• Title/Summary/Keyword: Digital Duplex

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A real-time acoustic echo canceller implemented on the multimedia PC (멀티미디어 PC상에 구현된 실시간 음향 반향제거기)

  • Cha, Youn-Cheul;Yoo, Jae-Ha;Youn, Dae-Hee
    • Journal of the Korean Institute of Telematics and Electronics S
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    • v.35S no.11
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    • pp.184-193
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    • 1998
  • In this paper, a real-time acoustic echo canceller is implemented using only PC's CPU without extra help from a DSP chip. The adaptive digital filter is designed efficiently so that it can be implemented in real-time and has a proper cancellation performance. It is proposed that a new double talk detector consumes a small computational complexity and guarantees the fast detection and robust operation. The real-time acoustic echo canceller consists of the full-duplex sound card and 166 MHz Pentium PC, and requires less than 10% CPU time.

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Remote Measurement for Automobile′s ECU Diagnostic Signals based on the PDA (PDA 기반의 차량 진단신호의 원격 계측)

  • 윤여흥;서지원;이현호;권대규;이영춘
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2002.05a
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    • pp.279-282
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    • 2002
  • In this paper, we present a new method for monitoring of ECU's self diagnostic signals of vehicle without wire. In order to measure the ECU's self diagnostic signals, the interfaced circuit is designed to communicate ECU and a designed display terminal according to the ISO, SAE regulation of communication protocol standard. A 80C196KC processor is used for communicating ECU's self diagnostic signals and the results are sent to PDA monitoring system. Software on PDA is developed to monitor the ECU's self diagnostic signals using the Embedded Visual C++ compiler in which RS232 port is programmed by half duplex method. The algorithms for measuring the ECU's self diagnostic signals are verified to monitor ECU's state. At the same time, the information to fix the vehicle's problem can be shown on the developed PDA software. The possibility for remote measurement of ECU self diagnostic signal using PDA is also verified through the developed systems and algorithms.

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A Case Report of Posttraumatic Pseudoaneurysm of the Superficial Temporal Artery (외상 후 발생한 얕은관자동맥 가성동맥류의 치험례)

  • Kim, Nam Hun;Yang, Jeong Yeol;Cheon, Ji Seon;Kim, Gyu Bo
    • Archives of Craniofacial Surgery
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    • v.11 no.1
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    • pp.49-52
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    • 2010
  • Posttraumatic pseudoaneurysm of the superficial temporal artery is very rare and occurs secondary to trauma. Clinical diagnosis is based on past history of trauma and physical examination and can be confirmed by duplex ultrasonogram, digital subtraction angiography, CT and MRI. Ligation of proximal and distal ends of the superficial temporal artery and excision of the pseudoaneurysm has been the standard treatment. Compressive therapy, endovascular coil embolization, percutaneous thrombin injection under ultrasound guidance have been reported as alternative treatment methods. When surgical excision of the superficial temporal artery pseudoaneurysm is performed, surgeon must be concerned about the anatomical relation between superficial temporal artery and temporal branches of the facial nerve. In this article, we report a rare case of superficial temporal artery pseudoaneurysm with some review of the literatures about anatomical relation between superficial temporal artery and temporal branches of facial nerve.

Equipment Qualification of Control Rod Control System for Nuclear Power Plants (원전용 제어봉 제어시스템의 기기검증)

  • Lee, J.M.;Kim, C.K.;Cheon, J.M.;Park, M.K.;Kweon, S.M.;Nam, J.H.
    • Proceedings of the KIEE Conference
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    • 2005.07d
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    • pp.2603-2605
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    • 2005
  • This paper describes an experience on the equipment qualification of CRCS(control rod control system) that has been developed for nuclear power plants. A very high level criteria should be satisfied for the equipment to be used for nuclear power plants. We have developed a CRCS that is aimed to be applied to commercial plants. This system adopts a duplex system structure that is based on the state-of-the-art digital technology so that it has higher reliability than the existing systems. The CRCS has been tested at a licensed testing organization and finally qualified. In this paper, the procedures and some trial-and-errors we have been through in the qualification process are explained. It is expected that our experience will be a helpful tips to the industry that are developing various systems for safety-critical plants.

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A Study on the Design of Echo-Canceller using SIA(Stochastic Iteration Algorithm) (SIA(Stochastic Iteration Algorithm)을 이용한 반향제거기 설계에 관한 연구)

  • Cho, Hyon-Mook;Kim, Sang-Hoon;Park, Nho-Kyung;Moon, Dai-Tchul;Tchah, Kyun-Hyon
    • The Journal of the Acoustical Society of Korea
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    • v.13 no.2
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    • pp.38-49
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    • 1994
  • This paper proposes Echo canceller used in simultaneous two-way ('full-duplex') transmission of data signals over two-wire circuits which can be achieved by using a hybrid coupler. This Echo canceller uses sequential processing instead of parallel processing with conventional adaptive digital filter. This structure reduces the number of multipliers. Thus, this structure is much more suitable for IC implementation. This Echo canceller operates according to the 'Stochastic Iteration Algorithm(SIA).' SIA algorithm has merit of good performance and small hardware requirement.

