• 한국컴퓨터정보학회논문지
• /
• 제22권7호
• /
• pp.47-54
• /
• 2017

Recently, correlation filter based trackers have shown excellent tracking performance and computational efficiency. In order to enhance tracking performance in the correlation filter based tracker, search area which is image patch for finding target must include target. In this paper, two methods to discriminatively represent target in the search area are proposed. Firstly, search area location is estimated using pyramidal Lucas-Kanade algorithm. By estimating search area location before filtering, fast motion target can be included in the search area. Secondly, we investigate multi-channel Local Edge Pattern(LEP) which is insensitive to illumination and noise variation. Qualitative and quantitative experiments are performed with eight dataset, which includes ground truth. In comparison with method without search area estimation, our approach retain tracking for the fast motion target. Additionally, the proposed multi-channel LEP improves discriminative performance compare to existing features.

• 한국방재학회:학술대회논문집
• /
• 한국방재학회 2008년도 정기총회 및 학술발표대회
• /
• pp.711-714
• /
• 2008

The objective of this study is to analyze the relationship between the watershed characteristics and the critical duration of design rainfall. For estimation of critical duration, adjustment Huff's method and ILLUDAS urban runoff model were applied to urban 21 areas. Watershed characteristics such as area, channel length, channel slope, shape factor, and pipe density were used to simulate correlation analysis. The conclusions of this study are as follows; it is revealed that critical duration is influenced by the watershed characteristics such as pipe density, area and channel length. Also, multiple regression analysis using watershed characteristics is carried out and the determination coefficient of multiple regression equation shows 0.972.

• Journal of Communications and Networks
• /
• 제18권1호
• /
• pp.95-104
• /
• 2016

Massive multiple-input multiple-output (MIMO) is a promising approach for cellular communication due to its energy efficiency and high achievable data rate. These advantages, however, can be realized only when channel state information (CSI) is available at the transmitter. Since there are many antennas, CSI is too large to feed back without compression. To compress CSI, prior work has applied compressive sensing (CS) techniques and the fact that CSI can be sparsified. The adopted sparsifying bases fail, however, to reflect the spatial correlation and channel conditions or to be feasible in practice. In this paper, we propose a new sparsifying basis that reflects the long-term characteristics of the channel, and needs no change as long as the spatial correlation model does not change. We propose a new reconstruction algorithm for CS, and also suggest dimensionality reduction as a compression method. To feed back compressed CSI in practice, we propose a new codebook for the compressed channel quantization assuming no other-cell interference. Numerical results confirm that the proposed channel feedback mechanisms show better performance in point-to-point (single-user) and point-to-multi-point (multi-user) scenarios.

• Journal of the Optical Society of Korea
• /
• 제17권6호
• /
• pp.494-499
• /
• 2013

In this paper, we present an optical encryption and information authentication of 3D objects considering wireless channel characteristics. Using the optical encryption such as double random phase encryption (DRPE) and 3D integral imaging, a 3D scene with encryption can be transmitted. However, the wireless channel causes the noise and fading effects of the 3D transmitted encryption data. When the 3D encrypted data is transmitted via wireless channel, the information may be lost or distorted because there are a lot of factors such as channel noise, propagation fading, and so on. Thus, using digital modulation and maximum likelihood (ML) detection, the noise and fading effects are mitigated, and the encrypted data is estimated well at the receiver. In addition, using computational volumetric reconstruction of integral imaging and advanced correlation filters, the noise effects may be remedied and 3D information may be authenticated. To prove our method, we carry out an optical experiment for sensing 3D information and simulation for optical encryption with DRPE and authentication with a nonlinear correlation filter. To the best of our knowledge, this is the first report on optical encryption and information authentication of 3D objects considering the wireless channel characteristics.

• 대한전자공학회논문지TC
• /
• 제42권4호
• /
• pp.15-20
• /
• 2005

일반적으로 공간적 상관도가 존재하는 채널에서 다중 안테나 시스템은 그 성능이 열화되는 것으로 알려져 있다. 이를 극복하기 위한 방안으로 안테나 선택을 통해 공간적 상관도를 극복하고 다이버시티와 공간 다중화의 스위칭을 통해서 시스템의 에러 확률을 개선하는 안테나 선택 및 스위칭 시스템 방식을 들 수 있다. 그러나 이러한 시스템의 경우 채널의 공간적 상관도에 대한 모델링의 어려움으로 인해 이론적인 분석이 미비한 실정이다. 본 논문에서는 채널의 Frobenius norm과 최소 고유치들의 통계적인 특성을 이용하여 안테나 선택 및 스위칭 시스템의 성능을 이론적으로 분석하고, 모의 실험 결과와의 비교를 통해 유사한 성능을 보이고 있음을 확인한다.

