• Journal of Institute of Control, Robotics and Systems
• /
• v.16 no.11
• /
• pp.1125-1135
• /
• 2010

A fundamental characteristic of PMHT (Probabilistic Multi-Hypothesis Tracker) is that the number of targets and initial states of targets in the surveillance area must be a priori known. This requirement is impossible to fulfil in almost every realistic scenario. In the paper, we present two track initiation methods to solve the problem. The proposed track initiation methods are 2-point track initiation and Hough transform track initiation, and they are used to evaluate track initial states and weights for FTD (False Track Discrimination) of the PMHT algorithm. Also suggested as automatic target detection for tracking systems that combines track initiation for target detection with the PMHT algorithm for target tracking in a cluttered environment. A series of Monte-Carlo simulation runs is employed to evaluate the overall system performance with the two track initiation methods and the results are compared and analyzed.

• Journal of the Korean Institute of Telematics and Electronics B
• /
• v.30B no.5
• /
• pp.62-72
• /
• 1993

The phased array antenna has the ability to perform adaptive sampling by directing the radar beam without inertia in any direction. The adaptive sampling capability of the phased array antenna allows each sampling time interval to be varied for each target, depending on the acceleration of each target at any time. In this paper we design a three dimensional adaptive target tracking algorithm for the phased array radar system with a given set of measurement parameters. The tracking algorithm avoids taking unnecessarily frequent samples, while keeping the angular prediction error within a fraction of antenna beamwidth so that the probability of detection will not be degraded during a track updata illuminations. In our algorithm, the target model and the sampling rate are selected depending on the target range and the target maneuver status which is determined by a maneuver level detector. A detailed simulation is conducted to test the validity of our tracking algorithm for target trajectories under various conditions of maneuver.

• Proceedings of the Korean Society of Broadcast Engineers Conference
• /
• 2004.11a
• /
• pp.193-196
• /
• 2004

본 논문에서는 열악한 주파수 선택적 페이딩이나 고속 페이딩 채널 환경에서 ATSC(Advanced Television System Committee) DTV 수신기의 등화 성능 향상을 위해 필터 탭을 선택적으로 사용하는 스파스 적응 등화기 구조를 제안한다. 제안된 등화기는 채널 추정을 수행한 후 등화기 초기화를 위한 탭 계수를 찾는다. 구해진 등화기 탭의 초기화 계수에 대해 특정 임계값을 적용하여 유효한 탭을 선택하여 활성화시킨다. 그리고 활성화 된 탭만을 이용하여 채널 등화를 수행한다. 결과적으로 기존 등화기와 동일한 탭 길이를 가지 고 있지만, 실제 사용하는 탭 수가 작아지므로 등화기의 단계상수를 크게 만들어 고속 페이딩 채널의 변화를 빠르게 추적할 수 있게 된다. 제안된 등화기 알고리듬의 성능 개선을 확인하기 위한 실험으로 ATSC DTV 성능분석 시 일반적으로 사용되는 브라질 채널 및 ATSC등화 성능 요구 조건에 대해 기존의 등화기와 비교 분석하였다. 그 결과 기존의 등화기와 같은 안정성을 가지면서 빠른 수렴 속도를 가지고 고속 페이딩 채널 보상 능력의 큰 향상을 보였다.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.43 no.1
• /
• pp.40-48
• /
• 2015

In this paper, we suggest a measurement modeling of the RF seeker using the ISAR(Inverse Synthetic Aperture Radar) image. Reference scattering points are extracted first from ISAR images which are changed according to target attitude. And then uncertainties included in RF seeker measurement such as noise strength, blink, and boresight error are added to the reference scattering points. The proposed measurement model of the RF seeker can be used to develop various kinds of target tracking algorithms.

• Journal of Digital Contents Society
• /
• v.8 no.3
• /
• pp.371-376
• /
• 2007

Many modules such as controller, sensor, telematics terminal, navigation, audio and video are connected each other via vehicle network (CAN, MOST, etc). Futhermore, users can have ITS or internet services in moving by connecting to wireless mobile network. These network capabilities can cause a lots of security issues such as data hacking, privacy violation, location tracking and so on. Some possibilities which raise a breakdown or accident by hacking vehicle operation data (sensor, control data) are on the increase. In this paper, we propose a security module which has encryption functionalities and can be used for vehicle network system such as CAN, MOST, etc. This security module can provide conventional encryption algorithms and digital signature processing functionality such as DES, 3-DES, SEED, ECC, and RSA.

