• Journal of the military operations research society of Korea
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• v.32 no.1
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• pp.176-187
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• 2006

It is difficult to estimate missile flight trajectory since a ballistic missile velocity is highly fast and has inherent behavior such as corkscrew due to unstable descending. This paper describes a comprehensive analysis of the flight trajectory characteristics of ballistic missiles. Various missile flight ranges based the comprehensive flight trajectory characteristics are derived by an analytical approach. It is shown analytically that threat due to the flight characteristics is significantly increased with reducing maximum missile ranges. This work is basic research of the establishment of operational concept for the lower tier missile defense system implementation.

• Proceedings of the KIPE Conference
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• 2002.07a
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• pp.715-718
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• 2002

As the modern technology of continuous casting plant is focused on improvement of slab quality, the control system of strand driven roll which has positive effect is investigated in this paper. An irregular distribution of withdrawal force gives rise to horizontal crack in high and middle grade carbon steel. Based on the basic understanding on design concept of high technology company, monitoring the withdrawal force distribution of strand driven roll and analysis of the control system was Performed at continuous casters of POSCO. The control algorithm of withdrawal force distribution for A.C motor vector control, which was derived from above study and had been applied for POSCO Kwangyang 1-4 continuous casting plant, is presented.

• Proceedings of the KIPE Conference
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• 1998.10a
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• pp.366-373
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• 1998

In this paper, a new control strategy to reduce switching losses in three-phase voltage-source PWM converters is proposed according to Modified-Period-Average-Model (MPAN). The basic concept of this strategy is aimed at calculating the phase control voltages for controlling the source currents to be sinusoidal and in phase with the source voltages, and reducing the number of switching in each period. The phase control voltages of Period-Average-Model(PAM) is obtained according to analyzing the operation of PWM converter. In order to reduce the sensitivity to system parameters in PAM, MPAM is deduced. Then a square wave whose frequency is three times of utility frequency is added to the phase control voltages derived from MPAM. The control strategy reduces the switching losses since there exists about one-third blanking time for every phase in one period. The theoretical derivation and the control strategy are experimentally verified on a 2.5 kW three-phase voltage source converter.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11b
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• pp.69-72
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• 2001

A novel water-turbine, Katamax, for micro hydropower generator is proposed, which has reasonable efficiency even in two meters of water head. The basic concept of Katamax is similar to that of waterwheel except that Katamax has two axis on which the blades rotate, where general waterwheel has only one. Brief structure and principles of Katamax are explained and analysis for efficiency of each module are provided. The result of the prototype product of Katamax is briefly explained.

• Journal of Power Electronics
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• v.13 no.4
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• pp.729-736
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• 2013

Knowledge of a power semiconductor's operating temperature is important in circuit design and converter control. Designing appropriate circuitry that does not affect regular circuit operation during virtual junction temperature measurement at actual operating conditions is a demanding task for engineers. The proposed method enables virtual junction temperature estimation with a dedicated modified gate driver circuit based on real-time measurement of a semiconductor's quasi-threshold voltage. A simulation was conducted before the circuit was designed to verify the concept and to determine the basic properties and potential drawbacks of the proposed method.

• Archives of design research
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• v.21
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• pp.55-64
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• 1997

This paper is a study on the 'primitivism' which is constantly being applied on modem and contemporary textile design as a aItanative expression of the serious environmental phenomena of materialism. Starting with the analyzation of the 'concept of primitivism' , this paper is to research the 'origin of primitivism' which was first recognized by the modem artists. Primitivism on modem textile design will be suggested through 'trend terms'. The purpose of this paper is to be a basic material source for the creative development in design as well as to be of help in development of theoretical the study on contemporary textile design.

• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.3
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• pp.68-74
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• 2014

As the number of ECUs (Electronic control units) are increasing, reliability and functional stability of a software in an ECU is getting more important. Therefore the application of functional safety standards ISO 26262 is making the software more reliable. Software fault injection test (SFIT) is required as a verification technique for the application of ISO 26262. In case of applying SFIT, an artificial error is injected to inspect the vulnerability of the system which is not easily detected during normal operation. In this paper, the basic concept of SFIT will be examined and the application of SIFT based on ISO26262 will be described.

• Journal of the Korean Operations Research and Management Science Society
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• v.27 no.4
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• pp.11-27
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• 2002

This paper is aimed at surveying the method that supports logical and theoretical back grounds of electricity service pricing, to investigate whether the ESPM can reflect comprehensively the various interests of parties and persons concerned with electricity supply and demand, and analyzing the practical applicability of the model in short-term perspectives. The major findings of this study can be summarized as fellows. First, the ESPM explains what process the equilibrium price is attained through, which is the essential concept and object in evaluating the value of public enterprises or utilities and the price of electricity Second, the ESPM provides the logics and methods that can objectify the discrete price by each electricity user. Third, the ESPM presents theoretical logics and practical methods that can calculate the basic price and the variable price per electricity unit which are key concepts in the two-part tariff. Fourth, the ESPM has powerful practical applicabilities in the reasonable electricity pricing and in the explanation for the balance between parties and persons interested with electricity supply and demand.

• Journal of Engineering Education Research
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• v.19 no.3
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• pp.44-53
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• 2016

In the engineering students, MSC is the most important basic areas in education. Also, the calculus is a main subject in the MSC. So calculus has been operating the annual number of courses at the university. We introduced the concept of joint control ; the joint syllabus, test and assessment. In harsh conditions to maintain joint control system of the calculus, we built a computer-aided-system to manage web-based result processing system. In this paper, we discussed the necessity and effectiveness of joint control system for calculus.

• Proceedings of the KIEE Conference
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• 1990.07a
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• pp.351-355
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• 1990

In this paper, we proposed a software strategy of PWM inverter, and could indentify its realization by simulation and experiment. A basic concept of software is that the PWM pattern of inverter decided by the flux vector of induction motor tracing circle locus. The algorithm is charterized as a simplification of control circuit, abilitry on expressing control quintity as quantization and conpensation of quantization error and a switching pattern is decided by addition and substraction and high performance control is realized by 8 bits microprocessor.