• Journal of the Korea institute for structural maintenance and inspection
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• v.18 no.3
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• pp.10-19
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• 2014

Corrugated steel plates are made by fabricating thin steel plates to have trapezoidal or sinusoidal corrugation, and the corrugated plates are able to maintain high out-of-plane rigidity even when they are used instead of thick flat plates. Also, corrugated steel plates have almost no axial rigidity due to the accordion effect. Thus, if they are applied to the webs of plate girders, designing can be easily conducted so that the webs bear only shear stresses. However, unlike flat plates, the shear buckling of corrugated steel plates has very complex characteristics where buckling occurs due to the interaction of local and global buckling, besides local buckling and global buckling. For the investigation of the cause and characteristics of this interactive buckling, studies on sinusoidal corrugated steel plates are fewer than studies on trapezoidal corrugated steel plates. Therefore, in this study, the shear buckling characteristics of sinusoidal corrugated steel plates and the occurrence pattern of interactive buckling were investigated. For the calculation of shear buckling strength, a finite element program was used, and the analysis results were compared with the exact solution. In addition, the characteristics of buckling stress change and the change of buckling mode shape depending on corrugation thickness and shape parameter were analyzed, and by comparing these results with the results of a theoretical equation, the timing of buckling mode change was analyzed.

• Journal of Digital Convergence
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• v.12 no.11
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• pp.395-405
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• 2014

This study tends to grasp the physical activity on its influences and effect s to the mental health of middle school students and we tried to look for a specific plan that will help to improve middle school students' mental health. We analyzed 36,530 students in middle school using a basic data "9th (2013) health behavior of juvenile on the online". The study is analyzed by complex sample data analysis method. The degree of euphoria recognition showed the low feeling of happiness when students exercise directly below two times rather than three times a week in the Physical Education class at school. On the other hand, the possibility of stress perception degree and suicide attempt is lowered. If the number of sports team participating is below one team, euphoria would be lowered and the limit of stress perception is high. However, the participation of one or two teams make the possibility of suicide lessens rather than students taking part in more 4 teams. In order to help middle school students reduce their stress and improve their happiness, they need to participate in sports as a regular team and join intramural games more than three times a week. In this case of the lower grade, it is considered that it is necessary for them to combine the educational program for the emotional support to control their extreme behavior.

• Journal of the Korean Chemical Society
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• v.62 no.5
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• pp.358-363
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• 2018

The purpose of this study is to show the possibility of using Cu catalyst in removal of $NO_x$ from automobile exhaust which is regarded as the primary source of fine dust PM2.5. The energy and the bond lengths of the three possible structures of Cu-NO complex, which is formed by binding NO molecule to Cu, and the changes in IR and Raman spectra are calculated using MPW1PW91 method on the level of 6-311(+)G(d,p) of basis sets with Gaussian 09 program. As a result, the enthalpy of formation of the Cu-NO complexes are obtained as ${\Delta}H=104.89$, 91.98, -127.48 kJ/mol for the linear, bent, and bridging forms of them, respectively. And the bond lengths between N and O in NO complexes, which becomes longer than NO molecule, indicates that O is easily reduced from Cu-NO. In addition, the Cu-NO complexes using Cu catalyst can be easily measured by infrared or Raman spectroscopy because in the IR and Raman spectra of the NO and Cu-NO complexes the positon and the intensity of bands are definitely different in each vibration mode.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.23 no.3
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• pp.303-314
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• 2010

A study for the nonlinear analysis method of prestressed concrete(PSC) girders with external tendons is presented. The PSC girders with external tendons show the complex nonlinear behavior due to the slip of external tendons at deviator and the change of eccentricity between the girders and external tendons. The external tendon between anchorage-deviator or deviator-deviator is modeled as an assemblage of the curved elements. The slip effect of the external tendon at deviator is taken into account using the force equilibrium relationship between the friction force and the driving force at each deviator. The finite element model and analysis method of the external tendon suggested herein are integrated in the nonlinear analysis program of segmentally erected PSC frames developed by the authors. The proposed analysis method is verified through the comparison of the analysis and experimental results obtained from other investigators. From the ultimate analysis results of PSC beams with external tendons having different number of deviators, the yielding and ultimate loads of PSC beams found to be increased as the number of deviators are increased. In addition, the ultimate capacity of the PSC beam increases according to the increase of friction coefficient between deviator and external tendon, whereas found to decease over the certain value of friction due to the effect of the moment transmitted to the member by the friction force exerted from the external tendon.

