bluuebunny/crossref_metadata_2025_split huggingface dataset:
Serial changes in the high‐frequency ECG during the first year following acute myocardial infarction
Authors: Trägårdh Elin , Pahlm Olle , Hedén Bo , Sörnmo Leif , Tägil Kristina , Wagner Galen S. , Pettersson Jonas 
Published: August 2006

SummaryBackground:  Previous studies have shown reduced high‐frequency QRS components (HF‐QRS) after acute myocardial infarction (MI). The purpose of this study was to investigate serial changes in HF‐QRS during the first year following acute MI.Methods:  A total of 75 patients were included. Standard‐ and high‐frequency ECGs were recorded on five occasions during the year following the MI (a few days after the MI, after 6 weeks, and after 3, 6 and 12 months).Results:  There was a statistically significant increase in HF‐QRS during the follow‐up year (P = 0·002). There were no significant differences in HF‐QRS when comparing either the infarct location or the presence or absence of reperfusive therapy. Large differences in HF‐QRS were observed, both intra‐individually and inter‐individually, during the year.Conclusions:  There was a statistically significant increase in HF‐QRS during the year following acute MI.
Short‐term resistance training and the older adult: the effect of varied programmes for the enhancement of muscle strength and functional performance
Authors: Henwood Tim R. , Taaffe Dennis R. 
Published: August 2006

SummaryAlthough it is well recognized that resistance training is an efficient strategy to enhance physical performance in older adults, less is known about the most effective type of resistive exercise or the role of functional training. This study compared the effectiveness of three varied short‐term (8 weeks) training protocols on muscle strength and functional performance in older men and women aged 65–84 years. Participants underwent twice‐weekly high‐velocity varied‐resistance training (HV), twice weekly slow to moderate‐velocity constant‐resistance training (CT), combined once weekly high‐velocity varied‐resistance and once weekly gymnasium‐based functional training (CB) or no training (CO). Dynamic muscle strength (1RM) of six muscle groups was assessed using isotonic equipment and functional performance by a battery of tests. Following 8 weeks of training, whole‐body muscle strength increased (P<0·001) by 22·0 ± 12·5% (mean ± SD), 21·7 ± 11·0% and 26·1 ±14·4% in HV, CT and CB, respectively, compared to CO (−1·8 ± 7·2%). In between group comparisons, only the HV group displayed greater chair rise ability (P =0·010) than the CO group, while differences among groups approached significance for the fast 6‐m walk and the stair climb test (P = 0·017 and 0·041 respectively). Within groups, the HV group significantly improved in stair‐climbing and chair rise ability (P≤0·001) while CB improved in the fast 6‐m walk (P = 0·003) and CT improved their static balance, as assessed by the functional reach test (P<0·001). This study indicates that twice weekly high‐velocity resistance training is superior to strength and combined functional and resistance training for improving some power‐orientated functional tasks. Although other functional performance improvements were modest among the training protocols, short‐term combined once weekly resistance and once weekly functional training in older adults was as effective in enhancing muscle strength as twice‐weekly resistance training. These results have important implications for older adults who are unable or unwilling to frequently attend exercise facilities.
A Fuzzy Approach to Preference Structure in Multicriteria Ranking
Authors: Radojevic A. , Petrovic S. , Radojevic D. 
Published: August 2006

The family of Promethee methods for multicriteria ranking of a finite set of alternatives is well known in literature and used in practice. In order to express her/his preference structure the decision maker is asked to select, for each criterion, a preference function from a predefined set. It is a function that maps differences between criterion values of pairs of alternatives into interval [0,1]. For each preference function, the decision maker has to fix parameters that define indifference and strict preference areas.A weak point in Promethee methods is that imprecision in judgment of preference functions is handled by relatively simple and rigid mathematical artifacts. We propose fuzzy sets theory and associate approximate reasoning as an appropriate framework to imitate human reasoning in expressing a preference structure. For each criterion, the decision maker uses linguistic terms ‘small difference’, ‘medium difference’, and ‘big difference’, which enable him/her to express his/her preference structure in a linguistic and thus more natural way. These descriptors interpret the system of decision maker's values and are context dependent. We introduce fuzzy IF‐THEN rules that relate the difference of criterion values to the preference function. The proposed modification extends the applicability of Promethee methods significantly, because it enables ranking of alternatives in the case when criteria values are fuzzy variables. The corresponding software is developed and tested on a number of examples.
Information effects on commuters' behavior under varying network patronage
Authors: Sinuany‐Stern Z. , Stern E. , Spharadi Z. 
Published: August 2006

