749 research outputs found

    A Survey of the Routing and Wavelength Assignment Problem

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    On the Integrated Job Scheduling and Constrained Network Routing Problem

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    This paper examines the NP-hard problem of scheduling a number of jobs on a finite set of machines such that the overall profit of executed jobs is maximized. Each job demands a number of resources, which must be sent to the executing machine via constrained paths. Furthermore, two resource demand transmissions cannot use the same edge in the same time period. An exact solution approach based on Dantzig-Wolfe decomposition is proposed along with several heuristics. The methods are computationally evaluated on test instances arising from telecommunications with up to 500 jobs and 500 machines. Results show that solving the problem to optimality is very difficult. The proposed heuristics have good performance with an average solution value gap of 3% and with very small running times

    Greedy and metaheuristics for the offline scheduling problem in grid computing

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    In grid computing a number of geographically distributed resources connected through a wide area network, are utilized as one computations unit. The NP-hard offline scheduling problem in grid computing consists of assigning jobs to resources in advance. In this paper, five greedy heuristics and two metaheuristics for solving the offline scheduling problem are introduced. Computationally evaluating the heuristics shows that all heuristics find useful solutions with a gap of 20\% between upper and lower bounds. The metaheuristics give better results than the greedy heuristics, but also have larger time usage. All heuristics solve instances with up to 2000 jobs and 1000 resources, thus the results are useful both with respect to running times and to solution values

    Foreword

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    Foreword by Frederick C. Gams

    Toward a Method of Industrial Ethnology

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    Paper by Frederick C. Gams

    Oral assessment in the English subject

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    This study investigates how teachers of English assess oral competence at lower secondary schools in Norway. Previous studies (Svenkerud, 2013, Hertzberg, 2012, Bøhn, 2015) point to oral presentations as the main method used for oral assessment, and the assessment given varies because of the subjective nature of oral assessment. It is also assumed that teachers disagree on how oral assessment should be done, and I imagine that they find oral assessment more difficult than written assessment. Therefore, this thesis investigates teachers’ practices of oral assessment. The research question is as followed: How do teachers assess oral skills in lower secondary schools in Norway? In order to answer this question, I have used a mixed-method approach consisting of a questionnaire and an interview. A questionnaire with 139 participants was used to gather data that could show general practices in assessing. An interview guide was developed based on the data collected from the questionnaire. An interview was conducted with three informants. All the informants teach at lower-secondary schools in Norway. My findings indicate that teachers vary in what method they use and what aspects they focus on during oral assessment. Although most teachers use oral presentation as a form of assessing oral competence, it is not the only form of assessment. Teachers do not think there is a common understanding nationally as to how oral skills should be assessed. Moreover, my findings show that there is a common belief among teachers that there is a need for clearer criteria or a common rating scale for oral assessment
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