• The Journal of the Korea Contents Association
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• v.15 no.7
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• pp.322-329
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• 2015

The purpose of this study was to examine the oral health knowledge of maritime police officers, whose job belonged to the cluster of special occupations, in an effort to provide some information on the development of oral health education programs. The subjects in this study were 499 maritime police officers. After a survey was conducted from March to September, 2013, it's found that just 104 respondents(22.8%) had experience of receiving oral health education. In terms of general knowledge, the respondents who received that education were different from the others who didn't in the level of knowledge on the items related to temporomandibular joint(p=0.026), and there were no differences between the two in knowledge of periodontal health. As for prevention-related knowledge, they had a good knowledge of fluorine. Concerning needs for oral health education, 67.1 percent considered oral health professional manpower to be necessary, and 77.9 percent of the respondents who received oral health education gave this reply(p=0.004). Regarding preference for educational content, the right toothbrushing method was most preferred, followed by oral counseling, the use of oral hygiene supplies, the selection of dentifrice, and nutrition/anti-smoking education. The findings of the study suggest that the development of oral health education programs geared toward the cluster of special occupations such as maritime police is required.

• Journal of Advanced Marine Engineering and Technology
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• v.37 no.2
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• pp.144-148
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• 2013

In this paper, the ultra water-repellent thin films were prepared by RF PECVD. On the basis of surface morphology, chemical bonding states and plasma diagnostics, a formation model of clusters for the ultra water-repellent films was discussed from considerations of formation process and laser scattering results. Moreover, using laser scattering method, the relative change of quantity of nano-clusters or size of agglomerates could be confirmed. From the results, the films were deposited with nano-clusters and those of agglomerates, which formed in organosilicon plasma, and formation of agglomerates were depended on the deposition time.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.4
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• pp.483-491
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• 2021

The identification of regional collision risks in water areas is significant for the safety of navigation. This paper introduces a new method of collision risk assessment that incorporates a clustering method based on the distance factor - hierarchical clustering - and uses real-time data in case of several surrounding vessels, group methodology and preliminary assessment to classify vessels and evaluate the basis of collision risk evaluation (called HCAAP processing). The vessels are clustered using the hierarchical program to obtain clusters of encounter vessels and are combined with the preliminary assessment to filter relatively safe vessels. Subsequently, the distance at the closest point of approach (DCPA) and time to the closest point of approach (TCPA) between encounter vessels within each cluster are calculated to obtain the relation and comparison with the collision risk index (CRI). The mathematical relationship of CRI for each cluster of encounter vessels with DCPA and TCPA is constructed using a negative exponential function. Operators can easily evaluate the safety of all vessels navigating in the defined area using the calculated CRI. Therefore, this framework can improve the safety and security of vessel traffic transportation and reduce the loss of life and property. To illustrate the effectiveness of the framework proposed, an experimental case study was conducted within the coastal waters of Mokpo, Korea. The results demonstrated that the framework was effective and efficient in detecting and ranking collision risk indexes between encounter vessels within each cluster, which allowed an automatic risk prioritization of encounter vessels for further investigation by operators.

• Geomechanics and Engineering
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• v.25 no.2
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• pp.135-142
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• 2021

This study provided a new research perspective for processing and analyzing AE data to evaluate rock failure. Cluster method and information entropy theory were introduced to investigate temporal and spatial correlation of acoustic emission (AE) events during the rock failure process. Laboratory experiments of granite subjected to compression were carried out, accompanied by real-time acoustic emission monitoring. The cumulative length and dip angle curves of single links were fitted by different distribution models and distribution functions of link length and directionality were determined. Spatial scale and directionality of AE event distribution, which are characterized by two parameters, i.e., spatial correlation length and spatial correlation directionality, were studied with the normalized applied stress. The entropies of link length and link directionality were also discussed. The results show that the distribution of accumulative link length and directionality obeys Weibull distribution. Spatial correlation length shows an upward trend preceding rock failure, while there are no remarkable upward or downward trends in spatial correlation directionality. There are obvious downward trends in entropies of link length and directionality. This research could enrich mathematical methods for processing AE data and facilitate the early-warning of rock failure-related geological disasters.

