• Journal of the Korea institute for structural maintenance and inspection
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• v.24 no.5
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• pp.45-52
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• 2020

An open-spandrel arch bridges, which consists of slab deck, arch rib, and vertical members, shows a various level of moment and axial forces according to the supporting boundary condition of arch rib and vehicle speeds. Also, the definition of impact factor accepts any kind of response parameters, not only displacement response at slab deck. The present study considers concrete open-spandrel arch bridges constrained with fixed conditions at the ends of arch rib and investigates the impact factor variation due to moving load speeds, response parameters, measuring locations, and vertical member spacing ratio of the bridges. The results of Reference model show that the impact factor is biggest when the reactive moment resulted at the vehicle-inducing opposite end of the arch rib is applied. The peak impact factor is a similar level obtained for the middle of the span adjacent to the slab deck center, but it is 19% higher than the peak impact factor calculated using the axial force developed at the same location. Reducing the spacing ratio of the vertical members as half as the reference model whose ratio is 1/9.375 produces a similar level of the moment-based peak impact factor compared to the reference model. However, when the spacing ratio is doubled, the peak impact factor is 4.4 times greater than the reference model.

• Journal of Korea Entertainment Industry Association
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• v.14 no.8
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• pp.1-9
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• 2020

Self-efficacy and entrepreneurial self-efficacy on the positive effects of entrepreneurial intention are well developed in past research but marketing self-efficacy, linked to the competencies of marketing field and is closely related to self-efficacy and entrepreneurial self-efficacy has not received enough attention on the prediction of start-up intention despite marketing and entrepreneurship are crucial when creating a start-up. Moreover, there have been several empirical studies but, most of the previous studies have focused on university students majoring in business and economics. Therefore, there is still little understanding of the effect of marketing self-efficacy on start-up intention. The purpose of this study then was to investigate the effect of marketing self-efficacy on start-up intention for college students majoring in entertainment-related studies. Questionnaires were employed to collect data from three universities in Korea. A total of 120 completed questionnaires were returned. Logistic regression analysis was used to test the hypothesis. The results indicate that marketing self-efficacy was positively and significantly related to start-up intention. The results of this study empirically confirmed that university students majoring in entertainment-related studies with high marketing self-efficacy are more likely to desire to create a start-up. These results suggest theoretical and practical implications.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.4A
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• pp.537-548
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• 2008

Recently, the prestressed unbonded concrete structures are increasingly being built. The mechanical behavior of prestressed concrete beams with unbonded tendon is different from that of normal bonded PSC beams in that the increment of tendon stress was derived by whole member behavior. The purpose of the present paper is therefore to evaluate the flexural behavior and to propose the equation of ultimate tendon stress by performing static flexural test according to span/depth, concrete compression strength, reinforcement ratio and the effect of existing bonded tendon. From experimental results, for cracking, yielding and ultimate load, the effect of reinforcement ratio was more effective than concrete compression strength, and the beams having high strength concrete had a good performance than having low concrete, but there was no difference between high strength and low strength. And as L/dp was larger, test beams had a long region of ductility. This means that unbonded tendon has a large contribution after reinforcement yielding. Especially, the equation of ACI-318 was not match with test results and had no correlations. After analysis of test results, the equation of ultimate unbonded tendon stress without slip was proposed, and the proposed equation was well matched with test results. So the proposed equation in this paper will be a effective basis for the evaluation of unbonded tendons without slip, analysis and design.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.1B
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• pp.79-88
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• 2006

In this study, a methodology is developed for flood runoff analysis considering the interaction between interior floodplain and channel. Riparian lowland is modeled as storage areas by HEC-RAS and is connected with main channel through gravity drainage structure and pumping stations. As a result, we were able to compute the difference between runoff into the interior floodplain and delayed runoff to main channel from interior floodplain. This allowed us to compute the storage change in the interior floodplain and corresponding inundation areas. Furthermore, the levee is modeled as a lateral structure and the flood from the main channel to interior floodplain is modeled by installing a weir on top of it. In addition, levee breach is also modeled so that flooding from main channel to interior floodplain can be considered. Computed flooding depth in the storage areas are compared with elevation to identify the inundated areas and flood maps can then be produced for a desired time or for the extent of flooding given a flooding depth. Output from this modeling effort can provide many useful information for flood planning such as flow depth in main channel, flooding depth and area in interior floodplain. The method was applied to Sapgyo river basin and the comparison with observed flood events showed that it can reproduce the observation fairly well, hence proving the utility of the method.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.3D
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• pp.385-391
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• 2006

It is very important to make a decision for locating public facility site in a objectively way people in general agree with. This is because public facility affects not only daily life of people in there but also a regional development. This paper sets up a site selection model which utilize an accessibility theory and GIS spatial analysis techniques. This model has been applied to all the twelve alternatives of Chungnam Provincial Office (CPO) sites which are well known to the public. On the criterion of average access time from all the other areas in Chungnam Province, CH alternative is found to be the best one followed by CH/AS, AS alternatives. On the basis of total people-travel time CH/AS alternative turns out to be the best one followed by CH, AS alternatives. In conclusion top three best locations for CPO are CH and AS area where transportation facility are in good condition and population density is highest in Chungnam Province. This fact implies that a transportation accessibility and population density are the primary key in determining the location of public facility.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.4A
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• pp.315-327
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• 2009

In this study, the static test of CFT truss girders for different f/L ratios was conducted to determine how the ultimate strength of the CFT truss girder was affected by different f/L ratios. A total of two CFT truss girders were constructed and tested under bending condition. The length of all specimens is 20,000 mm. The CFT truss girder is a tubular truss composed of chord members made of concrete-filled circular tubes. The main parameter analyzed in the experimental study was the f/L ratio. This factor was experimentally investigated to assess their influence on ultimate strength and stiffness. The test results show that CFT truss girder has good elastic-plastic property and ductility. The presence of the f/L ratios in CFT truss girders alters its ultimate strength because of the global stiffness of the CFT truss girders. The ultimate strength of CFT truss girders increases as the f/L ratio increases. If the f/L ratio of the CFT truss girders increases twofold, the ultimate strengths increase by 80%. The CFT truss girders showed that they retained large deformation capacity, even after reaching the ultimate strength. Results of this investigation demonstrated the potential for efficiently using a CFT truss as a bridge girder.

