• Journal of Korea Society of Industrial Information Systems
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• v.16 no.2
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• pp.65-72
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• 2011

In this paper, a real-time monocular vision based navigation system is developed for the disabled people, where online background learning and vector field histogram are used for identifying obstacles and recognizing avoidable paths. The proposed system is performed by three steps: obstacle classification, occupancy grid map generation and VFH-based path recommendation. Firstly, the obstacles are discriminated from images by subtracting with background model which is learned in real time. Thereafter, based on the classification results, an occupancy map sized at $32{\times}24$ is produced, each cell of which represents its own risk by 10 gray levels. Finally, the polar histogram is drawn from the occupancy map, then the sectors corresponding to the valley are chosen as safe paths. To assess the effectiveness of the proposed system, it was tested with a variety of obstacles at indoors and outdoors, then it showed the a'ccuracy of 88%. Moreover, it showed the superior performance when comparing with sensor based navigation systems, which proved the feasibility of the proposed system in using assistive devices of disabled people.

• The Journal of the Korea Contents Association
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• v.15 no.3
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• pp.57-67
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• 2015

The aim of this study was to categorize and analyze the patterns of the observation type in the experiential learning through the science museum for elementary gifted students in science. Ten science-gifted students were included and analyzed in this study and during experiential learning in the science museum, the participants freely expressed their observation of their own languages and all observations and dialogue were recorded. The results are listed below. The cognitive aspect, especially question and response activity without their personal opinion, was the most frequently used item. Among the affective aspects, item for 'recommendation' was often used. In accordance to observation type, most participants overall observed single object independently of time. Also, participants mostly observed objects visually using qualitative method without manipulation. Therefore verbal interaction through question might have a positive effect on frequency and diversity of observation. Project learning, such as particular exhibition hall, exploratory time of concentration by students, or study paper will be capable of creating a effective observation learning in order to induce a variety of observation of science gifted students in the experiential learning through the science museum.

• The Journal of the Korea Contents Association
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• v.7 no.11
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• pp.23-33
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• 2007

The collaborative filtering has used the nearest neighborhood method based on the preference and the similarity using the Pearson correlation coefficient. Therefore, it does not reflect content of the items and has the problems of the sparsity and scalability as well. the item-based collaborative filtering has been practically used to improve these defects, but it still does not reflect attributes of the item. In this paper, we propose the user and item based collaborative filtering using the classification property and Naive Bayesian to supplement the defects in the existing recommendation system. The proposed method complexity refers to the item similarity based on explicit data and the user similarity based on implicit data for handing the sparse problem. It applies to the Naive Bayesian to the result of reference. Also, it can enhance the accuracy as computation of the item similarity reflects on the correlative rank among the classification property to reflect attributes.

• Journal of the Korea Society of Computer and Information
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• v.25 no.5
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• pp.99-106
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• 2020

The scalability problem inherent in collaborative filtering-based recommender systems has been an issue in related studies during past decades. Clustering is a well-known technique for handling this problem, but has not been actively studied due to its low performance. This paper adopts a clustering method to overcome the scalability problem, inherent drawback of collaborative filtering systems. Furthermore, in order to handle performance degradation caused by applying clustering into collaborative filtering, we take two strategies into account. First, we use fuzzy clustering and secondly, we propose and apply a similarity estimation method based on user preference for movie genres. The proposed method of this study is evaluated through experiments and compared with several previous relevant methods in terms of major performance metrics. Experimental results show that the proposed demonstrated superior performance in prediction and rank accuracies and comparable performance to the best method in our experiments in recommendation accuracy.

• Journal of the Korean Society of Marine Environment & Safety
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• v.11 no.1 s.22
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• pp.1-9
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• 2005

The Judgement on a certain maritime accident accompany with punishment or recommendation to the examinee who was connected with that accident. It also gives quite a consequence to the Civil Trial relating with the maritime accident. In the Maritime Safety Tribunal System, the examinees can get assistance from Maritime Counselor. As it requires a lot of costs, it should be limited by economic condition of the examinees. In this Paper, with the consideration of the several kinds of Free Counsel System, Free Counsel System for Maritime Safety Tribunal was studied. The proposals are as follows; 1. To introduce the Mandatory Counselling and Court-designated Counselor System. The costs to be paid by government. 2. The same as above but the counselor to be designated among the staffs of the maritime organizations, then the costs to be paid by the organization which they belonged. 3. To establish Maritime Safety Tribunal Association which performs Monetary Assistance same as Korean Legal Aid Corporation.

