits the matched-based recognition approaches. The scheme is employed to verify binary characters and fingerprints images; further, it is employed to verify occluded fingerprints target images on one hand, and to determine if a specific part or pattern exists in the target fingerprint image on the other hand.

Most of the algorithms proposed for face recognition involve considerable amount of computations and hence they cannot be used on devices constrained with limited memory. In this paper, we propose a novel solution for efficient face recognition problem for the systems that utilize low memory devices. The new technique applies the principal component analysis to the binarized phase spectrum of the Fourier transform of the covariance matrix constructed from the MPEG-7 Fourier Feature Descriptor vectors of the images. The binarization step that is applied to the phases adds many interesting advantages to the system. It will be shown that the proposed technique increases the face recognition rate and at the same time achieves substantial savings in the computational time, when compared to other known systems. Experiments on two independent databases of face images are reported to demonstrate the effectiveness of the proposed technique.

The spatial light modulators (SLMs) at the Fourier planes of a conventional joint-transform correlation (JTC) are eliminated using simple grating filters such as rectangular and triangular ones. To achieve this goal, two non-conventional real-time JTC architectures are proposed: (a) the grating filter is used along with a heterodyning and one-dimensional optical scanning technique to capture the cross-correlation functions of the input images without major processing and (b) the one-dimensional optical scanning is eliminated to achieve a faster (but a little bit more complicated) processing. The proposed techniques significantly reduce the time processing needed for real-time applications by eliminating the drawbacks of the non-ideal characteristics of the SLMs.

Made available in DSpace on 2018-11-12T17:26:00Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-12-01. Added 1 bitstream(s) on 2018-11-12T17:34:09Z : No. of bitstreams: 1 S0101-74382015000300509.pdf: 312249 bytes, checksum: 4bc12298f9546626b92ba1ef32e4355d (MD5) Made available in DSpace on 2018-11-12T17:26:00Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-12-01. Added 1 bitstream(s) on 2018-11-12T17:34:09Z : No. of bitstreams: 1 S0101-74382015000300509.pdf: 312249 bytes, checksum: 4bc12298f9546626b92ba1ef32e4355d (MD5) Made available in DSpace on 2018-11-12T17:26:00Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-12-01. Added 1 bitstream(s) on 2018-11-12T17:34:09Z : No. of bitstreams: 1 S0101-74382015000300509.pdf: 312249 bytes, checksum: 4bc12298f9546626b92ba1ef32e4355d (MD5) Made available in DSpace on 2018-11-12T17:26:00Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-12-01. Added 1 bitstream(s) on 2018-11-12T17:34:09Z : No. of bitstreams: 1 S0101-74382015000300509.pdf: 312249 bytes, checksum: 4bc12298f9546626b92ba1ef32e4355d (MD5) ABSTRACT This paper addresses the cutting stock/leftover problem (CSLP), which differs from the ordinary cutting stock problem (CSP) by retaining stock leftovers that can be cut in the future to meet new demands. Therefore, leftovers are not considered waste in the current period. A new mathematical model for the CSLP is presented to capture a well-used strategy in the practice of cutting, which consists of partially cutting the objects in stock, and keeping the leftovers to be cut in the next periods. Computational experiments were made for the one-dimensional case, although other dimensions can be considered straightforward. Universidade de São Paulo Instituto de Ciências Matemáticas e Computação Universidade Estadual Paulista Júlio de Mesquita Filho Departamento de Matemática Universidade Estadual Paulista Júlio de Mesquita Filho Departamento de Computação Universidade Estadual Paulista Júlio de Mesquita Filho Departamento de Matemática Universidade Estadual Paulista Júlio de Mesquita Filho Departamento de Computação

