• 한국융합학회논문지
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• 제11권1호
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• pp.285-291
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• 2020

오늘날 현대 여성들은 여성성을 가장 극대화할 수 있는 가슴 성형에 대한 여성들의 관심은 더욱 커지고 있다. 그러나 유방 확대술은 부작용에 대한 논란이 지속되고 있으며 많은 사람들이 두려워하고 있는 수술 중의 하나이다. 이러한 부분을 보완하고자 본 연구는 한국여성 23명을 대상으로 E사의 비수술적인 유방 확대 프로그램인 가슴 스트레칭 기기를 10주동안 사용하여 가슴이 형태적 변화를 연구하였다. 실험 결과로 체중의 변화는 없었으나 가슴의 컵 사이즈 확대, 유방 직경 증가, 유방 부피가 증가하였으며 가슴 탄력의 변화는 거의 없는 것으로 확인되었다. 가슴 외부 연부조직 확장 시스템이 동양인 한국 여성에게 가슴의 형태적 변화에 도움이 되는 것으로 확인되었다. 그러나 이 시스템은 일정 기간 사용 시간을 준수하기 위해 사회적인 생활에 제약을 받을 수 있으며 개인적인 노력이 뒷받침되어야 한다.

• 한국정밀공학회지
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• 제26권1호
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• pp.146-154
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• 2009

In recent tissue engineering field, it is being reported that the fabrication of 3D scaffolds having high porous and controlled internal/external architectures can give potential contributions in cell adhesion, proliferation and differentiation. To fabricate these scaffolds, various solid free-form fabrication technologies are being applied. The solid free-form fabrication technology has made it possible to fabricate solid free-form 3D microstructures in layer-by-layer manner. In this research, we developed a multi-head deposition system (MHDS) and used design of experiment (DOE) to fabricate 3D scaffold having an optimized internal/external shape, Through the organization of experimental approach using DOE, the fabrication process of scaffold, which is composed of blended poly-caprolactone (PCL), poly-lactic-co-glycolic acid (PLGA) and tricalcium phosphate (TCP), is established to get uniform line width, line height and porosity efficiently Moreover, the feasibility of application to the tissue engineering of MHDS is demonstrated by human bone marrow stromal cells (hBMSCs) proliferation test.

• 산업경영시스템학회지
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• 제38권3호
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• pp.100-107
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• 2015

Recently as the manufacturers want competitiveness in dynamically changing environment, they are trying a lot of efforts to be efficient with their production systems, which may be achieved by diminishing unplanned operation stops. The operation stops and maintenance cost are known to be significantly decreased by adopting proper maintenance strategy. Therefore, the manufacturers were more getting interested in scheduling of exact maintenance scheduling to keep smooth operation and prevent unexpected stops. In this paper, we proposedan integrated maintenance approach in injection molding manufacturing line. It consists of predictive and preventive maintenance approach. The predictive maintenance uses the statistical process control technique with the real-time data and the preventive maintenance is based on the checking period of machine components or equipment. For the predictive maintenance approach, firstly, we identified components or equipment that are required maintenance, and then machine parameters that are related with the identified components or equipment. Second, we performed regression analysis to select the machine parameters that affect the quality of the manufactured products and are significant to the quality of the products. By this analysis, we can exclude the insignificant parameters from monitoring parameters and focus on the significant parameters. Third, we developed the statistical prediction models for the selected machine parameters. Current models include regression, exponential smoothing and so on. We used these models to decide abnormal patternand to schedule maintenance. Finally, for other components or equipment which is not covered by predictive approach, we adoptedpreventive maintenance approach. To show feasibility we developed an integrated maintenance support system in LabView Watchdog Agent and SQL Server environment and validated our proposed methodology with experimental data.

• 접착 및 계면
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• 제12권1호
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• pp.34-42
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• 2011

자동차용 도장시스템으로 새롭게 대두되고 있는 roll coating process는 비친환경적이면서도 생산성이 떨어지는 기존의 습식도장공정을 완전 대체할 수 있는 기술로 알려져 있다. Pre-painted 강판 시스템에서 도막 유연성 및 강도 등의 구현을 위하여 경화거동뿐만 아니라 내식성 및 성형가공성, 유변학적 거동 등의 평가가 매우 중요하다. 본 연구에서는 pre-painted system에 적용하기 위하여 polyester 수지를 수산화기 및 분자량 변성을 통하여 합성한 후, 경화거동 및 딥드로잉, 인장력, 유변특성 등을 평가하였다. 40 (mg KOH-/mol)정도의 수산화기를 갖는 N-0375-40 system이 유연성 및 도막강도, 경화거동 등의 가장 우수한 물성을 나타내었다.

