• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.493-493
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• 2014

The manufacturing cost of thin-film photovoltics can potentially be lowered by minimizing the amount of a semiconductor material used to fabricate devices. Thin-film solar cells are typically only a few micrometers thick, whereas crystalline silicon (c-Si) wafer solar cells are $180{\sim}300\mu}m$ thick. As such, thin-film layers do not fully absorb incident light and their energy conversion efficiency is lower compared with that of c-Si wafer solar cells. Therefore, effective light trapping is required to realize commercially viable thin-film cells, particularly for indirect-band-gap semiconductors such as c-Si. An emerging method for light trapping in thin film solar cells is the use of metallic nanostructures that support surface plasmons. Plasmon-enhanced light absorption is shown to increase the cell photocurrent in many types of solar cells, specifically, in c-Si thin-film solar cells and in poly-Si thin film solar cell. By proper engineering of these structures, light can be concentrated and coupled into a thin semiconductor layer to increase light absorption. In many cases, silver (Ag) nanoparticles (NP) are formed either on the front surface or on the rear surface on the cells. In case of poly-Si thin film solar cells, Ag NPs are formed on the rear surface of the cells due to longer wavelengths are not perfectly absorbed in the active layer on the first path. In our cells, shorter wavelengths typically 300~500 nm are also not effectively absorbed. For this reason, a new concept of plasmonic nanostructure which is NPs formed both the front - and the rear - surface is worth testing. In this simulation Al NPs were located onto glass because Al has much lower parasitic absorption than other metal NPs. In case of Ag NP, it features parasitic absorption in the optical frequency range. On the other hand, Al NP, which is non-resonant metal NP, is characterized with a higher density of conduction electrons, resulting in highly negative dielectric permittivity. It makes them more suitable for the forward scattering configuration. In addition to this, Ag NP is located on the rear surface of the cell. Ag NPs showed good performance enhancement when they are located on the rear surface of our cells. In this simulation, Al NPs are located on glass and Ag NP is located on the rear Si surface. The structure for the simulation is shown in figure 1. Figure 2 shows FDTD-simulated absorption graphs of the proposed and reference structures. In the simulation, the front of the cell has Al NPs with 70 nm radius and 12.5% coverage; and the rear of the cell has Ag NPs with 157 nm in radius and 41.5% coverage. Such a structure shows better light absorption in 300~550 nm than that of the reference cell without any NPs and the structure with Ag NP on rear only. Therefore, it can be expected that enhanced light absorption of the structure with Al NP on front at 300~550 nm can contribute to the photocurrent enhancement.

• Journal of KIISE:Software and Applications
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• v.36 no.1
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• pp.21-29
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• 2009

An intelligent service robot is a robot that monitors its surroundings, and then provides a service to meet a user's goal. It is normally impossible for a robot to anticipate all the needs of its user and various situations in the surroundings ahead, and to prepare for all the necessary functions to cope with them. Therefore, it is required to support the self-growing capability by which robots can extend their functionality based on users' needs and external conditions. In this paper, as an enabler of the self-growing capability, we propose a method that allows a robot to select a component-composition pattern represented in an architectural form (called a sub-architecture), and to extend its functionality by obtaining a set of software components that are prescribed in the pattern. Sub-architecture is selected and instantiated not only based on the functionality required but also based on quality requirements of a user and the surrounding environment. To provide this method, we constructed a quality-attributes-in-use ontology and developed a brokering mechanism that matches quality requirements of users and surroundings against quality attributes of sub-architectures. The ontology provides the common vocabularies to represent quality requirements and attributes, and enables the semantically-based reasoning in matching and instantiating appropriate sub-architectures in supporting services to users. This ontology-based approach contributes to provide a great flexibility in extending robot functionality based on available software components, and to narrow the gap between users' Quality requirements and the Quality of the actual services provided by a robot.

• Journal of Environmental Impact Assessment
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• v.27 no.3
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• pp.267-278
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• 2018

With climate change and population growth, there are significant increases in water scarcity. There have been water security assessments to abate the gap between water demand and availability to support water resource management. However, most of the assessments are focusing on the water that flows through either on or below the land surface, failing to consider water that infiltrates and can be used by vegetation. This study presents water scarcity assessment accounting for Blue and Green water concept, and applied the method to Boryung region. Monthly streamflow, evapotranspiration, and soil moisture were estimated by SWAT modeling, and each of them was used to analyze Blue and Green water scarcity. Blue and Green water scarcity had different aspect, and the result indicated the time when water scarcity is more likely to happen. The water scarcity assessment framework presented in this paper provides novel assessment method integrating hydrologic and ecosystem aspects, thereby improving the understanding of how water resources should be managed.

