• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.440-440
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• 2012

Nanomaterials have emerged as new building blocks to construct light energy harvesting assemblies. Size dependent properties provide the basis for developing new and effective systems with semiconductor nanoparticles, quantized charging effects in metal nanoparticle or their combinations in 2 and 3 dimensions for expanding the possibility of developing new strategies for photovoltaic system. As top-down approach, we developed a simple and effective method for the large scale formation of self-assembled Cu(In,Ga)$Se_2$ (CIGS) nanostructures by ion beam irradiation. The compositional changes and morphological evolution were observed as a function of the irradiation time. As the ion irradiation time increased, the nano-dots were transformed into a nano-ridge structure due to the difference in the sputtering yields and diffusion rates of each element and the competition between sputtering and diffusion processes during irradiation. As bottom-up approach, we developed the growth of CIGS nanowires using thermal-chemical vapor deposition (CVD) method. Vapor-phase synthesis is probably the most extensively explored approach to the formation of 1D nanostructures such as whiskers, nanorods, and nanowires. However, unlike binary or ternary chalcogenides, the synthesis of quaternary CIGS nanostructures is challenging because of the difficulty in controlling the stoichiometry and phase structure. We introduced a method for synthesis of the single crystalline CIGS nanowires in the form of chalcopyrite using thermal-CVD without catalyst. It was confirmed that the CIGS nanowires are epitaxially grown on a sapphire substrate, having a length ranged from 3 to 100 micrometers and a diameter from 30 to 500 nm.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.43 no.2
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• pp.124-127
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• 1998

Since weedy rice problems have emerged with the recent advent of direct seeding cultivation in Korea, the establishment of effective control strategies for weedy rice is considered to be one of the urgent issues to be solved for widely practiced direct seeding rice cultivation. A three year experiment was conducted to investigate the occurrence pattern of weedy rice in four different rice cultivation practices: high ridged dry seeding, wet drill seeding, water seeding, and machine transplanting. The highest weedy rice occurrence of 11.0% was observed in high ridged dry seeding practice followed by 9.6% in wet drill seeding, 6.4% in water seeding practice, and 0.2% in machine transplanting practice, respectively. The same trend was observed when we examine the occurrence of contamination of panicle and rice grain by weedy rice. More contamination was observed in high ridged dry seeding than any other practices. It was also found that the possible emergence depths from the soil surface was deeper in both in ridged dry seeding and wet drill seeding practice (0-5 cm from the soil surface) than those in water seeding (0-4 cm), and machine transplanting practice (0-3 cm). The highest yield reduction of 19.5% was observed in high ridged dry seeding practice followed by 13.0% in wet drill seeding, 6.3% in water seeding practice. The reduction may have occurred to the competition between weedy rice and cultivated rice, These findings suggest that among the four cultural practices examined, the machine transplanting practice is the most effective method to control and reduce the weedy rice occurrence and weedy rice seed in soil.

• Information Systems Review
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• v.8 no.1
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• pp.159-179
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• 2006

With the advances in information technologies and the wide acceptance of IT outsourcing practices, subscription-based information & telecommunications services(ITS) become more available. Convergence and intensified industry competition have made it an imperative for the ITS providers to keep their current customers and acquire new customers at the same time. In this study, we developed a framework for effective customer management based on the factors influencing the post-purchase customer choice: stay with the present provider or switch to another one. Specifically, we classified the factors into four categories: Holding factors, Defect factors, Inducement factors, and Hurdle factors depending on the characteristics of the influence and direction of the influence. Based on the classification, we developed a post-purchase customer choice model for the subscription-based ITS providers. Then, we illustrated a possible application of the model in the context of the broadband Internet access service. The model could be used to increase the competitive advantage of service providers through the effective customer management in the subscription-based ITS market.

