• The Transactions of the Korea Information Processing Society
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• v.3 no.1
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• pp.127-143
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• 1996

Advanced countries are very active in deploying the National Information I infrastructure which provides universal service to promise fruitful quality of futuree life. Even in the distributed environment, we can closely converse, work together, and share information in a very convenient way. This is actually enabled with the help of groupware technology, which are currently focused and researched in a larger popularity. The aim of this study is to design a portable pack for group communications management to support the development of groupware application. In the paper we begin with technical survey, continue to build our own model for group communications man agement, and design its architecture and procedure. We also suggest group addressing mechanism under Internet environment such as how to create IP multicast address and IP port number dynamically and as a globally unique value for the communication session, with the help of the hierarchical and distributed address managers. We also indicate the reliable data transmission services to remedy the unreliable feature of the UDP multicast services, and finally the architecture/ applied to support the practical applications is briefly discussed for verification of the designed concept.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.3
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• pp.541-547
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• 2017

In Yongwon channel, its natural flow of seawater is blocked by the construction of Busan Newport including the container berth. The channel was transformed into a narrow and long one, where it is possible that ships are only allowed to pass through the north-side channel of Gyeonmado located at the point of river mouth to Songjeongcheon. So it is considered that the changes in the terrain characteristics of Yongwon channel is likely to alter the circulation of sea water, thereby changing its water quality. Contaminants are accumulated from the sediment release. In this study, before and after dredging the sediment release test was performed. As a result, after the sediment dredging is performed, the reduction rate was higher at the same point. The results show that the water quality can be improved by dredging. Each group (A~C) reduction rate of the evaluation of the reduction rate of 4.64% T-N, 18.00%, 18.59%, respectively. T-P rate of 24.75% reduction, 24.17%, 44.08%, respectively. COD reduction rate was 18.57%, 19.76%, 38.08%, respectively. These results can be used as basic data for controlling the contamination by dredging in Yongwon channel.

• Ecology and Resilient Infrastructure
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• v.2 no.4
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• pp.274-283
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• 2015

The reservoir shores seem to be vulnerable to biological invasion. The purpose of this research was to find out the floristic composition of alien plants and their relationship between environmental factors on reservoir shorelines in Korea. We investigated flora of alien plants and environmental factors of geomorphology, hydrology, water quality and soil on the shoreline of a total of 35 reservoirs with different water level managements. There were 56 species of alien plants, which was 15% of the total plant species identified in the study of reservoirs. A total of 57% of these alien species were the species which were introduced shortly after opening the port from 1876 to 1921 in Korea. More than 80% of the alien plants on the reservoir shores originated from America and Europe. The current distribution of Ambrosia trifida and Paspalum distichum were restricted in the central part and the southern region of the Korean Peninsula, respectively. The water level fluctuation, flood frequency at the median water level, water pollution index, coverage of rock exposure and mean degree of shoreline slope were determined as important environmental factors that have an effect on the characteristics of shoreline alien flora. Our results suggest that the reservoir shore was in danger of being invaded by alien plants due to the water level management and other human disturbances. For effective conservation of the reservoir ecosystem, periodic monitoring systems are required for the early detection of alien species on the reservoir shore.

• Journal of the Korean Society of Marine Environment & Safety
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• v.22 no.6
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• pp.654-659
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• 2016

Recently, the passenger ship 'Sewol' capsized with an abrupt inclination while she was making a small angle alteration. It is very important to fully understand the concepts, causes and relevant corrections for a ship's transverse inclination, which is classified into heel, list and loll. In this study, the concept, development and calculation of loll were well considered and the actual magnitude of the angle of loll was simulated in a box-shaped model-ship experiment. The experimental values and its development according to different values of negative stability were compared with calculated values. In the results, experimental values for the angle of loll coincided closely with calculated values and the model inclined symmetrically on both port and starboard sides indicating an outstanding feature of loll. This study is expected to expand the concept of loll and help in the analysis of capsize incidents with unknown causes. Further experimental research or case studies concerning the risk of inappropriate correction for loll arising from misunderstandings will be needed.

