• 한국시뮬레이션학회논문지
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• 제28권3호
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• pp.57-63
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• 2019

본 연구는 중소기업퇴직연금제도가 가입자들에게 보증이율(최소수익률)을 제공할 경우 사전에 적립해야 하는 보증준비금 수준을 산출하여 제시하였다. 보증준비금을 산출하기 위한 방법론으로 본 연구는 변액연금보험의 보증준비금 산출 방법론을 적용하였다. 보증준비금 산출을 위해 2010년부터 2018년까지의 3대 연기금의 자산운용 평균 수익률을 기금형 제도의 목표수익률로 설정하였으며, 보증이율은 0%, 1.0%, 1.5%, 2.0%를 각각 적용하여 시나리오 별로 요구되는 보증준비금을 산출하였다. 주요 결과로 첫째, 제도 도입기간이 길어질수록 초기 설정한 보증이율에 따른 보증준비금 간의 차이는 증가하는 것으로 나타났다. 둘째, 제도가 성숙함에 따라 적립금이 부족할 가능성은 체감하였다. 결론적으로 보증이율투자전략에 내제된 수익-위험의 관계는 장기적으로 보수적 균형을 이루어야 함을 의미한다.

• 전기학회논문지
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• 제56권11호
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• pp.1892-1902
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• 2007

This paper presents a new generating unit maintenance scheduling algorithm considering regional reserve margin and transfer capability. Existing researches focused on reliability of the overall power systems have some problems that adequate reliability criteria cannot be guaranteed in supply shortage regions. Therefore specific constraints which can treat regional reserve ratio have to be added to conventional approaches. The objective function considered in this paper is the variance (second-order momentum) of operating reserve margin to levelize reliability during a planning horizon. This paper focuses on significances of considering regional reliability criteria and an advanced hybrid optimization method based on PSO algorithm. The proposed method has been applied to IEEE reliability test system(1996) with 32-generators and a real-world large scale power system with 291 generators. The results are compared with those of the classical central maintenance scheduling approaches and conventional PSO algorithm to verify the effectiveness of the algorithm proposed in this paper.

• Journal of the Korean Data and Information Science Society
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• 제24권4호
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• pp.723-736
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• 2013

해약율의 추정은 최근 보험제도의 변화 (국제회계기준의 도입에 따른 현금흐름방식의 가격산출체계 시행, 무해약환급금 보험상품의 판매 허용 등)에 따라 보험료의 결정과 손익분석 그리고 리스크 관리 등에 있어서 중요한 요소로 부각되고 있다. 특히, 변액연금은 최저보증옵션으로 인하여 보험계약자의 해약요소가 중요시되고 다른 보험 상품에 비해 복잡하므로 차별성 있는 통계모형의 선택과 분석이 필요하다. 기존의 해약률 연구는 실태분석 또는 회귀분석을 위주로 모형화하는 것에 초점이 맞추어져 있었으나 본 연구에서는 변액연금 계약과 관련된 여러 변수와 최저보증옵션을 반영하기 위하여 생존분석기법 중 하나인 Cox 비례위험모형을 이용하여 해지율을 추정하였다. 변액연금 해지율에 영향을 미치는 주요변수로는 납입방법, 보험료, 보험기간 대비 유지기간, 계약자적립금 대비 최소보증금, 계약자연령이 있으며 본 연구에서는 이에 관하여 분석해보았다.

• 한국통신학회논문지
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• 제36권4A호
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• pp.380-387
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• 2011

While mobile IPTV services are supported through the mobile WiMAX networks, there must need some guaranteed bandwidth for the IPTV services especially if IPTV and non-IPTV services are simultaneously supported by the mobile WiMAX networks. The quality of an IPTV service definitely depends on the allocated bandwidth for that channel. However, due to the high quality IPTV services and to support of huge non-IPTV traffic over mobile WiMAX networks, it is not possible to guarantee the sufficient amount of the limited mobile WiMAX bandwidth for the mobile IPTV services every time. A Service Level Agreement (SLA) between the mobile IPTV service provider and mobile WiMAX network operator to reserve sufficient bandwidth for the IPTV calls can increase the satisfaction level of the mobile IPTV users. In this paper, we propose a SLA negotiation procedure for mobile IPTV users over mobile WiMAX networks. The Bandwidth Broker controls the allocated bandwidth for IPTV and non-IPTV users. The proposed dynamically reserved bandwidth for the IPTV services increases the IPTV user's satisfaction level. The simulation results state that, our proposed scheme is able to provide better user satisfaction level for the IPTV users.

• Journal of Communications and Networks
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• 제12권2호
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• pp.114-121
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• 2010

In this paper, an auctioning strategy is proposed for cellular networks that ensures net energy savings. The pricing scheme, in conjunction with a two dimensional bid structure, incentivizes cooperation at the terminal nodes for better interference management at receivers and for cooperative relaying. It is shown that, for the proposed auctioning strategy, network operators are guaranteed revenue gains, mobile nodes' dominant strategy is to bid their true valuation of their energy resources, and overall effective energy gains occur under the assumption of a reserve price for bidding. Simulation results show that significant energy savings can be achieved by employing this auctioning mechanism for a 3G cellular set-up.

