• 수산해양기술연구
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• 제53권4호
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• pp.337-348
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• 2017

The tension of warp from trawler and sea-floor contact can generate tilt and wake turbulence around otter boards. Preliminary measurements of otter board tilt and 3-D flow velocity during bottom trawl operations were taken using a vector instrument to investigate the effects of wake turbulence at the trailing edge of the otter board. Tilt data (i.e., yaw, pitch, and roll) at 1 Hz and flow data (velocities in the towing, lateral, and vertical directions) at 16 Hz were analyzed to determine their periods and amplitudes using global wavelet and peak event analyses. The mean period (${\pm}standard$ deviation) of the tilt from the peak event analysis ($5{\pm}2s$) was longer or double than that of flow velocity ($3{\pm}2s$). The two periods also had a significant linear relationship. The turbulence rate of flow was 30-50% at the trailing edge and was closely related to roll deviation. The frequency of phase difference ratios (i.e., peak time differences between tilts and flow periods) was significantly different from random occurrence in two trials, possibly due to side tidal effects. However, in the other trials, flow peaks were random, as shown by the even peak times between tilts and flows. Future studies should focus on reducing tilt variation, wake turbulence, and bottom contact to stabilize otter board motion.

• 수산해양교육연구
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• 제26권1호
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• pp.223-235
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• 2014

The purpose of this study is to investigate school administrators' perceptions of school evaluation, examining the current situation in the hope of finding solutions to the problems caused by current evaluation. The subjects of this research were consisted of 230 middle and high school administrators in Busan. The instrument used for the study were the questionnaire included 27 questions concerning the current situation, the problems and improvements of school evaluation. The results of this study were as followed: (1) school administrators generally have a positive attitude toward school evaluations. But, they thought need to enhance their leadership qualities so that teachers can feel more positive about participating in school evaluation. (2) school administrators have to show more of an interest in the planning, performance and the use of the results of evaluation. (3) to enhance the quality of teaching practices in school they have to improve their methods for providing feedback of the results of evaluations. (4) the biggest problem related to school evaluation is the lack of quality and professional knowledge of the evaluation teams. And each school develops a unique curriculum and focuses on the improvement of instruction methods.

• 수산해양교육연구
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• 제25권1호
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• pp.260-273
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• 2013

This study aims to reflect experts' opinions in analyzing a design thinking as foundation of multidisciplinary education. For this purpose, a delphi survey was conducted with 20 experts in three sessions from May 1 to June 25, 2012. To analyze the collected data, descriptive statistics, including frequency, percentage, the mean, and standard deviation were implemented, and internal reliability test on the survey instrument was carried out for statistical processing. The main results are as follows : First, the delphi analysis on intuitive thinking of design thinking suggested 7 items(to pursue the possibility of outside, to pursue the possibility of applying new forms of technology, content planning, facing a complex real-world phenomena etc.). Second, the delphi analysis on logical thinking of design thinking suggested 7 items(executed repeatedly, reasoning and verification, artificial intelligence, a decision support system etc.) Third, the delphi analysis on subjective thinking of design thinking suggested 9 items(user experience measuring, user satisfaction ratings, user requirements analysis, user interface design, behavioral responses of the human etc.). Fourth, the delphi analysis on objective information of design thinking suggested 8 items(information management system, simulation, production process, information exchange and sharing etc.). According to the results of the delphi analysis, design thinking can be seen as the foundation of multidisciplinary education. Suggestions were made for discussion about the main results and further researches.

• 수산해양교육연구
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• 제19권2호
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• pp.288-300
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• 2007

The study was designed to lay the ground for effective guidance toward adaptive coping behavior by finding out differences in ego-resiliency in terms of personality types in the Murphy-Meisgeier Type Indicator for Children(MMTIC). For the study, personality types and ego-resiliency of 180 fifth- and sixth-grade students from 3 elementary schools located in Busan were measured. The instrument for personality types was MMTIC, which was developed by Meisgeier and Murphy in the US in 1990 and standardized in Korea in 1993 by Jungtaek Kim and Hyesook Shim. In order to measure Ego-Resiliency, Block & Kremen(1996)'s Ego-Resiliency scale translated and remodified by Sungkyung Yoo(2004) was used. The collected data were analyzed using ANOVA. The study found the followings: Firstly, according to the children's preference for personality types, participants' ego-resiliency scores appeared significantly higher in 'Extraversion', 'iNtuition', and 'Feeling' than in 'Introversion', 'Sensing', and 'Thinking' respectively. There was no significant difference in the score between in 'Judging' and 'Perceiving'. Secondly, according to function types of MMTIC, the participants' ego-resiliency score in 'iNtuition-Feeling' type showed the highest among scores in the other three types. The score in 'iNtuition-Feeling' type was significantly higher than 'Sensing-Thinking', 'Sensing-Feeling', and 'iNtuition-Thinking' type respectively.

• 수산해양교육연구
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• 제19권1호
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• pp.91-100
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• 2007

The purpose of this study was to compare personality existed in the populations of the mentally retarded with and without Down syndrome. For this purpose, two research questions were proposed. (a) Is there any difference of personality existed between two groups? (b) Is there any difference of sub-personality existed between two groups by disability degree? Participants in this are 159 people with mental retardation(the mentally retarded with Down syndrom: 82, the mentally retarded without Down syndrom : 77) in P and S cities. First of all, the reliability in measurement instrument was verified through a pre-study. For the first research question, t-test was used. And two way ANOVA was used to investigate the second research question. The results of this study were as follows:First, according to the result of t-test, there were significant differences of personality scores between two groups. And there were significant differences between the mentally retarded with and without Down syndrome regard to expectation of success, outerdirectedness, positive or negative responding tendency, curiosity among sub-personality factors. Second, the result of the two way ANOVA analysis, no meaningful statistically difference in personality by degree of the impairment. But It showed difference regard to effectancy motivation, expectation of success, curiosity among sub-personality factors between the mentally retarded with and without Down syndrome by impairment degree.

