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  • 1
    ISSN: 1432-1971
    Keywords: ECG normal standards, children ; ECG age evolution ; Computer ECG measurements
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Normal ECG values were determined using computer-assisted measurement of the ECGs of 2,141 white children aged 0 to 16 years divided into 12 age groups. These values are plotted on graphs containing the second, fifth, 25th, 50th, 75th, 95th, and 98th percentiles for each age group. This provides a convenient, fast, and practical method for comparing the values found in a given ECG with those found in a normal population, taking into account the evolution of ECG patterns with age.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Annals of operations research 69 (1997), S. 135-156 
    ISSN: 1572-9338
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics , Economics
    Notes: Abstract We propose a dynamic programming algorithm for the single machine scheduling problem with ready times and deadlines to minimize total weighted completion time. Weights may be positive or negative and the cost function may be non-regular. This problem appears as a subproblem in the Dantzig-Wolfe decomposition of the job-shop scheduling problem. We show that the algorithm is polynomial if time window length is bounded by a constant and times are integer-valued. We present computational results for problems with up to 200 jobs.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    International journal of flexible manufacturing systems 10 (1998), S. 27-42 
    ISSN: 1572-9370
    Keywords: flexible manufacturing ; strip sequencing strategies ; tool partitioning ; Manhattan and Chebychev metrics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The purpose of this paper is to develop optimal tool partitioning policies and strip sequencing strategies for a class of flexible manufacturing problems. The problems under consideration involve a large number of operations to be performed by a series of tools on a two-dimensional object. For example, these operations could consist of drilling holes in a metallic sheet. Tools are arranged in a carousel or along a toolbar according to a predetermined sequence. Operations are performed by repeatedly moving the sheet to bring the hole locations under the tool. During each pass, as all operations involving a series of consecutive tools are executed, two main problems are to be solved: (1) how to move the sheet during each pass, (2) how to partition the tools into blocks of consecutive tools. A strip strategy is used to move the sheet. Given this policy, optimal strip widths and tool partitioning policies are determined jointly. Analytical solutions are derived under two metrics corresponding to different operating modes. A numerical example is provided.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    International journal of flexible manufacturing systems 6 (1994), S. 123-135 
    ISSN: 1572-9370
    Keywords: strip strategies ; flexible manufacturing ; traveling salesman problem
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract In this paper, optimal strip strategies are developed for a variety of two-dimensional and three-dimensional sequencing problems arising in flexible manufacturing. These strategies are appropriate for CNC drilling operations, NC punching operations, and circuit board population, for example. Seven different metrics are considered.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    International journal of flexible manufacturing systems 7 (1995), S. 5-26 
    ISSN: 1572-9370
    Keywords: cell configuration ; cycle time ; linear programming method ; longest path method ; movement network ; movement schedule (cycle) ; part input sequence ; sequence processing time ; waiting time
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract In this paper, we analyze the efficiency of a given robot movement schedule for the case of a flow shop robotic production cell withm different machines, one input conveyor, and one output conveyor. We begin with the case of one-robot cells and extend our results to multirobot cells. The paper studies the efficiency of a movement schedule for identical parts by defining a movement network associated with this schedule. This network models any cell layout and applies to multirobot cells. Using the movement network, we propose two cycle time evaluation methods, the first using linear programming and the second based on finding a longest path. The latter method generates a procedure to obtain an analytical formula for the cycle time. We extend the proposed methods to study the efficiency of a given input sequence (schedule) for different parts, that is, to determine the sequence processing time. The results obtained here allow us to quickly evaluate the efficiency of any given feasible movement schedule, for identical or different parts.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Telecommunication systems 1 (1993), S. 133-148 
    ISSN: 1572-9451
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Abstract With the advent of non-hierarchical routing in circuit-switched telecommunication networks, on-line routing policies have been developed with the objective of optimizing some measure of gain or performance. These policies are decentralized. However, traditional planning models are centralized models. We present a decentralized routing model to be used in network planning. We compare it theoretically and empirically with a centralized multicommodity flow model previously presented. The two models are solved by the same type of algorithm, a convex simplex implementation, adapted differently according to the model. Comparative results between planning models reproducing the two policies are discussed.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Telecommunication systems 1 (1993), S. 149-177 