Neste trabalho, abordamos métodos de resolução para o problema de dimensionamento de lotes que contempla o planejamento da produção de vários produtos em múltiplas máquinas. A fabricação dos produtos consome tempo de produção e preparação de uma capacidade de produção limitada. A demanda pelos produtos é conhecida e pode ser atendida com atraso durante um horizonte de planejamento finito. O objetivo é minimizar a soma dos custos de produção, preparação para a produção, estoque dos produtos e atraso na entrega destes. Em uma primeira etapa, desenvolvemos uma busca tabu determinística baseada em outra, aleatória, que foi apresentada na literatura. Com isso, realizamos uma análise sobre a influência de fatores aleatórios sobre heurísticas do tipo busca tabu quando aplicadas ao problema estudado. Posteriormente, desenvolvemos um método híbrido baseado em busca tabu, branch-and-cut e programação linear para a resolução do problema. Nos testes computacionais realizados, o método proposto mostrou-se competitivo quando comparado a outras heurísticas apresentadas na literatura This paper proposes two methods to solve the capacitated lot-sizing problem with multiple products and parallel machines. The manufacturing of products consumes machines capacity (production time and setup time), which is scarce. The demand for the products is known and can be met with backlogging. The objective is to minimize the sum of production, setup, holding and backlog costs. In a first step, we developed a deterministic tabu search heuristic based on a random version from the literature and then conducted an analysis of the influence of random factors on tabu search heuristics when applied to solve the studied problem. Subsequently, we designed a hybrid method based on tabu search, branch-andcut and linear programming. Computational experiments show that this hybrid method is competitive with other heuristics presented in the literature

We consider the subtractive model repair problem: given a finite Kripke structure M and a CTL formula η, determine if M contains a substructure M' that satisfies η. Thus, M can be repaired to satisfy η by deleting states and/or transitions. We give a reduction to boolean satisfiability, and implement the repair method using this reduction. We also extend the basic repair method in three directions: (1) the use of abstraction, and (2) the repair of concurrent Kripke structures and concurrent programs, and (3) the repair of hierarchical Kripke structures. These last two extensions both avoid state-explosion.

Initial tools developed for grid administrators and users have built on the technology and representational techniques of large parallel systems. Like their predecessors, grid tools must cope with extreme variations in scale, rapidly evolving hardware and software environments, and the competing demands of operating systems and middleware. Computational grids present several unique challenges, however, that go well beyond the lessons we have learned from parallel and distributed tools: the volatile nature of grid resources, their extreme heterogeneity, and the lack of coordinated management. Because they define a new and unfamiliar computing environment, there is a significant human challenge as well. Grid users will be extremely diverse, including resource providers, resource managers, users of data and derived data products, etc., as well as application developers. The future usability of the grid will depend on how well grid tools can capture information on grid resources and synthesize a higher-level perspective that helps users make sense of this complex new environment. This article identifies the tool requirements that will have most impact on the usability. It then explores recent advances in information visualization, demonstrating that many of the techniques grid tools will need already exist in preliminary form. A series of examples illustrates how those techniques can be applied to portray grid landscapes (graphical representations of grid resources, activities, behavior, costs, etc.) in useful and meaningful ways.

The availability of massive amounts of high-quality data as well as advances in computing and communications suggest the possibility of powerful new applications in science, commerce, environment, and government-but many research challenges remain. Research in geospatial information systems is inherently multidisciplinary, and research efforts are likely to be most successful if conducted by teams that combine expertise in applications as well as information technology. Advances in location-aware computing, in particular, could have important implications not just for how geospatial data are acquired but also for how and with what quality they can be delivered and how mobile and geographically distributed systems are designed.

High-performance computing (HPC) application developers can no longer afford the luxury of programming to just one platform. The usefulness and longevity of software now depend on portability as well as performance. This paper examines the appropriateness of existing tools in developing and tuning applications that must be both efficient and portable. A series of design tradeoffs have been made, with the result that today's tools are slanted toward one goal or the other but do not respond adequately to both. These tradeoffs are explored through a series of examples drawn from current tools. Suggestions are presented for how tools might better support the evolving needs of HPC programmers.

A variety of algorithms for computing complex elementary functions based on the quaternary signed-digit (QSD) number system are proposed. An arithmetic unit that performs parallel one-step addition (subtraction), multiplication, and division is proposed to perform the computations of elementary functions such as square root, logarithmic, exponential, and other related functions. An optoelectronic-correlator-based architecture is suggested for implementing the proposed QSD elementary function algorithms. We used the symbolic substitution technique to reduce the number of the computation rules involved.

