• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.373-378
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• 2003

Korea's overseas construction industry has been rather depressed by the weakened profitability as well as the sharp decrease of the market shares due to the lack of international competitiveness and the declined international market following the outbreak of Iraq war. There exist a lot of various risks in performing the overseas construction, and especially EPC projects, which entail complicated process from different parts, also require a sophisticated procurement and management skill. Subsequently, to survive in the competitive international market, we need to establish strategies to select potentially profitable projects at the initial stage of bidding process and to mitigate the high degree of risk exposures through contract negotiation and its adjustment. This research provides the profitability evaluation bases, with which overseas construction participants can forecast and analyze the risk more systematically, by eliciting profit-influencing factors from real overseas construction projects and structuring their cause-and-effect relationships. The profitability causal hierarchy structure describes the profitability factors' hierarchy in details and their interrelationships. It also enables us to find out critical factors directly related to profitability aggravation through a qualitative analysis. Ultimately, with this hierarchy structure as the base, the research will suggest how to develop the quantitative profitability forecasting model.

• Journal of the Korea Organic Resources Recycling Association
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• v.23 no.3
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• pp.33-41
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• 2015

An alternative was investigated to maximize the treatment efficiency of wastewater treatment plant without large scale expansion. 79% of detention time was required for enough nitrogen control. As aeration time was extended, nitrification was processed, but opposite trend was seen in phosphorus. High concentration of $NO_3-N$ interrupted PAOs activity not to absorb phosphorus. An alternative was devised for selective use of anaerobic or anoxic zone. Trisection was suggested for alternative use of center room. The result was relatively successful. The concentration of phosphorus was reduced with reduction of nitrogen. Extended anaerobic condition seemed to stimulate denitrification. Valve connection of internal return from aeration tank will make it possible to use middle room alternatively. This method will be a good alternative for seasonal variation of water temperature.

• Journal of the Korean Society of Costume
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• v.41
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• pp.185-206
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• 1998

The purpose of this study was to improve productivity for maximum effects with the present equipments and staff. This study compared and analyzed the mea-sured time by using stop watch method and MTM, which was the new measuring method. The flow and results of this study were as follows: 1. This study investigated the theoretical background the efficiency for production management, and the way of productivity improvement through documentary research. 2. Setting up the standard flow on the experi-mental company production, making out a process chart and measuring the actual working hour. 3. The study measured the allowance time applying work sampling. 4. Each process of the movement analysis was filmed by video to use basic data. 5. MTM analysis was taken by choosing 10 processes from front bodice according to the basic movement of MTM. Through the results, this study exclude unneccesary movements and suggest a method for working ways. 6. Using the actual working hour measured by a stop watch calculated the pitch time and presumed the amount of daily productivity. 7. The result of the work sampling came out as 38% of allowance rate. It was 13% higher than the standard amount of woman's jacket allowance rate, which was 25%. The most influencing factor was work discussion. That was because there were commuication problem of the work way between the operator and leader. More adequate use of flow table and level passing table was needed. There were the problems that inappropriate places and sizes made the distance of movements longer and often needed more adjustment of works and surroundings. To prevent breakdowns equipments check ups were necessary before works. 8. The results of MTM analysis were as follow : the time was reduced 40% than the actual measured time by a stop watch. This was because the leveling of the operator was included in the real calculation. Also, leveling was included in MTM analysis and all the conditions were standarized. Therefore MTM method was a scientidic measuring way of establishing the standard time. The presented method of this study, suggested an ideal method eliminating unneccesary motions, and presented standardization of works. Improvement of working methods, work condition and simplifying motions in each 10 processes reduced the working time from total 656 seconds to 301 seconds. 9. The way and time of working was linked together in the MTM analysis methods. Thus data from MTM help suggest not only establishing standard time but also establishing stan-dard work. Plus it includes various ability for improvements of working ways. So it is an objective method which can be widely used in other work studies. 10. The function of a time study is to determine the amount of work produced with a given method. The work rate is used to establish the cost of labor. The wage of worker must be calculated per unit time which is deter-mined before the time study is made. This study tried to introduce the incentive rule for deciding wages according to the standard time by MTM method.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.10
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• pp.1081-1089
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• 2005

