• Journal of Korea Port Economic Association
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• v.24 no.4
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• pp.47-70
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• 2008

The purpose of this study is to estimate total factor productivity(TFP) growth by stochastic frontier function and to grasp contributing factors of its growth rate by decomposing the total factor productivity into efficiency change, technical progress, scale change, and allocation change. Annual growth rate of total factor productivity for 1990-2003 is 0.019 (1.9%), higher than that of overall industry (0.010). The main component of TFP growth is not efficiency change but technical progress. Contributing factors of total factor productivity growth are change of allocation efficiency in port industry, technical progress in sea-transportation industry, and change of scale efficiency in transportation-equipment industry. The change of total factor productivity shows a decreasing trend since late in the 1990s. The annual technical efficiency of port-logistics industry is less than that of overall industry. Capital elasticity for output (0.391) is higher than labor elasticity (0.227), but scale economy of port-logistics industry is 0.618, which is far from optimal scale economy.

• Journal of Ginseng Research
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• v.26 no.4
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• pp.202-205
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• 2002

This study was carried out to investigate the optimum conditions for extraction of acidic polysaccharide from red ginseng marc produced by manufacturing alcoholic and water extract from red ginseng. Extraction efficacy of acidic polysaccharide from dried red ginseng marc was higher than that before drying. The appropriate conditions for the extraction of acidic polysaccharide from red ginseng marc were particle size under 3.35 mm after drying red ginseng marc, 1∼2 hours of extraction time and 2∼3 extraction times, respectively. The amount of acidic polysaccharide in water extract from red ginseng marc treated with $\alpha$-amylase and cellulase increased about 20∼50%. From the above resuts, we suggest that red ginseng marc produced by manufacturing alcoholic and water extract of red ginseng has higher potencies in the utilization of waste materials.

• Journal of the Korean GEO-environmental Society
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• v.15 no.12
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• pp.15-24
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• 2014

This study was performed to investigate the removal characteristics of heavy metals in Acid Mine Drainage (AMD) using pellet-type Zeolite-StarFish ceramics (ZSF ceramics), in which natural zeolite and starfish were mixed and calcined with wood flour. Kinetic experiment showed the removal reaction of heavy metals by ZSF ceramics reached the equilibrium status within 3 hours. The optimal calcination temperature range for removal of heavy metals was measured to be $800{\sim}1,000^{\circ}C$. The calcination time had little effect on the removal of heavy metal in AMD. The adequate dose of ceramics was shown to be 1.0~1.2 % for removal of heavy metals in AMD. High removal efficiencies of heavy metals (Al, As, Cd, Cu, Fe, Mn, Zn) in AMD, more than 95 % except for Pb, were obtained under the condition of dose of ceramics more than 1.0 %. The removal efficiencies of heavy metals increased with increasing mixing concentration of wood flour. The adequate mixing concentration of wood flour was observed to be 10 %. The batch experimental results exhibited that the ZSF ceramics could act as an efficient ceramics for removal of heavy metals in AMD and the wood flour could provide porous ZSF ceramics with enhanced removal efficiency of heavy metals.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.16 no.3
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• pp.216-224
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• 1983

This work was undertaken to obtain some characteristics of proteolytic enzyme of marine gastropods such as sea hare, Aplysia kurodai, top shell, Turbo cornutus, and abalone, Haliotis discus hannai. An influence of pH, temperature and some chemicals on proteolytic activity of the crude enzyme extracted from digestive tract of the samples was taken into account and the stability of the enzyme during the storage at low temperature was also discussed. In comparison of the activities of the crude enzyme from the samples to the optimum conditions, it was characterized that abalone has twice or the more times higher activities than the other two species of the gastropoda in the acid and weak acid region, while, in the alkaline region, sea hare has six or the more times higher acitivities than the other two species. The proteolytic activity was facilitated by $Mn^{2+}$, some reducing agents, EDTA and DTT, and inhibited by $Hg^{2+}$ and SDS, but the other chemicals were not significantly affected to the activity. The low temperature storage of the enzymes of sea hare and top shell at $0^{\circ}C\;or\;-20^{\circ}C$ was not affected to the enzymic activity under the optimum pH condition except in the alkaline region. On the other hand, the low temperature storage was brought about no significant effect on the activity of the enzymes extracted from abalone under the optimum condition of the weak acid region, but apparently influenced to the activity under the optimum condition of the acid and alkaline region.

