• Journal of the Korean Institute of Navigation
• /
• v.16 no.3
• /
• pp.43-53
• /
• 1992

1992년 전반기에 우리나라에 근해해운기업 3개사가 도산하였으며, 많은 그해해운기업이 심한 경영상의 어려움을 겪고 있다. 그러한 도산이유를 대별하면 기업 내적요인과 기업 외적요인으로 나눌 수 있을 것이다. 이 논문에서는 기업외적 요인의 하나로서 근해지역에 있어서의 선박의 과잉공급과 운임의 덤핑을 상정하고서 최근 소련의 연방해체 이후 극동지역에서 생성되기 시작한 러시아의 해운사기업의 생성배경 및 경영형태를 분석하고, 그러한 러시아의 해운사기업이 보유하고 있는 선박이 우리나라의 근해해운시장에 미치는 영향을 살펴본 뒤 이에 대처하기 위한 우리나라 해운정책의 기본방향을 제시한다. 이 논문의 목적을 달성하기 위하여 사용된 연구방법은 문헌조사, 현장조사, 그리고 면접법이다. 본 연구는 러시아 해운사기업의 생성근원이 되는 국영해운기업, 실제로 극동지역에서 경영되고 있는 러시아의 해운 기업 및 러시아 연방정부의 교통부산하 해운국을 방문하여 각 조직의 최고 책임자 및 주요 인사를 대상으로 면접과 현장조사를 실시하였으며, 일본 및 러시아의 해운연구기관의 주요인사와 우리 나라의 해운기업의 최고경영자들도 본 연구의 면접대상에 포함되었다. 이 연구에서 도출된 주요 결과로서는 첫째, 러시아의 해운사기업은 소련연방산하에 이었던 국영해운기업에서 제공된 매운 낮은 용선료의 선박과 우리나라의 근해선사 또는 대리점과의 노우 하우(know-how) 의 결합에 의해 생성되었으며 둘째, 그러한 매커니즘에 의해서 우리나라 근해지역에 영업활동중인 러시아 선박은 재화중량톤수 약 4천 내지 5천톤에 해당하는 하천.해상형태(river sea type)의 살물선으로서 총 40여척에 달하고 있으며, 셋째, 그러한선박의 용선료는 1992년 3월에 현재 우리나라 근해해운시장에서 형성된 용선료 수준의 50% - 60%에 해당하며, 넷째, 우리나라의 근해화물을 원활하게 확보.수송하기 위하여 일부의 선박은 편의치적국의 선적을 이용하여 운항되기도 한다. 이 연구의 결과를 바탕으로 한 정책적 제언은 경영기술, 자본력, 선박의 질적수준 및 경쟁의 측면에서 일본보다도 취약한 상태에 있는 우리나라의 근해해운을 성장.발전시키기 위해서는 정부는 먼저 연안해운에 적용시키고 잇는 면허제도를 점진적으로 개방화시켜 우리나라의 연안해운의 자본력을 증강시키고 경쟁원리에 의한 경쟁력을 제고시켜야 하며, 제 2선적제도의 발달과 해운경영의 국제성에 맞추어 근해해역에서 활동하는 우리나라의 선박에대해서 부분적으로 선박의 국적을 점차 개방시켜 나가는 정책을 검토해야 할 단계라는 것이다. 이러한 점에 있어서 지난 30여년간 외항해운부문에 중점을 두어온 우리나라의 해운정책은 이제 근해해운정책의 개발에도 관심을 기울여야 하는 전환점에 있다고 할 수있다.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.18 no.5
• /
• pp.1-9
• /
• 2017

Recently, the active research into wireless sensor networks has led to the development of sensor nodes with improved performance, including their mobility and location awareness. One of the most important goals of such sensor networks is to transmit the data generated by mobile sensors nodes. Since these sensor nodes move in the mobile wireless sensor networks (MWSNs), the energy consumption required for them to transmit the sensed data to the fixed sink is increased. In order to solve this problem, the use of mobile sinks to collect the data while moving inside the network is studied herein. The important issues are the mobility and energy consumption in MWSNs. Because of the sensor nodes' limited energy, their energy consumption for data transmission affects the lifetime of the network. In this paper, a mobile-sink based energy-efficient clustering scheme is proposed for use in mobile wireless sensor networks (MECMs). The proposed scheme improves the energy efficiency when selecting a new cluster head according to the mobility of the mobile sensor nodes. In order to take into consideration the mobility problem, this method divides the entire network into several cluster groups based on mobile sinks, thereby decreasing the overall energy consumption. Through both analysis and simulation, it was shown that the proposed MECM is better than previous clustering methods in mobile sensor networks from the viewpoint of the network energy efficiency.

