• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.9A
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• pp.736-745
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• 2003

Resource allocation methods are proposed to address the problem of how flexibly allocate limited wireless resource to high bandwidth demanded realtime class with certain QoS guarantees in CDMA/TDD systems. In this method, A reserved access scheme is used for allocating the resource to realtime and non-realtime class respectively. We also propose a slot allocation algorithm for the CDMA/TDD system, which can prevent the performance degradation due to the interlink interference in each cell. Our framework is able to guarantee QoS continuity of realtime class and carry the maximum number of non-realtime subscriber. System performance of proposed method is evaluated by considering transmission delay, channel utilization and data loss, assuming a practical multi-cell environment and a multimedia service model. Our simulation results demonstrate the significant performance improvement.

• Journal of Scientific & Technological Knowledge Infrastructure
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• s.4
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• pp.80-93
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• 2001

본 고에서는 멀티미디어 서비스를 위한 인터넷 QoS(Quality of Service) 기술요소를 살펴보았다. 즉 Intserv/RSVP 기반의 플로우 단위의 품질보장기술, Diffserv에 의한 CoS(class of service) 기술, SBM과 같은 대역폭관리기술 등을 살펴보고 이들 요소기술이 조합된 예를 살펴보았다. 또한 차세대 인터넷에서의 SLS(Service Level Specification)를 고찰했다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.11B
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• pp.891-899
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• 2004

Ethernet passive optical network (EPON) has drawn many attention as a promising access network technology because it can provide a high bandwidth with a low cost. Since the uplink in the EPON system is shared by many users, it is necessary for an EPON system to have an efficient bandwidth allocation mechanism. In addition, as the users demand more QoS-oriented applications, it is necessary for an EPON system to have an efficient mechanism supporting QoS. In this paper, we propose a variable window dynamic bandwidth allocation (DBA) algorithm for the EPON system. Unlike the previously proposed DBA algorithms, the variable window algorithm guarantees the QoS for the highest priority class, and at the same time provides more enhanced QoS for the lower priority classes by dynamically allocating bandwidth if necessary. It is verified through the simulations that the variable window algorithm can provide more enhanced QoS performance than other DBA algorithms.

• Proceedings of the Korea Information Processing Society Conference
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• 2004.05a
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• pp.1307-1310
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• 2004

네트웍이 고속화 됨에 따라 대용량 데이터를 실시간으로 전송/처리/저장하는 응용 분야가 등장하고 있다. 또한 전송 지연을 감소하고 신뢰도를 향상하기 위해서 많은 스토리지(storage) replica들이 네트웍에 설치되었다. 이러한 환경에서 응용 프로그램이 요구하는 성능을 만족하기 위해서는 네트웍 자원 뿐만 아니라 종단간 자원인 저장 매체의 선택/예약/관리를 함께 고려하는 통합적 분산 네트웍 스토리지(DNS: Distributed Network Storage) 시스템이 필요하다. 이러한 DNS에서 QoS를 제공하는 기존의 방식들은 크게 데이터그램(datagram) QoS, 클래스(class)별 차등적인 서비스를 제공하는 DiffServ QoS, 그리고 각 플로우(flow) 별 개별적인 서비스를 제공하는 IntServ QoS로 세분된다. 본 논문에서는 기존에 제안된 방식들을 비교 분석하여 각각의 장단점을 기술하며 향후 연구 문제들을 살펴본다.

• Journal of IKEEE
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• v.5 no.2 s.9
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• pp.136-145
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• 2001

As with appearing new applications that requires QoS guarantee such as VoIP, VPN in Internet, problems of IP QoS has been one of most important issues in next-generation Internet. IETF has proposed integrated services model(Int-Serv) and differentiated service(Diff-Serv) to supply IP QoS in Internet. Int-Serv model uses the state information of each IP flow, so satisfies QoS according to traffic characteristics, but increases the amount of flow state information with increasing flow number. Diff-Serv model uses PHP(Per Hop Behavior), and there are well-defined classes to provide differentiated traffics with different services according to delay and loss sensitivity. Diff-Serv model can provide diverse services in Internet because of having no the state and signal information of each flow. As MPLS uses the packet forwarding technique based-on label, it implements the traffic engineering in the networks easily. The MPLS can set up the path with different traffic parameters, and assign each path to particular Class of Services. Therefore it is possible to support the Diff-Serv model with well-defined classes. In this paper we investigate the performance improvement of Diff-Serv function in the MPLS network to guarantee class of services in Internet.

