• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.18 no.2
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• pp.101-108
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• 1982

In this paper the result of heat transfer analysis around the square heat source of interior solid by using the F. E. M is reported. Calculation for temperature distribution and each element was used by F. E. M. the solid is sub-divided into system of equal size triangular shape. These values of temperature distribution will valuable for design of jet engine and steam generator and the results gained are as follow; 1. Calculation by F. E. M is identified with the experiment. 2. Temperature distribution on the horizontal surface is $\theta$=0.698 in model 4 and the other hand $\theta$=0.401 in model 6 for X=16cm. In intermediates surface between heat source and bottom surface, the influence of L is more greater than that of height in the temperature difference. 3. Temperature distribution on the vertical surface for model 2 is resulted strong influence by K. In the case of Y=4cm is identified with $\theta$=0.0790 for K=7 and also $\theta$=0.0036 for K=0.3. In the difference of temperature distribution.

• Korean Business Review
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• v.21 no.2
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• pp.195-214
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• 2008

In 2004, in order to create core competences and major growth drivers for endogenous regional developments, the Korean government adopted the policies for establishing regional innovation systems, The main organization for the policies is the regional innovation council which is composed of diverse groups of scholars, professionals, and government officials. The regional innovation council of Kang-won Province consists of a couple of sub-divisions such as Operation Committee, Administration Office, Planning and Moderation Department, Strategic Industry Department, Culture and Tourism Industry Department, Regional Industry Department, and Regional Human Resource Development Department. The primary roles and jobs are planning, reviewing, evaluating and finalizing regional innovation policies. However, because of conflicts with local government, insufficient budget problems, organization structure problems, and decision making process problems, the regional innovation councils could not perform their original roles and functions. They could not adopt radical or non-traditional strategies. Although it's failure, a lot of people recognize the importance of regional innovation councils' roles and functions, I believe there would be another regional innovation councils coming continuously which would be take more important roles and have more power over budgeting problems. The purpose of this article is to identify the primary sources of strategies and organization structure problems of the previous regional innovation councils and to provide a couple of answers. In this paper, the author primarily analyze the problems of the Kang-won innovation council. A couple of answers to the desirable organization structures and the desirable roles of regional innovation councils will be presented for discussion.

• Journal of the Korean earth science society
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• v.23 no.3
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• pp.234-241
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• 2002

The purpose of the study is to investigate the applicability of portfolio assessment to ordinary elementary science classes, and the effects of a portrolio assessment on students' science achievement, inquiry ability, and science attiudes. Two schools were sampled from a metropolitan area, a city, and three schools from rural area in central Korea. Two fifth-grade classes were sampled from each school selected, and one class is assigned to experimental group and the other to control group, respectively. The total number of participants of the study are 475. Portfolio assessmest was administered to experimental group, and conventional teaching to control group for two and half month. Science achievement test, science inquiry ability test, and science attitudes test were administered as a pre- and post-test. Portfolio asseddment seems to be applecable to ordinary elementary science classroom. Statistically meaningful difference was not found in students' science achievemant by group, region, and sex. Students' inquiry ability and science attitudes showed statistically meaningful difference by region rather than group. Experimental group showed more positive scores on some sub-domains of science attitudes, such as perception on science education, and science career, interests in science activity, and criticism. In conclusion, portfolio assessment can be applicable to ordinary dldmentary science classrooms. The effects of portfolio assessment are at least the same as the traditional teaching on student science achievement, inquiry ability, and science attitudes.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.45 no.4
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• pp.13-20
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• 2008

This paper describes the design of low power 12bit Digital-to-Analog Converter(D/A Converter) using Pseudo-Segmentation method which shows the conversion rate of 80MHz and the power supply of 1.8V with 0.18um CMOS n-well 1-poly 6-metal process for advanced wireless communication system. Pseudo-segmentation method used in binary decoder consists of simple parallel buffer is employed for low power because of simpler configuration than that of thermometer decoder. Also, using deglitch circuit and swing reduced drivel reduces a switching noise. The measurement results of the proposed low power 12bit 80MHz CMOS D/A Converter shows SFDR is 66.01dBc at sampling frequency 80MHz, input frequency 1MHz and ENOB is 10.67bit. Integral nonlinearity(INL) / Differential nonlinearity(DNL) have been measured ${\pm}1.6LSB/{\pm}1.2LSB$. Glich energy is measured $49pV{\cdot}s$. Power dissipation is 46.8mW at 80MHz(Maximum sampling frequency) at a 1.8V power supply.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.8
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• pp.128-135
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• 2013

This paper presents a high dimming ratio Power-LED driver IC with high power which is capable of controlling LEDs. In order to accomplish a high dimming ratio LED driver, the preloading inductor current methodology is proposed for the power stage of the proposed method to achieve the fast transient response time during the Power-LED load switching. The information containing the current flowing on the LEDs can be utilized to predict the amount of the current on the inductor. The minimum LED current rising time of existing high dimming ratio Power-LED driver is limited by $3{\mu}s$, however that of the proposed high dimming ratio Power-LED driver is reduced about 1/10. The LED driver is implemented with 0.35um 60V BCDMOS 2-poly 4-metal process. The measurement results show that the proposed LED driver system features the minimum rising time as small as 240ns at the dimming frequency of 1KHz with a 12V of input voltage, nine white LEDs and 353mA of LED current. The LED rising time and power conversion efficiency of the chip are measured to be 240ns and 93.72%, respectively.

