• Korean System Dynamics Review
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• v.2 no.2
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• pp.25-40
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• 2001

This paper describes the forecast of power plant construction in a competitive korean electricity market. In Korea, KEPCO (Korea Electric Power Corporation, fully controlled by government) was responsible for from the production of the electricity to the sale of electricity to customer. However, the generation part is separated from KEPCO and six generation companies were established for whole sale competition from April 1st, 2001. The generation companies consist of five fossil power companies and one nuclear power company in Korea at present time. Fossil power companies are scheduled to be sold to private companies including foreign investors. Nuclear power company is owned and controlled by government. The competition in generation market will start from 2003. ISO (Independence System Operator will purchase the electricity from the power exchange market. The market price is determined by the SMP(System Marginal Price) which is decided by the balance between demand and supply of electricity in power exchange market. Under this uncertain circumstance, the energy policy planners such as government are interested to the construction of the power plant in the future. These interests are accelerated due to the recent shortage of electricity supply in California. In the competitive market, investors are no longer interested in the investment for the capital intensive, long lead time generating technologies such as nuclear and coal plants. Large unclear and coal plants were no longer the top choices. Instead, investors in the competitive market are interested in smaller, more efficient, cheaper, cleaner technologies such as CCGT(Combined Cycle Gas Turbine). Electricity is treated as commodity in the competitive market. The investors behavior in the commodity market shows that the new investment decision is made when the market price exceeds the sum of capital cost and variable cost of the new facility and the existing facility utilization depends on the marginal cost of the facility. This investors behavior can be applied to the new investments for the power plant. Under these postulations, there is the potential for power plant construction to appear in waves causing alternating periods of over and under supply of electricity like commodity production or real estate production. A computer model was developed to sturdy the possibility that construction will appear in waves of boom and bust in Korean electricity market. This model was constructed using System Dynamics method pioneered by Forrester(MIT, 1961) and explained in recent text by Sternman (Business Dynamics, MIT, 2000) and the recent work by Andrew Ford(Energy Policy, 1999). This model was designed based on the Energy Policy results(Ford, 1999) with parameters for loads and resources in Korea. This Korea Market Model was developed and tested in a small scale project to demonstrate the usefulness of the System Dynamics approach. Korea electricity market is isolated and not allowed to import electricity from outsides. In this model, the base load such as unclear and large coal power plant are assumed to be user specified investment and only CCGT is selected for new investment by investors in the market. This model may be used to learn if government investment in new unclear plants could compensate for the unstable actions of private developers. This model can be used to test the policy focused on the role of unclear investments over time. This model also can be used to test whether the future power plant construction can meet the government targets for the mix of generating resources and to test whether to maintain stable price in the spot market.

• Journal of Digital Convergence
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• v.18 no.9
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• pp.423-431
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• 2020

The purpose of this study is to examine how the level of participation in dance classes affects the development of social skills and peer relationship. The results are as follows: First, in terms of social skill development and peer relationship based on demographic characteristics, competition-a sub-factor of peer relationship-was higher in male students. In terms of grade level, confidence-a sub-factor of peer relationship-was high in second year students. Second, in terms of the effect of dance class participation on social skill development, autonomy, achievement, and cooperation-sub-factors of social skill-were significantly influenced by the period of participation in dance classes. Participation frequency, on the other hand, was found to significantly impact accountability and activity. Such results indicate that longer dance class participation periods more significantly influences social skill development. Third, in terms of the influence of dance class participation in peer relationship, students who participated in dance classes longer experienced positive impacts regarding sub-factors of peer relationship. Longer participation periods were correlated with lower hostilities. That is, longer participation period and time, as well as, higher participation frequency, have impact on peer relationship.

• Survey Research
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• v.6 no.2
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• pp.75-101
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• 2005

This study introduces and analyzes the data from Directory of Korean NGOs, which was published in 1997 and again in 200, to conduct a quantitative research on the growth of civic organization in South Korea. This paper focus on the information on membership size and founding year which are essential indicators for the growth of organizations. Missing rates on those two indicators are checked to evaluate the quality of data. We examine the changes in membership size between the two time periods, 1996 and 1999. It shows that there is a considerable decrease in the membership size for civic and advocary organizations that are oriented to national issues. It suggests the competition among the organizations over limited resources, which is consistent with an assumption of ecological theory of organization on non-linear growth pattern. Using founding year data from 1945 to 1996, we estimate pseudo growth curves of civic organizations based on logistic growth curve model to discuss different growth patterns of organizations across areas of activities.