• Proceedings of the KSRS Conference
• /
• v.1
• /
• pp.34-37
• /
• 2006

When tsunami waves propagate across open ocean they are steered by Coriolis force and refraction due to gentle gradients in the bathymetry on scales longer than the wavelength. When the wave encounters steep gradients at the edges of continental shelves and at the coast, the wave becomes non-linear and conservation of momentum produces squirts of surface current at the head of submerged canyons and in coastal bays. HF coastal ocean radar is well-conditioned to observe the current bursts at the edge of the continental shelf and give a warning of 40 minutes to 2 hours when the shelf is 50-200km wide. The period of tsunami waves is invariant over changes in bathymetry and is in the range 2-30 minutes. Wavelengths for tsunamis (in 500-3000 m depth) are in the range 8.5 to over 200 km and on a shelf where the depth is about 50 m (as in the Great Barrier Reef) the wavelengths are in the range 2.5 - 30 km. It is shown that the phased array HF ocean surface radar being deployed in the Great Barrier Reef (GBR) and operating in a routine way for mapping surface currents, can resolve surface current squirts from tsunamis in the wave period range 20-30 minutes and in the wavelength range greater than about 6 km. There is a trade-off between resolution of surface current speed and time resolution. If the radar is actively managed with automatic intervention during a tsunami alert period (triggered from the global seismic network) then it is estimated that the time resolution of the GBR radar may be reduced to about 2 minutes, which corresponds to a capability to detect tsunamis at the shelf edge in the period range 5-30 minutes. It is estimated that the lower limit of squirt velocity detection at the shelf edge would correspond to a tsunami with water elevation of less than 5 cm in the open ocean. This means that the GBR HF radar is well-conditioned for use as a monitor of small and medium scale tsunamis, and has the potential to contribute to the understanding of tsunami genesis research.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.34 no.4
• /
• pp.1181-1190
• /
• 2014

In this study, the erosional parameters for deposit beds were quantitatively estimated domestically for the first time through the erosion tests using an annular flume. Four erosion tests were carried out for the deposit beds with different consolidation structures, which were obtained by consolidating the kaolinite slurries for a given time durations. Results of erosion tests showed that the bed shear strength ${\tau}_s$ increased with the consolidation time and bed depth. The erosion rate ${\epsilon}$ was also shown to be related well with the excess shear stress ${\tau}_b-{\tau}_s$ which was given by the difference between flow shear stress ${\tau}_b$ and bed shear strength ${\tau}_s$. While the logarithm of the erosion rate was linearly related with the excess shear stress as ${\tau}_b-{\tau}_s{\geq}0.1N/m^2$, however, the erosion rate decreased rapidly with it when ${\tau}_b-{\tau}_s{\leq}0.1N/m^2$. These erosion test results were also shown to be good enough to verify by comparing with the test results from previous studies and a new equation was suggested to describe the erosion rate more well in the region of ${\tau}_b-{\tau}_s{\leq}0.1N/m^2$.

• Journal of the Korean Association of Geographic Information Studies
• /
• v.10 no.1
• /
• pp.136-145
• /
• 2007

Redevelopment about land that nature green tract of land and dilapidated city equipment including greenbelt make a strong resolution in city with change of town planning area according to growth of city is consisting. Formation of city of these phenomenon is old and personality of city changes rapidly, the speed becomes fast. Phenomenon that Busan moves to neighborhood area as convenience of traffic of industrial facilities that was on spearhead of economic growth move to outer wall of city and port facilities is deterioration, as becoming decline Tuesday industry form of city in the second industry the third phenomenon that alter by the 4th happen and case of residential area old residential area of inland area change for the worse of habit be and impulse to steal is augmented in the 1970, 80 is appearing. Hereupon the result inland area which analyzes the change with the use area compared to the area where it is coming in contact to the coast the diffusion of the residential area or the business park appears area, the factory back of nine cities acts Gangseo-gu or Gijang-gun of the industry area this with the fact that it changes.

• Clean Technology
• /
• v.23 no.1
• /
• pp.54-63
• /
• 2017

Volatile organic compounds (VOCs) are widely used in both industrial and domestic activities. VOCs are one of the most unpleasant, frequently complaint-rousing factors of pollution around the world. It is now necessary to research and develop an alternative technology that could overcome the problems of the existing odor-control and VOC-eliminating techniques. In this study, essential oil and photocatalytic process was applied in the removal of benzene and toluene, typical VOCs in petrochemistry plant. therefore, this study conducted experiments on the selection of appropriate essential oil, photodegradation, hydroxyl radical generation capacity. The removal efficiency and reaction rate were performed to selecte the type and concentration of essential oil. As a result, removal efficiency of Hinoki Cypress oil was approximately 70% and reaction rate of Hinoki Cypress was high. The results of photolysis experiment, photocatalytic oxidation process showed that the decomposition efficiency of VOCs increased considerably with increasing UV lamp power. In addition, the conversion of VOCs was increased up to $0.1gL^{-1}$ photocatalysts. The hydroxyl radicals measure was performed to determine the ability to generate hydroxyl radicals. The analytical result showed that high $TiO_2$ concentration and lamp power was produced many hydroxyl radical. Experiments of the removal efficiency and reaction rate were performed using essential oil and photooxidation. As a result, the removal efficiency showed that the removal efficiency was increased high temperature and reaction time. The activation energy was calculated from the reaction rate equation at various temperature condition. Activation energy was approximately $18kJmol^{-1}$.

