S O L V I N G A S E T C O V E R I N G P R O B L E M I N T H E U N C E R T A I N T Y C O N D I T I O N O F A N E M E R G E N C Y S Y S T E M W I T H A N O N-S T A T I O N A R Y Q U E U I N G A P P R O A C H U S I N G T W O M E T A-H E U R I S TICS
Author(s):
Abstract:
Set covering problems have attracted a great deal of attention by researchers in recent years, especially in emergency systems. One of the most important objectives in set covering problems is for emergency vehicles to be on time at accident locations in order to provide services. Based on real observations, service facilities (i.e., emergency vehicles) are not always available, and are provided in an uncertainty condition. Regarding these problems, after defining customer location, facility centers are selected from candidate points to present services to customers efficiently. Hence, an appropriate method is investigated to localize emergency centers, so that accident locations receive appropriate services. In this paper, a new approach, based on queuing systems, is presented for developing set covering problems, in which the arrival rate of the emergency services and service rate vary at different time intervals, as shown by $lambda(t)$ and $mu(t)$, respectively. These are categorized as non-stationary queuing systems with time-varying rates, which is a probability variable, depending on the traffic conditions, accidents, weather conditions, failure of vehicles, and condition of routes, and so on. To approximate arrival and service rates innon-stationary M(t) /M(t) /1 queuing systems, their average rates can be considered to determine the probability of available facilities. Since exact solutions of the set covering problems that belong to the category of NP-hard problems are not practical on a large scale, two meta-heuristic algorithms, namely; Improved Particle Swarm Optimization (IPSO) and Simulated Annealing (SA), are presented, and the results are compared with the branch and bound algorithm in small size problems. At the end, a number of test problems in large scale are solved, and the efficiency of the foregoing algorithms is evaluated. The results have shown that IPSO obtained high quality solutions with a reasonable computational time and accuracy, rather than the SA algorithm.
Keywords:
Language:
Persian
Published:
Industrial Engineering & Management Sharif, Volume:29 Issue: 1, 2013
Pages:
33 to 42
magiran.com/p1203240
دانلود و مطالعه متن این مقاله با یکی از روشهای زیر امکان پذیر است:
اشتراک شخصی
با عضویت و پرداخت آنلاین حق اشتراک یکساله به مبلغ 1,390,000ريال میتوانید 70 عنوان مطلب دانلود کنید!
اشتراک سازمانی
به کتابخانه دانشگاه یا محل کار خود پیشنهاد کنید تا اشتراک سازمانی این پایگاه را برای دسترسی نامحدود همه کاربران به متن مطالب تهیه نمایند!
توجه!
- حق عضویت دریافتی صرف حمایت از نشریات عضو و نگهداری، تکمیل و توسعه مگیران میشود.
- پرداخت حق اشتراک و دانلود مقالات اجازه بازنشر آن در سایر رسانههای چاپی و دیجیتال را به کاربر نمیدهد.
In order to view content subscription is required
Personal subscription
Subscribe magiran.com for 70 € euros via PayPal and download 70 articles during a year.
Organization subscription
Please contact us to subscribe your university or library for unlimited access!