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A Digital Right Management System based on Shared Key fool for Video Data Protection (동영상 데이터 보호를 위한 공유 키 풀 기반의 DRM 시스템)

  • Kim Jung-Jae;Park Jae-Pyo;Jun Moon-Seog
    • The KIPS Transactions:PartC
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    • v.12C no.2 s.98
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    • pp.183-190
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    • 2005
  • In this thesis, first, we propose I-frame encryption techniques of video data for video data itself encryption and propose license agent that processing user's certification and decryption in client system automatically when user execute encrypted video data in system server. License agent runs user's certification, encryption and decryption of video data based on PID(Public Key Infrastructure) using shared key-pool when execute of video data. Also, compose duplex buffer control and propose real time decryption method using efficient buffer scheduling to reduce much playing delay times that happen processing decryption when execute of videoa data of high-capacity.

A Study of Image Characteristics due to Focus-Grid and Head Phantom Decentering from the Armorphos Silicon Thin Film Transistor Detector the Fixed Focus-Grid is Applied (고정식 초점형 격자가 적용된 비정절 실리콘 평판형 검출기에서 초점-격자와 두부 팬텀의 중심 변위에 의한 화질 특성에 관한 연구)

  • Choi, Jun-Gu;Kim, Byeong-Gi;Cha, Seon-Hwa;Kim, Gyeong-Su
    • Korean Journal of Digital Imaging in Medicine
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    • v.9 no.1
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    • pp.7-15
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    • 2007
  • This study aim to investigate image characteristics due to focus-grid and head phantom decentering from the armorphos silicon thin film transistor detector the fixed focus-grid is applied, wish to propose right use method of digital medical equipment. Acquired image according to focus-grid and head phantom position decentering using head phantom on armorphos silicon thin film transistor detector the fixed focus-grid is applied. acquired image evaluate pixel value, histogram, plot profile, surface plot using NIB (Image J) image analysis program and compared decentering image with standard image. Mean value and standard deviation value of focus-grid lateral decentering and duplex decentering of focus-grid and head phantom decreased by ratio, consequently increase of horizontality, diagonal decentering. also, deteriorated contrast of image because frequency of high pixel value decreases fairly. according increases decentering, image distortion phenomenon was increase, by next time, pixel mean value of head phantom decentering was no big change but horizontality, diagonal, mean value and standard deviation value of pixel decreased by ratio. Even if increase pixel noise of image because wide latitude and post processing ability of digital detector, radiotechnologist can not recognize. Therefore, radiotechnologist must recognize correctly the photographing factors which increases pixel noise on the grid system installation digital detector and should exam.

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FEXT cancellation for high-speed local transmission over twisted pair wiring (동축 선로에서의 초고속 근거리 전송을 위한 FEXT 제거기)

  • 우정수;강규민;임기홍
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.27 no.8C
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    • pp.782-791
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    • 2002
  • This paper discusses a far-end crosstalk (FEXT) canceller for twisted-pair transmission. Many twisted-pair systems such as fiber-to-the-curb (FTTC), very high-speed digital subscriber line (VDSL), and high-speed LAN systems, use frequency-division duplexing (FDD) for duplex transmission. It is shown that the maximum reach of FDD twisted-pair system is limited by the performance of its upstream channel, which is located at higher frequencies than the downstream channel. In order to improve the performance of such FDD transceiver, FEXT cancellation is introduced for the channel at higher frequencies. A system arrangement and its blind start-up procedure are studied when the FEXT canceller and equalizer are jointly adapted to combat channel intersymbol interference (ISI), FEXT, and other additive noise. The initial convergence and the steady-state behavior of the proposed twisted-pair system without requiring transmission of an ideal training sequence are investigated. Measured characteristics as well as analytical model of the FEXT channel are used to estimate the time span needed for the FEXT canceller. It is also shown that the memory span for the FEXT canceller is almost independent of the channel, thus making our results useful for the twisted-pair system over all different channels.

Design and Implementation of Content Management System for Improvement of Compatibility and Publication (호환성 및 상호운용성이 개선된 콘텐츠관리시스템의 설계 및 구현)

  • Min, Byung-Won
    • Journal of Digital Convergence
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    • v.12 no.2
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    • pp.257-262
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    • 2014
  • Although the amount of UCC(user created content) rapidly grows nowadays, there are various problems in authoring, distribution and management of this abundant content because the platforms for fabrication and replaying content are not compatible and the authoring environments are not sufficiently interoperable with other site or with each other. In this paper, we propose a CMS(content management system) scheme improved in interoperability to solve these problems, and we design a novel system enhancing the efficiency and speed of content distribution and management by minimizing the repetitions in the processes of production, reshaping, and publication. Moreover the proposed system adopts an improved content management technology by changing from simple point-to-point method to the centralized distribution method, and as for the service scheme, we change from the site link method to the database link method, and we also take duplex interlink scheme instead of simplex one. We finally compare the proposed system to the conventional ones as points of view of compatibility and interoperability to prove the improved performance of our system.

Implementation of a G,723.1 Annex A Using a High Performance DSP (고성능 DSP를 이용한 G.723.1 Annex A 구현)

  • 최용수;강태익
    • The Journal of the Acoustical Society of Korea
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    • v.21 no.7
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    • pp.648-655
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    • 2002
  • This paper describes implementation of a multi-channel G.723.1 Annex A (G.723.1A) focused on code optimization using a high performance general purpose Digital Signal Processor (DSP), To implement a multi-channel G.723.1A functional complexities of the ITU-T G.723.1A fixed-point C-code are measures an analyzed. Then we sort and optimize C functions in complexity order. In parallel with optimization, we verify the bit-exactness of the optimized code using the ITU-T test vectors. Using only internal memory, the optimized code can perform full-duplex 17 channel processing. In addition, we further increase the number of available channels per DSP into 22 using fast codebook search algorithms, referred to as bit -compatible optimization.