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

• Korean Journal of Optics and Photonics
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• v.18 no.6
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• pp.410-420
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• 2007

We theoretically derive the set of utilizable paraxial zoom locus equations for all complicated zoom lens systems with infinite object distance, such as a camera zoom lens, by using the Gaussian bracket method and the matrix representation of paraxial ray tracing. And we make the zoom locus program according to these equations in Visual Basic. Since we have applied the paraxial ray tracing equations into Gaussian bracket representation, the resultant program systematically simplifies various constraints of the zoom loci of various N group types. Consequently, the solutions of this method can be consistently used in all types of zoom lens in the step of initial design about zoom loci. Finally, in order to verify the usefulness of this method, we show that one example among 4 groups and that among 5 groups, which are very complex zoom lens systems, can be rapidly and with versatility traced through various interpolations by using this program.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.5
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• pp.275-280
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• 2013

In this paper, a new stereo object extraction algorithm using a block-based MSE (mean square error) algorithm and the configuration parameters of a stereo camera is proposed. That is, by applying the SSD algorithm between the initial reference image and the next stereo input image, location coordinates of a target object in the right and left images are acquired and then with these values, the pan/tilt system is controlled. And using the moving angle of this pan/tilt system and the configulation parameters of the stereo camera system, the mask window size of a target object is adaptively determined. The newly segmented target image is used as a reference image in the next stage and it is automatically updated in the course of target tracking basing on the same procedure. Meanwhile, a target object is under tracking through continuously controlling the convergence and FOV by using the sequentiall extracted location coordinates of a moving target.

• The KIPS Transactions:PartB
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• v.11B no.1
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• pp.27-34
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• 2004

This paper proposes a method to trace and interpret a moving object based on the information which can be directly obtained from MPEG-2 compressed video stream without decoding process. In the proposed method, the motion flow is constructed from the motion vectors included in compressed video. We calculate the amount of pan, tilt, and zoom associated with camera operations using generalized Hough transform. The local object motion can be extracted from the motion flow after the compensation with the parameters related to the global camera motion. Initially, a moving object to be traced is designated by user via bounding box. After then automatic tracking Is performed based on the accumulated motion flows according to the area contributions. Also, in order to reduce the cumulative tracking error, the object area is reshaped in the first I-frame of a GOP by matching the DCT coefficients. The proposed method can improve the computation speed because the information can be directly obtained from the MPEG-2 compressed video, but the object boundary is limited by macro-blocks rather than pixels. Also, the proposed method is proper for approximate object tracking rather than accurate tracing of an object because of limited information available in the compressed video data.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.13 no.2
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• pp.161-171
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• 1993

The basin instantaneous unit hydrograph was derived by considering the network geometry and hillslope. The network geometry is quantified in a function, termed the width function, that reflects the distribution of runoff with flow distance from the outlet. The model using the derivation of the basin IUH consists of two components: the routing component of the initial distribution through the network by means of a simplified diffusion approximation and the hillslope component by means of a exponential distribution that is the probability density function of the travel time in the hillslope. The application of this method was tested on four observed flood data of Bocheong stream and Wi stream. The results show that the proposed method can be used for the analysis of the basin IUH.

• Journal of the Korean Institute of Telematics and Electronics
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• v.20 no.4
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• pp.55-60
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• 1983

A new type of digital phase-locked loop (DPLL) that employs a multilevel quantified timing error detector (TED) is proposed and analyzed under the assumption of negligible quantizing effect and no noise. Since the timing error is quantized uniformly, the TED has a linear characteristic. From the linear characteristic of TED, a first order difference equation describing the behavior of the loop is derived. Using the system equation, the loop is analyzed mathematically for phase step and frequency step input. Desired locking condition for the loop to be locked and the lock range for the DPLL's to achieve exact locking independently of initial conditions are ob-tained. And these analyses are confirmed by timing error plane plots and computer simulation.