• Korean Journal of Plant Tissue Culture
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• v.26 no.2
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• pp.77-83
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• 1999

We have investigated the effect of culture conditions on tropane alkaloids (scopolamine, hyoscyamine) production in hairy root cultures of Hyoscyamus niger L. induced by Agrobacterium tumefaciens $A_4$T. SH medium was the best for tropane alkaloids production from the hairy root clones, HN18 and HN57. The optimum culture peroid was 5 weeks for HN18 clone and 6 weeks for HN57 clone, respectively. The optimum sucrose and dextrose concentrations in tropane alkaloids productivity were 3% and 2%, respectively. The growth of both HN18 and HN57 clones increased with as sucrose concentration increase up to 7% sucrose, but tropane alkaloid contents was significantly decreased. In the HN18 clone, the optimum concentration of sucrose for alkaloids productivity was 5% and those of dextrose was 2%. The productivity of tropane alkaloids for HN57 clone under dextrose treatments was quite a low level compared to sucrose treatments.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.2
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• pp.135-140
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• 2017

The demand for aquatic products in the domestic and overseas is increased, so that the aquaculture industry can achieve high performance by controlling and standardizing the production even with a relatively small amount of resources compared with existing fisheries. However, traditional method has problems of low productivity such as natural disasters and ecosystem pollution, and it is necessary to develop a new culture system that can move to the optimal culture site. In order to find the optimal location, you need to collect and analyze the necessary data such as temperature and DO in real time. Data analysis was performed by using K-means clustering method based on machine learning, so that it was possible to decision when and where to move the farm by repeated unsupervised learning. The proposed research could solve the problems of low productivity such as natural disasters and ecosystem pollution if applied to regressive fish farmers.

• Transactions of the Korean Society of Mechanical Engineers
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• v.10 no.4
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• pp.463-470
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• 1986

본 연구에서는 절삭공정 중 발생하는 공구의 접촉이탈 현상에 의하여 공작 물의 절삭된 표면중에 한회전 및 그 이전 회전에 절삭된 절삭면의 형상이 현재의 절삭 깊이에 영향을 미치는 다중재생효과(multiple regenerative effect)가 존재하는 선삭 작업에서 공구의 착탈현상을 고려한 비선형채터(nonlinear chatter)를 공작기계의 생 산성의 관점에서 절삭공정의 특성을 고려하여 해석하였으며, 수동제어기의 일종인 임 펙트댐퍼를 절삭공정에 응용하여 절삭작업중에 공작기계의 안정성향상 뿐만 아니라 생 산성의 증가효과를 규명하였다.아울러 댐퍼자체의 설계변수에 따른 채터 억제효과 를 고려하여 최적의 댐퍼를 설계하는 방법을 제시하였다.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.4
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• pp.736-740
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• 2004

Preparation of ginseng concentrate with high content of acidic polysaccharide from white tail ginseng marc that was obtained after preparation of white tail ginseng extract. As a result of extraction of white tail ginseng under various concentrations of ethanol (0∼90%), both amount of acidic polysaccharide and extraction yield decreased by increasing the ethanol concentration. However, acidic polysaccharide extracted by water from white tail ginseng marc was increased in accordance with the increase of ethanol concentration. The optimal condition for the extraction of acidic polysaccharide from the marc was treatment of $\alpha$-amylase in 390∼650 unit/g residue/15 mL of distilled water for 5 min at 4$0^{\circ}C$. The amount of acidic polysaccharide in water extract of the marc was increased from 8.3% to 10.5% by the treatment of $\alpha$-amylase. A new ginseng extract mixture was manufactured by mixing 50% ethanol extract of white tail ginseng and water extract of alcoholic residue in the ratio of 8:2 (w/w). Crude saponin content and acidic polysaccharide content were 10.5% and 17%, respectively. The mixture had a same crude saponin content and twice acidic polysaccharide content comparing to 50% ethanol extract of white tail ginseng. It suggests that preparation of new ginseng concentrate with high content of acidic polysaccharide from white tail ginseng marc has high potencies in the utilization of waste material.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.16 no.4
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• pp.319-325
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• 1991

A nonparametric detection scheme which uses rank statistics for detection of known signals is considered in a special case of a generalized observation model. Specifically locally optimum rank detectors for detection of known deterministic singals in a singnal-dependent noise model are derived, and compared to those derived for the purely-additive noise model. Examples of the score functions are given, which constitutes the test statistics of the locally optimum rank detectors.

• Journal of Soil and Groundwater Environment
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• v.10 no.3
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• pp.16-23
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• 2005

In order to remediate acid mine drainage (AMD) from the Jeongam coal mine, steel mill slag, cow manure and limestone were used. As a result of batch test, the proper amounts for treating 1 L of acid mine water from the mine were determined as 15 g of steel mill slag, 15 g of cow manure and 500 g of limestone. After feasibility test, remediation system was arranged in the order of steel mill slag tank combination of cow manure and limestone, precipitation tank and oxidation tank. During 54 days' operations, the pH values of the treated waters increased from 3.0 to 8.3 and 61 % of sulfate concentration in an initial water was decreased. In addition, the removal efficiencies for metals in the water were nearly 99.9% for Al, Fe, Zn and 92.6% for Mn. Thus, the combination of steel mill slag, cow manure and limestone can be used as neutralization 때d metal removal for acid mine drainage.