• Resources Recycling
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• v.26 no.6
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• pp.65-72
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• 2017

APT (Ammonium paratungstate) is widely used in various industries such as metal cutting tools, drill bits, mining tools, and military inorganic materials. In order to produce high purity APT(S), an impurity purification step in an aqueous $Na_2WO_4$ convert $H_2WO_4$ solution is required. It is difficult to remove impurity Na of 200 ppm or less when $H_2WO_4(S)$ is prepared by adding HCl(Aq) to an aqueous solution of $Na_2WO_4$, which is a well-known conventional wet method. However, in this study, a more economical and efficient method of removing Na through electrodialysis using a cationic membrane was studied. A large amount of Na in aqueous solution of $H_2WO_4$ due to $Na_2CO_3(S)$ which was added to dissolve waste tungsten carbide drill and scrap was removed to 20ppm or less through electrodialysis process, and it was confirmed that the effect of Na removal was great when using electrodialysis.

• Journal of the Economic Geographical Society of Korea
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• v.4 no.1
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• pp.37-60
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• 2001

The record industry, which consists of the cultural industries, has been deeply interrelated with the innovations of the science and the technologies. In Korea, the record industry has been developed dramatically since the late 1980s, and thus it has formed a huge business, and has also brought a lot of accompanying economical effects. The record industry is constituted with four circulation steps such as producing, manufacturing, wholesaling and retailing, which follow the different locational orients, respectively. The purpose oi this study is to investigate the locational characteristics of each step. Because of the shortage of the data, this study based on the direct data from field studies, interviews, and surveys, as well as the existing document data. The results of this research are summarized as following: the record industry shows strong concentrations in Seoul and the surrounding areas. It also shows the spatial linkage with other industries that are necessary for the production, advertisement, and sales of records. The locations of the record producers are affected by the location of broadcasting stations. Therefore, they are concentrate in Kangnam and Yeouido, where many broadcasting stations are located.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.7
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• pp.2371-2385
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• 2010

What are the success factors of IT venture entrepreneur that through initial phase and enter to the growth phase ? Both the duration of jobless growth and the economic recession are worsening employment market. Entrepreneurship is be proposed to a method for creating jobs and reducing the economic gap. Research on Entrepreneurship and the support of government policy has already been operated for a long time ago. Research on growth and duration of the entrepreneur in initial phase, compared with growth phase are insignificant in quantity or quality. Therefore, this study researches essential factors about growth and duration of the entrepreneur in the initial phase through cases related them. entrepreneur of this subject are classified the hardware development group and the software development group associated with manufacturing characteristic funded existence. There is a research on evaluation factors about selection and result evaluation of selecting Entrepreneur. And this can be investigated by studying to Entrepreneur's growth and duration in initial phase. There are affecting factors about growth and duration of first step. And they are divided by internal, external, synthetic, and characteristic factors of growth phase. The result of this study is be used to develop pre-established educational program, consulting guidelines and establish support policy.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.11
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• pp.4924-4931
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• 2011

This research performed to evaluate a production processes reporting by the HACCP system of green vegetable juice products, containing lactic acid bacteria, stage of processing raw materials agricultural products and production facilities of general bacteria and pathogenic micro organism. General bacteria are found from four samples of storage of agricultural products at process stage and water was detected 8.67~14.67 CFU/ml. However, all samples were detected less than 105 CFU/ml as a legal standards after the process of UV sterilization. For the outcome of experiment of E.coli, E.coli O157:H7, B.cereus, L.moonocytogenes, Salmonella spp, Staph.aureus as the food poisoning bacterial, E.coli was detected until UV pre-step process in storage process and B.cereus was detected partly till 1st washing. Since all bacterial, Yeast and Mold are detected in main materials, pre-control method is a necessary to establish for decreasing with a number of initial bacteria of main materials and it is considered to establish the effective ways of washing and sterilization such as production facilities for cross contamination prevention of bacteria and Sthaphylococcus. Based on above results, the process of UV sterilization should be managed with CCP as an important process to reduce or eliminate the general and food poisoning bacterial of green vegetable juice products, including lactic acid bacteria. Therefore, it is considered to need an exhaustive HACCP plan such as control manual of UV sterilization, solution method, verification, education and training and record management.

• Land and Housing Review
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• v.12 no.3
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• pp.67-78
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• 2021

After World War II, modular housing was developed as a means of quickly and efficiently meeting the housing supply demand. For the past 30 plus years, efforts have been made to improve modular housing in South Korea and to increase their competitiveness in the housing market. This study investigated modular houses based on a steel framed rahem structure which provides a flexible floor plan where walls are easily reconfigured to create rooms of various sizes and functions. Similar to the factory production methods used in the automotive industry, the modular housing industry can also benefit by standardizing such aspects as building components, manufacturing and construction methods, materials, process management, and floor plans. This study examined the feasibility of using a 3m × 3m module for developing various floor plans which are easy to produce and transport. Each 3m × 3m module can be configured to meet different living needs resulting in a complete home when multiple modules are connected. The module configurations can be varied to meet ground transportation and crane limitations. This study found that a 3m × 3m steel framed modular unit is a promising step towards providing residents with plans that meet their living preferences while improving and increasing the supply of modular houses.

