• Title/Summary/Keyword: Closest Assignment Rule

Search Result 3, Processing Time 0.019 seconds

Capacitated Location and Allocation Models of Long-Term Care Facilities

  • Song, Byung Duk;Ko, Young Dae;Morrison, James R.;Hwang, Hark
    • Industrial Engineering and Management Systems
    • /
    • v.12 no.3
    • /
    • pp.190-197
    • /
    • 2013
  • People are living longer than ever before. As a result, life expectancy is going up and the demand of long-term care facilities is increasing in most countries. The facilities provide rehabilitative, restorative, and skilled nursing care to patients or residents in need of assistance with activities of daily living. This study deals with the capacitated location and allocation problem of long-term care facilities in a city that consists of a finite number of regions. Assuming that in each region candidate locations for three types of facilities are already given, two integer programming models are developed under the closest assignment rule reflecting the demand characteristics of the facilities. Both the location and type of the facilities to be built become decision variables. To show the validity of the models, numerical problems are solved with commercial software, CPLEX. Also, sensitivity studies were conducted to identify relationships between the system parameters.

A Simulation Study on the Determination of Storage Location in Automated Warehousing Systems (자동창고 시스템의 저장위치 선정에 관한 시뮬레이션 연구)

  • Sohn, Kwon-Ik;Kim, Chang-Deog;Cho, Yong-Hwan
    • Journal of Industrial Technology
    • /
    • v.14
    • /
    • pp.49-61
    • /
    • 1994
  • This study deals with the automated storage/retrieval systems (AS/RS) where the rack is discrete and the random storage assignment rule is adopted. New storage policies named FNSC (first no-cost zone, second closest-open location) and FNSH (first no-cost zone, second a half side closest-open location) are proposed. Simulation results indicate that performance of FNSH is slightly lower than that of the SCL but it does not need much time to perform. The "stay" strategy of S/R machine is examined as a means of increasing the frequency of dual command.

  • PDF

Study on the Evaluation of Ship Collision Risk based on the Dempster-Shafer Theory (Dempster-Shafer 이론 기반의 선박충돌위험성 평가에 관한 연구)

  • Jinwan Park;Jung Sik Jeong
    • Journal of the Korean Society of Marine Environment & Safety
    • /
    • v.29 no.5
    • /
    • pp.462-469
    • /
    • 2023
  • In this study, we propose a method for evaluating the risk of collision between ships to support determination on the risk of collision in a situation in which ships encounter each other and to prevent collision accidents. Because several uncertainties are involved in the navigation of a ship, must be considered when evaluating the risk of collision. We apply the Dempster-Shafer theory to manage this uncertainty and evaluate the collision risk of each target vessel in real time. The distance at the closest point approach (DCPA), time to the closest point approach (TCPA), distance from another vessel, relative bearing, and velocity ratio are used as evaluation factors for ship collision risk. The basic probability assignments (BPAs) calculated by membership functions for each evaluation factor are fused through the combination rule of the Dempster-Shafer theory. As a result of the experiment using automatic identification system (AIS) data collected in situations where ships actually encounter each other, the suitability of evaluation was verified. By evaluating the risk of collision in real time in encounter situations between ships, collision accidents caused by human errora can be prevented. This is expected to be used for vessel traffic service systems and collision avoidance systems for autonomous ships.