• Korean Journal of Ichthyology
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• v.22 no.3
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• pp.195-200
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• 2010

A large volume of hatching jar was tested whether it is an effective to hatch fertilized eggs of Pacific cod. The volume of hatching jar did not show any significant differences in survival of the fertilized eggs; 48.3% for the jar of 15 L and 50.4% for that of 42 L. Survival rate of the fertilized eggs in a large volume of hatching jar ranged from 40.0 to 71.2%, which was higher than those of conventional small circular tank. A higher survival could be achieved even though stocking density of fertilized eggs was as high as 5,000 mL/jar. Consequently, the tested hatching jar allowed for incubation of a greater number of eggs with higher survival rate in a much smaller space. In addition, it reduces costs and manpower, and requires a relatively small amount of water per individual unit (6,700 mL/min), and provides a way to incubate multiple rearing groups in a quarantine environment.

• Journal of Korea Multimedia Society
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• v.3 no.4
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• pp.333-338
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• 2000

MPEG2(or some situations, MPEG is mostly used to change the raw image into the compressed bitstreams for digital image processing. Also these bitsreams are stored in computer for several applications such as multimedia area. Transmission channels have various capacities according to the application area, and the bitstreams stored in computer should be converted in order not to exceed the capacities of a transmission channel. So the problem is how to convert compressed bitstreams of a given bit-rate into compressed bitstreams of other bit-rates. Such a specific transcoding problem in this paper is referred to as bit-rate conversion. Several researches have been done on bit-rate conversion for the bitstreams compressed by MPEG. But the existing schemes are not suitable fort MPEG4 applications because it needs to transmit shape information( which is not necessary for MPEG2) as well as texture information in MPEG4 system. So we propose a new bit-rate converter which considers both texture and shape information.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1994.04a
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• pp.236-236
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• 1994

Acetylsalicylic acid (ASA)와 고려홍삼의 항산화 성분인 maltol을 축합하여 신물질 aspalatone을 합성하고, 흰쥐에서의 지혈시간 연장 효과, 항혈소판 응집 억제 (in Vitro, ex ViVO) 효과 및 생쥐의 혈전 모델을 이용한 항혈전 (in vivo) 효과를 연구하였다. SD계 웅성 흰쥐에 15 mg/kg의 낮은 용량으로 경구투여 할 경우, aspalatone과 ASA는 각각 최소한 8일 연속투여후 지혈시간을 유의적으로 연장시켰으며 같은 용량으로 10일 간 경구투여. 하였을 때, aspalatone 투여군은 대조군에 비하여 지혈시간이 57% (p<0.005) 연장된 반면, ASA 투여군은 44% 연장되었다. 반면, aspalatone의 아세칠 기를 갖지 않는 salicylic acid maltnl ester는 같은 용량에서 지혈시간을 유의적으로 연장시키지 않았다. Aspalatone은 in vitro에서 collagen에 의해 유도된 흰쥐 혈소판 응집을 강력하게 억제하였으나 (IS$_{50}$ = 0.18 mM), ASA와 마찬가지로 ADP에 의한 응집은 억제하지 않았다. Aspalatnne과 다른 대조약물들의 ex vivo에서의 혈소판 응집 억제능은 ASA>dipyridamdle(equation omitted)aspalatone>ticlopidine의 순이었다. 1회 경구투여로 aspalatone은 생쥐의 collagen에 의한 혈전에 기인하는 치사율을 억제하였다 (ED$_{50}$ = 32mg/kg). Aspalatone을 10일 간 투여하면 유효용량이 현저히 감소하여 20 mg/kg에서 치사율을 90% (p<0.001) 억제하였으며, 이러한 항혈전 효과는 투여중단 4일 후에도 지속되었다. 또한, 경구투여시 위궤양을 유발하는 ASA (ulcer index : 29 mm 200 mg/kg p.o.)와는 다르게 aspalatone은 위궤양을 유발하지 않는다는 장점을 갖는다 (0.71 mm, 800 mg/kg p.o.). In vitro에서 malondialdehyde 생성 억제를 지표로 한 aspalatone의 항산화 활성 ($IC_{50}$/ = 0.11 mM)은 maltol ($IC_{50}$/ = 0.084 mM)과 유산하다. 이러한 실험결과를 토대로 하여 aspalatone을 위궤양을 유발하지 않는 항혈전 신약으로 개발하기 위한 연구가 진행 중이다.

