• Title/Summary/Keyword: Real_time

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Overview of Real-Time Java Computing

  • Sun, Yu;Zhang, Wei
    • Journal of Computing Science and Engineering
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    • v.7 no.2
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    • pp.89-98
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    • 2013
  • This paper presents a complete survey of recent techniques that are applied in the field of real-time Java computing. It focuses on the issues that are especially important for hard real-time applications, which include time predictable garbage collection, worst-case execution time analysis of Java programs, real-time Java threads scheduling and compiler techniques designed for real-time purpose. It also evaluates experimental frameworks that can be used for researching real-time Java. This overview is expected to help researchers understand the state-of-the-art and advance the research in real-time Java computing.

A Proposal of the Real time Optimal Route Algorithm With Window mechanism (윈도우 매커니즘을 이용한 실시간 최적경로 추출 알고리즘 제안)

  • 이우용;하동문;신준호;김용득
    • Proceedings of the IEEK Conference
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    • 1999.06a
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    • pp.737-740
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    • 1999
  • This paper deals with a real time optimization algorithm within real time for DRGS(Dynamic Route Guidance System) and evaluate the algorithm. A pre-developed system offers the optimal route in using only static traffic information. In using real-time traffic information, Dynamic route guidance algorithm is needed. The serious problem in implementing it is processing time increase as nodes increase and then the real time processing is impossible. Thus, in this paper we propose the optimal route algorithm with window mechanism for the real-time processing and then evaluate the algorithms.

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Scheduling of Real-time and Nonreal-time Traffics in IEEE 802.11 Wireless LAN (무선랜에서의 실시간 및 비실시간 트래픽 스케줄링)

  • Lee, Ju-Hee;Lee, Chae Y.
    • Journal of the Korean Operations Research and Management Science Society
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    • v.28 no.2
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    • pp.75-89
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    • 2003
  • Media Access Control (MAC) Protocol in IEEE 802.11 Wireless LAN standard supports two types of services, synchronous and asynchronous. Synchronous real-time traffic is served by Point Coordination Function (PCF) that implements polling access method. Asynchronous nonreal-time traffic is provided by Distributed Coordination Function (DCF) based on Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) protocol. Since real-time traffic is sensitive to delay, and nonreal-time traffic to error and throughput, proper traffic scheduling algorithm needs to be designed. But it is known that the standard IEEE 802.11 scheme is insufficient to serve real-time traffic. In this paper, real-time traffic scheduling and admission control algorithm is proposed. To satisfy the deadline violation probability of the real time traffic the downlink traffic is scheduled before the uplink by Earliest Due Date (EDD) rule. Admission of real-time connection is controlled to satisfy the minimum throughput of nonreal-time traffic which is estimated by exponential smoothing. Simulation is performed to have proper system capacity that satisfies the Quality of Service (QoS) requirement. Tradeoff between real-time and nonreal-time stations is demonstrated. The admission control and the EDD with downlink-first scheduling are illustrated to be effective for the real-time traffic in the wireless LAN.

Aesthetics of Interactive Real-Time 3D (인터렉티브 리얼 타임 3D 아트의 미학적 특성)

  • Dho, Soon-Ho
    • Journal of Korea Game Society
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    • v.5 no.2
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    • pp.3-9
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    • 2005
  • Interactive real-time 3D enables users to explore virtual three dimensional environments and also experience contents in an absorbing fashion. Unlike other media, Interactive real-time 3D users take an active role in the process of "real-time fashion" where action and reaction occur instantly in a digital 3D structure. Once the components and origins of interactive real-time 3D is made, it is possible making principles of the beauty that help decide success or failure of real-time 3D in two way system. Substantial real-time 3D has not yet passed 10 years so it was unable to make sufficient precedents of fundamental artistic value based upon the credibility of the media. The goal is to explain the new form of design in relation to general principles of arts at the same time to understand the technical definition better. Concepts of historical documentation are explained with an example of categorization of recent video game and recent technology. This thesis concludes with rough forecast on the future interactive real time 3D. Since the medium began relatively recently and is developing in the rapid pace, recent analyses, though clear forecast is difficult, tend to investigate potential directions to some level the field allows.

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Real-Time Kernel for Linux based on ARM Processor, RTiKA (Real-Time Implant Kernel For ARMLinux) (ARM 프로세서 기반의 리눅스를 위한 실시간 확장 커널 (RTiKA, Real-Time implant Kernel for ARMLinux))

  • Lee, Seung-Yul;Lee, Sang-Gil;Lee, Cheol-Hoon
    • The Journal of the Korea Contents Association
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    • v.17 no.10
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    • pp.587-597
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    • 2017
  • Recently, the demand for real-time performance in mobile environment is increasing due to the improvement of hardware performance, however a GPOS(General-Purpose Operating System) such as Android and Linux do not provide real-time performance. We developed RTiK(Real-Time implant Kernel) for this problem, but it has the disadvantage of supporting only x86 Architecture. In this paper, we designed and implemented a RTiKA(Real-Time implanted Kernel for ARM) to support real-time in ARM Linux. We used MCT(Multi-Core Timer) timer which replaces Local APIC Timer for real-time support, and we measured the period of generated real-time task for performance verification and evaluation. As the recent the RTiKA can guarantee the operating of several real-time tasks based on the cycle of 1ms.

