• 소성∙가공
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• 제12권5호
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• pp.440-448
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• 2003

Sheet or plate bending is one of the most important industrial metal forming processes. Considerable attention has been focused on gaining a better understanding of bending characteristics. One of defaults in bending process is the springback. In this study, the springback characteristics of tailor-welded strips in U-bending process was investigated. Furthermore, effect of the process variables such as the geometry of the tools, thickness combination of workpiece, and welding prcoessing on springback were experimentally clarified. First, tailor-welded strips are joined by the laser welding process and consisted of two types of thickness combinations of the SCPl sheet, $0.8t{\times}1.2t$ and $0.8t{\times}1.6t$ to investigate the effect of different thickness combination on the springback. Secondly, two different directionly welded strips, one was welded along the centerline of the strip-width and the other was along the centerline of strip-length, were adopted to compare the effects of the location of weld line on the springback. Some cases of the experimental results were compared to the results simulated by using a commercial FEM code, PAM-STAMP and the theoretical results using the springback formula as well.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2008년도 춘계학술대회 논문집
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• pp.374-377
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• 2008

Magnesium alloy sheets are usually formed at temperatures between $150^{\circ}C$and $300^{\circ}C$ because of their poor formability at room temperature. In the present study, the formability of AZ31B magnesium alloy sheets was investigated by the analytical and experimental approaches. First, tensile tests and the limit dome height test were carried out at elevated temperatures to get the mechanical properties and forming limit diagram, respectively. And then deep drawing of cross shaped die was tried to get the minimum corner radius and forming limit at specific temperature. Blank shape, punch velocity, minimum corner radius, fillet size, etc, were determined by finite element analysis physical try-outs. Especially, optimum punch and die temperature were suggested through the temperature-deformation analysis using Pam-stamp.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2008년도 춘계학술대회 논문집
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• pp.513-516
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• 2008

We have replicated nanopillar arrays using injection molding process of active heating and cooling method by several peltier devices. The injection melding has a high accuracy ed good reproducibility that are essential for mass production at low cost. Conventional molding processes widely use the water-based mold heating and air cooling methods. However, in case of replication for nano-patterned structures, it caused several defects such as air-flow mark, non-fill, sticking and tearing. In this study, periodic nano-scale patterns are replicated by using injection molding with Peltier devices. Porous nano-scale patterns, which have pore diameter range from 120nm to 150nm, were fabricated by using anodizing process. Periodic nano-pore structures ( $20mm\;{\times}\;20mm$) were used as a mold stamp of injection molding. Finally, PMMA with nanopillar arrays was obtained by injection molding process. By using the Peltier devices, the temperature of locally adiabatic molds can be dramatically controlled and the quality of the molded patterns can be slightly improved.

• Molecules and Cells
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• 제40권5호
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• pp.371-377
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• 2017

Despite the importance of the receptor activator of nuclear factor (NF)-kappaB ligand (RANKL)-RANK signaling mechanisms on osteoclast differentiation, little has been studied on how RANK expression is regulated or what regulates its expression during osteoclastogenesis. We show here that insulin signaling increases RANK expression, thus enhancing osteoclast differentiation by RANKL. Insulin stimulation induced RANK gene expression in time- and dose-dependent manners and insulin receptor shRNA completely abolished RANK expression induced by insulin in bone marrow-derived monocyte/macrophage cells (BMMs). Moreover, the addition of insulin in the presence of RANKL promoted RANK expression. The ability of insulin to regulate RANK expression depends on extracellular signal-regulated kinase 1/2 (ERK1/2) since only PD98059, an ERK1/2 inhibitor, specifically inhibited its expression by insulin. However, the RANK expression by RANKL was blocked by all three mitogen-activated protein (MAP) kinases inhibitors. The activation of RANK increased differentiation of BMMs into tartrate-resistant acid phosphatase-positive ($TRAP^+$) osteoclasts as well as the expression of dendritic cell-specific transmembrane protein (DC-STAMP) and d2 isoform of vacuolar ($H^+$) ATPase (v-ATPase) Vo domain (Atp6v0d2), genes critical for osteoclastic cell-cell fusion. Collectively, these results suggest that insulin induces RANK expression via ERK1/2, which contributes to the enhancement of osteoclast differentiation.

• 한국의사학회지
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• 제31권2호
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• pp.17-26
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• 2018

, which is part of The Oriental Library collection in Japan, is a record that Hwang Dosoon (黃道淳) visited China in 1894. In this paper, several facts have proved that the author of the is Hwang Dosoon. First, the records in the and coincide with each other. Second, I found Hwang Dosoon on the list of the written by Shim Donyoung and confirmed that one of the characters in his name was mis-spelled. Third, I confirmed that the date and place of the reports in coincided with the . Fourth, the name on the ownership stamp in the has been identified as Hwang Dosoon. The consists of five parts. They are preface, diary, appendix, list, and itinerary. The records are from August 7, 1849 to October 16, but briefly mentions the contents of the itinerary from July 17 to December 1. This book is a book written by Hwang Dosoon himself kept in his own collection, and is highly valuable because it is the only relic of Hwang Dosoon.

