• The Korean Journal of Malacology
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• v.24 no.2
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• pp.153-159
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• 2008

We investigated artificial mass seed production of a Chinese scallop, Patinopecten yessoensis, in 2004. The GSI(gonad somatic index) of the Chinese scallop, P yessoensis was 17.2 on mid-February, 20.2 on mid-March, while that of Korean scallop, P yessoensis was 6.9 on mid-February, 10.8 on mid-March. Matured 120 females and 350 males were selected for artificial mass production. They were exposed in air for 1 hr at over $20^{\circ}C$, and placed into a spawning tank(20 ton) containing sea water treated with UV radiation at $12^{\circ}C$. We gained a total of 228,000 thousand scallop embryos between March 10th and 15th, and reared larvae at the indoor tank during 25 days. When the mean shell length of larvae reached 250 ${\mu}m$ and they have eye-spots, the number of pre-settling larvae was 47,500 thousand. We gained 1,850 thousand attached scallop spats from two kinds of collectors. Attached spats were reared in indoor tank for different periods from 5 days to 60 days. They were divided into 5 groups according to the length of reared days. Each group of attached spats was moved to intermediate rearing sites at Yangyang fishing port in Gangreung-city for acclimation to ocean environments. The highest survival rate of attached spats was 13.0% shown at the group reared for 12 days, but the significant difference in their growth was not found between the groups. The shell length of artificial attached spats increased from 0.9 ${\mu}m$ on July 10th to 24.7 ${\mu}m$ on December 16th with the survival rate of 85.0% while that of natural attached spats increased from 0.6 ${\mu}m$ on July 10th to 23.9 ${\mu}m$ on December 16th with the survival rate of 85.7%.

• Journal of the Korean Institute of Gas
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• v.23 no.6
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• pp.90-96
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• 2019

Natural gas has been regarded as one of major alternative fuels, because of the increment of mining shale gas and supplying PNG(Pipeline Natural Gas) from Russia. Thus, it needs to broaden the usage of natural gas as the increasing its supplement. In this situation, application of natural gas on the transport area is a good suggestion to reduce exhaust emissions such as CO₂(carbon dioxides) and soot from vehicles. For this reason, natural gas can be applied to SI(spark ignition) engines due to its anti-knocking and low auto-ignitibility characteristics. Recently, since turbocharged SI engine has been widely used, it needs to apply natural gas on the turbocharged SI engine. However, there is a major challenge for using natural gas on turbocharged SI engine, because it is hard to make natural gas direct injection in the cylinder, while gasoline is possible. As a result, there is a loss of fresh air when natural gas is injected by MPI (multi-point injection) method under the same intake pressure with gasoline-fueled condition. It brings the power reduction. Therefore, in this research, intake pressure was increased by controling the turbocharger system under natural gas-fueled condition to improve power output. The goal of improved power is the same level with that of gasoline-fueled condition under the maximum torque condition of each engine speed. As a result, the maximum power levels, which are the same with those of gasoline-fueled conditions, with improved brake thermal efficiency could be achieved for each engine speed (from 2,000 to 6,000 rpm) by increasing intake pressure 5-27 % compared to those of gasoline-fueled conditions.

• Korean Journal of Environment and Ecology
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• v.24 no.2
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• pp.157-165
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• 2010