• 한국ITS학회 논문지
• /
• 제5권1호
• /
• pp.45-54
• /
• 2006

주파수 선택적 채널에서의 신호왜곡은 수신기에서의 채널추정을 어렵게 하여 펄스 타입의 UWB 시스템의 경우 동기 회로의 구현이 어렵다는 단점이 있다. 본 논문에서는 구현상 난점인 채널추정과 동기회로 설계를 간단히 기준 펄스를 함께 전송함으로써 해결하는 TR(Transmitted Reference), DTR(Differential TR) UWB을 분석하고 FSK 변조방법을 이용한 새로운 형태의 PRM(Pulse Repetition Modulation) UWB 방식을 제안한다. 기준 펄스를 이용한 통신의 수신기 구조인 Auto-correlation(AcR) 수신기가 잡음이 섞인 기준펄스를 이용하는 경우 성능저하 정도를 확률적으로 분석한다. 또한 SNR에 영향을 미치는 AcR 적분기의 적분구간에 대한 분석을 시뮬레이션을 통하여 분석한다.

• 해양환경안전학회지
• /
• 제2권S1호
• /
• pp.63-73
• /
• 1996

The assesment of the safety of ship's transit in a curved narrow channl consists of the maneuvering safety determined by the chance of running aground, the maneuvering difficulty determined by shop's workload, and shiphandler's subjective evaluation. In this study to examine the correlation between shiphandler's subjectice evaluation and the maneuvering risk, the real-time and full-mission shiphandling simulator in the Korean Marine Training & Research Institutes(KMTRI) was utilized. In the conning bridge of the shiphandling simulator, 50 experienced masters conducted masters conducted the modeled vessel of 60,000 deadweight tonnage along the designed channel under 3 different envrinmental conditions. The findings were as follows: (1) The frequencies of stress levels, work difficulties, vessel controllability and overall workload of shiphandlers are similar irrespective of environmental conditions and they are able to be represented as shiphandler's subjective evaluation. (2) It is possible to assess and analyze theoretically the correlation between the shiphandler's subjective ecaluation and maneuvering risk each environmental cindition by quantifying the data obtioned from the tests. The results are as follows: ① As the degree of maneuvering risk increases, the shiphandler's subjective evaluation increases sharply near the curvature area of the desgined channel. ② In the area of the curvature of the designed channel, maneuvering risk increases sharply with the danger of running aground under the environmental condition of current and wind comung from the stem.

• Journal of information and communication convergence engineering
• /
• 제8권2호
• /
• pp.163-167
• /
• 2010

In underwater acoustic communication, acoustic signals from transducers or hydrophones are used. And the underwater acoustic communication channels are very complicated, because of vertical distribution of acoustic velocity according depths, and reflections from boundaries like as surface or bottom. For the implementation of the underwater acoustic communication channel, the image method or ray tracing method have been used. In this paper, we introduce a new approach for implementation of underwater acoustic communication channel using the simulation of the Transmission Line Matrix Modeling and cross-correlations from the input and output signals.

• Journal of Positioning, Navigation, and Timing
• /
• 제4권3호
• /
• pp.97-105
• /
• 2015

A navigation signal based on orthogonal tiered polyphase code was proposed. For the proposed signal, tiered polyphase code was used as the code of a pilot channel. Tiered polyphase code is a complex number type code, and thus the pilot channel and data channel were separated using the Walsh code which makes the correlation between different codes become 0. The results of the simulation indicated that the correlation characteristics and signal acquisition performance of the proposed signal were identical to those of tiered polyphase code, and that the disadvantage of tiered polyphase code could be supplemented through a data channel in terms of signal tracking.

• 전자공학회논문지S
• /
• 제35S권2호
• /
• pp.10-21
• /
• 1998

In this paper, we analyze the anynchrous cellular hybrid DS/FH spread spectrum system with diversity on nonselective Nakagami fading channel. Binary Psk scheme is considered and random spreading code sequences and random hopping patterns are used. We compare the performance of system using hard-limiting correlation receiver with diversity and linear corrleation receiver in Nakagami fading channel. We compute the average bit error probabilities with/without diversity according to spreading code sequence and the number of hop-ping frequencies under the same handwith espansion, and analyze near-far effect. The results show that hard-limiting correlation receiver with diversity gives a good performance over severe fading channel.