• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.1C
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• pp.21-35
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• 2002

Nowadays, in accordance with increasing expectations of multimedia stream service on the internet, a lot of distributed applications are being required and developed. But the models of the existing systems have the problems that cannot support the extensibility and the reusability, when the QoS relating functions are being developed as an integrated modules which are suited on the centralized controlled specific-purpose application services. To cope with these problems, it is suggested in this paper to a distributed QoS management system on CORBA, an object-oriented middleware compliance. This systems we suggested can provides not only for efficient control of resources, various service QoS, and QoS control functions as the existing functions, but also QoS control real-time negotiation and dynamic adaptation in addition. This system consists of QoS Control Management Module(QoS CMM) in client side and QoS Management Module(QoS MM) in server side, respectively. These distributed modules are interfacing with each other via CORBA on different systems for distributed QoS management while serving distributed streaming applications. In phase of design of our system, we use UML(Unified Modeling Language) for designing each component in modules, their method calls and various detailed functions for controlling QoS of stream services. For implementation of our system, we used OrbixWeb 3.1c following CORBA specification on Solaris 2.5/2.7, Java language, Java Media Framework API 2.0 beta2, Mini-SQL 1.0.16 and the multimedia equipments, such as SunVideoPlus/Sun Video capture board and Sun Camera. Finally, we showed a numerical data controlled by real-time negotiation and adaptation procedures based on QoS map information to GUIs on client and server dynamically, while our distributed QoS management system is executing a given streaming service.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 1996.06b
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• pp.95-100
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• 1996

User's qualities of services (QoS) are the basic requirements involved in distributed multimedia systems. Considering ATM network, ATM adapter cannot control the end-to-end connection satisfying the user's QoS. This paper describes the new concept of a QoS prediction management system in the distributed network and the configuration of it's QoS prediction management architecture and also discusses it's algorithm.

• Journal of the Korea Society of Computer and Information
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• v.12 no.6
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• pp.1-9
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• 2007

We propose a novel framework for distributed resource management. The framework has the following novel features. First, the resource management system is distributed using resource content information that is characterized by system properties. We argue that a distributed system based on resource content is sufficient to satisfy specific scheduling requests for Quality of Service(QoS) considering workload balance across a grid. Second, the distributed system constructs a hierarchical peer-to-peer network. This peered network provides an efficient message routing mechanism. The simulation results demonstrate that the proposed framework is proficient to satisfy QoS in distributed environment.

• Journal of Digital Contents Society
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• v.4 no.2
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• pp.181-189
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• 2003

The requirement of distributed multimedia applications is the need for sophisticated QoS(quality of service) management. In terms of distributed multimedia systems, the most important catagories for quality of service are a timeless, volume, and reliability In this paper, we discuss a method for increasing reliability through fault tolerance. We describe the design and implementation of the ECA running on distributed multimedia environment. ECA is a system is able to classify automatically a software error based on distributed multimedia. This papaer explains a performance analysis of an error classification system running on distributed multimedia environment using the rule-based DEVS modeling and simulation techniques. In DEVS, a system has a time base, inputs, states, outputs, and functions.

• Proceedings of the KAIS Fall Conference
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• 2009.12a
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• pp.461-465
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• 2009

Normally, a distributed computing environment is flexible in controlling complex embedded systems but their software components are becoming complex as these systems are equipped with several platforms and attached to various electronic devices, sensors, and actuators. These systems requires inter-object communication mechanisms to provide fault tolerant and QoS-enabled middleware service support in a distributed system. Generally, a middleware performs analysis of the parameters to ensure the availability and reliability of data dissemination. This paper focuses in particular to designing an application middleware for the specific scenario to improve the high availability and fault tolerance of data thus improving the QoS (Quality of Service) of a distributed system. The performance of an adaptive and highly reliable middleware can be significant based on the selection of vital parameters of the system.