• Archives of design research
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• v.18 no.1 s.59
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• pp.253-262
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• 2005

In suddenly changing multimedia periods, department store not only plays the role of local culture centre but also meets keen competition in working out marketing strategies, especially in the field of differentiating Promotion Surroundings Image, in order to cope with the varied consumers' pattern according to customers' pursuing new lifestyle. In particular, cosmetic stores located in the first floor of the department store have high sales rate in spite of its comparative small area, because cosmetic stores have been much essential to women's daily life who are very strong for desiring the Beauty and also in them men's buying trends have been upwards speedily. The color and P.P.(Point of Sale Presentation) of the cosmetic store design are preferred after the quality and the price of the goods, staff's services by this survey of female clients' attitude to buy cosmetics at department store in Seoul. So that cosmetic companies seem to be needed to offer the differentiated color code in each brand and display the goods' P.P.(Point of Sale Presentation) intensively to promote the sales effectively. This thesis aims at suggesting the way how cosmetic firms get and enhance their goods' competitiveness when they develop their visual merchandising strategy by considering each brand's attribute and customers' life style by age, preference factors for buying the goods through showing high qualified sonics in their differentiated displayed stores.

• Animal cells and systems
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• v.13 no.1
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• pp.71-78
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• 2009

To clarify the reproductive function of vibration signals in Hynobius, which has externally fertilized eggs, we quantitatively analyzed the body and tail undulations of male Korean salamanders (Hynobius leechii) in sixteen mating events. One large and one small male, and one female were used in each mating event. We analyzed behaviors recorded over a total of 3 hrs for each mating event; 2 hrs before and 1 hr after female's oviposition. Males touched females using their snouts or body trunk throughout the entire mating periods, but females touched males increasingly more after approximately 1 hr before oviposition. Males conducted body undulations more than 50 times per 10 minutes at a mean frequency of 0.64 Hz. Large males conducted more body undulations than small males, particularly on the tree twig where females attached their egg sacs. Males responded to other males' body undulation throughout the mating period by orienting their head towards, approaching, and touching the undulating male. Females only responded for about 10-20 min before ovipositing, and most responses were directed to the large male's body undulation. Males conducted tail undulations 3.0 times per 10 min at a mean frequency of 1.7 Hz and most tail undulations occurred after one male bit the other male. These results suggest that body undulations function in both male-female and male-male interactions, while tail undulations mainly functions in male-male competition. Also, male H. leechii appear to actively attract females, while females respond to the males only at times close to oviposition.

• Journal of Ecology and Environment
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• v.44 no.2
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• pp.62-71
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• 2020

Understanding vegetation structure and the relationship with environmental factors has been crucial for restoration and conservation of riparian zones. In this study, we conducted field survey in a riparian zone of Namhan River in South Korea both before and after flooding in order to understand temporal and spatial variations of riparian vegetation. There were significant temporal and spatial variations in species composition, and distribution patterns of vegetation were different along a gradient of elevation above the water level. At low elevation, Zizania latifolia was dominant throughout the field survey periods, and Bidens frondosa began to grow late and dominated both in post-flooding 1 and 2. Prior to flooding, Scirpus radicans and Polygonum thunbergii were widely distributed at middle elevation, while Artemisia vulgaris, Phragmites australis, and Miscanthus sacchariflorus were dominant at high elevation. After flooding, P. thunbergii was dominant at middle elevation with most other species decreasing, and more invasive or pioneer plants, including Artemisia princeps, H. scandens, and Sicyos angulatus, were observed at high elevation. Species composition and distribution patterns were homogeneous at low elevation, whereas dynamic variations of vegetation were observed both temporally and spatially at higher elevations. Elevation and distance from the water front were the most principal factors governing vegetation structure. Furthermore, soil physicochemical properties were also found to determine species composition and distribution patterns. These results indicate that vegetation structure in the riparian zones is formed by the combined effects of hydrological regime and soil physicochemical properties, inherent characteristics of species, and interspecific competition. Understanding of temporal and spatial variations of riparian vegetation may provide useful insights into ecological restoration and conservation of the vegetation within the riparian zones.

• The Journal of Korean Medicine
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• v.35 no.1
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• pp.145-156
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• 2014

Objectives: Korean medicine hospitals, since they first emerged in the early 1970s, have rapidly become a new member of the hospital population. As it was a new organizational frame for traditional medicine, we tried to analyze the changes of Korean medicine hospitals coping with institutional environment and their relative positioning in the whole health care sector. Methods: On the basis of Scott and his colleagues' identification of the three components of institutional environments, changes in organizational logics, actors, and governance of Korean medicine hospitals during the period from 1971 to 2010 were analyzed. Results: First, Similar to previous literature on institutional eras of Korean health sector, three distinct periods were characterized: the foundation of Korean medicine hospitals to consolidate the legal status(1971~1986), a rapid increase of entrepreneurial hospitals through cultural-cognitive legitimacy(1987~2001), and the reinforcement of specialization and competition(2002~present). Conclusions: Results suggested that: (1) changes in institutional environments hada heavy impact on structural and behavioral changes among Korean medicine hospitals, but the pace was slower than that of western medicine hospitals. (2) In structure, Korean medicine hospitals have positioned themselves as unofficial long-term care hospitals, focusing on chronic diseases(e.g. cerebrovascular disease). Our study demonstrated that organizational theories can provide useful framework for the analysis of Korean medicine and related policies. Indeed, one of the most important implications of this study is that understanding changes in institutional environments is important to understand the process of how members of the health care sector live, grow, change, decline and survive.