AbstractThe present paper presents one aspect of a more comprehensive study which estimated the possible effects of information presented to commuting drivers on their choice behavior, and thus on the whole network performance. This research shows that the contribution of congestion‐related information decreases as the number of drivers using the information increases, the effect of information on behavioral decisions is examined here in relation to network performance.
A framework for developing a daily activity and multimodal travel planner
Authors: Vaughn K.M. , Abdel‐Aty M.A. , Kitamura R. 
Published: August 2006

AbstractThere is a need to further explore ways to use Advanced Traveler Information Systems (ATIS) to encourage transit and ridesharing. One mechanism is to provide convenient travel itinerary information, not just for one trip, but for a day's travel. The formulation should consider time constraints, activity needs, real transit service parameters and the actual street system. Basic algorithmic development is needed to spur the private sector interest in such a product by demonstrating its utility. The activity travel planner will aid its user in planning his daily itinerary by arranging the sequence of stops, suggesting and possibly selecting stop locations, providing transit route and schedule information, and suggesting travel routes. This paper develops a framework for solving the Travel Itinerary Planning Problem (TIPP) which is a variant of the Traveling Salesman Problem (TSP). Implementation of the solution algorithm would be used to develop and test a prototype for an activity and travel planner.
Simulation assisted design and assessment of vehicle guidance systems
Authors: Barceló J. , Ferrer J.L. , Martín R. 
Published: August 2006

AbstractThis paper presents the description and results obtained using prototypes of two simulators purposely built to assist the design and assessment of vehicle guidance systems, namely those based on cellular radio communication technology. These tools have been used to examine the benefits of dynamic route guidance systems compared to static ones, to investigate the stability of the recommended routes with respect to changes in link travel times, the efficiency of the data collection procedures from the equipped vehicles, and the overheads on the telecommunications channels.
Experiential learning activities in Operations Management
Authors: Ammar S. , Wright R. 
Published: August 2006

AbstractThis paper describes eight in‐class activities that have been effectively used to complement the traditional theoretical presentation in an introductory operation and production management course in either an undergraduate or graduate program. For each activity we include the course topics the activity supports, a description of the activity and an evaluation of its effectiveness based on our experience. The activities include physically played games as well as computer simulations. Most are easily adaptable to different courses and teaching styles.
An energy planning approach based on mixed 0–1 Multiple Objective Linear Programming
Authors: Mavrotas G. , Diakoulaki D. , Papayannakis L. 
Published: August 2006

AbstractMultiple Objective Linear Programming (MOLP) models have been widely used in the energy sector for taking into account several conflicting objectives pursued in energy planning. However, continuous variables are not suffcient to accurately represent discrete phenomena encountered in many practical decision situations, such as the power generation expansion problem. This paper presents a new approach based on a mixed 0–1 MOLP model and applied to the Greek electricity generation sector for identifying the number and output of each type of power units needed to satisfy the expected electricity demand in the future. The core of the model is a branch and bound algorithm, which has been properly modified for the multi‐objective case and is capable of generating the whole set of effcient solutions. The results provided by this method is the extraction of the effcient combinations of the power generation units, and for each combination the effcient solutions determining electricity production from each unit.
Time–cost evaluation of alternative system/process designs
Authors: Shaftel T.L. , Wilson B.M. 
Published: August 2006

AbstractTechniques for representing system/process designs are a common feature of most design methodologies. These techniques can be enhanced to provide valuable information regarding a specific design structure's trade‐off between task completion times and cost. In this paper, we present a mathematical model and a solution algorithm which can be used to upgrade any well‐structured representation technique to provide this trade‐off. Having this information readily available allows a design team to focus on less quantifiable features of specific designs, thereby improving the overall design process.
IA supported synchronous digital hierarchy transport network planning
Authors: Romão Cavati C. 
Published: August 2006

AbstractThis paper introduces a methodology for carrying out Transport Networks Synchronous Digital Hierarchy (TN‐SDH) planning, when the objective is the definition of routing fiber optics cables in existing galleries. The proposed methodology employs mathematical programming models in which the traffic matrix is represented by means of fuzzy set concepts, its uncertainties considered due to the existence of various and sophisticated telecommunication services in its networks. The TN‐SDH planning is understood as a problem of multicommodity flow networks and the model obtained has a fuzzy linear programming characteristic. This procedure was applied in a large‐scale realistic network and the results show that it is a method which is more attractive than others and do not employ fuzzy set in modeling the knowledge of traffic matrix.
The effectivity of new traffic‐technologies and transportation‐systems in suburban areas and on motorways
Authors: Ludmann J. , Neunzig D. , Weilkes M. , Wallentowitz H. 
Published: August 2006

