• Korean Journal of Remote Sensing
• /
• v.34 no.2_2
• /
• pp.431-437
• /
• 2018

We analyzed the feasibility of detecting wave gliders moving on the sea surface using SAR images. For the experiment, a model was constructed and placed on the sea using a towing ship before and after the satellite observation time. In the acquisition of KOMPSAT-5 image, high resolution SAR data of spotlight mode was collected considering the small size of wave glider. As a result of the backscattering intensity analysis around the towing ship along with wave glider, several scattering points away from the ship were observed, which are not strong but clearly distinguished from the surrounding clutter values. Considering the distance from the center of the ship, it seems to be a signal by the wave glider. On the other hand, it is confirmed that the wave glider can be detected even at the very low false alarm rate ($10^{-6}$) of the target detection using CFAR. Although the scatter signal by the wave glider could be distinguished from the surrounding ocean clutter in the high resolution SAR image, further research is needed to determine if actual wave gliders are detected in various marine environments.

• Journal of Korea Port Economic Association
• /
• v.25 no.2
• /
• pp.57-72
• /
• 2009

The purpose of this paper is to show the empirical measurement way of operation risk evaluation in domestic seaports for overcoming the limitations which the traditional DEA method has by using 13 Korean ports in 2003 for 4 inputs(birthing capacity, cargo handling capacity, number of coastal guard vessel, number o f coastal special guard vessel ) and 5 outputs(Export and Import Quantity, Number of Ship Calls, number of coastal accident, number of coastal crime, number of coastal pollution). Because traditional DEA method has produced the limited set of information, negative DEA mixed with tier, stratification and layering methods should be adopted. The goal of negative DEA is to set up DEA models that will place the poor operating ports on or close to the empirical frontier. The core empirical results of this paper are as follows. First, Donghae ports should benchmark the operation way of Yeasu, Busan, Woolsan ports in terms of the middle and longterm base. Second, 5 ports(ports of Taean, Yeasu, Tongyoung, Busan, Sokcho) which were revealed as the poor operating ports in Negative DEA analysis should benchmark Incheon, Woolsan, Pohan, and Donhae ports. The policy implication to the Korean seaports and planners is that Korean seaports should introduce the new methods like Negative DEA of this paper for predicting the poor operating in the ports.

• Journal of Navigation and Port Research
• /
• v.45 no.6
• /
• pp.346-351
• /
• 2021

With the goal of eradicating overwork, overload, and speeding of general freight cars(cargo) by the Ministry of Land, Infrastructure and Transport, Infrastructure and Transport, the "The Fare of safe transportation for freight cars System" has been enforced since 2020. 'The Fare of safe transportation for freight cars' rate for each item is being applied and supplemented, but the 'The Cost of safe transportation for freight cars' of general freight cars (cargo) and steel items is under discussion. The purpose of this study was to estimate the willingness to pay( WTP) for cargo. A survey was conducted on shippers, transportation companies (arrangers, carriers), and cargo drivers (using direct questioning among contingent valuation method (CVM) and the Tobit Regression analysis was conducted, and the average and median values of freight rates were derived using the estimated results, and the willingness to pay by tonnage of freight cars was confirmed. It is expected that the results of this study can be used as a reference to the "The Fare of safe transportation for freight cars Committee" an organization for deliberation and resolution of the 'The Cost of safe transportation for freight cars'.

• Journal of Navigation and Port Research
• /
• v.44 no.6
• /
• pp.509-516
• /
• 2020

Korea has gradually been developing port distriparks in major domestic trade ports to diversify their function and create added-value. New tenant companies are needed to help achieve these goals, but no research has been done on selection criteria. To provide such criteria, this study conducted a comparative analysis of the productivity of tenant companies in Busan New Port Distripark based on their characteristics. SFP (single-factor productivity) was measured using the operational data of 67 companies in the distripark over the past - three years (2017-2019). The results indicate that the logistics business and the manufacturing business have strengths in cargo volume productivity and in sales productivity respectively. Also, Northern distripark, a relatively older facility, was found to be more productive than Ung-dong distripark. Finally, the effect of investment-both foreign and in FAC/EQ (facility and equipment)-on productivity showed an inverse relationship with productivity, with the companies with under-average investments being more productive than those whose investments were above average. Therefore, to enhance the productivity and competitiveness of port distriparks, tenant companies must be subject to supplemented system and law for increasing employment and cargo volume, and reestablished selection criteria.

