• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.4 no.4
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• pp.275-288
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• 1999

To understand the effects of ocean-dumping of organic wastes on bacteria, bacterial abundance and production, and hydrolytic activities of aminopeptidase (AMPase) and ${\beta}$-glucosidase (${\beta}$-GLCase) were measured 5 times in the euphotic zone of the dumping and non-dumping areas of the East Sea from April 1996 to September 1997. Comparing the depth-integrated values of phytoplankton biomass and bacterial parameters over the euphotic zone of dumping area with those of non-dumping area, we found that activities of ${\beta}$-GLCase in the oceanic dumping area were always higher than those in the oceanic non-dumping area. Also, thymidine-based bacterial production always correlated significantly with leucine-based bacterial production in dumping area (balanced growth), but not in non-dumping area (unbalanced growth). These results seem to be bacterial responses to continuous dumping of organic matter into the dumping area. Further, a relationship between bacterial abundance and production was significant in dumping area, but insignificant in non-dumping area, indicating that control mechanisms of bacterial abundance were different in two areas. Relationships between other bacterial parameters varied with areas and seasons, suggesting that bacteria might be regulated by different factors in spring and summer. Further studies are required to test whether these seasonal variabilities of regulating factor are associated with changes in temperature, temperature-related phenomena, or characteristics of wastes.

• Journal of Korean Society of Transportation
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• v.25 no.6
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• pp.141-157
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• 2007

This paper evaluates the effects of privatization and deregulation on the firm-specific efficiency and total factor productivity (TFP) growth in the Korean and Japanese railways. Using a stochastic frontier approach and a generalized translog functional form, the paper specifies the equation system consisting of a multiproduct variable cost function and input share equations which is estimated with Zellner's iterative seemingly unrelated regression and the corrected least squares method. The Korean and Japanese railway firms are assumed to produce three outputs (Shinkansen passenger-kilometers, incumbent railway passenger-kilometers, ton-kilometers of freight) using three input factors (labor, fuel, maintenance and rolling stock). A monetary value of the ways and fixed installations held by the railroad firm is also included as a quasi-fixed input. The empirical results indicate that the average estimate of cost inefficiency is 2.57% for the total sample and on the average, JNR and JR Kyushu are found to be worst efficient while the most efficient railway firm in the sample is JR West. Also the cost efficiency levels of seven JRs have been improved after the reform and privatization of JNR. The findings also indicate that TFP growth of the privately-owned JRs are higher than those of the government-owned KNR and JNR. Three-island JRs and JR Freight have slightly higher TFP growth than Honshu JRs as well. Thus, the results suggest that managerial autonomy and increased competition via deregulation have improved efficiency and TFP growth.

• Journal of Technology Innovation
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• v.22 no.1
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• pp.89-117
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• 2014

Employing female in the field of science and engineering is becoming increasingly important with diversity and creativity emerging as key factors to build Creative Economy. Under these circumstances, it is necessary to recognize and discourage gender discrimination in the labor market by analyzing wages - the market value of labor which determines one's economic status. This study uses the Oaxaca-Ransom decomposition (1994) to analyze the gender wage gap and identify factors influencing the pay gap in science and engineering labor force. The results of this study are as follows: First, the average wage of female scientists and engineers reaches only 65% of that of male labor force, and the male scientist and engineers are superior in terms of personal attributes, for instance, education background. Second, looking at the factors that influence wages, wage premiums are associated with higher education background, older age, longer period of service, and weekly working hours for both male and female in managerial positions. Third, the wage decomposition shows that in the case of science and engineering labor force, the productivity difference by personal attributes reaches about 58%, and gender discrimination by the characteristics of the labor market stands at about 41%. This means the wage gap by productivity level in science and engineering labor force is wider, and the gender gap is smaller compared to non-science and engineering fields. However, the results of an analysis on specialties and education background of male and female scientists and engineers suggest that the discrimination against women is more serious when the percentage of the female labor force is low and the percentage of temporary workers in the labor market is high. In order to eliminate this discrimination, it is necessary to reduce the imbalance of female scientists and engineers in the labor market, among others, while female scientists and engineers, themselves, need to make continuous efforts to strengthen their capabilities.