• 정보보호학회논문지
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• 제22권4호
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• pp.913-921
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• 2012

유헬스케어 서비스의 급속한 발전과 보급에 힘입어 유헬스케어 서비스 기술은 많은 변화가 이루어지고 있다. 그러나 유헬스케어 서비스는 보안상의 문제로 인하여 사용자의 민감한 의료정보가 제3자에게 유출되고 사용자의 프라이버시가 사용자의 동의없이 침해되는 문제가 발생되고 있다. 본 논문에서는 유헬스케어 환경에서 사용되고 있는 환자의 프라이버시 정보에 안전하게 접근하기 위해서 병원관계자의 권한 및 접근 레벨에 따라 환자의 생체정보를 분산 접근하는 모델을 제안한다. 제안 모델은 환자의 생체정보의 접근을 제어하는 동시에 타임스탬프를 통해 DoS 공격 예방과 최신성을 유지한다. 또한, 제안 모델은 병원관계자를 중앙에서 서버가 통합 관리하는 동시에 병원마다 병원관계자의 권한 및 레벨에 따라 접근을 제어하기 때문에 환자의 프라이버시 침해 및 의료정보 유출을 예방한다.

• 한국멀티미디어학회논문지
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• 제24권1호
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• pp.95-105
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• 2021

In the case of laptops and tablet PC's that replace desktop, it uses the Windows operating system to provide various functions depending on operating system dependency, the Windows operating system does not support real-time processing because it uses multi-level feedback queue scheduling that extends round-robin scheduling. Also, since the initial value of Local APIC Counter can not be obtained from the Windows 8, the real-time processing function provided through the existing RTiK does not work. In this paper, we calculate Local APIC Counter value by using MSR_FSB_FREQ register to support real-time processing function on tablet PC's. We designed and implemented RTiK+, which provides real-time processing function to guarantee the periodicity by calculating the operation time of accurate timer. In order to verify and evaluate the performance of the implemented the RTiK+, the period was measured by using the Read Time-Stamp Counter(RDTSC) instruction and it was confirmed that it operates normally at 1ms and 0.1ms period.

• 대한약침학회지
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• 제24권4호
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• pp.182-190
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• 2021

Objectives: The purpose of this study was to analyze the microneedle therapy system (MTS) and its research methods for the past 10 years in Korea. Methods: Data on microneedle therapy system were collected using NDSL, KISS, RISS, and OASIS electronic databases from January 2010 to August 2021. "microneedle," "derma stamp," "microneedle therapy system" were used as the keywords. The present study, however, excluded data that were 1) unrelated to the microneedle therapy system, 2) from review/meta/protocol studies, and 3) from overseas studies. Data selected through the primary screening process, animal studies, case reports, and clinical data were included in the analysis. However, information data not related to the microneedle therapy system were excluded from the study. Results: Among the MTS-related papers published from January 2010 to August 2021, 7 animal research, 2 clinical trials, and 10 case studies were published. Based on the research topics, there were 8 papers on skin improvement and skin diseases, 7 papers on hair growth and hair loss, 3 papers on stability, and 1 paper on peripheral facial paralysis. Conclusion: Most of the studies related to MTS focused on skin, hair, and stability. The effect of MTS on hair growth and skin improvement has been confirmed, and it has been proven to have significant effects on the treatment of acne, acne scars, and hair loss in clinical practice. No serious side effects were observed during the MTS treatment, and the safety assessment confirmed that it was safe for use.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 1997년도 Proceedings International Workshop on New Video Media Technology
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• pp.75-81
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• 1997

A new DTPP (Desk-Top Program Production) system has been developed that enables multiple program producers (directors) working at different locations to collaborate over a computer network and prepare a single program for broadcasting. In this system, information is shared among users by exchanging data edited on non-linear editing terminals in program post-production work over a network in real time. In short, the new DTPP system provides a collaborative work space for producing TV programs. The system does not make use of a special server for collaborative work but rather multiple interconnected editing terminals having the same functions. In this configuration, data at a terminal which has just been edited by some operation is forwarded to all other connected terminals for updating. This form of information sharing, however, requires that some sort of data synchronizing method be established since multiple terminals are operating on the same data simultaneously. We therefore adopt a method whereby the system synchronizes the clocks on each terminal at the time of connection and sends an operation time stamp together with edited data. This enables most recently modified data to be identified and all information on all terminals to be updated appropriately. This paper provides an overview of this new collaborative DTPP system and describes the techniques for exchanging edited data and synchronizing data.

• 소성∙가공
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• 제32권3호
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• pp.122-128
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• 2023

As electric vehicles (EV) have increasingly replaced the conventional vehicles with internal combustion engines (ICE), most of automotive makers are actively devoting to the technology development of EV parts. Accordingly, the manufacturing process for power source has been also shifting from engine/transmission to EV motor/reducer system. However, lack of experience in developing the EV motor still remains as a technical challenge. In this paper, we employed the forming simulation based on finite element modeling to solve this problem. In particular, in order to increase the accuracy of the forming simulation, we introduced the elastic-plastic constitutive model parameters for polymer-copper hybrid wire by investigating the individual strain-stress curves, and elastic modulus of polymer and copper. Then, the reliability of modeling procedure was confirmed by comparing the simulated results with experiments. Finally, the identified mechanical properties and finite element modeling were applied to a hairpin forming process, which involves multiple deformation paths such as bending, pressing, widening, and twisting. The proposed numerical approach can replace common experience or experiment based trials by reducing production time and cost in the future.