• Journal of Fashion Business
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• v.9 no.3
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• pp.37-46
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• 2005

The purpose at this study was to investigate how component factors at SCM affect the performance at textile and apparel firms in a competitive market. For the methodology at this study, the questionnaire was developed based upon the literature review. 150 questionnaires were distributed to the CEOs, CMOs, and experts who operate SCM in textile and apparel firms. The returned usable 85 were analyzed by SPSS10.0 with multiple regression analysis and Cronbach's Alpha for internal consistency and reliability. The performance at the textile and apparel firms that adopted SCM was affected by information system, partnership, and business environment in a descending order. For details, the performance of the textile and apparel firms that adopted SCM was affected by computerization, information sharing, CEO's concern, alliance, and support in a descending order.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.595-600
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• 2007

This paper presents a new jetting dispenser driven by a piezoelectric actuator at high operating frequency to provide very small dispensing dot size of adhesive in modern semiconductor packaging processes. After describing the mechanism and operational principle of the dispenser, a mathematical model of the structured system is derived by considering behavior of each component such as piezostack and dispensing needle. In the fluid modeling, a lumped parameter method is applied to model the adhesive whose rheological property is expressed by Bingham model. The governing equations are then derived by integrating the structural model with the fluid model. Based on the proposed model, dispensing performances such as dispensing amount are investigated with respect to various input trajectories.

• Journal of the Korea Institute of Military Science and Technology
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• v.10 no.1
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• pp.94-100
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• 2007

MVRS's measuring principles are based on the Doppler principle. It measures the velocities near the muzzle using the doppler signal output from the antenna and then predicts the velocity of the bullet leaving the muzzle by performing the regression analysis on previous measured velocities. There are a number of error sources when calculating the muzzle velocity. Antenna has long term frequency stability error and the doppler signal from the antenna has noise. These two error sources influence the accuracy of estimated velocities from the doppler signal. Estimated velocity errors result in the random error of data statistics. And when performing a regression analysis these random error components are transferred to the fitting error component. This study also analyzed the error components according to the hardware limitations of MVRS-700 and the signal processing method, and presented the calculated uncertainty of muzzle velocity.

• Industrial Engineering and Management Systems
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• v.13 no.1
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• pp.29-42
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• 2014

Extensive research has been conducted on supplier evaluation and selection as a strategic and crucial component of supply chain management in recent years. However, few articles in the previous literature have been dedicated to the use of fuzzy inference systems as an aid in decision-making. Therefore, this essay attempts to demonstrate the application of this method in evaluating suppliers, based on a comprehensive framework of qualitative and quantitative factors besides the effect of gradual coverage distance. The purpose of this study is to investigate the applicability of the numerous measures and metrics in a multi-objective optimization problem of the supply chain network design with the aim of managing the allocation of orders by coordinating the production lines to satisfy customers' demand. This work presents a dynamic non-linear programming model that examines the important aspects of the strategic planning of the manufacturing in supply chain. The effectiveness of the configured network is illustrated using a sample, following which an exact method is used to solve this multi-objective problem and confirm the validity of the model, and finally the results will be discussed and analyzed.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.5 no.3
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• pp.54-63
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• 1991

This paper describes an effort to develope a microcomputer-based parameter measurement system for a brushless DC motor. Back EMF equation is derived from back EMF waveform of a brushless DC motor. To minimize error the due to the ripple component in the measured armature current, digital averaging filter is employed. The whole identification process of signal generation, measurement parameter determination is fully automated. A new identification algorithm for the brushless DC motor parameters is developed. New parameter correction method is proposed using the deadzone current and the time to reach the peak current. In the proposed correction method, the measured current is in excellent agreement with the estimated current.

