• Journal of Korean Society of Industrial and Systems Engineering
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• v.21 no.48
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• pp.113-122
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• 1998

In this paper we consider the CSP requirements determination problem of new equipment(machine) system. For the newly procured equipment systems, mathematical analyses are made for the system which is constructed with the consumable parts to derive the associated CSP requirement determination model in mathematical expression. Based on these analyses, a mathematical model is derived for making an optimal CSP requirement determination subject to tile constraint of satisfying any given operational availability limitation. We assume that the failure of a part follows a Poisson process. Firstly, the operational availability concept in CSP is defined and the relation between the general system availability and the operational availability is established. Secondly, the problem is formulated as the cost minimization problem that should satisfy the operational availability limitation, and then, using the generalized Lagrange multipliers method, the optimal solution procedure is derived.

• Journal of the Korea Society for Simulation
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• v.10 no.3
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• pp.83-94
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• 2001

In this paper, the consumable spare parts requirement determination problem of newly procured equipment systems is considered. The problem is formulated as the cost minimization problem with operational availability constraint. Assuming part failure rate is constant during operational period, an analytical method is developed to obtain spare part requirements. Since this solution tends to overestimate the requirements, a fast search simulation procedure is introduced to adjust it to the realistic solution. The analytical solution procedure and the simulation procedure are performed recursively until a near optimal solution is achieved. The experimental results show that the near optimal solution is approached in a fairly short amount of time.

• ETRI Journal
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• v.45 no.1
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• pp.150-162
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• 2023

The polar delta-sigma modulator (DSM) transmitter architecture exhibits good coding efficiency and can be used for software-defined radio applications. However, the necessity of high clock speed is one of the major drawbacks of using this transmitter architecture. This study proposes a low-complexity timeinterleaved architecture for the polar DSM transmitter baseband part to reduce the clock speed requirement of the polar DSM transmitter using an upsampling technique. Simulations show that using the proposed four-branch timeinterleaved polar DSM transmitter baseband part, the clock speed requirement of the transmitter is reduced by four times without degrading the signal-tonoise-and-distortion ratio.

• The KIPS Transactions:PartD
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• v.17D no.4
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• pp.271-282
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• 2010

Insufficient requirement management accounts for 54% ofunsuccessful software development projects and 22% of insufficient requirement management comes from requirement change management. Hence, requirement management activities are important to reduce failure rates and a tracing method is suggested as the major factor in requirements change management. A traceability table is easy to use because of its legibility accurate tracing. However, traceability tables of existing studies have failed to concretely suggest method of change management and effect of traceability. Also, studies of methods to estimate change impact is complex. Hence, this study suggests how to use a traceability table to manage changes in requirements. Together, in comparison to existing studies, this study suggests easier methods to estimate change rate and change impact. Also Fifteen projects were sampled to test the hypothesis that traceability table influences the success of projects and that it decreases the failure rate that comes from the insufficient requirements management.

• Design & Manufacturing
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• v.10 no.3
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• pp.1-7
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• 2016

In the semiconductor industry the memory and chip were developed to high density memory and high performance chip, so circuit design was also high integrated and the test bed was needed to be thin and fine pitch socket. LGA(Land Grid Array) IC socket with thin wall thickness was designed to satisfy this requirement. The LGA IC socket plastic part was manufacture by injection molding process, it was needed accuracy, stiffness and suit resin with high flowability. After injection molding process the side gates were needed to remove for further assembly process. ln this study, the cold press cutting process was applied to remove the gates. For design of punch and die, the cold press cutting analysis was implemented by$DEFORM-2D^{TM}$ ln consideration of the simulation results, an adequate punch and die was designed and made for the cutting unit. In order to verify the performance of cutting process, the roughness of cutting section of the part was measured and was satisfied in requirement.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2014.05a
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• pp.10-11
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• 2014

Energy load of building affected by insulation performance of building's exterior. and insulation system can be classify interior insulation, exterior insulation, sandwich insulation according to install place of insulation. but within interior insulation system, corner wall and the cross outer wall-slab insulation part may occur thermal bridges. And then, within exterior insulation system is more superior insulation performance than interior insulation, but it has difficult to apply, easily broken at high building because of strong wind load. And also difficult to maintenance exterior insulation system. So, in this study, to found requirement performance of cast-in-place sandwich insulation system that is superior insulation performance and easy construction and maintenance. requirement performance of cast-in-place sandwich insulation system is 1) To avoid thermal bridges in the insulation performance, 2) Both sides concrete wall can be composite action in the structural performance. Because of this study, can develops cast-in-place sandwich insulation system and this insulation system contribute to improve insulation performance of apartment-house and high building.

• Journal of Satellite, Information and Communications
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• v.2 no.1
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• pp.41-47
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• 2007

Software GNSS digitized IF signal simulator is being developed by ETRI as a part of development of software-based GNSS Test & evaluation Facility which will provide test and evaluation environment for various software level application and navigation algorithm in GNSS. Software GNSS IF signal simulator will provide digitized GNSS signal including GPS and Galileo. The requirement analysis and conceptual design for the Software GNSS IF signal simulator is presented in this paper.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1179-1180
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• 2007

Urban transit is system that offer target Performance and function because various lower part system such as vehicles, signaling, power supply, rail track is consisted as complex. It is important first of all that describe correctly system requirement until configuration of system, design, manufacture, installation and test verification so that the complicated urban transit system is to act safety and reliable and to display target Performance and function properly. The system requirement assist the system developer to comprehensive the performance and function of system in basic design. Therefore, In this paper wishes to study way to analyze system of system requirement and apply to Urban transit.

• Journal of Applied Reliability
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• v.4 no.2
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• pp.91-104
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• 2004

In this paper we consider the concurrent spare part(CSP) requirements problem of new equipment system. When a part fails, the part is replaced and the repair of failed part is impossible and cannibalization is allowed. We assume that the failure of a part knows a Poisson process. The operational availability concept in CSP is defined, and derive a formula to calculate the operational availability using expected machine operating time during CSP period. A mathematical model is derived for making an CSP requirement determination subject to the constraint of satisfying any given operational availability limitation and an heuristic solution search procedure is derived. An illustrative example is shown to explain the solution procedure.

• Journal of the Korea Institute of Military Science and Technology
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• v.13 no.5
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• pp.801-807
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• 2010

Requirements management is one of the most essential activities of systems engineering in developing successful weapon systems. Particularly it is very important to consistently manage the traceability among the user requirements, the system requirements, the development specifications and the testing plans throughout the entire life cycle of the weapon system. However, the most part of requirements-related activities has centered around the functional and performance requirements but the integrated logistics support(ILS) requirement has not properly been managed. In this regard, a special attention is needed to develop and manage the ILS requirements. To do so, the ANSI/EIA-632 standard can be referred as a starting point since the ILS requirements of the weapon system under development are specified by the enabling products whereas the functional and performance requirements are covered by the end product requirements. Specifically, we first review and model several cases of previous weapon systems development, which reveals the problem of interest. Then, under the framework of ANSI/EIA-632, we study a hierarchical model for effectively managing ILS requirements by analyzing the features of ILS requirements. Finally, the value of the proposed model is discussed through the case study of electronic warfare equipment.