• Journal of Digital Contents Society
• /
• v.3 no.2
• /
• pp.255-264
• /
• 2002

Multimedia is now applied to various real worlds. In particular, the focus of CSCW(Computer Supported Cooperated Work) for multimedia education system has increased. DOORAE is a framework for supporting development of applications running on distributed multimedia environment and multimedia distance education system. EDA is a system is able to detect automatically a software error based on distributed multimedia. It has been designed and implemented for construction and experiment of effective DOORAE environment. It detects an error by polling periodically the process with relation to session. Conventional method detects an error by polling periodically all the process. This papaer explains a performance analysis of an error detection system running on distributed multimedia environment using the rule-based SES and DEVS modeling and simulation techniques. In DEVS, a system has a time base, inputs, states, outputs, and functions.

• Journal of Korea Multimedia Society
• /
• v.13 no.7
• /
• pp.1016-1022
• /
• 2010

Far-talking recognition and distributed speech recognition networking techniques are essential to control various and complex home services conveniently with voices. It is possible to control devices everywhere at home by using only voices. In this paper, we have developed the server-client DSP module for distributed speech recognition network system and proposed a new decision rule to decide intelligently whether to accept the recognition results or not by the transferred confidence rate. Simulation results show that the proposed decision rule delivers better performances than the conventional decision by majority rule or decision by first-arrival. Also, we have proposed the new interrupt-polling technique to remedy the defect of existing delay technique which always has to wait several clients' results for a few seconds. The proposed technique queries all client's status after first-arrival and decides whether to wait or not. It can remove unnecessary delay-time without any performance degradation.

• Journal of the Institute of Electronics Engineers of Korea SC
• /
• v.47 no.3
• /
• pp.1-4
• /
• 2010

RS-485, communication bases from small network system must prepare in collision. The collision is that mean the data transfer breaks. For a stabilized communication chooses 1:N polling methods. But polling is low speed in addition to maybe overload Master device. So, usual N:N Prefers a communication. In this case, must be preparing to avoid collision or some solutions. Generally, to after collision retransmits after short time. It's called delay time for short time. When making a delay time, uses address of each systems. (Address of each node) If the many nodes collided, the each node has different delay time. When making a delay time, uses a usual random number. Making a random number is hard job. So uses a usual pseudorandom number. It is more difficult from small size MCU. The Chaos random number provides stabled value. Finally, when uses the Chaos random number, the stability and reliability of system get better.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.41 no.7
• /
• pp.31-40
• /
• 2004

In this paper, we analyze mathematically the performance of the gated service scheduling in the Interleaved Polling with Adaptive Cycle Time(IPACT) was proposed to control upstream traffic for Gigabit Ethernet-PONs. In the analysis, we model EPON MAC protocol as a polling system and use mean value analysis. We divide arrival rate λ into three regions and analyze each region accordingly In the first region in which λ value is very small, there are very few ONUs' data to be transmitted. In the second region in which λ has reasonably large value, ONUs have enough data for continuous transmission. In the third region, ONUs' buffers are always saturated with data since λ value is very large. We obtain average packet delay, average Queue size, average cycle time of the gated service. We compare analysis results with simulation to verify the accuracy of the mathematical analysis. Simulation requires much time and effort to evaluate the performance of EPONs. On the other hand, mathematical analysis can be widely used in the design of EPON systems because system designers can obtain various performance results rapidly. We can design appropriate EPON systems for varioustraffic property by adjusting control parameters.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
• /
• 2013.04a
• /
• pp.146-147
• /
• 2013

최근 건축물이 대형화, 복잡화, 초고층화가 되어감에 따라 건축물의 변화에 대해 발생하고 있는 재난 재해는 더욱 다양해지고 대형화되어 가고 있다. 이러한 건축물의 변화에 대해 소방시설은 통합네트워크시스템을 구축하고 있으나, 우리나라와 미국은 시스템은 개별업체가 하고 있지만 수신기의 상호 시스템통합은 협의하지 않고 독립적이며 일본은 공업회에서 전용프로토콜을 사용하고 있었다. 수신기와의 상호 신호 전송방식은 Polling Addressing/RS-485과 P-MAST Polling Addressing이었다. 타 시스템과의 신호 상호연동은 3개사 모두 Ethernet 연결하고 있었으나 2개사는 광변환장치를 사용하였고 1개사는 Ethernet를 사용하였다.

