• 대한교통학회지
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• 제26권4호
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• pp.185-194
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• 2008

일반적인 도로사업의 수요예측 과정에서 해당도로구간을 어떤 기종점간을 통행하는 차량들이 얼마만큼 이용하는지 알기 위해서 Select Link Analysis가 주로 이용된다. 하지만 이런 결과에 대한 분석방법으로는 현재 Select Link Analysis만이 거의 유일하게 이용되고 있고, 이 외의 분석방법에 대한 연구는 전무한 실정이다. 따라서 전문가들은 각 기종점에서 해당 도로를 이용하여 통행하는 통행량을 알아보는 객관적 자료로서 이 분석방법에 거의 전적으로 의존하고 있다. 본 연구는 Select Link Analysis와는 다른 접근방법을 통해 신설 도로에 대한 각 기종점별 이용 정도를 예측할 수 있는 모형의 개발을 목적으로 하며, 그 접근방법으로는 Network의 시공간적 특성을 이용하였다. 또한 개발된 모형의 유의성 검증을 위해 모형에 의한 결과에 대한 비교지표로서 Select Link Analysis 결과를 이용하였다. 개발된 모형은 지역간 통행과 도시 내부 통행 두 가지의 경우에 대한 사례분석을 통해 그 유의성을 검증하였고, 그 결과 비교지표와의 상관계수가 0.82 정도로 비교적 높게 나타나 본 연구에서 제시한 개념이 유의성을 가짐을 알 수 있었다.

• 한국통신학회논문지
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• 제37C권11호
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• pp.1045-1053
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• 2012

Link-16은 가장 널리 사용 중인 전술데이터링크로써 TDMA(Time Division Multiple Access)를 기반으로 동작한다. Link-16은 안정적이지만 전송 속도가 매우 낮아 전술 메시지, 음성 등 작은 사이즈의 데이터 전송을 지원한다. 그러나 최근 효과중심작전(EBO: Effect-Based Operation)에 대한 관심이 증가하면서, Link-16을 통해 이미지와 같은 상황 인식 정보를 전송하려는 동향이 있다. 이미지는 기존 메시지에 비해 크기가 매우 크기 때문에 Link-16의 Static TDMA가 아닌 별도의 TDMA 스케줄링이 필요하다. 따라서 본 논문에서는 Link-16의 MAC을 진화시킨 Link-16K를 제안하였다. Link-16K는 Link-16과 호환성을 유지한다. 그리고 이미지 전송을 효과적으로 지원하기 위해 DTDMA(Dynamic TDMA), 새로운 재전송 방법, 새로운 패킹 방법을 포함한다. 제안하는 아이디어의 시뮬레이션 결과를 통해 이미지 전송 시간이 단축되었고, 채널 효율성이 높아졌음을 확인하였다.

• Journal of Communications and Networks
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• 제12권3호
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• pp.209-215
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• 2010

In an asymmetrical speed channel environment like asymmetric digital subscriber line, the up-link bandwidth is normally smaller than the down-link bandwidth, which will lead to extremely low utilization of down-link bandwidth when current P2P video transmission is applied. To overcome this, a new fast P2P video transmission method applied in an asymmetrical speed channel environment is proposed in this paper. On the basis of the many-to-one concept, the proposed method uses a new multipeer aggregation technique to enhance the utilization of down-link bandwidth. In addition, an adaptive peer assignment algorithm is also introduced in order to minimize the overall transmission time. Experimental results show that by using our proposed method, the utilization of down-link bandwidth is significantly improved, and the overall transmission time is greatly reduced.

• 한국항행학회논문지
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• 제17권3호
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• pp.285-291
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• 2013

본 논문에서는 무선 애드 혹 링크 품질을 보장하기 위하여 새로운 STM기반의 미디어 스트리밍 기법을 제안 하였다. 제안된 기법은 스트리밍 모니터링, 스트리밍 보장, 그리고 스트리밍 갱신과정을 거쳐 링크 품질이 보장되도록 하였으며, 스트리밍 $t_{new}$에 의해 미디어 프레임들이 모니터링되도록 하였다. 그리고 프레임의 크기에 따른 미디어 스트리밍 갱신 알고리즘을 이용하여 링크 오류율과 재전송률을 최소화하도록 하였다. 시뮬레이션 결과 제안된 기법이 STCP기법, 그리고 RMST기법에 비해서 성능이 우수함을 보인다.

• 한국통신학회:학술대회논문집
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• 한국통신학회 1983년도 추계학술발표회논문집
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• pp.108-111
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• 1983

This paper presents a new method for the optimum capacity assignment in store-and-forward communication networks under a total fixed-capacity constraints. Any two link capacities needed in this method can have the desirable quantites and then other capacities can be obtained from the fixed two link capacities. When the minimum and the maximum capacities that are the quantites of the conventional method are fixed, the total average time delay from the new method is almost the same as that from the conventional method. And when the minimum capacity is fixed, the new method gives smaller average time delay.

