• Steel and Composite Structures
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• v.20 no.3
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• pp.693-718
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• 2016

This paper presents a finite element procedure based on Bridging multi-scale method (BMM) in order to incorporate the effect of local/cross-sectional deformations (e.g., flange local buckling and web crippling) on the global behaviour of thin-walled members made of fibre-reinforced polymer composite laminates. This method allows the application of local shell elements in critical regions of an existing beam-type model. Therefore, it obviates the need for using computationally expensive shell elements in the whole domain of the structure, which is otherwise necessary to capture the effect of the localized behaviour. Consequently, highly accurate analysis results can be achieved with this method by using significantly smaller finite element model, compared to the existing methods. The proposed method can be used for composite polymer laminates with arbitrary fibre orientation directions in different layers of the material, and under various loading conditions. Comparison with full shell-type finite element analysis results are made in order to illustrate the efficiency and accuracy of the proposed technique.

• Korean Journal of Mineralogy and Petrology
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• v.33 no.3
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• pp.259-272
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• 2020

The seismic properties in the crust are affected by the lattice preferred orientation(LPO) of major minerals in the crust. Therefore, in order to understand the internal structure of the crust using seismic data, information on the LPO of the major constituent minerals and the seismic properties of major rocks in a specific region are needed. However, there is little research on the LPOs of minerals in the crust in Korea. In this study, we collected amphibolites from two outcrops in Wigokri, Gapyeong, located in the nothern portion of Gyeonggi Massif, and we measured the LPOs of major minerals of amphibolite, especially amphibole and plagioclase through EBSD analysis, and calculated seismic properties of amphibolite. Two types of LPOs of amphibole, which are defined as type I and type IV, were observed in the two outcrops of Gapyeong amphibolites, respectively. In the case of amphibolites with the type I LPO of amphibole, large seismic anisotropy of both P- and S-wave was observed, while in the amphibolites with the type IV LPO of amphibole, small seismic anisotropy was observed. This is consistent with previous experimental results. The polarization direction of the fast S-wave was aligned subparallel to the lineation regardless of the LPO types of amphibole. The seismic anisotropy observed in Gapyeong is expected to be helpful to interpret the structure and seismic data within the crust in Gyeonggi Massif.

• Journal of Animal Environmental Science
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• v.10 no.1
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• pp.37-46
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• 2004

In order to investigate the effect of floor condition on the fattening performance of cattle, sixteen finishing Hanwoo steers of weighting 570kg were fed for 16 weeks to slaughter on two types of sawdust bedding pen oriented to the south(SP) and the north(NP) then obtained following results. The floor condition of SP roofed by transparent material was dry and flat during overall experimental period, whereas, that of NP roofed by solid slate was muddy and rough even in summer and fall, and then frozen in winter period resulted in interfering with the locomotion and resting behavior of steers. Average daily dry matter intake of steers was not different between tow treatments, however, the average daily gain of steers in NP and SP was 0.64kg and 0.75kg, respectively, meaning that gained 14.3% less for the NP group(p<0.05), accordingly, feed requirement(feed/gain) and TDN/gain increased by 15.9% and 15.5%, respectively. No significant differences were found in slaughter weight, carcass weight, dressing percentage, meat yield index and meat quality traits between two treatments. In conclusion, this study revealed that poor floor condition of feeding pen could decrease weight gain and feed efficiency of cattle by increasing energy consumption for locomotion and conductive energy loss while resting on the floor surface. These results indicates that housing orientation of cattle shed and the selection of roof material are important factors in beef cattle production.

