• 대한조선학회논문집
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• 제57권3호
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• pp.160-167
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• 2020

A two-stroke diesel engine and a propeller normally adopted in large merchant ships are regarded as major ship vibration sources. They are directly connected and generate various excitation components proportional to the rotating speed of diesel engine. Among the components, the magnitude of two excitation components with the same frequency generated by both engine and propeller can be compensated by the adjustment of their phase difference. It can be done by the optimization of propeller assembly angle but requires a number of burdensome trials to find the optimal angle. In this paper, the efficient estimation method to determine optimal propeller assembly angle is proposed. Its application requires the axial vibration measurement in sea trial and the numerical vibration analysis for propulsion shafting which can be substituted by additional vibration measurement after one-trial modification of propeller assembly angle. In order to verify the validity of the proposed method, the phase difference between two fifth order excitation components generated by both diesel engine and propeller of a real ship is calculated by the finite element analysis and its result is indirectly validated by the comparison of axial vibration responses at intermediate shaft obtained by the numerical analysis and the measurement in sea trial. Finally, it is numerically confirmed that axial vibration response at intermediate shaft at a resonant speed can be decreased more than 87 % if the optimal propeller assembly angle determined by the proposed method is applied.

• 한국지리정보학회지
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• 제10권2호
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• pp.164-171
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• 2007

본 연구는 GIS공간분석기법과 Huff의 확률모형을 이용하여 근린생활권중심의 상권분석을 수행하였다. 연구에 사용된 기본도는 청주시 복대동을 대상으로 하여 업종, 세대수 등을 현장 조사하여 구축하였으며, 기 구축된 LMIS에 있는 연속지적도를 활용하였다. 분석에서는 커널밀도함수(Kernel Density Function)와 최근린지수(Nearest Neighbor Index)를 활용하여 근린생활권내 점포분포 중심권역을 설정하였다. 상권분석을 수행하기 위하여 설정된 중심권역에 따라 중심지(점)와 규모를 산출한 후 상권분석의 모형인 Huff 확률모형에 적용하여 중심권역별 상권을 추출하였으며, 추출된 상권을 지도로 도식하였다. 따라서 본 연구에서는 GIS 공간분석기법 중 커널밀도함수와 최근린지수를 통해 Huff 확률모형에 적용할 수 있는 방법을 제시하였다. 이러한 방법들을 이용함으로써 보다 정확하게 상권분석을 할 수 있으며, 향후 창업하고자 하는 소상공인들에 도움이 될 수 있으리라 사료된다.

• 수산해양교육연구
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• 제2권1호
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• pp.29-35
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• 1989

It is indispensable for the marine officers who are engaged in the international voyage to make command of maritime English fluently. The Marine Officers Act in Korea which is under ammending in 1989 prescribes the proportion of maritime Englishin English examination is made to be 60% for the 4th and 5th class marine officer-license examination. A concrete syllabus or content of maritime English is not established yet with the exception of a general prescription of minimun knowledge required for certification of marine officers in the IMO/STCW Convention. The authors, who rewrote the maritime English textbook for the course of the fisheries high, schools and the merchant marine high schools, settled the syllabi of nautical English and marine engineering English for the course as follows : 1. The syllabus of nautical English, includes maritime English readings, the IMO English dialogue on port entry, writing of logbooks, night order books, and docking and repair specifications. 2. The syllabus of marine engineering English includes maritime English readings, dialogue on oil supply, writing of engine logbooks and oil record books, standing orders, and docking and repair specifications. The authors propose that the realm of these class marine officer-license examination on maritime English should be limited within in the above mentioned textbook. As maritime English is made to be included in the 4th and 5th marine officer liscence examination since 1989, high schools concerned need to reform the curricula to complete at least 6 units for this subject. On the other hand, the competent authority of this examination must secure questions as much as possible to promote the reliability of them.

• International Journal of Ocean System Engineering
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• 제2권4호
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• pp.239-243
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• 2012

The cylinder liner of a low speed engine is one of the most important parts of the marine diesel engines used in merchant ships. However, a sufficient degree of precision in the manufacturing method for these cylinder liners has never existed. Conventional honing stones have always been used for machining large marine cylinder liners. Therefore, it is necessary to develop a honing process that optimizes the honing characteristics. In this study, a CBN honing stone was manufactured to improve the honing performance for a cylinder liner and shorten the processing time, and machining experiments on a practical cylinder liner were carried out. Then, a comparison was made between the CBN honing and honing with a conventional GC stone using parameters such as the honing time, machining quantity, and honing cost. As a result, for a #60 CBN stone, the machining amount was significantly improved compared to the conventional one by about $1.1{\mu}m$/min, and in respect to the machining cost, a reduction of about 57% was achieved. However, an improvement in the process with a #800 CBN stone could not be expected because it did not show a significant difference compared to the case of the existing stone. From the above results, if the liner were honed using a CBN honing stone, the rough machining and intermediate processing during an early stage of the honing process were excellent compared to the conventional one. However, we could not find a significant difference in the case of finish honing.

