The incorporation of fixed cost and multilevel capacities into the discrete and continuous single source capacitated facility location problem

In this study we investigate the single source location problem with the presence of several possible capacities and the opening (fixed) cost of a facility that is depended on the capacity used and the area where the facility is located. Mathematical models of the problem for both the discrete and the continuous cases using the Rectilinear and Euclidean distances are produced. Our aim is to find the optimal number of open facilities, their corresponding locations, and their respective capacities alongside the assignment of the customers to the open facilities in order to minimise the total fixed and transportation costs. For relatively large problems, two solution methods are proposed namely an iterative matheuristic approach and VNS-based matheuristic technique. Dataset from the literature is adapted to assess our proposed methods. To assess the performance of the proposed solution methods, the exact method is first applied to small size instances where optimal solutions can be identified or lower and upper bounds can be recorded. Results obtained by the proposed solution methods are also reported for the larger instances

A manpower allocation model of job specialization

A major copier machine company in Hong Kong presently faces the problem of providing effective servicing and repairing support to its four service regions. Due to the shortage of skilled technicians and the variety of jobs to be handled by technicians of differing skill levels, its Service Department appears to be understaffed, experiencing substantial daily backlogs. This study concentrates on a new perspective of operation: the assignment of technicians at each skill level to specialize in a single type of job in one of the four regions. The objective is to maximize the overall daily number of completed service calls. A mathematical model is developed to handle this specialized allocation problem, where the average travel time (forming part of the coefficient of one of the model's variables) of a technician servicing a type of job in a region is dependent on the decision variables - the composition of the whole team. This results in what we call a mixed integer non-linear programme with variable coefficients. An exact solution is obtained by an iterative algorithm with an overall dynamic programming approach. Sample numerical results are also reported.link_to_subscribed_fulltex

Hospital lift system simulator: A performance evaluator-predictor

Hospitals often experience lift congestion as a result of their heavy traffic, complex user types, and relatively slow-moving lifts (due to concerns over safety). Given the increasing number of current and new hospital building blocks that consist of many storeys, a visual simulation-based decision support system (DSS) is recommended. We present the modelling approach and development of a tool capable of being used for lift performance evaluation/prediction of existing/new hospital designs. These are also applicable to other general-purpose lift systems. A new data modelling approach, based on collected empirical traffic data, was developed to estimate the inter-floor passenger traffic. The DSS is flexible enough to allow the input of any zoning policy. The integrated zoning analysis offered here has not been found in existing lift simulators. This paper is the first to model a special feature designed to disable certain lift buttons in order to ensure fair use of the lift service. We carried out field studies of two existing hospitals, and we projected lift demand for a new hospital under construction. Performances at all three hospitals with different design structures under different operational control policies and lift features are given. © 2002 Elsevier Science B.V. All rights reserved.link_to_subscribed_fulltex

Fecal microbiota transplantation confers beneficial metabolic effects of diet and exercise on diet-induced obese mice

Diet and exercise are conventional methods for controlling body weight and are linked to alterations in gut microbiota. However, the associations of diet, exercise, and gut microbiota in the control of obesity remain largely unknown. In the present study, using 16S rRNA amplicon sequencing and fecal microbiota transplantation (FMT), normal fat diet (NFD), exercise and their combination resulted in improved metabolic profiles in comparison to sedentary lifestyle with high fat diet (HFD). Moreover, diet exerted more influence than exercise in shaping the gut microbiota. HFD-fed mice receiving FMT from NFD-exercised donors not only showed remarkably reduced food efficacy, but also mitigated metabolic profiles (p < 0.05). The transmissible beneficial effects of FMT were associated with bacterial genera Helicobacter, Odoribacter and AF12 and overrepresentation of oxidative phosphorylation and glycolysis genes. Our findings demonstrate that the beneficial effects of diet and exercise are transmissible via FMT, suggesting a potential therapeutic treatment for obesity