• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.6B
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• pp.633-639
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• 2006

The validity of the existing formulas for the estimation of reflection coefficient of waves due to perforated wall is investigated using the result of hydraulic experiments conducted with perforated walls of various thickness. The result shows that, when the wall is thick, the energy loss coefficient is reduced to 62% of the value evaluated using the existing formula for sharp-crested orifice. The result also shows that the length of inertia resistance increases linearly as the thickness of the wall increases. The width of chamber to achieve the minimum reflection of waves decreases as the length of inertia resistance increases. Thus, the result found in the present study can be usful for the design of perforated wall.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.60 no.2
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• pp.186-193
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• 2024

Most fishing nets used in fish cage aquaculture are made of synthetic fibers such as polyamide (PA) and polyethylene (PE). Therefore, it is challenging to maintain the internal volume of the fish cage due to biofouling, which can increase the load on the cage or reduce dissolved oxygen levels by impeding smooth current flow. To address this issue, research has been conducted to replace conventional synthetic fiber cage nets with brass nets, demonstrating certain benefits such as improved productivity and ease of fish cage management. However, given the need for a more thorough examination of brass fishing net weaving technology and performance, this study assessed the optimal weaving method for brass fishing nets to be used in fish cages. Additionally, it provided essential data for the practical application of brass fishing nets by evaluating their weight, tensile strength, elongation, fatigue resistance, and wear resistance. The study concluded that weaving brass fishing nets using the chain link method ensures durability, ease of installation, and compact storage in a scroll-like form. Moreover, due to their superior fatigue and wear resistance properties, brass nets can offer increased utility if appropriate net diameter and length are selected to compensate for their higher weight per unit area and relatively higher cost compared to existing fiber fishing nets.

• Journal of the Korean Society for Marine Environment & Energy
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• v.8 no.1
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• pp.46-52
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• 2005

A marine environmental information system (MEIS) useful for optimal route planning of ships running in the ocean was developed. Utilizing the simulated marine environmental data produced by the European Center for Medium-Range Weather Forecasts based on global environmental data observed by satellites, the real-time forecast and long-term statistics of marine environments around planned and probable ship routes are provided. The MEIS consists of a land-based data acquisition and analysis system(MEIS-Center) and a onboard information display system(MEIS-Ship) for graphic description of marine information and optimal route planning of ships. Also, it uses of satellite communication system for data transfer. The marine environmental components of winds, waves, air pressures and storms are provided, in which winds are described by speed and direction and waves are expressed in terms of height, direction and period for both of wind waves and swells. The real-time information is characterized by 0.5° resolution, 10 day forecast in 6 hour interval and daily update. The statistic information of monthly average and maximum value expected for a return period is featured by 1.5° resolution and based on 15 year database. The MEIS-Ship include an editing tool for route simulation and the forecasting and statistic information on planned routes can be displayed in graph or table. The MEIS enables for navigators to design an optimal navigational route that minimizes probable risk and operational cost.

• International Commerce and Information Review
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• v.14 no.1
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• pp.47-65
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• 2012

Africa has got largely attention from around the world and industrial advanced countries mainly have focused their interest on the continent for the purposes of natural resources development or economic cooperation. Such is in part for their exploiting new logistics. Central America, Oceania and Africa are together now emerging as a new mecca for resources development and global logistics. Considering that Western countries are heavily investing in and preoccupying both social overhead infrastructure and logistics in Africa, it is expected that it will be new opportunities for domestic logistics companies. This research is focused on studying strategies for logistics companies to open Africa, especially Northern African market. For this, the method of questionnaire is applied for related companies. And it also considers proper time for the opening the market, how to enter, geographical market range and interests of countries there. From the result, it is important the timing for entering the market, which means competitive edge gets better with fast making inroads into the market. And strategic alliance is revealed more effective. In addition, geographical market range is another important factor in low infrastructure of logistics in Africa. It is shown that relations between governments have directly effect on business activities. It should be kept in mind that African countries have their big influences on the market.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.20 no.4
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• pp.199-205
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• 2015

Nitrogen and phosphorus are the limiting elements for growth of phytoplankton, which is a major primary producer of marine ecosystem. Incidentally the stoichiometry of N/P of ocean waters, measured by the (nitrate + nitrite)/phosphate ratio converges to a constant of 16. This characteristic ratio has been used widely for the understanding the ecosystem dynamics and biogeochemical cycles in the ocean. In the East Sea, several key papers were issued in recent years regarding the climate change and its impact on ecosystem dynamic and biogeochemical cycles using N/P ratio because the East Sea is a "miniature ocean" having her own meridional overturning circulation with the appropriate responding time and excellent accessibility. However, cited N/P values are different by authors that we tried to propose a single representative value by reanalyzing the historical nutrient data. We present N/P of the East Sea as $12.7{\pm}0.1$ for the year 2000. The ratio reveals a remarkable consistency for waters exceeding 300m depth (below the seasonal thermocline). We recommend to use this value in the future studies and hope to minimize confusion for understanding ecosystem response and biogeochemical cycles in relation to future climate change until new N/P value is established from future studies.