• Journal of Broadcast Engineering
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• v.11 no.1 s.30
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• pp.80-90
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• 2006

A simple 2D gaze tracking method using single camera and Purkinje image is proposed. This method employs single camera with infrared filter to capture one eye and two infrared light sources to make reflection points for estimating corresponding gaze point on the screen from user's eyes. Single camera, infrared light sources and user's head can be slightly moved. Thus, it renders simple and flexible system without using any inconvenient fixed equipments or assuming fixed head. The system also includes a simple and accurate personal calibration procedure. Before using the system, each user only has to stare at two target points for a few seconds so that the system can initiate user's individual factors of estimating algorithm. The proposed system has been developed to work in real-time providing over 10 frames per second with XGA $(1024{\times}768)$ resolution. The test results of nine objects of three subjects show that the system is achieving an average estimation error less than I degree.

• The KIPS Transactions:PartB
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• v.14B no.7
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• pp.493-502
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• 2007

An on-line registration technique is presented to register multi-view range images for the 3D reconstruction of real objects. Using a range camera, we first acquire range images and photometric images continuously. In the range images, we divide object and background regions using a predefined threshold value. For the coarse registration of the range images, the centroid of the images are used. After refining the registration of range images using a projection-based technique, we use a modified KLT(Kanade-Lucas-Tomasi) tracker to match photometric features in the object images. Using the modified KLT tracker, we can track image features fast and accurately. If a range image fails to register, we acquire new range images and try to register them continuously until the registration process resumes. After enough range images are registered, they are integrated into a 3D model in offline step. Experimental results and error analysis show that the proposed method can be used to reconstruct 3D model very fast and accurately.

• KDI북한경제리뷰
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• v.21 no.10
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• pp.29-72
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• 2019

본 연구는 김정은 집권 이후 북한 농업부문에서 계획과 시장의 공존 양태를 분석하는 것을 목적으로 한다. 북한 협동농장의 계획 수행 과정을 계획수립-계획실행-계획평가 단계로 나누어 추적한 결과, 협동농장에 대한 계획화체계의 골격은 상대적으로 강하게 유지하고 있다. 계획수립과 계획평가 단계에서는 명령식 계획경제의 틀을 고수하고 있다. 그러나 계획실행 즉 자금·자재·노동력 등 생산요소 확보-생산-생산물 처분 단계에서는 당국 및 상급기관의 사실상 방임 하에 협동농장이 적극적인 시장과의 연계를 통해 자력으로 일을 추진하고 있다. 농업부문의 계획 밖 영역, 즉 시장에서의 변화실태를 파악한 결과, 농업관련 제반 시장들이 새롭게 만들어져 성장하고 있다. 농산물 소비재시장(곡물시장, 채소시장, 축산물시장, 과일시장), 농업 및 비농업 생산재시장(영농자재시장, 식품원료 및 식자재시장)이 생겼으며 점차커지고 있다. 도시의 구매력 향상에 따라 다양한 먹을거리에 대한 수요가 증가하면서 자가소비를 목적으로 생산하던 농산물을 남에게 팔기 위한 '상품'으로 인식함으로써 수요를 겨냥한 공급 확대 등 중요한 변화가 나타났다. 농촌의 구매력도 커지면서 영농자재 시장의 수요와 공급이 늘어났다. 이는 시장화에 일시적으로 후행하던 농촌이 도시 수요를 겨냥한 농업생산에 본격적으로 나서게 됨으로써 시장경제적 질서에 재편입하고, 시장연계활동의 많고 적음에 따라 농촌간 격차가 나타나는 등 북한 농업부문이 개발도상국 경제에서 출현하는 농업근대화의 초기 양상과 일부 유사함을 말해준다.

• The Journal of Society for e-Business Studies
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• v.12 no.3
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• pp.33-47
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• 2007

The requirements have been changed during development progresses, since it is impossible to define all of software requirements. These requirements change leads to mistakes because the developers cannot completely understand the software's structure and behavior, or they cannot discover all parts affected by a change. Requirement changes have to be managed and assessed to ensure that they are feasible, make economic sense and contribute to the business needs of the customer organization. We propose a feature-oriented requirements change management method to manage requirements change with value analysis and feature-oriented traceability links including intermediate catalysis using features. Our approach offers two contributions to the study of requirements change: (1) We define requirements change tree to make user requirements change request generalize by feature level. (2) We provide overall process such as change request normalization, change impact analysis, solution dealing with change request, change request implementation, change request evaluation. In addition, we especially present the results of a case study which is carried out in asset management portal system in details.