• Journal of the Korean Institute of Navigation
• /
• v.25 no.4
• /
• pp.347-360
• /
• 2001

The purpose of this study is to find out the subjective and objective fatigue level and the characteristics of seamen's physical strength with the service period on board, to have a new understanding of the vocation, and to explore a physical exercising program for the seamen. The questionnaire survey for the seamen who had been in service on the ocean going vessels was conducted and the results are fumed out as the followings. Total number of seamen who had answered the questionnaire was 64 persons and the distribution status of service period group was identified as 16 persons for each of 4 groups； the group was classified as the group of less than 5 years, 5 - 10 years, 10 - 15 years, and more than 15 years. 1. Working conditions Working hours in a week was identified as 44－56 hours(45.3%) and the number of 45.3% of the seamen answered the working hours in week is more than 56 hours. The seamen of 25.0% are unsatisfied or very unsatisfied with their vocation. The seamen of 65.6% are smoking, and 45.3% of them drink. The seamen of 44.,3% drink once or more in a week. And the seamen of 67.2% do not take any exercise in a week. 2. Contribution to the seamen's fatigue and subjective symptom The most contributive factor to the seamen's fatigue was identified as the short of sleeping(21.5%), overwork(19.2%), poor working conditions (18.6%), and the friction in human relations also becomes one the contribution to the fatigue(14.0%). The subjective symptom by fatigue was identified as the feeling of languid, sleepy and tiredness of eyes. 3. Characteristics of the seamen's physical strength and Interrelations The grip strength and back strength of the seamen whose service period is less than 5 years were measured as 40.44kg and 127.8kg. The sit ups in the group of service period less than 5 years was measured as 36.84 times, and the vertical jump for the seamen in this group was measured as 46.55cm. The closed-eyes foot balance was measured as 33.64 seconds in the group of service period between 5 and 10 years, and side-step was measured as 35.31 times in the group of service period less than 5 years. The standing trunk flexion was measured as 10.54cm for the seamen whose service period is between 10-15 years, and the trunk extension was measured as 50.70cm for the seamen whose service period is less than 5 years. And the step test of the seamen whose service period is between 10-15 years was measured as 54.44 numbers, and the number of flickers of the seamen whose service period is less than 5 years was measured as 32.94.

• Journal of the Korean Geotechnical Society
• /
• v.18 no.2
• /
• pp.147-160
• /
• 2002

According to the Korean Design Code for port and harbor facilities, bearing capacity of rubble mound under eccentric and inclined load is calculated by the simplified Bishop method, and strength parameters are recommended to be c=0.2kg/$cm^2$ and \phi=35^P\circ}$ fur standard rubble if the compressive strength of parent rock is greater than 300kg/$cm^2$, according to research results by Junichi Mizukami(1991). But this facts have never been verified in Korea because there was no large-scale triaxial test apparatus until 2000 in Korea. For the first time in Korea, the large-scale triaxial test(sample diameter 30cm ; height 60cm) on the rubble originated from porous basalt rock in North-Cheju was accomplished. Then strength parameters for basalt rubble produced in North-Cheju are recommended to be c:0.3kg/$cm^2\; and \phi=36^{\circ}$ if the compressive strength of parent rock is greater than 400kg/$cm^2$. And the shear behavior characteristics of rubble, represented as particle breakage and dilatancy, are investigated.

• Journal of Animal Environmental Science
• /
• v.8 no.3
• /
• pp.199-208
• /
• 2002

This paper introduces the method to make management network about milking cow farm tasks. The object of this research was to design of biological measuring system and managing network system in a livestock farm. This auto-management system provides informations about individual cows' temperature, conductivity of milk and weight for efficient management of feeding, and milking works by a micro-processor and RS -485 type serial COM. ports. And measured bio-data which are basic informations for remote raising management are saved to user PC by serial communication between the PLC and user PC. Milking cow farm is divided into three working place to each measurement work and feed. The first working place is milking station which has two thermometers, a conduct meter and a scale set. The second working place is feeding station, and the third place is cattle cage. These are combined by network system and the PLC which is used to drive network and sub-modules. Sub-modules have a micro-process to control the sensor and to interface with network. The PLC which drive network and control sequence has two serial communication port to be linked with user PC for sending the measured data and for receiving data. Above all, in this study tells the sequence operating method by the driving scenario of breeding milk cow for livestock auto-management using the PLC and network system.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.45 no.10
• /
• pp.31-38
• /
• 2008

This paper describes sensor network system implementation for the IEEE 1451.2 standard which guarantees compatibilities between various wired sensors. The proposed system consists of the Network Capable Application Processor(NCAP) in the IEEE 1451.0, the Transducer Independent Interface(TII) in the IEEE 1451.2, the Transducer Electronic Data Sheet(TEDS) and sensors. The research goal of this study is to minimize and optimize system complexity for IC design. The NCAP is implemented using C language in personal computer environment. TII is used in the parallel port between PC and an FPGA application board. Transducer is implemented using Verilog on the FPGA application board. We verified the proposed system architecture based on the standards.