• Korean Chemical Engineering Research
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• v.44 no.5
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• pp.528-534
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• 2006

The purpose of this paper is to investigate the optimal operating condition for the hydrogen production by biogas reforming using the plasmatron induced thermal plasma. The component ratio of biogas($CH_4/CO_2$) produced by anaerobic digestion reactor were 1.03, 1.28, 2.12, respectively. And the reforming experiment was performed. To improve hydrogen production and methane conversion rates, parametric screening studies were conducted, in which there are the variations of biogas flow ratio(biogas/TFR: total flow rate), vapor flow ratio($H_2O/TFR$: total flow rate) and input power. When the variations of biogas flow ratio, vapor flow ratio and input power were 0.32~0.37, 0.36~0.42, and 8 kW, respectively, the methance conversion reached its optimal operating condition, or 81.3~89.6%. Under the condition mentioned above, the wet basis concentrations of the synthetic gas were H2 27.11~40.23%, CO 14.31~18.61%. The hydrogen yield and the conversion rate of energy were 40.6~61%, 30.5~54.4%, respectively, the ratio of hydrogen to carbon monoxide($H_2/CO$) was 1.89~2.16.

• Proceedings of the Korean Society of Crop Science Conference
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• 1998.10a
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• pp.288-312
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• 1998

In Korea, chemical fertilizers and agricultural chemicals have had a significant impact on food production and these are today thought to be an indispensable part of modern agriculture. On the other hand, socioeconomical and IMF and WTO status in Korea are constant reminders of the vulnerability of our fossil fuel dependent agriculture. A new crop production system to improve economic, environmental and production efficiency must be exploited. Our particular concern has been given to an integrated cropping system involving recycling of crop residues, soil and N management, biological N fixation and multipurpose legumes. As a new integrated crop production system, a no-till direct-sown rice-vetch relaying cropping system has been proposed in this paper. The formulation of this system is based on the conception that N fertilizers being neither limitlessly available nor affordable, the current high-input crop production systems have produced troubled results severe labour shortage ill rural areas, balance of payment, environmental degradation and reduction of human health far exceed economic concerns. A natural and logical consequence is that long-term sustainability of agricultural systems must rely on the use and effective management of internal resources. Based on the information obtained throughout a series of experiments last years we have proved that the no-till direct-sown rice-vetch relaying cropping system dictates biological alternative which can augment, and in some cases replace, N fertilizers. Comprehensive discussions were made for the proposed system and it concluded that the system can offer an economically attractive and ecologically sound means of reducing external nitrogen input and improving the quality and quantity of internal resources, and consequently improving the farmers as well as the national returns.

• Proceedings of the Technology Innovation Conference
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• 1996.12a
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• pp.241-264
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• 1996

This article introduces the five functions of the national innovation system (NIS). As the national innovation system is a kind of social systems in the national level, the five generic functions of open system-production boundary spanning, maintenance, adaptation management functions-are applied to the NIS. The production function is the primary process, which produces innovative products and services of the NIS. The boundary spanning function is the function of procuring the input and disposing the innovation output or aiding in these process. Experienced R&D human resources, R&D funds, technology etc. belong to the input of the NIS. The maintenance function is responsible for the smooth operation and upkeep of the system in terms of various conditions. The adaptive function is to help the system change and adapt, scan the environment for problems, opportunities, and technological developments. It faces outward for the survival of the system from the long-term view. The management function carries out planning and controlling the overall activities for the other four functions in order to run the system. Finally it discuses implications for the diagnosis and the decision making process of S&T policy.

• Journal of Korean Institute of Industrial Engineers
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• v.23 no.3
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• pp.501-514
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• 1997

Manufacturing is fast entering a new age of industrial excellence that is being called "Agile Manufacturing." The goal of Agile Manufacturing is to link customers, suppliers, and the manufacturing system into a super-efficient confederation to produce a variety of products quickly and at a low cost. In order to improve the quality of the study of production input control(PIC) in a job shop manufacturing system by reducing the significant gap between research models and models of actual manufacturing systems, the previous line of research on PICs in a job shop manufacturing system is extended by integrating customers and suppliers with the manufacturing system. Then, a set of measures is developed to evaluate PICs, measures that reflect concerns of customers and suppliers as well as concerns of the manufacturer. Also, a weighted overall measure (with various cases to represent different possible weights of manufacturer's emphasis on the performance measures) is used to synthesize all the performance measures. Then, for each case, various existing PICs are evaluated in combination with various priority dispatching rules(PDRs).

