• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.595-596
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• 2006

The flexible organic thin film transistor (OTFT) array to use as a switching device for an organic light emitting diode (OLED) was designed and fabricated in the microcontact printing and low-temperature processes. The gate, source, and drain electrode patterns of OTFT were fabricated by microcontact printing which is high-resolution lithography technology using polydimethylsiloxane(PDMS) stamp. The OTFT array with dielectric layer and organic active semiconductor layers formed at room temperature or at a temperature tower than $40^{\circ}C$. The microcontact printing process using SAM(self-assembled monolayer) and PDMS stamp made it possible to fabricate OTFT arrays with channel lengths down to even nano size, and reduced the procedure by 10 steps compared with photolithography. Since the process was done in low temperature, there was no pattern transformation and bending problem appeared. It was possible to increase close packing of molecules by SAM, to improve electric field mobility, to decrease contact resistance, and to reduce threshold voltage by using a big dielecric.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.7
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• pp.585-590
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• 2017

Vehicle behavior is determined by forces and a torques generated at the ground contact surface of the tire. Various tire models are used to calculate the forces and torques acting on the tire. The brush model calculates the forces and torques with fewer coefficients than other tire models. However, owing to fewer degrees of freedom in calculating the forces, this model has limitations in precisely expressing measured data. In this study, this problem was addressed by adding the least parameters to the friction coefficient and tire properties of the brush model, and the proposed model was validated.

• Korean Medical Education Review
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• v.15 no.3
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• pp.120-124
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• 2013

The clinical clerkship focuses students on developing their ability to perform comprehensive diagnosis and management of patients with common undifferentiated problems by the integration of knowledge and clinical reasoning. Therefore, the clerkship evaluation system should assess their actual problem solving and professional behavior. However, concern remains that clerkship evaluations are imprecise and highly variable. This review is designed to provide faculty members with concepts, options, and a methodology to actively teach and evaluate the clinical clerkship, as well as offer encouragement and inspiration to medical students. We reviewed past and current clinical clerkship evaluations and discuss several tips to improve clinical excellence such as continuity, transparency of the evaluation process, a faculty development program, practical examination of clinical skills, implementation of a checklist for recording exposure and skills, providing prompt and constructive feedback to students, self-evaluation of professional performance, varying multi-faceted assessment combinations, being outpatient clinic-centered, and having dedicated faculty members who give students one-on-one contact with a preceptor.

• Journal of Korea Foundry Society
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• v.23 no.5
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• pp.244-250
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• 2003

The aim of this study is fabricating of composite filler metal (CFM) by a combination of selective laser sintering (SLS) of stainless steel powders (RapidSteel $2.0^{TM}$ and liquid phase infiltration of Ag-28 wt.%Cu alloy. Porous stainless steel body with inter-connected pore channels was fabricated by SLS, binder decomposing and densification processes. By the direct contact infiltration, the narrow inter-particle channels of the porous body were completely filled with the Ag-28 wt.%Cu alloy infiltrant. During infiltration, the dissolved elements of Fe, Ni and Cr from the porous body were solved into copper solid solution phases, which consist of eutectic structure of composite metal matrix. The S10C/CFM/S10C joints, which have narrow clearance gaps between them up to 10 micrometers, were joined successfully by self-feeding of filler metal from the matrix of CFM. The CFM kept its original thickness and microstructure after brazing. The tensile strength of brazed specimen was higher than 30 kgf/$mm^2$ and showed a typical ductile fracture mode in the CFM.

• International Journal of Human Ecology
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• v.9 no.2
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• pp.117-126
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• 2008

The study identifies gender stereotypes, examines the level of women's economic empowerment at the household level and explores the influence of factors on it. Data were collected from 159 randomly selected farm women using both qualitative and quantitative survey methods between January and March 2007 from three villages of the Mymensingh District of Bangladesh. Four key informants (2 local leaders and 2 development personnel) were questioned to elicit views in the light of boosting women's empowerment. Five constructs of empowerment covering 30 indicators were aggregated together to develop a cumulative economic empowerment index (CEEI) to obtain multidimensional views of women's empowerment. The findings show that there were some prejudices against women in allocating divisions of labour and access to education, food, property, decision-making and institutions. The distribution of the CEEI demonstrates that the majority of the respondents (86%) had a low to moderate level of empowerment. A multiple regression analysis showed positive significant effects of education, training, media contact and freedom of mobility on women's CEEI, while domestic abuse restrained it. It is concluded that interventions by development agencies in co-ordination with the local community was necessary to attain women's self-reliance in the study area. Development actors can undertake some core strategies to enhance women's level of awarencess, knowledge, skills, and productive resources through providing training, loans, and information. To change traditional beliefs, it is important to create awareness of various gender issues amongst rural people through different methods and media.

