• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2006년도 하계종합학술대회
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• pp.215-216
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• 2006

In this paper, the antenna the with linear active phased array of $1{\times}16$ operated in DBS band was designed. The antenna was composed of sixteen radiating elements, sixteen active channels and five Wilkinson power combiners with 4-channel inputs, a digital control board and a stabilizing DC bias board. The radiating element of the array has the structure of a microstrip stack patch with a left-hand circular polarization. And, each active channel consists of a low noise ampilifier, a 3-bit digital phase shifter and a variable analog attenuator. The breadboard of linear active phased array antenna was also fabricated to test the electrical performances. The radiation patterns of the antenna were measured after correcting initial phases of each active channel in aechoic chamber. And also, the beam scanning chracteristcs of $10^{\circ}$, $20^{\circ}$, $30^{\circ}$ were measured.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권4호
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• pp.1904-1921
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• 2019

In this paper, we investigate the problem of secure communications in multiple-input-multiple-output interference networks from the perspective of physical layer security. Specifically, the legitimate transmitter-receiver pairs are divided into different categories of active and inactive. To enhance the security performances of active pairs, inactive pairs serve as cooperative jammers and broadcast artificial noises to interfere with the eavesdropper. Besides, active pairs improve their own security by using joint transceivers. The encoding of active pairs and inactive pairs are designed by maximizing the difference of mean-squared errors between active pairs and the eavesdropper. In detail, the transmit precoder matrices of active pairs and inactive pairs are solved according to game theory and linear programming respectively. Experimental results show that the proposed algorithm has fast convergence speed, and the security performances in different scenarios are effectively improved.

• 한국의류산업학회지
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• 제17권6호
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• pp.881-894
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• 2015

The silver generation have clothing style of optimal daily life comparing than young generation because they do not participate a specific sport event but daily- life exercise. As the human body ages, the figure of the silver generation shows different body shape because upper body changes to curved figure including the belly and waist part. Therefore, clothing characteristics for the silver generation should be considered with proper function, design and textiles to optimize body movement. This study investigated various exercise types according to motion analysis of the silver generation in order to develop the design of the active T-shirts reflecting the structural properties and providing the optimum exercise circumstance. The results to consider design needs are as followed; As the T-shirts design for the flexible exercise which required frequent movement of upper body such as bending and waist twisting during body stretching, a stretch fabric applied to the waist part considering T-shirts allowance and length to make extreme elongation and support for well-fitting appearance of the T-shirts. As the T-shirts design for the instantaneous reactionary exercise, high elastic four-way stretch fabric is applied to the part of arm hole to optimize skeletal and muscle movement for entire body and arm work. As the T-shirts design for the endurance exercise such as climbing, cycling, and walking, the shoulder line of the back part has cutting line allowance to make optimum movement of the upper body but no change of the waist part.

• 한국소음진동공학회논문집
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• 제26권2호
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• pp.165-171
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• 2016

A prosthetic knee for above-knee (AK) amputee is categorized into passive and active type. The passive prosthetic knee is generally made by elastic material. Although AK amputee can easily walk by using passive prosthetic leg, knee joint motions are not similar to ordinary persons. The active prosthetic leg can control the knee angle owing to the actuator and microprocessor. However, the active type is not cost-effective and the stability may be lost due to the malfunction of sensors. In order to resolve these disadvantages of passive and active type, a semi-active prosthetic knee which can control the knee angle is proposed in this work. The proposed semi-active one requires a less input energy but provides active type performance. In order to achieve this goal, in this work, a semi-active prosthetic knee using magneto-rheological (MR) damper for AK amputees is designed. The MR damper can support the weight of body by using less energy than actuator of active prosthetic. It can control knee angle by inducing the magnetic field at the time of stance phase. This salient characteristic is evaluated and presented in this work.

• 유공압시스템학회논문집
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• 제7권4호
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• pp.32-38
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• 2010

A semi-active suspension is an automotive technology that controls the vertical movement of the vehicle while the car is driving. The system therefore virtually eliminates body roll and pitch variation in many driving situations including cornering, accelerating, and braking. This technology allows car manufacturers to achieve a higher degree of both ride quality and car handling by keeping the tires perpendicular to the road in corners, allowing for much higher levels of grip and control. An onboard computer detects body movement from sensors located throughout the vehicle and, using data calculated by opportune control techniques, controls the action of the suspension. Semi-active systems can change the viscous damping coefficient of the shock absorber, and do not add energy to the suspension system. Though limited in their intervention (for example, the control force can never have different direction than that of the current speed of the suspension), semi-active suspensions are less expensive to design and consume far less energy. In recent time, the research in semi-active suspensions has continued to advance with respect to their capabilities, narrowing the gap between semi-active and fully active suspension systems. In this paper we are studied the characteristics of vehicle movement during the field test with conventional and semi-active suspension system.

