실습선 가야호 충돌회피 동작에 관한 연구

김민석(Min-Seok KIM) 한국수산해양교육학회 2009 水産海洋敎育硏究 Vol.21 No.1

With the increase of marine traffic capacity, marine accidents have also been increased for recent several years. Especially watch officer must maneuver not entering into the safety minimum approaching distances when two power-driven vessels are crossing. The author calculated the safety minimum approaching distances to provide a navigator with them based on zig-zag motion by experimental ship. The obtained results are summarized as follows : 1. The greatest distance is to be kept by the give way vessel to avoid collision when the crossing course angle is 90°. In this case the safety minimum approaching distance must be more than from 5 times to 11 times of her own length according to her size. 2. The watch officer of the give way vessel must always take an action to avoid collisions outside of the safety minimum approaching distance. 3. When the navigator used rudder to small angle than to large angle to avoid other vessel he must take action outside the sufficient safety minimum outside distances in advance. 4. Risk of collision in crossing situation is more greater in obtuse situation than in acute one.

원격 측정 레벨계의 최소 탐지거리 성능 개선 방법

박동근 ( Dongkun Park ),이기준 ( Kijun Lee ) 대한원격탐사학회 2018 大韓遠隔探査學會誌 Vol.34 No.3

Recently, level meters have been associated with the safety and maintenance of industrial sites and require a wide measurement range. Generally, to ensure the measurement range of the level meter, the measurement environment is improved to reduce the noise or to compensate the distortion of the signal through signal processing. The noise of FMCW (Frequency Modulated Continuous Wave) radar level meter or the distortion of the signal affects the near region characteristics of the level gauge, resulting in a reduction of the minimum detection distance. In this paper, an equalizer filter considering characteristics of window function and bit spectrum is applied to remove the noise in the near region of the level meter to improve the minimum detection distance performance and to improve the measurement reliability in the vicinity of the level meter, which is relatively difficult to detect, we want to improve the detection range.

해상교통량 기반의 해상교통 집중관제 구역 도출에 관한 기초 연구

박상원,박영수,나송진 한국해양경찰학회 2019 한국해양경찰학회보 Vol.9 No.2

Korea Coast Guard have a Vessel Traffic Services(VTS) in the harbor and coastal area to ensure ship traffic safety and efficiency, and provides necessary information to vessels. However, it is difficult to examine and control the encounter relations that are associated with multiple vessels in the VTS area within a limited time. The purpose of this study is to propose an area that should be intensively controlled for efficient maritime traffic control. First, we confirmed that the maritime traffic volume is an important factor in the VTS area through previous studies and literature on VTS service zone setting. For the Busan New Port, which is expected to increase the traffic congestion due to the expansion of the berth, the distribution of vessel density, vessel collision risk distribution, and minimum distance were analyzed using AIS data for 5 days and compared with marine accidents occurred within the zone. As a result of analysis of ship density, it is analyzed that the distribution of ships per unit area is large in Gadeok-sudo area and relatively large ship is passing. As a result of the risk analysis of ship collision, the percentage of dangerous vessels was high in the coastal area outside Gadeok-sudo, but the ratio of very dangerous vessels was high inside Gadeok-sudo. As a result of analysis of the minimum separation distance from the other vessels, 77.6% of the vessels that pass through the coastal area outside the Gadeok-sudo were navigating at a distance of 4cable or less. Since the opening of the Busan New Port VTS, marine casualties were found to be the highest in the coastal areas outside the Gadeok-sudo, compared with the other areas. In conclusion, it was analyzed that the Gadeok-sudo should be controlled intensively for large ships with a large volume of traffic, and the coastal area outside the Gadeok-sudo should be controlled intensively for small ships with closed distance. This is to provide information that can assist the VTS officer who need to monitor the entire control area within a limited time to make appropriate decisions. 해양경찰은 항만 및 연안해역에 선박교통안전과 효율성을 확보하기 위해 해상교통관제시스템(VTS)을 두어 관제구역 내 선박 동정을 관찰하고 필요한 정보를 제공하고 있다. 그러나 관제구역 내의 다수 선박과 연관되는 조우 관계를 제한된 시간안에서 살펴보고 관제하는 것은 쉽지 않은 일이다. 본 논문은 효율적인 해상교통관제를 위해 집중적으로 관제가 되어야 하는 구역을 제시하는 것을 목적으로 한다. 먼저 VTS 서비스구역 설정과 관련한 선행연구 및 문헌을 통해 해상교통량이 관제 서비스구역의 중요한 요소임을 확인했다. 그리고 선석 확대에 따라 해상교통 혼잡도가증가할 것으로 예상되는 부산신항을 대상으로 5일간 AIS 데이터를 이용해서 관제구역 선박밀도, 선박충돌위험도 분포, 최소이격거리의 분포를 분석하고 구역 내 발생한해양사고와 비교했다. 선박밀도를 분석한 결과 단위면적 당 선박분포가 가덕수도 해역이 많으며 상대적으로 큰 선박이 통항하는 것으로 분석되었다. 선박충돌위험도 분석결과 위험선박의 비율은 가덕수도 밖의 연안 구역이 높았지만, 매우 위험한 선박의 비율은 가덕수도 안쪽이 높게 나타났다. 타선과의 최소 이격거리를 분석한 결과, 가덕수도 밖 연안구역을 통항하는 선박의 77.6%가 4cable 이하의 이격거리를 두고항해하는 것으로 분석되었다. 부산신항 VTS 개소 이후 해양사고는 가덕수도 밖 연안구역에서 총 6건의 충돌사고가 발생하여, 다른 구역에 비해서 가장 많은 것으로나타났다. 종합하면, 가덕수도는 통항량이 많은 대형선을, 가덕수도 밖의 연안 구역은 이격거리가 짧은 소형선을 집중적으로 관제가 되어야 할 것으로 분석되었다. 이를 이용해 제한된 시간 내 관제구역 전반을 감시해야 하는 해상교통관제사에게 적절한 의사결정을 지원할 수 있는 정보를 제공하고자 한다.