• Transactions of the Korean Society of Mechanical Engineers
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• v.14 no.3
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• pp.594-602
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• 1990

A computer-aided design system of involute cylindrical gears(spur and helical gears) for power transmission is developed, in which the volume of a gear unit is minimized with satisfying various design constraints. As the design constraints, bending strength and pitting resistance of AGMA 218.01, scoring of Dudley's flash temperature, contact ratio, and involute interference of pinion are considered and effective factors for strength calculation(life, reliability, hardness ratio, load distribution, velocity, etc.) are also included. This complicated nonlinear optimization problem is solved by using ALM(Augmented-Lagrange-Multiplier) method with self scaling BFGS(Broydon-Fletcher-Goldfarb-Shanno) method employed for unconstrained optimization programming. This design method can be easily applied to designing power transmission gear unit in the machines of various kinds. It is expected for the proposed method to be a contribution for an automated design of gear unit towards weight minimization, miniaturization and high strength of gear unit.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.601-601
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• 2013

Superhydrophobic W18O49 nanowire (NW) arrays were synthesizedusing a thermal evaporation and surface chemistry modification methods by self-assembled monolayer (SAM). As-prepared non-wetting W18O49 NWs surface shows water contact angle of $163.2^{\circ}$ and has reliable stability in underwater conditions. Hence the superhydrophobic W18O49 NWs surface exhibits silvery surface by total reflection of water layer and air interlayer. The stability analysus of underwater superhydrophobicity of W18O49 NWs arrays was conducted by changing hydrostatic pressure and surface energy of W18O49 NWs arrays. The stability of superhydrophobicity in underwater conditions decreased exponentially as hydrostatic pressure applied to the substrates increased3. In addition, as surface energy decreased, the underwater stability of superhydrophobic surface increased sharply. Specifically, sueprhydrophobic stability increased exponentially as surface energy of W18O49 NWs arrays was decreased. Based on these results, the models for explaining tendencies of superhydrophobic stability underwater resulting from hydrostatic pressure and surface energy were designed. The combination of fugacity and Laplace pressure explained this exponential decay of stability according to hydrostatic pressure and surface energy. This study on fabrication and modeling of underwater stability of superhydrophobic W18O49 NW arrays will help in designing highly stable superhydrophobic surfaces and broadening fields of superhydrophobic applications even submerged underwater.

• Journal of Computational Design and Engineering
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• v.3 no.2
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• pp.151-160
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• 2016

Cutter-workpiece engagement (CWE) is the instantaneous contact geometry between the cutter and the in-process workpiece during machining. It plays an important role in machining process simulation and directly affects the calculation of the predicted cutting forces and torques. The difficulty and challenge of CWE determination come from the complexity due to the changing geometry of in-process workpiece and the curved tool path of cutter movement, especially for multi-axis milling. This paper presents a new method to determine the CWE for general milling processes. To fulfill the requirement of generality, which means for any cutter type, any in-process workpiece shape, and any tool path even with self-intersections, all the associated geometries are to be modeled as triangle meshes. The involved triangle-to-triangle intersection calculations are carried out by an effective method in order to realize the multiple subtraction Boolean operations between the tool and the workpiece mesh models and to determine the CWE. The presented method has been validated by a series of case studies of increasing machining complexity to demonstrate its applicability to general milling processes.

• Korean Journal of Community Nutrition
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• v.9 no.5
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• pp.597-605
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• 2004

The purpose of the study was to investigate relationships among food safety training, knowledge, and practices of school food service employees. A questionnaire that identified employees' food safety training experience, knowledge, and practices was developed based on a review of literature. A total of 341 Korean school food service employees participated in the survey; the final usable responses were 293 (a response rate: 86%). Statistical analyses were conducted using SPSS for Windows (version 10). Most of the respondents (> 86%) took training sessions on 'proper hand washing' and 'proper food storage temperatures', whereas less than 60% had training on 'monitoring procedures and corrective actions at critical control points'. The mean score of their food safety knowledge was 8.02 out of 11. The majority of the employees knew correctly 'potentially hazardous foods (93.2%)' and 'diseases and symptoms with which they are excluded from working (87.0%)'; less than 50% chose a correct answer for 'sanitizing food contact surfaces.' A chi-square analysis revealed that the employees' actual knowledge did not differ significantly by whether they had food safety training (at the level of a =0.01), except one topic 'diseases and symptoms with which they are excluded from working.' Their self-reported practice scores were rated as 2.98 - 3.39 based on a 5-point Likert-type scale (1-not at all, 5-always). Employees' food safety training should be conducted continuously and repetitively to improve the effectiveness of the training.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.5 no.2
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• pp.269-278
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• 2001

Most of education sites which are related to practical computer lecture are almost learning and testing based on character-contents. In this thesis, commercial high school needs the use of new application programs which appear quickly. So as teacher and students can contact with each other in classroom, we implemented self-teaming which has text, visual and auditory function with the use of animation technology. Not only quantity testing which has been used for the purpose of selection and arrangement, but also we designed and implemented quality testing which consider the level and individuality of student.