• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.9 no.6
• /
• pp.151-158
• /
• 2010

In line with the requirement of appropriate protocol support for such mission-critical wireless sensor network (WSN) applications as patient monitoring, we investigate the framework for designing medium access control (MAC) schemes. The data traffic in medical systems comes with inherent traffic heterogeneity as well as strict requirement of reliability according to the varied extents of devise-wise criticality in separate cases. This implies that the quality-of-Service (QoS) issues are very distinctly delicate requiring specialized consideration. Besides, there are features in such systems that can be exploited during the design of a MAC scheme. In a monitoring or routine surveillance application, there are degrees of regularity or predictability in traffic as coordinated from a node of central control. The coordinator thus takes on the role of marshaling the resources in a neighborhood of nodes deployed mostly for upstream traffic; in a collision-free scheme, it schedules the time slots for each superframe based on the QoS specifications. In this preliminary study, we identify the key artifacts of such a MAC scheme. We also present basic performance issues like the impact of superframe length on delay incurred, energy efficiency achieved in the network operation as obtained in a typical simulation setup based on this framework.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.27 no.1C
• /
• pp.11-20
• /
• 2002

In this paper, we propose an efficient quality providing scheme to satisfy a diversify combination of delay bound and loss ratio requirements from users by a predictive dynamic resource allocation method for real-time video applications. For utilizing the network resources more efficiently while meeting the service requirements, we adjust the resources based on the predicted traffic and the currently provided quality level. We developed a simple delayed-packet counter updating scheme for real time QoS monitoring. Simulation results show that our proposed method can provide an accurate and flexible quality control.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.13 no.5
• /
• pp.101-105
• /
• 2013

This paper addresses QoS functions in mobile backhaul network to accommodate the diverse traffics in cell site. The traffics assigned to the switching function in RAN system, such as Ethernet frame, IP packet, and ATM cell, are segmented, and then encapsulated to transfer then to the mobile backhaul network. ISP can converge all generation traffics, such as voice, HSPA, over all-IP RAN through standard pseudowire encapsulation. These can be enhanced with diverse QoS methods as well as comprehensive monitoring and diagnostic capabilities. Therefore in this paper, QoS functions under theses operations is simulated according to the encapsulation functions.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.32 no.2B
• /
• pp.133-142
• /
• 2007

WPANs are formed in relatively small area and a PNC that serves as a central control device plays an important role in the operation and organization of a piconet. Typical applications of WPANs are security system and health monitoring system. In these type of systems, guaranteeing realtime service is very important, and communications cannot take place when the PNC malfunctions. Thus, in this situation, it is necessary to elect a new PNC as soon as possible. For this reason, we propose distributed PNC election scheme that considers not only QoS support but also network connectivity to avoid possible network partition. Simulation results show proposed mechanism can select PNC with guaranteeing QoS and connectivity for a limited period.

• Journal of KIISE:Computing Practices and Letters
• /
• v.5 no.5
• /
• pp.619-627
• /
• 1999

To support multimedia services between network domains with different environments, it is required to map the functionalities in many aspects. In this paper, we implemented interworking gateway which provides protocol conversion and QoS(Quality of Service) adaptation to interwork DAVIC services based on ATM(Asynchronous TRansfer Model )network and Internet AV services. The interworking gateway converts RTSP(Real-Time Streaming Protocol ) message into DSM-CC(Digital Storage Media Command & Control) messages to control the stream that is served in ATM network, and transmits data stream by using RTP(Real-Time Transport Protocol) The interworking gateway provides QoS adaptation functionalities by QoS monitoring and MPEG filtering to meet the variation of network bandwidth.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.15 no.4
• /
• pp.2393-2398
• /
• 2014

Because each resource in LTE-Advanced system and network's shapes such as bandwidth, error rate change variably, it is judged that it is impossible to control service continuity with procedural, artificial, and static control method applied to the existing voice service. This research suggests a QoS management mechanism to support the service continuity effectively based on policy control. It means a method in which a subscriber's terminal collects information about its current condition and base station around, and a base station, through the data collected by monitoring inner or adjacent base station, shares related data and converges, controlling service continuity on its own.

• Proceedings of the Korean Information Science Society Conference
• /
• 2003.10c
• /
• pp.103-105
• /
• 2003

그리드 환경에서 효율적인 자원할당과 QoS를 보장하기 위해서는 먼저 각 자원의 사용가능한 정도를 정확히 파악하여야 한다. 본 논문은 정확한 자원을 측정하기 위한 리소스 모니터링 시스템을 제안하였다. 그리드에서의 모니터링 시스템은 기존의 모니터링 시스템과 차별화 되어있기 때문에 GGF(Global Grid Forum)에서 제안한 자원 측정 요구사항을 수용하여 구현하였다.

• Proceedings of the Korean Information Science Society Conference
• /
• 2004.04a
• /
• pp.103-105
• /
• 2004

본 논문에서는 프로세스 모니터링 기법에 기반한 DVS 시스템을 제안한다. 이상적인 DVS 시스템은 응용프로그램의 수정 없이 자동으로 수행되어야 하며 프로세스의 QoS를 고려해야 한다. 본 논문은 이를 위해 본 연구의 이전 논문에서 제시한 Kernel Control Path를 모니터링하여 주기적 프로세스의 QoS관련 정보를 추출할 수 있는 기법을 기반으로 DVS 시스템을 제안한다. 제안한 DVS 시스템은 리눅스 운영체제상에서 실제 구현하였으며 관련 연구와의 비교를 위해 관련연구도 구현하여 실험하였다. 이를 통해 제안한 DVS 시스템이 주기적 프로세스의 QoS를 보장하면서 전력소비를 최소화할 수 있음을 밝힌다.

• Journal of The Korean Society For Urban Railway
• /
• v.6 no.4
• /
• pp.351-361
• /
• 2018

In this paper, we analyse DDS(Data Distribution Service) QoSs(Quality of Services) with experiments, which can control the network transmission quality provided by 'Object Management Group' DDS standard to satisfy the data transmission quality requirements of 'Real-time integrated railway safety monitoring and control system(RIRSMCS)'. 'RIRSMCS' is a system for collecting and analyzing data from various sensors at a railway field to predict and prevent the risk of potential railway accidents. Data transmission quality should be ensured for transmitting the collected data in real-time, accurately and stably for this system. Experimental results show that it is possible to ensure real-time, accurate and stable data transmission for monitoring and control of railway safety using DDS QoS.

• Proceedings of the IEEK Conference
• /
• 2001.06c
• /
• pp.97-100
• /
• 2001

A common network such as internet does not provide a guaranteed network bandwidth to accommodate multimedia service in a reliable fashion. In this paper, we propose a new rate control mechanism for multimedia service on the internet which is adaptive to the dynamic QoS in real-time. Also we adapt an QoS monitoring module and real-time transmission control module to adapt dynamic network bandwidth. To do this, we used layer attribution of media data and also considered loss rate and buffer threshold in receiver side for measurement of dynamic QoS.