• 한국정보과학회논문지:시스템및이론
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• 제31권8호
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• pp.453-464
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• 2004

In order to solve the well-known drawback of reduced flexibility that is associate with ASIC implementations, this paper proposes a novel arithmetic unit over GF(2$^{m}$ ) for field programmable gate arrays (FPGAs) implementations of elliptic curve cryptographic processor. The proposed arithmetic unit is based on the binary extended GCD algorithm and the MSB-first multiplication scheme, and designed as systolic architecture to remove global signals broadcasting. The proposed architecture can perform both division and multiplication in GF(2$^{m}$ ). In other word, when input data come in continuously, it produces division results at a rate of one per m clock cycles after an initial delay of 5m-2 in division mode and multiplication results at a rate of one per m clock cycles after an initial delay of 3m in multiplication mode respectively. Analysis shows that while previously proposed dividers have area complexity of Ο(m$^2$) or Ο(mㆍ(log$_2$$^{m}$ )), the Proposed architecture has area complexity of Ο(m), In addition, the proposed architecture has significantly less computational delay time compared with the divider which has area complexity of Ο(mㆍ(log$_2$$^{m}$ )). FPGA implementation results of the proposed arithmetic unit, in which Altera's EP2A70F1508C-7 was used as the target device, show that it ran at maximum 121MHz and utilized 52% of the chip area in GF(2$^{571}$ ). Therefore, when elliptic curve cryptographic processor is implemented on FPGAs, the proposed arithmetic unit is well suited for both division and multiplication circuit.

• 한국구조물진단유지관리공학회 논문집
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• 제21권3호
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• pp.86-92
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• 2017

장스팬 구조물은 사용하중 하에서 바닥진동 문제가 발생할 가능성이 크다. 따라서 구조물 바닥판의 진동성능을 향상시키기 위한 가장 일반적인 방법은 슬래브의 두께를 증가시키는 것이지만 기존의 구조시스템에서 슬래브의 두께를 증가시키면 슬래브 자중의 증가로 건축물 전체의 효율성이 떨어지게 되는 문제점이 있다. 따라서 슬래브의 두께를 증가시키면서도 자중은 크게 증가하지 않는 바닥판 시스템으로 중공슬래브에 관한 관심이 커지고 있는 상황이다. 이에 부력방지능력 및 시공성 향상을 위하여 데크플레이트와 경량성형재를 결합한 형태의 중공슬래브를 개발하였고, 이 중공슬래브를 적용한 실물(mock-up) 건축물에 대한 사용성 검증을 위한 진동성능 평가를 수행하였다. 측정된 결과값을 분석한 결과, 일본건축학회의 "건축물의 진동에 관한 거주 성능 평가지침"에 의하면 1등급인 거실, 침실에 사용해도 될 수준으로 평가되었다.

• 산업경영시스템학회지
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• 제38권4호
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• pp.177-183
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• 2015

Incremental sheet metal forming is a manufacturing process to produce thin parts using sheet metals by a series of small incremental deformation. The process rarely needs dedicated dies and molds, thus, preparation time for the process is relatively short as to be compared to conventional metal forming. Spring back in sheet metal working is very common, which causes critical errors in dimensions. Incremental sheet metal forming is not fully investigated yet. Hence, incremental sheet metal forming frequently produces inaccurate parts. This paper proposes a method to minimize dimensional errors to improve shape accuracy of products manufactured by incremental forming. This study conducts experiments using an exclusive incremental forming machine and the material for these experiments are sheets of aluminum AL1015. This research defines a process parameter and selects a few factors for the experiments. The parameters employed in this paper are tool feed rate, tool diameter, step depth, material thickness, forming method, dies applied, and tool path method. In addition, their levels for each factor are determined. The plan of the experiments is designed using orthogonal array $L_8$ ($2^7$) which requires minimum number of experiments. Based on the measurements, dimensional errors are collected both on the tool contacted surfaces and on the non-contacted surfaces. The distances between the formed surfaces and the CAD models are scanned and recorded using a commercial software product. These collected data are statistically analyzed and ANOVAs (analysis of variances) are drawn up. From the ANOVAs, this paper concludes that the process parameters of tool diameter, forming depth, and forming method are the significant factors to reduce the errors on the tool contacted surface. On the other hand, the experimental factors of forming method and dies applied are the significant factors on the non-contacted surface. However, the negative forming method always produces better accuracy than the positive forming method.

