• Proceedings of the Korean Information Science Society Conference
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• 2003.10c
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• pp.319-321
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• 2003

모바일 컴퓨팅 환경은 크게 모바일 노드, 무선망, 그리고 이동성이라는 기술로 이루어진다. 이음새없는 (seamless) 이동성을 제공하기 위한 기존의 Shadow Registration 방법은 핸드오프가 발생하기 이전에 이웃한 모든 노드들(AAAF/sbu n/)에게 모바일 노드의 관련 정보를 사전등록(Shadow Registration)하는 방법을 제안하여 핸드오프 이후에 발생하는 끊김이나 지연을 방지하였다. 그러나 이러한 Shadow Registration의 경우 백본 네트워크에 불필요한 트래픽 발생 및 데이터 관리라는 문제를 야기시킨다. 본 논문은 이러한 문제점들을 개선하고자 새롭게 사전등록 트리거 영역(STR: Shadow Trigger Region)을 설정하고, STR 내에 모바일 노드(MN)가 위치할 경우 MN의 이동 방향을 이용하여 최소한의 사전등록영역(SRR: Shadow Registration Region)을 찾아내는 방법을 제안한다. 결과적으로 제안된 SRR 은 최대 2 개의 이웃노드(AAAF$_2$)에게만 사전등록을 요청하면 되므로, 기존의 방법에 비해 최대 ∑(n­2)번의 사전등록 횟수를 줄이면서 끊김과 지연도 방지할 수 있는 효과적인 방법이다.

• Proceedings of the Korea Information Processing Society Conference
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• 2003.11b
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• pp.1165-1168
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• 2003

모바일 컴퓨팅 환경에서 이동성은 등록을 통해 이루어지고 있으며, 이음새 없는(seamless) 이동성을 제공하고자 많은 연구들이 진행되어 있으며, 그 중 방문하고자 하는 네트워크(Foreign Network)에 등록하는 시점을 언제로 하느냐에 따라 크게 다음의 2 가지 방법으로 대별된다. SIP-Registration은 핸드오프가 발생한 이후 등록(AAAF)을 함으로써 통화하는 중에 끊김(disruption)이나 지연(delay)이 발생한다. 이를 개선한 SIP-Shadow-Registration 방법은 핸드오프가 발생하기 이전에 이웃한 모든 노드들$(AAAF_n)$에게 모바일 노드(MN)의 관련 정보를 사전등록(Shadow Registration)하여 핸드오프 이후에 발생하는 끊김이나 지연을 방지하였다. 그러나 SIP-Shadow-Registration은 실제 사용하지 않는 n-2 개의 MN와 관련된 백본 네트워크에 불필요한 데이터 전달 및 관리라는 문제를 야기시킨다. 본 논문은 이러한 문제점들을 개선하고자 사전등록영역(SRR: Shadow Registration Region)을 구성하고 이의 알고리즘을 제안한다. 결과적으로 SIP 기반의 이동성이 필요할 때, 최소한의 사전등록영역을 통해 끊김이나 지연도 방지하고 추가적인 데이터 관리 문제도 해결할 수 있는 효과적인 방법이다.

• Journal of KIISE:Information Networking
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• v.31 no.5
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• pp.490-500
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• 2004

In mobile/wireless environment, mobility management is widely being focused as one popular researches. But, disruption happens when messages are exchanged between nodes as registration is made after handoff, and unnecessary traffic occurs because of the use of the Random-walk model, in which the probability for MN to move to neighboring cells is equal. In order to solve these problems, this study proposes a technique and algorithm for composing Directional Shadow Registration Region (DSRR) that provides seamless mobility. The core of DSRR is to prevent disruption and unnecessary traffic by minimizing the number o) neighboring cells with a high probability of handoff (AAAF). This study sensed the optimal time for handoff through regional cell division by introducing a division scheme, and then decided DSRR, the region for shadow registration, by applying direction vector (DV) obtained through directional cell sectoring. According to the result of the experiment, the proposed DSRR processes message exchange between nodes within the intra-domain, the frequency of disruptions decreased significantly compared to that in previous researches that process in inter-domain environment. In addition, traffic that occurs at every handoff happened twice in DSRR compared to n (the number of neighboring cells) times in Previous researches. As an additional effect, divided regions obtained from the process of composing DSRR filter MN that moves regardless of handoff.

• Journal of the Korean Institute of Rural Architecture
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• v.17 no.1
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• pp.19-26
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• 2015

The old Samcheok construction company housing in Donghae City was built for employees of Nitrogenous lime factory with railway construction in 1939. The 31 company houses are arranged in a rows including a House A, two No. 2 and 3 Houses, a dormitory, 12 row houses of two households, and 15 row houses of four households. At present, they are preserved with prototype at that time of building as a private company. Researching the architectural characteristics from A and No. $2{\cdot}3$ detached houses of them, the results are as follows. The tea room, living room, and kitchen are centralized and connected with toilet, bathroom, and maid's room by corridor. The exterior wall was finished with paintwork on cement mortar on stud wall framing plastered. The key exterior elements such as diamond shaped asbestos slate, large openings, corner bay window, lintel cornice are in accordance with drawings that they were first designed. The wooden roof structure is based on the structure that supports transverse load with a beam and beam plate instead of thrust. The kitchen and toilet are remodelled and only seem to be a mere shadow of their former self, but the position of sink and toilet bowl is the same as before.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.5
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• pp.957-962
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• 2016

Current terrestrial Digital Multimedia Broadcasting (T-DMB) is conducting the emergency alert broadcast, or can view a variety of broadcasting. However, propagation shadow area is a situation where the service is limited due to limitations of facilities investment. In addition, there is the problem of T-DMB broadcasting is for viewing only a restricted area and a mobile device because the mobile is also T-DMB viewing device impossible. In this paper, it receives a T-DMB broadcasting as a way to solve the problems of the T-DMB system, which was studied the re transmission to the mobile device. Accordingly, by receiving the broadcast may be watched in the mobile device the T-DMB reception impossible. Also provides a one-way/two-way authentication mechanism using a conditional access function, and the system was configured so that the user can watch only the registered broadcasting.

• Journal of the Korean Society of Marine Environment & Safety
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• v.14 no.2
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• pp.163-168
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• 2008

Ship detection from satellite remote sensing is a crucial application for global monitoring for the purpose of protecting the marine environment and ensuring marine security. It permits to monitor sea traffic including fisheries, and to associate ships with oil discharge. An automatic ship detection approach for RADARSAT Fine Synthetic Aperture Radar (SAR) image is described and assessed using in situ ship validation information collected during field experiments conducted on August 6, 2004. Ship detection algorithms developed here consist of five stages: calibration, land masking, prescreening, point positioning, and discrimination. The fine image was acquired of Ulsan Port, located in southeast Korea, and during the acquisition, wind speeds between 0 m/s and 0.4 m/s were reported. The detection approach is applied to anchoring ships in the anchorage area of the port and its results are compared with validation data based on Vessel Traffic Service (VTS) radar. Our analysis for anchoring ships, above 68 m in length (LOA), indicates a 100% ship detection rate for the RADARSAT single beam mode. It is shown that the ship detection performance of SAR for smaller ships like barge could be higher than the land-based radar. The proposed method is also applied to estimate the ship's dimensions of length and breadth from SAR radar cross section(RCS), but those values were comparatively higher than the actual sizes because of layover and shadow effects of SAR.