This study was carried out to suggest the basic data of planting method for construction of buffer green space based on the land use in case of reclaimed land by analyzing land structure, planting concept, and planting structure in buffer green space, Rokko Island, Kobe, Japan. Rokko Island(total area: 580ha) is divided into port and logistics industry area and urban area by constructing the box type large-scale buffer green space. The land structure of buffer green space were biased mounding type, parallel mounding type, and complex mounding type. The width of buffer green space was 50meters in case of northern area, from 28 to 32meters in case of eastern area, and 37.5meters in case of western area, and the slope of that was from 18 to 25 degrees and the height of that was from 2 to 15meters. There were applied landscape and buffer planting concept on the sea side area of northern buffer green space, on the other hand landscape and shade planting concept on the Inner city side area of that. According to the result of planting structure analysis of northern buffer green space, the main woody species were those of deciduous-evergreen species grow in warm-temperate forest zone such as Quercus glauca, Cinnamomum camphora, Machilus thunbergii, Elaeagnus maritima. The results of maximum number of species and planting density by $100mm^2$ was that 9 species 22 individuals in canopy layer, 9 species 15 individuals in understory layer, 3 species 67 individuals in shrub layer, and 14 species 104 individuals in total. The plant coverage of northern buffer green space based on the ecological planting method was from 69 to 139% in case of canopy layer, from 26 to 38% in case of understory layer, from 6 to 7% in case of shrub layer, and from 101 to 184% in total. Index of plant crown volume of northern buffer green space based on the ecological planting method was from 1.40 to $3.12m^3/m^2$ in case of canopy layer, from 0.43 to $0.55m^3/m^2$ in case of understory layer, $0.06m^3/m^2$ in case of shrub layer, and from 1.89 to $3.73m^3/m^2$ in total.

• Journal of the Korean Society of Marine Environment & Safety
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• v.26 no.2
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• pp.175-185
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• 2020

Quantitative and qualitative surveys were conducted during scuba diving activity between May 2017 and June 2017 in order to analyze spring marine algal community structure at Gijang-gun, Busan. A total of 121 species including 13 (10.7 %) Chlorophyta, 18 (14.9 %) Phaeophyta, and 90 (74.4 %) Rhodophyta were identified. The species count in the subtidal zone (110 species) was twice as high as in the intertidal zone (56 species). In terms of regions, 88,76, and 75 species were found in Mundong, Gongsu, and Daebyeon, respectively. Mean biomass for the whole study area was 1,501.5 g·m^-2, higher for the subtidal zone (1,869.4 g·m^-2) than for the intertidal zone (1,133.5 g·m^-2). Mean biomass by region values were 2,234.0 g·m^-2, 1,228.1 g·m^-2, and 1,044.4 g·m^-2 for Mundong, Gongsu, and Daebyeon, respectively. Ulva australis, Sargassum thunbergii, and Corallina pilulifera had high biomass in the intertidal zone, while Sargassum macrocarpum, Undaria pinnatifida, and Phycodrys fimbriata had high biomass in the subtidal zone. The composition ratio of marine algal functional forms suggests that the entire study area had 'Low' status, and all sites fell within 'Low' to 'Moderate' status. Results indicate that opportunistic species are widely distributed throughout the Gijang-gun coast, hence potential effects of disturbance and environmental pollution should be considered. Seaweed farming in particular - a major activity along the Gijang-gun coast -, together with effects of other anthropogenic activities such as national fishing port development and the coastal improvement project, could have long-term effects on marine algal communities. Therefore, long-term monitoring and management plans for marine algal communities will be required.

• The Journal of Korean Society for Radiation Therapy
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• v.17 no.2
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• pp.133-140
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• 2005

Purpose : This test is designed to identify the validity of treatment plan by implementing real-time dosimetry by means of dose that is absorbed into PTV and OAR when preparing doses of 3D and POP plans. Materials and Methods : In treatment. error can be calculated be comparing Exp. Dose with the actual dose, which has been converted from 'the reading value obtained by placing diode detector on the area to be measured'. Same test can be repeated using Alderson-Rando phantom. Results : Errors were found: A patient(POP plan): 197.6/199=-1.2%, B patient(3D-plan): 199.9/198.7=+0.6%, C patient: 196/200=-1.5%. In addition, considering the resulted value of measuring OAR besides target-dose for C patient showed 96/200, representing does of 47%, the purpose of protection was judged to be duly accomplished. Also it was acknowledged the resulted value of -3.7% met the targeted dose within the range of ${\pm}5%$. Conclusion : Aimed for identifying the usefulness of pre-treatment dose measurement using diode detector, this test was useful to evaluate the validity of curing because it resulted in the identification of category to be protected as well as t dose. Moreover, it is thought to have great advantage in ascertaining the dose of target, dose of which is not calculated yet. Similar to L-gram before treatment, this test is thought to be very effective so that it can bring great advantages in the aspects such as validity of curing method and post-treatment plan as well.