• Structural Engineering and Mechanics
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• 제46권4호
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• pp.487-504
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• 2013

In the present work a new friction device, with a set of single or double rotational friction flanges and a link element, is described and tested. The mechanism may be applied for the strengthening of existing r/c or steel buildings as well as in new constructed buildings. The device has selectable variable behavior in different levels of displacement and an interlock mechanism that is provided by the link element. The link element may be designed to lock at preselected level of displacement, offering in this way an extra safety reserve against strong earthquakes. A summary of the existing literature about other similar mechanisms is initially presented in this paper. The proposed mechanism is presented and described in details. Laboratory experiments are presented in detail and the resulted response that proves the efficiency of the mechanism at selectable levels of strength capacity is discussed. Drawings of the mechanism attached to a r/c frame with connection details are also included. Finally a dynamic analysis of two r/c frames, with and without the proposed mechanism attached, is performed and the resulted response is given. The main conclusion is that the proposed mechanism is a cheap and efficient devise for the improvement of the performance of new or existing framed buildings to seismic loads.

• Journal of Communications and Networks
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• 제2권1호
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• pp.5-17
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• 2000

cdma2000 offers several enhancement as compared to TIA/EIA-95, although it remains fully compatible with TIA/EIA-95 systems and allows for a smooth migration from one to the other-Major new capability include:1)connectivity to GSM-MAP in addition to IP and IS-41 networks; 2) new layering with new LAC and MAC architectures for improved service multiplexing and QoS management and efficient use of radio resource ;3) new bands and band widths of operation in support of various operator need and constraints, as well as desire for a smooth and progressive migration to cdma 2000; and 4) flexible channel structure in support of multiple services with various QoS and variable transmission rates at up to 1 Mbps per channel and 2 Mbps per user. Given the phenomenal success of wireless services and desire for higher rate wireless services. improved spectrum efficiency was a major design goal in the elaboration of cdma2000. Major capacity enhancing features include; 1) turbo coding for data transmission: 2)fast forward link power control :3) forward link transmit diversity; 4) support of directive antenna transmission techniques; 5) coherent reverse link structure; and 6) enhanced access channel operation. As users increasingly rely on their cell phone at work and at home for voice and data exchange, the stand-by time and operation-time are essential parameters that can influence customer's satisfaction and service utilization. Another major goal of cdma2000 was therefore to enable manufacturers to further optimize power utilization in the terminal. Major battery life enhancing features include; 1) improved reverse link performance (i.e., reduced transmit power per information bit; 2) new common channel structure and operation ;3) quick paging channel operation; 4) reverse link gated transmission ; and 5) new MAC stated for efficient and ubiquitous idle time idle time operation. this article provides additional details on those enhancements. The intent is not to duplicate the detailed cdma2000 radio access network specification, but rather to provide some background on the new features of cdma2000 and on the qualitative improvements as compared to the TIA/EIA-95 based systems. The article is focused on the physical layer structure and associated procedures. It therefore does not cover the MAC, LAC, radio resource management [1], or any other signaling protocols in any detail. We assume some familiarity with the basic CDMA concepts used in TIA/EIA-95.

• 지식정보인프라
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• 통권7호
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• pp.134-140
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• 2001

To know about the performance of KREONET, we installed an active network performance measurement tool, PingER. For customization, we modified its architecture and some codes. Although this customization is a minor change of PingER, it gives much benefit and convenience for both operators and users. Using PingER, we can measure the effect of the STAR TAP link. The new networking through the link is a little bit slower than the previous networking. But the new link shows far fewer packet losses and provides more reliable networking.

• Journal of Communications and Networks
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• 제10권3호
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• pp.331-337
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• 2008

In this paper, we investigate survivability in wavelength division multiplexing (WDM) mesh networks and propose a new algorithm called improved shared-path protection (ISPP) to completely tolerate the double-link failures. Compared with previous algorithms for protecting double-link failures, i.e., shared-path protection (SPP) and shared-link protection (SLP), the advantage of ISPP is to allow primary paths and backup paths to share the mixed wavelength-links based on the proposed new rules in which some primary wavelength-links can be changed to mixed wavelength-links, which can be shared by primary paths and backup paths. In addition, some mixed wavelength-links also can be shared by different backup paths for saving resources. Simulation results show that ISPP algorithm performs better in resource utilization ratio and blocking probability than conventional SPP and SLP algorithms.

• 한국통신학회논문지
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• 제36권12B호
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• pp.1586-1594
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• 2011

LED-ID (light emitting diode - identification) technology is the new paradigm in the identification technology environment. LED-ID system typically needs line of sight (LOS) that supports narrow FOV transceivers links to achieve high data rate. On the other hand, narrow FOV reduces the coverage area. Therefore, the number of tags is increased significantly to cover the whole area. In this case number of link switching is increased when the reader moves within whole coverage area. Link switching delay is the important factor for the moving reader to maintain the communication with high data rate and better QoS. In this paper we propose in literature a new link switching scheme and measure the link switching delay time for LED-ID system. The simulation results show that the proposed link switching scheme is a possible candidate for multi-tag LED-ID system.