• Korean Journal of Environment and Ecology
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• v.28 no.2
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• pp.105-112
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• 2014

During incubation, pelagic seabirds undergo large variations in their body mass as a result of concomitant fasting. In Procellariifomes undergoing important changes in body mass through the incubation, body mass regulation could be an important factor in behavioural decisions for changing activities during the incubation. The aim of this study was to investigate the effect of individuals' quality and incubation behaviour on their body mass regulation in Streaked Shearwaters Calonectris leucomelas breeding at Sasudo Island, in Jeju, South Korea during incubation period, June to August in 2013. In our results, we found that there was no relationship between the daily body mass loss and body size or condition of Streaked Shearwaters. However, the daily body mass loss increased significantly as the incubation bout increased. Moreover, the daily incubation bout was positively related to their body size. Consequently, although breeders' qualities were not related to their daily body mass loss during the incubation, the incubation behaviour affecting their daily body mass loss was regulated by their body size. Therefore, the body size of Streaked Shearwater breeders is one of important factors in their decisions for the incubation behaviour.

• Journal of the Korea Society of Computer and Information
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• v.13 no.4
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• pp.231-240
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• 2008

In respect complication, group and period, the foreign direct investment of korea is composed of various factors. This paper studies focus on estimating the determinants of foreign direct investment of korea. The region of analysis consist of 7 groups, that is, Asia, Europe, Central and South America, Oceania, Africa, Middle East. Analyzing period be formed over a 67 point(2002. 6${\sim}$2007. 12). In this paper dependent variable setting up an amount of foreign direct investment, explanatory(independent) variables composed of gross domestic product, a balance of current accounts, the foreign exchange rate, employment to population ratio, an average of the rate of operation(the manufacturing industry), consumer price index, the amount of export, wages(a service industry). For an actual proof analysis, LIMDEP 8.0 software, analysis model is random effect in TWECR The result of estimating the determinants of foreign direct investment of korea provides empirical evidences of significance positive relationships between employment to population ratio and wages(a service industry). However this study provides empirical evidences of significance negative relationships between the foreign exchange rate, censurer price index and the amount of export. The explanatory variables, that is, an average of the rate of operation(the manufacturing industry), gross domestic product and a balance of current accounts, are non-significance variables.

• Ocean and Polar Research
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• v.40 no.4
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• pp.213-222
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• 2018

We investigated seasonal variations in the abundance of the adults and the resting eggs of copepods to understand the role of copepod resting eggs for maintaining their population inhabiting the coastal area of Dadaepo, Korea. Adults and resting eggs of copepods were collected bi-monthly with a conical net (45 cm mouth diameter, $330{\mu}m$ mesh size) and van Veen grab ($0.1m^2$ area), respectively, from October 2016 to September 2017. The species of resting eggs were identified using mtCOI gene. The mean abundance of copepods was highest in October ($3686{\pm}1190inds{\cdot}m^{-3}$) and lowest in January ($176{\pm}60inds{\cdot}m^{-3}$) with the dominance of Paracalanus parvus s.l.. Among copepod producing resting eggs, Acartia omorii and Centropages abdominalis were dominant. The mean abundance of resting eggs was the highest in July ($9148{\pm}6787eggs{\cdot}m^{-2}$) and the lowest in October ($530{\pm}348eggs{\cdot}m^{-2}$). Most of the collected resting eggs were identified as A. omorii's. The mean abundances of A. omorii adults and resting eggs were highest in July, and both abundances fluctuated in a similar pattern except in September. In September, A. omorii adults were observed in a state of low abundance, while their resting eggs occurred in a state of high abundance. These results suggest that A. omorii maintain their population by producing a large quantity of resting eggs, particularly diapause eggs, before the seawater temperature rises. These eggs would hatch and be newly recruited to their population when the environmental condition becomes favorable.

