• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2006.11a
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• pp.289-292
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• 2006

In this paper, a wireless control network based on IEEE 802.15.4 MAC protocol is proposed. The superframe of IEEE 802.15.4 is applied to the proposed wireless control network. The transmission and bandwidth management method are proposed for efficient transmission in the superframe. By these methods, the proposed wireless control network protocol is able to transmit three types of data (periodic data, sporadic data, and non real-time message), and guarantee real-time transmission within deadline.

• Smart Media Journal
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• v.4 no.3
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• pp.24-30
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• 2015

For suddenly encountered emergencies, most people embarrass, and can not often deliver the correct message when they report. Recently in the commonplace smart software environment, it is important that they can transmit the correct individual emergency situation efficiently and can receive the best service, and can provide the efficient emergency medical services to real-time around the other emergencies. In this paper, we design a standard protocol for the rapid and accurate technology for transmitting XML-based structured messages to provide an efficient emergency medical services, and offers a emergency medical services protocol to make them available more efficiently.

• Journal of Communications and Networks
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• v.15 no.1
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• pp.87-101
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• 2013

In industrial applications, sensor networks have to satisfy specified time requirements of exchanged messages. IEEE 802.15.4 defines the communication protocol of the physical and medium access control layers for wireless sensor networks, which support real-time transmission through guaranteed time slots (GTSs). In order to improve the performance of IEEE 802.15.4 in industrial applications, this paper proposes a new traffic scheduling algorithm for GTS. This algorithm concentrates on time-critical industrial periodic messages and determines the values of network and node parameters for GTS. It guarantees real-time requirements of periodic messages for industrial automation systems up to the order of tens to hundreds of milliseconds depending on the traffic condition of the network system. A series of simulation results are obtained to examine the validity of the scheduling algorithm proposed in this study. The simulation results show that this scheduling algorithm not only guarantees real-time requirements for periodic message but also improves the scalability, bandwidth utilization, and energy efficiency of the network with a slight modification of the existing IEEE 802.15.4 protocol.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.350-353
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• 2004

The increasing use of Ethernet-TCP/IP network in industry has led to the growing interest in its reliability in real-time applications such as automated manufacturing systems and process control systems. However, stochastic behavior of its medium access scheme makes it inadequate for time-critical applications. In order to guarantee hard real-time communication service in Ethernet-TCP/IP network, we proposed an algorithm running over TCP/IP protocol stack without modification of protocols. In this paper, we consider communication services guaranteeing deadlines of periodic real-time messages over MAC protocols that have unbounded medium access time. We propose a centralized token scheduling scheme for multiple access networks. The token is used to allow a station to transmit its message during the time amount that is appended to the token. The real-time performance of the proposed algorithm has been described.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.549-549
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• 2000

In the previous work, we dealt with a traffic analysis of network-based control system and its architecture using the CAN protocol. It is difficult to determine an optimal network architecture for a specific system. In this paper, we propose the architecture of network-based control system applicable to a specific AGV system with manipulator arms. We define the fixed number of periodic messages to be occurred in this system. In the proposed system architecture, we analyse its traffic for the real-time communication of all messages, determine the optimal sampling period of an analog sensor to be satisfied with the required specification and the number of possible sensors to be added through simulation.

• Journal of Korea Multimedia Society
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• v.12 no.5
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• pp.617-632
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• 2009

In this paper we propose a technique of implementing the reconfigurable network protocol stack that allows for partitioning network protocol functions into software and hardware tasks on a SoC (System on Chip) platform. Additionally, we present a method that guarantees the deadline of both an individual task and messages exchanging among tasks in order to meet the deadline of real-time multimedia and networking services. The proposed real-time message exchange method guarantees the deadline of messages generated by multimedia services that are required to meet the real-time properties of multimedia applications. After implementing the networking functions of TCP/IP protocol suite into hardware and software tasks, we verify and validate their performance on the SoC platform. Experimental results indicate that the proposed technique improves the performance of TCP/IP protocol suit as well as application service satisfaction in application-specific real-time.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.155-155
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• 2000

A high performance control and monitoring system for a high speed railway train requires a reliable the real-time communication network. TCN/WTB is designed for the data transmission over the train bus, and UIC556 defines that all the data be transmitted over TCN/WTB. This paper evaluates the performance of the link layer of WTB(Wired Train Bus). The evaluated results can be used for the selection of parameters for the sporadic message data.

• Journal of information and communication convergence engineering
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• v.9 no.2
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• pp.244-250
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• 2011

Gossip is a well-known protocol which was proposed to implement broadcast service with a high reliability in an arbitrarily connected network of sensor nodes. The probabilistic techniques employed in gossip have been used to address many challenges which are caused by flooding in wireless sensor networks (WSNs). However, very little work has yet been done on real-time wireless sensor networks which require not only highly reliable packets reception but also strict time constraint of each packet. Moreover, the unique energy constraining feature of sensor makes existing solutions unsuitable. Combined with unreliable links, redundant messages overhead in real-time wireless sensor networks is a new challenging issue. In this paper, we introduce a Reliable Gossip Zone, a novel fine-tailored mechanism for real-time wireless sensor networks with unreliable wireless links and low packet redundancy. The key idea is the proposed forwarding probability algorithm, which makes forwarding decisions after the realtime flooding zone is set. Evaluation shows that as an oracle broadcast service design, our mechanism achieves significantly less message overhead than traditional flooding and gossip protocols.

• Proceedings of the Korean Information Science Society Conference
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• 2004.04a
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• pp.460-462
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• 2004

분산 환경에서의 효과적인 통신 방법인 멀티캐스트 프로토콜이 그동안 많이 연구되었다. 하지만 인터넷 기반 네트워크의 급속한 발달로 실시간 데이터를 요구하는 환경으로 변화함에 따라 실시간 멀티캐스트 프로토콜의 필요성이 대두되었다. 실시간 프로토콜 중 하나인 RFRM(Release-time based Fault-tolerant Real-time Multicast protocol)은 메시지의 신뢰성을 보장하고 뷰의 일관성을 유지하며 고장을 감내한다는 장점이 있지만 한 개의 그룹만을 지원한다는 단점을 가지고 있다. 따라서 본 논문에서는 실시간 멀티캐스트 프로토콜인 RFRM을 확장하여 멀티그룹을 지원하는 뷰 관리기능을 추가하였고, 그 성능을 분석하기 위하여 Erlang/OTP를 사용하여 구현된 결과를 TMO(Time-triggered Message-triggered Object) 모델을 사용한 실시간 시뮬레이션의 결과와 기존의 RFRM의 그룹 연산 성능과 비교하였다.

• Journal of Korea Multimedia Society
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• v.20 no.8
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• pp.1439-1446
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• 2017

Steady exercise or walking exercise is helpful for the treatment of chronic diseases or cancers. In this paper, I presented a smart poster to enable the patients to exercise while moving between the smart posters, dynamically, in order to provide better exercise effect to them. It can be a new form of exercise prescription that combines exercise with walking using smart posters. The personalized exercise prescription is downloaded from the management server in real time when the patient approaches, and induces the patient's exercise and walking. In addition, the smart poster helps patient to move to other posters in order to induce more walking exercise. To achieve this, I proposed a transfer protocol that autonomously exchanges session information between smart posters in this paper. Moreover, the smart poster based on Raspberry was implemented to verify validity of this protocol, and an experiment was conducted to measure the request and response time between smart posters in the implemented environment. In the experiment, when the other poster sent the message requesting the exercise session 100 times and received the response message, the 95 percentage of received messages had the response time within 0.05 seconds.