• Journal of Veterinary Clinics
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• v.28 no.6
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• pp.581-585
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• 2011

Either the fasting during natural molting or the starvation in induced molting would be a severe metabolic stress to laying hens. The metabolic stress during starvation and subsequent refeeding syndrome could lead to unbalance of mineral homeostasis, including $Mg^{2+}$, $K^+$ and P required by ATP synthesis. Since $Mg^{2+}$ is a fundamental ion for normal metabolic processes and stress may not only increase in demands of $Mg^{2+}$ but also produce consequence of $Mg^{2+}$ deficiency, we investigated the changes of blood ionized and total ions related to starvation during molting in laying hens. We founded the significant decrease in blood $Mg^{2+}$ and $K^+$ accompanied by the changes of biochemical parameters relating to increased metabolic stress after molting. These results suggested that appropriate $Mg^{2+}$ and $K^+$ supplements to laying hens could have beneficial effects during molting and subsequent refeeding that could produce a severe hypomagnesemia and hypokalcemia.

• Journal of Veterinary Clinics
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• v.30 no.1
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• pp.5-11
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• 2013

Acute gastric ulcer is caused by the unbalance between cell proliferation and apoptosis in gastric mucosa. Platycodin D (PD) has been reported to have a variety of pharmacological properties, including antioxidant and antiin-flammatory effect. In the present study, we investigated the protective effect of PD on the basis of cell proliferation/apoptosis and cyclooxygenase-2 (COX-2) expression in the acute gastric ulcer induced by ibuprofen in Rats. Acute gastric damage was induced by the repeated treatment of ibuprofen (200 mg/kg) with 8 hrs interval in a day. PD was orally administrated at concentrations of 2.5 and 5 mg/kg every day for 5 days before the induction of acute gastric ulcer. Macroscopically, ibuprofen caused a significant increase in the number of lesions in the gastric mucosa. But pretreatment of PD significantly reduced ibuprofen-induced gastric lesion score and prevented excessive mucus depletion in gastric mucosa. Also, pretreatment of PD counteracted significantly Ki-67 decrease in the proliferating zone of gastric glandular portion and highly reduced or delayed apoptotic cells on TUNEL assay. In addition, COX-2 expression was increased in gastric mucosa bearing erosions or ulcers but pretreatment of PD reduced COX-2 expression in gastric lesions. These results show that pretreatment of PD has a protective effect against ibuprofen-induced gastric damage, not only by counteracting a decrease of cell proliferation, but also by inhibiting or delaying apoptosis via regulation of COX-2 within the gastric mucosa.

• Journal of Korea Water Resources Association
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• v.45 no.5
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• pp.445-454
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• 2012

The present study aims to investigate the long-term channel morphological changes derived from channelization, embankment and levee construction works in unregulated fluvial channel of the Jiseock River. Analyses of aerial photographs taken past (Year 1966) and recent (Year 2002) showed the temporally remarkable changes in channel planform such as channel shape, bar migration, vegetation encroachment in bar. During the period, the natural single threading changed into braided types together with decreasing sinuosity by 9.2%, increasing vegetation occupied bar ranged 97% of total bars area. Because such channel morphological changes are closely similar to those in dam downstream channels, we assume that both/either flow regime alteration and/or sediment transport discontinuity may be critical for the fixed channel and spread of vegetated bars even in unregulated river without dam reservoir upstream. We found more reduced frequency and magnitude of flooding water level comparing with past, but no significant alteration of inter annual water level variation. Bed material has been coarsened by 4~5 times and the riverbed has been degraded in overall channel but aggraded locally in conjunction reach of tributaries. The results indicates that reduced sediment dynamics in fluvial channel which derived by bed material coarsening, river bed degradation and unbalanced sediment transport capacity between tributary and mainstem can be a causal factor to trigger channel morphological changes even in unregulated rivers.

• Land and Housing Review
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• v.6 no.4
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• pp.195-213
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• 2015

Recently, there has been changing the housing rental market paradigm structure which has been increased the ratios of partly monthly rental ratios, because of increasing chonsei's price, the preference of monthly rental and the rack of chonsei's supply amount. This study had done a survey of 1,400 people for private and public rental residents by region and housing types during Dec. 2014. According to the result of survey, Market participant prospect strongly to change chonsei to monthly rental market structure and the reason of rising of chonsei's price is the preference of householder's monthly rental because of decreasing interest rate and the rack of chonsei's supply amount. The housing policy's proposal of the stability of low income class's housing and jense's price strongly recommended the expansion of public rental housing supply and the activation of private rental housing, the expansion of chonsei loan, housing boucher etx. The rental market policy for high income class have desired to market autonomy than public side's intervention, on the other hands, the rental market policy for low income class have strongly need to the public side's intervention such as the contiuneous long-term rental housing supply.

