• The Transactions of the Korean Institute of Electrical Engineers
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• v.35 no.6
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• pp.209-216
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• 1986

This paper describes the design of multi channel data acquisiton system for industrial process automation. The prototype hardware assembly consists of Z-80A microprocessor, 10-bit A/D converter with 16-channel analog multiplexor and related interface circuitry. The first order lag filter, which can be implemented without any particular computational problem has implemented in software, and the simulation results are shown. The protype system can communicate with a central processor through RS-232C, and can be used either as an intelligent stand-alone controller or as a satellite controller which can be monitored and controlled by a central processor. The singal conditioners for various temperature and humidity sensors are designed and experimental results are shown.

• The Journal of the Acoustical Society of Korea
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• v.17 no.4E
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• pp.17-21
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• 1998

This paper presents an implementation of a multi-channel speech surveillance system over telephone lines using TMS320C31 DSP chips. The incoming speech into each telephone line are first compressed simultaneously in real-time by the popular vector-sum excited linear predictive (VSELP) speech coding algorithm at the rate of 8 Kbps. The compressed steech bit streams are then multiplexed with those of other users. The multiplexed speech bit streams are transferred to the system storage equipments with some other required information so that a system operator can later monitor the stored speech data whenever it is necessary. The host program runs under Microsoft Windows95 for an efficient man-machine interface and a future upgrade-ability. We have confirmed that the overall 64-channel system operates satisfactorily in realtime. We also have checked approximately up to 2,880 total hours of recording capability of the system on a playback module and two removable backup drives.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.8
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• pp.2033-2042
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• 1996

In this papre, we describe a recently implemented echo canceller for digital cellular communication of Code Division Multiple Access(CDMA) that features time sharing of digital signal processor(DSP) over four channels in one DSP to reduce per channel costs. In the Public Land Mobile Network(PLMN), it is important to cancel the echo reflected from the Public Switched Telephone Network(PSTN) side. In case of digital mobile system, the round-trip delay of the echo is in excess of about 180 milliseconds due to frame-by-frame voice coding. It is necessary to cancel the echo in PLMN. We have developed a multi-channel echo canceller tht operates with Time Switch Module in a Mobile Switching Center(MSC). The general echo canceller needs PCM trunk interface circuits and the tone detection and disabling circuits, but the multi-channel echo canceller linked with Time Switch Module does not need them. Therefore we could develop the effective and economical echo canceller.

• Journal of Advanced Navigation Technology
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• v.6 no.4
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• pp.306-311
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• 2002

In this paper, we have proposed the Multi-Carrier (MC) CDMA system by adopting multi-interference cancellation techniques connecting an adaptive array antenna and a CCI canceller in cascade form. And, we have analyzed the BER performance of system in AWGN channel where MUI is a major interference degrading the performance of the proposed MC CDMA system. Also, we have evaluated the degree of performance improvement in the proposed MC CDMA system. As the result of analysis, a CCI canceller is better efficient than an adaptive array antenna in the performance improvement and that the performance improvement becomes large as the number of users increases when multi-interference cancellation techniques are used in cascade form. Also, we found that performance of $10^{-5}$ in a point of view BER could be achieved when $E_b/N_o$ is more than 10 dB.

• 한국IT서비스학회:학술대회논문집
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• 2010.05a
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• pp.202-206
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• 2010

무선 메쉬 네트워크(Wireless Mesh Network, WMN)는 유비쿼터스 환경 및 무선 브로드 밴드 액세스를 제공하기 위한 차세대 핵심기술로 떠오르고 있다. 다양한 멀티미디어 서비스가 존재하는 유비쿼터스 환경에서 실시간 서비스 제공을 위해서는 네트워크 용량 증대가 요구되며, 이를 위하여 WMN에서 네트워크 용량을 증대시키기 위한 다중 인터페이스 활용 기술이 중요한 이슈로 대두되고 있다. 하지만 WMN에서 주로 사용하는 인터페이스 기술인 IEEE 802.11 표준에서는 IEEE 802.11b/g 또는 IEEE 802.11a와 같은 스펙에 따라 간섭 없이 사용할 수 있는 채널은 3개 또는 12개로 한정되어 있기 때문에 다중 인터페이스 활용을 통해 증대된 가용 자원 효율성을 극대화하기 위해서 효율적인 채널 할당 기법의 연구가 요구되며, 이에 따라 본 논문에서는 채널 그룹 설정을 통하여 간섭 발생을 최소화하며 채널스캐닝 과정을 수행하지 않고 채널 변경을 진행함으로써 채널 스캐닝 과정으로 발생하는 전송 지연을 최소화하여 네트워크 성능을 향상시킬 수 있는 채널 할당 기법을 제안한다.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.62 no.4
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• pp.164-168
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• 2013