Scientific researchers are anxious to discover new insights into the relationships and interactions among the exceedingly diverse components of our physical, biological and ecological environment. To do this, individual scientists must be able to synthesize conclusions from data drawn from disciplines outside their domains of expertise. While key datasets have already been brought online, they are housed in diverse agencies, using different database software on a variety of platforms. This paper explores the problems in providing middleware and interface support for these autonomous research databases (ARD''s). The development of interfaces to ARD''s is complicated by the fact that potential end-users range from highly specialized research scientists to the general public. To adequately support such diverse users, the interface must assume different "personalities." We describe how interfaces can be targeted to three categories of end-users: domain specialists, non-domain specialists, and students. By automating the activities that are most frustrating, time-consuming, or error-prone, target-specific interfaces can significantly improve database usability. There is also heterogeneity among the people who must develop ARD interfaces. We target three different classes of implementers - database-technology familiar, database-content familiar, and database unfamiliar. By developing different middleware personalities that respond to the specific skills and interests of the audience, we have been able to keep our software simple and usable without sacrificing flexibility.

A quaternary signed-digit number representations-based arithmetic unit is proposed. The arithmetic unit performs parallel one-step addition (subtraction), multiplication and division. We use the symbolic substitution technique to reduce the number of the computation rules involved in the computation rules. Fast parallel nonrecoded quaternary signed-digit multiplication is proposed using our proposed one-step quaternary signed-digit adder. Also, parallel quaternary signed-digit division is performed in constant time by exploiting an iterative conversion algorithm where in every iterative step a negation operation, an addition operation and two multiplication operations are performed. The execution times of the proposed QSD operations are proportional to log2 n, where n are the length of operands.

A symbolic substitution (SS) based optical numeric processor using quaternary signed-digit (QSD) number representations is proposed. Also, we propose new joint spatial encodings for the QSD numbers that reduce the SS computation rules involved in the processor. Optoelectronic implementation of the proposed QSD adder is feasible. The proposed adder is more compact than recently reported QSD counterparts.

The modified signed-digit number representation is a redundant number system with radix=2. This number system allows limited carry and borrow propagation for addition and subtraction operations. In this paper, symmetrical and non-symmetrical special parallel recoding algorithms for the modified signed-digit numbers are proposed for carry-free arithmetic. Multi-bit parallel digital circuits are presented using AND-OR and/or OR-AND realizations. Also, transformation techniques between the proposed recoding algorithms are provided.

A simple one-step fully parallel trinary signed-digit arithmetic is proposed for parallel optical computing. This technique performs multidigit carry-free addition and borrow-free subtraction in constant time. The trinary signed-digit arithmetic operations are based on redundant bit representation of the digits. Optical implementation of the proposed arithmetic can be carried out using correlation or matrix multiplication based schemes. An efficient matrix multiplication based optical implementation that employs a fixed number of minterms for any operand length is developed. It is shown that only 30 minterms (less than recently reported techniques) are enough for implementing the one-step trinary addition and subtraction.

Commercial experiences have shown that involving users in the software design cycle is a cost-effective way of improving both the quality and the acceptability of tool products. This paper addresses the issue of whether users also should be involved in the research activities that lay the foundation for parallel tool design. Integrating users changes the basic nature of the software process in sev eral ways, as illustrated with examples from recent Parallel Tools Consortium projects. Tool designers must invest additional time to prepare example scenarios or proto types for user discussions, identify alternatives that can serve as points of departure for user-derived meta phors or models, and analyze user responses. By iden tifying user suggestions consistently throughout the de sign process, however, the development time for research prototypes is actually shortened.

A single-step optoelectronics symbolic substitution scheme to handle parallel modified signed-digit (MSD) arithmetic operations is proposed. Conversion algorithms from MSD numbers into a canonical MSD representation are provided. The canonical MSD numbers have the property that no two consecutive digits are non-zero. The addition operation of two CMSD numbers is performed in one step. It will be shown that through the use of CMSD representation, the number of symbolic substitution rules in an optical content-addressable memory (CAM) based system is significantly reduced. The number of symbolic substitution rules can be further reduced to an optimum value through a proposed shared content-addressable memory optical set-up. Further, the proposed optical scheme doubles the storage efficiency of the shared content-addressable memory.