홀로그래픽 데이터 저장장치에서 부호율 1/2인 이진 변조부호의 최소거리에 따른 성능 분석

정성권(Seongkwon Jeong),이재진(Jaejin Lee) 대한전자공학회 2015 전자공학회논문지 Vol.52 No.10

이중 교신 위성 시나리오에서 인접 위성 간섭 제거 기법

박홍원(Hong Won Park),장윤선(Youn Seon Jang) 대한전자공학회 2020 전자공학회논문지 Vol.57 No.8

The Coexistence of OFDM-Based Systems Beyond 3G with Fixed Service Microwave Systems

Jo Han-Shin,Yoon Hyun-Goo,Lim Jae-Woo,Chung Woo-Ghee,Yook Jong-Gwan,Park Han-Kyu The Korea Institute of Information and Commucation 2006 Journal of communications and networks Vol.8 No.2

In this paper, we study the coexistence of orthogonal frequency division multiplexing (OFDM)-based systems beyond 3G (B3G) and point-to-point (P-P) fixed service (FS) microwave systems. The advanced general analytical model derived via a power spectral density (PSD) analysis proposed in this paper has two advantages in comparison with the conventional minimum coupling loss (MCL) method. First, the interfering signal power that appears in the band of a victim system can be easily assessed without a spectrum emission mask. Second, when transmit power is not allocated to some subcarriers overlapping the band of the victim system in order to mitigate B3G OFDM-based systems interference with other systems, the general analytical model can successfully assess the interference from the B3G systems into FS systems, whereas the MCL method incorporating the spectrum emission mask cannot be applied in the presence of the same interference condition. The proposed model can be derived in a closed form and is simply implemented with the help of simulation, and thus the solution can be obtained in significantly reduced time. Through application of the proposed model, coexistence results are analyzed in a co-channel and adjacent channel with respect to guard band and minimum separation distance.

Minimum Distance Test and Estimation in the General Aalen Model

So, Beong-Soo 梨花女子大學校 韓國生活科學硏究院 1992 韓國生活科學硏究院 論叢 Vol.50 No.-

Let N=(N_s^l,…, N_5^d)be a multivariate counting process with intensities of the form λ(α)=(λ_s^lα_a^l,…,λ_s^dα_S^d). We consider the model where some of the α's are parametrized by the Euclidean parameter θ∈Θ and the rest of α's are regarded as nuisance parameters. In this framework we will derive the asymptotic distribution of the minimum distance type test statistics : ??|??-F_θ|which is based on the procuct limit estimator(PLE)?? and show that minimum distance estimator(MDE)?? of θ defined by : ??|??-F_θ|=|??-??| is asymptotically normal and has a locally asymptotic minimax(LAM) optimality. We also propose computationally tractable bootstrap versions of these quantities and show that they have the same asymptotic properties as desired. 본 논문에서는 일반적으로 강도함수가 λ(α)=(α_iλ_i)=l,…,d인 형태로 주어지는 다변량 계수확률과정 N(t)=(N_i(t))i=l,…,d을 고려한다. 이 모형에서 α는 확률과정의 강도함수를 지정하는 미지의 함수로서 그 일부는 유한차원의 관심모수벡타를 포함하여 나머지는 미지의 부수적인 함수들로 간주된다. 본 연구는 위의 모형에서의 승법극한추정치에 근거한 최소거리 검정통계량의 점근분포를 유도하고 최소거리 추정량의 점근분포가 정규분포임을 보이고 또한 국소점근 minimax최적성을 가짐을 증명한다. 아울러 이들 검정 통계량과 측정량들의 Bootstrap 추정치를 고려하여 대표본에서 본래의 절차들과 동일한 성질을 가짐을 보인다. Let N_=(N_s^1,…,N_s^d)be a multivariate counting process with intensities of the form λ(α)=(λ_s^1c_a^1,…,λ_s^dα_s^d).We consider the model where some of the α's are parametrized by the Euclidean parameter θ∈Θ and the rest of α's are regarded as nuisance parameters. In this framework we will derive the asymptotic distribution of the minimum distance type test statistics : inf|F△_n-F_ θ|which is based on the product limit estimator(PLE) F△_n and show that minimum distance estimator(MIDE) θ^△_n of θ definde by:inf|F△_n-F_ θ|=|F△_n-F_ θ^|is asymptotically normal and has a locally asymptotic minimax(LAM) optimality. We also propose computationally tractable bootstrap versions of these quantities and show that they have the same asymptotic properties as desired.