AbstractAt the Forschungsgesellschaft Kraftfahrwesen mbH Aachen (fka) the submicroscopic traffic simulation program PELOPS (Program for the dEvelopment of Longitudinal micrOscopic traffic Processes in a Systemrelevant environment) was developed in co‐operation with the BMW AG. It simulates the traffic flow on motorways with a specific view on vehicle affairs. One application for PELOPS was the assessment of ACC (Adaptive Cruise Control) systems inside the PROMETHEUS program. A new research period extends the use of ACC about the functionality to urban areas. This requires an extension of PELOPS to include some specific models. With this extension, it is possible to analyse new traffic technologies for individual vehicles or infrastructure. Based on detailed traffic measurements, different scenarios are simulated to improve the traffic flow and to relieve the environment. These scenarios include ACC systems, inter‐vehicle‐communication and intelligent traffic lights. Another actual application is the analysis of the influence of new road trains (extra‐long trucks with increased speed and enhanced breaking‐capabilities) on traffic‐flow and driving safety on German motorways. The paper gives detailed information about the simulation techniques and the results of the current analysis.
Optimal fleet design in a ship routing problem
Authors: Fagerholt K. 
Published: August 2006

AbstractThe problem of deciding an optimal fleet (the type of ships and the number of each type) in a real liner shipping problem is considered. The liner shipping problem is a multi‐trip vehicle routing problem, and consists of deciding weekly routes for the selected ships. A solution method consisting of three phases is presented. In phase 1, all feasible single routes are generated for the largest ship available. Some of these routes will use only a small portion of the ship's capacity and can be performed by smaller ships at less cost. This fact is used when calculating the cost of each route. In phase 2, the single routes generated in phase 1 are combined into multiple routes. By solving a set partitioning problem (phase 3), where the columns are the routes generated in phases 1 and 2, we find both the optimal fleet and the coherent routes for the fleet.
Job sequencing with uncertain and controllable processing times
Authors: Adamopoulos G.I. , Pappis C.P. , Karacapilidis N.I. 
Published: August 2006

AbstractIn this paper, a single machine scheduling problem is considered. The jobs' processing times are controllable (i.e., they may take any value within a certain range) and non‐precisely defined. They are treated as linguistic variables, whose values are expressed by means of fuzzy numbers. The objective function to be minimised is: (a) the mean flow time cost plus the mean processing cost, and (b) the maximum flow time cost plus the total processing cost. The problem is modelled as an assignment problem and is solved optimally with respect to the defuzzification strategy used.
Towards hybrid evolutionary algorithms
Authors: Preux P. , Talbi E.‐G. 
Published: August 2006

AbstractMetaheuristics have received considerable interest these recent years in the field of combinatorial optimization. However, the choice of a particular algorithm to optimize a certain problem is still mainly driven by some sort of devotion of its author to a certain technique rather than by a rationalistic choice driven by reason. Hybrid algorithms have shown their ability to provide local optima of high quality. Hybridization of algorithms is still in its infancy: certain combinations of algorithms have experimentally shown their performance, though the reasons of their success is not always really clear. In order to add some rational to these issues, we study the structure of search spaces and attempt to relate it to the performance of algorithms. We wish to explain the behavior of search algorithms with this knowledge and provide guidelines in the design of hybrid algorithms. This paper briefly reviews the current knowledge we have on search spaces of combinatorial optimization problems. Then, we discuss hybridization and present a general classification of the way hybridization can be conducted in the light of our knowledge of the structure of search spaces.
A self‐organizing neural network approach for multiple traveling salesman and vehicle routing problems
Authors: Modares A. , Somhom S. , Enkawa T. 
Published: August 2006

AbstractThis paper addresses several algorithms based on self‐organizing neural network approach for routing problems. The algorithm for Traveling Salesman Problem is elaborated and the extension of the proposed algorithm to more complex problems namely, Multiple Traveling Salesmen and Vehicle Routing is discussed. In order to investigate the performance of the algorithms, a comprehensive empirical study has been provided. The simulations, which are conducted on standard data, evaluate the overall performance of this approach by comparing the results with the best known or the optimal solutions of the problems. The proposed algorithm shows significant advances in both qualities of the solution and computational efforts for most of the experimented data.
Approximating minimum spanning tree of depth 2
Authors: Alfandari L. , Paschos V.T. 
Published: August 2006

AbstractWe prove that the problem of finding, in an undirected graph with non‐negative costs on edges, a minimum cost rooted spanning tree of depth 2 is NP‐hard. We then prove that, in a graph of ordern, this problem cannot be approximated within better thanO)lnn), unless problems in NP can be solved by slightly superpolynomial algorithms. We also prove that the metric version of the problem is MAX‐SNP‐hard and, consequently, cannot be approximated by polynomial time approximation schemes, unless P=NP. We devise approximation algorithms for several restricted cases and, finally, a polynomial time algorithm approximating the general problem within ratio lnn.
An adaptive tabu search algorithm for the capacitated clustering problem
Authors: França P.M. , Sosa N. M. , Pureza V. 
Published: August 2006