• Journal of Korean Elementary Science Education
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• v.21 no.1
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• pp.101-109
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• 2002

A cooperative teaming has been taken to consolidate the autonomous motivation of students and to develop a desirable attitude in a mutual cooperative atmosphere. Some studies on the reward effect showed that the reward after the evaluation, in the processes of cooperative learning, worked on students' learning motive directly, and the group reward was effective in learning attitude and the individual reward in academic achievement, respectively. Assuming that the group reward and the individual reward are organized and applied as a complex reward, the effects of rewards will appear, this study examined the effect of the complex reward on academic achievement and teaming attitude. For this study. 2 classes were randomly selected out of a elementary school in Gwangju and the teaming unit was based on chapter 4「The structure and function of plants」 in the 5-1 elementary Science textbook. This research has been done for 4 weeks after the students learned STAD for 8 weeks previously. The learning attitude was examined in pre and post tests, and the academic achievement was inspected twice at 2-week intervals after the pre test. The results were analysized by the SAS program In the case of academic achievement, both groups showed a significant improvement(p<.05). The experimental group showed no significant improvement in the first test, compared with the control group(p>.05), but after 4 weeks, it showed a significant improvement in the second test, compared with the control group(p<.05). From this result, it is identified that the reward should be done for a long time and the individual reward of the complex reward is successful in improving academic achievement. However, in the case of learning attitude, there was no meaningful difference in both groups(p>.05). But the control group showed a significant improvement, compared with the experimental group(p<.05). According to this result, it is indicated that the group reward only is more effective in improving learning attitude and complex reward can decrease the individual competition in experimental group.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.11 no.4
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• pp.46-56
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• 2008

This study examined the natural restoration of vegetation through monitoring of the development of a vegetation community from 2006 through 2007 after a forest fire. Approximately 5,000 $m^2$ in a forest near Topyeon-ri, Kangnae-myeon, Chungcheongbuk-do with Japanese red pine (Pinus densiflora) forest and its floor vegetation had been completely burned by a fire in April 2005. This area and another nearby Japanese red pine forest were selected as the experiment site and the control site, respectively. Vegetation survey was conducted at the experiment site and the control site. A seed bank experiment was carried out in the greenhouse to examine underground vegetation. Effective microorganism(EM) was applied to the seed bank experiment to estimate its effects on the direction of ecological succession. According to the results, a total of 36 plant species including shrub and herbaceous species were discovered in the experiment site. Quercus serrata, Lespedeza cyrtobotrya, and Castanea crenata, Rubus crataegifolius, Oplismenus undulatifolius, and Carex lanceolata were among the most abundant species. Biomass in the experiment site reached 2.4 times biomass than those in the control site, indicating the productivities of shrub and herbaceous layers are better in the experiment site. According to the result of the soil seed bank experiment of the experiment site, a total of 182 plants of 14 species were recorded. In addition, a total of 13 plants of 2 species were found from soil seed bank of the experiment site applied by EM. If EM is applied to the burned site, it will control the budding of herbaceous plants, creating the gap between herbaceous plants. This loss of competition is expected to help the restoration of trees in the burned area.

• Quality Improvement in Health Care
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• v.10 no.2
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• pp.144-153
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• 2003

1) Background: The hospitals of modem society, like any other business entities, have to constantly strive to secure their survival from aggressive changes and competition outside. In this unstable environment, effective leadership is one of the most effective strategies for securing organization's growth as well as stability. This study investigated types of leadership (transformational or transactional) that is dominant in medical record departments and compared it's effects on organizational commitment and job satisfaction of their organizational members by types. 2) Method: A questionnaire was developed and mailed to all medical record administrators working at general hospitals throughout the country except department directors (N=450). Of these, 150 useable questionnaires were returned and analyzed by t-test, multiple regression analysis using SPSS. 3) Results: The organizational commitment and job satisfaction were a little bit higher than moderate level, and that of leadership perceived by medical record administrators was also in moderate level throughout types. Significant characteristics (positively) related to organizational commitment and job satisfaction by univariate analysis were marital status (married), position (middle management) and both type of leadership. However transformational leadership was the only significant factor in leadership styles after considering all the factors related to organizational commitment and job satisfaction together by multivariate analysis. 4) Conclusion: The average organizational commitment and job satisfaction of medical record administrators was just in moderate level. Efforts should be made to increase them by improving leadership capacity of medical record directors, primarily by using transformational leadership approach.

