• Management & Information Systems Review
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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.

• Proceedings of the Computational Structural Engineering Institute Conference
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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.

• The Journal of Korean Institute of Communications and Information Sciences
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• 제36권1C호
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• pp.14-21
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• 2011

Cryptographic protocols based on bilinear pairings provide excellent alternatives to conventional elliptic curve cryptosystems based on discrete logarithm problems. Through active research has been done toward fast computation of the bilinear pairings, it is still believed that the computational cost of one pairing computation is heavier than the cost of one ECC scalar multiplication. However, there have been many progresses in pairing computations over binary fields. In this paper, we compare the cost of BLS signature scheme with ECDSA with equvalent level of security parameters. Analysis shows that the cost of the pairing computation is quite comparable to the cost of ECC scalar multiplication for the case of binary fields.

• Journal of the Computational Structural Engineering Institute of Korea
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• 제18권4호통권70호
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• pp.445-452
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• 2005

This paper presents a design method to minimize Life Cycle Cost (LCC) of steel box girders. The LCC considered in this paper includes initial cost, expected life-cycle maintenance cost and repair cost. A load carrying capacity curve is derived from a condition grade curve of steel girders and load tarrying capacity that is measured in safety diagnostic test. And then, optimal design of steel box girders is performed on the basis of load carrying capacity curve. In this paper time and number of times for repair of steel girders are determined based on the calculated load carrying capacity curve. Also, annual costs considering real discount rate are compared and analyzed in various cases. It is concluded that the optimal design of steel box gilders considering LCC by the presented method will lead to more economical and safer girders than conventional design.

• Journal of the Computational Structural Engineering Institute of Korea
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• 제29권5호
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• pp.429-436
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• 2016

In this study, the genetic algorithm based optimal structural design method is proposed. The objective functions are to minimize the cost and $CO_2$ emissions, simultaneously. The cost and $CO_2$ emissions are calculated based on the cross-sectional dimensions, length, material strength, and reinforcement ratio of beam and column members. Thus, the cost and $CO_2$ emissions are evaluated by using the amounts of concrete and reinforcement used to construct a building. In this study, the cost and $CO_2$ emissions calculated at the phases of material transportation, construction, and building operation are excluded. The constraint conditions on the strength of beam and column members and the inter-story drift ratio are considered. The linear static analysis by using OpenSees is automatically conducted in the proposed method. The genetic algorithm is employed to solve the formulated problem. The proposed method is validated by applying it to the 4-story reinforced concrete moment frame example.

• Proceedings of the Korean Operations and Management Science Society Conference
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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.