• The Journal of the Acoustical Society of Korea
• /
• v.18 no.6
• /
• pp.9-16
• /
• 1999

As a part of target motion analysis(TMA) with highly noisy bearings-only measurements from a passive sonar system, a nonlinear batch estimator is proposed to provide the initial estimates to a sequential estimator called the modified gain extended Kalman filter(MGEKF). Based on the system observability analysis of passive target tracking, a practical and effective method is suggested to determine the observer maneuvers for improved TMA performance through system observability enhancing. Also suggested is a method to determine observer location for enhanced system observability at the initial phase of TMA from various engagement boundaries which represent the relationship between observer-target relative geometrical data and system observability. The proposed TMA methods are tested by a series of computer simulation runs.

• Journal of the Institute of Convergence Signal Processing
• /
• v.5 no.1
• /
• pp.1-5
• /
• 2004

A new method for the estimation of pitch-frequency contour of voiced speech is presented. The method is based on the double application of Kaiser's energy operator［1］, which has the capabilities of extracting amplitude and frequency of a sinusoidal waveform. According to the modulation model, a vowel can be represented by a combination of damped sinusoids representing formants, modulated by pitch pulses. Therefore, the amplitude envelope of each of the components will give a pitch-like waveform and the pitch can be obtained by averaging the frequencies of this waveform. The first part is the same as Gopalan's approach［9］, but by substituting the LPC based spectral analysis with the second application of energy operator, the algorithm becomes very simple and can be processed on-line. Although the estimation is rather coarse, the suggested algorithm can be useful for getting a general sketch of pitch contour on-line.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.8 no.6
• /
• pp.581-588
• /
• 1997

Time-variant mobile radio fading channels distort amplitude, frequency and phase of a transmitted signal. On channels that have time-variant spectral nulls, the conventional equalizers which have low convergence speed and high sensitiveness to phase distortion yields very poor error rate performance. In this paper, the performance of a combined structure with the data-recycling algorithm and fractionally spaced equalizer (FSE) has been investigated on time-variant mobile radio fading channels through computer simulations and compared to other kinds of equalizers. The results show that the data-recycling FSE has excellent capabilities for tracking rapidly time-variant mobile channels and effective compensation for phase distortion.

• Proceedings of the KSME Conference
• /
• 2008.11b
• /
• pp.2444-2447
• /
• 2008

A new 3D-PTV algorithm (a Volume PTV) based upon a hybrid fitness function has been constructed. A coherency fitness function is introduced using the information of space and time to sort out the correct particle pairs between the two camera images. The measurement system consists of two-high-definition-cameras($1k{\times}1k$), a Nd-Yag laser and a host computer. The developed algorithm has been employed to investigate the flow features of the cylinder wake. The Reynolds numbers with the cylinder diameter (d=10mm) are 360, 720, 900 and 1260. Two-dimensional displacements of the particles of each camera's image and neighbouring constraints were introduced to reduce the calculation loads. More than 10,000 instantaneous 3D vectors have been obtained by the constructed algorithm. The constructed algorithm could recover more than $80{\sim}90%$ of the particle numbers in the image.

• Proceedings of the Korea Water Resources Association Conference
• /
• 1997.05a
• /
• pp.192-198
• /
• 1997

The spatial variation of saturation tendency can be calculated from the Digital Elevation Model (DEM) employing the multiple flow direction algorithm on the platform of Geographic Resources Support Analysis System (GRASS). It is expected that a bettter understanding of dynamical runoff processes in hillslope hydrological scale is obtained through tracing various runoff path such as infiltration excess overland flow component, strutation excess overland flow component and subsurface runoff component. A procedure is suggested to consider the effect of a tile system on calculating the topographic index. A small agricultural subwatershed (3.4 km2) is used for this study.