IEEE 802.11b/g 무선랜 기반 SOHO환경에서의 트래픽 측정 및 분석

정우철,김성수,송왕철 제주대학교 공과대학 첨단기술연구소 2006 尖端技術硏究所論文集 Vol.17 No.1

802.11 b and 802.11g are both IEEE standards but they have different performances. Today, SOHO(Small Office Home Office) environment requires wireless channels. Therefore, in this paper, the general performance of wireless channels in SOHO environment is analyzed. Basically, we do the measurements for wireless environment between the host and the host AP. At first, we test the streaming service and then we confirm the service difference to use VOIP phone. We do several experiments to estimate the performance of the services in wireless environment of SOHO.

Melatonin이 수면에 미치는 영향

박철범,왕성근 대한생물치료정신의학회 1999 생물치료정신의학 Vol.5 No.2

OBJECTIVES : Author tried to evaluate the hypnotic effect of melatonin and melatonin induced daytime sleepiness and to identify the cumulative effect of short-term administration of melatonin for 3 successive days, and remaining effect after discontinuation. INTERVENTION : Subjects visited our laboratory by 08:00 at the first day, and they had baseline MSLT (from 10:00 to 22:00 at 2 hours' interval) while they had 7 naps during the day. Each time, the subjects completed SSS and RT before they underwent an MSLT to evaluate their sleepiness and to evaluate their performance. Next day, 6mg of melatonin was administered to healthy young males at 09:00 hour, and the concurrent effects on sleep latency, daytime sleepiness and reaction time were recorded. PARTICIPANTS : Sixteen healthy, normal young male college students participated in this study. Participating subjects were in good physical and psychological health and were asymptomatic as to sleep/wake complaintsRESULT : The result were summarized as follows.1. As compared to baseline, the hypnotic effect of melatonin appeared within 1 hour, and the effect continued over 7 hours. Sleep latency was normal range on the day of discontinuation. 2. Subjects had significantly more subjective daytime sleepiness after melatonin administration. Melatonin induced daytime sleepiness appeared within 3 hour after adminisration, and the condition continued over 7 hours.3. Compared to baselines, there was no effect on reaction time.4. The longer the reaction time of second drug administration day, the longer the reaction time of third drug administration day.

VPN 관리를 위한 망관리 구조

송왕철,김장형 濟州大學校 工科大學 産業技術硏究所 1998 尖端技術硏究所論文集 Vol.9 No.1

These days the VPN services are provided on basis of the bandwith contracts rather than through leased lines. They require the network managment capabilities. In this paper, hence, an architecture for the VPN service management is proposed on the basis of the structural considerations using the TMN concept. In addtion, the distributed processing technologies are introduced for implementing the architecture. The management architecture for VPN services may be composed of domains for customers and VPN service providers and public network operator/provider, and the domains can be managed via the TMN X interface. Hence, the architecture is modelled hierarchically. It is based on the structuring rule of partitioning and layering on ITU-T G.803 recommendation. On the architecture, the management operations via the X interface can have been performed efficiently by introducing the X.500 directory service and the ODP Trader.

VPN 관리를 위한 망관리 구조

송왕철,김장형 濟州大學校 産業技術硏究所 1998 산업기술연구소논문집 Vol.9 No.1

These days the VPN services are provided on basis of the bandwith contracts rather than through leased lines. They require the network managment capabilities. In this paper, hence. an architecture for the VPN service management is proposed on the basis of the structural considerations using the TMN concept. In addtion, the distributed processing technologies are introduced for implementing the architecture. The management architecture for VPN services may be composed of domains for customers and VPN service providers and public network operator/provider. and the domains can be managed via the TMN X interface. Hence. the architecture is modelled hierarchically. It is based on the structuring rule of partitioning and layering on ITU-T G.803 recommendation. On the architecture, the management operations via the X interface can have been performed efficiently by introducing the X.500 directory service and the ODP Trader.

Design and Implementation of a Security Management System for Secured OSI Directory Services

송왕철,김장형 濟州大學校 産業技術硏究所 1996 산업기술연구소논문집 Vol.7 No.1

In this paper, we have designed and implemented a security management system, which is based on the CMISE services. This system provides two security-related System Management Functions(SMFs) to security management users such as notification of a security event alarm and an audit trail of a security related event. These SMFs are implemented using osimis-4.0, OSI Network Management platform. The target of this security management system is secure X.500 directory services based on the Authentication Framework specified in the recommendation X.509. The security system is implemented using OSISEC and its services are data confidentiality, data integrity and non-repudiation of origin. Based on the OSI network management framework, we implemented a manager system which administers the keys and provides CMISE services, and also some remote agent systems which provide services for the events concerning the security system, while also interacting with MIB. Access Control SMF is being implemented.