• Journal of environmental and Sanitary engineering
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• v.12 no.3
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• pp.9-17
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• 1997

This research aims to remove nitrogen in the piggery wastewater by combined process with upflow anaerobic sludge blanket (UASB) and biofilm process. For the effective denitrification. anaerobic and anoxic reactors were connected to a reactor. The effluent of aerobix reactor was recycled equally with influent in the upper filter of anaerobic reactor for denitrification and outlet of UBF reactor was connected to the settling tank with $1.5{\;}{\ell}$ capacity and the settling sludge was repeatedly recycled to UASB zone. The organic loading rate of total reactor was operated from 0.4 to $3.1kgCOD/m^{3}/d$ and it was observed that the removal rate of TCOD was 80 to 95 percentage. Ammonia nitrogen was removed over 90 percentage in the less volumetric loading rate than $0.1{\;}kgN/m^{3}/d$. But because of non-limitation of organic materials, it was reduced to 70 percentage in the more volumetric loading rate than $0.6{\;}kgN/m^{3}/d$. But denitrification rate was observed 100 percentage in the all of loading rate. This is caused by the maintenance of optimum temperature, sufficient carbon source, and competition of electron acceptors. The results of COD mass balance at the $1.21{\;}kgCOD/m^{3}/d$ was observed with the 71.7% percentage of influent COD. It was revealed that the most part of organic materials was removed in the aerobic and the anaerobic reactor because 38.4 percentage was conversed into $CH_{4}$ gas and 11 percentage was removed in the aerobic reactor with cell synthesis and metabolism. Besides, 5.7% organics was used to denitrification reaction and 3.7% organics related to sulfate reduction.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.449-449
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• 2011

We reported the direct effect of intrinsic surface energy of dry adhesive material to the Van der Waals and capillary forces contributions of the total adhesion force in an artificial gecko-inspired adhesion system. To mimic the gecko foot we fabricated tilted nanohairy structures using both lithography and ion beam treatment. The nanohairy structures were replicated from Si wafer mold using UV curable polymeric materials. The control of nanohairs slanting angles was based on the uniform linear argon ion irradiation to the nanohairy polymeric surface. The surface energy was studied utilizing subsequent conventional oxygen ion treatment on the nanohairy structures which resulted in gradient surface energy. Our shear adhesion test results were found in good agreement with the accepted Van der Waals and capillary forces theory in the gecko adhesion system. Surface energy would give a direct impact to the effective Hamaker constant in Van der Waals force and the filling angle (${\varphi}$) of water meniscus in capillary force contributions of gecko inspired adhesion system. With the increasing surface energy, the effective Hamaker constant also increased but the filling angle decreased, resulting in a competition between the two forces. Using a simple mathematical model, we compared our experimental results to show the quantitative contributions of Van der Waals and capillary forces in a single adhesion system on both hydrophobic and hydrophilic surfaces. We found that the Van der Waals force contributes about 82.75% and 89.97% to the total adhesion force on hydrophilic and hydrophobic test surfaces, respectively, while the remaining contribution was occupied by capillary force. We also showed that it is possible to design ultrahigh dry adhesive with adhesion strength of more than 10 times higher than apparent gecko adhesion force by controlling the surface energy and the slanting angle induced-contact line of dry adhesive the materials.

• Journal of Korea Society of Industrial Information Systems
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• v.11 no.3
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• pp.20-33
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• 2006

Because of rapid expansion of third party logistics, fierce competition in the transportation industry, and the diversification and globalization of transportation channels, an effective transportation planning by means of multimodal transport is badly needed. Accordingly, this study aims to suggest an optimal transport algorithm for the multimodal transport in the international logistics. As a solution for this problem, first of all, we have applied a pruning algorithm to simplify it, suggesting a heuristic algorithm for constrained shortest path problem to find out a feasible area with an effective time range, which has been applied to the Label Setting Algorithm, consequently leading to multiple Pareto optimal solutions. Also, in order to test the efficiency of the algorithm for constrained shortest path problem, this paper has applied it to the actual transportation path from Busan port of Korea to Rotterdam port of Netherlands.

• Journal of Korea Society of Industrial Information Systems
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• v.12 no.4
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• pp.1-14
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• 2007

Upon the intensive competition, companies try to hold their current customers by investing more money and efforts on CRM activities. They provide various benefits for their customer to keep them and increase their loyalty. However many companies want to know how effective their CRM activities are. In this paper, we investigate the effectiveness of companies' different CRM activities on customer perception of different benefits as well as their loyalty. For this we categorize the benefits that companies provide for their customer into four different types of customer benefits such as social customer benefits, psychological customer benefits, economic customer benefits and customization benefits. We examine the effects of different customer benefits and how different the customer benefits vary depending on the types of industries and even on the involvement level, relationship types, and customer's acceptance level of risks. We found that the CRM activities had, in general, a positive effect on customers' perception and loyalty. However, companies had better selectively concentrate their CRM activities on the most effective ones considering the involvement level, relationship types, and customer's acceptance level of risks along with the industry where they belong.