• Applied Chemistry for Engineering
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• 제7권1호
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• pp.203-213
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• 1996

In physical and reactive extraction system using equilibrium extraction equipment, the effects of extractants, concentration of extractant, and solvent on the degree of extraction were investigated. The organic acids used were acrylic acid and metacrylic acid. Extractants were n-octylamine(OA), di-n-octylamine(DOA), tri-n-octylamine(TOA) and tri-octylmetyl ammonium chloride(TOMAC ; Aliquat 336). We found that the degree of extraction for reactive extraction was 2~9 times than that for physical extraction and that effect of extractants on the degree of extraction of organic acid was the order of OA

• Journal of the Korea Fashion and Costume Design Association
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• 제17권3호
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• pp.197-206
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• 2015

Ghetto was originated from the concept of "Jewish Camp", the segregated Jewish residential area, and recently it refers to the black neighborhoods of the poor living conditions or slum. A region to form a unique culture distinguished from the adjacent area is also called as ghetto. The culture born in that region is called "ghetto culture", and from the cultural aspect it can mean a type of haven that allows the freedom and deviation of their own. In this study, the generating background and the characteristics of ghetto style especially to adolescents were examined, and celebrities' unique fashion styles that lead the public in the fashion diffusion process were analyzed. Through this, Ghetto culture was understood and the effects of the mass culture phenomena on fashion, symbolization, and an aesthetic value were examined. With this, it aims to help understand the effect of special local culture like "ghetto" on modern fashion and expand the design area. As a result of this study, the characteristics of ghetto style were as followings; 1. It is based on hiphop style; 2. The name brands are exposed conspicuously; 3. Caught eyes by unusually excessive decorations; 4. It expresses confidence and toughness through fashion beyond the resistance to the target who suppresses and humiliates themselves; 5. Ghetto culture is rapidly spread through media. To conclude, ghetto style is an expression of hope of the poor that they can gain wealth through impressing the public and drawing empathy just by their talent. Furthermore, ghetto style is an important cultural trend that has appeared as their wannabe and a powerful display method to express success.

• Journal of The Korean Association of Information Education
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• 제10권1호
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• pp.1-12
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• 2006

Sometimes the quantitative evaluation method does not explain students' full capacity in educational fields. In this point of view, performance assessment has been adapted widely since the assessment provides a comprehensive qualitative evaluation as well as quantitative evaluation. Portfolio is one of the most effective methods in performance assessment. However, the portfolio requires longer time in evaluation, physical space for storing data gathered from students. Electronic portfolio can overcome the above disadvantages of the traditional portfolio and increase students' ICT application capacity. The purpose of this study is to develop electronic portfolio assessment processing model and present concrete activities for each stage in the model. Our model consists of four stages, Preparation, Activity, Evaluation, and Application, respectively. Especially, our model is designed to provide different activities for students and teachers in each stage. Our model is expected to provide a good guidance to students, teachers and parents in understanding and utilizing portfolio assessment. Particularly our model will provide the comprehensive guidance to teachers in assessment process.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• 제18권6호
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• pp.262-274
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• 2019

The purpose of this study is to estimate the minimum proportion of probe vehicles for obtaining expressway traffic information using VISSIM, a micro traffic simulation model, between Yongin IC and Yangji IC on Yeongdong Expressway. 7,200 scenarios were created for the experiment, and 40 scenarios were adopted using the Latin hypercube sampling method because it was difficult to perform all the scenarios through experiments. The reliability of the experiment was improved by adding a situation when the general situation and the accident situation exist. In the experiments, the average travel time of probe vehicles at different market penetration rates were compared with the average travel time of the entire vehicles. As a result, the minimum market penetration rate of probe vehicles for obtaining expressway traffic information was found to be 45%. In addition, it is estimated that 25% market penetration rate of probe vehicle can meet 70% of traffic situations in accident scenario.

• Journal of the Korea Institute of Information and Communication Engineering
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• 제21권4호
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• pp.855-860
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• 2017

One of the most important issues in Wireless Sensor Networks is to save energy of the sensor node. But transmission latency is also the problem to solve for some applications such as military surveillance, object tracking. In these applications sensor node needs to send lots of data in limited time when an even such as object appearance occurs. So a delay efficient data transmission method is required. In this paper we propose a MAC protocol adequate for those applications. This paper proposed a low delay data transmission mechanism for military surveillance in wireless sensor networks. In the MAC protocol, a receiver node sends another beacon frame to sender node after receiving data packet. Using this second beacon frame, fast hop-to-hop transmission can be performed. Results have shown that the proposed MAC control mechanism outperformed RI-MAC protocol in the terms of latency.

• Proceedings of the Korean Geotechical Society Conference
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• 한국지반공학회 2004년도 춘계학술발표회
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• pp.28-35
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• 2004

Driven pile has the excellent bearing characteristics and good economics, so it is known as the comparative piling method. To use the advantages of driven pile fully, it is necessary to perform the proper construction management. Engineers must drive pile to the proper bearing layer with proper blow energy and measure the blow count and penetration per certain depth to analyze the bearing capacity and driveability. In conventional method, these parameters have been measured manually so it was difficult to get good accuracy. After PIR-D(Pile Installation Recorder-Driven Pile) was attached to the driving equipment, the hammer efficiency, blow count and penetration in blow/10cm were measured automatically. In this paper, to givethe rational judgement criteria of bearing layer, driveability, blow/10cm according to pile depth during pile driving, the some relationship between the driving resistance and ground layer distribution was analyzed. The ground investigation during piles (PHC ${\Phi}450,\;{\Phi}400\;&\;Steel\;Pile\;{\Phi}609{\ast}16t$) installation in the marine clay layer in Incheon, the sandy soil layer in Yongin and the tuff layer in Pusan was done. And measuring hammer efficiency not doing recently, we could compare hammer efficiency(Eh) by PIR-D and energy transfer ratio(ETR) by Pile Dynamic Analyzer(PDA).

