• Biomolecules & Therapeutics
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• v.3 no.2
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• pp.104-110
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• 1995

Arachidonic acid (AA, C20 : 4, $\omega$-6) and eicosapentanoic acid (EPA,C20 : 5, $\omega$-3), which are polyunsaturated fatty acids forming eicosanoids, were tested for their effects on blood pressure in Wistar rats and SHR. AA is the most important precursor for the biosynthesis of eicosanoids which include the prostaglandins, prostacyclin (PGI$_2$), thromboxane $A_2$ (TXA$_2$) and the leukotriens. TXA$_2$is a potent vasoconstrictor and a powerful inducer of platelet aggregation causing myocardial infarction and hypertention. In contrast, PGI$_2$ induces vasodilation and inhibits platelet aggregation. In this study, AA markedly increased blood pressure, but its effect was antagonized by both EPA, a structural analog of AA, and dazmegrel, a TX synthetase inhibitor. Also, AA enhanced the antihypertensive effects of hydralazine and captopril, and EPA reduced TXA$_2$ production. These results indicate that the hypotensive effects of EPA might be closely related to the decrease in TXA$_2$ biosynthesis due to competitive inhibition by structural similarity of the EPA to the AA, the precursor of TXA$_2$.

• Magazine of the Korean Society of Agricultural Engineers
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• v.45 no.2
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• pp.126-137
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• 2003

The feasibility study of UV-disinfection system was performed for disinfection of effluent from wastewater treatment plant. Three low-pressure UV lamps of 17, 25, and 41 W were examined with various flow rates. Low-pressure UV lamps of 17W were examined with various turbidity, DOM (dissolved organic matter), and SS (suspended solid). The pilot plant was a flow-through type UV-disinfection system, and the range of exposure time varied from 5 to 40 seconds, turbidity from 0 to 40 NTU, DOM from 0 to 30 mg/L, and SS from 10 to 40 mg/L. The 41W lamp demonstrated complete disinfection showing no survival ratio in all the experimental conditions, and generally 17W and 25W lamps also showed high removal ratio over 97%. For the same UV dose (UV intensity times exposure time), high intensity-short exposure conditions showed better disinfection efficiency than low intensity-long exposure conditions. While the effects of turbidity and DOM were not apparent, the effects of SS was significant on the disinfection efficiency which indicates that SS control before UV-disinfection appears to be necessary to increase removal efficiency. Considering characteristics of effluent from existing wastewater treatment plants, cost-effectiveness, stable performance, and minimum maintenance, the flow-through type UV-disinfection system with high intensity and low-pressure lamps was thought to be a competitive disinfection system for wastewater reclamation.

• The Journal of Fisheries Business Administration
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• v.39 no.3
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• pp.49-65
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• 2008

In Korea, deep-sea fishing industry is faced with pressure of being thrown out of business, because of the upcoming unfavorable business conditions such as the fishing regulation of coastal countries, Korea-US Free Trade Agreement(KORUS FTA), and the other socio-economic changes. Hence, we present an evaluation of future business competitive for the deep-sea fishing industry so that the government can develop a concession plan for the deep-sea fishing industry by utilizing the results of this study. In efficiency analysis of deep-sea fishing industry, the decision maker may have two problems: (1) how to deal with multiple inputs and outputs of deep-sea fishing industry and (2) how to assign the weights on different inputs and outputs, In this paper, we proposed to use Data Envelopment Analysis (DEA) to estimate efficiency of deep-sea fishing industry with multiple inputs and outputs. In the DEA, The direct impact of KORUS FTA, fishing regulation of coastal countries, fishing charges, and competitive fishing conditions were used as input parameters while the profitability and secured fishing quarters, as outputs. The results of DEA-BCC model indicate that 6 out of 12 DUMs have better efficiency under variable return to scale assumption.

