• Journal of Mechanical Science and Technology
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• 제20권6호
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• pp.849-863
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• 2006

IBM (Immersed Boundary Method) with feedback momentum forcing was applied to stationary and moving bodies. The capability of IBM to treat the obstacle surfaces, especially with moving effect has been tested for two dimensional problems. Stationary and oscillating cylinders were simulated by using IBM based on finite volume method with Cartesian coordinates. For oscillating cylinder, lateral and vertical motions are considered, respectively. Present results such as time histories of drag and lift coefficients for both stationary and oscillating cases are in good agreement with previous numerical and experimental results. Also, the instantaneous wake patterns of oscillating cylinder with different oscillating frequency ratios well represented those of previous researches. More feasibility study for IBM has been carried out to two oscillating cylinders. Drag and lift coefficients are presented for two cylinders oscillating sinusoidally with phase difference of $180^{\circ}$.

• Ocean Systems Engineering
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• 제2권4호
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• pp.271-287
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• 2012

Due to its large size, a ship is first divided into scores of blocks and then each block is constructed through various shops, such as the assembly shop, the painting shop, and the outfitting shop. However, each block may not be directly moved to the next shop and may be temporarily laid at a block stockyard because the working time in each shop is different from each other. If blocks are laid at the block stockyard without any planning, the rearrangement of the blocks by a transporter is required because the blocks have the different in and out time. In this study, a block layout method based on the genetic algorithm was proposed in order to minimize the rearrangement of the blocks in the block stockyard. To evaluate the applicability of the proposed method, it was applied to simple layout problems of the block stockyard. The result shows that the proposed method can yield a block layout that minimizes the total relocation cost of moving obstacle blocks in the block stockyard.

• 대한임베디드공학회논문지
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• 제16권6호
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• pp.293-297
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• 2021

This paper presents how to create a 3D map and solve problems related to generating a global path planning for navigation. Map creation and localization were performed using the RTAB-Map package to create a 3D map of the environment. In addition, when the target point is within the obstacle space, the problem of not generating a global path was solved using the asr_navfn package. The performance of the proposed system is validated through experiments with a wheelchair-type robot.

• International journal of advanced smart convergence
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• 제8권2호
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• pp.30-38
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• 2019

Recently, the spread of personal mobility has been rapidly increasing due to the development of environmentally friendly alternative transportation means. In addition, the level of battery technology is also rapidly developing, accelerating the popularization of personal mobility. Such personal mobility has convenience of location transfer, amusement, and high portability compared to other transportation devices. Most personal mobility, however, is made up of small wheels, which cannot overcome obstacles such as rugged roads or obstacles on the road. In this paper, to solve these problems, we tried to devise a device that can easily overcome obstacles by combining wheels with small moving means. The wheel size can be mounted on the front wheel of the small moving means in a protruding manner so that obstacles can be encountered before the front wheels and the safety and ride comfort of the running can be improved.

• International Journal of Computer Science & Network Security
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• 제22권6호
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• pp.163-171
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• 2022

Online services are widely spread, and their use increases day by day. As COVID-19 spread and people spent much time online, fraud scams have risen unexpectedly. Manipulation techniques have become more effective at swindling those lacking basic technological knowledge. Unfortunately, a user needs a quorum. The interest in preventing scammers from obtaining effective quality service has become the most significant obstacle, increasing the variety of daily Internet platforms. This paper is concerned with analyzing purchase data and extracting provided results. In addition, after examining relevant documents presenting research discussing them, the recommendation was made that future work avoids them; this would save a lot of effort, money, and time. This research highlights many problems a person may face in dealing with online institutions and possible solutions to the epidemic through theft operations on the Internet.

• 시스템엔지니어링학술지
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• 제20권spc1호
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• pp.108-118
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• 2024

As shared electric kick scooters spread to cities worldwide as a result of the proliferation of personal mobility, they have emerged as a significant social issue, impacting pedestrian and user safety, as well as urban aesthetics. In this study, we propose solutions to the unique problems associated with shared electric kick scooters, such as illegal parking, charging, and redistribution. Furthermore, we present research on supplementary services utilizing electric kick scooters in urban areas to enhance citizen safety and user satisfaction through the development of an autonomous electric kick scooter system structure and operational strategies. We suggest a low-cost autonomous electric kick scooter structure and propose AI processing, sensor fusion, and system operation methods to add autonomous capabilities to affordable electric kick scooters. Additionally, we propose operational systems and related technologies for offering various supplementary services.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2016년도 추계학술대회
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• pp.224-226
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• 2016