• Journal of Wetlands Research
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• v.26 no.3
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• pp.285-297
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• 2024

This study, conducted in Geolpo-dong and Gamjeong-dong near Gimpo-Hangang New Town, examines an area adjacent to the Han River estuary, a major wintering ground for migratory birds. Over 59 surveys from October 2015 to March 2022 in four representative rice fields (sites A-D) recorded 44,942 individuals from 32 genera and 72 species. Site D, a large area near the Han River, exhibited high species diversity. Despite lower diversity in areas under development (sites A, B, C), ongoing species influx and utilization persist. The study focuses on Anser fabalis, a species predominantly utilizing rice fields, and identified their distribution characteristics. The analysis revealed 162 instances of population influx, with over a 30-fold increase observed across 39 surveys conducted over a 30-month period (October to March, '15~'22). The area, a key wintering site for migratory birds of Janghang Wetland, about 5 km from feeding sites, is heavily utilized by migratory geese, indicating the region's high value considering migration distance and anticipated continuous bird influx despite urban expansion. Therefore, future developments should preserve ecological corridors and connected stepping stone habitats to not only preserve existing habitats but to secure alternative feeding sites, ensuring smooth movements and mitigating habitat loss.

• Korean Journal of Soil Science and Fertilizer
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• v.19 no.4
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• pp.315-320
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• 1986

The investigation was conducted to find out amounts and ratios of N, P and K fertilizers applied on rice in 410 farmers' fields. The application ranges of N, P and K fertilizers, respectively, were 15.4-16.3, 7.6-8.0 and 8.2-8.5kg/10a for high yielding varieties, and 13.1-13.8, 7.0-7.1 and 6.4-7.7kg/10a for ordinary varieties. N fertilizer was applied in the ratio of 56% at basal dressing, 34% at tillering, 9% at panicle formation and 1% at heading stage. The amounts of soil amendment application were 179-192kg/10a for silicate, 1,031-1,360kg/10a for compost, 420-540kg/10a for rice straw, and 17.8-25.2 ton/10a for red earth.

• Journal of The Korean Society of Grassland and Forage Science
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• v.36 no.4
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• pp.387-392
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• 2016

This study was conducted to ameliorate the productive performance of Hanwoo cow using hill pasture grazing system. Twenty seven animals aged 9 were designed to divide with 3 groups which were Control (restricted concentrate and hay for 5 months), T1 (restricted concentrate and pasture grazing ad libitum for 5 months) and T2 (restricted concentrate, 30 g/head of mineral nutrients and pasture grazing ad libitum for 5 months). Average daily gains increased higher in the order of T2, Control and T1. The conception rate of Control, T1 and T2 after artificial insemination during post-grazing period were 88.9%, 100%, 100%, respectively. In conclusion, the results indicated that hill pasture grazing system might enhance not only the productive performance of Hanwoo cow but also profit for conventional feeding system.

• Tuberculosis and Respiratory Diseases
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• v.43 no.4
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• pp.536-546
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• 1996

Background : The survival benefit of combination chemotherapy comparing supportive care to patients with advanced non-small cell lung cancel, especially stage IV non-small cell lung cancer patients with metastatic disease, is controversial. The main goal of this study was to evaluate the difference in survival between patients treated with chemotherapy and those who were not and to identify prognostic factors in the patients with stage IV non-small cell lung cancer. Methods : From January 1989 to December 1994, total 67 patients including 20 patients treated with combination chemotherapy and 47 patients treated with only supportive care in stage IV non-small cell lung cancer patients with metastatic disease were enrolled in this study. Combination chemotherapy consisted of etoposide $120mg/m^2$ iv for 3 days and cis-platin iv day 1 every 4 weeks. The treatment groups were retrospectively analyzed by age, sex, histologic cell type, weight loss, serum LDH level, ECOG performance status and major organ metastasis. Results : The significant prognostic factors influencing survival on this study were ECOG performance status and histologic subtype. Overall response rate by combination chemotherapy was 30%(complete response 0%, partial response 30%). Median survival of overall patients was 13.6 weeks and median survival of Chemotherapy group, 20 weeks, was significantly longer than that of supportive care group, 11.7 week(p<0.01). Median survival of responded in patients receiving chemotherapy, 45.5 weeks, was significantly longer than that of non-responder, 17.3 weeks(p<0.05). 1 year-survival rate of chemotherapy group and supportive care group was 15N and 8%, respectively. Nausea or vomiting, alopecia and anemia were seen in nearly most cases after this combination chemotherapy. Toxicities above grade 3 included neutropenia, anemia, thrombocytopenia, infection, fever, nausea, vomiting and alopecia. But this combination chemotherapy was relatively well tolerated except one treatment-related death from sepsis associated with severe granulocytopenia. Conclusion : These results suggest that systemic chemotherapy might be helpful to the stage IV non-small cell lung cancer patients with good performance status and large scale randomized prospective trials should be performed.