• 수산해양교육연구
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• 제23권4호
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• pp.648-661
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• 2011

The purpose of this study was to examine the school parent and student's perception of Practical Arts and Technology Home Economics and to suggest plan to school parent of multicultural and learning disability families. The subjects of this study were elementary and secondary teachers who teaching Practical Arts or Technology Home Economics. The instrument of this study was questionnaire including five sections: influence on students by Practical Arts and Technology Home Economics, interest in Practical Arts and Technology Home Economics to school parents, school support with learning ability improvement, school parents support with home in Practical Arts and Technology Home Economics, data form of school parents support with home in Practical Arts and Technology Home Economics. The findings of this study were as follows; Sociality development of students is influential by Practical Arts and Technology Home Economics. School parents and students believe important subjects in Practical Arts and Technology Home Economics. Teachers ask for support with learning ability improvement for practical training space and programs in Practical Arts and Technology Home Economics. School parents ask for support with learning ability improvement of programs of teaching learning method for home education on Practical Arts and Technology Home Economics.

• 센서학회지
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• 제31권1호
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• pp.64-68
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• 2022

Herein, we propose a LoRaWAN-based small draft system that can measure the ocean current flow (speed, direction, and distance) in real time at the request of the Coast Guard to develop a device that can promptly find survivors at sea. This system has been implemented and verified in the early stages of rescue after maritime vessel accidents, which are frequent. GPS signals often transmit considerable errors, so correction algorithms using the improved triangulation method algorithm are required to accurately indicate the direction of currents in real time. This paper is structured in the following manner. The introduction section elucidates rescue activities in the case of a maritime accident. Chapter 2 explains the characteristics and main parameters of the GPS surveying technique and LoRaWAN communication, which are related studies. It explains and expands on the critical distance error correction algorithm for GPS signals and its improvement. Chapter 3 discusses the design and analysis of small draft buoys. Chapter 4 presents the testing and validation of the implemented system in both onshore and offshore environments. Finally, Section 5 concludes the study with the expected impact and effects in the future.

• 해양환경안전학회지
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• 제27권6호
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• pp.898-904
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• 2021

본 연구에서는 강화되는 황산화물 및 입자상물질의 배출규제를 만족시키기 위한 후처리장치로 습식전기집진기에 대한 실험적 연구를 수행하였다. 실험을 위해 선박용 중유(HFO, 황함유량 약 2.1%)를 연료로 사용하는 선박용 4행정 디젤엔진(STX-MAN B&W)을 활용하였으며, 연돌에 설치된 습식전기집진기 입/출구에서 측정을 실시하였다. 미세먼지 측정을 위해서는 광학식 계측기(OPA-102) 및 중량농도측정방식(Method 5 Isokinetic Train)을 이용하였으며, 황산화물 계측을 위해서는 FT-IR(DX-4000)을 사용하였다. 엔진부하는 50%, 75%, 100%로 변화시키면서 실험을 실시하였다. 실험 결과로, 엔진부하가 50%에서 100%로 변화함에 따라 미세먼지 저감 효율은 모든 부하 조건에서 94~98% 정도의 높은 저감 효율을 나타내었다. 추가적으로 습식전기집진기 퀜칭존에서 배기가스의 온도를 낮추는 과정 중 세정액에 의한 이산화황(SO₂) 저감을 확인할 수 있었으며, 저감율은 엔진부하에 따라 55%~81%로 확인되었다.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2004년도 학술대회지
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• pp.55-60
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• 2004

In this study, the configuration and tension of a towing cable for side-scan sonar are predicted in an ambient flow and at an unsteady towing condition. The governing equation of three-dimensional dynamic analysis for a flexible cable is solved using a finite difference method. We successfully predict the configuration and tension of a side-scan sonar and designed the towing system. It is found in static analyses that the side-scan sonar must be towed to keep a its stable depth at a reasonable speed. The study also reveals in the transient analyses that the dominant component affecting the top tension is the tangential drag force for the larger towing speed than the critical speed, and the self weight of a towed instrument for the smaller towing speed than. It should be maneuvered for a towing vessel with good consideration for the impact effect in a cable due to tension peak when a towing speed is suddenly increase. The developed program can be applicable for three-dimensional dynamic analysis of a towing system for various marine survey instruments.

• Journal of Advanced Marine Engineering and Technology
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• 제39권1호
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• pp.32-44
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• 2015

일반적으로 선박의 운동은 이동운동과 회전운동의 결합으로 이루어진다. 특히 대형 크루즈 선박과 광케이블 포설용 선박, 다이버용 선박 등 특수 선박은 자동 접이안이나 설정된 경로 등을 따라 선수방향의 변화 없이 여러 방향으로 이동만 하는 운동을 재현할 수 있어야 한다. 본 논문에서는 다 추력장치를 가진 선박을 대상으로 조이스틱 명령 기반의 이동운동제어를 실현할 수 있는 통합제어시스템의 구성방법을 제안하며, 이를 실현하기 위하여 필요한 속도명령 생성방법과 대응하는 운동변수 및 이들이 가져야 하는 기준 값 생성방법을 제안한다. 또한 정의된 운동변수의 기준 값을 추종하기 위한 다양한 알고리즘 구성에 대하여 논한다. 또한 통합제어시스템 시뮬레이션 프로그램을 작성하고 이를 토대로 다양한 이동운동 명령에 대한 모의실험을 수행한 후, 시뮬레이션 결과를 바탕으로 제안된 방법의 유효성을 검증한다.