• The Journal of Engineering Geology
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• v.26 no.2
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• pp.177-185
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• 2016

This work investigates whether stress changes induced by an earthquake can be estimated using the deformation measured by high-resolution borehole strainmeters. We estimate the changes in the orientation and magnitude of the principal compression stresses using borehole strainmeter data recorded before and after the M7.2 El Mayor-Cucapah earthquake on April 4, 2010. Clear differences in the stress orientations and magnitudes are apparent before and after the event. The change in stress orientation appears related to subtle increases of stress in the tectonic maximum principal orientation, which is in agreement with the earthquake focal mechanism solution. The sudden stress drop at the onset of the earthquake was 10⁻³-10⁻² MPa in the principal orientations. The Coulomb stress transfer model, which can estimate stress transfer, predicts a shear stress increase of (0.1-0.6) × 10⁻² MPa at the strainmeter site, which is in line with the measured data (0.3-0.8) × 10⁻² MPa. Overall, our results suggest that borehole strainmeter data reflect the subtle stress changes associated with earthquake occurrence, and that such data can be utilized for earthquake-related research.

• Journal of the Korea Fashion and Costume Design Association
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• v.19 no.1
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• pp.1-14
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• 2017

The purpose of this study is to classify the environmental awareness attitudes of university students and analyze their differences in social support pursuit, and apparel consumption behavior. Questionnaires were administered to 236 college students living in Daegu City and Kyoungbuk province. Frequency, factor analysis, reliability analysis, cluster analysis, ANOVA, Duncan-test, and t-test were used for data analysis. The findings were as follows. The environmental awareness attitudes had factors as recognizing the importance of environmental issues, purchase of eco-friendly products, public opinion legislation awareness, interests on eco-friendly product, and eco-friendly practice. Social support pursuit were found as marginal people support pursuit, emotional support pursuit, informational support pursuit, and problem-solving support pursuit. Apparel consumption behavior were found as planned purchase, social participation attitude, clothes recycling, life practice, low-price orientation, emphasis on designs, clothing-life practice, and consciousness over others. The environmental awareness attitudes of university students were classified into four groups of Consumers of Environment-Awareness, Consumers of Environment-interests, Consumers of Environment-practice, and Consumers of Low Environment-awareness. The groups showed significant difference in social support pursuit, and apparel consumption behavior. Gender of university students showed significant differences the environmental awareness attitudes, social support pursuit, and apparel consumption behavior. It is meaningful to find out the significant relationship in a social context between environment recognition and social support pursuit related by friends. This study also offered a basic information related to social support pursuit by the types of university students' environmental awareness attitude and consumption on clothing, which is necessary for environmental education and green consuming behavior.

• Annals of Occupational and Environmental Medicine
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• v.35
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• pp.25.1-25.12
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• 2023

Background: In Korea, little research has focused on the relationship between discrimination in the workplace and sleep health. Thus, this study aims to investigate the association between such discriminatory experiences and insomnia, a common sleep disorder, using Korean employees' data. Methods: This study used data from the 6th Korea Working Conditions Survey. Discrimination experiences due to age, ethnic background, nationality, race, sex, religion, disability, sexual orientation, educational level, hometown, and employment status were investigated. The Minimal Insomnia Symptom Scale estimated insomnia symptoms. The association between discrimination experience and insomnia symptoms were analyzed using survey-weighted logistic regression analysis. Results: Based on experiences of discrimination over the past 12 months, insomnia symptoms were associated with discrimination experience due to religion (odds ratio [OR]: 3.70; 95% confidential interval [CI]: 1.58-8.69), sex (OR: 2.51; 95% CI: 1.87-3.37), age (OR: 2.30; 95% CI: 1.88-2.81), hometown (OR: 2.07; 95% CI: 1.44-2.97), employment status (OR: 1.69; 95% CI: 1.37-2.10), and educational level (OR: 1.67; 95% CI: 1.31-2.14). Furthermore, the prevalence of insomnia symptoms increased with the number of discrimination experiences. Conclusions: In this study, discrimination experiences due to religion, sex, age, hometown, employment status, and educational level were significantly associated with insomnia symptoms. Furthermore, as the number of discrimination experiences increased, so did the prevalence of insomnia. Preventing workplace discrimination may improve workers' sleep health.