사인 디자인에 있어서 문자의 최소판독크기 산출

한욱현(주저자) ( Wook Hyun Han ) 커뮤니케이션디자인학회 2014 커뮤니케이션 디자인학연구 Vol.46 No.-

사인디자인에 있어서 판독가능거리는 정보전달의 가능성을 결정 짓은 핵심 요소다. 이 때문에 디자이너는 사인물의 기능과 위치를 감안하여 판독이 되어야만하는 최소 거리를 산정하고, 그 거리에서 사인물상의 문자정보가 판독이 가능하도록 설계하여야 한다. 사인물에 적용된 문자정보는 적용서체, 글자크기, 정보취득자의 시력에 따라 판독이 가능한 최대 거리가 달라진다. 본 연구에서는 서체에 따른 샘플글자의 구조파악을 통해 해당서체의 크기에 따른 최대 판독가능거리 산출식과 해당 서체로 기록된 문자정보가 거리에 따라달라지는 최소판독크기 산출식을 도출하였다. The distance within which sign designs are legible is the most crucial factor in determining the delivery of information. Given this, designers calculate the minimum legible distance considering the function and distance of the sign, while also manufacturing according to the distance in order that is the information is decipherable. The maximum distance of a sign from an observer depends on the font, letter size and eyesight of the information for the information contained in a sign. This research, through the sample letter’s structure understanding in accordance with the font, has drawn out calculating formulas on the maximum legible distance according to the font’s size. In addition, the research has also drawn out the formula on the minimum legible size altered by the distance of the information contained in the font.

오염된 자료에서 차이측도 추정량의 효율성 비교

홍종선,이지선 성균관대학교 응용통계연구소 2003 통계연구 Vol.11 No.-

임의의 자료에 특이값이 포함되어 있을 경우 최소헬링거거리추정량과 최소음지수차이추정량을 통해 얻은 모수에 대한 추정값이 최대가능도 추정량을 통해 얻은 모수의 추정값보다 자료에 대한 설명력이 높다는 기존의 연구를 바탕으로 모의실험을 실행해 보았다. 그 결과 최소음지수차이추정량을 통해 얻은 평균의 추정값은 최대가능도추정량을 통해 얻은 추정량 보다 특이값의 영향을 적게 받는 것으로 나타났으나, 표준편차의 경우 최소음지수차이추정량은 최대가능도추정량에 비해 특이 값의 영향을 적게 받는 반면, 최소헬링거거리추정량은 특이값의 영향을 많이 받는 것으로 확인되었다. When some outliers are contained an arbitrary data, it is known that minimum Hellinger distance estimators and minimum negative exponential disparity estimators are more efficient than any other classical estimators. Based on these facts, we did some simulation study by using Monte Carlo methods. we obtain the results that estimates of sample means obtained by minimum negative exponential dispariry estimation methods are affected less than those by minimum Hellinger distance estimation method, but estimates of sample standard deviations obtained by minimum negative exponential disparity estimation methods are affected less than those by maximum likelihood estimation methods and more than those by minimum Hellinger distance estimation method.

Minimum distance estimator for sharp regression discontinuity with multiple running variables

Choi, Jin-young,Lee, Myoung-jae Elsevier 2018 economics letters Vol.162 No.-

<P><B>Abstract</B></P> <P>In typical regression discontinuity, a running variable (or ‘score’) crosses a cutoff to determine a treatment. There are, however, many regression discontinuity cases where multiple scores have to cross all of their cutoffs to get treated. One approach to deal with these cases is one-dimensional localization using a single score on the subpopulation with all the other scores already crossing the cutoffs (“conditional one-dimensional localization approach, CON”), which is, however, inconsistent when partial effects are present which occur when some, but not all, scores cross their cutoffs. Another approach is multi-dimensional localization explicitly allowing for partial effects, which is, however, less efficient than CON due to more localizations than in CON. We propose a minimum distance estimator that is at least as efficient as CON, yet consistent even when partial effects are present. A simulation study demonstrates these characteristics of the minimum distance estimator.</P> <P><B>Highlights</B></P> <P> <UL> <LI> There are sharp regression discontinuity designs with multiple running variables (‘multiple scores’). </LI> <LI> If only some, but not all, scores cross their cutoffs, ‘partial effects’ can occur. </LI> <LI> Partial effects make the usual one-dimensional localization estimators inconsistent. </LI> <LI> Multi-dimensional localization estimators are consistent under partial effects, but inefficient. </LI> <LI> Our minimum distance estimator is efficient, and consistent under partial effects. </LI> </UL> </P>