• Journal of Power Electronics
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• v.16 no.4
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• pp.1541-1550
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• 2016

This paper presents a theoretical analysis and comparisons of active power filter (APF) and hybrid power filter (HPF) systems, given terminal constraints of harmonic compensations in nonlinear loads. Despite numerous publications for the two types of filters, the features and differences between them have not been clearly explained. This paper presents a detailed analysis of the operations of a HPF inverter along with those of passive power filters (PPFs). It also includes their effects on the power factor at the grid. In addition, a theoretical analysis and a systematic comparison between the APF and HPF systems are addressed based on system parameters such as the source voltage, output power, reactive component size, and power factor at the grid terminals. The converter kVA ratings and dc-link voltage requirements for both topologies are considered in the presented comparisons

• The Transactions of the Korean Institute of Power Electronics
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• v.23 no.4
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• pp.265-272
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• 2018

This paper proposes a new control method for the supercapacitor (SC) to compensate the pulsed load and to enhance the power quality of the DC microgrid. By coordinating the operating frequency, the SC is controlled to handle the surge current, while the low-frequency current component is dealt with by the remaining sources in the system. The operation mode of the SC unit is automatically changed based on the state of charge and DC bus voltage level. Meanwhile, the mismatch in the power demand is covered by the SC unit by regulating the DC bus voltage level. The effectiveness of the proposed method is verified experimentally by the prototype with two distributed generators and one SC unit.

• Journal of Power Electronics
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• v.18 no.4
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• pp.997-1006
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• 2018

This paper proposes a transformerless photovoltaic (PV) power converter system based on the DC/AC boost inverter, which can solve the leakage current and second-order ripple power issues in single-phase grid-connected PV inverters. In the proposed topology, the leakage current can be decreased remarkably since most of the common-mode currents flow through the output capacitor, by-passing parasitic capacitors, and grounding resistors. In addition, the inherent ripple power component in the single-phase grid inverter can be suppressed without adding any extra components. Therefore, bulky electrolytic capacitors can be replaced by small film capacitors. The effectiveness of the proposed topology has been verified by simulation and experimental results for a 1-kW PV PCS.

• Journal of KIISE:Databases
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• v.28 no.2
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• pp.188-203
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• 2001

멀티데이터베이스 시스템(multidatabase system)에서 여러 요소 데이터베이스(component database)에 대한 통합된 접근을 제공하기 위해서는 의미 이질성(semantic heterogeneity)이 탐색되고 해결되어져야 한다. 즉, 멀티데이터베이스 시스템은 각 요소 데이터베이스가 가지고 있는 정보의 의미를 이해하고 의미적으로 동등한 또는 유사한 정보들을 식별할 수 있어야 한다. 또한, 멀티데이터베이스 시스템은 사용자로 하여금 실세계의 동일한 정보를 가지고 있는 여러 다른 데이터베이스로부터 원하는 정보를 용이하게 획득할 수 있도록 해야 한다. 본 논문에서는, 요소 데이터베이스간의 의미 이질성을 탐색하고 해결하기 위하여 정보가 갖고 있는 개념간 의미관계에 기반한 의미망(semantic network)을 구축한다. 또한 의미질의어(semantic query language)를 제공하여 사용자가 스키마에 대한 사전 지식이 없이도 여로 자율적인 데이터베이스로부터 원하는 정보를 용이하게 획득 할 수 있도록 한다.

• Proceedings of the Korean Information Science Society Conference
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• 2002.04b
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• pp.391-393
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• 2002

내장형 시스템의 경쟁력 향상을 위해 제품의 신속한 설계는 매우 중요하다. 내장형 시스템 설계에 사용하는 기존 Statechart 도구는 Statechar 재사용 측면에서 복사해서 붙이는 방법을 이용하고 있다. 이러한 방법은 새로운 제품 선계 시 시스템 개발자의 불필요한 투자가 요구되는 문제점이 있다. 본 논문은 이미 작성된 Statechart를 효율적으로 재사용하기 위해 컴포넌트 기능을 기존 도구 기능에 새롭게 추가함으로써 신제품의 신속한 설계를 지원하는 도구를 구현한다. 또한, 본 논문에서는 이러한 컴포넌트 기능을 추가하기 위해 컴포넌트 사용상 규약인 계약(contact)을 Statechart 구현에 적합하도록 재구성하였다. 구현된 컴포턴트 지원 Statechart 도구는 컴포넌트를 이용하여 새로운 제품의 신속한 설계를 지원함으로써 제품의 생명주기를 단축함은 물론 신제품의 시장적기진입을 제공할 수 있고, 이로써 제품의 경쟁력 향상에 도움 줄 수 있다.