• 한국공작기계학회논문집
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• 제18권1호
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• pp.36-41
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• 2009

This paper presents the development of a micro punching system with modified cymbal mechanism. To realize the micro punching, we introduced the hybrid system with a macro moving part and micro punching part. The macro moving part consists of a ball screw, a linear guide and the micro step motor and micro punching part includes the PZT actuators and displacement amplification device with modified cymbal mechanism. The PZT actuator is capable of producing very large force, but they provide only limited displacements which are several micro meters. Thus the displacement amplification device is necessary to make those actuators more efficient and useful. For this purpose, a cymbal mechanism in series is proposed. The finite element method was used to design the cymbal mechanism and to analyze the mode shape of the one. The displacement and mode shape error between the FEM results and experiments are within 10%. A considerable design effort has been focused on optimizing the flexure hinge to increase the output displacement and punching force.

• 한국농촌건축학회논문집
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• 제8권1호
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• pp.62-69
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• 2006

This study is based on the ecological design method related with the Building Landscape in Coastal Area, basically Building Landscape design theories are affected the visual distance and visual area. The results derived of this study are as follows. First, We established design method of Building Landscape in Coastal Area in consideration of Ecological Environment that is purposed by means of the Normative theory study analysis and contents analysis related with Landscape and Architecture planning theory. Second, We can define 'Micro Landscape', 'Urban Landscape', and 'Wide Landscape'. 'Micro Landscape' are 'Near view'. 'Urban Landscape' are related 'Middle-distance view' and 'Long-distance view'. 'Wide Landscape' are related 'High & Long-distance view'. Third, We can also define 'Ecological Mode', 'Formal Aesthetic Mode', 'Psychological Mode', and 'Semiotical Mode' by the dimensions of macro scale. finally, we define 48 detailed factors types of 3 visual Area of Building Landscape in Coastal Area by the dimensions of micro scale.

• 한국전자파학회논문지
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• 제20권10호
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• pp.1031-1041
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• 2009

본 논문에서는 다중 대역에서 매크로-마이크로 주파수 튜닝이 가능한 소형의 패치 모노폴 안테나를 소개하였다. 제안된 재구성 안테나는 PCB 기판(FR-4: $\varepsilon_r=4.4$ and tan $\delta=0.02$) 위에 미앤더(meander) 형태의 안테나로 설계하였고, Wibro(2.3~2.4 GHz)와 WLAN a/b(2.4~2.5 GHz/5.15~5.35 GHz)대역에서 일정한 이득을 유지하면서 각각의 서비스 대역에서 동작한다. 두 개의 다이오드, 핀 다이오드와 버렉터 다이오드가 주파수 튜닝을 위해 안테나 상에 내장되었으며, 핀 다이오드는 2 GHz와 5 GHz의 대역을 스위칭(매크로 튜닝)하기 위해 사용되었으며, 버렉터 다이오드는 2.3~2.5 GHz와 5.15~5.35 GHz의 서비스 대역 내 미세 주파수 튜닝(마이크로 튜닝)을 위하여 사용되었다. 또한, 두 주파수 대역(2 GHz와 5 GHz) 사이에서의 불요 공진(spurious resonance)은 미앤더(meander) 사이의 갭을 조정하여 제거되었다. 안테나는 각각의 서비스 대역에서 2 dBi 이상의 일정한 이득을 보인다. 제안된 안테나의 측정 결과는 매크로-마이크로 주파수 튜닝 기술이 재구성 가능한 다중 대역 다중 모드(Multi-Mode Multi-Band: MMMB) 무선 통신 시스템에서 유용하게 사용될 수 있음을 보여준다.

• Steel and Composite Structures
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• 제20권3호
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• pp.719-729
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• 2016

There are great needs of simple but reliable mechanical nonlinear behavior analysis and performance evaluation method for frames constructed by steel and concrete composite beams or columns when the structures subjected extreme loads, such as earthquake loads. This paper describes an approach of simplified macro-modelling for composite frames consisting of steel-concrete composite beams and CFST columns, and presents the performance evaluation procedure based on the pushover nonlinear analysis results. A four-story two-bay composite frame underground is selected as a study case. The establishment of the macro-model of the composite frame is guided by the characterization of nonlinear behaviors of composite structural members. Pushover analysis is conducted to obtain the lateral force versus top displacement curve of the overall structure. The identification method of damage degree of composite frames has been proposed. The damage evolution and development of this composite frame in case study has been analyzed. The failure mode of this composite frame is estimated as that the bottom CFST columns damage substantially resulting in the failure of the bottom story. Finally, the seismic performance of the composite frame with high strength steel is analyzed and compared with the frame with ordinary strength steel, and the result shows that the employment of high strength steel in the steel tube of CFST columns and steel beam of composite beams benefits the lateral resistance and elasticity resuming performance of composite frames.

