• Journal of Korea Multimedia Society
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• v.24 no.1
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• pp.95-105
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• 2021

In the case of laptops and tablet PC's that replace desktop, it uses the Windows operating system to provide various functions depending on operating system dependency, the Windows operating system does not support real-time processing because it uses multi-level feedback queue scheduling that extends round-robin scheduling. Also, since the initial value of Local APIC Counter can not be obtained from the Windows 8, the real-time processing function provided through the existing RTiK does not work. In this paper, we calculate Local APIC Counter value by using MSR_FSB_FREQ register to support real-time processing function on tablet PC's. We designed and implemented RTiK+, which provides real-time processing function to guarantee the periodicity by calculating the operation time of accurate timer. In order to verify and evaluate the performance of the implemented the RTiK+, the period was measured by using the Read Time-Stamp Counter(RDTSC) instruction and it was confirmed that it operates normally at 1ms and 0.1ms period.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.9
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• pp.1259-1265
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• 2014

In this paper, the real-time attitude determination based Matlab using low-cost receivers was designed and evaluated. The GNSS attitude determination system was implemented to operation in real-time by TimerCallback in MATLAB. The TTM(Transmission Time Misalignment) of U-blox receiver was confirmed through zero baseline tests and this problem was revised. The computed attitude by the high-cost NovAtel receiver was compared to the computed attitude by the low-cost U-blox receiver. As a result of this, the performance of attitude determination systems by low-cost receiver was confirmed. To determine baseline, LAMBDA and BC-LAMBDA for integer ambiguities search methods were used. To confirm suitable integer ambiguity search method in real-time attitude determination algorithm, determined baselines by two methods were compared, and it was confirmed that BC-LAMBDA is more suitable. As a result of this, the operation of real-time attitude determination system was confirmed using 3 low-cost receivers.

• Proceedings of the Korea Contents Association Conference
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• 2011.05a
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• pp.21-22
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• 2011

의료 기기, 항공 제어, 군 장비 등에서 쓰이는 임베디드 시스템은 특정한 목적만을 수행하기 위해 따로 설계된 시스템을 말한다. 이러한 임베디드 시스템에서는 정확한 시간을 예측하여 정해진 시간 안에 처리하기 위한 실시간성이 제공되어야 한다. 리눅스는 다수의 사용자가 이용하는 안정되고 검증된 운영체제로서 임베디드 시스템에서 많이 사용되며, 실시간성을 제공하기 위해 RTAI, RT-Linux를 이용한다. 하지만 RTAI는 Hard Real-time을 제공하지 못하는 문제점을 가지고 있고, RT-Linux의 경우 Hard Real-time은 제공하지만 많은 어셈 코드를 수정해야 하기 때문에 개발의 어려움이 있다. 또한 리눅스 커널에 실시간적 요소를 직접 추가하는 방법도 있지만 커널 코드를 수정할 때 마다 커널 컴파일을 해줘야 하는 문제점이 있다. 이에 따라 리눅스 상에서 실시간성을 제공해 주면서, 개발의 편의성을 제공 할 수 있는 방법이 필요하다. 본 논문에서는 실시간성을 제공하기 위한 타이머 핸들러 부분을 커널 코드로부터 분리하여 실시간성을 제공 해주며, 개발의 편의성을 제공할 수 있는 방법을 설계 및 구현하였다.

• Proceedings of the KWS Conference
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• 2000.04a
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• pp.303-306
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• 2000

Quality estimation of the weld has been one of the important issues in RSW which is a main process of the sheep metal fabrication in auto-body industry, It was well known that among the various welding process variables, dynamic resistance has a close relation with nugget formation. With this variable, it is possible to estimate the weld quality in real time. In this study, a new quality estimation algorithm is developed with the primary dynamic resistance measured at welding machine timer. For this, feature recognition method of Hopfield neural network is used. Primary resistance patterns are vectorized and classified with five patterns. The network trained by these patterns recognizes the dynamic resistance pattern and estimates the weld quality Because the process variable monitored at the primary circuit is used, it is possible to apply this system to real time application without any consideration of electrode wear or shunt effect.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.229-232
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• 2000

This research aims at developing a low-cost PC-NC system based on one-CPU and investigating the feasibility of its application to a simple-function lathe. Its hardware consists a two axes motion control board including a 24bit counter, 8253 timer, a 12bit DA converter, DIO board for PLC operation and a PC with Intel Pentium 466MHz. The fundamental real-time MC functions such as G-code interpretation, interpolation, position and velocity control of axes are performed. User programming interface with functions of icon manipulation, tool-path simulation and NC-code generation was implemented. In order to achieve real-time control and safety, axis control, NC interpretation, interpolation and user communication are completely executed during every interrupt interval of I msec.