• 스마트미디어저널
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• 제8권1호
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• pp.67-73
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• 2019

본 연구는 4차 산업혁명 시대 직업교육에 대응하기 위하여 핵심역량 중 직무능력을 향상 시킬 수 있는 액티브러닝과 퍼실리테이션(Active Learning&Facilitation) 융합 교육프로그램을 연구하였다. 연구방법으로는 '문제해결 능력'을 키워주는 Active Learning의 장점과 창의적 아이디어 발상을 위한 Facilitation의 장점을 융합하여 앱 디자인 교과목에 적용하고 학생들의 만족도 조사를 통해 교육의 효과성을 검증하였다. 모바일 환경에 익숙한 학생의 특성을 반영하여 앱 콘텐츠를 기획하고, 데이터 시각화를 위한 UI 디자인을 수행하여 S/W분야의 스킬을 강화할 수 있도록 하였다. 모든 수행과정은 팀 프로젝트(PBL)로 운영되었다. 연구결과 액티브러닝과 퍼실리테이션 융합 교육프로그램은 전문대학교육이 요구하는 foundation skills, competencies을 향상할 수 있었다. 더불어 산업현장과 대학 간 교육격차를 줄일 수 있을 것으로 기대한다.

• 한국산학기술학회논문지
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• 제15권11호
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• pp.6804-6809
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• 2014

본 논문에서는 저전압, 저전력 아날로그 신호처리 시스템에 활용할 수 있도록 전류 차동 트랜스컨덕턴스 증폭기(CDTA)를 사용하여 대역통과 필터를 설계하였다. 대역통과 필터는 그라운딩 인덕터와 플로팅 능동 인덕터를 사용하여 설계하였고, 설계된 능동 인덕터는 각각 두 개 또는 세 개의 CDTA를 활용하여 구성하였다. 본 논문에서 설계된 능동 인덕터를 활용하여 대역통과 필터를 구성할 때, 소자 값 들을 조정하기 위한 외부의 추가적인 정합회로의 필요 없이 필터를 구현할 수 있다는 장점이 있다. 설계된 능동 대역통과 필터 특성의 검증은 HSPICE 시뮬레이션 프로그램을 활용하였다. 시뮬레이션결과, 설계된 필터는 10MHz의 중심주파수, 통과대역에서는 -2.5dB의 감쇄율을 가진 9.5~10.5MHz의 대역폭을 얻을 수 있었으며, 차단대역에서는 8MHz이하와 17MHz이상에서 -50dB의 감쇄율을 가진 대역통과 특성을 얻을 수 있다.

• 한국의류산업학회지
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• 제11권3호
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• pp.371-382
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• 2009

In this study, I examined the psychological visual effect and clothes preference by clothes designs for the mid-aged Korean and American women's somatotypes. The psychological visual effects of each somatotypes' clothes are like these. First, the primary factors for psychological visual effect were analyzed into 5, neat, feminine, polished, modern and active. Second, in thin somatotype, Korean evaluated that china collar and V-neckline are the least feminine, and stand collar is the most polished and the modernest. American evaluated that V-neckline is the most feminine, and tailored collar is the modernest. It shows that there's the difference of culture. In standard somatotype, Korean thought stand collar with pants is the neatest, but tailored collar and china collar with pants are not neat. Contrary, they thought tailored collar with skirt is the neatest and stand collar with skirt is not neat. American thought tailored collar with skirt is the neatest and modernest. The neat visual effects are evaluated differently according to the clothes' styles of bottom. In obesity, Korean evaluated that tailored collar with skirt is the neatest and modernest, but stand collar with skirt is not modern. Stand collar with pants is the modernest, but tailored collar with pants is the least modern and active. American evaluated that round neckline with pants is not neat, modern and active, and round neckline with skirt is the modernest and the most active. So neckline's visual effects are differently showed by culture and the clothes' styles of bottom.

• 한국인터넷방송통신학회논문지
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• 제24권1호
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• pp.23-30
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• 2024

본 논문에서는 광대역 특성을 가지는 능동위상배열 안테나의 설계, 검증 및 분석에 대하여 기술하였다. 능동위상 배열 안테나를 항공기 혹은 미사일에 적용하려면 배열 안테나의 소형화 및 광각 빔조향 특성을 확보하는 것은 피할 수 없는 안테나 설계 고려 사항이 될 수 있다. 특히 전자적으로 광각 빔조향 시 능동반사계수 특성은 시스템의 생존 및 성능 측면에서 최소화되어야 하는 설계 파라미터이다. 광대역 특성 및 광각 빔조향에 적합한 복사 소자로 본 논문에서는 Step Flared Notch(SFN)를 적용한 배열 구조를 설계하고 구좌표계 θ 각도 기준 최대 40° 빔조향에 따른 능동반사계수를 최소화하였다. 복사소자의 대역폭은 Ka대역에서 능동반사 기준으로 3GHz를 확인하였다. 또한 실제 제작된 8by8 배열 안테나는 근접전계 시험을 통해 복사소자의 단일 패턴을 측정하고, 수학적으로 합성하여 탐색기 시스템에 사용하는 송/수신빔을 예측하여 성능을 분석하였다.

• 한국건설관리학회논문집
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• 제17권3호
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• pp.3-12
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• 2016

최근 건설업계의 해외진출이 불가피한 상황에서 국내 설계도면의 경쟁력은 뒤처져있다는 평가를 받고 있다. 따라서 객관적 도면평가를 통해 국내도면수준을 파악하고, 설계경쟁력 확보방안을 마련하고자 한다. 실시설계도면을 기반으로 설계속성을 도출하고, 기존 유사연구와 전문가 인터뷰를 거쳐 속성을 보완한 뒤, 이들을 평가항목으로 Likert척도와 FMEA기법을 이용하여 실무자를 대상으로 설문조사를 실시하였다. 그 결과 국내도면의 상대적 수준에 대한 시공사와 설계사의 의견이 다르고, 중요성을 인지하는 속성이 상이함을 확인하고 그 이유를 분석하였다.