• Journal of Intelligence and Information Systems
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• v.8 no.1
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• pp.103-117
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• 2002

Recently, many researchers have developed applications for automated contract and negotiation using agent technologies on electronic commerce. Especially, they have tried to study negotiation mechanism applying agent instead of buyers and sellers. Traditional researches, however, often had limitations. In the researches of automated negotiation, the agents had to negotiate with the other agents for a simple negotiation issue because the mechanisms were naive. In the researches of negotiation by user interaction, the agents did not have supported the procedures and methodologies for making the automated negotiation but only supported the users by providing communication environment during the negotiation process by users. In this paper, we propose efficient negotiation model using the modified negotiation model of the game theory. In the proposed model, the agents negotiate automatically with the partner agent and make good benefits by the strategic method during the negotiation process. Each agent makes negotiation issues with user's requirements and exchanges its suggestion alternatively in each step of the negotiation process. The agent evaluates degree of satisfaction for the opposite's suggestion and uses it in the next step of suggestion. To find out the negotiation strategies of opposite side, the agent uses teaming by weights of issues. As a result, the agent improves each own benefits for the contract and reduces the unbalance of its benefits through the proposed negotiation mechanism. We implement the negotiating agents according to the proposed mechanism and prove the efficiency of the proposed model by various experimentation.

• KSBB Journal
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• v.24 no.6
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• pp.521-526
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• 2009

Fatty acid is an important component of many biological processes. However, an imbalance in diet-especially, a n-3 polyunsaturated fatty acids (PUFAs) deficiency-causes several diseases such as diabetes, cardiovascular disease and cancer. In this study, we analyzed the fatty acid contents and compositions of 26 species of Korean salt marsh plants and found high fatty acid contents from S. herbacea ($148.75\;{\mu}g$/mg-dry wt.), S. komarvii ($119.05\;{\mu}g$/mg-dry wt.), C. heterocarpa ($79.23\;{\mu}g$/mg-dry wt.), A. capillaris ($71.65\;{\mu}g$/mg-dry wt.), and L. tetragonum ($67.02\;{\mu}g$/mg-dry wt.). In the case of saturated fatty acids (SFAs) composition, palmitic acid is richest in most salt marsh plants. On the other hand, oleic acid and linoleic acid are major components of monounsaturated fatty acid and n-6 PUFA, respectively. In addition, n-3 PUFAs such as LNA (linolenic acid), EPA (eicosapentaenoic acid), and DHA (docosahexaenoic acid) known as the main fatty acid components of fish oils and seaweeds, were also found in S. herbacea, S. komarvii, T. tetragonoides, A. capillaris and G. littoralis.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.10
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• pp.3772-3778
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• 2010

The leaders such as The Robert Foundation of the U.S., Social Firms U.K., EMES European Research Network worldwide are groping for the survival strategies of social enterprises and of their developmental methods with the utilization of social capital. Along with the way the world economy goes on, this study is first of all to empirically analyze how the diversity and strength of network as independent variables work with the studies of the survival of enterprises of Granovetter Mark, Burt Ronald, Coleman James, Peter Witt, Andreas Schroeter, Christin Merz, Helen Haugh, mainly concerned with the increase in employment, the increment in sales, delegation of authorization as dependent variables and secondly it is to present a theoretical possibility of optimizing the development of social enterprises. The object of this study consists of 25 companies recommended by experts out of the current national 295 social enterprises in 2009 through the analysis of sources of SPSS 12.0, appropriateness, reliability, interrelation, etc; besides, hypotheses are proved by multiple regression analysis. A result of the investigation indicates that there is the necessity of network in all the processes of the survival of enterprises, the growth in employment, the increase in sales, delegation of authorization; especially, it suggests that it is necessary to manage, maintain and develop primary factors relating to a variety of networks to improve sales, and relating to the intensity of network for the survival of corporations. At last, I think that this study could be a help to the strategies of utilizing social capital in order for many companies or nonprofit social organizations in Korea to develop into constant enterprises.