Improving system of distribution local railway junction in cars

Проведено аналіз перспективних напрямків удосконалення технології розвезення місцевих вагонів у залізничному вузлі. Виконано огляд наукових праць вітчизняних та зарубіжних вчених, що займаються тематикою вдосконалення та ефективного нормування передавального руху, оптимізації взаємодії та підвищення ефективності функціонування залізничних станцій у вузлах. В роботі поставлено завдання оптимізації розвозу місцевих вагонів у розвиненому залізничному вузлі. Складена залежність для визначення сумарного часу знаходження місцевого вагону у вузлі. Удосконалено математичну модель, алгоритм якої, незалежно від складності, конфігурації, кореспонденції та інших місцевих умов розвинених вузлів, дозволяє визначити оптимальне місце концентрації технічної роботи з місцевими вагонами відповідно до обраних параметрів та критеріїв оцінки.Проведен анализ перспективных направлений усовершенствования технологии развоза местных вагонов в железнодорожном узле. Выполнен обзор научных трудов отечественных и зарубежных ученых, которые занимаются тематикой совершенствования и эффективного нормирования передаточного движения, оптимизации взаимодействия и повышения эффективности функционирования железнодорожных станций в узлах. В работе поставлено задание оптимизации розвоза местных вагонов в развитом железнодорожном узле. Составленная зависимость для определения суммарного времени нахождения местного вагона в узле. Усовершенствована математическая модель, алгоритм которой, независимо от сложности, конфигурации, корреспонденции и других местных условий развитых узлов, позволяет определить оптимальное место концентрации технической работы с местными вагонами в соответствии с избранными параметрами и критериями оценки.The analysis promising areas of improvement technologies deliver a local carriages railway junction. A survey scientific works domestic and foreign scientists involved subjects Streamlining and standardization of gear movement, optimizing interaction and improve the efficiency railway stations in knots. In this paper, the task optimization local commercial cars in developed railway junction. Compiled dependence to determine the total time spent in the local car site. Improved mathematical model, an algorithm which, regardless of complexity, configuration, correspondence and other local conditions developed nodes to determine optimum concentration technical work with local cars according to selected parameters and benchmarks. Analysis local circulation vahonopotoku showed that most time the car is idle for trucks and industrial plants. Given the above, it can be argued that the current development industry and research necessary technologies of local coaches in major junctions

Suitability and managerial implications of a Master Surgical Scheduling approach

Abstract: Operating room (OR) planning and scheduling is a popular and challenging subject within the operational research applied to health services research (ORAHS). However, the impact in practice is very limited. The organization and culture of a hospital and the inherent characteristics of its processes impose specific implementation issues that affect the success of planning approaches. Current tactical OR planning approaches often fail to account for these issues.Master surgical scheduling (MSS) is a promising approach for hospitals to optimize resource utilization and patient flows. We discuss the pros and cons of MSS and compare MSS with centralized and decentralized planning approaches. Finally, we address various implementation issues of MSS and discuss its suitability for hospitals with different organizational foci and culture

A Survey of Experimental Research on Contests, All-Pay Auctions and Tournaments

Many economic, political and social environments can be described as contests in which agents exert costly efforts while competing over the distribution of a scarce resource. These environments have been studied using Tullock contests, all-pay auctions and rankorder tournaments. This survey provides a review of experimental research on these three canonical contests. First, we review studies investigating the basic structure of contests, including the contest success function, number of players and prizes, spillovers and externalities, heterogeneity, and incomplete information. Second, we discuss dynamic contests and multi-battle contests. Then we review research on sabotage, feedback, bias, collusion, alliances, and contests between groups, as well as real-effort and field experiments. Finally, we discuss applications of contests to the study of legal systems, political competition, war, conflict avoidance, sales, and charities, and suggest directions for future research. (author's abstract

Evaluating the effect of sub-optimality

Comparison of a sub-optimal solution with an optimal, possibly time-consuming to find, solution has crucial importance in Operations Management. In this note, we highlight the potential underestimation of the effect of sub-optimality in recent studies and propose to use an alternative measure for comparing the quality of optimal solutions with sub-optimal ones. We give examples from the realm of Inventory Pooling and the “Price of Anarchy” in supply chains

Inventory sharing via circular bidirectional chaining

We investigate a lean inventory sharing strategy, called “Circular Bidirectional Chaining” (BDC), in a single period setting, and quantify the difference between the performance of BDC and the performance of other inventory sharing strategies for normally distributed demands. Under BDC all the locations, each facing stochastic demand, are connected in a closed loop, such that each location is allowed to cooperate laterally with exactly two adjacent locations. A location is not allowed to serve as a source and a sink of material at the same time. To consider BDC vis-à-vis other strategies, one must first optimize the proposed BDC strategy. Managing the BDC consists of two problems: determining the optimal order quantities, and, for given order quantities and demand realizations, determining how should items be transshipped. The former is a stochastic planning problem with recourse, solved via simulation-based optimization, while the latter, which is the recourse part of the former, can be interpreted as a transportation problem. Sensitivity analysis with respect to problem parameters is provided. It turns out that BDC can achieve a considerable portion of the benefits of complete pooling in around 65% of the cases, while the cost required to enable cooperation via BDC is lower than that of complete pooling

Multidimensional assortment problem with an application

This paper addresses the discrete multidimensional assortment problem. Assortment issues arise frequently in practice as an important design and inventory problem which simultaneously seeks the answers to two related questions: (a) Which items (or sizes of a product) to stock? (b) How much of each to stock? its discrete multidimensional version concerns itself with choosing sizes from among a discrete set of possible ones with each size being characterized by more than one dimension. Our research is motivated by an application of the problem in the distribution center of a global manufacturer of telecommunications equipment where the goal was to standardize the sizes of three-dimensional crates used to package finished items by selecting a few from among all crate sizes. The main contributions of this research are (1) modeling the assortment problem as a facility location problem, (2) devising a heuristic procedure that generates a good solution to the problem as well as a bound on the optimal solution, and (3) implementing the heuristic procedure on a PC so as to obtain solutions for actual large-scale instances of a three-dimensional problem. (C) 1999 John Wiley & Sons, Inc