In order to examine the application feasibility of Orimulsion fuel in a commercial boiler using heavy fuel oil, a numerical and experimental research efforts have been made especially to figure out the fundamental combustion characteristics of this fuel in a small-scale boiler. One of the notable combustion features of Orimulsion fuel is the delayed appearance of flame location with the flame shape of rather broad distribution, which is found experimentally and confirmed by numerical calculation. This kind of flame characteristics is considered due to the high moisture content included inherently in the process of Orimulsion manufacture together with micro-explosion by the existence of fine water droplets. In order to investigate the effect on the combustion characteristics of Orimulsion, a series of parametric investigation have been made in terms of important design and operational variables such as injected amount of fuel, types of atomization fluid, and phonemenological radiation model employed in the calculation, etc. The delayed feature of peak flame can be alleviated by the adjustment of the flow rate of injected fuel and the generating features of CO, $SO_2$ and NO gases are also evaluated in the boiler. When the steam injection as atomizing fluid is used, the combustion process is stabilized with the reduced region of high flame temperature. In general, the calculation results are physically acceptable and consistent but some refinements of phenomenological models are necessary for the better resolution of pollutant formation. From the results of this small-scale Orimulsion boiler, it is believed that a number of useful information are obtained with the working computer program for the near future application of Orimulsion fuel to a conventional boiler.

• Journal of the Korean Institute of Intelligent Systems
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• v.10 no.5
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• pp.487-496
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• 2000

In this paper, the Multi-FNN(Fuzzy-Neural Networks) model is identified and optimized using HCM(Hard C-Means) clustering method and genetic algorithms. The proposed Multi-FNN is based on Yamakawa's FNN and uses simplified inference as fuzzy inference method and error back propagation algorithm as learning rules. We use a HCM clustering and Genetic Algorithms(GAs) to identify both the structure and the parameters of a Multi-FNN model. Here, HCM clustering method, which is carried out for the process data preprocessing of system modeling, is utilized to determine the structure of Multi-FNN according to the divisions of input-output space using I/O process data. Also, the parameters of Multi-FNN model such as apexes of membership function, learning rates and momentum coefficients are adjusted using genetic algorithms. A aggregate performance index with a weighting factor is used to achieve a sound balance between approximation and generalization abilities of the model. The aggregate performance index stands for an aggregate objective function with a weighting factor to consider a mutual balance and dependency between approximation and predictive abilities. According to the selection and adjustment of a weighting factor of this aggregate abjective function which depends on the number of data and a certain degree of nonlinearity, we show that it is available and effective to design an optimal Multi-FNN model. To evaluate the performance of the proposed model, we use the time series data for gas furnace and the numerical data of nonlinear function.

• Journal of the Korean earth science society
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• v.26 no.1
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• pp.9-29
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• 2005

By analyzing and integrating established geological field study instances, this study offered a new geological field excursion teaching model with several steps: unifying question raising. excursion generalization. intensive field direction, searching, primary conclusion, re-searching, group discussion. adjustment, and excursion summarizing. Then by Qualitatively assaying the responses which students showed after applying this teaching model, a concrete teaching plan was sought for earth science teachers who were planning to begin geological field excursion classes. Students evaluated very highly on the unifying question and excursion generalization because these items provided a sense of direction and an overall theme for geological excursion in advance. Also. since the students had little to none geological knowledge and field excursion experience, the intensive field direction gave them a lot of help with their field excursion activities. Students thought that coming up with a primary conclusion based on the summary of what they had observed in their activities was original. and highly valued the process of sharing different opinions in group discussions and drawing out a final conclusion. Teachers should help students develop a friendly atmosphere, by organizing group activities and continuously feedlng them with uniting questions and excursion generalization within the groups. Also they should prepare enough contents for intensive field direction and ways to get their points across. In the process, they should arrange beforehand detailed instructions for every outcome, with the intention of solving the question. Furthermore. teachers should follow carefully how conclusions are drawn. instruct students not to reach conclusions based on mere assumptions, and be aware of misconceptions students have toward geological phenomenon in advance, so that the discussion can be lead in the right direction.