• Journal of East Asia Management
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• 제4권2호
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• pp.39-62
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• 2023

Online and offline mixed teaching mode has become an important way to promote the connotative development of higher education. Under the background that offline teaching has become mature, in order to further promote the development of online education, and promote the implementation of the mixed teaching mode, to mix and to provide basis for the construction of the mixed teaching mode, this study takes the online learning effect as the evaluation basis, adopts the online questionnaire survey to conduct statistical analysis of the online learning behavior of 2213 college students, and discusses the differentiation phenomenon of online learning groups from the micro, meso and macro perspectives. It is found that there are significant differences in the online learning effect of college students in terms of the type of learning platform, whether the school implements the online offline mixed teaching mode, education background, grade (bachelor's degree), and region. Colleges and universities should strengthen the promotion of online and offline mixed teaching mode; The online learning platform should improve the platform function and strengthen the functional differentiation design of learning resources for students. Education departments pay attention to the learning effect of online learners in different regions, and bridge the gap in regional education.

• 대한교통학회지
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• 제13권4호
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• pp.79-103
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• 1995

The elasticity of a model is considered most important. Without showing the proper elasticity any model cannot provide useful information for decision making. This paper demonstrates a macro model which can generate dynamic transport informations every 15 minutes. Without the Wardrop principles and the monotonicity assumptions for the link travel time and link volume relationship, the basic elements of this new modeling approache are composed of link density simulation, stochastic incremental route choice, departure time choice, destination choice and mode choice. The elasticity of the proposed model is examined based on elasticity equations and simulation results. Also the transferability from a mega city like Seoul to a big city like Daejon is demonstrated for the choice model. The issues centering around the dynamic relations among density(k), speed(u), and flow rate(v) are also discussed for the modeling of highly congested situations.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권11호
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• pp.4331-4346
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• 2015

The femtocell network, which is designed for low power transmission and consists of consumer installed small base stations, coexists with macrocells to exploit spatial reuse gain. For its realization, cross-tier interference mitigation is an important issue. To solve this problem, we propose a joint access and power control scheme that requires limited information exchange between the femto and macro networks. Our objective is to maximize the network throughput while satisfying each user's quality of service (QoS) requirement. To accomplish this, we first introduce two distributed interference detection schemes, i.e., the femto base station and macro user equipment based schemes. Then, the proposed scheme dynamically adjusts the transmission power and makes a decision on the access mode of each femto base station. Through extensive simulations, we show that the proposed scheme outperforms earlier works in terms of the throughput and outage probability.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.I
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• pp.255-258
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• 2005

In this study, new types of counter electrode discharge cells for PDP were designed. The counter electrode discharge cells were designed to realize long-gap discharge mode, low firing voltage and moderate conductance for evacuation and sealing process of the panel. In order to test the concept of the design, macro discharge cells were prepared and the discharge characteristics were evaluated. The results indicate that discharge behavior may be modified significantly by changing the morphology of discharge cells.

• 대한가정학회지
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• 제34권2호
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• pp.367-378
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• 1996

The purpose of this study was to utilize of the CAD system in pattern making process for women's bodice sloper, especially in education of the drafting. Accumark 540 System was used for this study. The drafting program was developed by the use of macro program in CAD system. The results from this study : 1. The Lim Won Ja's system of bodice sloper was selected in this study. The hand drafting of the system was arranged developing the macro program of bodice sloper. 2. The program consists of eight subprograms I sequence of the drafting order. In running this developed program, proper figure is drafted by inputing data. And the drafting process is automatically presented in interactive mode. 3. It has been developed to input the function of French Curve Ruler to increase the effectiveness of curved line treatment. The program can also be used in the curve part to present the manualy sensible function. 4. In case of education of drafting bodice sloper, the program provides the high accuracy, efficiency and a strong interest nterest in pattern making process by utilizing CAD system.

• 한국광학회지
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• 제8권2호
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• pp.134-141
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• 1997

기존의 .lambda.=1.31.mu.m에서 분산 최적화된 광통신시스템을 .lambda.=1.55.mu.m 광전송시스템으로 향상시키는데 필요한 분산보상 단일모드 광섬유(DCF)를 설계하였다. 총분산이 .lambda.=1.55.mu.m에서 큰 마이너스 분산치를 갖는 굴절율 분포를 얻기 위해 포물선 분포-이중클래드 광섬유의 분산특성을 해석하였다. 광섬유 스칼라 파동방정식으로부터 분산특성을 얻기 위해 1차원 유한요소법을 적용하였다. Reel에 감긴 DCF의 macro-bending에 의한 손실을 적절히 제한하기 위해, L $P_{01}$모드의 차단 파장이 .lambda.=1.80.mu.m이상이 되도록 설계하였다. 이 조건에 맞는 굴절율분포의 .lambda.=1.55.mu.m에서 분산의 하한치는 약 -120 ps/nm.km정도로 제한됨을 볼 수 있었다.다.