• Proceedings of the Acoustical Society of Korea Conference
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• spring
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• pp.221-224
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• 2002

VoIP 음성 통신 시스템에서 통화를 할 때, 네트워크 상황이 나빠짐에 따라 시간 지연, 패킷 손실, 지터 등의 QoS 파라미터에 의한 영향이 발생하므로 통화 품질이 떨어지게 된다 통화 품질을 개선하기 위해서는 통화 품질과 QoS 파라미터와의 관계를 명확히 파악하고 그에 대한 개선 방법을 연구해야 한다. 따라서 본 논문에서는 통화 품질과 QoS 파라미터와의 상관관계를 회귀 분석을 통해 도출해 내었다. 제시된 음질 평가 기준은 QoS 파라미터만을 가지고 음질을 예측하기 때문에 계산량이 매우 적으며, 음질 평가 수행 중에 음성 통신 시스템에 거의 영향을 미치지 않는다는 장점을 가지고 있다.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.42 no.12
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• pp.17-24
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• 2005

Traditional Internet applications such as FIP and E-mail are increasingly sharing bandwidth with newer, more demanding applications such as Web browsing, IP telephony, video conference and online games. These new applications require Quality of Service (QoS), in terms of delay, loss and throughput that are different from QoS requirements of traditional applications. Unfortunately, current Active Queue Management (AQM) approaches offer monolithic best-effort service to all Internet applications regardless of the current QoS requirements. This paper proposes and evaluates a new AQM technique, called MCDT that provides dynamic and separated buffer threshold for each Applications, those are FTP and e-mail on TCP traffic, streaming services on tagged UDP traffic, and the other services on untagged UDP traffic. Using a new QoS metric, our simulations demonstrate that MCDT yields higher QoS in terms of the delay variation and a packet loss than RED when there are heavy UDP traffics that include streaming applications and data applications. MCDT fits the current best-effort Internet environment without high complexity.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38C no.3
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• pp.327-333
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• 2013

In this paper, we propose a QoS information collection method at the information server in maritime networks with multi-network interfaces, and a route selection scheme based of the measured predictive QoS information comparing with parameters requested from a mobile node in a ship entering into a harbor from near-shore area. By changing network conditions and applying various application bandwidths, we check the operation of our proposed scheme and measure its performance of the original and proposed schemes in the viewpoints of the received packet traffic and end-to-end delays.

• Journal of Information Technology Applications and Management
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• v.12 no.3
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• pp.129-150
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• 2005

Due to the advance of the Internet, the electronic commerce is getting more widely used, and customer's demand for the e-Commerce service quality is rapidly increasing. On the other hand, e-Commerce companies required the Internet services whose quality is provided more reliable service to their customers. Therefore, it is very important to provide both e-Commerce companies and customers with the measurement and service quality in real-life network environment. But the research on the service quality measurement method for electronic commerce systems has been limited because ISP and e-Commerce providers seldom disclose detailed service measures such as, where and how much service delay incurred. In this paper, we construct sample e-Commerce systems and try to measure the service quality of the systems in real network environment. We have analyzed the delay zones and causes using a measurement tool. We must reflect the improvement method against delay causes. Accordingly, the customers can be experiences the better service quality. We hope that this research will be the groundwork for future research on the service quality of various types of e-Commerce systems and online services.

• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.4
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• pp.491-498
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• 2014

As internet services are being provided through a wireless access, the importance of quality of experience (QoE) is stressed that is defined as the quality that indicates user's actual feeling when a service is provided. Unlike quality of service (QoS) that can be expressed as a numerical value, it is difficult to represent QoE in an objective way. If an internet service is serviced over a wireless channel, its QoE can be affected by a number of factors such as fading, mobility and so on. This paper, therefore, attempts to specify the relationship between QoE and QoS by conducting practical measurements for the voice service through 3G high speed packet access (HSPA) access network. Analysing the measured results, it has been shown that received signal strength indicator (RSSI) has a great influence on mean opinion score (MOS) through transmission delay.

• The Journal of Information Technology
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• v.12 no.3
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• pp.49-57
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• 2009

This Paper provides perceptual metrics for video quality based on properties of human visual system, and audio quality based on human audition. All metrics work without reference signals, allowing non-intrusive, in-service measurements. A simple and easy-to-learn user interface displays the metrics and saves them in popular file formats like CSV. In this paper, proposed method was able to various and corrective measurement for the multimedia service video quality. As that it was able to application to set up service guide line and the methode of measurement and system for the set up standardization of the high quality video service.