Real-Time Object Model dRTO (실시간 객체 모델 dRTO)

  • Lee, Sheen;Son, Hyuk-Su;Yang, Seung-Min
    • Journal of KIISE:Computer Systems and Theory
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    • v.27 no.3
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    • pp.300-312
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    • 2000
  • The application areas of embedded real-time systems are very wide and so are the requirements for real-time processing and reliability of the systems. To develop embedded real-time systems effectively with its real-time and reliability properties guaranteed, an appropriate real-time model is needed. Recently, the research on real-time object-oriented model is active, which graft the concept of object-orientation on real-time systems modeling and development. In this paper, we propose dRTO (dependable Real-Time Object) model, with 5 primitive classes. These allow designers to effectively model the characteristics of real-time systems, i.e., object-orientation, real-time-ness and dependability. The dRTO model has three main features. First, it is able to model and implement the timing constraints imposed on real-time objects as well as interactions among the objects. Second, hardware and software components (including kernel) of embedded systems can be modeled in one frame. Third, it is able to represent fault detection and recovery mechanisms explicitly.

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A Dual Real-Time Scheduling Design under Real-Time Constraints Kernel Environments (실시간 제약 커널 환경하에서의 이중 실시간 스케쥴링 설계)

  • 인치호
    • The Transactions of the Korean Institute of Power Electronics
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    • v.6 no.4
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    • pp.369-375
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    • 2001
  • This paper proposes a dual real-time scheduling design under real-time constraints kernel environments. In this paper, we have designed both the real-time kernel and the general kernel that have their different properties to satisfy these properties, that is, interrupt latency, scheduling precision, and message passing. In real-time tasks, interrupt processing should be run. In general kernel, non real-time tasks or general tasks are run. Also, when tasks conflict, it executed the mixed priority scheduling that non real-time kernel executed static scheduling and real-time kernel executed dynamic priority transformation scheduling, that is, least-laxity-first/minimization preemption scheduling. We have compared the results of this study for performance of the proposal real-time kernel with both RT Linux 0.5a and QNX 4.23A, that is, of interrupt latency scheduling precision and message passing.

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Implementation of Dual-Kernel based Control System and Evaluation of Real-time Control Performance for Intelligent Robots (지능형 로봇을 위한 이중 커널 구조의 제어 시스템 구현 및 실시간 제어 성능 분석)

  • Park, Jeong-Ho;Yi, Soo-Yeong;Choi, Byoung-Wook
    • Journal of Institute of Control, Robotics and Systems
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    • v.14 no.11
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    • pp.1117-1123
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    • 2008
  • This paper implements dual-kernel system using standard Linux and real-time embedded Linux for the real-time control of intelligent robot systems. Such system provides more useful services including standard Linux thread that is easy to implement complicated tasks and real-time tasks for the deterministic response to velocity control. Here, an open source real-time embedded Linux, XENOMAI, is ported on embedded target board. And for interfacing with motor controller we adopted a real-time serial device driver. The real-time task was implemented with a priority to keep the cyclic control command for trajectory control. In order to validate deterministic response of the proposed system, the performance measurement of the delay in performing trajectory control with feedback loop is evaluated with non real-time standard Linux. The proposed software architecture is anticipated to take advantage of features in both standard Linux and real-time operating systems for the intelligent robot systems.

A Research of Real-time Rendering Potentials on 3D Animation Production

  • Ke Ma;Jeanhun Chung
    • International journal of advanced smart convergence
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    • v.12 no.4
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    • pp.293-299
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    • 2023
  • In recent years, with the rapid development of real-time rendering technology, the quality of the images produced by real-time rendering has been improving, and its application scope has been expanded from games to animation and advertising and other fields. This paper analyses the development status of real-time rendering technology in 3D animation by investigating the 3D animation market in China, which concludes that the number of 3D animations in China has been increasing over the past 20 years, and the number of 3D animations using real-time rendering has been increasing year by year and exceeds that of 3D animations using offline rendering. In this study, a real-time rendering and offline rendering 3D animation are selected respectively to observe the screen effect of characters, special effects and environment props, and analyse the advantages and disadvantages of the two rendering technologies, and finally conclude that there is not much difference between real-time rendering 3D animation and offline rendering 3D animation in terms of quality and the overall sense of view, and due to the real-time rendering of the characteristics of the WYSIWYG, the animation designers can better focus on the creation of art performance. Real-time rendering technology has a good development prospect and potential in 3D animation, which paves the way for designers to create 3D content more efficiently.

Admission Control Algorithm for Real-Time Packet Scheduling (실시간 패킷 스케줄링을 위한 수락 제어 알고리즘)

  • Ryu Yeonseung;Cho Sehyeong;Won Youjip
    • Journal of Korea Multimedia Society
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    • v.7 no.9
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    • pp.1273-1281
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    • 2004
  • There have been a number of researches on real-time packet scheduling based on EDF algorithm to support end-to-end delay bound guarantees for real-time traffic transmission. However, EDF-based packet scheduler could not guarantee the real-time requirements of real-time traffic if there exist non-real-time traffic. In this paper, we propose a new admission control algorithm and packet scheduling scheme considering non-real-time traffic in the real -time packet scheduler based on EDF policy. Proposed admission control algorithm has pseudo-polynomial time complexity, but we show through simulation that it can be used with little run-time overhead.

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