• 한국전자파학회논문지
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• 제22권1호
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• pp.98-105
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• 2011

최대 비 전송 기법에 비해 송신단의 고출력 증폭기에서 발생하는 비선형 왜곡 전달 특성에 강인한 QEGT 코드북 기반의 동 이득 전송 기법에 대해 개선된 인덱스 검색 기법을 제안, 이를 MIMO-OFDM 시스템에 적용한다. 제안하는 검색 기법은 QEGT 코드북을 Q개의 인덱스들로 구성된 M개의 그룹으로 분할한 후, 선택된 최적의 그룹 내 인덱스들 중에서 피드백 인덱스를 결정하는 것으로 기존 검색 기법에 비해 피드백 인덱스 결정을 위한 전체 계산량이 감소하는 장점이 있다. Monte-Carlo 시뮬레이션을 통해 송신 안테나 수가 3~7인 경우, 인덱스 검색 수가 감소하면서도 기존 검색 기법과 거의 동일한 성능을 보임을 확인한다.

• 한국시뮬레이션학회:학술대회논문집
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• 한국시뮬레이션학회 2002년도 추계학술대회 논문집
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• pp.163-170
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• 2002

Terrain surfaces have to be modeled in very detail and wheel-surface contacting geometry must be well defined in order to obtain proper ground-reaction and friction forces for realistic simulation of off-road vehicles. Delaunay triangulation is one of the most widely used methods in modeling 3-dimensional terrain surfaces, and T-search is a relevant algorithm for searching resulting triangular polygons. The T-search method searches polygons in successive order and may not allow real-time computation of off-road vehicle dynamics if the terrain is modeled with many polygons, depending on the computer performance used in the simulation. In order to accelerate the searching speed of T-search, a terrain database of triangular polygons is modeled in multi-levels by adopting the LOD (Level of Detail) method used in realtime computer graphics. Simulation results show that the new LOD search is effective in shortening the required computing time. The LOD search can be even further accelerated by introducing an NN (Neural Network) algorithm, in the cases where a appropriate range of moving paths can be predicted by cultual information of the simulated terrain, such as lakes, houses, etc.. Numerical tests show that LOD-NN search almost double the speed of the original T-search.

• 대한인간공학회지
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• 제32권3호
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• pp.253-258
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• 2013

Objective: This study investigates user performance and user perceptions of dynamic Chinese text displays (Leading display and RSVP display) when users search for target information. Background: Today, information searching with dynamic displays is widely used in TV programs, on Internet advertisements, for traffic information systems, and more. Method: A human factors experiment was conducted to compare both displays. Eighteen subjects participated in evaluating two simulated interfaces for the leading display and the RSVP display. Results: The results show that the leading display was better in terms of search time and certain subjective measurements (Easiness, frustration, anxiety). The latter results are consistent with the conclusions of other research efforts showing that dynamic displays are more effective and efficient when reading information. Conclusion: The leading display is more useful for Chinese users in terms of both information searching and information reading. Application: This study helps design dynamic displays written in Chinese texts.

• Journal of Communications and Networks
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• 제18권1호
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• pp.84-94
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• 2016

Design of effective cooperative jamming (CJ) algorithm is studied in this paper to maximize the achievable secrecy rate when the total transmit power of the source and multiple trusted terminals is constrained. Recently, the same problem was studied in [1] and an optimal algorithm was proposed involving a one-dimensional exhaustive searching.However, the computational complexity of such exhaustive searching could be very high, which may limit the practical use of the optimal algorithm. We propose an asymptotically optimal algorithm, involving only a fast line searching, which can guarantee to achieve the global optimality when the total transmit power goes to infinity. Numerical results demonstrate that the proposed asymptotically optimal algorithm essentially gives the same performance as the algorithm in [1, (44)] but with much lower computational complexity.

• 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.

• Journal of Electrical Engineering and Technology
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• 제9권3호
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• pp.1023-1033
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• 2014

In this paper, performance improved hole-filling algorithm which includes the boundary noise removing pre-process that can be used for an arbitrary virtual view synthesis has been proposed. Boundary noise occurs due to the boundary mismatch between depth and texture images during the 3D warping process and it usually causes unusual defects in a generated virtual view. Common-hole is impossible to recover by using only a given original view as a reference and most of the conventional algorithms generate unnatural views that include constrained parts of the texture. To remove the boundary noise, we first find occlusion regions and expand these regions to the common-hole region in the synthesized view. Then, we fill the common-hole using the spiral weighted average algorithm and the gradient searching algorithm. The spiral weighted average algorithm keeps the boundary of each object well by using depth information and the gradient searching algorithm preserves the details. We tried to combine strong points of both the spiral weighted average algorithm and the gradient searching algorithm. We also tried to reduce the flickering defect that exists around the filled common-hole region by using a probability mask. The experimental results show that the proposed algorithm performs much better than the conventional algorithms.

