• 대한물리의학회지
• /
• 제7권4호
• /
• pp.459-469
• /
• 2012

PURPOSE: The purpose of the present study was to examine changes caused by asymmetric bag carrying methods to carry the bag with one shoulder only to plantar pressure during walking. METHODS: Twenty three normal adults without any gait problem participated in the present study. Experimental conditions used consisted of walking without carrying any bag(condition 1), walking wearing a bag on both shouders (condition 2), and walking wearing a bag on the right shoulder(condition 3) and the weight of the bag was set to 15% of each subject's body weight. All the subjects were instructed to participate in all experiments under these three conditions and plantar pressures were measured from the subjects' right and left feet using an F-scan system while the subjects were walking under the three conditions. To analyze the measured plantar pressure, the sole was divided into seven areas (Hallux, Toe, Met1, Met23, Met45, Mid foot and Heel) and maximum plantar pressures in individual areas were measured. RESULTS: The results of measurement of plantar pressures under three walking conditions did not show significant changes in any areas of the left and right feet except for the mid foot area of the right food. The asymmetry between the left and right feet was examined and the results showed significant differences only in area Met23 under condition 2 and did not show significant differences in any other areas. CONCLUSION: On comprehensively considering the results of the present study, it could be seen that asymmetric bag carrying did not have large effects on changes in plantar pressure during walking compared to symmetric carrying. The reason for this is considered to be posture adjusting mechanisms against load positions.

• 한국산림과학회지
• /
• 제87권4호
• /
• pp.590-600
• /
• 1998

본 연구에서는 규범적 접근방법을 이용하여 무등산 도립공원의 주요 시설물에 대한 평가기준을 설정하고, 설정된 평가기준을 토대로 공원의 현 시설물 관리상태를 평가하였으며, 여기에서 발견된 문제점을 해결하기 위한 개선방안을 제시하였다. 데이터는 1996년 8월 중 무등산 도립공원에서 현지설문조사와 우편설문조사에 의하여 수집되었으며, 총 1,173명의 조사대상자 중 519명(44.2%)이 본 연구의 분석에 이용되었다. 결과에 따르면, 선정된 5개 지표항목 중 '쓰레기통 충분여부'와 '등산로 안내시설 충분여부'를 제외한 3개 지표항목(화장실 충분여부, 화장실 청결상태, 대중교통수단을 이용하기 위하여 기다려야 하는 시간)에서 현 상황이 명가기준보다 불량한 것으로 나타났다. '등산로 안내시설 충분여부'에 대한 현 상황은 평가기준과 동일하였다. 문제점이 있는 것으로 밝혀진 지표항목에 대해서는 이를 개선하기 위한 관리대안을 제시하였으며, 이러한 자료들이 공원 시설물관리를 위하여 어떻게 이용될 수 있을 것인가를 소개하였다.

• Steel and Composite Structures
• /
• 제20권3호
• /
• pp.623-649
• /
• 2016

Most of the early studies on plates vibration are focused on two-dimensional theories, these theories reduce the dimensions of problems from three to two by introducing some assumptions in mathematical modeling leading to simpler expressions and derivation of solutions. However, these simplifications inherently bring errors and therefore may lead to unreliable results for relatively thick plates. The main objective of this research paper is to present 3-D elasticity solution for free vibration analysis of continuously graded carbon nanotube-reinforced (CGCNTR) rectangular plates resting on two-parameter elastic foundations. The volume fractions of oriented, straight single-walled carbon nanotubes (SWCNTs) are assumed to be graded in the thickness direction. In this study, an equivalent continuum model based on the Eshelby-Mori-Tanaka approach is employed to estimate the effective constitutive law of the elastic isotropic medium (matrix) with oriented, straight carbon nanotubes (CNTs). The proposed rectangular plates have two opposite edges simply supported, while all possible combinations of free, simply supported and clamped boundary conditions are applied to the other two edges. The formulations are based on the three-dimensional elasticity theory. A semi-analytical approach composed of differential quadrature method (DQM) and series solution is adopted to solve the equations of motion. The fast rate of convergence of the method is demonstrated and comparison studies are carried out to establish its very high accuracy and versatility. The 2-D differential quadrature method as an efficient and accurate numerical tool is used to discretize the governing equations and to implement the boundary conditions. The convergence of the method is demonstrated and to validate the results, comparisons are made between the present results and results reported by well-known references for special cases treated before, have confirmed accuracy and efficiency of the present approach. The novelty of the present work is to exploit Eshelby-Mori-Tanaka approach in order to reveal the impacts of the volume fractions of oriented CNTs, different CNTs distributions, various coefficients of foundation and different combinations of free, simply supported and clamped boundary conditions on the vibrational characteristics of CGCNTR rectangular plates. The new results can be used as benchmark solutions for future researches.