• Journal of the Korean Society for Library and Information Science
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• v.19
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• pp.3-22
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• 1990

이 글은 1990년 10월 29일부터 11월 1일까지 서울 아카데미 하우스에서 열린 제11차 국제문헌정보연맹 아시아$\cdot$태평양위원회 학술회의에서 행한 기조연설의 내용이다. 이 학술회의의 주제인 국가정보정책의 현황과 주요 문제를 정리하여 제시하는 것이 기조연설자가 맡은 과제라 보고 첫째, 최근 수년간 한국정부가 입안 실행한 산업정보정책을 살펴보고 둘째, 일반적으로 개발도상국에서 국가산업정보정책은 누가 입안하고, 입안된 정책은 누가 실행하며, 한국의 경우는 어떤지를 살펴보았다. 산업정보정책은 한 나라의 산업정보봉사활동이 이루고자하는 여러 목표들을 열거한 것이며, 다른 분야의 경우와 마찬가지로 정부에 의하여 결정된다. 산업정보정책을 심의 결정하여 공포하는 것도, 지정된 기관에 재정지원을 제공하거나 법적 의무를 지워 공포된 정책을 실행하는 것도 정부의 책임이다. 제6차 경제사회발전 5개년 계획(1987-91) 속에 표시된 한국정부의 전반적 산업정보정책은 $\ulcorner$산업기술정보 유통지원을 강화하여 현행 산업연구원내 기술정보유통센터의 운영을 대폭 강화하고 전국적 온라인 전산망을 구축하여 산업연구원을 명실 상부한 국가의 중추적 기술정보유통기관으로 육성해나가는 한편 이를 토대로 기술정보 거래시장(테크노 마켓트)을 설치 운영$\lrcorner$하는 것이다. 산업정보정책은 산업발달을 위한 정책 속에 통합되고, 그것은 다시 경제발전 및 기타 부문의 국가발전 정책 속에 포함되는 것이 바람직하다. 한국에서 일반경제정책은 경제기획원이, 산업정책은 상공부 가, 기술정책은 과학기술처가, 재정정책은 재무부와 한국은행이, 통신정책은 체신부가 심의 입안한다. 산업정보정책의 일부를 이루는 산업정책 입안의 주요 책임은 상공부의 산업정책국에 있다. 모든 개발도상국에 꼭 같이 적용할 수 있는 국가산업정보정책 입안 및 실행 지침 같은 것을 마련하기는 어렵다. 그것은 이 분야에 개발된 일반모형이 없고 또 개발도상국이라고 하는 것이 동질집단이 아니기 때문이다. 개발도상국 사이에는 그 경제 발전면에서 뿐만 아니라 정보활동 면에서도 큰 수준 차가 있다. 각 개발도상국은 그 나라 고유의 전통과 형편에 맞는 산업정보정책을 마련하여야 한다. 그렇지만 발전 수준이 비슷한 다른 나라의 산업정보정책을 검토하여 자국의 가능성과 제한점을 바르게 이해하는 일은 적절한 정책 입안에 있어서 도움이 될 것이다. 본 기조연설은 아시아와 대양주의 다른 개발도상국 정책 입안자들에게 그러한 검토자료를 제공할 목적으로 행해진 것이다.

• Geophysics and Geophysical Exploration
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• v.11 no.1
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• pp.1-14
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• 2008

We present a method for interpreting seismic records with arrivals and waveforms having characteristics which could be generated by extremely inhomogeneous velocity structures, such as non-typical oceanic crust, decollement at subduction zones, and seamounts in oceanic regions, by comparing them with synthetic waveforms. Recent extensive refraction and wide-angle reflection surveys in oceanic regions have provided us with a huge number of high-resolution and high-quality seismic records containing characteristic arrivals and waveforms, besides first arrivals and major reflected phases such as PmP. Some characteristic waveforms, with significant later reflected phases or anomalous amplitude decay with offset distance, are difficult to interpret using only a conventional interpretation method such as the traveltime tomographic inversion method. We find the best process for investigating such characteristic phases is to use an interactive interpretation method to compare observed data with synthetic waveforms, and calculate raypaths and traveltimes. This approach enables us to construct a reasonable structural model that includes all of the major characteristics of the observed waveforms. We present results here with some actual observed examples that might be of great help in the interpretation of such problematic phases. Our approach to the analysis of waveform characteristics is endorsed as an innovative method for constructing high-resolution and high-quality crustal structure models, not only in oceanic regions, but also in the continental regions.