• Journal of Korea Technology Innovation Society
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• v.8 no.spc1
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• pp.499-524
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• 2005

The economic spillover effect from technology self-reliance of NSSS(nuclear steam supply system) by Korea Atomic Energy Research Institute was evaluated. Both production spillover effect and value added spillover effect were estimated by using Input-Output table. The production spillover effect from technology self-reliance of NSSS was estimated as 135 trillion Won during 1986-2015, while the value added spillover effect was 69 trillion Won during the same period. Besides, it was found that the technology self-reliance made great contribution to unquantifiable economic benefits such as enhancement of overall nuclear technology level, improvement of the role in international nuclear society, and improved potential to nuclear technology export.

• Journal of environmental and Sanitary engineering
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• v.15 no.4
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• pp.84-90
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• 2000

5L laboratory-scale anaerobic digester was used to study the effects of food size and washing rate of food waste on the mixed digestion with sewage sludge. Food waste was crushed with particle diameters of 4mm and 2mm and washed two to three times, and seven to eight times before feeding the batch digester. The digester with crushed of washed food waste showed better performance than that with uncrushed of unwashed to produce methane gas of reduce volatile solids. The digester with 2mm food waste showed 17.4% higher VS/TS reduction rate and 18ml higher methane production rate per gram VS input than that with uncrushed food waste, where VS and TS are volatile solid and total solids in the liquid effluent, respectively. Also food waste crushed eight times gave 8% higher VS/TS reduction rate and 11ml higher methane production rate per gram VS input than unwashed food waste.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.213-214
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• 2006

The CAM software for drill grinding has been developed to save time, reduce cost for tool manufacturing and obtain accuracy of tool. In this paper, the developing software for drill will be presented including calculation and simulation of machining processes using 5-axes CNC grinding machine. The algorithm fer helical flute grinding was applied into calculating NC data. The software will generate NC code for machining by using input data of tool geometry, wheel geometry, wheel setting, machine setting. These NC code files will be used in simulator as input file. The simulator provides some functions for simulating machining processes, inspecting and measuring tool geometry.

• Journal of the Korea Society of Computer and Information
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• v.5 no.2
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• pp.158-164
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• 2000

The purpose of this study is concerned with evaluating management performance in electronics and communication companies using DEA(Data Envelopment Analysis) DEA is a linear programming based technique for measuring the relative performance of organizational units where the Presence of multiple inputs and outputs makes comparisons difficult. In this research. input variables are raw-material costs, number of employees, and production capacity Real production, sales revenue and net earning are suggested as output variables. Management performance of most companies are increased or equal during 97 and 98 fiscal year and input & output variables show high correlation.

• Journal of the Korean Society for Precision Engineering
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• v.28 no.9
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• pp.1011-1017
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• 2011

Servo control loops are a core part in the control architecture of machine tools. Servo control loops manage acceleration, velocity and position of all the axes in a machine tool based on commands. The performance of servo control loops sets the basis for quality of production paris and cycle time reduction. First, this paper presents a general control architecture of machine tools and several control schemes in literature, which can be applicable to machine tools control; including Zero Phase Error Tracking Control (ZPETC) and Cross Coupling Control (CCC). After that, modem control strategies to mitigate the problem of high speed machining are reviewed. In high speed machining, high accelerations excite the machine structure up to high frequencies, thereby exciting the structure's modes of vibration. These structural vibrations need to be damped if accurate positioning or trajectory following is required. Input shaping is an attractive option in dealing with structural vibrations. The advantages and drawbacks of using input shaping technique for machine tools are discussed in detail.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.11
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• pp.141-150
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• 2000

Continuously variable transmission(CVT) combined differential gear unit has many advantages, which are the decrease of CVT size, the increase of overall efficiency, the extension of speed ratio range, and the generation of geared neutral. It is known that such CVT can be classified into the input coupled type and the output coupled type according to the coupling location of continuously variable unit(CVU). In this paper, six different configurations of input coupled type CVT combined V-belt CVU and 2K-H I type differential gear unit are proposed. Some useful theoretical formula related to speed ratio, power flow and efficiency are derived and analyzed. The propriety of derived formula and theoretical analysis are proven by various experiments.