• 보험의학회지
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• 제1권1호
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• pp.133-139
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• 1984

In the 2,218 healthy cases-male 1,574 female 644-who were conducted serum examination from May 1st 1983 to November 1st 1983 by the medical selection of Dae Han Kyouk life insurance Co., the results which investigated the HBsAg by using the Reverse Passive Hemagglutination(RPHA) method are as follows; 1. The number of 167 from 2,218 cases proved to be positive, showing 7.52%, the number of 143 from 1,574 male positive, showing 9.08%, and the number 24 from 644 female positive, showing 3.73%. The positive rate of the male was indicated by 5.36% higher than that of the female as the former marked 2.4 times higher distribution than the latter. 2) The positive rate by the type of occupations appears as follows; The highest positive rate group is that of discharger from military service in 1983, the number of 70 from 736 persons marking 9.51% and the next is the merchant 8.79%(8/91), employee of a company markes 8.53%(44/516), high school boy 7.69%(19/247), house wife 5.71%(10/210), carrier woman 3.45%(10/290) and the group of the high school girl records the minimum rate of all, 3.13%(4/128). 3. The positive rate by the age group appears as follows; The highest rate group is that of 31 to 35 years, marking 9.80% positive rate, and the next is $26{\sim}30$(9.3%), $21{\sim}25$(8.01%), $41{\sim}45$(6.96%), $36{\sim}40$(6.9%), those below 20(5.99%), 46 to 50 years shows the minimum rate of all(2.94%) Among the male case, 26 to 30 years shows the highest positive rate by 10.59% and female, 31 to 35 years shows the highest rate by 7.89%. 4. The positive rate by the blood type represents as follows; Blood type A shows 7.30%, type B 7.17%, type O 6.11% and type AB indicates 5.88% in order.

• 해양환경안전학회:학술대회논문집
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• 해양환경안전학회 2004년도 추계학술발표회
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• pp.137-141
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• 2004

선체구조는 기본적으로 판부재의 조합으로 이루어져 있으며, 이러한 판부재는 하중분담 능력에 따라서 전체적인 구조의 강도에 른 영향을 미치게 된다. 또한 각 구조적인 판부재는 개별적으로 거동하는 것이 아니라 전체적인 구조와 연속적으로 작용하게 된다. 선박구조물은 강구조물과 해양구조물에서와는 달리 고정도의 부정정 구조물로 구성되어 있으며 이러한 구조물의 거동을 정확하게 규명하기 위해서는 복잡하게 구성되어 있는 선체판넬 구조를 단순화시켜서 해석에 적용하여야 한다. 본 연구에서는 선체판넬구조의 모델링영역에 따른 최종강도 거동의 차이를 분석하여, 가장 합리적인 모델링영역을 도출하고자 한다. 사용된 해석모델은 실제 상선의 이중저구조에서 사용되는 판넬에서 채택하였으며, 유한요소해석 모델링 시 3가지 서로 다른 해석영역을 제시하여 적요하였다. 본 연구의 목적은 일축압축하중이 작용하는 보강판넬구조에서 서로 다른 모델링영역을 갖는 보강판에서의 최종강도 거동을 분석하여 최적의 해석모델링 영역을 찾는 것이다.

• 대한지역사회영양학회지
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• 제15권5호
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• pp.679-686
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• 2010

The purpose of this study is to monitor genetically modified bean sprouts at traditional markets in Seoul and to investigate perception of traditional market merchants and high school students on genetically modified organisms (GMOs). We analyzed 30 bean sprouts that were selected at 11 traditional markets in Seoul using the method of polymerase chain reaction (PCR). Also, we compared perception of GMOs between merchants (n = 30) and students (n = 126). Knowledge test about GMOs was performed by students. The result of PCR, 16.7% of bean sprouts were confirmed as GM bean sprouts (n = 5). Students had significantly more exposure to information about GMOs than merchants (p < 0.05). Major information sources about GMOs were from mass media (television, newspaper and radio). About half of subjects were not aware that they eat GMOs and GMOs are sold to consumers. Only 17.3% of subjects had constant eating intent for GMOs after perceiving foods that he/she usually eats are GMOs. 51.3% of subjects had willingness to purchase GMOs if GMOs have same quality and lower cost than natural foods. 37.2% of subjects thought that GMOs would be harmful to humans. Students had more positive perception of GMOs' side effects than merchants (p < 0.01). There was no merchant who knew labeling of GMOs. 19.1% of students knew labeling of GMOs. Students' mean percentage of correct answers of six questions about GMOs was 45.2%. Therefore, providing adequate information about GMOs is needed for consumer's choice whether to purchase GMOs or not.