• Steel and Composite Structures
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• v.20 no.4
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• pp.813-832
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• 2016

This research deals with the behavior of Composite Box Girder Bridges (CBGBs) subjected to environmental effects such as solar radiation, atmospheric temperature, and wind speed. It is based on temperature and thermal stress results, which were recorded hourly from a full-scale experimental CBGB segment and Finite Element (FE) thermal analysis. The Hemi-cube method was adopted to achieve the accuracy in temperature distributions and variations in a composition system during the daily environmental variations. Analytical findings were compared with the experimental measurements, and a good agreement was found. On the other hand, parametric investigations are carried out to investigate the effect of the cross-section geometry and orientation of the longitudinal axis of CBGB on the thermal response and stress distributions. Based upon individual parametric investigations, some remarks related to the thermal loading parameters were submitted. Additionally, some observations about the CBGB configurations were identified, which must be taken into account in the design process. Finally, this research indicates that the design temperature distribution with a uniform differential between the concrete slab and the steel girder is inappropriate for describing the thermal impacts in design objective.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.6A
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• pp.481-487
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• 2005

In order to increase the autonomous navigation capability of a mobile robot, it is very crucial to develop a method for recognizing a priori known environmental characteristics. This paper proposes an ultrasonic sensor based real-time method for recognizing a priori known indoor environmental characteristics like a wall and corner. The ultrasonic sensor consists of an ultrasonic transmitter and two ultrasonic receivers placed symmetrically about the transmitter. Unlike previous methods the information obtained from the sensor is processed in real-time by extended Kalman filter to be able to correct the position and orientation of robot with respect to known environmental characteristics.

• Hwankyungkyoyuk
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• v.19 no.1 s.29
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• pp.64-79
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• 2006

This study was designed to make valuable suggestions for the development of environmental education(EE) teaching materials through teachers' and students' opinions. In the summer of 2005, an opinionnaire was sent to 1,749 secondary school EE teachers and 270 teachers of them answered. One hundred and six middle school students and 196 high school students in Kyunggi area were also participated in this survey. The opinionnaire in this study was based on the six standards, fairness and accuracy, depth, emphasis on skill building, action orientation, instructional soundness, and usability, developed by NAAEE(1998). Most teachers were totally dependent on textbooks in their teaching EE. They evaluated current EE textbooks most positively in the perspective of 'fairness and accuracy', whereas they evaluated them most negatively in the perspective of 'usability'. The problems of EE textbooks were differently recognized by teachers and students. The lack of contents stimulating students' interest was considered as the most serious problem of EE textbooks by students. Simultaneously, it was considered as the least serious problem of EE textbooks by teachers. Both EE teachers and students expect the future EE textbooks would consist of proper contents to reflect EE characteristics.

• Wind and Structures
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• v.33 no.6
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• pp.437-446
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• 2021

As wind turbine rotors increase, the overall loads and dynamic response become an important issue. This problem is augmented by the exposure of wind turbines to severe atmospheric events with unconventional flows such as tornadoes, which need specific designs not included in standards and codes at present. An experimental study was conducted to analyze the loads induced by a tornado-like vortex (TLV) on horizontal-axis wind turbines (HAWT). A large-scale tornado simulation developed in The Wind Engineering, Energy and Environment (WindEEE) Dome at Western University in Canada, the so-called Mode B Tornado, was employed as the TLV flow acting on a rigid wind turbine model under two rotor operational conditions (idling and parked) for five radial distances. It was observed that the overall forces and moments depend on the location and orientation of the wind turbine system with respect to the tornado vortex centre, as TLV are three-dimensional flows with velocity gradients in the radial, vertical, and tangential direction. The mean bending moment at the tower base was the most important in terms of magnitude and variation in relation to the position of the HAWT with respect to the core radius of the tornado, and it was highly dependent on the rotor Tip Speed Ratio (TSR).