• 반도체디스플레이기술학회지
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• 제12권2호
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• pp.19-25
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• 2013

Extrusion is one of the most important operations in the polymer-processing industry. Balancing the distribution of flow through a die to achieve a uniform velocity distribution is the primary objective and one of the most difficult tasks of extrusion die design. If the manifold in a coat-hanger die is not properly designed, the exit velocity distribution may be not uniform; this can affect the thickness across the width of the die. Yet, no procedure is known to optimize the coat hanger die with respect to an even velocity profile at the exit. While optimizing the exit velocity distribution, the constraint optimization used in this work with allowable pressure drop in the die; according to this constraint we can control the pressure in the die. The computational approach incorporates three-dimensional finite element simulations software STAR-CCM+. These simulations are used with numerical optimization to design polymer coat hanger dies with pressure drop, uniform velocity and temperature variation across the die exit.

• 한국컴퓨터정보학회논문지
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• 제19권5호
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• pp.53-60
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• 2014

최근 IT 기술의 급속한 발전으로 시설물의 설비진단과 관련된 융합 기술의 발전이 가속화되어 가고 있으며, 설계에서 유지, 보수 단계에 이르는 모든 관련 정보를 효율적으로 처리하고 관리할 수 있는 기법에 대한 연구가 요구되고 있다. 본 논문에서는 IT융합기술을 기반으로 설비 진단 및 시설물에 대한 복합정보를 효율적으로 처리하는 처리기법을 제안하고 실시간 복합정보 관리시스템을 설계하였다. 제안된 시스템의 성능을 평가하기 위해 특정 시설물을 대상으로 실시간 관리시스템을 설계하였으며, 결과를 분석하여 제안된 기법의 성능이 우수함을 입증하였다.

• 한국정보처리학회논문지
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• 제7권10호
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• pp.3148-3154
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• 2000

본 논문의 시스템은 학사업무 중의 하나인 온라인 수강신청 시스템을 설계 및 구현하였다. 이를 위해, PC 서버의 리눅스 환경에서 아파치 웹 서버와 데이터베이스 엔진으로 MySQL을 사용하였다. 또한, 데이터베이스 연동을 위해 최근에 각광받고 있는 인터넷 서버 기반 스크립트 언어인 PHP를 사용하였다. 수강신청의 특성상 단기간에 동시 접속으로 인한 심각한 과부하 문제가 발생하므로 불필요한 인터페이스를 최소화하여 수강신청을 할 수 있도록 고려하였다. 관리자 측면에서도 특정 업무를 위한 데이터베이스의 공개 범위를 한정하여 전용 서버를 분리·구축함으로써 부하 균형, 최적의 자료 보안 및 자료 관리 환경을 구축하였다.

• EDISON SW 활용 경진대회 논문집
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• 제5회(2016년)
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• pp.183-189
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• 2016

In this paper, an optimization study on a helicopter rotor blade cross-section was made. Generalization was made to the baseline cross-section to simplify the analysis. To have better performance in aeroelastic response, with the aerodynamic center being the origin of the baseline, the distance between aerodynamic center and shear center, and the distance between mass center and shear center of the blade were minimized. For efficient searching of optimum solutions over the design space, grid search method, which is a method of graphical search was used. Two design variables, radius of balancing weight at leading edge, and offset of the spar from leading edge were selected for the study. Cubic spline interpolation method was used to accommodate searching of the optimum solution. 2-Leveled searching system was devised in accordance with the interpolation method. Optimum solution was found to show 6% decrease in both distance between aerodynamic center and shear center, and mass center and shear center to the baseline.

• 국제물리치료학회지
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• 제11권1호
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• pp.1992-1998
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• 2020

Background: The foot drop stimulator is designed to improve the walking ability of foot drop in patients after stroke, however, studies on clinical effects are still lacking. Objective: To investigate the effect of a foot drop stimulator on the walking and balancing abilities of foot drop patients after a stroke. Design: One-Group (Pretest-Posttest) Design. Methods: All subjects walked in all three conditions: foot drop stimulator (FDS) ankle foot orthosis (AFO) and barefoot. Primary outcome measures were assessed for walking and balance using a 10-m walking test (10MWT) and a timed up and go test (TUG). Secondary outcome measures consisted of a brief user interview, and the patients recorded the advantages and disadvantages of each condition. Results: FDS, AFO, and barefoot conditions showed a statistically significant difference in 10MWT and TUG (P<.001) as a result of comparing three conditions. FDS and AFO were significantly different from the barefoot condition as post-hoc results; however, there was no significant difference between the two conditions (P>.05). Conclusion: In this study, the foot drop stimulator contributed to improving the balance ability, and the walking ability was similar to the effect of the ankle-foot orthosis.