• Korean Journal of Agricultural Science
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• v.20 no.1
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• pp.88-101
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• 1993

This study is aimed at evaluating the present management status of the rural special production area development projects and identifying managerial problems to propose new direction of the political countermeasures for the projects. In the con text of implementing the five year's economic developent plans for the past three decades, agricultural production and farm-household income have also been grown rapidly. However the income gap between rural and urbarn laborer, as an internal problem, has widened during the decades and the UR problems concerning free trade of agricultural products, as an external problems, are now agonizing the small-holder farm economy in Korea. The internal and external farm problems could be solved through improvement of agricultural structure and provision of off-farm jobs for farm household income increase. As a part of the off-farm income sources, the rural special production area development projects have propelled by the government throughout the country. The main problems to be solved for the successful implementation of the projects are as follows : 1. Present loan amount by the financial fund was estimated at 6-7% of the total installation costs required. To expand and implement the project successfully, enough financial credit support with favorable terms and conditions have to be considered by the government. 2. The operation patterns of the special production area development project should be recommended from the view point of cooperative and private operation to maximize farm household incomes including profits, marketing charges and dividens. 3. Improvement of the marketing channel of the products and marketing information through TV program and other mass communication should be implemented strongly to promote marketsales by the financial supports of the government. 4. In connection with the off-farm income increase, the population migrating to urban area in outside Chungnam province equivalent to 10-12 thousand persons with age of 20-49 years should be taken into account politically to be employed in the projects in the province. 5. Surplus farm labors should be created by means of improvement of agricultural structure including large farm management with farm mechanization and job opportunities have also to be provided in connection with the rural special production area development projects. The two imminent subjects are the prerequisites to increase off-farm incomes for the farmers living in Chungnam province. 6. Required credit supports for investment and operation costs of the projects should be taken actions by the government.

• Korean Journal of Social Welfare
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• v.56 no.1
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• pp.155-179
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• 2004

This study is about the effectiveness and activation strategies of vacational training programme for the disabled guided by the Ministry of Labour and the Korea Employment Promotion Agency for the Disabled(KEPAD). This research employed quantitative approach. The quantitative research used the samples of 853 disabled people who had finished vocational training programme during recent 3 years. In this research the effectiveness is categorized into two ; product effectiveness and employment effectiveness. Product effectiveness is influenced by the kind of train-center, train-area, train-length. The KEPAD, non-IT job area and train-period over 6 month are more effective. Employment effectiveness is significantly influenced by demo-sociological factor rather than disability factor. Especially the kind of train-center is very important to be employed for the disabled. This implicates that choice of train-center by the disabled and effective management of it by the public sector is very important in developing employment. Effective management, stated above, includes reengineering programmes and functions accountable to the need form the trainee, bridging the gap among train-centers in terms of performance, differentiation of financial support according to the product to save the public fund, encouraging one special programme in one train-center.

• 대한공업교육학회지
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• v.37 no.2
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• pp.1-19
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• 2012

In this study, to figure out the demands for learning, a survey was conducted on learning organization agents participating in learning organization project supported by public fund, through measuring their awareness level of the role and tasks drawn from the precedent study. This questionnaire was developed with four roles and twenty competencies drawn from the precedent study. After conducting the survey on over 200 small and medium corporations participated in learning organization project, the data was analyzed about the role and competency from 123 answer sheets collected. The results were as following First, the awareness of role importance was higher(4.36) than present level(3.73), and was important in order of innovator, operator, spreader, promoter. Second, in competitive importance of learning organization agents, the role of spreader was high, that of promoter was low. Third, in awareness level of learning organization agents, the demand level was generally high(4.1), but acquired level was generally low, so there was a wide gap between the demand level and acquired level. Forth, From the analysis result of those data about work competency of learning organization agents, learning organization promoter and learning leader, KMS operator ability and outcome were come out to be necessary, and next administrative ability about organization changes were come out to be necessary.

• Journal of architectural history
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• v.24 no.3
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• pp.43-56
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• 2015