망관리 명명 방식의 접근 제어 모델로의 확장

송왕철 濟州大學校工科大學産業技術硏究所 1996 尖端技術硏究所論文集 Vol.7 No.2

In this paper, the access control management function of several system management functions(SMFs) from the X.741 ITU-T recommendation is considered for security network management systems based on the common management information service element(CMISE) of OSI network management and a naming method using the general relationship model(GRM) is intended to extended to an access control model. When a manager is to perform network management operations through a remote agent in a distributed network, all managed objects (MO) in the management information base (MIB) that is managed by the agent must have a globally unique name so that each MO in the MIB is identified by the manager and access control functions for the MOs are carried out. Therefore, an access control model is proposed which extends the relationship used in the global naming scheme and in which each MO inherits access control characteristics from a domain class as a superclass in the inheritance tree of the MIB.

악성종양환자와 정상인이 발성한 모음의 좁은대역 스펙트럼값의 상관계수와 절대차이합 비교

양병곤,왕수건,조철우,김형순,김은지,권순복 한국음성과학회 2003 음성과학 Vol.10 No.4

The objective of this study was to examine two new parameters by which we could screen people with malignant vocal folds. The new parameters were the difference sums and Pearson correlation coefficients between adjacent pairs of intensity level matrices of narrow-band spectra. Audio files from the Korean Disordered Speech Database were analyzed by Praat, a speech analysis softWare, to obtain matrices of 400 intensity levels at 16 time points of each sustained vowel spectra. We limited our study to 12 normal subjects and 20 patients with malignant vocal folds who recorded at least three Korean vowels at a sound-proofed booth in Busan National University Hospital. Results indicated that the average coefficients of the abnormal subjects were much lower than those of the normal subjects while the average difference sums of the patients were much higher than those of the normal ones. Also, we found that the degree of the malignancy of the vocal folds was related to the coefficients and sums. However, some subjects at the initial stages of cancerous vocal folds yielded almost comparable coefficients and difference sums to those of the normal speakers. Further studies on larger databases will be desirable to set certain criteria or threshold levels for screening people with vocal fold diseases.

셀 패킹이 MPEG 비디오의 화질에 미치는 영향

최연성,송왕철,김장형 濟州大學校工科大學産業技術硏究所 1996 尖端技術硏究所論文集 Vol.7 No.1

In ATM-based B-ISDN, the traffic characteristics for the video signal are quite different from those of the data and/or voice. Serious problems of the quality of picture is brought due to a little cell loss. The output bits stream of MPEG encoder consists of macroblocks of different lengths. In this paper, we analyze packing methods of these macroblocks into ATM cell. Two kinds of packing approach, which are loosely and closely packing, to pack the video signal to ATM cell are considered. Loosely packing increases traffic in the networks. But it is shown that while due to cell loss for high speed video service loosely packed cell is robust in quality than closely one. We prove these theoretical approach and simulation results for real MPEG video.

Mobile Agent 기술을 이용한 네트워크 관리 구조

오양훈,송왕철 濟州大學校 情報通信硏究所 1999 情報通信硏究所論文集 Vol.2 No.-

The agent system has been considered as a part of the artificial intelligence technology. The mobile agent is an agent with mobility and an independent software program which runs on behalf of its operator. In this paper, a network management architecture using mobile agent technology in distributed network environment is proposed. The proposed architecture uses CORBA as the distributed object platform and the mobile agent is implemented using mobility of Java code. In order for mobile agent to communicate with SNMP agent. proxy object which can converse with CORBA object is proposed in the architecture. It can use several transparency characteristics that CORBA provides. In the result. it has been shown that the system.

Object Web 基盤의 OSI 망 管理

김강석,송왕철 濟州大學校工科大學産業技術硏究所 1998 尖端技術硏究所論文集 Vol.9 No.2

The Object web translates the existing CORBA IDL into the Java language and uses IIOP for interaction between a client and a server under the exiting Web environment. The client and the server through the Object Web. do not use HTTP, a web protocol, but IIOP that is an inter-object communication protocol provided by the CORBA. This paper proposes an architecture which consists of a gateway, a CORBA manager and an OSI agent. The CORBA manager is based on Object Web and can manage MOs in the OSI domain. The gateway has a role to translate CORBA IDLS into CMIS service and vice versa. Hence, an OSI agent can be abstracted into a CORBA agent. In this architecture, any client with the Web browser can manage OSI MOs in distributed environment. The client can invoke the management operations through CORBA server after it download the Java applet from HTTP server.