• Journal of the Korea Society for Simulation
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• v.25 no.1
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• pp.45-52
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• 2016

In this study, we consider a capacity planning problem of reentrant hybrid flowshops. High-tech electronic products such as semiconductor or TFT-LCD, are produced from manufacturing systems which can be considered as reentrant hybrid flowshops. In the considered capacity planning problem, we determine the number of machines at each stage in the manufacturing system. We introduce criteria indicating which stage needs additional machines or which stage needs reduction of machines considering the characteristics of the product types and the manufacturing system. The objective function of the problem is maximizing throughput rate of the system, of which values are obtained from the simulation model depicting the hybrid flowshops. The performance of the proposed methods were evaluated through a series of computational experiments. The simulation model was also used for conducting the comparison experiments among the proposed method and benchmarks.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.16 no.6
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• pp.244-257
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• 2017

Traffic congestion occurs from drivers' human factors such as driver reaction time, reckless lane change, and inexperienced driving. When Automated Vehicles are introduced, human factors are excluded, resulting in increased average vehicle speed, stabilizing traffic flow, and increasing road capacity. This study analyzed traffic flow changes through traffic volume-speed-density plots, and increased road capacity due to Automated Vehicles. As a result of the analysis, when rate of automated vehicles gests higher, the traffic flow became stable. Additionally, it was analyzed that when all vehicles were automated, the road capacity increased by about 120 %. It is expected that there will be a positive expectation in terms of traffic congestion and traffic demand management due to the introduction of Automated Vehicles.

• Journal of the Korean Electrochemical Society
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• v.27 no.1
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• pp.47-54
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• 2024

In this study, ZIF67/rGO was used to minimize the battery life degradation due to the insulating properties of sulfur and the elution of lithium polysulfide. ZIF67 wrapped in rGO creates more space within the carbon sponge and can hold a large amount of sulfur. The sulfur@ZIF67/rGO composite was synthesized and prepared as a sponge to enhance the sulfur retention capacity. The result showed a high initial capacity, with a value of about 1093 mAh g^-1 and a capacity retention rate of 84% after 100 cycles. The high interaction with sulfur through the complexation of cobalt and carbon confirmed that ZIF67/rGO exhibits high performance as a carrier for sulfur, the anode active material of lithium-sulfur batteries, and the high initial capacity and improved capacity retention rate were confirmed.

• Proceedings of the KOR-KST Conference
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• 2001.02a
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• pp.3-29
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• 2001

본 연구에서는 기존의 대중교통 통행배정모형이 고려하지 않거나 미흡하게 반영하였던 차량과 노선의 용량제약을 고려한 모형의 구축을 시도하였다. 일반적으로 대중교통 통행배정에서 수요와 공급의 관계는 수요가 증가하는 것과 무관하다고 받아들여지고 있으나 용량 초과는 통행자들의 경로선택 및 수단선택에 영향을 끼친다고 볼 수 있다. 이러한 용량초과에 의한 혼잡을 반영하기 위해 용량제약식을 포함한 모형을 개발하고 실용운행회수라는 개념을 도입하였다. 또한 기존에 제시된 용량제약을 고려한 모형들이 실제적인 현상을 정확히 모사하는 데에는 한계가 있을 뿐 만 아니라 현실과 다소 거리가 있는 가정이 내재되어 있는 반면 본 연구에서는 가능한 한 최대로 현실 여건을 반영하는 모형을 정립하였다. 본 연구에서 제시한 모형은 동일한 기종점 사이를 운행하는 경쟁노선이 많은 대도시에서 통근·통학을 위한 통행자들이 많은 오전, 오후 첨두시 대중교통 수요를 분석하여 대중교통의 운행관리체계 개선 및 투자계획, 서비스 개선을 위한 수요예측을 하는데 유용하게 사용할 수 있을 것으로 사료된다. 그리고 기존의 대중교통 통행배정의 결과가 현재나 장래의 잠재적인 수요(demand)를 예측하는 방법인데 반하여 본 연구에서 정립된 모형은 주어진 네트워크에서 실제로 통행하고 있는 수요(flow)를 예측함으로써 교통 계획가나 대중교통 운영자의 계획 및 운영정책수립에 합리적인 도움을 줄 수 있다. 또한 현재의 대중교통 시스템 하에서의 통행배정 뿐만 아니라 다른 형태의 용량과 운행특성을 가진 교통 수단이나 노선이 도입되었을 때 공급이 제한적인 경우의 수요 예측에 적합한 모형을 개발하였다.에 대한 규제가 초국가적 차원으로 발전되는 계기를 제공하고 있다. 향후, 담배규제협약안의 세부사안들에 대한 합의과정에서 각 국별로 상당한 이견과 반발이 예상되고 있지만, 협약안의 전체 회원국 투표에서 승인될 경우 각 국가들뿐만 아니라 담배산업과 담배기업들에게 미치는 파급효과가 매우 클 것으로 예상된다. 대부분의 국제협약들이 그러하듯이, 담배규제협약도 그 적용 범위와 수준이 어느 정도로 결정되는지에 따라 각 국가와 기업별 이해관계가 크게 달라지게 되기 때문에 신중한 대응전략이 요구된다고 하겠다.의 화물전용차선의 설치시는 수답렬 교통량의 구성비와 구간 평균교통량에 의하여 그 효과가 다르게 나타남을 알 수 있었다. 따라서 물류비용 절감차원에서의 화물전용차선의 설치는 본 연구에서 나타낸 방법과 같이 수단간의 경제적 편익을 고려한 구간별 시간대별 효과분석을 통하여 정책의 시행여부가 결정되어야 할 것이다. 한편, 화물전용차선의 설치로 인한 물류비용의 절감을 보다 효과적으로 달성하기 위해서는 종합류류 전산망의 시급한 구축과 함께 화물차의 적재율을 높이고 공차율을 낮출 수 있는 운송체계의 수립이 필요한 것으로 판단된다. 그라나 이러한 화물전용차선의 효과는 단기적인 치유책일 수밖에 없기 때문에 물류유통 시설의 확충을 위한 사회간접자본의 구축을 서둘러 시행하여야 할 것이다.으로 처리한 Machine oil, Phenthoate EC 및 Trichlorfon WP는 비교적 약효가 낮았다.>$^{\circ}$E/$\leq$30$^{\circ}$NW 단열군이 연구지역 내에서 지하수 유동성이 가장 높은 단열군