• Journal of the Korean Geophysical Society
• /
• v.5 no.4
• /
• pp.293-303
• /
• 2002

Applying elastic plate model, we estimated elastic thickness and rigidity of the lithosphere in southern part of the Korean Peninsula($332km{\times}332km$ area of which center is $36.5^{\circ}N$ in latitude and $127.5^{\circ}E$ in longitude) by analysing terrain data and gravity data measured up to 2002. We tried to exclude the East Sea in choosing the study area because it has different tectonic environment. The mean Moho depth was estimated to be 30 km by power spectrum analysis of gravity data in the study area, Assuming one layer crust and applying elastic plate model, the loads with wavelengths of greater than 300 km are locally compensated, loads with wavelengths in the range 80-300km are partially supported by the strength of the lithosphere, and loads with wavelengths of less than 80km are almost completely supported by lithospheric strength. Assuming crustal model and rigidity, we calculated predicted coherence and compared it with observed coherence. As a result, we wert able to estimate the effective elastic thickness to be of 15 km(corresponding flexural rigidity is $3.0{\times}10^{22}Nm$). This indicates that the crust of the study area is relatively weaker than other old and stable continental regions but is similar to continental margins or oceanic area. The low rigidity could be explained by many tectonic and thermal activities such as orogenic activities, magmatic intrusions, volcanic activities, foldings, faultings, etc.

• Journal of the Korean Association of Geographic Information Studies
• /
• v.20 no.1
• /
• pp.85-97
• /
• 2017

In recent years, the damage scales of water disasters such as typhoons, tsunamis, and heavy snow have been increasing globally as a result of global warming and climate changes. In particular, the economic loss caused by typhoons has been increasing for overpopulated areas that have undergone economic development and urbanization since the 1960s. In this study, we investigated and analyzed satellite images captured before and after typhoons on the Korean peninsula, including Typhoon Chaba (2016), Typhoon Rusa ('02), and Typhoon Maemi ('03). There was a limitation in utilizing existing satellites. Domestic satellites have mostly been developed and operated for the observation of the weather, ocean, and topography, as well as for use in communication. There are therefore insufficient temporal and spatial observations for water management and disaster response. In this work, we expanded the scope to overseas satellites and collected data from GMS, TRMM, COMS, and GPM. In the future, it will be necessary to develop and launch water resources satellites that can provide sufficient temporal and spatial data analysis units to obtain rapid and accurate water hazard information for the Korean peninsula.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.17 no.4
• /
• pp.464-473
• /
• 2016

The air temperatures of the coast and inland are rising due to an increase in carbon dioxide emissions and abnormal climate phenomena caused by global warming, El Nino, La Nina and so on. The sea levels of the Earth are rising by approximately 2.0 mm per year (global average value) due to the thermal expansion of sea water, melting of glaciers and other causes by global warming. On the other hand, when it comes to designing a hydraulic structure or coastal hydraulic structure, the standard of the design water level is decided by analyzing four largeness tide values and a harmonic constant with the observed tidal water level or simulating numerical model. Therefore, the design tidal water level needs to consider an increasing speed of the seawater level, which corresponds to the design frequency. In the present study, the observed tidal water levels targeting 46 tidal stations operated by the Korea Hydrographic and Oceanographic Administration (KHOA) from the beginning of observations to 2015 per hour were collected. The variation of the monthly and yearly and increasing ratio were performed and divided into 7 seas, such as east and west part of the Southern Sea, south part and middle of the East Sea, south part and middle of the Western Sea, and Jeju Sea. The current study could be used to determine the cause of local seawater rises and reflect the design tidal water level as basic data.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.31 no.2
• /
• pp.142-152
• /
• 1995