Recently, in the elevator of the buildings, such as apartment and office building, the visitor monitoring cameras for surveillance, advertising LCD to provide a variety of information, emergency call devices, and safe driving information sensors are installed. A variety of multimedia data from these devices to the central control office, management office, or to guard room are transmitted in real-time. Each sub-systems in the elevator are installed with a separate lines and operated independently and use different management principals, so integrated management for each sub-systems are very difficult. In this study, we develop a new IP-based multi-channel video surveillance system which is integrated surveillance camera, emergency call devices, communications devices, various sensors in the elevator, DVR, ODM, and can manage all devices by two-way communication and integrated interface. And we evaluated the performance of the developed system.

• Proceedings of the KSRS Conference
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• 2004.10a
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• pp.601-603
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• 2004

Multi-Spectral Camera(MSC) is a payload on the KOMPSAT -2 satellite to perform the earth remote sensing. The instrument images the earth using a push-broom motion with a swath width of 15 km and a ground sample distance (GSD) of 1 m over the entire field of view (FOV) at altitude 685 Km. The instrument is designed to have an on-orbit operation duty cycle of $20\%$ over the mission lifetime of 3 years with the functions of programmable gain! offset and onboard image data compression/storage. MSC instrument has one(1) channel for panchromatic Imaging and four(4) channel for multi-spectral Imaging covering the spectral range from 450nm to 900nm using TDI CCD Focal Plane Array (FPA). In this paper, the configuration, the interface of MSC hardware and the MSC operation concept are described. And the method of the MSC calibration are described and the design of MSC calibration operation to measure the change of MSC after Launch & Early Operation(LEOP) and normal mission operations are discussed and analyzed.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.825-827
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• 2003

Multi-Spectral Camera(MSC) is a payload on the KOMPSAT-2 satellite to perform the earth remote sensing. The instrument images the earth using a push-broom motion with a swath width of 15 km and a ground sample distance (GSD) of 1 m over the entire field of view (FOV) at altitude 685 Km. The instrument is designed to have an on-orbit operation duty cycle of 20% over the mission lifetime of 3 years with the functions of programmable gain/ offset and on-board image data compression/storage. The MSC instrument has one(1) channel for panchromatic imaging and four(4) channel for multi-spectral imaging covering the spectral range from 450nm to 900nm using TDI CCD Focal Plane Array (FPA). In this paper, the architecture and function of MSC hardware including electrical interface and the operation concept which have been established based on the mission requirements are described. And the design and the preparation of MSC system operation are analyzed and discussed.

• The Journal of the Korea institute of electronic communication sciences
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• v.8 no.1
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• pp.199-206
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• 2013

Recently, the diverse needs of the drivers for in-vehicle infotainment systems are increasing rapidly. As a result, the infotainment systems are equipped with more convenient and human-friendly high-tech features. In this paper, we designed and implemented in-vehicle multimedia infotainment system based on embedded system that was applied various multimedia to in-vehicles. The proposed system can support independent display on each screen for the multi-channel multimedia source based on one processor(1 CPU). Therefore, our system can be reduced costs compared to other systems. This system not only displays the video and audio data in storage devices but also displays CAM, T-DMB, and DVB-T multimedia contents which are supplied in real-time services. Also, our system could multi-screen displays multimedia data in smart phone using Wi-Fi. We expect that in-vehicle infotainment systems like AVN(Audio video navigation) and RSE(Rear Seat Entertainment) could be used in various applications and reduced costs.

• The KIPS Transactions:PartA
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• v.9A no.4
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• pp.451-458
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• 2002

In this article, we present, design, and implement a software and hardware for an embedded RAID system. The merits and drawbacks of our system are presented by performance evaluation. The proposed hardware system consists of three fibre channel controllers for the interface with fibre channel disks and hosts. Embedded Linux in which a RAID software is implemented is ported to the hardware. A SCSI target mode device driver and a target mode SCSI module are designed for that our RAID system is considered as a block device to a host computer. Linux Multi-device is used as RAID functions of this system. A data cache module is implemented for high performance and the interconnection between Linux Multi-device and the target mode SCSI module. The RAID 5 module of Multi-device is modified for improvement of read performance. The benchmark shows that the new RAID 5 module is superior to the original one in overall performance.