In contrast to intensity-encoded negabinary modified signed-digit number representation, a polarization-encoding scheme is proposed to design all-optical adders. The adder circuits are designed using Terahertz-Optical-Asymmetric-Demultiplexer (TOAD) switches, polarization beam splitters, polarization converters, and beam combiners.

A higher radix based signed-digit number system, such as the quaternary signed-digit (QSD) number system, allows higher information storage density, less complexity, fewer system components, and fewer cascaded gates and operations. An optoelectronics symbolic substitution scheme to handle the parallel quaternary signed-digit (QSD) arithmetic operations is proposed. A conversion algorithm is employed on the QSD numbers to simplify the addition process and reduce the number of the optical symbolic substitution rules. The optical addition operation of two QSD numbers is performed in one-step. An efficient shared content-addressable memory (SCAM)-based optical implementation of the QSD addition/subtraction operations employs a fixed number of minterms for any operand length. The canonical QSD number addition/subtraction scheme requires a significantly reduced number of minterms when compared with a similar previously reported technique.

High-radix number representations such as the quaternary signed-digit (QSD) number system allow higher information storage density, less complexity, fewer system components, and fewer cascaded gates and operations. Arithmetic operations on the quaternary signed-digit are carried out using the powerful symbolic substitution scheme. A single-step or two-step conversion algorithm is employed on the QSD numbers to simplify the higher-order QSD addition process and reduce the number of the optical symbolic substitution rules. The optical addition operation of two QSD numbers is performed in one step. An efficient content-addressable memory (CAM) optical implementation of the QSD addition/subtraction operations is proposed. The QSD number addition/subtraction operations require a significantly reduced number of minterms (symbolic substitution rules) when compared to a similar previously reported technique.

This article offers practical, basic rules of thumb that can help you predict if parallelism might be worthwhile, given your application and the effort you want to invest. The techniques presented for estimating likely performance gains are drawn from the experiences of hundreds of computational scientists and engineers at national labs, universities, and research facilities. The information is more anecdotal than experimental, but it reflects the very real problems that must be overcome if parallel programming is to yield useful benefits.

A new approach to implement a compact all-optical MSD adder is reported using polarization-encoded SOA-MZI optical switches. The proposed adder requires 40% less optical switches compared to a recently reported adder.

In Interactive Learning Environments for conceptual knowledge, novice learners need support with understanding the used qualitative vocabulary, interpreting the simulation results, and knowing which modeling tasks can be performed. We explain how we generate support automatically, without making a priori assumptions regarding the domain knowledge involved. Assistance is contextualized and generated on the fly, even for complex models and simulations.

This study examined ZooQuest, a mobile game that supported fifth graders in the process of learning English as a second language. ZooQuest embedded the Mobile English Learning (MEL) application and was compared to MEL as a stand-alone application. Two groups were compared in a quasi-experimental pre- and posttest design. Fifth graders that used the ZooQuest application spent more time on learning at home than fifth graders that used the MEL application and obtained significant better learning results on the posttest than they did on the pretest. The ZooQuest application demonstrated its benefits in the practice of language learning outside school.

The input encoding algorithm of the polarization-encoded optical shadow-casting (POSC) scheme is modified to include the design of trinary combinational logic units. For illustration, the modified algorithm is deterministically employed in the design of trinary adders. Two design approaches are examined for identifying the constraints and flexibilities that are encountered depending on whether the zero-output conditions are considered. The more complicated POSC overlap equations are handled by incorporating LED source encoding to the input encoding process.

A general design algorithm is presented for the multioutput polarization-encoded optical shadow-casting scheme. A set of POSC equations is obtained from the truth table of the desired logic unit and is solved in terms of four possible pixel characteristics (transparent, opaque, vertically polarized, and horizontally polarized) and four possible source characteristics (off, unpolarized, vertically polarized, and horizontally polarized). To demonstrate its feasibility, the algorithm is used to determine the input pixel characteristics of a full adder and a full subtracter.

