• Polymer(Korea)
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• v.36 no.4
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• pp.507-512
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• 2012

Thin (~650 nm) and ultrathin (~50 nm) films of neat PMMA and PMMA containing 5 wt% of methacryl-polyhedral oligomeric silsesquioxane were prepared in this work. The effects of film thickness and POSS on glass transition temperature ($T_g$) and isothermal physical aging were investigated by means of differential scanning calorimetry (DSC). $T_g$ depression was observed as film thickness was decreased and Ma-POSS molecules were incorporated. Enthalpy relaxation (${\Delta}H_{Relax}$) due to the isothermal physical aging was reduced by ultra-thin film thickness and the addition of Ma-POSS. KWW (Kohlrausch-Williams-Watts) equation was used to fit ${\Delta}H_{Relax}$ vs. aging time data providing the fitting parameters; maximum enthalpy recovery (${\Delta}H_{\infty}$), relaxation time (${\tau}$) and non-exponentiality parameter (${\beta}$).

• The Korean Journal of Pain
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• v.33 no.3
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• pp.245-257
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• 2020

Background: Musculoskeletal pain is associated with obesity; however, information on factors associated with pain in adults with obesity and severe obesity is limited. The purpose of this study was to assess the prevalence of musculoskeletal pain by site and intensity of pain and associated factors in individuals with severe obesity (body mass index ≥ 35.0 kg/㎡). Methods: Baseline data from the DieTBra Trial study evaluating pain symptoms in nine body regions over the last seven days using the Nordic Questionnaire on Musculoskeletal Symptoms and Numerical Pain Scale. The variables analyzed using multiple Poisson regression with hierarchical analysis were: sociodemographic, lifestyle, food consumption, clinical, and anthropometric, and the outcome was moderate and intense pain. Results: In 150 participants, there was a high prevalence of ankle and foot pain (68.7%), lower back pain (62.7%), pain in the knees (53.3%) and upper back pain (52.0%), with a predominance of intense pain. Factors associated with pain according to specific sites were: type 2 diabetes with hand/wrist pain; sedentary time with hip pain; insomnia with pain in the hip and knee; edema in the lower limbs with pain in the lower back and ankles/feet; degree of obesity with ankle/foot pain; and percentage of total fat with ankle/foot pain. Conclusions: There was a high prevalence of pain and intense pain in individuals with severe obesity and an association with clinical variables, the degree of obesity, and sedentary lifestyle.

• ETRI Journal
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• v.29 no.3
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• pp.281-291
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• 2007

Wearable computers consisting of various small devices such as smart phones, digital cameras, MP3 players and specialized I/O devices in personal area networks will play an important role in future ubiquitous computing. In this environment, accessing user data is quite complex due to the dynamic and heterogeneous characteristics of the underlying networks. Moreover, since the amount of user data increases rapidly, automatic data backup management is also critical. To overcome these challenges, several studies have been conducted including our previously proposed file service system, PosCFS, which could be adapted to the requirements with a virtualization technique allowing per-user global namespace for managing and accessing data stored on physical storage spaces detected in PAN. In this paper, we present a smart file service framework, PosCFS+ which is an improved and extended version of our previous work. Performance improvement is made possible by redesigning the metadata management scheme based on database and keywords rather than ontology. In addition, the automatic data replication management is newly designed based on the OSD protocol.

• Journal of the Korean earth science society
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• v.29 no.5
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• pp.375-385
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• 2008

The relationship between two interannual climate variabilities and the frequency of tropical cyclone (TC) that landed over the Korean Peninsula (KP) has investigated for the period of 1951-2004. In the analysis of the relationship between KP-landfall TC frequency and the ENSO phase, most TCs of C-14 (TCs that do not pass through mainland China before landing the KP) and C-23 (TCs that pass through mainland China before landing the KP) tended to more land in the warm phase than normal and cold phases. However, TC intensity at landfall was stronger in the cold and normal phases. In the analysis of the relationship between KP-landfall TC frequency and Arctic Oscillation (AO) phase, the TCs of C-14 tended to more land in the positive (POS) phase of AO and the negative (NEG) phase of AO for C-23. It was found that AO index was negatively correlated with the Ni$\tilde{n}$o-3.4 index. And then the TCs of C-14 landed more frequently over the KP in the AO POS - Ni$\tilde{n}$o-3.4 NEG phases and in the AO NEG - Ni$\tilde{n}$o-3.4 POS phases for the TCs of C-23.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1064_1065
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• 2009

PV (Photovoltaic) power generation system has been widely studied as a clean and renewable power source. Tracking the MPP (maximum power point) of a PV array is usually an essential part of a PV system. This paper describes POS (Photovoltaic Output Sensorless) MPPT method and optimization technique of its operational characteristics for grid-connected PV generation system. A DC-DC converter has been used to step-up the PV voltage and DC-AC converter has been used for connecting the system to the grid. Optimization technique has been implemented to optimize the current and voltage controller gain parameters and duty ratio increment of DC-DC converter. Simulation results reveal that the proposed control has better response.