• 한국콘텐츠학회논문지
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• 제13권12호
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• pp.136-148
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• 2013

본 연구는 우리나라의 무용단 중 한국무용을 대표할 수 있는 국립무용단, 서울시무용단, 경기도립무용단의 정기공연작품의 주제경향 분석을 통해 무용이 사회와 어떠한 관계를 지녔는지 작품의 주제경향으로 시대별 사회의 흐름을 유추하여 무용과 사회의 구조관계를 조사하고, 무용작품의 주제에 대한 의미를 각인시켜 후속연구에 기반을 제공함에 연구의 목적이 있다. 이 연구의 목적을 수행하기 위하여 선행연구 및 관련서적을 참고한 문헌조사를 중심으로 국립무용단, 서울시무용단, 경기도립무용단 세 무용단으로 선정하여 각 무용단의 창단부터 현재까지의 정기공연을 팜플렛, 신문기사, 무용단의 공연자료 및 관련된 선행논문을 통해 정기공연의 주제를 조사하였다. 자료분석은 주제경향 선행논문에서 공통적으로 사용된 김병석의 분류방법에 따라 무용단의 창단부터 현재까지 공연된 정기공연 내용과 주제를 중심으로 1) 전통의식적 주제, 2) 문학적인 주제, 3) 역사적인 주제, 4) 추상적인 주제, 5) 현실적인 주제, 6) 사회적인 주제로 분류하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 학술대회 논문집 정보 및 제어부문
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• pp.196-199
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• 2004

This paper presents a structure of the searcher using the space diversity in array antenna system operating in the DS/CDMA signal environments. The new technique exploits the fact that the In-phase and Quadrature components of interferers can respectively be viewed as independent Gaussian noise at each antenna element in most practical CDMA (Code Division Multiple Access) signal environments. The proposed PN acquisition scheme is a single dwell serial PN acquisition system consisting of two stage, that is, the searching stage and the verification stage. The searching stage correlates the received signals with the local PN oscilator for obtaining the synchronous energy at the entire uncertainty region. The verification stage compares the searching energy with the optimal threshold, which is pre-designed in the Lock-Detector, and decides whether the acquisition is successful or fail. In this paper, we analyzed the relationship of both diversity order and the mean acquisition time. In general, It is known that the mean acquisition time decreases significantly as the number of antenna elements increases. But, the enhancement of the performance is saturated in terms of PN acquisition scheme. Therefore, to decrease the mean acquisition time, we must design the optimal array antenna system by considering the operating SNR range of the receiver, the detection probability, and the false alarm probability. The performance of the proposed acquisition scheme is analyzed in frequency-selective Rayleigh fading channels. In this paper, the effect of the number of antenna elements on acquisition scheme is considered in terms of the detection probability, false alarm probability. and the mean acquisition time.

• 대한기계학회논문집A
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• 제35권11호
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• pp.1429-1436
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• 2011

본 논문에서는 튜브의 내부에 이물질이 있거나, 조명에 의한 영상잡음이 많은 경우에도 내경중심과 내경을 정확하게 측정할 수 있는 머신비전 기반의 새로운 측정알고리즘을 제안하였다. 또한 내경과 외경 중심간의 이격거리인 편심량도 계산할 수 있다. 제안된 알고리즘은 퍼지제어에 바탕을 둔 반복탐색에 의하여 임의의 초기탐색점에서 거리와 방향을 단계적으로 이동함으로써 내경의 중심에 도달하게 한다. 제안된 알고리즘은 계산시간 뿐만 아니라 측정정밀도 면에도 기존의 방법에 비해 우수하였다. 성능을 비교하기 위하여 생산현장에서 생산되는 튜브들을 이용하여 실험을 수행하였고, 실험 결과 제안된 알고리즘을 사용하는 경우가 널리 사용되고 있는 알고리즘인 Hough 변환 방식과 RANSAC 방식보다 계산시간 및 측정정밀도에서 우수함을 보였다.

• 한국전자파학회논문지
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• 제8권2호
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• pp.116-125
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• 1997

본 논문에서는 신호원의 도착방향을 추정하기 위한 새로운 방안으로 직교가중치 탐색(OWS : Orthogonal Weight Searching)이라고 명명되어진 새로운 기술을 제안한다. 신호공간에 직교하는 가중치 벡터는 개선된 공액기울기 방식(Conjugate Gradient Method)을 이용하여 신호행렬로부터 직접 계산되어진다. 본 논문에서 제안되는 기술은 고유치 및 고유벡터를 구할 필요가 없으며, 어레이 입력신호의 개수가 웨이트의 수보다 크지 않다는 가정하에 신호갯수의 탐지과정을 포함하지 않는다. 제안기술이 탐지절차와는 무관하게 수행되기 때문에 어레이 입력의 개수가 몇개인지 성공적으로 파악할 수 없는 열악한 신호환경하에서 제안기술은 우수한 성능을 나타 낸다. 제안된 기술의 성능은 기존의 잘 알려진 고유분해방법과 신호대 잡음비에 따른 각해상도 변에서 비교되어 지고, 계산상의 복잡도 변에서도 기존의 알고리즘과 비교하여 우수함을 보인다.