• Journal of Institute of Control, Robotics and Systems
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• v.18 no.6
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• pp.562-570
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• 2012

This paper proposes a robust object tracking algorithm using object features and on-line learning based particle filter for mobile robots. Mobile robots with a side-view camera have problems as camera jitter, illumination change, object shape variation and occlusion in variety environments. In order to overcome these problems, color histogram and HOG descriptor are fused for efficient representation of an object. Particle filter is used for robust object tracking with on-line learning method IPCA in non-linear environment. The validity of the proposed algorithm is revealed via experiments with DBs acquired in variety environment. The experiments show that the accuracy performance of particle filter using combined color and shape information associated with online learning (92.4 %) is more robust than that of particle filter using only color information (71.1 %) or particle filter using shape and color information without on-line learning (90.3 %).

• The Journal of the Acoustical Society of Korea
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• v.13 no.5
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• pp.15-23
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• 1994

We developed an electronic lens for acoustic imaging systems, which is linear array with 31 microphones equally spaced with distance 34mm. Resonant frequency fo receiver circuit coupled to microphone is 20 kHz. We arranged 16 microphones horizontally and 15 microphones vertically, so that the array allows us to obtain a 2 dimensional angle of source, and to track the motion of source in real time. Due to the problem of aliasing in discrete Fourier Transfrom, the maximum observable angle of the lens is limited to 15${\circ}$. We also employed quadrature phase detection scheme to adjust the focus. We have tested the acoustic lens with a personal computer in an anechoic room and obtained the results agreed with the acoustic imaging theory.

• Journal of Institute of Control, Robotics and Systems
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• v.13 no.7
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• pp.711-717
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• 2007

Location information will become increasingly important for future Pervasive Computing applications. Location tracking system of a moving device can be classified into two types of architectures: an active mobile architecture and a passive mobile architecture. In the former, a mobile device actively transmits signals for estimating distances to listeners. In the latter, a mobile device listens signals from beacons passively. Although the passive architecture such as Cricket location system is inexpensive, easy to set up, and safe, it is less precise than the active one. In this paper, we present a passive location system using Cricket Mote sensors which use RF and ultrasonic signals to estimate distances. In order to improve accuracy of the passive system, the transmission speed of ultrasound was compensated according to air temperature at the moment. Upper and lower bounds of a distance estimation were set up through measuring minimum and maximum distances that ultrasonic signal can reach to. Distance estimations beyond the upper and the lower bounds were filtered off as errors in our scheme. With collecting distance estimation data at various locations and comparing each distance estimation with real distance respectively, we proposed an equation to compensate the deviation at each point. Equations for proposed algorithm were derived to calculate relative coordinates of a moving device. At indoor and outdoor tests, average location error and average location tracking period were 3.5 cm and 0.5 second, respectively, which outperformed Cricket location system of MIT.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.8
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• pp.48-53
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• 2010

5-axis CNC machining now is getting popular because it can deal with complex shapes such as impeller, turbine blade and propeller without additional equipment or process, proving a set of various tool orientations. CAM software related to 5-axis machining is being developed quickly so that users can take advantage of potential capacities of 5-axis machine tools. However, only a few researches can be found in the area of control strategy development for 5-axis machining. This paper proposes a 5-axis cross-coupling control system based on a novel tool orientation error model. The proposed tool orientation error model provides accurate information on the tool orientation error in real time, which in turn enables directly controlling the tool orientation accuracy. The proposed control system also employs a contour error model to calculate the contour error and reflect it in the control as well. The accuracy of the proposed tool orientation error model is verified and the performance of the 5-axis cross-coupling control system in terms of both contouring and tool orientation accuracy is evaluated through computer simulations compared with existing 5-axis control systems.

• IEMEK Journal of Embedded Systems and Applications
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• v.10 no.6
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• pp.363-372
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• 2015

Recent some SoC FPGA Releases that integrate ARM processor and FPGA fabric show better performance compared to the ASIC SoC used in typical embedded image processing system. In this study, using the above advantages, we implement a SoC FPGA-based Real-Time Object Recognition and Tracking System. In our system, the video input and output, image preprocessing process, and background subtraction processing were implemented in FPGA logics. And the object recognition and tracking processes were implemented in ARM processor-based programs. Our system provides the processing performance of 5.3 fps for the SVGA video input. This is about 79 times faster processing power than software approach based on the Nios II Soft-core processor, and about 4 times faster than approach based the HPS processor. Consequently, if the object recognition and tracking system takes a design structure combined with the FPGA logic and HPS processor-based processes of recent SoC FPGA Releases, then the real-time processing is possible because the processing speed is improved than the system that be handled only by the software approach.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.6
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• pp.531-538
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• 2016

In this paper, we design and fabricate a short range FMCW radar which detects and tracks a moving target in a two-dimensional domain using dual transceiver modules. For the short range radar, we propose a scheme for alternate extraction of the two-dimensional positions using one-dimensional range information from time division transceiver modules, and successfully apply the scheme to the two-dimensional short range radar. Measured results of the targets at 10 m and 30 m are presented as performance demonstration of each transceiver module. Also the performance of the two-dimensional radar is demonstrated using a two-dimensional target map, which uses the range bin corresponding to the frequency resolution, and the effectiveness of the proposed scheme is validated.

• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
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• 1991.11a
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• pp.105-133
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• 1991

본 논문에서는 임의의 이진 난수발생기의 source가 $BMS_{p}$ 이거나 M-memory를 갖는 마르코프연쇄로 모델화 되었을 경우에 비트당 entropy와 관련이 있는 새로운 randomness에 관한 통계적 검정법을 제안한다. 기존에 알려진 이진 난수발생기의 randomness검정법이 0또는 1의 분포의 편향성(bias)이나 연속된 비트간의 상관성(correlation)중의 한 종류만의 non-randomness를 추적해낼 수 있는 반면에 새로운 검정법은 위의 두가지 검정을 통과하였을 때 암호학적으로 중요한 측도인 비트당 entropy 를 측정하여 암호학적인 약점을 검정할 수 있다. 또한 대칭(비밀키) 암호시스템의 통계적 결점을 바탕으로 하여 키를 찾는 공격자의 최적 전략( optimal strategy)문제를 분석하여 이 최적 전략이 이진 수열의 비트당 entropy와 밀접한 관계가 있음을 보이고 이 비트당 entropy와 관련이 있는 새로운 통계량을 도입하여 이진 난수 발생기의 source의 이진수열이 다음 3가지 경우, 즉, i.i.d. symmetric인 경우, $BMS_{p}$ 인 경우, M-memory를 갖는 마르코프연쇄인 경우의 각각에 대하여 특성을 조사하고 새로운 통계량의 평균과 분산을 구한다. 이때 구한 새로운 통계량은 잘 알려진 중심 극한 정리에 의하여 근사적으로 정규분포를 따르므로 위의 평균과 분산을 이용하여 스트림 암호시스템에서 구성요소로 많이 사용되는 몇 몇 간단한 이진 난수 발생기에 적용하여 통계적 검정을 실시함으로써 entropy 관점의 검정법이 새로운 randomness 검정법으로 타당함을 보인다.

• Journal of Information Technology Services
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• v.6 no.3
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• pp.241-249
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• 2007

This paper describes a real-time face tracking system using effective detector and Kalman filter. In the proposed system, an image is separated into a background and an object using a real-time updated face color for effective face detection. The face features are extracted using the five types of simple Haar-like features. The extracted features are reinterpreted using Principal Component Analysis (PCA), and interpreted principal components are used for Support Vector Machine (SVM) that classifies the faces and non-faces. The moving face is traced with Kalman filter, which uses the static information of the detected faces and the dynamic information of changes between previous and current frames. The proposed system sets up an initial skin color and updates a region of a skin color through a moving skin color in a real time. It is possible to remove a background which has a similar color with a skin through updating a skin color in a real time. Also, as reducing a potential-face region using a skin color, the performance is increased up to 50% when comparing to the case of extracting features from a whole region.

• The Transactions of the Korea Information Processing Society
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• v.5 no.5
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• pp.1204-1215
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• 1998

In this paper, we propose a scenario representing method, a specification language, and a verification technique for OARTS(Object based Approach for Real-Time Systems). As well as the general modeling method(event trace diagram), this study includes a specification language and a verification technique because there was no study about methodological level technique for scenario development as yet. Centering around the synchronization problem of transition of external modules which are the communication interfaces based on the objects, we lay stress on the representation of sequence of external events and internal action transitions. From the results of practical experiences, it has been ascertained that the proposed method reflect well the requirements in the analysis step, and its validity of the representation has been identified by a conceptual verifier. We support that it can serve as an analyzing tool for representing a general real-time scenarios also.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.12
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• pp.1942-1949
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• 2016

This paper proposed automatic path-tracing methods for Flying Disc Golf by adopting IoT comcepts at smart-marker. We tried to implement service system by making database. Smart-marker's configurations & roles are proposed. By making test-boards and adoption to various Flying Disc Golf games, the efficiency is proved. The positions and distances captured by the smart-marker are transferred to the smart-pole per each hole. The smart-pole captured them and transfers to web-server which is databased them. The result can be searched by web or smartphone in real time.