• 산업경영시스템학회지
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• 제42권3호
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• pp.176-183
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• 2019

The environmental changes in the Korean cosmetic medical service industry in the $21^{st}$ century are forming intense competition among medical institutions due to the quantitative expansion of its market. For stable growth of the cosmetic medical service industry, continuous quality improvement is necessary based on empirical research on the quality of cosmetic medical services rather than external expansion. The purpose of this study is to classify the quality attributes of cosmetic medical service using Kano model and to derive the degree of satisfaction and dissatisfaction of each quality attributes through Customer Satisfaction Coefficient (CSC). Through this, the study identified strategic priorities and suggested specific step-by-step approaches and quality improvement priorities that can increase customer satisfaction using the Potential Customer Satisfaction Improvement Index (PCSI Index). Based on SERVPERF, this study used measurement tools consisting of five dimensions : tangibles, reliability, responsiveness, assurance, and empathy. In addition, it was used of measurement items reconstructed into positive, negative, and satisfaction questions for Kano model analysis, CSC analysis, and PCSI Index analysis. A total of 300 medical consumers who experienced cosmetic medical services for the past one year in medical institutions such as plastic surgery and dermatology were collected with convenient sampling. As a result, urgent items for improving the quality of service using the PCSI Index, 'Consideration for customer benefits' in empathy category was followed by 'Immediate help' and 'Sincere response' in responsiveness category, and 'Understanding customer needs' in empathy category, respectively. That is, it is required to improve human service quality attributes such as empathy and responsiveness rather than physical service quality attributes. This study contributes practically in that it provides specific and discriminatory approaches to improve customer satisfaction on cosmetic medical service quality and suggests improvement priorities.

• 한국분말재료학회지
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• 제31권1호
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• pp.50-56
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• 2024

We report the effect of plastic deformation on the thermoelectric properties of n-type Bi₂Te_2.5Se_0.5 compounds. N-type Bi₂Te_2.5Se_0.5 powders are synthesized by an oxide-reduction process and consolidated via spark-plasma sintering. To explore the effect of plastic deformation on the thermoelectric properties, the sintered bodies are subjected to uniaxial pressure to induce a controlled amount of compressive strains (-0.2, -0.3, and -0.4). The shaping temperature is set using a thermochemical analyzer, and the plastic deformation effect is assessed without altering the material composition through differential scanning calorimetry. This strategy is crucial because the conventional hot-forging process can often lead to alterations in material composition due to the high volatility of chalcogen elements. With increasing compressive strain, the (00l) planes become aligned in the direction perpendicular to the pressure axis. Furthermore, an increase in the carrier concentration is observed upon compressive plastic deformation, i.e., the donor-like effect of the plastic deformation in n-type Bi₂Te_2.5Se_0.5 compounds. Owing to the increased electrical conductivity through the preferred orientation and the donor-like effect, an improved ZT is achieved in n-type Bi₂Te_2.5Se_0.5 through the compressive-forming process.

• 터널과지하공간
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• 제26권5호
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• pp.396-408
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• 2016

암석파괴역학은 토목공학과 암반공학의 다양한 분야에서 널리 적용되는 학문이다. 그러나 대부분의 암반 공학 문제에서 mode II 거동이 우세함에도 불구하고 관련 연구는 mode I 거동에 대한 것이 대부분이다. 현재 mode I의 경우 4개, mode II 파괴인성의 경우 단 한 개의 ISRM 표준시험법이 있다. 본 연구에서 제안하는 새로운 시험법은 문헌조사를 통해서 필요조건으로 구속압 가능 여부, 노치성형의 용이성, 기존 시험장비의 활용, 단순한 시험절차를 정하고 이에 부합하도록 개발하였으며 SCC(Short Core in Compression)로 이름을 정하였다. Mode II 파괴인성 계산에 필요한 응력확대계수 계산식을 3차원 수치해석을 통해 선하중과 분포하중 조건에 대해서 구하였고 노치성형을 위한 지그도 제작하였다. 개발된 시험법을 MTS 시스템을 사용하여 화강암에 적용하였으며 가압속도는 0.002 mm/s로 하였다. 시험 결과 $2.33MPa{\sqrt{m}}$의 mode II 파괴인성을 얻었다. 동일한 화강암 블록에서 확보한 시험편에 대하여 간접인장시험으로 구한 mode I 파괴인성은 $1.12MPa{\sqrt{m}}$였다. 따라서 $K_{IIC}/K_{IC}=2.08$로 mode II 파괴인성이 mode I보다 크게 나타났다. 또한 비교적 매끄러운 파괴면과 암분의 생성을 통하여 SCC 시험법이 mode II 거동을 잘 표현함을 확인하였다. 따라서 제안된 SCC 시험법은 암석의 mode II 파괴인성을 결정하는 데 사용할 수 있을 것으로 판단된다.