The combined bottom trawl and hydroacoustic survey was conducted by using the training ship Oshoro Maru belong to Hokkaido University in November 1989-1992 and the training ship Nagasaki Maru belong to Nagasaki University in April 1994 in the East China Sea, respectively. The aim of the investigations was to collect the target strength data of fish school in relation to the biomass estimation of fish in the survey area. The hydroacoustic survey was performed by using the scientific echo sounder system operating at three frequencies of 25, 50 and 100kHz with a microcomputer-based echo integrator. Fish samples were collected by bottom trawling and during the trawl surveys, the openings of otter board and net mouth were measured. The target strength of fish school was estimated from the relationship between the volume back scattering strength for the depth strata of bottom trawling and the weight per unit volume of trawl catches. A portion of the trawl catches preserved in frozon condition on board, the target strength measurements for the defrosted samples of ten species were conducted in the laboratory tank, and the relationship between target strength and fish weight was examined. In order to investigate the effect of swimbladder on target strength, the volume of the swimbladder of white croaker, Argyrosomus argentatus, sampled by bottom trawling was measured by directly removing the gas in the swimbladder with a syringe on board. The results obtained can be summarized as follows: 1.The relationship between the mean volume back scattering strength (, dB) for the depth strata of trawl hauls and the weight(C, $kg/\textrm{m}^3$) per unit volume of trawl catches were expressed by the following equations : 25kHz : = - 29.8+10Log(C) 50kHz : = - 32.4+10Log(C) 100kHz : = - 31.7+10Log(C) The mean target strength estimates for three frequencies of 25, 50 and 100 kHz derived from these equations were -29.8dB/kg, -32.4dB/kg and -31.7dB/kg, respectively. 2. The relationship between target strength and body weight for the fish samples of ten species collected by trawl surveys were expressed by the following equations : 25kHz : TS = - 34.0+10Log($W^{\frac{2}{3}}$) 100kHz : TS = - 37.8+10Log($W^{\frac{2}{3}}$) The mean target strength estimates for two frequencies of 25 and 100 kHz derived from these equations were -34.0dB/kg, -37.8dB/kg, respectively. 3. The representative target strength values for demersal fish populations of the East China Sea at two frequencies of 25 and 100 kHz were estimated to be -31.4dB/kg, -33.8dB/kg, respectively. 4. The ratio of the equivalent radius of swimbladder to body length of white croaker was 0.089 and the volume of swimbladder was estimated to be approximately 10% of total body volume.

• Journal of Navigation and Port Research
• /
• v.37 no.1
• /
• pp.29-34
• /
• 2013

In this study, the corelation among the knowledge of and attitude to health care and the actual health protective practices of seafarers was surveyed and analyzed in order to provide the management method for improving seafarers' health care. The subjects of this study were 516 seafarers who took refresh training courses in Korea Institute of Maritime and Fisheries Technology. The questionnaire was constructed under the Guidelines for National Health of the Ministry of Health and Welfare and modified for studying seafarers' health state. The collected data were analyzed by SPSS package. The results were as follows: 1) The older, married, religion believer, higher ranker, the man who have longer career have the higher degree of knowledge, attitude, and practice-degree(p<0.05). 2) The degree of knowledge, attitude, and practice are $4.24{\pm}0.35$, $3.45{\pm}0.41$, and $3.39{\pm}0.22$ in mean by 5-score scale, respectably. 3) The corelation among the degree of knowledge, attitude, and practice was significant(r=0.33~0.63, p<0.05).

• Korean Journal of Plant Resources
• /
• v.30 no.2
• /
• pp.176-190
• /
• 2017

South Korea is the northernmost distributional territory on the Camellietea japonicae (evergreen broad-leaved forests of the warm-temperate zone) in East Asia. A total of 40 stands were collected in terms of an ecologically-naturalized wild tea population (WTP), and their species composition was analyzed by $Z{\ddot{u}}rich$-Montpellier School's method with preliminary regard to forest canopy idendtification. Stand types were characterized by ecological flora's criteria such as Raunkiaer's life-form, neophyte, zonal distribution, and nativeness of species. Expansion of WTP distribution into the interior of the peninsula was recognized, than expected. The highest and northernmost WTPs have been recorded at Mt. Palgong, Daegu (390 m a.s.l.) and Iksan Jeonbuk (latitude $36^{\circ}$ 03' 33''), respectively. Altitudinal and latitudinal WTP distribution of Korea under continental climate shows lower than Japanese situation under oceanic climate. Community structure generally involved a few human interferences. Syngeographically WTP distribution was limited on the warm-temperate zone and the southernmost cool-temperate southern submontane zone. First driving force on distributional expansion of the WTP was anthropogenic, particularly in the northernmost distribution area. We finally confirmed an actual existence of the WTP in South Korea and suggested a long-term monitoring on the WTPs in national view of in-situ genetic resources with higher frost-resistance.