• 국제물리치료학회지
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• 제11권1호
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• pp.1950-1953
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• 2020

Background: Ankle instability usually occurs after stroke, and contributes to unsafe walking and associated risk of falling in the affected patients. Objective: To investigate the effects of kinesiology taping (KT) on gait and balance ability (center of pressure, CoP) in patients with ankle instability after stroke. Design: One group, pre-post design. Methods: A total of 11 patients with ankle instability after stroke were enrolled. In all subjects, the gait and balance ability were assessed under 2 conditions: KT and barefoot. Gait and balance ability was assessed using GAITRite system and FDM-S platform. Results: Comparison between KT and barefoot condition, KT condition was significantly higher in velocity, cadence, step length, and stride length than barefoot condition (P<.05). KT condition was significantly lower in CoP path length and sway speed than barefoot condition (P<.05). Conclusion: KT indicated potential as a helpful method for walking and balancing ability in patients with ankle instability after stroke. Therefore, this study recommends KT as an option applicable to the stroke with ankle instability.

• 설비공학논문집
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• 제16권3호
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• pp.265-272
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• 2004

Based on the T-method, a new scheme for predicting air flow rate distribution in a bathroom exhaust system is developed. Introduction of individual duct route enables us to disintegrate a complicated multi-fan ductwork into a set of simultaneous single-fan subsystems. The scheme is validated via the analysis of a well-posed test problem, showing physical consistency. In order to demonstrate the utility and capability of our method, the bathroom ventilation system in a 20-story residential building is selected as an example. Under the typical design condition, the air flow rate of each exhaust fan at the balancing point is successfully predicted, and such information can lead to an engineering estimation for the overall system performance. While some deficiencies in ventilation are found at bathrooms at lower floors with 6mmAq-rated exhaust fans, they disappear over the whole building by using fans of enhanced static pressures, 7 and 8mmAq. Finally the present scheme seems to be useful for practical design of multi-branched, multi-fan ventilation systems.

• 반도체디스플레이기술학회지
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• 제21권4호
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• pp.132-137
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• 2022

In this paper, we have studied the quadrature error reduction for the single drive 3-axis MEMS Gyroscope. There was a limitation of the previous study which is the z-axis quadrature error was large. To reduce this value, design methodologies were presented. And the methodologies included a different mesh application, z-rate spring structure change, and mass compensation for balancing of the structure. We conducted the modal analysis, drive mode analysis and sense mode analysis using COMSOL Multiphysics. As a result, a drive resonant frequency was 26003 Hz, with the x-sense, y-sense, z-sense being 26749 Hz, 26858 Hz, 26920 Hz, respectively. And the Mechanical sensitivity was computed at 2000 degrees per second(dps) input angular rate while the sensitivity for roll, pitch, and yaw was computed 0.011, 0.012, and 0.011 nm/dps respectively. And z-axis quadrature error was successfully improved, 2.78 nm to 0.95 nm, which the improvement rate was about 66 %.

• 한국멀티미디어학회논문지
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• 제25권8호
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• pp.1075-1084
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• 2022

Internet of Things(IoT) has become a key available technology for efficiently implementing device to device(D2D) services in various domains such as smart home, healthcare, smart city, agriculture, energy, logistics, and transportation. A lightweight publish/subscribe(Pub/Sub) messaging protocol not only establishes data dissemination pattern but also supports connectivity between IoT devices and their applications. Also, a Pub/Sub broker is deployed to facilitate data exchange among IoT devices. A scalable edge-based publish/subscribe (Pub/Sub) broker overlay networks support latency-sensitive IoT applications. In this paper, we design a hypercube grid quorum(HGQ) for distributed Pub/Sub systems based IoT applications. In designing HGQ, the network of hypercube structures suitable for the publish/subscribe model is built in the edge layer, and the proposed HGQ is designed by embedding a mesh overlay network in the hypercube. As their applications, we propose an HGQ-based mechansim for dissemination of the data of sensors or the message/event of IoT devices in IoT environments. The performance of HGQ is evaluated by analytical models. As the results, the latency and load balancing of applications based on the distributed Pub/Sub system using HGQ are improved.

• 한국의류산업학회지
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• 제23권5호
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• pp.545-558
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• 2021

This research analyzed the Chinese style design embodied in the collections of the new generation of fashion designers shown during the Shanghai Fashion Week to improve the understanding of Chinese style and the modernization of Chinese design. The research questions were 1) studying the development of the Chinese fashion industry chronologically and investing young designers' current situation, 2) investigating young designers' awareness of Chinese style and analyzing Chinese style design in collections. A literature and case study were conducted as the research method. The literature study focused on the books about the Chinese fashion industry and history, newspaper, articles, and so on. The case study was conducted among 63 Chinese style collections in 2016-2020 SFW by investigating fashion magazine reviews, articles, and so on. The findings are as follows: 1) Young Chinese fashion designers' awareness of Chinese style has three characteristics; the nonmaterial tendency from decreasing stereotyped images, combination of traditional culture and local youth culture, and commercialization with trends. 2) Chinese elements, including natural, character, and cultural elements were predominantly used in the concept, pattern, and shape. Nonmaterial characteristics were identified in concept, cultural combination characteristics in concept, shape, color, material, and pattern, and trend commercialization in shape, color, and pattern. In conclusion, Chinese young fashion designers had strong national consciousness and new awareness of Chinese style fashion in decreasing the stereotyped images of China. Thus, they used more varied expressions. Meanwhile, they faced difficulties in expressing nonmaterial Chinese elements by balancing them with Chinese style and globalization.