SDH 기반의 동기식 광전송망 설계 체계에 관한 연구

고속/광대역 통신을 위하여 동기식 디지털 전송계위(Synchronous Digital Hieraachy: SDH)에 따른 전송망의 구축이 필수적으로 요구되고 있다. 특히, 광통신 기술을 이용한 동기식 광존송망의 구축이 활발히 진행되고 있는데, 이에 대한 시설투자에 막대한 비용이 소요되므로 경제적인 광전송망을 구축하기 위한 체계적인 전송망 구축계획이 수립되어야 한다. 경제적인 광전송망을 구축하기위해서는 효과적인 설계도구가 필요하다. 본 연구에서는 이같은 설계도구의 개발을 위한 체계적인 설계절차를 소개함으로써, 동기식 광전송망 설계 및 구축시에 유용하게 활용하도록 한다. 따라서 본 연구에서는 광전송망 설계를 위한 전반적인 접근방법과, 특정한 부문제의 고려시에 검토될 수 있는 모형의 소개에 연구의 초점을 두고자 한다. 본 연구에서 제시하는 전반적인 설계절차는 전체문제를 다수의 부문제로 분할하여 접근하는 방법이지만, 문제의 분할 수준과 설계모형은 수요의 특성, 장비의 특성 및 효과적인 해법의 개발 등을 고려하여 기존의 방법과는 다른 새로운 접근방식을 소개한다. 본 연구에서 제시하는 설계절차는 국내의 동기식 광전송망 설계도구를 개발하는 데 있어 하나의 방법론으로 활용될 수 있을 것이다

Scheduling Tasks for a Time Sharing Computer System with a Single Processor

This article is confirmed to be submitted through the review and edition of the Korean Operations Research and Management Science Society. Please enter the title (Journal/Proceedings), volume, number, and pages properly when citing the article.We consider a time sharing computer system with a single processor where tasks of K different types arrive at the system according to independent time homogeneous Poisson processes from outside. A task, after given a quantum for processing, leaves the system, or changes the type and rejoins the system according to specified probabilities. While many existing priority time sharing models determine the priorities of tasks strictly by their service time requirements, this paper develops a new scheduling rule wherein the importances or urgencies in addition to the service time requirements of tasks are counted, by imposing an appropriate reward structure on the system. Also presented is the algorithm thruough which to determine the rankings of K types according to this new scheduling rule.

Opportunistic Replacement Policies under Markovian Deterioration

Consider a series system of two units, named 1 and 2, respectively. Two units are observed at the beginning of discrete time periods t=0,1,2, ⋯ and classified as being in one of a countable number of states. Let (i, r) be a state of the system at time t, when the state of unit 1 is i and state of unit 2 is r at time t, Under some conditions, the opportunistic replacement policy that minimizes the expected total discounted cost or the average cost of maintenance is shown to be characterized by the control limits i⋅(r) (a function of r) and r⋅(i) (a function of i) : (a) in observed state (i, r), the optimal policy for unit 1 is to replace if i{≥}i⋅(r) and no action otherwise; (b) in observed state (i, r), the optimal policy for unit 2 is to replace if r{≥}r⋅(i) and no action otherwise. In addition, this paper also develops optimal policy in the finite time horizon case, where time horizon is fixed or a finite integer valued r.v. with known pmf

Power-Efficient Cell Coverage Control in a CDMA System

In cellular wireless system, transmitted power is regulated to provide each user an acceptable connection while limiting the interference from other users. In this work, we integrate power budgeting and base station assignment. In the context of CDMA system, we minimize the total transmitted power subject to maintaining an individual target CIR for each mobile and base station. We formulate the optimization model and a solution method is proposed

Routing in Computer Networks: A Survey of Algorithms

The purpose of this parer is to provide a survey of the state of the art of routing methods in store-and-forward computer networks. The survey is carried out in line with a new taxonomy： heuristic methods, user-optimization methods, and system-optimization methods. This taxonomy on routing algorithms is based on two viewpoints： the level of optimization and the relative difficulty for the implementation in real computer networks. Some actual methods implemented in real computer networks are surveyed as well as the theoretical studies in the literature. This paper concludes with some points in need of further researches

불확실한 수요와 기술환경을 고려한 가입자망 진화 의사결정모형

The environment of the access network service market is characterized by uncertain demand and various competing alternative technologies. In Korea, despite the introduction of competition, dominant Public Network Operater(PNO) still leads the market. Therefore, the decision of PNO has a great impact on the access network evolution. In this paper, we propose an model which aims to reduce risks and both investment and operating costs, to cope with the uncertain demand and provide a tool to analyze risks and evaluate various strategies on the access network evolution