    ISSN: 1572-9451
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Abstract We present a theoretical study of a modified version of the dimensioning problem for telephone networks where the network does not contain any existing capacity and where the available capital is severely limited, a situation which can occur in private networks as well as in the public networks of developing countries. In the latter, case, the budget constraint is generally of paramount importance. This has two effects. First, the grade of service constraint is replaced by a budget constraint. Another difference from the original problem arises because the network may be operating under overload most of the time. This paper examines some cases of overload for which the link ordering is maintained. The main result of this paper is the derivation of a set of equations similar to the classical optimality equations that lead to the ECCS method, but for the modified version of the problem. As a consequence, we expect that it will be possible to obtain a fast iterative heuristic algorithm similar to the one currently used to solve the classical problem. A number of other points of theoretical interest are also discussed, mainly with the objective of gaining insight into the structure of the modified problem.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Annals of operations research 36 (1992), S. 263-274 
    ISSN: 1572-9338
    Keywords: Network dimensioning ; telecommunications ; reliability ; circuit switching ; routing
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics , Economics
    Notes: Abstract In this paper we introduce a new methodology to adjust link capacities in circuit switched networks taking into account the costing policy and reliability considerations. This methodology, which is an extension of previous work on reliability evaluation using routing models, is based on a cyclic decomposition algorithm which alternates between a routing subproblem and a link capacity adjustment subproblem. The proposed procedure, which is shown to converge to a global optimum for the dimensioning/routing problem, has been tested on a 14 undirected arc problem for various levels of link failure probability. The numerical results are extremely satisfactory and they demonstrate the usefulness of the proposed method for proper network dimensioning.
    Type of Medium: Electronic Resource
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  • 9
    Publication Date: 2020-08-05
    Description: The tail assignment problem is a critical part of the airline planning process that assigns specific aircraft to sequences of flights, called lines-of-flight, to be operated the next day. The aim of this paper is to develop an operationally flexible tail assignment that satisfies short-range---within the next three days---aircraft maintenance requirements and performs the aircraft/flight gate assignment for each input line-of-flight. While maintenance plans commonly span multiple days, the related tail assignment problems can be overly complex and provide little recourse in the event of schedule perturbations. The presented approach addresses operational uncertainty by extending the one-day routes aircraft maintenance routing approach to satisfy maintenance requirements explicitly for the current day and implicitly for the subsequent two days. A mathematical model is presented that integrates the gate assignment and maintenance planning problems. To increase the satisfaction of maintenance requirements, an iterative algorithm is developed that modifies the fixed lines-of-flight provided as input to the tail assignment problem. The tail assignment problem and iterative algorithm are demonstrated to effectively satisfy maintenance requirements within appropriate run times using input data collected from three different airlines.
    Language: English
    Type: reportzib , doc-type:preprint
    Format: application/pdf
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  • 10
    Publication Date: 2020-08-05
    Description: Aircraft maintenance planning is of critical importance to the safe and efficient operations of an airline. It is common to solve the aircraft routing and maintenance planning problems many months in advance, with the solution spanning multiple days. An unfortunate consequence of this approach is the possible infeasibility of the maintenance plan due to frequent perturbations occurring in operations. There is an emerging concept that focuses on the generation of aircraft routes for a single day to ensure maintenance coverage that night, alleviating the effects of schedule perturbations from preceding days. In this paper, we present a novel approach to ensure that a sufficient number of aircraft routes are provided each day so maintenance critical aircraft receive maintenance that night. By penalising the under supply of routes terminating at maintenance stations from each overnight airport, we construct a single day routing to provide the best possible maintenance plan. This single day aircraft maintenance routing problem (SDAMRP) is further protected from disruptions by applying the recoverable robustness framework. To efficiently solve the recoverable robust SDAMRP acceleration techniques, such as identifying Pareto-optimal cuts and a trust region approach, have been applied. The SDAMRP is evaluated against a set of flight schedules and the results demonstrate a significantly improved aircraft maintenance plan. Further, the results demonstrate the magnitude of recoverability improvement that is achieved by employing recoverable robustness to the SDAMRP.
    Language: English
    Type: article , doc-type:article
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