• KIEAE Journal
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• 제16권3호
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• pp.47-55
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• 2016

Purpose: This study was aimed at providing the basic checklist as a means to assess the crime risk in physical environment of the pedestrian passage at residential area. Method: For this purpose, the preliminary checklists were selected according to the review of the precedent studies of checklists in exterior pedestrian passage. The usefulness and the importance of the preliminary checklists were analyzed through the seven expert group meetings, the 87 questionnaires survey of the crime experts & the architectural/urban experts, preliminary assessment and field survey. Results: The assessment categories of checklists were sorted into six types, i.e. spatial structure & function, lighting, landscaping, security facilities, other facilities and cleaning & maintenance. The 49 checklists were proposed according to the assessment categories. The final checklists were divided key checklists and general checklists based on the results of experts' weighting of each list item. There were significant differences between crime experts' weighting and architectural/urban experts' weighting in several checklists, i.e. dividing between pavements and streets, the brightness of light, white light.

• Korea Journal of Hospital Management
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• 제23권1호
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• pp.28-40
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• 2018

Purpose: The purpose is to understand the perception of medical providers at tertiary hospitals in Seoul on the importance-performance of the reform on a doctor-designation system, and to provide the policy suggestion of the perception on such a system. Methodology: To achieve the purpose, this study utilized structured survey tools to conduct a questionnaire survey of nursing, administrative and medical technology professionals at six tertiary hospitals in Seoul. An importance-performance analysis was utilized for an analysis that showed the perception of the reform on a doctor-designation system. Findings: First, it was identified that those medical providers had the highest perception of the importance about the performance of the reform on a doctor-designation system. Second, according to the result of action grid of an importance-performance analysis (IPA), it can be identified that in the 2nd stage of 'Concentrate here' included are the items as to design and effect of medical care quality and subsidies & patient infection and safety and control fees, effect of income security of the method for compensating for loss established by the government and offering sufficient information on general medical services and doctor-designation medical services. In the 1st stage of 'Keep up the Good Work', and the 2nd stage of 'Concentrate here' included is the item as to the performance of patients of the reform on a doctor designation system. Practical Implications: There could be identified the effect of the reform bill on the perception of medical providers. It is expected that a better environment would be provided for patients to use a hospital and for medical providers to offer medical services, if the goverment makes efforts to improve methods for compensating for loss and continuous monitoring of the performance of patients.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제29권4호
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• pp.212-218
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• 2003

Matrix metalloproteinases (MMPs) play an important role in the normal morphogenesis, maintenance, and repair of matrix and also have important functions in pathologic conditions characterized by excessive degradation of extracellular matrix, such as rheumatoid arthritis, osteoarthritis, periodontitis and in tumor invasion and metastasis. In this study, expression of MMP-1 and -2 mRNA in retrodiscal tissue of the temporomandibular joint (TMJ) was examined and compared with magnetic resonance imaging (MRI) and surgical findings. MMP mRNAs in the retrodiscal tissue samples were detected by reverse transcription - polymerase chain reaction. TMJ internal derangement (ID) was categorized as normal disc position, disc displacement with reduction, early stage of disc displacement without reduction (DDsR) and late stage of DDsR. TMJ osteoarthrosis (OA) was classified with normal, mild and advanced OA. The amount of synovial fluid collection was divided into not detected, small, large and extremely large amount on MR T2-weighted imaging. Perforation and adhesion were examined during open surgery of the TMJ. Six out of 37 samples were excluded because of little amount of extracted total mRNA. MMP-2 mRNA was detected whole joints, and so the MMP-2 mRNA seems to be expressed normally in retrodiscal tissue. However, MMP-1 mRNA was expressed in 8 of 31 joints. Frequencies of MMP-1 mRNA expression according to the TMJ IDs, amount of synovial fluid and surgical findings made no significant difference. MMP-1 mRNA was detected more frequently in OA groups (7/16 joints, 43.8%) than in normal bony structure group (1/15 joints, 6.7%). Expression of MMP-1 mRNA in retrodiscal tissue might be related with OA of the TMJ.

• Journal of the Korean School Mathematics Society
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• 제10권1호
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• pp.129-148
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• 2007

Recent reform movement in mathematics education has focused not only on the curriculum development but also on teachers' learning or professional development. Whereas various theoretical paradigms call for different programs of professional development for teachers, one of the common emphases is on the pedagogical content knowledge [PCK] which encompasses contents and methods to teach. Against this background, this study developed comprehensive instructional materials for the purpose of fostering PCK in mathematics for elementary school teachers with 17 essential learning themes such as fraction, plane geometry, and area. Each loaming theme was first summarized on the basis of literature reviews and surveys in terms of knowledge in mathematics contents, knowledge in teaching methods, and knowledge in students' mathematical understanding and learning. Each theme was then analyzed in detail on how it was represented in the national curriculum and its concomitant textbooks along with workbooks. Finally, this report included a reconstruction of one unit in textbooks per each learning theme, followed by teaching notes and suggestions from classroom implementation. This was intended for teachers to apply what they might loam from this material to their actual mathematics instruction. Given the page limit, this paper dealt only with the learning theme of ratio.