• 제목/요약/키워드: Real-time communications

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RTOS-기반 임베디드 소프트웨어를 위한 모델기반 개발방법 (Model-Driven Development of RTOS-based Embedded Software)

  • 맹지찬;김종혁;유민수
    • 한국정보처리학회:학술대회논문집
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    • 한국정보처리학회 2006년도 춘계학술발표대회
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    • pp.1325-1328
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    • 2006
  • 본 논문에서는 RTOS 기반 임베디드 소프트웨어 개발에 적합한 모델기반 방법론을 제안하고 이와 함께 개발된 자동코드생성 도구를 기술한다. 현재까지 알려진 대표적인 모델기반 방법론으로는 OMG (Object Management Group)의 MDA (Model-Driven Architecture)가 있으며, MDA 에서는 EJB, 웹서비스,.NET, 그리고 CORBA 와 같은 미들웨어 플랫폼을 대상으로 하는 응용 소프트웨어의 개발을 지원한다. 하지만, 통상적인 임베디드 시스템은 실시간성에 대한 요구조건은 물론 성능과 자원활용에 있어 많은 제약을 가짐에 따라 상당수의 임베디드 시스템은 미들웨어를 사용하지 않고 RTOS 상에서 직접 수행되도록 개발되고 있다. 이에 따라 본 연구에서는 MDA 방법론을 확장하여 플랫폼 의존적인 모델 (PSM, Platform Specific Model) 단계에서 추상화된 RTOS 행위를 표현할 수 있도록 추상 RTOS API (Generic RTOS API)를 정의하고, 아울러 추상화된 RTOS 행위를 자동으로 변환하여 C 코드를 생성해주는 도구인 TransPI 를 함께 제시한다.

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Quick Evaluations of the KOMPSAT-1 Orbit Maneuvers Using Small Sets of Real-time GPS Navigation Solutions

  • Lee, Byoung-Sun;Lee, Jeong-Sook;Kim, Jae-Hoon
    • Transactions on Control, Automation and Systems Engineering
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    • 제3권3호
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    • pp.196-202
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    • 2001
  • Quick evaluations of two in-plane orbit maneuvers using small sets of real-time GPS navigation solutions were performed for the KOMPSAT-1 spacecraft operation. Real-time GPS navigation solutions of the KOMPSAT-1 were collected during the Korean Ground Station(KGS) pass. Only a few sets of position and velocity data after completion of the thruster firing were used for the quick maneuver evaluations. The results were used for antenna pointing data predictions for the next station contact. Normal orbit maneuver evaluations using large sets of playback GPS navigation solutions were also performed and the result were compared with the quick evaluation results.

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Quick Evaluation of Spacecraft Orbit Maneuver Using Small Sets of Real-time GPS Navigation Solutions

  • Lee, Byoung-Sun;Lee, Ho-Jin;Lee, Seong-Pal;Kim, Jong-Ah;Park, Hae-Jin
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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    • pp.458-458
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    • 2000
  • Quick evaluations of two in-plane orbit maneuvers using small see of real-time CPS navigation solutions were peformed lot the KOMPSAT-1 spacecraft operation. Real-time GPS navigation solutions of the KOMPSAT-1 were collected during the Korean Ground Station(KGS) pass. Only a few sets of position and velocity data after completion of the thruster firing were used for the quick maneuver evaluations. The results were used for antenna pointing data predictions for the next station contact. Normal orbit maneuver evaluations using large see of playback GPS navigation solutions were also performed and the result were compared with the quick evaluation results.

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ArUco 마커 기반 실시간 인장변형률 측정 시스템 (Real-time Tensile Strain Measurement System based on ArUco Marker)

  • 이승아;김도현;김윤
    • 한국멀티미디어학회논문지
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    • 제24권6호
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    • pp.753-759
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    • 2021
  • During tensile test, tensile strain of tensile tester is measured by movement distance of upper zig and initial specimen's length. Conventional tensile tester program obtains the tensile strain after the end of the test, however the method is not appropriate in real time because the results are calculated until the test is finished. We suggest a real-time measurement system of tensile strain using ArUco Marker in OpenCV library. The system is designed to detect marker attached on the upper zig and calculate specimen's tensile strain. According to comparison of the calculated data and the results of the tester, errors approximately showed 0.128 mm on 3840×2160 video resolution.

Quality Adaptation of Intra-only Coded Video Transmission over Wireless Networks

  • Shu Tang;Yuanhong Deng;Peng Yang
    • Journal of Information Processing Systems
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    • 제19권6호
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    • pp.817-829
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    • 2023
  • Variable wireless channel is a big challenge for real-time video applications, and the rate adaptation of realtime video streaming becomes a hot topic. Intra-video coding is important for high-quality video communication and industrial video applications. In this paper, we proposed a novel adaptive scheme for real-time video transmission with intra-only coding over a wireless network. The key idea of this scheme is to estimate the instantaneous remaining capacity of the network to adjust the quality of the next several video frames, which not only can keep low queuing delay and ensure video quality, but also can respond to bandwidth changes quickly. We compare our scheme with three different schemes in the video transmission system. The experimental results show that our scheme has higher bandwidth utilization and faster bandwidth change response, while maintaining low queuing delay.