• Computers and Concrete
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• v.17 no.1
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• pp.141-156
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• 2016

The search for new structural systems capable of associating performance and safety requires deeper knowledge regarding the mechanical behavior of structures subject to different loading conditions. The Strut-and-Tie Model is commonly used to structurally designing some reinforced concrete elements and for the regions where geometrical modifications and stress concentrations are observed, called "regions D". This method allows a better structural behavior representation for strength mechanisms in the concrete structures. Nonetheless, the topological model choice depends on the designer's experience regarding compatibility between internal flux of loads, geometry and boundary/initial conditions. Thus, there is some difficulty in its applications, once the model conception presents some uncertainty. In this context, the present work aims to apply the Strut-and-Tie Model to nonlinear structural elements together with a topological optimization method. The topological optimization method adopted considers the progressive stiffness reduction of finite elements with low stress values. The analyses performed could help the structural designer to better understand structural conceptions, guaranteeing the safety and the reliability in the solution of complex problems involving structural concrete.

• Structural Engineering and Mechanics
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• v.28 no.5
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• pp.603-633
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• 2008

A four-node plate finite element for the analysis of laminated composites which is developed using strain gradient notation is presented. The element is based on a first-order shear deformation theory and on the equivalent lamina assumption. Strains and stresses can be calculated at different points through the thickness of the plate. They are averaged values due to the equivalent lamina assumption. A shear correction factor is used as the transverse shear strain is taken to be constant over the plate thickness while its actual variation is parabolic. Strain gradient notation, which is physically interpretable, allows for the detailed a-priori analysis of the finite element model. The polynomial expansions are inspected and spurious terms responsible for modeling errors are identified in the shear strains polynomial expansions. The element is corrected by simply removing the spurious terms from the shear strains expansions. The element is implemented into a FORTRAN finite element code in two versions; namely, with and without spurious terms. Results are compared to show the effects of the spurious terms on the solutions. It is also shown that a refined mesh composed of corrected elements provides solutions which approximate very well the analytical solutions, validating the procedure.

• Proceedings of the Korean Society of Computer Information Conference
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• 2014.01a
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• pp.131-133
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• 2014

본 논문에서는 서비스업의 매장에 설치된 POS(Point of sale) 또는 Smart device를 이용하여 빈 방 또는 빈 테이블 등의 서비스 가능 공간 수에 따라 실시간으로 가격이 변동되는 시스템을 제안한다. 고객 입장에서는 보다 싼 가격으로 서비스를 이용할 수 있으며, 매장주 입장에서는 한산한 시간에 경쟁력 있는 가격으로 고객을 유치할 수 있도록 도움을 준다. 고객은 애플리케이션에 접속하여 위치기반서비스를 통해 이용하고자하는 서비스 매장을 선택하여 실시간으로 변동되는 서비스 가격을 확인할 수 있으며, 예약 및 결제를 한 후, 일정 시간 내에 해당 매장에 가서 서비스를 이용할 수 있다. 매장주는 POS 또는 Smart device를 통해 자동 또는 수동으로 서비스 가격을 변동시킬 수 있다.

• Korean Medical Education Review
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• v.15 no.1
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• pp.1-8
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• 2013

Outcome-Based education (OBE) is reviewed from the institutional perspective. The demand for and international trends in OBE are briefly examined and several term related to OBE, especially educational objective and program outcomes (POs), are introduced. It is stressed that systems for continuous quality improvement and quality assurance should be established to ensure the maintenance of the OBE system. Because the criteria for accreditation contain a criterion regarding the quality assurance related to program outcomes, several critical issues are considered regarding the POs themselves and the reduction of the POs. The core value of OBE is not only to provide appropriate education services to students to prepare them with the minimum skills and abilities for advancing their professional service, but also to guarantee the quality of graduates. In addition, the educational program should be continuously improved by employing the evaluation results acquired during the operation of the OBE systems. It is certain that an OBE system is one important aspect of student-centered education.

• Asia-Pacific Journal of Business
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• v.15 no.1
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• pp.159-177
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• 2024

Purpose - The purpose of this study is to reveal the effect of a High Performance Work System(HWPS) on research performance. In addition, this study examines the mediation effect of Innovation Commitment(IC) and the moderated mediation effect of Perceived Organizational Support(POS), and seeks to reveal the antecedents and boundary variables that affect research performance. Design/methodology/approach - The level of analysis is at the individual level. A survey was collected from researchers at government-funded research institutes in the Daejeon and Sejong areas. 265 questionnaires were used in the final statistical analysis. Confirmatory factor analysis was performed using the AMOS 21. Correlation analysis, regression analysis, and bootstrapping by Process Macro were performed using the SPSS 19. Findings - As a result of the study, HWPS has a positive effect on IC, and IC has a positive effect on research performance. Through this results, it was found that IC mediates the relationship between the HPWS and research performance. In addition, POS positively moderated the mediating effect of HPWS on research performance through IC. Research implications or Originality - First, IC can be increased through a HPWS. Second, the effect of the HWPS on individual research performance through IC provides implications that the HWPS can be effectively applied not only to general companies but also to research organizations. Third, the boundary effect of POS was revealed. Fourth, research performance was measured through objective quantitative indicators rather than subjective.