• Knowledge Management Research
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• v.19 no.4
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• pp.77-98
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• 2018

The purpose of this paper is examine the existing relations structure and IT use for collaboration activities on supply chain and their impacts on the performance of supply chain. This study made a design of the research model that was further constructed by integrating the relationship structure, IT exploration, IT exploitation, supply chain collaboration, absorptive capacity, and knowledge creation, efficiency and efficient. The survey data were collected from 378 companies, where firms are facing increased global competitive pressure and heavily utilize SCM to retain their competitive advantages. The authors validated a measurement model with structural equation modelling and tested eight hypotheses. As a result, the absorptive capacity was closely related to trust, IT exploitation and IT exploration, but supply chain collaboration. Examining the effect of supply chain collaboration with two types of absorptive capacity, the authors found positive effect on potential absorptive capacity, but a non-significant effect on realized absorptive capacity. This finding suggests that the improving performance of supply chain not only is related to the relations structure and IT use on supply chain, but also is closely related to the absorptive capacity.

• International Journal of Quality Innovation
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• v.7 no.1
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• pp.60-89
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• 2006

In the Knowledge-based Economic Era, all of the enterprises are facing global competitive pressure. The activities of knowledge accessing, codifying, and application will obviously become the main inner function on enterprise operation. Knowledge will be the primary competitive advantage; therefore, he who wants to hold the competitive advantage should do the knowledge management (KM) very well. In this study, we construct the research dimensions and variances by the successful factors of KM, which had been practiced very well by big enterprises inside and outside our country, and which was recommended by the related scholars. In order to approach the differences between big enterprises and small and medium-sized enterprises (SMEs) towards implementing KM, this study takes the way of questionnaire investigation to do empirical analysis and to construct the model of KM by path analysis. The study found out when implementing KM, SMEs should highlight 'leadership,' 'library-architecture,' and 'corporate culture' these three aspects, while 'information technology' and 'performance evaluation' these two aspects show no remarkable influence. It shows that he who wants to construct KM might not too overweight on information technology to build the KM system. Therefore, we suggest when implementing KM, enterprises should reinforce the corporate culture by sharing, organized KM process, learning environment for all employees, and highly authorization by top managers in order to reach the expectant success of KM. The result of this study offers practical thinking directions to reach the expectant success for the policy makers in SMEs, who are accessing to or evaluating to implement KM.

• Composites Research
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• v.21 no.1
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• pp.1-7
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• 2008

Composite vessels for high pressure gas storage are commonly used these days because of their competitive weight reduction ability maintaining strong mechanical properties. To supplement permeability of composite under high pressure, it is usually lined by metal, which is called a Type 3 vessel. However, it has many difficulties to design the Type 3 vessel because of its complex geometry, fabrication process variables, etc. In this study, therefore, GUI (graphic user interface) optimal design code for Type 3 vessels was developed based on semi-geodesic algorithm in which various factors of geometry and fabrication variables are considered and genetic algorithm for optimization. In addition, hydrogen vessels for 350/700 bar that can be applied to FCVs(fuel cell vehicles) were designed using this code for verification.

• Journal of Distribution Science
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• v.14 no.3
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• pp.73-83
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• 2016

