• Proceedings of the KIEE Conference
• /
• 2008.07a
• /
• pp.46-47
• /
• 2008

전력산업은 국가경제 및 국민생활의 기반이 되는 기간산업으로서 그 역할이 중대하므로 계통운영자는 적정 예비력을 확보하여 양질의 전기를 안정적이고 효율적으로 공급해야 한다. 그러나, 계통규모의 지속적인 증가와 전력수급의 지역적 편중 가속화로 국내 여건은 갈수록 악화되고 있는 실정이다. 또한, 현행 예비력 기준은 계통규모와는 상관없이 정량적으로 확보하게 되어 있으며 예비력 소진시 재 확보해야 할 기준도 마련되어 있지 않다. 따라서, 본 논문에서는 지역적 계통특성을 반영하고 항목별 예비력 기준을 세분화하여 보다 체계적인 예비력 운영기준을 제시하고자 한다.

• Journal of applied mathematics & informatics
• /
• v.27 no.5_6
• /
• pp.1033-1047
• /
• 2009

In this paper, we consider a m-type risk model with Markov-modulated premium rate. A integral equation for the conditional ruin probability is obtained. A recursive inequality for the ruin probability with the stationary initial distribution and the upper bound for the ruin probability with no initial reserve are given. A system of Laplace transforms of non-ruin probabilities, given the initial environment state, is established from a system of integro-differential equations. In the two-state model, explicit formulas for non-ruin probabilities are obtained when the initial reserve is zero or when both claim size distributions belong to the $K_n$-family, n $\in$ $N^+$ One example is given with claim sizes that have exponential distributions.

• The Transactions of the Korean Institute of Electrical Engineers A
• /
• v.51 no.6
• /
• pp.269-275
• /
• 2002

Recently, Korea's electric industry has experienced substantial changes in its structure and function including the introduction of competition in the generation sector. Korea is in the early stages of market competition where the market price is determined by generation costs. In the future, the market Price will be determined by generators'bids. Therefore, the generators'profit is determined by market pool price, the prospects of pool price are very important for new capacity investment decision made by generators and IPPS. This study analyzes hourly marginal costs and LOLP considering basic generation mix and characteristics develops the relationship of pool price and Profit by generation-type using the change in reserve margin, and proposes basic direction for profits variation and supply-demand analysis in the electricity market in future.

• The Korean Journal of Nuclear Medicine
• /
• v.39 no.2
• /
• pp.133-140
• /
• 2005

The potential for recovery of left ventricular dysfunction after myocardial revascularization represents a practical clinical definition for myocardial viability. The evaluation of viable myocardium in patients with severe global left ventricular dysfunction due to coronary artery disease and with regional dysfunction after acute myocardial infarction is an important issue whether left ventricular dysfunction may be reversible or irreversible after therapy. If the dysfunction is due to stunning or hibernation, functional improvement is observed. but stunned myocardium may recover of dysfunction with no revascularization. Hibernation is chronic process due to chronic reduction in the resting myocardial blood flow. There are two types of myocardial hibernation: "functional hibernation" with preserved contractile reserve and "structural hibernation" without contractile reserve in segments with preserved glucose metabolism. This review focus on the application of F-18 FDG and other radionuclides to evaluate myocardial viability. In addition the factors influencing predictive value of FDG imaging for evaluating viability and the different criteria for viability are also reviewed.

• Proceedings of the KIEE Conference
• /
• 1997.07c
• /
• pp.1112-1114
• /
• 1997

When reliability is estimated to be insufficient, a planner must take action to improve them. So, the measures for improving reliability are mainly considered in the planning process. In order to provide quantitative information concerning reliability evaluation, this paper-describes an algorithm to find reserve margin in power system planning. The IEEE Reliability Test System(RTS) is used to demonstrate the effectiveness of the proposed algorithm.

• Journal of the military operations research society of Korea
• /
• v.14 no.1
• /
• pp.63-83
• /
• 1988

This study is concerned with the equilibrium bidding strategy and the optimal auction design of sequential auction with a reserve price and an entry fee. It is assumed that each bidder has a fixed reservation value and draws the reservation values of other bidders independently in the same distribution and may obtain at most one object to be sold. Under such assumptions, the sequential auction will be analyzed by the game theoretic approach. The purpose of this paper is, in the sequential auction, to find the equilibrium bidding strategy and to design the optimal auction under the equilibrium bidding strategy. The equilibrium bidding strategy and the optimal auction design are further analyzed with respect to change of the reserve price, the entry fee, and the number of bidders and objects. Specially, the auctioneer's expected revenue for each auction is obtained and analyzed.

• Proceedings of the KIEE Conference
• /
• 1995.07b
• /
• pp.540-542
• /
• 1995

When precontract pricing is applied, consumers must reserve expecting the amount of electricity to use. But Consumers expecting demand has stochastic property, expecting demand may be different from real demand. To prepare for this problem, spinning reserve is needed. Now I suggest new pricing system that someone has large variance and large elacity pays high price by the accumulated penalty factor. And I suggest the accumulated penalty factor for maximizing social welfare.

• Proceedings of the KIEE Conference
• /
• 2003.07a
• /
• pp.19-23
• /
• 2003

This paper presents a new concept of reactive reserve based contingency constrained optimal power flow (RCCOPF) for voltage stability enhancement. This concept is based on the fact that increase in reactive reserves is effective for enhancement of voltage stability margins of post-contingent states, in this paper, the proposed algorithm is applied to voltage stability margin of interface flow. Interface flow limit, in the open access environment, can be a main drawback. RCCOPF for enhancement of interface flow margin is composed of two modules, modified continuation power flow (MCPF) and optimal power flow (OPF). These modules art recursively perform ed until satisfying the required margin of interface flow in the given voltage stability criteria.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.28 no.1
• /
• pp.129-133
• /
• 2005

Slotted ALOHA(S-ALOHA) is widely used in local wireless network. We analyze the performance of contention-based model in wireless LAN using S-ALOHA protocol. We analyze the performance of binary exponential backoff (BEB) algorithm under the slotted ALOHA protocol: whenever a node's message which tries to reserve a channel is involved in a collision for the ith time, it chooses one of the next $2^i$ frames with equal probability and attempts the reservation again. We derive the expected access delay and throughput which is defined as the expected number of messages that reserve a channel in a frame. A simulation study is performed to verify our method.

• Journal of the military operations research society of Korea
• /
• v.13 no.2
• /
• pp.63-83
• /
• 1987

This study is concerned with the equilibrium bidding strategy and the optimal auction design of sequential auction with a reserve price and an entry fee. It is assumed that each bidder has a fixed reservation value and draws the reservation values of other bidders independently in the same distribution and may obtain at most one object to be sold. Under such assumptions, the sequential auction will be analyzed by the game theoretic approach. The purpose of this paper is, in the sequential auction, to find the equilibrium bidding strategy and to design the optimal auction under the equilibrium bidding strategy. The equilibrium bidding strategy and the optimal auction design are further analyzed with respect to change of the reserve price, the entry fee, and the number of bidders and objects. Specially, the auctioneer's expected revenue for each auction is obtained and analyzed.