• Journal of Digital Contents Society
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• v.13 no.4
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• pp.625-629
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• 2012

This paper is presented to prepare NGN quality assurance management process under the quality system test methodology. The process should be drawn for NGN quality measurement framework of multimedia traffic. NGN test bed management process model are QoS measurement metrics, measurement interval meter above, and measuring tools, measuring equipment, measurement methods and measurement results from a series of processes for the analysis and methodology. This model, NGN quality assurance activities should be utilized in the future. Quality target level only when themselves constantly measured and managed, does not guarantee the communication quality of service. It is sensitive to the importance of NGN network technology paradigm for research on quality management in the NGN.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.1
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• pp.149-154
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• 2014

Quality is the value that can be measured by observing the characteristics of the service quantity or quality. QoS is predictable service traffic to a minimum requirements what passed in network. In the course of Smart Medical Information System Development there exist some functional requirements to satisfy quality objectives. The functional smart domains of healthcare information systems consists of Patient Module, a smart sensing and communication domain, RFID Tag Readers and the behavior domain, Homecare Station Domain, Clinical Station. This study is performed on evaluation methodology of u-health service satisfaction quality of each domain. In this paper QoS metrics and the quality of medical information requirements, functional requirements are separated by. Quality parameters consists of six items and the functional requirements and quality requirements 20 details the five items and consist of 20 detailed items. On this study the quality evaluation methodology of Korean smart health information quality assessment matrix 2 - factor evaluation method is proposed. The overall framework of this paper is organizing the specific criteria of quality of medical information system and modeling quality evaluation process under all smart environment.

• The KIPS Transactions:PartC
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• v.18C no.1
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• pp.23-30
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• 2011

Recently internet protocol television (IPTV) service is becoming a typical emerging service enabled on broadband networks. Through the Internet which cannot support quality of service (QoS) beyond best-effort (BE) policy, how to manage and maintain its service quality is an important and essential issue for successful deployment and settlement of IPTV service. In particular, the current measurement scheme that mostly depends on specific equipments should be replaced with one that supports realtime and constant measurement achieved on a user's own will. Therefore, this paper proposes a scheme so-called 'user centric realtime measurement' of IPTV service. The developed software, which is installed in a set-top box (STB) at a user's premise, measures and reports the quality of IPTV service in realtime. In order to verify the performance and accuracy of the developed software, a number of tests are performed comparing to the measurement values from two major measurement equipments. The result of the tests shows that the measurement by the implemented software is significantly reliable.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2005.05a
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• pp.1083-1088
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• 2005

통신서비스의 QoS에 대한 관심이 증가하면서 서비스품질보증협약(SLA)의 중요성도 증대하고 있다. 통신사업자는 기업 사용자들의 QoS에 대한 요구수준을 만족시켜 주기 위해서 SLA의 제공을 확대하고 있으나, 여전히 통신사업자의 입장에서 SLA의 제공 내용을 설계하는 경향이 있다. SLA의 제공을 통해 달성하고자 하는 목적이 기업 사용자들의 통신서비스에 대한 서비스품질의 개선과 이를 통한 로열티 개선에 있다고 하면 이와 같은 접근과 시도는 앞으로 개선되어야 할 것으로 판단된다. 이와 같은 문제점을 극복하기 위해서 SLA의 제공과 관련, 기업 사용자에 대한 설문조사를 통해 요구사항과 개선방향을 파악해 보는 것은 현재 시점에서 SLA 제공 과정에서 적절한 시도라고 판단된다. 이에 본 논문에서는 SLA 제공과정에서 통신사업자가 고려해야 하는 사항에 대해 주로 서비스품질보증항목 (SLO), 측정(Measurement), 보상(Penalty) 등 SLA의 주요 구성요소 와 차세대 네트워크의 구축에 따라 향후 추가적으로 요구될 수 있는 요소들에 대해 점검해 보고자 한다. 이를 통해 QoS 보장에 대한 가장 유용한 도구로서의 SLA 제공의 활용성과 극대화를 기대해 본다.