• Journal of the Korean Society of Marine Environment & Safety
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• v.16 no.2
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• pp.195-200
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• 2010

Basing on the recommendation and guideline of IALA, Korean VTS authority made an instruction about the training and qualification of VTS operators, and three model courses for training have been performed at a training institute which has one VTS simulator. However, the simulator has not been enough to make training fully satisfactory because of several signs of limitations including inaccurate method for calculating ship's movement and inconvenient location for training. In this paper, a new simulator was proposed to make up for the weak points replacing the current simulator. The proposed simulator adopts mathematical model for calculating exactly ship's movement which heightens the effect of training with simulator. And also it can be used through Internet so as to make long-distance training possible without visiting the training center. The effectiveness and the convenience of training with the proposed simulator are expected to be improved.

• Journal of Convergence for Information Technology
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• v.10 no.4
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• pp.1-10
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• 2020

The performance of the personalized product recommendation system for offline shopping malls is poor compared with the one using online environment information since it is difficult to obtain visitors' characteristic information. In this paper, a mobile robot platform is suggested capable of recommending personalized advertisement using customers' sex and age information provided by Face API of MS Azure Cloud service. The performance of the developed robot is verified through locomotion experiments, and the performance of API used for our robot is tested using sampled images from open Asian FAce Dataset (AFAD). The developed robot could be effective in marketing by providing personalized advertisements at offline shopping malls.

• Special Issue of the Society of Naval Architects of Korea
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• 2008.09a
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• pp.46-53
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• 2008

Recently, the synthetic material stern tube bush has been applied by ship owner's requirement because the synthetic material has a merit. That is to say, when stern tube seal is damaged and sea water comes into stern tube, it can work without problem because of water lubricating property. However, the material also has a demerit of temperature rise problem when some factors meets on synthetic material, for example, not sufficient lubrication oil supply and not proper shaft alignment and so on. As known in the world, the RAILKO bush is rampant for synthetic material by some ship owner because of the above mentioned reason. However, the bush has several accidents on large container vessel. Unfortunately or fortunately our yard has a chance to apply the RAILKO bush owing to requirement of specific ship owner. Therefore, it is much more required to approach the accurate shaft alignment analysis. In line with this reason, we had a shaft alignment calculation considering hull deformation and hull flexibility (hull stiffness). Also, in the calculation, we had considered dynamic condition which is reflected he propeller thrust forces and moments and oil film stiffness on the shaft alignment calculation. According to he shaft alignment calculation, bearing slope was applied on the tern tube bush and was measured. The RAILKO bush should be applied the running in procedure according to maker's recommendation for performing the oil film on the bush surface. Finally, the vessels were delivered successfully without any problem with AILKO bush as shown on his paper.

• Journal of Digital Convergence
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• v.14 no.3
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• pp.55-62
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• 2016

Today, demand for job training of married immigrants is increasing. This research aims to propose developmental Edu-Tech based on the demand for education contents and the characteristics of multicultural family. Based on analysis such as FGI(focus group interview) and expert interview, this paper presents a four methods for development of EduTech for multicultural people, such as language skills, the recommendation technology of customized training contents, contents design based on gamification and user experience design. This research contributes to the direction of the method to use EduTech as a tool for gaps in education and welfare state.

• The Journal of the Acoustical Society of Korea
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• v.18 no.6
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• pp.77-83
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• 1999

H.263 is an international standard of ITU-T that can makes the service such as video phone, video conference in the transmission line less than 64Kbps. This recommendation draft has used motion estimation/compensation, transform coding and quantizing methods. TMN5 used for the performance estimation of H.263 has fundamentally used DCT in transform coding method and presented quantizer for quantizing the DCT transform coefficient. This paper is presenting adaptive quantizer effectively able to quantize DCT coefficient considering the human visual sensitivity while the structure of TMN5 is maintaining. As quantizer that proposed DCT-based H.263 could make transmit more frame than TMN5 in a same transfer speed, it could lower the frame drop effect. And the luminance signal appeared the difference of -0.3 ～ +0.7dB in the average PSNR for the estimation of objective image quality and the chrominance signal appeared the improvement in about 1.5dB in comparision with TMN5. As a result it can attain the better image quality compared to TMN5 in the estimation of subjective image quality.