• Journal of Adhesion and Interface
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• v.21 no.3
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• pp.81-85
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• 2020

Shaving dust is a collagen fiber that is the leather waste occurred for thickness adjustment during the natural leather manufacturing process, and causes problems such as an environmental contamination because of a chromium (Cr) contained when it comes to reclaiming process. Various studies applying the shaving dust are currently being conducted in many countries across the world with an initiative by the EU. Of those applications, the bonded leather is being highlighted as a substitute for natural leather. Since the bonded leather, however, uses latex as a binder, accordingly it entails a high weight and a poor ventilation, which are deemed as disadvantages due to its dense internal tissues compared to other synthetic leathers. To address such disadvantages, this study employed the thermally expandable micro sphere to improve its air permeability and light weight by alleviating the internal structure. This is a study on the manufacturing of light bonded leather using the shaving dusts. In the study, the shaving dusts were forced to foam under 100~120℃ considering the heat resistance of collagen fiber after applying the thermally expandable micro sphere, and then the tendency was analyzed. In the analysis results, the most excellent foaming rate was exhibited when the shaving dusts were treated under 120℃ for 8 minutes and the variation of internal structure according to a foaming was observed through SEM analysis for the cross-section of the bonded leather.

• Journal of the Korean School Mathematics Society
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• v.17 no.4
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• pp.717-746
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• 2014

The study aimed to explore how to improve mathematical thinking through metacognitive learning by stressing metacognitive abilities as a core strategy to increase mathematical creativity and problem-solving abilities. Theoretical exploration was followed by an analysis of correlations between metacognitive abilities and various ways of mathematical thinking. Various metacognitive teaching and learning methods used by many teachers at school were integrated for sharing. Also, the methods of learning application and assessment of metacognitive thinking were explored. The results are as follows: First, metacognitive abilities were positively related to 'reasoning, communication, creative problem solving and commitment' with direct and indirect effects on mathematical thinking. Second, various megacognitive ability-applied teaching and learning methods had positive impacts on definitive areas such as 'anxiety over Mathematics, self-efficacy, learning habit, interest, confidence and trust' as well as cognitive areas such as 'learning performance, reasoning, problem solving, metacognitive ability, communication and expression', which is a result applicable to top, middle and low-performance students at primary and secondary education facilities. Third, 'metacognitive activities, metaproblem-solving process, personal strength and weakness management project, metacognitive notes, observation tables and metacognitive checklists' for metacognitive learning were suggested as alternatives to performance assessment covering problem-solving and thinking processes. Various metacognitive learning methods helped to improve creative and systemic problem solving and increase mathematical thinking. They did not only imitate uniform problem-solving methods suggested by a teacher but also induced direct experiences of mathematical thinking as well as adjustment and control of the thinking process. The study will help teachers recognize the importance of metacognition, devise and apply teaching or learning models for their teaching environments, improving students' metacognitive ability as well as mathematical and creative thinking.

• Journal of Korean Society of Forest Science
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• v.85 no.2
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• pp.316-324
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• 1996

This study was conducted by relative time study to identify the allowance time and basic work time, which is together composed of the total work time, in the wage composition and work process composition. This study was done for the case of a basic one person a group from thinning treatment for some conifer species such as Japanese red pine, Japanese larch, pitch pine and Korean pine. 1. In order to apply the Japanese allowance time of four species to the general conifer case, the maximum value of allowance time composition value among those of four species was selected. The results are as follows: delay time for person 1.8%, rest time 14.1%, delay time for machine 12.5% and wating time 0.4%. The some of ratios of adjustment allowance time is 28.8%. 2. Estimated wage basis time table, which can be used for wage table or process table, was prepared by adding up adjusted general allowance time and standard work time estimated by estimation equation for each species through the time study.

• Korean Journal of Construction Engineering and Management
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• v.7 no.5
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• pp.64-76
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• 2006

Korea's overseas construction industry has been rather depressed by the weakened profitability as well as the sharp decrease of the market shares due to the lack of international competitiveness and the declined international market. There exist a lot of various risks in performing the overseas construction, and especially EPC projects, which entail complicated process from different parts, also require a sophisticated procurement and management skill. Subsequently, to survive in the competitive international market, we need to establish strategies to select potentially profitable projects at the initial stage of bidding process and to mitigate the high degree of risk exposure through contract negotiation and its adjustment. This research discusses the trend of environment in international construction markets. Then, it identifies the key factors that affect the profitability significantly through the structured surveys from 59 actual overseas projects, and it analyzes the key factors by using statistical methods. This research provides the profitability evaluation bases, with which overseas construction participants can forecast and analyze the risk more systematically, by eliciting profit-influencing factors using the result of statistical analysis, literature review and structuring their cause-and-effect relationships. The profitability casual hierarchy structure describes the profitability factors' hierarchy in details and their interrelationships. It also enables us to find out critical factors directly related to profitability aggravation through a qualitative and quantitative analysis. Ultimately, with this hierarchy structure as the base, the research will suggest how to develop the quantitative profitability forecasting model.