• Title/Summary/Keyword: realtime simulation

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A study on the design and implementation of the transport protocol for Audio/Video data transmission (음성 및 화상 데이타 전송을 위한 트랜스포트 프로토콜의 설계 및 구현에 관한 연구)

  • Kim, June;Lee, Kwang-Hui;An, Sun-Shin
    • Proceedings of the KIEE Conference
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    • 1987.07b
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    • pp.1053-1057
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    • 1987
  • In this paper, we have studied a communication protocol which may provide Audio/Video data transmission in real time. Auido/Video data have its own characteristics. A new transport protocol with realtime constraint has been designed and implemented which performs dynamic error control and flow control depending on the characteristics of transmitted Audio/Video data. Since the receiving data can be predicted from the previously received data using the prediction function in Auido/Video data transmission, these functions are introduced in our transport protocol that may possibly improve the speed of data transmission and give a real time response. We have tested our transport protocol and measured the performance by the simulation. We assume that our transport protocol would be used in LAN environment. Our prime purpose is to provide a reliable and real time Auido/Video data transmission service.

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Simulation Study for the Application of NURBS Interpolator (CNC공작기계에 NURBS 보간 알고리즘 적용을 위한 시뮬레이션 분석)

  • 김태훈;고태조;김희술
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2001.04a
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    • pp.979-982
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    • 2001
  • In CNC machining, demands on precision machining of free formed surface model are increasing. Most of the CAD/CAM systems provide the NURBS(Non-Uniform Rational B-Spline) interpolator. NURBS is defined with NURBS parameter by control point, weight value and knot value. This paper shows the realtime NURBS interpolation algorithms and compared with each other. One is based on the equal length of curve segments rather than equal increment of the parameter Δu. The other is to limit the interpolation error to any desired level by adjusting the feedrate considering the curvature of the shape and sampling time.

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A new timing structure for a realtime communication (실시간 통신을 위한 새로운 Timing 구조)

  • 김경재;신동렬
    • Proceedings of the IEEK Conference
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    • 1999.11a
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    • pp.771-774
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    • 1999
  • This paper presents a new timing structure for real time communications and its performance analysis. The cycle time consists of several "one time slot" which may be an interval defined by a synchronous traffic part followed by an asynchronous traffic part. If a station receives a token within a synchronous interval, it transmits its synchronous message if any, otherwise it may transmit an asynchronous message. This scheme is different from usual allocation schemes which divide one cycle into alternating synchronous and asynchronous subslots. This protocol is designed to prevent low priority messages from delaying too much due to lots of high priority messages. We propose the algorithm and show its justification by simulation.

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Voltage Regulation Method at the Power Distribution System interconnected with DSG System (분산형전원이 연계된 배전계통의 전압조정에 관한 연구)

  • Choi, Joon-Ho;Chu, Dong-Wook;Kim, Jae-Chul;Hwang, Chi-Woo
    • Proceedings of the KIEE Conference
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    • 1997.11a
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    • pp.250-252
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    • 1997
  • This paper deals with voltage regulation at the power Distribution system interconnected with DSG. Modern distribution substation adopt LDC method as the voltage regulation method to deliver suitable voltages to many customers. However, the operations of DSG interconnected with distribution system, the customers' voltage violate the permissible voltage limits. Therefore, to deliver suitable voltage to many customers at the distribution substation, an advanced voltage regulation method is required. In this paper, the on line realtime MLDC (Multiple Line Drop compensation) method, considered daedband and hysterical tap changing of the ULTC, is proposed. The result from a simulation study shows that the proposed method can be practical applications for the voltage regulation at the distribution system interconnected with DSG and unbalanced load pattern among feeders.

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Development of A Lossless Video Coding System Using Motion Compensation

  • Naoki Ono;Satoshi Ishbashi;Naoki Kobayashi
    • Proceedings of the Korean Society of Broadcast Engineers Conference
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    • 1998.06b
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    • pp.177-182
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    • 1998
  • In this paper, we propose a lossless motion video coding method using motion compensation. For realtime coding and transmission, we developed a lossless video codec based on the proposed method. It was confirmed the codec functions normally in an experiment involving coding and transmitting through an actual ATM network. Furthermore, we proposed a lossless coding method with bit-plane expansion under a constant bitrate. Two approaches, a closed bit-plane approach and a merged bit-plane approach, are considered and characteristics of their compression efficiency are estimated. Simulation results show that the proposed method is suitable for lossless video coding with bitrate control.