AbstractIn the Capacitated Clustering Problem, a given set of customers with distinct demands must be partitioned into p clusters with limited capacities. The objective is to find p customers, called medians, from which the sum of the distances to all other customers in the cluster is minimized. In this article, a new adaptive tabu search approach is applied to solve the problem. Initial solutions are obtained by four constructive heuristics that use weights and distances as optimization criteria. Two neighborhood generation mechanisms are used by the local search heuristic: pairwise interchange and insertion. Computational results from 20 instances found in the literature indicate that the proposed method outperforms alternative metaheuristics developed for solving this problem.
Solving multiple objective quasi‐convex goal programming problems by linear programming
Authors: Li H‐L. , Yu C‐S. 
Published: August 2006

AbstractThis study presents a novel means of resolving multiple objective goal programming (GP) problems with quasi‐convex linear penalty functions. The proposed method initially expresses a quasi‐convex function by the maximum operator of two convex functions, then solves it via a linear programming technique. The proposed method does not contain any zero–one variables; nor does it require dividing the multi‐objective quasi‐convex GP problem into large sub‐problems as in conventional methods. Some illustrative examples are provided.
Classical and modern heuristics for the vehicle routing problem
Authors: Laporte G. , Gendreau M. , Potvin J‐Y. , Semet F. 
Published: August 2006

AbstractThis article is a survey of heuristics for the Vehicle Routing Problem. It is divided into two parts: classical and modern heuristics. The first part contains well‐known schemes such as, the savings method, the sweep algorithm and various two‐phase approaches. The second part is devoted to tabu search heuristics which have proved to be the most successful metaheuristic approach. Comparative computational results are presented.
Very large‐scale neighborhood search
Authors: Ahuja R.K. , Orlin J.B. , Sharma D. 
Published: August 2006

AbstractNeighborhood search algorithms are often the most effective approaches available for solving partitioning problems, a difficult class of combinatorial optimization problems arising in many application domains including vehicle routing, telecommunications network design, parallel machine scheduling, location theory, and clustering. A critical issue in the design of a neighborhood search algorithm is the choice of the neighborhood structure, that is, the manner in which the neighborhood is defined. Currently, the two‐exchange neighborhood is the most widely used neighborhood for solving partitioning problems. The paper describes the cyclic exchange neighborhood, which is a generalization of the two‐exchange neighborhood in which a neighbor is obtained by performing a cyclic exchange. The cyclic exchange neighborhood has substantially more neighbors compared to the two‐exchange neighborhood. This paper outlines a network optimization based methodology to search the neighborhood efficiently and presents a proof of concept by applying it to the capacitated minimum spanning tree problem, an important problem in telecommunications network design.
Analysis of a ring‐based loss network
Authors: Thompson M. 
Published: August 2006

AbstractLoss networks are a class of resource allocation models which have proved useful in the study and design of communication networks. A major aim when analysing these models is to obtain measures of performance such as congestion probabilities and throughput. Even for moderately sized networks it is often not possible to calculate the quantities of interest exactly in reasonable time. Accordingly there is motivation to investigate methods of accurate approximation. This paper is concerned with estimating the performance measures of a ring‐shaped network with branches. Two methods are presented: an asymptotic analysis made possible by the network's cyclic structure, and a technique utilising the network's symmetry which could be applied more generally.
Heuristic approaches to the asymmetric travelling salesman problem with replenishment arcs
Authors: Mak V. , Boland N. 
Published: August 2006

AbstractThe Asymmetric Travelling Salesman Problem with Replenishment Arcs (RATSP) is a new class of problem arising from work related to aircraft routing. This paper describes the problem and presents heuristic approaches for solving the RATSP. We use simulated annealing to obtain feasible solutions, and hence, upper bounds on the optimum value, and solve a Lagrangean dual problem using a subgradient optimization method to obtain lower bounds. While previous methods failed to obtain optimal solutions to some problem classes after 2 h of computation time, with average gaps ranging from 15% to 30%, our heuristic approaches take only 15–20 min to obtain feasible solutions, with gaps of less than 3%. We give computational results comparing these approaches.
Simulation in public sector management: a case study
Authors: Hays M‐A. , Bebbington M. 
Published: August 2006

AbstractWe detail the development and application of a simulation model to aid decision making concerning the procedures followed in the Office of Film and Literature Classification, by forecasting the effects of possible management initiatives. The major variables are — the number of censors, the volume of publications to be classified (with special emphasis on computer technology publications) and the procedures, in particular, the number of censors with decision‐making powers. A model of the system was developed using Extend; a simulation software package designed to aid decision support. This model was used to investigate the utilization of “decision‐makers”, and to identify and locate the bottlenecks, in the system under a number of different scenarios suggested by the client. There is also the flexibility to include additional duties that might be imposed on the Office.