Purpose - The parcel delivery service(courier) industry all over the world has been expanding its market so far, but its growth has been declining in recent years. In this situation, most parcel delivery companies are having trouble with managing themselves because of the pressure from the customer to increase service level and decrease the rate. The purpose of this study is to provide ways to improve competitive advantages of the parcel delivery service industry by evaluating the multi-period operating efficiency of Korea, Japan and global service providers. Research design, data, and methodology - The data for the period of 2011 to 2014 were collected from the annual reports published by parcel delivery companies. In this study, we analyze the marketability (revenue), profitability (operating profits), and management conditions (net profits) of parcel service companies by combining information on human resources (number of employees) and material resources (total assets and equity). Therefore, the number of employees, total assets, and equity are selected as input variables, and revenue, operating profits, and net profits as the output variables. In this study, DEA (Data Envelopment Analysis) is used to measure the comparative efficiency and MPI (Malmquist Productivity Index) is used to analyze the trend of change of the efficiency for a multi-year period. Results - The operational efficiency scores of medium-sized parcel delivery companies in Korea are higher than other larger competitors such as Korean, Japan and Global larger companies. As of 2014, Logen(1.878) was found to be the most efficient parcel delivery enterprise, followed by KGB (1.224), and Kyoungdong(1.002). Otherwise, Hanjin(0.235), CJ(0.262), Hyundai Logistics(0.657), DHL(0.611), UPS(0.766), FedEx(0.498), TNT(0.350), Yamato(0.762) and Sagawa(0.520), larger sized companies, were done inefficiently. The productivity of parcel delivery companies is influenced by endogenous factors as well as exogenous ones such as changes in business environment and technological advances. Conclusions - Korean medium-sized companies have relatively high efficiency scores in operation. That is why they still survive the competitive market in Korea where market restructuring on the industry has been expected to be conducted for many years. The reason why medium-sized couriers had higher efficient scores than larger couriers is that most of couriers spend more operating expenses versus unit price of delivery which is the amount of money that is needed in order to send a package by parcel service. So the delivery unit price must be taken into account by all the expenses associated with the cost of fuel, labor and maintenance expenses for facilities, etc. therefore, the unit price must be increased to strengthen business competitive power. In order for the industry to have more competitive advantage, the companies need to make profits by increasing demand volume and raising the delivery rate to provide high-quality delivery service to customers. And both endogenous and exogenous change must take precedence in order to strengthen their competitiveness.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.05a
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• pp.315-318
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• 2003

Recently, condenser tube which is used for a cooling system of automobiles is mainly manufactured by the conform extrusion but this method is inferior as compared with direct extrusion in productivity per the unit time and in the equipment investment. Therefore, it is essential for the conversion of direct extrusion with porthole die. The direct extrusion with porthole die can produce condenser tube which has the competitive power in costs and qualities compared with the existing conform extrusion. This study is designed to evaluate metal flow, welding pressure, extrusion load tendency of mandrel deflection that is affected by variation of porthole shape in porthole die. Estimation is carried out using finite element method under the non-steady state. Also this study was examined into the cause of mandrel fracture through investigating elastic deformation of mandrel during the extrusion.

• The Journal of Information Systems
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• v.25 no.4
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• pp.63-85
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• 2016

Purpose While the popularity of C2C auction platforms such as eBay is gradually decreased, this domain is still undermined to explain online bidding behaviors. Online bidders sometimes engage in impulsive bidding due to some of the online auction characteristics. Therefore, this study develops and tests a model of the impulsive bidding exhibited by online bidders in C2C auction platforms. Based on S-O-R framework, our model posits that both perceived time-pressure and competition intensity affect cognitive absorption which ultimately influences the impulsive bidding. Design/methodology/approach This study collected survey data from 214 C2C auction participants, who have prior experience on impulsive bidding and tested both measurement model and structural model by using CB-SEM (covariate-based structural equation modelling) technique. In this study, by using AMOS 20.0, we tested the measurement model for its overall fit, item reliability, and validity and further conducted the structural model to test our proposed hypotheses. Findings Based on our results, we found that perceived tim-pressure and competition intensity were positively related to cognitive absorption. We also found that the cognitive absorption was positively associated with impulsive bidding behavior. In this study, by developing our research model in S-O-R framework, we provide an alternative theoretical mechanism to describe online impulsive bidding behavior.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.29 no.8 s.239
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• pp.1146-1152
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• 2005

Recently, multi cell tube which is used for a cooling system of automobiles is mainly manufactured by the conform extrusion but this method is inferior as compared with direct extrusion in productivity per the unit time and in the equipment investment. Therefore, it is essential for the conversion of direct extrusion with porthole die. The direct extrusion with porthole die can produce multi cell tube which has the competitive power in costs and qualities compared with the existing conform extrusion. This study is designed to evaluate metal flow, welding pressure, extrusion load, tendency of mandrel deflection that is affected by variation of porthole shape in porthole die. Estimation is carried out using finite element method under the non-steady state. Also this study was examined into the cause of mandrel fracture through investigating elastic deformation of mandrel during the extrusion.