In this paper, designs of ultra-fast all-optical based Terahertz-optical-asymmetric-demultiplexer (TOAD)-based devices are reported. Using TOAD switches, adders/subtracters units are demonstrated. The high speed is achieved due to the use of the nonlinear optical materials and the nonbinary modified signed-digit (MSD) number representation. The proposed all-optical circuits are compared in terms of numbers TOAD switches, optical amplifiers and wavelength converters. Keywords: All-optical circuits, TOAD switches, nonbinary modified signed-digit, parallel computing. 1. INTRODUCTION To satisfy the increasingly needed operational speed in digital communication (in THz range) and optical/optoelectronics parallel processing systems, researcher s are switching from electronics to all-optical ones [1-12]. Recently, an all-optical switch whic h is capable of demultiplexing Tb/s pulse trai ns was reported [13, 14]. It consists of a nonlinear optical element asy mmetrically placed within a short fiber loop (TOAD), and operates with low-energy and it is small enough to be integrated on a chip. The TOAD switc h uses the nonlinearity in semiconductor optical amplifier (SOA) in a fiber interferometer to achieve ultrafast a ll optical demultiplexers and wavelength converters [. On the other hand, the need for higher computing power and processing speed is enforcing stringent demands on digital electronic computer systems. To achieve this dema nd, researchers look for non-conventional number system to carry fast arithmetic operations [15, 19]. The redundant signed-digit number system offers the possibility of carry-free arithmetic operations. One important property of the redundan t signed-digit representation is its carry-free propagation. Another important property is that both positive and negativ e weights are allowed in the representation without the use of 2's complement method. Recently, all-optical arithmetic operations based on TOAD switch are proposed [20, 21]. All-optical multiple logic gates with XOR, NOR, and NAND functions were reported usin g parallel TOAD structures as well as half-adder and full-adder. In this paper, the designs of ultra-fast all-optical TOAD -based device are reported. With the help of TOAD switches, adders units are demonstrated. The input an d the control signals are a ll-optical in nature. The high speed is achieved due to the use of the nonlinear optical materials and the nonbinary modified signed-digit (MSD) number representation. In contrast to the binary adder, the proposed circuits can be extended to n digit by employing additional stages without affecting the total addition time. Since the three MSD digits {-1, 0, 1} cannot be directly implemented using the two binary states of the TOAD switches, an encoding scheme is used to transform each MSD digits in to a pair of binary bits. Further, minimization technique is employed to the logical equations which leads to more efficient designs and more compact optical circuit in terms of numbers of logical gates, input/outputs lines, interconnection elements, and time delay units.

The logical equivalence between two powerful optical computing techniques, namely, optical symbolic substitution and optical shadow-casting is investigated. A common basis for both schemes is developed and their roots are traced back to fundamental principles of logic design. Both shadow-casting and symbolic substitution based optical computing operations are shown to be equivalent to logical sum of product operations.

Most of the algorithm proposed for face recognition involve considerable amount of computations and hence they cannot be used on devices constrained with limited memory. In this paper, we propose a novel solution for efficient face recognition for systems which are charactered with small memory devices and demand fast performance. By dividing the face images into components, the scheme finds the discriminant phases of the Fourier transform of these components of face images. The discriminant phases are found by using linear discriminant analysis (LDA) to obtain a system that matches the criteria imposed by devices of limited memory and requiring fast recognition. Note that since the effects of face variation within an image are reduced when the image is divided into components, then the performance of the system is enhanced. Compared to spatial domain analysis, it will be shown that the use of component in the frequency domain produces better recognition performance. A thorough study and comprehensive experiments relating time consumption and computational complexity versus system performance are presented. The proposed technique increases the face recognition rate and at the same time achieves substantial saving in the computational time, when compared to other known systems. The experimental results reveal that a recognition rate of ≥99% is achieved, when applied to two independent and well known databases.