• 경영과정보연구
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• 제5권
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• pp.287-300
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• 2000

Project Managers want to reduce the cost and the completion time of the project simultaneously. But the project completion time tends to increase as the project cost is reduced, and the project cost has a tendency to increase as the project completion time is reduced. In this paper, the resource constrained project scheduling problem with multiple crashable modes is considered. An exact solution method for finding the efficient solution set and the computational results are introduced.

• IEIE Transactions on Smart Processing and Computing
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• 제1권2호
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• pp.95-105
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• 2012

The widespread implementation of RFID in ubiquitous computing is constrained considerably by privacy and security unreliability of the wireless communication channel. This failure to satisfy the basic, security needs of the technology has a direct impact of the limited computational capability of the tags, which are essential for the implementation of RFID. Because the universal application of RFID means the use of low cost tags, their security is limited to lightweight cryptographic primitives. Therefore, EPCGen2, which is a class of low cost tags, has the enabling properties to support their communication protocols. This means that satisfying the security needs of EPCGen2 could ensure low cost security because EPCGen2 is a class of low cost, passive tags. In that way, a solution to the hindrance of low cost tags lies in the security of EPCGen2. To this effect, many lightweight authentication protocols have been proposed to improve the privacy and security of communication protocols suitable for low cost tags. Although many EPCgen2 compliant protocols have been proposed to ensure the security of low cost tags, the optimum security has not been guaranteed because many protocols are prone to well-known attacks or fall short of acceptable computational load. This paper proposes a remedy protocol to the flyweight RFID authentication protocol proposed by Burmester and Munilla against a desynchronization attack. Based on shared pseudorandom number generator, this protocol provides mutual authentication, anonymity, session unlinkability and forward security in addition to security against a desynchronization attack. The desirable features of this protocol are efficiency and security.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2004년도 가을 학술발표회 논문집
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• pp.150-156
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• 2004

Though the concept of Life-Cycle Cost (LCC) itself is not new, its effectiveness for planning, design, rehabilitation and maintenance/management of civil infrastructures is becoming increasingly recognized. For the decision problems as in the case of the LCC of plant facilities, equipments, bridge decks, pavements, etc., the Life-Cycle Cost Analysis (LCCA) is relatively simple, and thus its practical implementation is rather straightforward. However, when it comes to major infrastructures such as bridge, tunnels, underground facilities, etc., the LCCA problem becomes extremely complex because lack of cost data associated with various direct and indirect losses, and the absence of uncertainty data available for the assessment as well. As a result, the LCC studies have been largely limited only to those relatively simple LCCA problems of planning or conceptual design for making decisions. Accordingly, in the recent years, the researchers have pursued extensive studies on the LCC effectiveness mostly related to LCC models and frameworks for civil infrastructures. Moreover, recently the demand on the practical application of LCC effective decisions in design and maintenance is rapidly growing unprecedently in civil engineering practice. Indirction cost is very important on LCC formulation. But that is very difficult and complicate the estimation every LCC. The objective of this paper is to suggest efficient regression model for the estimation of indirect cost approach to the practical application of LCC for the design and rehabilitation of civil. infrastructures considering traffic, traffic network, detour condition, and workzone condition. In this paper, it performed the sensitivity analysis and correlation analysis of parameter for development of regression model of inflection cost.

• 한국통신학회논문지
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• 제36권1C호
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• pp.14-21
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• 2011

겹선형 페어링(bilinear pairing)을 기반으로 하는 암호 프로토콜들은 이산 대수 문제를 기반으로 하는 전통적인 타원 곡선 암호시스템을 대신하여 여러 방면에의 응용성을 제공한다. 겹선형 페어링의 빠른 계산을 위하여 최근 활발한 연구가 진행 중이지만, 여전히 ECC 상수배 연산에 비해서 페어링 연산에 사용되는 계산 비용은 상당히 크다고 여겨진다. 그러나 이진 유한체상의 페어링 계산 연구는 최근 많은 발전이 이루어졌다. 본 논문에서는 이진 유한체상에서의 BLS 서명스킴과 ECDSA 서명 스킴의 복잡도를 비교한다. 공정한 비교를 위하여 1024-bit RSA와 같은 레벨의 보안성을 가지는 160-bit ECDSA와 250-bit BLS를 선택하였다. 분석결과 BLS 스킴은 ECDSA에 비해 하드웨어 복잡도 및 계산 지연시간의 측면에서 많은 차이가 나지 않음을 설명해준다.

• 한국전산구조공학회논문집
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• 제18권4호통권70호
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• pp.445-452
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• 2005

본 논문에서는 강박스 거더의 생애주기비용을 최소화하기 위한 방법을 제시하였다. 본 논문에서 고려된 강박스 거더의 생애주기비용은 초기비용, 유지관리비용 및 보수비용으로 구성되었다. 강재 주형의 상태등급곡선과 안전진단 결과 측정된 내하력을 바탕으로 내하력곡선을 추정하였으며, 이 곡선을 이용하여 생애주비용을 고려한 강박스 거더의 최적설계를 수행하였다. 또한 내하력곡선을 통해 강박스 거더의 공용수명과 보수 보강 시기 및 횟수를 결정하고 초기 내하력에 따른 생애주기 동안 발생하는 연간비용을 비교, 분석하였다. 본 논문에서 제안한 생애주기비용을 고려한 강박스 거더의 최적설계를 통하여 기존의 설계에 비해 보다 경제적이며 안전한 설계를 유도할 수 있으리라 판단된다.