• Proceedings of the Korean Information Science Society Conference
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• 2002.04a
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• pp.373-375
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• 2002

리눅스 컴퓨터 시스템에 실시간 웅용프로그램들을 실행할 경우, 실시간 응용프로그램 자체의 내부나 하부에 실시간 시스템 지원을 위한 엔진을 내장하고 있어야 만다. 그러나 기존의 리눅스 시스템들에 실시간 웅용프로그램을 적용하기 위만 실시간성을 보장 받기 위해서는 스케줄러의 실시간성 빈약 등으로 인해 운영체제의 수정이 불가피한 상황이다. 또한 운영체제의 수정은 호환성의 결여라는 문제를 야기시킨다. 이를 위해 사용하는 방식이 Middleware 방식이다. 실시간 시스템 지원 Middleware 는 운영체제와 실시간 지원 응용프로그램 사이에 위치하여 운영체제 자제가 가지고 있는 부족한 실시간성을 보완하여 주고, 응용프로그램이 적절하고 효과적으로 시스템 서비스들을 이용할 수 있게 해준다. 본 논문에서는 Middleware가 부족간 실시간성을 보완하기 위하여 사용할 수 있는 Middleware 스케줄러의 방식에 대하여 논하고, 효율적인 설계방식을 제안한다.

• Proceedings of the IEEK Conference
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• 1998.06a
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• pp.839-842
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• 1998

The wide spread of multimedia system demands a large viewin gdesply device which can inform a message to many peoples in open area. This paper is about the design, simulating and testing of a large viewing LED pannel control ASIC(application specific integrated circuit). This LED pannel control ASIC runs on 16 bit microprocessor MC68EC000 and has following functions:16 line interlaced LED pannel controller, memory controller, 16 channel priority inerrupt controller, 2 channel direct memory access controller, 2 channel 12 bit clock and timer, 2 channel infrared remocon receiver, 2 channel RS-232C with 16byte FIFO, IBM PC/AT compatible keyboard interface, battery backuped real time clock, ISA bus controller, battery backuped 256 byte SRAM and watech dog timer. The 0.6micron CMOS sea of gate is used to design the ASIC in amount of about 39,000 gates.

• Proceedings of the Korean Society of Computer Information Conference
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• 2017.01a
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• pp.3-4
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• 2017

본 논문에서는 가상화 기술을 지원하는 ARMv7 Cortex-A15 프로세서가 탑재된 임베디드 보드를 위한 실시간 운영체제(RTOS) 구현을 위한 방법을 제안한다. ARM Cortex-A15 프로세서가 지원하는 Generic Interrupt Controller와 Generic Timer에 대해 알아보고, 가상화 시스템에서 인터럽트 오버헤드를 줄이는 GICv2와 가상 타이머인 Generic Timer를 사용하여 실시간 운영체제인 FreeRTOS를 임베디드 보드에 이식하였다.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.32A no.5
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• pp.42-53
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• 1995

Token bus protocols have been sidely accepted for Medium Access Control (MAC) in real-time networks such as those used in factory automation, distributed process control, nuclear power plant, aircraft and spacecraft. Token bus protocols provide timer-controlled priority mechanism, which offers multiple level of privilege of medium access to different type of traffic. This paper presents and approximate analytical model for the evaluation of variance of waiting time in the time-controlled proiority scheme of token bus protocols. Token bus system is assumed to be operated with singe-service discipline which is the practical case of real-time networks such as those used in distributed process control and factory automations. The approximate analytical model is validated by comparison with the simulation resuls.

• The KIPS Transactions:PartC
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• v.11C no.6 s.95
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• pp.799-806
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• 2004

A growing diversity of pervasive devices is gaming access to the Internet and other information. However, much of the rich multimedia contents cannot be easily handled by the client devices because of the limited communication, processing, storage and display capabilities. The in-tegration of voice, data and video service modified the target of networking technologies. Networks must have some the capabilities for in-tegration of various services and also for QoS support as required by each of those service. Because of these reasons, we developed EAGIS(Efficient ATM Gateway for real time Internet Service) to provide seamless multimedia service between the ATM network and the Internet. EAGIS consists of the interworking unit, content server, transcoding server, and the serveice broker to provide seamless multimedia service be-tween the ATM network and the Internet. In this paper, we design the architecture and transcoding service scenario of the EAGIS. When the RTP is used for the bi-directional communication, transcoding time is configured by the time-stamp of RTCP. When HTTP is used for unidirec-tional communication, self-timer is used. By using these reference time, standard transcoding method is applicable according to the frame trans-mission rate and network traffic load. And we can also assure the QoS of the multiple users` effective bandwidth by our algorithm.