• Journal of the Institute of Electronics Engineers of Korea CI
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• v.39 no.1
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• pp.14-22
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• 2002

We propose the fuzzy BCMP queueing network model for the performance evaluation of distributed processing system with the ambiguous arrival rates of job, service requirements, and service rates of server by the network environments. This model is classified as the open and closed type whether or not the network accepts jobs from the system outside. We derived the measures for system performances such as the job average spending time, average job number in the system and server utilizations using fuzzy mean value analysis which can process the fuzzy factors for both types. Computer simulation was performed for verifying the effectiveness of derived equations of performance evaluation. The fuzzy BCMP queueing network model was evaluated according to the fuzzy arrival rates of job, the number of clients, and the fuzzy service requirements of job for each the open and closed type. The results were agreed with the predicted performance evaluations of the system.

• Journal of Wetlands Research
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• v.15 no.1
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• pp.51-58
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• 2013

In this study, the hydraulic experiments were conducted for the dredging efficiency of the cutter head type, which includes the open type and the close type cutter head. The dredging experimental instrument was installed in the large water tank which has the dimension of $4.9m(L){\times}2.2m(W){\times}1.5m(H)$. The dredging experiments were performed for the various conditions of dredging depth, rotating speed, and suction speed of the cutter head. As the results, the dredging efficiency of the close-type cutter head is much higher than that of the open-type cutter head. The dredging efficiency of the same cutter head type was mainly influenced by the rotating speed of cutter head. Also the adequate suction speed of the cutter head is needed for more effective dredging.

• Fire Science and Engineering
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• v.33 no.2
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• pp.79-84
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• 2019

The use of emergency escape breathing devices (EEBD) is strongly required to protect against toxic gas or flooding caused by ship fires or accidents. Recently developed domestic EEBD products only satisfy the basic performance requirements, but no wear fit and activity performance evaluation has been done for real usage. In this study, the global level test requirements for wear comfort and activity of EEBDs were developed and the open and closed type of domestic EEBD products were evaluated. Poor visibility, longer wear time, breathing resistance, and hose obstruction in an open type and canister obstruction, weight unbalance, and an invisible black breathing bag in the closed type EEBD were estimated to be the main problems that need to be improved.

• Journal of dental hygiene science
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• v.11 no.5
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• pp.431-436
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• 2011

The aim of this study was to compare the effects of the short-term use of the desensitizing dentifrices marketed in Korea in vitro. Fifty human dentine specimens were wet ground with silicone carbide paper and etched with 6% citric acid for 90 seconds to allow complete opening of the dentinal tubule. Ten specimens from each group were brushed for 50 and 150 strokes with a V8 Cross Brushing Machine(Sabri Co., U. S. A). All the specimens were evaluated by SEM(${\times}3000$). The degree of occlusion of the dentinal tubules was quantified using an image analyzer. The results were analyzed by one-way ANOVA and Tukey's multiple comparisons using Window SPSS. The dentifrices containing nano-carbonate apatite, potassium nitrate and hydroxyapatite showed significantly higher occlusion effects than the other dentifrices after toothbrushing for 50 strokes(p<0.05). The Sensodyne freshmint$^{(R)}$dentifrice showed 34% fewer open tubular areas compared with the Sensodyne original$^{(R)}$dentifrice for 50 strokes. According to the short-term use of desensitizing dentifrices, the dentifrices containing nano-carbonate apatite, potassium nitrate and hydroxyapatite were most effective in occluding the dentinal tubules.

• KDI Journal of Economic Policy
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• v.34 no.1
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• pp.87-133
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• 2012

This paper consists of two parts. The first part introduces a simple endogenous growth model. It is based on Romer(1990), but extends the original model by incorporating individual workers skill heterogeneity. Based on the heterogeneity, the model has a labor allocation mechanism between skilled (research) and unskilled (production) sectors. Different from Romer(1990), the labor allocation is determined by both demand and supply conditions of the economy. The endogenous growth model presented in this paper shows how the shape of the distribution of human capital affects on the labor allocation, hence on the employment structure, wage profile and economic growth. The model can be extended to an open economy. With the heterogeneity, the extended model explains distributional effect as well as growth effect of the economic openness. The second part provides empirical evidence in support of the extension part of the model presented in the first part. Based on the endogenous growth framework as proposed by Romer(1990) and Rivera-Batiz and Romer(1991), the model explains how economic openness affects labor allocation between skilled and unskilled sectors. According to the model, economic openness can affect labor allocation through two channels; knowledge spillover and specialization. First, the openness promotes knowledge spillover and hence increases the productivity of workers in the skilled sectors. This makes the economy employs more workers in the skilled sector. On the other hand, the openness causes global specialization which leads more employment in the skilled sector for the developed countries but at the same time, leads less employment in the skilled sector for the developing countries since the developing countries have comparative advantages in the unskilled sector. The empirical results obtained using cross country panel data in this paper support these two effects of knowledge spillover and specialization.