• Structural Engineering and Mechanics
• /
• 제62권5호
• /
• pp.519-535
• /
• 2017

In this article, static analysis of a magneto-electro-elastic (MEE) beam subjected to various thermal loading and boundary conditions has been investigated. Influence of pyroeffects (pyroelectric and pyromagnetic) on the direct quantities (displacements and the potentials) of the MEE beam under different boundary conditions is studied. The finite element (FE) formulation of the MEE beam is developed using the total potential energy principle and the constitutive equations of the MEE material taking into account the coupling between elastic, electric, magnetic and thermal properties. Using the Maxwell electrostatic and electromagnetic relations, variation of stresses, displacements, electric and magnetic potentials along the length of the MEE beam are investigated. Effect of volume fractions, aspect ratio and boundary conditions on the direct quantities in thermal environment has been determined. The present investigation may be useful in design and analysis of magnetoelectroelastic smart structures and sensor applications.

• KIEAE Journal
• /
• 제3권2호
• /
• pp.51-58
• /
• 2003

The purpose of this study is to present rational methods of multi-criteria optimization of the shape of energy saving buildings. The object is to determine the optimum dimension of the shape of a building, based on the following criteria: minimum building costs (including the cost of materials and construction) and yearly heating costs. Mathematical model described heat losses and gains in a building during the heating season. It takes into consideration heat losses through wall, roof, floor and windows. Particular attention was paid to have a more detailed description of heat gains due to solar radiation. On the assumption that shape of building is rectangle in order to solve the problem, the proportions of wall length and building height are determined by using non-linear programing methods(Kuhn-Tucker Conditions). The results constitute information for designers on the optimum proportions of wall lengths, height, and the ratios of window to wall areas for energy saving buildings.

• 한국병원경영학회지
• /
• 제14권2호
• /
• pp.41-59
• /
• 2009

Modern job seekers often visit recruitment web-site for employment. Recruiting on the Internet is one of the fastest-growing recruitment methods. But there was not research about Internet recruitment in health care labor market. The purpose of this study is to research the actual conditions of hospital recruitment by using internet homepage of Korea College of Hospital Administrators(KCHA). Data were collected from 399 iob posting and job seeker's interest in Internet homepage of KCHA. This study analyzed the research model using data mining method. This study shows that the frequency of job posting and job seeker's interest depend upon a season. The result of this study indicates that there is necessity to present the various and specific employment conditions. As the recruitment becomes job seeker-centered in other industry labor market, it is also recommended in the health labor market. Therefore a job posting should provide a salary range and emphasize competitive benefits for job seekers in the health labor market.

• 대한인간공학회지
• /
• 제15권1호
• /
• pp.91-103
• /
• 1996

For determining thermal comfort properties of work suit in an atomic power plant, three different coverall ensembles (PVE, PET/Rayon, PP Nonwoven) were selected and the resistance to dry and evaporative heat transfer were measured for each ensemble by using a sweating thermal manikin. Also, PMV (Predicted Mean Vote) and PPD(Predicted Percentage of Dissatisfied) indices were predicted according to ISO 7730. As a result, ideal environmental conditions in an atomic power plant were suggested to make workers feel thermally comfortable. In addition, ideal intrinsic insulation values of coverall ensembles as a work suit under the present environmental conditions in the at6omic power plant were provided. The information given in this paper can be used to control environmental conditions in the atomic power plant thermally comfortable and to select a proper work suit for providing thermal comfort to the workers.

• 한국수학교육학회지시리즈B:순수및응용수학
• /
• 제15권4호
• /
• pp.365-375
• /
• 2008

We present a new theorem for the semilocal convergence of Newton's method to a locally unique solution of an equation in a Banach space setting. Under a gamma-type condition we show that we can extend the applicability of Newton's method given in [12]. We also provide a comparative study between results using the classical Newton-Kantorovich conditions ([6], [7], [10]), and the ones using the gamma-type conditions ([12], [13]). Numerical examples are also provided.

• 신재생에너지
• /
• 제3권3호
• /
• pp.54-62
• /
• 2007

The present paper describes the scale effect correction methods for scaled NREL Phase VI wind turbines by using CFD[computational fluid dynamics). For the corrections of wind turbine scale effect, various researches on the helicopter rotor scale effect were investigated and the feasibility study of the methods was performed to correct wind turbine scale effect. The present paper also introduces scale effect correction methods based on two dimensional lift slope. In order to test the present method, performance analyses of NREL Phase VI wind turbines under various scale conditions were carried out and new correction method was applied. Granting that the new correction method is valid only above Reynolds No. 100,000, it showed reasonable agreement between model and full scale wind turbines in the linear torque region.

• Safety and Health at Work
• /
• 제8권4호
• /
• pp.378-385
• /
• 2017

Background: The present rapid shift of industrialization from developed to developing countries requires developing countries to understand issues related to work organization, management, and working conditions. There are many factors slackening production, of which working conditions is part. A complete inquiry into the workers' working conditions can enable managements to reduce risks in the workplaces and improve productivity. Understanding and awareness of the benefits of workplace research and a probe into the working conditions in the Ugandan apparel assembly plants are urgently required. Methods: A total of 103 (70 women and 33 men) workers from five different plants were interviewed. Together with the top management of various plants, questionnaires about the workers' opinions of their physical working conditions were prepared. Data was collected using two methods: (1) questionnaire; and (2) observation of the workers during their work. Results: The results indicated that poor plant working conditions were mainly contributed by the workers' social factors and the management policies. Conclusion: The government, together with the management, should work to improve the working conditions in the apparel assembly plants, as it greatly affects both.