• Journal of the Korean Society of Marine Environment & Safety
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• v.22 no.6
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• pp.639-646
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• 2016

In order to establish an operational standard based on ship size, this study considered a specific safety management plan for Ulsan along with international standards, analyzed the results of mooring safety assessment at four vulnerable piers and suggests cargo stoppage and emergency unberthing standards as follows. In accordance with ship characteristics, ships of less than 10,000 tons are recommended to limit their activities for wind speeds of 18-21 m/s and wave heights of 1.0-1.5 m. Ships from 10,000-50,000 tons are recommended to observe wind speeds of 17-20 m/s and wave heights of 1.2-1.5 m, while, ships of 50,000-100,000 tons are recommended wind speeds of 15-19 m/s and wave heights of 1.5 m. Ships of more than 100,000 tons are recommended wind speeds of 14-18 m/s and wave heights of 1.5 m.

• Journal of the Korean Society of Marine Environment & Safety
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• v.26 no.6
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• pp.615-623
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• 2020

In order to prevent the dangers of major marine accidents, it is very important to be aware of in advance through marine incidents in the background of Heinrich's law, formulated by the safety pioneer who is credited with focusing on workplace safety with emphasis on the human element. At least 11 cases of collision accidents occurred in the Busan VTS area from January 1st to December 31st, 2019, and 24 cases of VTS marine incidents were reported during the same period. According to Heinrich's law, there could be many more potentially risky situations besides the 24 reported cases. In this study, the criteria for VTS marine incidents were established through advanced research and a survey of VTS operators, and analysis of 24 cases of VTS marine incidents in the Busan VTS area. Traffic surveys were conducted for three days to identify potentially hazardous situations. According to the survey, there were 216 cases of VTS marine incidents, and within a year, it is estimated there could be about 26,280 cases. Even if conditions such as "missing VHF communication feedback" which is an important cause of marine incidents, are not reflected, there are many potential risks in the VTS area. Thus, it is vital to strengthen the VTS marine incident reporting system.

• Journal of Distribution Science
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• v.11 no.6
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• pp.31-40
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• 2013

Purpose - The Northeast Asian Logistic Hub strategy was established to create a national competitive advantage in northeast Asia. Countries in this region are competing fiercely to become the central base distribution port as the volume of container shipping continues to increase due to the northeast Asian (especially Chinese) economic growth. The primary method by which shippers are improving their customer service and distribution is enhancing profits by minimizing call ports on the key route through strategic affiliations and the use of large vessels. Each nation is planning large-scale investments in the construction of sea ports that can accommodate large vessels. This paper proposes ways by which the logistical strategies of domestic corporations can keep pace with changes in government policy concerning the Northeast Asian Business Hub policy. It examines the logistics system in the Northeast Asian region, analyzes the government's Northeast Asian Business Hub policy, and suggests logistical strategies for domestic corporations through an analysis based on a questionnaire designed to grasp domestic firms' needs and goals. Research design, data and methodology - The purpose of this study is to determine how shipping companies establish partnerships with third-party logistics providers and draws out the implications of the results. The survey methods used were personal interviews and questionnaires distributed to a sample population through e-mail, fax, mail, and telephone. A total of 600 questionnaires were distributed, of which 165 were returned. Among these, ten were excluded due to insufficient content; ultimately, 155 were used for the sample. The statistical data collection process was analyzed through data coating and a statistical package program. Results - This study argues that greater flexibility in policies, administration, and systems will be needed to significantly improve established business practices. In this dissertation, we primarily identify that in order to become a center of northeast Asian logistics, Korea must adopt a new paradigm and abandon the existing systems that are based on the economic and social systems that have stemmed from bureaucracy, inflexibility, chauvinism, and equalitarianism. Flexible policies, administration, and systems will be necessary to improve business practices. Domestic corporations must establish a strategic logistics hub and related network while simultaneously pursuing value-added logistics businesses by increasing their manpower and building a logistics information system. This will strengthen their competitive edge and lead to system improvements. Conclusions - Domestic corporations must adopt a new paradigm and use more reasonable business laws, systems, and policies that are based on market-driven flexibility and transparency. Moreover, social norms and regulations should be established to help ensure political and social security. Korea must also develop a culture of tolerance for foreign companies. Finally, the paradigm defining the policy governing the development of the capital city and its satellite cities in this context must be changed.

• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.1
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• pp.36-42
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• 2018

This paper considers the Marine Traffic Risk Assessment for fixed and moving targets, which threaten officers during a voyage. The Collision Risk Assessment Formula was calculated based on a dynamic ship domain considering the length, speed and maneuvering capability of a vessel. In particular, the Navigation Risk Assessment Model that is used to quantitatively index the effect of a ship's size, speed, etc. has been reviewed and improved using a hybrid combination of a vessel's dynamic area and the Collision Risk Assessment Formula. Accordingly, a new type of Marine Traffic Risk Assessment Model has been suggested giving consideration to the Speed Length Ratio, which was not sufficiently reflected in the existing Risk Assessment Model. The larger the Speed Length Ratio (dimensionless speed), the higher the CJ value. That is, the CJ value is presented well by the Speed Length Ratio. When the Speed Length Ratio is large, states ranging from [Caution], [Warning], [Dangerous] or [Very Dangerous] are presented from a greater distance than when the Speed Length Ratio is small. The results of this study, can be used for route and port development, including dangerous route avoidance, optimum route planning, breakwater width, bridge span, etc. as well as the development of costal navigation safety charts. This research is also applicable for the selection of optimum ship routing and the prevention of collisions for smart ships such as autonomous vessels.

• Journal of Korean Ophthalmic Optics Society
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• v.6 no.2
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• pp.71-75
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• 2001

In this paper, a three-dimensional measuring system of thermoluminescence(TL) spectra based on temperature, wavelength and luminescence intensity was introduced. The system was composed of a spectrometer, temperature control unit for thermal stimulation, photon detector and personal computer for control the entire system. Temperature control was achieved by using feedback to ensure a linear-rise in the sample temperature. Digital multimeter(KEITHLEY 195A) measures the electromotive force of Copper-Constantan thermocouple and then transmits the data to the computer through GPIB card. The computer converts this signal to temperature using electromotive force-temperature table in program, and then control the power supply through the D/A converter. The spectrometer(SPEX 1681) is controlled by CD-2A, which is controlled by the computer through RS-232 communication port. For measuring the luminescence intensity during the heating run, the electrometer(KEITHLEY 617) measures the anode current of photomultiplier tube(HAMAMATSU R928) and transmits the data to computer through the A/D converter. And, we measured and analyzed thermoluminescence of $CaSO_4$ : Dy, P using the system. The measuring range of thermoluminescence spectra was 300K-575K and 300~800 nm, $CaSO_4$ : Dy. P was fabricated by the Yamashita's method in Korea Atomic Energy Research Institute(KAERI) for radiation dosimeter. Thermoluminesce spectra of the $CaSO_4$ : Dy, P consist of two main peak at temperature of $205^{\circ}C$, wavelength 476 nm and 572 nm and with minor ones at 658 nm and 749 nm.

• Journal of the Korean Institute of Navigation
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• v.17 no.4
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• pp.1-21
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• 1993

The purpose of this paper is to search for reasonable and fair principles applicable to the delimitation of the Exclusive Economic Zone(which is called the EEZ, hereinafter) around the Korean Peninsula th-rought the comprehensive study of maritime boundary, which is one of the most important issues in the law of the Sea. So far, the sea has been exploited for activities such as fishery, transport and military stratedy, and en-vironmental policy and so on. From this time on, however, it becomes important to us as the major trea-sure-house of various resources which will be developed and used for diversified purposes. For these rea-sons, nowadays, more and more countries of the world are competing to secure waters as much as possible within their jurisdiction. And the regime of the EEZ was created as a result of this international trend. At last, it has been institutionalized as the 200-mile EEZ of a legal notion in the Convention on the Law of the Sea, which was adopted at the Third United Nations Conference on the Law of the Sea, in Jamaica on December 10, 1982. In adapting to this EEZ institution, Korea is faced with several complicated problems as it is bounded on three sides by the sea and all of its neighboring countries such as the PRC, the DPRK, Japan, Russia etc are less than 400 miles away between opposite countries. Therefore, when trying to delimit the boun-dary for the EEZ, it appears necessary to analyze applicable principles and rules of international law for delimitation mainly through the Convention on the Law of the Sea, and studies the trends of actual State practices and recent international precedents. It is hoped that such knowledge will enable Korea to secure sufficient resources and other sovereign rights without conflicting with the neighboring countries concer-ned. For the achievement of the above mentioned object. I analyzed the necessities of the establishment of the EEZ in Korea, the difficulties and practices of Korea's neighbors, and the changes and forthcoming trends in Korea's relations with its neighbors concerned on the basis of the general explanation of the EEZ regime. In conclusion, it is my opinion that for the establishment of the EEZ delimitation which neighbors around the Korean Peninsula should be applied reasonable and equitable principles considering the rele-vant circumstances which characterize the area definitely as well as the UN Convention on the Law of the Sea, 1982.