Researches on the pit dwellings in the Joseon Dynasty era have been constantly conducted in the archeology field since the beginning of the 2000s. Most of the related researches in the past have been on the classification and chronological record of dwelling types in archeology, but architectural researches on the dwelling history that is connected from the prehistoric age to the Joseon Dynasty era are insufficient. There are no big differences between the excavated pit dwellings of the Joseon Dynasty era and those of the prehistoric age, so pit dwellings were considered to have been used as dwellings for common people until the Joseon dynasty era. This fact is confirmed by the frequency and density of pit dwellings. In this research, what space composition of the pit dwellings that are equipped with the Korean floor heating system is shown according to the plan types was examined and the development and transition process from pit dwellings to Folk houses were analyzed and their correlations with the Folk houses of the Joseon Dynasty era were examined. The Folk house form did not start with the form of the house on the ground but originate from the introduction of Ondol, the Korean floor heating system, to pit dwellings. As the Korean floor heating system is used, the room and kitchen space are composed in the pit dwelling, and the kitchen is expanded to the one that separates the fireplace for cooking to avoid heating that is unnecessary for the summer season. As the size of the dwelling was getting bigger, the division of the space is made by the pillars that support the interior space. Also, the dwelling is expanded into a single row house and a double row house according to the progress direction of Ondol. In other words, the pit dwellings in the Joseon Dynasty era develops with making up diverse floors through the combination and expansion of Ondol and kitchen according to the dweller's convenience and life style and surrounding environment. This research is significant in the sense that it helps understand the formation and development process of our traditional Folk houses and fills the gap between the pit dwellings, which have been dealt with inadequately, and traditional Folk houses in the Korean dwelling history.

• Journal of the Korean Chemical Society
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• v.57 no.1
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• pp.138-146
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• 2013

This study examined the characteristics of the National Assessment of Educational Achievement (NAEA) in Science according to gender. It investigated gender achievement differences in the science section of the 2010 NAEA, the ratio of gender difference in achievement, the ratio of correct answers within each content domain and behavioral domain, and the items which showed high differences between males and females. The results indicate first, that, for 9th graders, females outperformed males in academic achievement in science. Second, with respect to the ratio of correct answers, males outperformed females in the advanced and below basic level groups, but females outperformed males in intermediate level groups. Third, females outperformed males in knowledge and inquiry in the behavior domains, and in chemistry and biology in the content domains. Fourth, an analysis of the items showing the largest gender gap indicated that males outperformed females in interpreting data, while females outperformed males in the items concerned with daily life and items related to the memorization of rules. This research on gender differences in science will allow teachers to complement the weaknesses of students when they study science, and support improved instructional methods in science.

• Journal of Hydrogen and New Energy
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• v.26 no.5
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• pp.423-430
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• 2015

$Cu/ZnO/Al_2O_3$ catalysts for water gas shift (WGS) reaction were synthesized by co-precipitation method with the fixed molar ratio of Cu/Zn/Al precursors as 45/45/10. Copper and zinc precursor were added into sodium carbonate solution for precipitation and aged for 24h. During the aging period, aluminum precursor was added into the aging solution with different time gap from the precipitation starting point: 6h, 12h, and 18h. The resulting catalysts were characterized with SEM, XRD, BET surface measurement, $N_2O$ chemisorption, TPR, and $NH_3$-TPD analysis. The catalytic activity tests were carried out at a GHSV of $27,986h^{-1}$ and a temperature range of 200 to $400^{\circ}C$. The catalyst morphology and crystalline structures were not affected by aluminum precursor addition time. The Cu dispersion degree, surface area, and pore diameter depended on the aging time of Cu-Zn precipitate without the presence of $Al_2O_3$ precursor. Also, the interaction between the active substance and $Al_2O_3$ became more stronger as aging duration, with Al precursor presented in the solution, increased. Therefore, it was confirmed that aluminum precursor addition time affected the catalytic characteristics and their catalytic activities.

• Journal of Oriental Physiology
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• v.14 no.2 s.20
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• pp.229-237
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• 1999

Hwanhonsan has been used for curing tumor as a Oriental medicine without any experimental evidence to support the rational basis for their clinical use. This experiment was carried out to evaluate the possible therapeutic or antitumoral effects of Hwanhonsan extract against cancer, and to study some mechanisms responsible for its effect. Some kind of tumors were induced by the typical application of 3-methylcholanthrene(MCA) or by the implantation of malignant tumor cells such as leukemia cells(3LL cells) or sarcoma cells(S180 cells) and FasII cells. Treatment of the Hwanhonsan extract(daily 1 mg/mouse, i.p.) was continued for 7 days prior to tumor induction and after that the treatment was lasted for 20 hrs. Against squamous cell carcinoma induced by MCA, Hwanhonsan decreased. not only the frequency of tumor production but also the number and weight of tumors per tumor bearing mice(TBM). Hwanhonsan also significantly suppressed the development of 3LL cells and S180 cells implanted tumors by frequency and their size, and some developed tumors were regressed by the continuous treatment of Hwanhonsan extract into TBM. However, when tumor was induced by FsaII cells implantation, the growth of implanted cells in mice was delayed by the water extract of Hwanhonsan until 7 days and then rapid growth ensued. In vitro treatment of Hwanhonsan extract had no inhibitory effect on the tumor induced by some kind of cell lines such as A431 cells strain but it significantly inhibited the proliferation of 3LL cells, S180 cells. These results suggested that Hwanhonsan extract exhibited a significant prophylactic benefits against tumors and its antitumor activity was manifested depending on the type of tumor cells.