• Korean Journal of Microbiology
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• v.51 no.4
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• pp.374-381
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• 2015

Occurrences of coastal dredged materials are ever increasing due to port construction, navigational course maintenance and dredging of polluted coastal sediments. Ocean dumping of the coastal dredged materials has become virtually prohibited as London Treaty will be enacted as of the year 2012. It will be necessary to treat and recycle the dredged materials that may carry organic pollutants and heavy metals in a reasonable and effective process: collection of the dredged materials, liquid and solid separation, and treatment of organic compounds and heavy metals. In this study we have developed a continuous bioreactor system that can treat a mixture of silt and particulate organic matter using a microbial consortium (BM-S-1). The steady-state operation conditions were: pH (7.4-7.5), temperature ($16^{\circ}C$), DO (7.5-7.9), and salt concentration (3.4-3.7%). The treatment efficiencies of SCOD, T-N and T-P of the mixture were 95-96%, 92-99%, and 79-97%. The system was also effective in removal of heavy metals such as Zn, Ni, and Cr. Levels of MLSS during three months operation period were 11,000-19,000 mg/L. Interestingly, there was little sludge generated during this period of operation. The augmented microbial consortium seemed to be quite active in the removal of the organic component (30%) present in the dredged material in association with indigenous bacteria. The dominant phyla in the treatment processes were Proteobacteria and Bacteroidetes while dominant genii were Marinobacterium, Flaviramulus, Formosa, Alteromonadaceae_uc, Flavobacteriaceae_uc. These results will contribute to a development of a successful bioremediation technology for various coastal and river sediments with a high content of organic matter, inorganic nutrients and heavy metals, leading to a successful reuse of the polluted dredged sediments.

• The Korean Journal of Air & Space Law and Policy
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• v.20 no.1
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• pp.143-209
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• 2005

In 1994, the North Korea indicated their intention to open up airspace. The air route passing through from Daegue FIR to Pyungyang FIR has established in 1996. The air transport cooperation between South and North Korea seemed to be reinforced at the event of President Kim, Dae-Jung's visit to North Korea by passing through a temporarily established Yellow Sea Airway in the year of 2000. The nature characteristics of air transport burdening of many circumstantial situations, however, have kept cooperation between South and North Korea from being facilitated till now. Recently as the more exchange between North and South Korea, the more frequent opportunities to discuss economic cooperation, which in sequence increased political credibility has been increased. The rail, road, and port reconnecting has realized which have been regarded impossible. Furthermore, it is expected to transport personnel and goods through South-North direct connected routes in the near future This study shows several meanings of air transport cooperation between South and North Korea. It will be far beyond simply partial air route connecting in this region, it gives great significance to realize economic cooperation and Northeast hub through air transport industry sector. This will be an exit for air transport industry have suffered limits derived from North Korea troubles and difficulties in growing as Northeast air hub. Namely, South-North air connection denote its meaning in providing opportunities Korea to be Northeast Hub and advanced country having globally competitive air transport industry To develop strategy for air transport cooperation between South and North Korea. they were developed by SWOT analysis on the basis of circumstantial analysis. These strategy need to be commanded properly to the changes of surrounded circumstances. The study result show it is desirable to apply phasal strategies by using strengths, weaknesses, threats and opportunities factors underlying analysis of inner and outer circumstances to cooperate in air transport sector.

