• Journal of Communications and Networks
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• 제11권1호
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• pp.36-41
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• 2009

The IEEE 802.16 wireless metropolitan area network (WMAN) standard is designed to correct expensive communication costs in CDMA-based mobile communication systems and limited coverage problems in wireless LAN systems. Thus, the IEEE 802.16e standard can provide mobile high-speed packet access between mobile stations and the Internet service provider through the base station with cheap communication fees. To efficiently accommodate voice over IP (VoIP) services in IEEE 802.16 systems, an uplink quality of service packet-scheduling scheme is proposed, and its performance is evaluated with an NS-2 network simulator in this paper. Numerical results show that this proposed scheme can increase the system capacity by 100% more than in the unsolicited rand service (UGS) scheme and 30% more than the extended real-time polling service (ertPS) scheme, respectively.

• 한국멀티미디어학회논문지
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• 제21권9호
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• pp.1110-1118
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• 2018

Personal sound amplifiers(PSAPs) provide accessible and affordable healthcare to individuals with hearing disability. Many studies are in progress for affordable PSAP development, but still people do not have a best fitting profile for the PSAP depending on their hearing test. As a result, they do not have a personalized and profiled music and sound, which are very helpful for those who has hearing problems. In this paper, we propose a device and mobile system to provide music with an equalizer value according to the hearing condition of an individual to prevent the hearing loss. In order to overcome the limit of frequency band of the equalizer in a smart phone, we developed bluetooth controlled equalizer based on the fitting profiles.

• 전자통신동향분석
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• 제33권5호
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• pp.1-12
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• 2018

One of the most remarkable aspects of the recently completed 3GPP release-15 (5G new radio phase 1) is the fact that some millimeter-wave bands have been officially approved for 5G mobile communications. Because the demand for higher transmission capacity has only grown, other millimeter-wave or even higher-frequency terahertz-wave bands have attracted more attention over time. Based on this effort, this paper reviews and discusses the existing technologies and their trends in high-frequency circuits and systems at the millimeter and terahertz-wave bands, particularly for future mobile communications.

• Journal of Electrical Engineering and information Science
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• 제2권5호
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• pp.33-39
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• 1997

In this paper we proposed a new traffic load shedding scheme which maximizes the throughput of traffic control by decreasing the load of the hot-spot cell using minimum load cell selection (MLCS) algorithm and deployed control flow of calls to define characteristic for hadoff region. we compared the performance of the random shedding approach with that of the proposed algorithm. The results of simulation show that MLCS algorithm minimizes the cal blocking rate under a high-density traffic compared to the random shedding scheme.

• 한국IT서비스학회지
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• 제9권4호
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• pp.207-217
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• 2010

This paper is concerned with a protection system for the mentally handicapped, which is utilizing a GPS receiver and mobile communications. The protection system consists of a location notification equipment, a location identification and management server, and a cell phone of guardian. The location notification equipment is made up of a GPS receiver, a CDMA communication module and a microprocessor. The equipment transfers the location of the mentally impaired to the location identification and management server when the handicapped gets out of a certain bound of the designated facility. The server marks the handicapped's location on the map in the server and also notifies the guardian's cell phone of the locations. With applying the proposed protection system to social welfare organizations related to the mentally handicapped, it is expected to efficiently contribute to the promotion of the handicapped's welfare.

• 한국통신학회논문지
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• 제31권6C호
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• pp.645-650
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• 2006

GSM(Global System for Mobile communications)은 전 세계에서 가장 대표적인 이동통신 표준으로서, 모바일 사용자들에게 이동성과 함께 편리성을 제공한다. 그러나 GSM 시스템은 사용자인증과정 중 MS(Mobile Station)의 IMSI(International Mobile Subscriber Identity)값이 노출되어 사용자를 정상적으로 인증할 수 없는 문제를 가지고 있다. 본고에서는 이러한 인증문제를 해결하기 위해 기존의 GSM 사용자인증 프로토콜에 기본을 둔 변형 메커니즘으로서, IMSI 값을 HLR(Home Location Register)로부터 암호화하여 전송함으로써 IMSI값의 노출을 막고, HLR에 의해 검증된 네트워크 개체만이 IMSI값을 사용하도록 하여 안전한 사용자인증을 제공한다. 또한 제안 메커니즘에서는 임시 아이디를 이용하여 사용자의 익명성을 제공할 뿐만 아니라, 기존의 GSM 사용자인증 프로토콜의 새로운 VLR과 이전의 VLR 간의 구조를 변경하지 않고 단계를 축소하여 빠른 사용자인증을 제공한다.

• 정보보호학회논문지
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• 제23권2호
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• pp.169-179
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• 2013

최근 스마트 폰, 스마트 패드와 같은 모바일 디바이스의 발전과 무선 네트워크 및 이동통신 네트워크의 발전으로 모바일 디바이스를 이용하는 서비스는 증가하고 있다. 그러나 무선 네트워크는 유선 네트워크에 비해 보안에 취약하므로 보다 강한 보안의 적용이 필요한 반면 배터리 기반의 모바일 디바이스는 낮은 계산 능력과 메모리 공간의 제약 및 무선통신에 사용되는 비용이 높기 때문에 보안의 적용은 효율적이어야 한다. 따라서 본 논문에서는 모바일 디바이스를 이용한 서비스에서 요구되는 보안 요구사항을 충족시키고 모바일 환경에 적합한 티켓 기반의 인증 기법을 제안한다.

• 경영과학
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• 제25권2호
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• pp.43-55
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• 2008

Contingent valuation method(hereafter CVM) is generally believed to be one of the most popular methods used for quantifying the value of non-market goods or services particularly by asking respondents of willingness to pay. This study deals with how to use CVM in calculating the value of mobile telephone service by suggesting methodology of estimation and eliminating biases. This study represents an attempt to estimate the WTP(Willingness To Pay) of the mobile telephone service using the face-to-face interview which is the qualitative technique is used. In this study, by using the single bound dichotomous choice model(SBDC) in order to analyze the valuation of mobile telephone service, WTP was estimated. Also we analyze the factors to pay for mobile service in which it becomes the important factor of demanding services. We used logit model. In order to provide robust estimates of WTP, we have used the Method of Montecarlo Simulation. Consequently, consumers showed that WTP about the mobile communications service is generally high. And it could know that the WTP will fell down as the specialized knowledge about the mobile communications frequency was high. It will be able to become the important part to not only the business carrier but also the policy maker to estimate the economic value of mobile telephone service.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2007년도 가을 학술발표논문집 Vol.34 No.2 (A)
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• pp.146-147
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• 2007

• 한국통신학회:학술대회논문집
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• 한국통신학회 2004년도 추계종합학술대회 논문 초록집
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• pp.146-146
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• 2004