• Land and Housing Review
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• v.9 no.3
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• pp.29-36
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• 2018

This study aims at suggesting directions to make children's parks considering the actual groups using them by comparative analysis of age distribution in residents within area of use and locations of children's parks with regards to changes in population structure of low birth rate and aging. Cheongju was selected for the study, and the current status of children's parks and population structure were categorized into six stages and the investigation and analysis were conducted by statistics by population group and by using Arc GIS Program. As a result of the analysis, children under 13 were 13.1% of the entire population in Cheongju and share of middle-aged and aged group including middle-aged was 31.3%. Park area per one children under 13 was 5.9㎡ and based on walking use area(250m), average number of parks available by autonomous district was eight. As a result of the analysis of characteristics of distribution of children's parks, they are densely located in old downtowns or the distribution density was relatively high in newly developed areas such as Osong-eup or Ochang-eup. However, outer rural areas have no children's parks or relatively low rate. As a result of the analysis on population structure and co-efficient of park location, in nine autonomous districts, aged group is increasing, leading to decrease use of children's parks. If resident rate aged group is higher in the region where a children's park is located, it is necessary to re-compose the existing one to different one or to change purposes of parks to be planned. Also, in the area with similar rates in both children's group and aged group, composing complex parks for both of them could be considered. This study has limitations by not conducting field studies about the current status of use of children's parks in areas where the population structure has been changing and not suggesting specifically new types of parks according to changes in population structure. It is necessary to conduct the following studies about relationship between children's parks and policies for composing parks responding to changes in population structure in neighboring regions in future.

• The Journal of the Korea Contents Association
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• v.12 no.6
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• pp.317-327
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• 2012

The purpose of present study was to observe the path and influencing effects between socioeconomic class (SEC), health practices and self-rated health(SRH) by the age bracket. The subjects were 4,987 adults over 25 years old who participated in the 2008 Korean National Examination Health and Nutrition Survey and could be classified into SEC in terms of the three characteristics: education, income and occupation. Path analysis was conducted with the effects of health behaviors execution on the differences in SRH, and the complex samples analysis executed by chi-square test, t-test, ANOVA. As the result, lower SRH level paralleled with the lower SEC, and more health behaviors had differed by SEC in the younger and middle aged group. The lower SEC, the lower SRH: non-smoking and weight control for younger women and exercise for aged men had indirect effects as parameters. In conclusion, when planning a health promotion program, to select the correct target populations with consideration of the age bracket, gender and SEC and to establish tailored contents fit for each of the population would be important.

• Korean Journal of Agricultural and Forest Meteorology
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• v.6 no.3
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• pp.170-176
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• 2004

This study was carried out to establish a spatial decision support system for evaluating climatic aspects of a given geographic location in complex terrains with respect to the quality apple production. Monthly climate data from S6 synoptic stations across South Korea were collected for 1971-2000. A digital elevation model (DEM) with a 10-m cell spacing was used to spatially interpolate daily maximum and minimum temperatures based on relevant topoclimatological models applied to Jangsoo county in Korea. For daily minimum temperature, a spatial interpolation scheme accommodating the potential influences of cold air accumulation and the temperature inversion was used. For daily maximum temperature estimation, a spatial interpolation model loaded with the overheating index was used. Freezing risk in January was estimated under the recurrence intervals of 30 years. Frost risk at bud-burst and blossom was also estimated. Fruit quality was evaluated for soluble solids, anthocyanin content, Hunter L and A values, and LID ratio, which were expressed as empirical functions of temperature based on long-term field observations. AU themes were prepared as ArcGlS Grids with a 10-m cell spacing. Analysis showed that 11 percent of the whole land area of Jangsoo county might be suitable for quality 'Fuji' apple production. A computer program (MAPLE) was written to help utilize the results in decision-making for site-selection of new orchards in this region.