• Journal of Digital Contents Society
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• v.6 no.1
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• pp.85-88
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• 2005

The requirement of distributed multimedia applications is the need for sophisticated QoS(quality of service) management. In terms of distributed multimedia systems, the most important catagories for quality of service are a timeless, volume, and reliability. In this paper, we discuss a method for increasing reliability through fault tolerance. We describe the desist and implementation of the ERA running on distributed multimedia environment ERA is a system is able to recover automatically a software error based on distributed multimedia. This paper explains a performance analysis of an error recovery system running on distributed multimedia environment using the rule-based DEVS modeling and simulation techniques. In DEVS, a system has a time base, inputs, states, outputs, and functions.

• The KIPS Transactions:PartA
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• v.15A no.2
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• pp.101-110
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• 2008

Ubiquitous computing has extended the computer system into the whole physical space and has ushered the emergence of more dynamic distributed systems. This environment require unique QoS parameters for various devices, resources and user requirements. In this paper, we propose a new hybrid QoS management model which defines a static-dynamic QoS parameter that is more appropriate to the ubiquitous computing environment. This model consists of the QoS Control Management Module(QoS CMM) in the client side and the Resource QoS Management Module (RQoS MM) in the server side. The RQoS MM deals with the static QoS parameters and the whole QoS control of the distributed control(QoS CMM) in order to minimize server load in cases of multiple communication. Finally, we present the experimental result of our location based application using a graphical user interface that shows the multimedia service execution of selected client device types such as desktop PC, notebook and PDA.

• Journal of KIISE:Computer Systems and Theory
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• v.30 no.11
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• pp.675-690
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• 2003

In this paper, we present the virtual dancing studio for distributed virtual environment. In this system, geographically distributed user shares the virtual dancing hall and interacts with each other. The participating object can be a graphical avatar or a live video stream. It allows the coexistence of graphic objects and real images in the shared virtual space. One of the main technical challenges in developing the distributed virtual environment is to handle excessive network traffic. In an effort to effectively reduce the network traffic, we propose a scheme to adjust the QoS of each object with respect to the distance from the observer in the virtual space. The server maintains the QoS vector for each client's shared space and controls the packet traffic to individual clients based on its QoS vectors. We develop a proto-type virtual dancing environment. Java based development enables the client to be platform independent. The result of experiment shows that the adoption of hierarchical QoS management significantly reduces the overall network traffic.

• Journal of Korean Society for Quality Management
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• v.39 no.3
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• pp.412-421
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• 2011

In this paper, we introduce Quality of Service(QoS) analytic model of a distributed system that decentralizes the process nodes performing each task and communicates through a network for cooperation. The model advances a service reliability model of Dai et a1.(2003) by means of considering the processing time. The service is assumed to be provided by a centralized heterogeneous distributed system which is composed of some subsystems managed by a control center. The QoS is defined as the probability that a service is provided successfully in an allowed time, we consider the hardware/software reliability and the processing time which include program execution time, data transfer time. We derive the processing time distribution for a required service through convolution of corresponding probability density function. An application example is used to explain the procedure of computing quality of service.

• ETRI Journal
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• v.28 no.1
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• pp.31-44
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• 2006

In a packet switching network, congestion is unavoidable and affects the quality of real-time traffic with such problems as delay and packet loss. Packet fair queuing (PFQ) algorithms are well-known solutions for quality-of-service (QoS) guarantee by packet scheduling. Our approach is different from previous algorithms in that it uses hardware time achieved by sampling a counter triggered by a periodic clock signal. This clock signal can be provided to all the modules of a routing system to get synchronization. In this architecture, a variant of the PFQ algorithm, called digitized delay queuing (DDQ), can be distributed on many line interface modules. We derive the delay bounds in a single processor system and in a distributed architecture. The definition of traffic contribution improves the simplicity of the mathematical models. The effect of different time between modules in a distributed architecture is the key idea for understanding the delay behavior of a routing system. The number of bins required for the DDQ algorithm is also derived to make the system configuration clear. The analytical models developed in this paper form the basis of improvement and application to a combined input and output queuing (CIOQ) router architecture for a higher speed QoS network.