• Proceedings of the Korean Society of Computer Information Conference
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• 2014.01a
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• pp.477-478
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• 2014

일반적으로 컴퓨터 클러스터는 제공하는 기능에 따라 구축 비용이 고가이며 공간 확보, 냉난방, 전원 등을 위한 유지 비용을 무시할 수 없다. 그러므로, 일반 개발자들이 컴퓨터 클러스터를 보유하는 것은 쉬운 일이 아니다. 이러한 상황에서 교육용 및 연구용으로 가격대비 성능이 만족스러운 라즈베리 파이를 기반으로 한 컴퓨터 클러스터를 구축하여 분산 컴퓨팅 및 클라우드 컴퓨팅 시스템 개발을 위한 테스트 베드로 활용하고자 한다. 본 논문의 실험 결과는 라즈베리 파이 클러스터가 병렬 프로그래밍을 위한 효과적인 테스트 베드가 될 수 있음을 보인다.

• Journal of Institute of Control, Robotics and Systems
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• v.22 no.2
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• pp.133-138
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• 2016

This paper describes the track initiation and target-tracking filter for ship tracking in a marine environment by using Light Detection And Ranging (LiDAR). LiDAR with three-dimensional scanning capability is more useful for target tracking in the short to medium range compared to RADAR. LiDAR has rotating multi-beams that return point clouds reflected from targets. Through preprocessing the cluster of the point cloud, the center point can be obtained from the cloud. Target tracking is carried out by using the center points of targets. The track of the target is initiated by investigating the normalized distance between the center points and connecting the points. The regular track obtained from the track initiation can be maintained by the target-tracking filter, which is commonly used in radar target tracking. The target-tracking filter is constructed to track a maneuvering target in a cluttered environment. The target-tracking algorithm including track initiation is experimentally evaluated in a sea-trial test with several boats.

• Journal of Navigation and Port Research
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• v.29 no.10 s.106
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• pp.897-906
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• 2005

The purpose of this research is to verify the strategic fitness and relevance of the distribution park for a hub port in Northeast Asia and to find a method to be a hub-port with a competitive edge. The strategic factor of distribution park development are policy, methodology and promotion method So these factors are analysed by structural equation model. The essential results of the research show that distribution park should be actually developed to produce value-added and to be port cluster.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2010.04a
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• pp.193-194
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• 2010

This study classify the every meshes in Busan metropolitan city, based on the heat density and cooling/heating ratio. As the result of evaluations on the heat density and cooling/heating ratio for the 3289 meshes, the number of meshes which needs more than 2.5 Tcal/mesh.year of heat density is 850(25.8%). The meshes that needs more than district and cooling index 1, which is normally and strongly requested to introduce the district cooling and heating system, is 188(5.7%).

• Journal of Navigation and Port Research
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• v.35 no.5
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• pp.445-454
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• 2011

According to financial hub related law of government, new financial hub in Busan will be differentiated from existing other financial hubs by reflecting regional characteristics as financial cluster and by connecting with business hub. Based on an ongoing busan international finance center in Munhyun innovation city. this study is focused on suggesting development methodes for international competitiveness of Busan international finance center considering of maritime-specialization connecting with citizen park and busan north port renewal districts. through the financial hub concept, types, be valid conditons, competitiveness and international case studies over the analysis of development conditions and a development plans for developing fosterage-programs suppementary and strategy, guidelines of physical developmentde direction.

• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.4
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• pp.408-414
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• 2018

Various studies have been conducted to reduce marine accidents. However, research on marine incidents is only marginal. There are many reports of marine incidents, but the main content of existing studies has been qualitative, which makes quantitative analysis difficult. However, quantitative analysis of marine accidents is necessary to reduce marine incidents. The purpose of this paper is to analyze marine incident data quantitatively by applying big data techniques to predict marine incident trends and reduce marine accident. To accomplish this, about 10,000 marine incident reports were prepared in a unified format through pre-processing. Using this preprocessed data, we first derived major keywords for the Marine incidents at sea using text mining techniques. Secondly, time series and cluster analysis were applied to major keywords. Trends for possible marine incidents were predicted. The results confirmed that it is possible to use quantified data and statistical analysis to address this topic. Also, we have confirmed that it is possible to provide information on preventive measures by grasping objective tendencies for marine incidents that may occur in the future through big data techniques.