• Clean Technology
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• v.24 no.4
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• pp.332-338
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• 2018

Currently graphite is used as an anode active material for lithium ion battery. However, since the maximum theoretical capacity of graphite is limited to $372mA\;h\;g^{-1}$, a new anode active material is required for the development of next generation high capacity and high energy density lithium ion battery. The maximum theoretical capacity of Si is $4200mA\;h\;g^{-1}$, which is about 10 times higher than the maximum theoretical capacity of graphite. However, since the volume expansion rate is almost 400%, the irreversible capacity increases as the cycle progresses and the discharge capacity relative to the charge is remarkably reduced. In order to solve these problems, it is possible to control the particle size of the Si anode active material to reduce the mechanical stress and the volume change of the reaction phase, thereby improving the cycle characteristics. Therefore, in order to minimize the decrease of the charge / discharge capacity according to the volume expansion rate of the Si particles, the improvement of the cycle characteristics was carried out by pulverizing Si by a dry method with excellent processing time and cost. In this paper, Si is controlled to nano size using vibrating mill and the physicochemical and electrochemical characteristics of the material are measured according to experimental variables.

• Resources Recycling
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• v.33 no.3
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• pp.3-11
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• 2024

This study addressed the cost structure of metallurgical plants for vanadium recovery or production, which were previously planned or implemented. Vanadium metallurgy consists of several sub-processes such as such as pretreatment, roasting, leaching, precipitation, and filtration, in order to finally produce vanadium pentoxide. Here, lots of costs should be spent for such plants, in which these costs are largely divided into CAPEX (Capital Expenditure) and OPEX (Operational Expenditure). As a result, the capacities (feed input rates) and vanadium contents are various along the target projects for this study. However, final production rates and grades of vanadium pentoxide showed relatively small differences. In addition, a noticeable correlation is found between capacities and specific operating costs, in that a steadily decreasing trend is described with a non-linear curve with around -0.3 power. Therefore, for the plant capacity below 100,000 tons per year, the specific operating cost rapidly decreases as the capacity increases, whereas the cost remains relatively stable in the range of 0.6 to 1.2 million tons per year of the capacity. From a technical perspective, effective optimization of the metallurgical process plant can be achieved by improving vanadium recovery rate in the pre-treatment and/or roasting-leaching processes. Finally, the results of this study should be updated through future research with on-going field verification and further detailed cost analysis.

• Korean Journal of Soil Science and Fertilizer
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• v.34 no.2
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• pp.110-116
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• 2001

This experiment was carried out to investigate the effects of amount of nitrogen application with the barley straw application on the changes in soil physical and chemical properties. nutrient uptake and percentage recovery of chemical fertilizer N in the rice plant from 1997 to 1998. The soil physical properties, such as bulk density, hardness, porosity and gaseous phase were improved by barley straw application. There was also improvement or increment in the soil chemical properties, such as pH, organic matter, T-C. T-N, available $SiO_2$, exchangeable K and cation exchange capacity, but decrease in available $P_2O_5$. The $Fe^{+{+}}$ content in soil after barley straw application was high from tillering stage to panicle forming stage, but becoming lowered toward the heading stage, while $Mn^{+{+}}$ content was increased. N uptake with barley straw application was increased in the N $126kg\;ha^{-1}$ plot, but decreased in the N $141kg\;ha^{-1}$ plot. The uptake of fertilized N was continued longer in barley straw application than none-application plot. Percentage recovery of chemical fertilizer N in rice straw was around 1% at tillering stage, but was highly increasing till maximum tillering stage, while the recovery was generally low in barley straw application. Meanwhile, fertilizer P uptake in barley straw application was high, but potassium uptake was low at all different levels of N application.