• Transactions of the Korean hydrogen and new energy society
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• v.21 no.6
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• pp.479-486
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• 2010

In order to confirm the effect of $HI_x$ solution on Bunsen reaction in Sulfur-Iodine thermochemical hydrogen production process, the reaction was investigated using $HI_x$ solution as a reactant. The phase separation characteristics of reaction with $HI_x$ solution were compared with the reaction using $I_2$ and $H_2O$ as reactants. Firstly, saturation points of $I_2$ in $HI_x$ solution at various temperatures were investigated to determine reaction conditions. With increasing temperature, the amounts of unreacted $I_2$ and $H_2O$ in $HI_x$ solution were increased, while impurities (HI in $H_2SO_4$ phase and $H_2SO_4$ in $HI_x$ phase) in each phase were decreased. The volumes of $H_2SO_4$ phase obtained from Bunsen reaction with $HI_x$ solution was relatively less than those obtained from the reaction with $I_2$ and $H_2O$. The difficulty of phase separation in Bunsen reaction using $HI_x$ solution may be due to the insufficient amount of $H_2O$ existed in $HI_x$ phase after reaction. Therefore, we concluded that the supplement amount of $H_2O$ should be calculated on the basis of the moles of HI and $H_2SO_4$ and added to the reaction system for good phase separation.

• Korean Journal of Construction Engineering and Management
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• v.17 no.3
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• pp.23-31
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• 2016

The domestic market of CM at Risk has not been activated yet. It was analyzed duo to the fact that construction owners didn't have confidence in CM at Risk, because of the concerns regarding CM firms reliability, service, specialty, system and feasibility. Therefore, this study analyzed the problems to find the reason for declines in orders through a business diagnosis based on the Business Model Canvas(BMC) and set up the direction of business model improvement with one on one expert interviews. Additionally, we suggested the sub-activities for the business model improvements of CM at Risk service that are divided into 9 building blocks. Through this method, we determined that we would need preceding innovation activities such as good communication with customers, reinforcement of subcontract and excellence in project operations to convert the successful practice and settlement of the CM business model based in BMC. It is expected that the business model suggested from this study would contribute to improvement of CM at Risk competition and the differentiation strategy when compared with other firms. Also, it would be used a basis data to develop CM at Risk business model in the future.

• Journal of the Korean School Mathematics Society
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• v.6 no.1
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• pp.1-17
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• 2003

In this paper, we study the methods of improving an ability of a creative solving mathematical problem belonging to an educational system which every province office of education has adopted for the mathematically talented students. Especially, we give an attention on a preferential reaction in teaching styles according to student's LQ., the relationship between student's LQ. and an ability of creative solving mathematical problems, and seeking for an appropriative teaching methods of the improvement ability of a creative solving problem. As results, we have the followings; 1. The group having excellent students who have a higher intelligential ability prefers inquiry learning which is composed of several sub-groups to a teacher-centered instruction. 2. The correlation coefficient between student's LQ. and an ability creative solving of mathematical is not high. 3. Although the contents and the model of thematic inquiry learning don't have a great influence on the divergent thinking (ex. fluency, flexibility, originality), they affect greatly the convergent thinking - a creative mathematical - problem solving ability. Accordingly, our results show that we should use a variety of mathematical teaching materials apart from our regular textbooks used in schools to improve a creative mathematical problem solving ability in the process of thematic inquiry learning. Also we can see that an inquiry learning which stimulates student's participation and discussion can be a desirable model in the thematic mathematical classroom activities.

• Journal of Energy Engineering
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• v.29 no.3
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• pp.64-73
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• 2020

This paper presented a methodology for calculating daily load curves per city by taking into account the charging/discharging location of electric vehicle. In other words, this is the daily load curve calculation algorithm by city, which takes into account the charging/discharging location of electric vehicles, so that the impact of loads generated by charging/discharging of electric vehicles on the power grid can be easily understood in certain cities. Specifically, in accordance with the PEVs share scenario, the PEVs discharge power was calculated to reflect both the characteristics of the arriving vehicle in the morning and the SMP plan after establishing a assumption that the electric vehicle arrived at work in the morning and the electric vehicle arrived at home in the afternoon for each of the charging/discharging locations, that is, work and home, of electric vehicles in the city. After calculating the daily load curve for each charging/discharging power type for the PEVs charging strategy, which takes into account both the characteristics of the vehicle arriving at home in the afternoon and the TOU fare system, it was analyzed by comparing the impact assessment on the grid by adding the existing load.

• Journal of Environmental Impact Assessment
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• v.26 no.5
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• pp.376-384
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• 2017

Bangladesh is a South Asian country with subtropical monsoonal climate between the intersection of the Indo-Himalayan and Indo-Chinese sub-regions, is known as biodiversity hotspot of the Asian region. The country has different types of forest like deciduous forest, evergreen forest, mixed forest, haor (wetlands) and mangrove forest. The natural beauty of the country is increased with the presence of so many rivers, longest sea beach of the world, green plants, critical hilly regions and green agricultural forest widely spread here and there. Sundarbans is the world largest mangrove forest and world natural heritage site declared by UNESCO in 1999 situated in Bangladesh and India. About 62 percent of this mangrove forest is situated in Bangladesh and there are so many plants and animals are found in this forest. To meet the increasing demand of the large population most of the natural ecosystem is now altered, deforestation rate is increased, natural habitat of the species is disturbed. Due to the imbalance of the climate and natural system many of the rare species of the world found this region is now endangered and some of the species are extinct. Directly or indirectly they are benefited from natural resources. At present time community, based ecotourism is also an important source of income for rural poor peoples. To protect the natural resources the government is now developed so many conservation acts and policy as well NGOs are also doing work for the conservation of ecosystem and biodiversity. At present transboundary pollutants and so many natural disasters also destruct the natural resources of Bangladesh.