• Journal of Chest Surgery
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• v.39 no.5 s.262
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• pp.387-393
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• 2006

Background: Esophageal perforation is an uncommon problem, but it is associated with high mortality. We performed a retrospective review of patients with instrumental esophageal perforation to assess the outcome of current management techniques. Material and Method: We retrospectively analyzed all cases of instrumental esophageal perforation diagnosed at our hospital from January 1999 through to March 2005. The study group consisted of 12 patients (8 women and 4 men) with a mean age of 48.8 years (range, $21{\sim}83$ years). We reviewed the effects of the surgical or medical treatments in various conditions of patients, such as of various sites of perforation and time delayed after injury. Result: Perforations were due to diagnostic endoscopy (50.0%, 6/12), esophageal bougination for benign stricture (33.3%, 4/12), endoscopic port insertion (8.3%, 1/12), and tracheal intubation (8.3%, 1/12). The perforated sites were thoracic in 7 patients and cervical in 5. The treatment included resection and reconstruction (5 cases), incision and drainage (4 cases), medical treatment (2 cases), and closed thoracostomy drainage only (1 case). Post-operative complications of transient pneumonia and wound infection were developed in 1 patient respectively. Both occurred in two patients with diffuse mediastinal abscess formation. The overall mortality was 8.3% (1/12) in one old patient who was managed medically for cervical esophageal perforation. Conclusion: We concluded that surgical treatment for esophageal perforations was safe and effective whether diagnosed early or lately.

• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.2
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• pp.188-196
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• 2023

Among marine accidents caused by bad weather, visibility restrictions caused by sea fog occurrence cause accidents such as ship strand and ship bottom damage, and at the same time involve casualties caused by accidents, which continue to occur every year. In addition, low visibility at sea is emerging as a social problem such as causing considerable inconvenience to islanders in using transportation as passenger ships are collectively delayed and controlled even if there are local differences between regions. Moreover, such measures are becoming more problematic as they cannot objectively quantify them due to regional deviations or different criteria for judging observations from person to person. Currently, the VTS of each port controls the operation of the ship if the visibility distance is less than 1km, and in this case, there is a limit to the evaluation of objective data collection to the extent that the visibility of sea fog depends on the visibility meter or visual observation. The government is building a marine weather signal sign and sea fog observation networks for sea fog detection and prediction as part of solving these obstacles to marine traffic safety, but the system for observing locally occurring sea fog is in a very insufficient practical situation. Accordingly, this paper examines domestic and foreign policy trends to solve social problems caused by low visibility at sea and provides basic data on the need for government support to ensure maritime traffic safety due to sea fog by factually investigating and analyzing social problems. Also, this aims to establish a more stable maritime traffic operation system by blocking marine safety risks that may ultimately arise from sea fog in advance.

• Economic and Environmental Geology
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• v.49 no.4
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• pp.281-290
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• 2016

Coastal areas, used as human utilization areas like leisure space, medical care, ports and power plants, etc., are regions that are continuously changing and interconnected with oceans and land. Regular monitoring of coastal changes is essential at key locations with such volatility. But the survey method of terrestial LiDAR(Light Detection and Ranging) system has much time consuming and many restrictions. For effective monitoring coastal changes, KIOST(Korea Institute of Ocean Science & Technology) has constructed a shipborne mobile LiDAR system. The shipborne mobile LiDAR system, installed in a research vessel, comprised a land based LiDAR(RIEGL LMS-420i), an IMU(MAGUS Inertial+), a RTKGNSS(LEICA GS15 GS25), and a fixed platform. The shipborne mobile LiDAR system is much more effective than a land based LiDAR system in the measuring of fore shore areas without shadow zone. Because the vessel with the shipborne mobile LiDAR system is continuously moved along the shoreline, it is possible to efficiently survey a large area in a relatively short time. We conducted test measurements in the Anmok-Songjung beach around the Gangneung port. Effective monitoring of the changes using the constructed shipborne mobile LiDAR system for seriously eroded coastal areas will be able to contribute to coastal erosion management and response.