• Proceedings of the Korean Information Science Society Conference
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• 2004.10c
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• pp.547-549
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• 2004

본 논문에서는 IP/MPLS 망에서 QoS 보장형 차별화 서비스 제공을 위한 Virtual Networking 구조를 제안한다. 제안한 구조에서는 멀티미디어 단말장치와 PE(Provider Edge) 사이에서 RSVP-TE를 이용한 signalling을 통해 연결설정을 요청하고 PE에서 CAC(Call Admission Control)가 이루어질 수 있도록 한다. 또한 provider network에서 일반 가입자에게 QoS 보장형 차별화 서비스를 제공해줄 수 있도록 Multiple Virtual Network을 구성하며, class-type별로 차별화된 virtual network을 구성하기 위해서 L-LSP를 PE간에 full-mesh 형태로 설정한다 본 논문에서 제안한 Virtual Networking을 통하며 망 사업자는 보다 효율적으로 망을 관리하며, 통신망 자원의 이용율을 극대화시키고 사용자들에게 QoS 보장형 차별화 서비스를 제공해주는 것이 가능하다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.9A
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• pp.762-771
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• 2005

In this paper, an efficient Adaptive quality-of-service (QoS) traffic control scheme with priority scheduling is proposed for the multimedia traffic transmission over wireless access networks. The objective of the proposed adaptive QoS control (AQC) scheme is to realize end-to-end QoS, to be scalable without the excess signaling process, and to adapt dynamically to the network traffic state according to traffic flow characteristics. Here, the reservation scheme can be used over the wireless access network in order to get the per-flow guarantees necessary for implementation of some kinds of multimedia applications. The AQC model is based on both differentiated service model with different lier hop behaviors and priority scheduling one. It consists of several various routers, access points, and bandwidth broker and adopts the IEEE 802.1 le wireless radio technique for wireless access interface. The AQC scheme includes queue management and packet scheduler to transmit class-based packets with different per hop behaviors (PHBs). Simulation results demonstrate effectiveness of the proposed AQC scheme.

• Journal of the Korea Society for Simulation
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• v.14 no.1
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• pp.33-42
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• 2005

Service Level Agreement (SLA) is a service providing scheme by a service class agreement between a user and a service provider SLA allows that a user can select an expected service class in various service classes provided from a service provider. Recently, SLA management is adapted to support the end-to-end Qos for service users in Beyond 3 Generation (B3G) networks. In B3G networks, SLA provides multiple service classes on access networks so that service classes should be managed to assure the service satisfaction for users. In this paper, we propose a dynamic Qos management scheme by IP traffic class controlling based on SLA in B3G networks. Also, to manage dynamic traffic service, we consider Differentiated services (Diffserv) mechanism for the resource management by SLA. An If service traffic class on SLA can be dynamically changed by Diffserv traffic management to support dynamic end-to-end Qos. Hence, in this paper, we consider the buffer threshold scheme for controlling traffic loads and the traffic level control scheme for implementing the dynamic traffic management by the SLA.

• Research in Community and Public Health Nursing
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• v.31 no.2
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• pp.212-221
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• 2020

Purpose: This study aims to identify the types of health-related quality of life (QoL) based on the EuroQoL 5 Dimensions among community older people and predict the factors affecting these types. Methods: This study used data from the 2016 Korea Health Panel Survey, whose participants included 3,848 older people. The data were analyzed using the software jamovi 1.2.17 and Mplus 8.2 for latent class analysis. Results: The subgroups of the older people's health-related QoL were identified as three latent classes: General stable type (43.9%), pain-related low type (35.0%), and general low type (21.1%). The types and characteristics of health-related QoL among the latent classes differed. Comparing the difference between the general low type and general stable type, the subjects showed higher probability of belonging to the general stable type when they were men, younger, higher education level, employment, better subjective health, lower BMI and stress level, and no suicidal ideation. A comparison between the general low type and the pain-related low type showed that the subjects were more likely to be classified as the pain-related low type when they were younger, higher education, employment, and better subjective health. Conclusion: The results showed a significant heterogeneity in the types of health-related QoL among community older people, and the predictors for each type were not the same. These findings present basic data for cultivating nursing interventions that enhance health-related QoL.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.2C
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• pp.131-142
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• 2002

It is Proposed thatthe Algorithm for Self healing to restoration the backup VP Occurrence Error in ATM Network. This study focuses on self-healing algorithm to restore failed VP. and backup-VP algorithm, one of the popular self-healing algorithm, is applied in this study. The problem with the existing algorithm is that when backup-VP is failed, there is no solution. This study proposes backup-VP algorithm to guarantee QoS in accordance with class. This study evaluates the effect of failure and proposes two algorithms. One is a disjointed path group to node pair class, and the other is one that applied different backup-VP case by case. Through simulation network restoring ability is compared, analyzed and synthesized.