기술의 발전과 민간수요 급증으로 '무인 자율화', '이동체' 특성이 결합된 무인이동체 신시장이 급성장하고 있다. 현재 일부 국가들이 시범주행을 허용하고 있으나, 자율주행차의 정식 운행을 제도화 한 나라는 없다. 기존 차량의 경우에도 후방감지기의 잦은 오작동이나, 후방카메라의 사각지대 또는 운전자의 부주의 때문에 안전사고가 자주 일어나고 있다. 이러한 사소한 결함들을 보완이 되어야 자율주행차, 소형드론의 상용화를 위한 관련 규제를 완화 할 수 있을 것이다. 본 논문에서는 기존의 이동체에서 사용되었던 초음파, 레이저 센서와는 다르게 깊이 카메라를 이용하여 거리측정을 시도해보려 한다. 깊이 카메라는 레이저나 적외선을 객체나 대상 영역에 비추어 되돌아오는 광선을 받아 시간 차이를 계산하는 TOF 방식으로 거리 정보를 계산한다. 이런 카메라는 CCD 카메라 영상 화소 단위로 깊이 정보를 얻을 수 있어 실시간 깊이 정보를 모으는 데 활용할 수 있다. 이런 실시간 깊이 정보들을 이용하여 앞서 말한 문제점을 해결하고, 거리측정을 통한 장애물 회피 시스템 설계를 제안한다.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• 제29권1호
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• pp.7-13
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• 2018

Objectives: Problem behaviors pose a great obstacle to daily functioning in children with neurodevelopmental deficits and are an important target for treatment. In this study, we translated the Behavior Problems Inventory (BPI)-01 into Korean language and tested its psychometric properties. Methods: We attained the approval of the BPI author and performed standard translation-back translation. Then, professional caregivers examined appropriateness according to cultural and situational contexts in order to make necessary modifications of the Korean version of the BPI. Results: The BPI-01, Korea-Scales of Independent Behavior-Revised (K-SIB-R), and Child Behavior Checklist were completed for 98 autistic spectrum disorder or intellectual development disorder participants (mean age=28.3, standard deviation=7.3, range=10.1-51.7). The inter-rater reliability of the BPI-01 was found to be high (r=0.992-1.000). As for the results for concurrent validity for subscale items of BPI-01 and scales of SIB, correlations between SIB and BPI-01 subscales were statistically significant (r=0.357-0.672). Discussion: The Korean version of the BPI-01 showed good psychometric properties with high reliability and sufficient convergent validity. Further examination of the validity of BPI-01 should be carried out with inclusion of younger aged children and a closer look at less frequently occurring symptoms.

• 수산해양교육연구
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• 제29권1호
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• pp.270-285
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• 2017

This study is about the solution to solve the problem - aging of fisheries worker and exodus of young adult from fisheries. We tried to find out internal improvements which are necessary for overcoming issues. After that, research about inducements and institutional improvements to drive internal improvements has done. and Current policies of Korea for securing workforce in fisheries were examined especially for Gyeongsangnam-do by literature investigation and survey The main purpose of this study is, problems of policy in order to secure Fisheries managers, identify practical obstacle and the activities and management activities performance of training education. and it is to provide evidence to policy improvement. To achieve the purpose of this study, conducted studies are as below. This study is to investigate the educational performance of Fisheries managers and its impact on their business performance using SEM and SEM-Moderate-effect. In terms of the amount of impact on business performance, the level of educational achievement and management activity outcomes had the most impact followed by excellence of educational condition and programs distinction. Therefore, in order to inspire the motivation for learning and communicate the importance of such education to Fisheries communities, there is a need to introduce a variety of methods, professional facilities. The purpose of this research is to define the problems of the Fisheries Census of Korea and to make better policies for improvement. In order to complete the purpose, the research team has firstly conducted a survey in the six regions to reinvestigate the yes or no for accuracy of the primary data related to the Fisheries Census. Moreover, the team has defined the problems of the Fisheries Census through conducting a survey for the experts and users of the fisheries statistics. Also, the team has derived the short/long term improvement of Fisheries Census through out this survey.

• 정보처리학회논문지D
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• 제11D권2호
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• pp.351-360
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• 2004

대부분의 이동 에이전트는 순차적인 노드 이주 방식에 의하여 다수의 이동 에이전트 시스템들로 이주된다. 하지만, 이러한 이주방식에서는 호스트의 결점이나 장애 등과 같은 문제가 발생하였을 경우, 이동 에이전트가 무한 대기나 고아 상태에 빠지므로 노드들 사이의 네트워크 소요시간이 증가하기 때문에 실제 다른 분산 기술들을 사용한 것만큼의 기대효과를 얻기가 어렵다. 따라서 이러한 문제를 해결하기 위한 연구들이 진행되어 왔지만 대부분 수동적 라우팅 테이블을 기반으로 노드의 이주를 결정하거나 문제가 발생된 호스트를 선회하는 방법이므로 실제 전체적인 네트워크 소요시간을 감소시키기 위한 연구는 아직 미흡하다. 본 논문에서는 이동 에이전트가 이동 에이전트 시스템들로 이주시 네트워크 소요시간을 감소시키기 위하여 네이밍 에이전트의 메타-테이블에 등록된 구현 객체 정보를 기반으로 능동적 라우팅 테이블을 설계한다. 또한 사용자의 키워드에 대하여 메타-테이블에서 일치하는 객체 참조자의 정보와 수에 따라 다수의 에이전트 객체를 복제한다. 복제된 객체는 이동에이전트 시스템들로 병렬 이주되며, 최소의 네트워크 소요시간을 제공한다.