• 한국정보과학회논문지:정보통신
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• 제35권6호
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• pp.538-548
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• 2008

IETF(Internet Engineering Task Force) NSIS(Next Step in Signaling) 워킹그룹에서는 MN(Mobile Node)의 핸드오버로 인해 데이타 전달 경로가 변경된 경우, 이전 경로와 새로운 경로가 분기 또는 통합되는 지점에 있는 노드인 CRN(Crossover Node)을 발견하는 방안을 제안하였다. 이 방안에서는 CRN 발견을 통해 새로운 경로 상에 자원예약 시그널링 지연을 줄이고 이전 경로와 새로운 경로의 공통경로 상에 중복 자원예약을 피함으로써 핸드오버 이후의 자원예약을 효율적으로 수행한다. 그러나 MN이 핸드오버하는 동안 지속적으로 QoS(Quality of Service)를 보장받기 위해서는 핸드오버 이전에 새로운 경로 상의 사전자원예약이 이루어져야 한다. 그런데 아직 핸드오버하지 않은 MN이 새로운 경로 상에 사전자원예약을 수행하려는 경우에는 기존의 CRN 메커니즘을 적용하기 어렵다. 이에 본 논문에서는 현재 자인이 예약된 경로와 MN이 핸드오버 할 가능성이 있는 하나 이상의 지역의 새로운 경로 상에 CRN이 될 가능성이 있는 노드인 PCRN(Passive Crossover Node)을 발견하고, 이후 새로운 경로 상에 사전자원예약을 수행하는 방안을 제안한다.

• 정보처리학회논문지C
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• 제9C권2호
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• pp.297-306
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• 2002

멀티미디어 어플리케이션들은 기존의 화일 서버 기법으로는 쉽게 제공하지 못하는 보장된 검색 및 전송률을 요구한다. 본 논문에서는 CM(Continuous Media : 예를 들어 비디오) 서버를 위한 동적 협상 수락 제어(dynamic negotiated admission control)와 자원 스케줄링(resource scheduling) 기법을 제안한다. 이는 두 부분으로 구성되는데, 예약 기반 수락 제어 방법(reserve-baed admission control mechanism)과 동적으로 자원을 할당하는 스케줄러가 그것이다. 정적 스케줄러와 비교할 때, 제안된 기법은 경쟁하는 스트림들에게 이용가능 한 자원들을 효과적으로 공유할 수 있도록 해주며, 전반적인 QoS(Quality of Service)를 향상시키기 위해 자원의 재 할당을 요구하는 스트림들을 위한 스케줄러 초기화 협상(scheduler-initiated negotation)을 통해 높은 이용률을 얻을 수 있다. 본 논문에서 제안한 기법을 사용하여 동시에 실행시킬 수 있는 클라이언트의 수를 증가시킬 수 있으며 혼잡한 트래픽 상태에서도 좋은 응답 비율과 향상된 자원 이용률을 얻을 수 있다.

• 한국군사과학기술학회지
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• 제16권2호
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• pp.160-168
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• 2013

In tactical environment, tactical wireless networks are generally comprised of Tactical MANETs(T-MANETs) or Tactical WMNs(T-WMNs). The most important services in tactical network are voice and low rate data such as command control and situation awareness. These data should be forwarded via multi-hop in tactical wireless networks. Urgent and mission-critical data should be protected in this environment, so QoS(Quality of Service) must be guaranteed for specific type of traffic for satisfying the requirement of a user. In IEEE 802.11s, TDMA-based MAC protocol, MCCA(MCF Controlled Channel Access), has a function of resource reservation. But 802.11s protocol can not guarantee the end-to-end QoS, because it only supports reservation with neighbors. In this paper, we propose the routing protocol, R-HWMP(Reservation-based HWMP) which has the resource reservation to support the end-to-end QoS. The proposed protocol can reserve the channel slots and find optimal path in T-WMNs. We analyzed the performance of the proposed protocol and showed that end-to-end QoS is guaranteed using NS-2 simulation.

• 전기학회논문지
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• 제56권10호
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• pp.1731-1737
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• 2007

The Korea electricity wholesale market is operated under the cost-based-pool system and the government regulation to the new generation capacities in order to insure the resource adequacy. The goal of government's regulation is the electricity market stability by attracting proper generation investment while keeping the reliability of system. Generation companies must mandatory observe that government plan by now. But if the restructuring is to be complete, generation companies should not bear any obligation to invest unless their profitability is guaranteed. Namely the investors' behavior will be affected by the market prices. In this paper, the system dynamics model for Korea wholesale electricity market to examine whether competitive market can help to stabilize is developed and analyzes the investors behavior. The simulation results show that market controlled by government will be operated stable without resulting in price spike but there is no lower price because of maintaining the reasonable reserve margin. However, if the competition is introduced and the new investment is determined by the investor's decision without government intervention, the benefits from lower wholesale price are expected. Nevertheless, the volatility in the wholesale market increases, which increases the investment risks.

• 기술사
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• 제34권4호
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• pp.41-47
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• 2001

The paper describes SR3 (Synchronous Round Robin with Reservations), a collision-free medium access control protocol for all-optical slotted packet networks based on WDM multi-channel ring topologies where nodes are equipped with one fixed-wavelength receiver and one wavelength-tunable transmitter SR3 is derived from the SRR and MMR protocols previously proposed by the same authors for the same class of all-optical networks. SRR and MMR already achieve an efficient exploitation of the available bandwidth, while guaranteeing a throughput-fair access to each node. SR3, In addition, allows nodes to reserve slots. thereby achieving a stronger control on access delays; it is thus well suited to meet tight delay requirements, as it is the case for multimedia applications. Simulation results show that SR3 provides very good performance to guaranteed qualify traffic, but also brings signigicant performance improvements for best-effort traffic. Energy effciency is an important issue for optical network since they must rely on their batteries. We present a novel MAC protocol that achieves a good energy efficiency of optical interface of the network and provides support for diverse traffic types and QoS. The scheduler of the base station is responsible to provide the required QoS to connections on the optical link and to minimise the amount of energy spend by the High speed Network. The main principles of the MaC protocol are to avoid unsuccessful actions, minimise the number of transitions , and synchronise the mobile and the base-station. We will show that considerable amounts of energy can be saved using these principles.