• Korean Journal of Heritage: History & Science
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• v.37
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• pp.267-284
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• 2004

As an initial step to understand the transitions in Korean bronze technology the present study has examined metallurgical microstructures of 8 artifacts excavated from the Silla Wang-Gyong site in Kyongju. Important trends have been found in alloy compositions and also in manufacturing processes. In the design of alloys, the Sn content was apparently changing toward the peritectic point, 22 mass %, of the Cu-Sn phase diagram while the Pb addition was intentionally avoided. This trend in composition was found accompanied by the introduction, subsequent to casting, of such special thermo-mechanical treatments as quenching and forging in artifact manufacture. In addition, the Sn content in alloys containing a significant amount of As was relatively low and no evidence of forging was observed in them. The use of quenching and forging and the rejection of Pb and As from alloys are all necessary requirements if the brittle nature of high Sn alloys is to be overcome in bronze working. This paper will show that the Wang-Gyong era corresponds to that of innovations leading to the technical climax in Korean bronze tradition, which has been maintained up to the present.

• Clean Technology
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• v.28 no.3
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• pp.227-231
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• 2022

The demand for high-voltage power devices is rising in various industries, but especially in the transportation industry due to autonomous driving and electric vehicles. IGBT module parts of 3.3 kV or more are used in the power propulsion control device of electric vehicles, and the procurement of these parts for new construction and maintenance is increasing every year. In addition, research to optimize high-voltage IGBT parts is urgently required to overcome their very high technology entry barrier. For the development of high-voltage IGBT devices over 3.3 kV, the resistivity range setting of the wafer and the optimal conditions for major unit processes are important variables. Among the manufacturing processes to secure the optimal junction depth, the optimization of the diffusion process, which is one step of the unit process, was examined. In the diffusion process, the type of gas injected, the injection time, and the injection temperature are the main variables. In this study, the range of wafer resistance (Ω cm) was set for the development of high voltage IGBT devices through unit process simulation. Additionally, the well drive in (WDR) condition optimization of the diffusion process according to temperature was studied. The junction depth was 7.4 to7.5 ㎛ for a ring pattern width of 23.5 to25.87 ㎛, which can be optimized for supporting 3.3 kV high voltage power devices.

• Journal of Intelligence and Information Systems
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• v.29 no.1
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• pp.265-288
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• 2023

Process mining has generally analyzed the default logs of Information Systems such as SAP ERP, but as the use of automation software called RPA expands, the logs by RPA bots can be utilized. In this study, the actual status of RPA automation in the field was identified by applying RPA bots to the work of three domestic manufacturing companies (cosmetic field) and analyzing them after leaving logs. Using Uipath and Python, we implemented RPA bots and wrote logs. We used Disco, a software dedicated to process mining to analyze the bot logs. As a result of log analysis in two aspects of bot utilization and performance through process mining, improvement requirements were found. In particular, we found that there was a point of improvement in all cases in that the utilization of the bot and errors or exceptions were found in many cases of process. Our approach is very scientific and empirical in that it analyzes the automation status and performance of bots using data rather than existing qualitative methods such as surveys or interviews. Furthermore, our study will be a meaningful basic step for bot behavior optimization, and can be seen as the foundation for ultimately performing process management.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.8 no.11
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• pp.215-222
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• 2018

In this paper, the research on the energy storage system adapting super-capacitor has been performed. The most advanced features compared to the conventional lead-acid battery systems is that it can obtain high power capability due to the super capacitor power characteristics. The suggested system can attain high power in short times and achieve high power quality improvements. The application areas are power quality improvement system, motor start power which requires high power during transient times. The energy conversion system consists of bi-directional converter and inverter and advantages of high speed, high power charging and discharging performances. The design steps for the two loop controller of the bi-directional inverter are suggested and verified by the experiment and manufacturing. The two loop controller design starts from linearized transfer function which is calculated from the state averaging model including state decoupling method. The current controller requirements are 20% overshoot and settling time and voltage controller are no overshoot and settling time which is 10 times longer than current controller. The design is verified from the step input response. The designed controllers have unity power factor characteristics and thus can improve the power quality of the grid. It also has fast response time and zero steady state error.

• The Journal of Korean Academy of Prosthodontics
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• v.53 no.1
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• pp.19-25
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• 2015

Nowadays, CAD/CAM is broadly used in dentistry for inlays, crowns, implant abutments and its spectrum is expanding to complete dentures. Utilizing CAD/CAM to fabricate complete dentures is expected to decrease chair time and the number of visits, thus decreasing total fabrication time, expenses and errors caused during fabrication processes. One of the systems using CAD/CAM, DENTCA$^{TM}$ CAD/CAM denture (DENTCA Inc. Los Angeles, USA) scans edentulous impressions, designs dentures digitally, fabricates try-in dentures by 3D printing and converts them into final dentures. Patients can wear final dentures after only 2 - 3 visits with satisfying adaptation. This case report introduces a 71-year-old male patient who visited to consult remaking of existing old dentures. Residual teeth with bad prognosis and root remnants were extracted and the patient used reformed existing mandibular denture for 2 months. And then DENTCA system started. One-step border molding was done using conventional tray of adequate size provided by DENTCA system and wash impression was taken. Gothic arch tracing was completed based on the vertical dimension of existing dentures. Both maxillary and mandibular trays were placed to the resultant centric relation and bite registration was taken. Then DENTCA scanned the bite registration, arranged the teeth, completed the festooning and fabricated the try-in dentures by 3D printing. The try-in dentures were positioned, occlusal plane and occlusal relations were evaluated. The try-in dentures were converted to final dentures. To create bilateral balanced occlusion, occlusal adjustment was done after clinical remounting using facebow transfer. The result was satisfactory and it was confirmed by patient and operator.