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Dynamics modeling of a GHP in cooling mode for development of control algorithm (제어 알고리즘 개발을 위한 GHP 냉방모드 동특성 모델링)

  • Shin Younggy;Kim Young Il
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.17 no.3
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    • pp.243-249
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    • 2005
  • The present study has been conducted to simulate dynamics of a gas engine-driven heat pump(GHP) for design of control algorithm. The dynamic modeling of a GHP was based on conservation laws of mass and energy. For automatic control of refrigerant pressures, actuators such as engine speed, outdoor fan, coolant three-way valves and liquid injection valve were PI or P controlled. The simulation results showed physical behavior that is realistic enough to apply for control algorithm design.

Environment Dependent Coherence of a Short DNA Charge Transfer System

  • Kim, Hee-Young;Lee, Myeong-Won;Sim, Eun-Ji
    • Bulletin of the Korean Chemical Society
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    • v.28 no.4
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    • pp.607-612
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    • 2007
  • Relationship between charge transfer mechanism and quantum coherence has been investigated using a realtime quantum dynamics approach. In the on-the-fly filtered propagator functional path integral simulation, by separating paths that belong to different mechanisms and by integrating contributions of correspondingly sorted paths, it was possible to accurately obtain quantitative contribution of different transport mechanisms. For a 5'-GAGGG-3' DNA sequence, we analyze charge transfer processes quantitatively such that the governing mechanism alters from coherent to incoherent charge transfer with respect to the friction strength arising from dissipative environments. Although the short DNA sequence requires substantially strong dissipation for completely incoherent hopping transfer mechanism, even a weak system-environment interaction markedly destroys the coherence within the quantum mechanical system and the charge transfer dynamics becomes incoherent to some degree. Based on the forward-backward path deviation analysis, the coherence variation depending on the environment is investigated numerically.

Traffic Aided Uplink Opportunistic Scheduling with QoS Support in Multiservice CDMA Networks

  • Liao, Dan;Li, Lemin
    • ETRI Journal
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    • v.29 no.1
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    • pp.120-123
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    • 2007
  • In this letter, we address the problem of resource allocation with efficiency and quality of service (QoS) support in uplink for a wireless CDMA network supporting real-time (RT) and non-realtime (NRT) communication services. For RT and NRT users, there are different QoS requirements. We introduce and describe a new scheme, namely, traffic aided uplink opportunistic scheduling (TAUOS). While guaranteeing the different QoS requirements, TAUOS exploits the channel condition to improve system throughput. In TAUOS, the cross-layer information, file size information, is used to improve fairness for NRT users. Extensive simulation results show that our scheme can achieve high system throughput in uplink wireless CDMA systems, while guaranteeing QoS requirements.

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Realtime Face Recognition by Analysis of Feature Information (특징정보 분석을 통한 실시간 얼굴인식)

  • Chung, Jae-Mo;Bae, Hyun;Kim, Sung-Shin
    • Journal of the Korean Institute of Intelligent Systems
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    • v.11 no.9
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    • pp.822-826
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    • 2001
  • The statistical analysis of the feature extraction and the neural networks are proposed to recognize a human face. In the preprocessing step, the normalized skin color map with Gaussian functions is employed to extract the region of face candidate. The feature information in the region of the face candidate is used to detect the face region. In the recognition step, as a tested, the 120 images of 10 persons are trained by the backpropagation algorithm. The images of each person are obtained from the various direction, pose, and facial expression. Input variables of the neural networks are the geometrical feature information and the feature information that comes from the eigenface spaces. The simulation results of 10 persons show that the proposed method yields high recognition rates.

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Resource Allocation to Support QoE of Handovers in Overlaid Macro-Femto Networks

  • Lee, Moon-Ho;Lee, Jong-Chan
    • Journal of the Korea Society of Computer and Information
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    • v.21 no.12
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    • pp.73-79
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    • 2016
  • This paper proposes a novel resource allocation scheme which enables to guarantee the quality of experience (QoE) for handovers from femtocell to macrocell and vice versa, and between femtocells in the overlaid macro-femto networks. The proposed scheme guarantees QoE to a certain extent during handover by utilizing a fixed amount of radio resource reserved in advance for the dedicated use to support QoE. We take both the type of the handover and the temporal sensitiveness characteristics of user services into consideration in order to support QoE. Performance of our scheme is analyzed by simulation with respect to the outage probability and total throughput.