• Journal of the Korean Society of Clothing and Textiles
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• v.16 no.3 s.43
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• pp.233-242
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• 1992

This study primarily concentrates on the Fashion Style of the New Generation which has come into being in 1980 with reference to the contents of the newspaper and magazine in 1950's. . The New Generation has undergone the social and cultural change under the effect of mass communication, mass consumption brought by the economic development, sports boom promoted during the period of Asian Games and Seoul Olympic Games and the adoption of the policy for the autonomous school uniform. In the process of the social and cultural change, they have the common peculiarity such as sensitivity, anthoritarianism and polarity and they have taken an important part in the development of the 'Young Fashion' The characteristics of their fashion styles are divided into three periods as follows; 1. The rising period (1980-1982): The most important pecuriality of the first step can be sum up to the following point. The free fashion style replaced the formal one such as T-shirt or casual wear comes into as a everyday dress. Moreover, many people become interested in the New Fashion which is gradually diversified and high-qualified. As a natural consequence, the lively interest of the people has brought into the appearance and competition of the New Brand in fashion industry 2. The growing period (1983-1986): Mannish Look, so-called 'New Fashion' gained the summit of the fashion and change over conservatively. However, 'Mannish Look' have great effect on the Fashion Style until now on. Specially in Korea, 'Punk Style'and 'Androgynous Look' can be an example among many. 3. The diversifying period (1987-1989): The Fashion Style has developed variously even though the Reactionism takes the lead as the main current of the Korean Fashion. Moreover, it is noticeable that man comes into the stage as a new fashion group and the fashion market begins to dear in various lines of goods with moderate and low prices. These various aspects can be regarded as diversification in the Fashion Style as the needs in the times and society.

• Journal of The Korean Society of Agricultural Engineers
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• v.60 no.5
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• pp.55-67
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• 2018

The objectives of this study were to monitor organic farming upland compared with conventional upland field and to evaluate nutrient loads reduction of surface cover effect with long-term historical climate data. APEX(Agricultural Policy Environmental eXtender) model was validated with experimental data and used for assessing surface cover scenarios for 30-year simulation periods. The validated values of RMSE(Root Mean Square Error), RMAE(Root Mean Absolute Error), $R^2$ and E(Nash-Sutcliffe efficiency) for runoff were 1.17-1.37 mm/day, 0.28-0.45 mm/day, 0.88-0.90 and 0.82-0.94 in two treatments, respectively. Those for water quality (nitrogen) were 0.05-0.16 kg/ha, 0.52-0.75 kg/ha, 0.67-0.72 and 0.32-0.70 in two treatments, respectively, and therefore the validated model showed good agreement with the observed runoff and nitrogen load for the study period. When decreasing the surface cover rate of organic farming field to 75%, 50%, 25%, and 0% (conventional field), average annual runoff increased by 7%, 15%, 23% and 31%, respectively. Under same condition of decreasing the surface cover rate, average annual nitrogen loads increased by 1.4 times, 1.7 times, 2.0 times, and 2.3 times compared with organic farming field, respectively. This study showed that it is possible to present an appropriate surface cover ratio to maintain conventional production and minimize nonpoint sources pollution for organic farming system, although long-term monitoring is needed to determine its effects on environmental concerns, crop competition, and other uncertainty.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.54 no.4
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• pp.434-444
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• 2021

The decrease in fatness of the Pacific oyster Crassostrea gigas, which consequently results in decrease in the profit of aquaculture industry, has become a source of serious concern in southeast coast of Korea. The ratio of flesh (edible portion) to total oyster weight, commonly called edible portion yield ("suyul" in Korean), have been used as a fatness index for the healthy and valuable state of oyster from the early stage of oyster farming in Korea. More than 360 data sets were collected from early culturing periods (in the 1970s) to the present from approximately 15 published literatures to evaluate the long-term fatness trend of oyster, reared particularly in submerged longline culturing system in Gyeongsangnam-do province. Slight decrease in oyster fatness during the 1970s to 1990s was detected in Tongyeong and Geoje Bays; however, from the 1990s to the present, clear decreasing trends were observed with a decrease of 0.04-0.08% year^-1, especially during harvest season. Oyster mass production per unit area almost doubled within a short period in the early 2000s; however, changes in coastal environment factors inhibited the fattening of shellfish from the mid 1990s. These results indicate that the severe competition in feeding and low biological production in water column might be some convincing reasons for the decrease in fatness of oyster from the 1990s, in Tongyeong and Geoje Bays, Korea.