지적 아바타 통신을 위한 얼굴 표정의 실시간 생성에 관한 검토 (An Empirical Study on Real-time Generation of Facial Expressions in Avatar Communications)

  • 이용후;김상운;일본명
    • 대한전자공학회:학술대회논문집
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    • 대한전자공학회 2003년도 하계종합학술대회 논문집 Ⅲ
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    • pp.1673-1676
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    • 2003
  • As a means of overcoming the linguistic barrier in the Internet cyberspace, recently a couple of studies on intelligent avatar communications between avatars of different languages such as Japanese-Korean have been performed. In this paper we measure the generation time of facial expressions on different avatar models in order to consider avatar models to be available in real-time system. We also provide a short overview about DTD (Document Type Definition) to deliver the facial and gesture animation parameters between avatars as an XML data.

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TMS320C64x 기반 MPEG-1 LayerII Decoder의 DSP 구현 (Implementation of the MPEG-1 Layer II Decoder Using the TMS320C64x DSP Processor)

  • 조충상;이영한;오유리;김홍국
    • 대한전자공학회:학술대회논문집
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    • 대한전자공학회 2006년도 하계종합학술대회
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    • pp.257-258
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    • 2006
  • In this paper, we address several issues in the real time implementation of MPEG-1 Layer II decoder on a fixed-point digital signal processor (DSP), especially TMS320C6416. There is a trade-off between processing speed and the size of program/data memory for the optimal implementation. In a view of the speed optimization, we first convert the floating point operations into fixed point ones with little degradation in audio quality, and then the look-up tables used for the inverse quantization of the audio codec are forced to be located into the internal memory of the DSP. And then, window functions and filter coefficients in the decoder are precalculated and stored as constant, which makes the decoder faster even larger memory size is required. It is shown from the real-time experiments that the fixed-point implementation enables us to make the decoder with a sampling rate of 48 kHz operate with 3 times faster than real-time on TMS320C6416 at a clock rate of 600 MHz.

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스위칭이더넷에서 주기적 메시지에 대한 경성 실시간 통신을 위한 메시지 스케쥴링 알고리즘 (Message Scheduling Algorithm for Hard Real-time Communications of Periodic Messages on a Switched Ethernet)

  • 김명균;이희찬
    • 한국정보과학회논문지:시스템및이론
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    • 제33권9호
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    • pp.684-690
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    • 2006
  • 본 논문에서는 스위칭이더넷에서의 주기적 메시지에 대해 경성 실시간 통신을 위한 메시지 전송 모델을 제안하고, 각 메시지들을 마감시간 안에 전송하기 위한 메시지 스케쥴링 알고리즘을 제안한다. 제안하는 스케쥴링 알고리즘은 중앙노드 없이 동작하는 분산 알고리즘이고 스위치에 새로운 기능의 추가없이 송신자와 수신자 노드 사이에서 동작한다. 제안한 알고리즘은 새로운 주기적 메시지에 대한 전송요청이 오면 이미 스케쥴 되어 있는 주기적 메시지에 영향을 미치지 않고 송신 링크와 수신 링크에서 스케쥴링 가능한지 검사를 하고, 스케쥴링이 가능하면 전송 스케쥴을 생성한다. 본 논문에서 제안하는 스케쥴링 알고리즘은 스위칭이더넷에서 주기적 메시지에 대해 마감시간 내 전송을 보장하고, 새로운 메시지에 대한 동적인 추가가 용이하여 경성 실시간 시스템에서 유연한 메시지 전송 기법을 제공한다.

기계학습 기반의 실시간 이미지 인식 알고리즘의 성능 (Performance of Real-time Image Recognition Algorithm Based on Machine Learning)

  • 선영규;황유민;홍승관;김진영
    • 한국위성정보통신학회논문지
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    • 제12권3호
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    • pp.69-73
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    • 2017
  • 본 논문에서는 기계학습 기반의 실시간 이미지 인식 알고리즘을 개발하고 개발한 알고리즘의 성능을 테스트 하였다. 실시간 이미지 인식 알고리즘은 기계 학습된 이미지 데이터를 바탕으로 실시간으로 입력되는 이미지를 인식한다. 개발한 실시간 이미지 인식 알고리즘의 성능을 테스트하기 위해 자율주행 자동차 분야에 적용해보았고 이를 통해 개발한 실시간 이미지 인식 알고리즘의 성능을 확인해보았다.

A Measurement-Based Adaptive Control Mechanism for Pricing in Telecommunication Networks

  • Davoli, Franco;Marchese, Mario;Mongelli, Maurizio
    • Journal of Communications and Networks
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    • 제12권3호
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    • pp.253-265
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    • 2010
  • The problem of pricing for a telecommunication network is investigated with respect to the users' sensitivity to the pricing structure. A functional optimization problem is formulated, in order to compute price reallocations as functions of data collected in real time during the network evolution. No a-priori knowledge about the users' utility functions and the traffic demands is required, since adaptive reactions to the network conditions are sought in real time. To this aim, a neural approximation technique is studied to exploit an optimal pricing control law, able to counteract traffic changes with a small on-line computational effort. Owing to the generality of the mathematical framework under investigation, our control methodology can be generalized for other decision variables and cost functionals.