• 한국IT서비스학회지
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• 제16권4호
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• pp.33-46
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• 2017

Increasing popularity of smartphone is creating many changes in payment market sector also. The new fin-tech and simple mobile payment service have provided convenience as well as various benefits and value-added services to create new payment culture. However, the infrastructure of offline shops is too poor for users to use the simple mobile payment services in Korea. There are several reasons why the support of simple mobile payment services by offline shops has reached the limit in Korea. They include the reluctance of shop owners due to highly priced devices, the failure of NFC of the leading offline payment infrastructure to support iOS, the services that are biased to the specific manufacturers and smartphones (Samsung Pay and LG Pay), prefer large shops (SSG Pay and L PAY), and focus on online transactions. This study used the Bluetooth technology that is the standard feature built in all smartphone to expand the offline shops that accept the simple mobile payment services ensuring universality and scalability from the convenience of customer's and service provider's aspects. Applying the same payment scene as the existing NFC payment method from the user's aspect and the Bluetooth technology from the service provider's aspect enables support of all smartphones and offering value-added services such as electronic receipt and promotions through the large-capacity bidirectional data transfer. This study is intended to review the simple mobile payment services in Korea and other countries, propose the simple mobile payment service model for Korea by analyzing the Bluetooth technology and preceding studies of payment services using BLE technology, and develop the pilot system using the BLE technology to verify the proposed system with actual shops.

• 한국해양공학회지
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• 제22권3호
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• pp.82-88
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• 2008

The diesel engine of the merchant ship has been aperated in severe environments more and more, because the temperature of the exhaust gas of a combustion chamber is getting higher and higher with increasing use of heavy oil of law quality, due to the significant increase in the price of oil in recent some years. As a result, the degree of wear and corrosion between exhaust valve and seat ring is more serious compared to other engine parts. Thus the repair welding of exhaust valve and seat ring is a unique method to prolong the life of the exhaust valve, from an economical point of view. In this study, the corrosion property of both weld metal and base metal was investigated using electrochemical methods such as measurement of corrosion potential, cathodic and anodic polarization curves, cyclic voltammogram, and polarization resistance in 5% H2SO4 solution. The test specimen was a part of an exhaust valve stem being welded as the base metal, using various welding methods. In all cases, the corrosion resistance as well as hardness of the weld metal zone was superior to the base metal. In particular, plasma welding showed relatively good properties for both corrosion resistance and hardness, compared to other welding methods. In the case of DC SMAW (Shielded metal arc welding), corrosion resistance of the weld metal zone was better than that of the base metal, although its hardness was almost same as the base metal.

• 동아시아식생활학회지
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• 제22권1호
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• pp.75-87
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• 2012

We investigated the physicochemical properties, pasting characteristics on the rapid visco analyzer, dough characteristics on a mixograph, product characteristics, and attributes of color and hardness of products made from a wheat bagel premix and rice bagel premix according to storage period and temperature. The pH and moisture content of stored rice bagel premix and wheat bagel premix, significantly decreased, depending on the storage temperature and time. The average of water retention capacity, alkaline water retention capacity, sedimentation value, and pelshenke value all significantly decreased temperature increases and increasing storage time. he initial pasting temperature and breakdown depending on the storage temperature and time showed a significant difference, but peak viscosity and setback with increasing storage time and temperature were not significantly different. The initial pasting temperature did not significantly affect the rice bagel premix. The midline peak time and band at 8 min of mixing time of the wheat bagel premix and rice bagel premix did not differ significantly. In product attributes, the cost of wheat bagel premix rice bagel premix and the L, a, and b value in color of wheat bagel premix showed significant difference. The hardness of wheat bagel premix according to storage time and the hardness of rice bagel premix depending on storage temperature significant difference. Therefore, storage time and temperature of wheat bagel premix and rice bagel premix and does not show significant differences. merchant can get regular and consistent, it is expected to lead to the promotion of rice consumption. Futhermore, research on better method to improve it's characteristics instead of wheat bagel premix is expected to.