• Journal of the Korean School Mathematics Society
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• v.10 no.3
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• pp.303-322
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• 2007

This study is to investigate student's processes of problem solving using open-ended Geometric problems to understand student's thinking and behavior. One 8th grader participated in performing her learning in 5 lessons for June in 2006. The result of the study was documented according to Polya's four problem solving stages as follows: First, the student tended to neglect the stage of "understanding" a problem in the beginning. However, the student was observed to make it simplify and relate to what she had teamed previously Second, "devising a plan" was not simply done. She attempted to solve the open-ended problems with more various ways and became to have the metacognitive knowledge, leading her to think back and correct her errors of solving a problem. Third, in process of "carrying out" the plan she controled her solving a problem to become a better solver based on failure of solving a problem. Fourth, she recognized the necessity of "looking back" stage through the open ended problems which led her to apply and generalize mathematical problems to the real life. In conclusion, it was found that the student enjoyed her solving with enthusiasm, building mathematical belief systems with challenging spirit and developing mathematical power.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.10a
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• pp.827-830
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• 2009

Feature of current IPTV services is that the IPTV Provider buys the rights of contents from contents author and provides consumers monopolistically with those. In this environment, IPTV is indistinguishable from the way of existing broadcasting services. To shift away from this structure, it is necessary to guarantee the common user's participation and provide the Open IPTV services for customers to be allowed to have be defined for more opportunities to select the contents. However, there are some problems to conduct Open IPTV service due to a variety of rights protection solutions designed by previous digital broadcast providers. Therefore, a new framework is needed to overall Open IPTV environment. This paper provides the design can packaging contents authoring and consuming tool for IPTV application service based on Open IPTV.

• Journal of the Society of Naval Architects of Korea
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• v.32 no.4
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• pp.9-18
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• 1995

The use of CAD/CAM systems is growing fast in the shipbuilding industry. To develope a geometric modeler, the existing CAD/CAM systems have been analysed. Because existing systems have closed architectures, it is not easy to investigate the internal structures. However, new trends in the software engineering, open architectured systems, pose some possibility to develope the geometric modeler. Several geometric modelers are analysed to extract component functions and modules. ACIS of the Spatial Technology, AIS of the CAM-I consortium, the STEP part for the geometry and topology, CAD*I of the ESPRIT project, and domestic modelers are investigated. Based on this analysis, a reference model which shows the framework of the modeler is proposed. With the data structure supporting non-manifold topologies, the reference model can be used to encourage a cooperative development program.

• Ocean and Polar Research
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• v.25 no.2
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• pp.183-200
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• 2003

In order to assess the ecological changes induced by organic pollutants of the Shihwa Lake, BPI (Benthic Pollution Index) based on the benthic faunal community was employed. It was modified from Infaunal Trophic Index (ITI), and recommended as a pollution detecting method for the environmental assessment. The BPI values were calculated from the benthos data, which were collected for three terms: in 1980, before the Shihwa Lake was built up; in 1994-1997, which the Shihwa Lake was completely isolated from the outer seawater; in 1997-1999, after inflow of the outer seawater. Since the Shihwa Dike was constructed in February 1994, the pollution intensity of the lake had been increased from the narrow and inner part of the former Gyeonggi Bay and spread fast along the coast line of the Shihwa Lake. Then, in 1996 it showed the very high BPI levels all around the Lake. This serious polluted condition had been lasted till 1997, when the inflow of the seawater was begun. In 1998, from the nearest part of the Shihwa Gate, the BPI levels gradually became low in most area of the Lake, except its inner and narrow part. These greatly lowered BPI levels mean that the seawater inflow could be assumed to affect positively in the lake. Furthermore, BPI gave the same results from the other environmental assessment based on the abundance and the species richness of macrobenthic community. It shows that BPI could be useful as an effective method to assess the marine environment and evaluate the status of environmental conditions.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.1
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• pp.274-281
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• 2015

Firms are becoming increasingly dependent on external resources for a competitive advantage in environmental turbulence, the requisite speed of organizational change. Therefore, they focused on an 'Open Innovation'. This study examined the relationships among entrepreneurial orientation, learning orientation, open innovation, and new product development. The results provide broad support for the following: (1) entrepreneurial orientation and learning orientation strongly drive open innovation, (2) open innovation has a significant effect on new product development, and (3) learning orientation has a positive effect on open innovation and new product development. These results provide unique insight into how firms develop new product through open innovation. This study also addresses the implications of these results and the possible limitations of the research.