• 한국전산구조공학회논문집
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• 제29권5호
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• pp.429-436
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• 2016

연구에서는 철근콘크리트 건물에 대한 유전자 알고리즘 기반의 최적구조설계기법을 제시하고자 한다. 목적함수는 구조물의 비용과 이산화탄소 배출량을 동시에 각각 최소화하는 것이다. 비용 및 인산화탄소 배출량은 구조설계안에서 얻을 수 있는 단면치수, 부재길이, 재료강도, 철근량 등과 같은 설계정보를 통해 계산한다. 즉, 구조물의 물량을 기초로 하여 비용과 이산화탄소 배출량을 평가한다. 재료의 운반, 시공 및 건물 운영 단계에서 발생하는 비용 및 이산화탄소 배출량은 본 연구에서 제외한다. 제약조건은 철근콘크리트 건물을 구성하는 기둥과 보 부재의 강도조건과 층간변위조건이 고려된다. 제약조건을 평가하기 위해 OpenSees를 활용한 선형정적해석이 수행된다. 제약조건을 만족시키면서 목적함수에 대해 최소의 값을 제시하는 설계안을 찾기 위해 유전자 알고리즘이 사용된다. 제시한 알고리즘의 적용성을 검증하기 위해 4층 철근콘크리트 모멘트 골조 예제에 제시하는 기법을 적용하여 검증한다.

• 한국경영과학회:학술대회논문집
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• 한국경영과학회 2006년도 추계학술대회
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• pp.332-335
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• 2006

This paper considers a facility location problem, which is concerned with locating facilities on a supply chain network and installing the associated equipments at the facilities to meet a given set of demands. The objective function is to minimize the sum of setup cost (facility opening cost and equipment installation cost), operation cost, and distribution cost. For the equipments, various choices of equipment modes need to be determined. Moreover, in the problem, overwork is allowed each facility but at expensive operation cost. The proposed problem is characterized as being NP-hard problem, so that a heuristic algorithm is derived. In order to evaluate the performance of the proposed algorithm, computational experiments with various numerical instances are conducted.

• Journal of applied mathematics & informatics
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• 제9권1호
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• pp.61-76
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• 2002

The robust non-fragile guaranteed cost control problem is studied in this paper for class of uncertain linear large-scale systems with time-varying delays in subsystem interconnections and given quadratic cost functions. The uncertainty in the system is assumed to be norm-hounded arid time-varying. Also, the state-feedback gains for subsystems of the large-scale system are assumed to have norm-bounded controller gain variations. The problem is to design state feedback control laws such that the closed-loop system is asymptotically stable and the closed-loop cost function value is not more than a specified upper bound far all admissible uncertainties. Sufficient conditions for the existence of such controllers are derived based on the linear matrix inequality (LMI) approach combined with the Lyapunov method. A parameterized characterization of the robust non-fragile guaranteed cost contrellers is 7iven in terms of the feasible solution to a certain LMI. Finally, in order to show the application of the proposed method, a numerical example is included.

• Journal of applied mathematics & informatics
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• 제39권5_6호
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• pp.895-918
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• 2021

Human African Trypanosomiasis (HAT) also known as sleeping sickness, is a neglected tropical vector borne disease caused by trypanosome protozoa transmitted by bites of infected tsetse fly. The basic reproduction number, R₀ derived using the next generation matrix method which shows that the disease persists in the population if the value of R₀ > 1. The numerical simulations of optimal control model carried out to determine the control strategy that can combat HAT under the minimum cost. The results indicate that, the use of both education campaign, treatment and insecticides are more efficient and effective to eliminate HAT in African community but too costly. Furthermore, the cost-effectiveness of the control measures (education campaign, treatment and insecticides) were determined using incremental cost-effectiveness ratio (ICER) approach and the results show that, the use of education and treatment of infected people as the best cost effective strategy compared to other strategies.

• Earthquakes and Structures
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• 제14권5호
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• pp.437-447
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• 2018

Computational cost is one of the major obstacles for detailed risk analysis of structures. This paper puts forward a methodology for efficient probabilistic seismic loss assessment of structures using the Endurance Time (ET) analysis and the first-order reliability method (FORM). The ET analysis efficiently yields the structural responses for a continuous range of intensities through a single response-history analysis. Taking advantage of this property of ET, FORM is employed to estimate the annual rate of exceedance for the loss components. The proposed approach is an amalgamation of two analysis approaches, ET and FORM, that significantly lower the computational costs. This makes it possible to evaluate the seismic risk of complex systems. The probability distribution of losses due to the structural and non-structural damage as well as injuries and fatalities of a prototype structure are estimated using the proposed methodology. This methodology is an alternative to the prevalent risk analysis framework of the total probability theorem. Hence, the risk estimates of the proposed approach are compared with those from the total probability theorem as a benchmark. The results indicate a satisfactory agreement between the two methods while a significantly lower computational demand for the proposed approach.