• Journal of Distribution Science
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• v.16 no.9
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• pp.65-77
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• 2018

Purpose - A trading area is very closely related to consumer life. A trading area is a cultural and social space that consumes culture and promotes human relationships as well as an economic space where consumers live their daily lives. In this context, a trading area research should be conducted objectively and empirically because it deals with the activities of consumer's life. The purpose of this study is to identify the intrinsic psychological motivation(push motivation) caused when consumers visit a trading area and to demonstrate how the push motivation for a trading area influence on consumer's flow, satisfaction, revisit intention. Research design, data, and methodology - In order to develop research hypotheses for this study, the development procedures for push motivation scale are as follows; (1) generating initial pool of items based on previous studies, (2) expert judgement to evaluate content and face validity, and (3) assessing convergent and discriminant validity using confirmatory factor analysis. In order to achieve these purposes, online surveys were conducted on frequent or familiar visitors to the trading areas around the Gangnam, Kunkuk University and Hongik University Station. Among the 1,343 questionnaires collected, 1,157 cases were analyzed by using SPSS 22.0 and SmartPLS 3.0 statistical package program, except for 186 responses in which responses were judged to be unfaithful. Results - The push motivation was classified into five sub-dimensions of excitement/stimulus, rest/relaxation, exit/refreshing, knowledge/learning and human relationship promotion as multidimensional and complex factors composed of individual and social-related dimensions. The excitement/stimulus and human relationship promotion of push motivation have positive effects on satisfaction. However, all dimensions of the push motivation have positive effects on flow. And flow has a positive effect on satisfaction and revisit intention. Meanwhile, the mediation test using boostrapping shows that flow plays a full mediating role in the relationship between rest/relaxation, exit/refreshing, knowledge/learning and satisfaction, but a partial mediating rol e between excitement/stimulus, human relationship promotion and satisfaction. Finally, satisfaction plays a partial mediating role between flow and revisit intention. Conclusions - This study shows that the push motivation is multidimensional and compositive depending on the situation of a consumer. In addition, it is found that the human relationship promotion(a social-related motivation) has a much more important effect on flow and satisfaction than other push motivations of individual dimensions. It also shows that satisfaction increases when consumers are being flowed at their visit and degree of revisit intention also grows as satisfaction increases. As implications of this study, a marketer should try to understand consumer's visit motivation at first and then develop factors that increase their flow, satisfaction, revisit intention. It also requires a marketer to approach subjects on a trading area more objectively and empirically based on the psychology and behavior of consumers, in order to establish a proper and efficient strategy on development of a trading area.

• Journal of the Korea Concrete Institute
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• v.17 no.6 s.90
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• pp.955-962
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• 2005

Still no accurate theory exists for predicting ultimate shear strength of deep reinforced concrete beams because of the structural and material non-linearity after cracking. Currently, the load capacity assesment is performed for the upper structure of the bridges and containing non-reliability in the applications and results. The purpose in this study is to evaluate analytically the complex shear behaviors and normal strength for the reinforced concrete deep beams and to offer the accuracy load capacity assesment method based on the reliability theories. This paper presents a method for the load capacity assesment of reinforcement concrete deep beams using nonlinear finite element analysis. A computer program named RCAHEST (Reinforced Concrete Analysis in Higher Evaluation System Technology), for the analysis of reinforced concrete structures was used. Material non-linearity is taken Into account by comprising tensile, compressive and shear models of cracked concrete and a model of reinforcing steel. From the results, determine the reliability index for the failure base on the Euro Code. Then, calculate additional reduction coefficient to satisfy the goals from the reliability analysis. The proposed numerical method for the load capacity assesment of reinforced concrete deep beams is verified by comparison with the others methods.

• Journal of the Korea Concrete Institute
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• v.14 no.3
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• pp.382-391
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• 2002

This study is devoted to the problems of thermal and shrinkage stresses in order to avoid cracking at early ages. The early-age damage induced by volume change has great influence on the long-term structural performance of the concrete structures such as its durability and serviceability To solve this complex problem, the computer programs for analysis of thermal and shrinkage stresses were developed. In these procedures, numerous material models are needed and the realistic numerical models have been developed and validated by comparison with relevant experimental results in order to solve practical problems. A framework has been established for formulation of material models and analysis with 3-D finite element method. After the analysis of the temperature, moisture and degree of hydration field in hardening concrete structure, the stress development is determined by incremental structural formulation derived from the principle of virtual work. In this study, the stress development is related to thermal and shrinkage deformation, and resulting stress relaxation due to the effect of early-age creep. From the experimental and numerical results it is found that the early-age creep p)ays important role in evaluating the accurate stress state. The developed analysis program can be efficiently utilized as a useful tool to evaluate the thermal and shrinkage stresses and to find measures for avoiding detrimental cracking of concrete structures at early ages.