• Journal of Communications and Networks
• /
• v.11 no.1
• /
• pp.36-41
• /
• 2009

The IEEE 802.16 wireless metropolitan area network (WMAN) standard is designed to correct expensive communication costs in CDMA-based mobile communication systems and limited coverage problems in wireless LAN systems. Thus, the IEEE 802.16e standard can provide mobile high-speed packet access between mobile stations and the Internet service provider through the base station with cheap communication fees. To efficiently accommodate voice over IP (VoIP) services in IEEE 802.16 systems, an uplink quality of service packet-scheduling scheme is proposed, and its performance is evaluated with an NS-2 network simulator in this paper. Numerical results show that this proposed scheme can increase the system capacity by 100% more than in the unsolicited rand service (UGS) scheme and 30% more than the extended real-time polling service (ertPS) scheme, respectively.

• 제어로봇시스템학회:학술대회논문집
• /
• 2000.10a
• /
• pp.48-48
• /
• 2000

We developed a wireless communication system for multiple instrumentation system. The developed system has a function of remote instrumentation and PLC(Programmable Logic Controller) control. The system consists of CC(Control and Communication) protocol, wireless media access and physical media system. For multiple wireless communication, we propose a hub polling protocol based on master-slave control concept. To show the validity of the developed system, several experiments are illustrated.

• Journal of Korean Society of Transportation
• /
• v.22 no.6
• /
• pp.77-88
• /
• 2004

This study aims at developing the model that is able to detect the compression wave, which is included as a similar situation in incidents, that causes false applicable to the similar character such as incidents in the incident detection model for expressways. In this study, it has been checked whether the number of false alarms is decreased or not by modularizing this model for being able to applicable to other models such as DES and DELOS, etc. which do not perform the compression wave test based on the compression wave test process of APID model which has been being used in the expressway traffic management system currently. The evaluation in this study focuses on the sensitivity of the model and the results analysis is performed classified by each polling cycle. And how well these models are working is evaluated by each polling cycle. In addition to this, the detection rate, the false alarm rate and the average detection time in both the existing models and the model in this study are calcuated. As a result of appling the model in this study, it is found that the false alarm rate is improved through the reasonable decrease in the number of false alarm frequencies and there are not remarkable changes concerning the detection rate and the average detection time. To sum up, it is expected that a good number of improvement effects will be occurred when this model is applied to the actual expressway traffic management system.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.33 no.9B
• /
• pp.813-821
• /
• 2008

In recent year, several types of PON(Passive Optical Networks) have been adopted into the subscriber loops for the high speed subscriber lines to meet the needs of some applications based on the Internet and the rapid increase of the Internet users. GPON(Gigabit PON) is a typical access network technology of these PONs which adopt the DBA(Dynamic bandwidth Allocation) scheme in order to transmit upstream traffic efficiently. In this paper, we introduce the gated polling system with a two-stage queue in order to analyze the delay performance of the DBA scheme in a GPON. We use a continuous time queueing model for deriving the mean cycle time and for obtaining the mean packet delay. We give some numerical results to investigate the delay performance for the symmetric polling system with statistically identical stations.

• 제어로봇시스템학회:학술대회논문집
• /
• 1996.10b
• /
• pp.1420-1423
• /
• 1996

This paper presents the implementation of network for automation using fieldbus. The RS-485 and twisted pair are used in layer 1 and medium, respectively. We implement FDL(Fieldbus Datalink Layer) using C-language and use token-bus network. The network consists of polling system and token passing system. The amount of transmitted data frames is evaluated with various transmission speeds that affect the system stability.