• Journal of Korea Water Resources Association
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• v.51 no.12
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• pp.1171-1180
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• 2018

Korea's water transmission system is operated by the nonpressure flow method that flows from highlands to lowlands due to the nature of Korea with many mountainous areas. In order to store water in the highlands, the water pumps are installed and operated. However, In this process, a lot of electrical energy is consumed. therefore, it is necessary to minimize the energy consumption by optimizing the size and operation schedule of the water pumps. The optimal capacity and operation method of the water pump are affected by the size of the tank (distributing reservoir). Therefore, in order to economically design and operate the water transmission system, it is reasonable to consider both the construction cost of the water pump and the tank and the long-term operation cost of the water pump at the step of determining the scale of the initial facilities. In this study, the optimum design model was developed that can optimize both the optimal size of the water pump and the tank and the operation scheduling of the water pump by using the genetic algorithm (GA). The developed model was verified by applying it to the water transmission systems operated in Korea. It is expected that this study will help to estimate the optimal size of the water pump and the tank in the initial design of the water transmission system.

• Journal of Korean Society on Water Environment
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• v.35 no.4
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• pp.316-331
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• 2019

Carbon dioxide($CO_2$) emission from rivers to the atmosphere is a key component in the global carbon cycle. Most of the rivers are supersaturated with $CO_2$. At a global scale, the amount of $CO_2$ emission from rivers is reported to be five-fold greater than that from lakes and reservoirs, but relevant data are rare in Korea. The objectives of this study is to estimate the $CO_2$ net atmospheric flux(NAF) from the upstream of Gangjeong-Goryeong Weir(GGW), Dalseong Weir(DSW), Hapcheon-Changnyeong Weir(HCW), and Changnyeong-Haman Weir(CHW) located in Nakdong River South Korea) using field and laboratory experiments and to apply data mining techniques to develop parsimonious prediction models that can be used to estimate $CO_2$ NAF with physical and water quality variables that can be collected easily. As a result, the study sites were all heterotrophic systems that often released $CO_2$ to the atmosphere, except when the algal photosynthesis was active.The median $CO_2$ NAF was minimum $391.5mg-CO_2/m^2$ day at GGW and maximum $1472.7mg-CO_2/m^2$ day at DSW. The $CO_2$ NAF showed a negative correlation with pH and Chl-a since the overgrowth of the algae consumed $CO_2$ in the water and increased the pH. As the parsimonious multiple regression model and random forest model developed, this study showed an excellent performance with the $Adj.R^2$ value higher than 0.77 in all weirs. Thus, these methods can be used to estimate $CO_2$ NAF in the river even if there is no $pCO_2$ measurement data.

• Korean Journal of Construction Engineering and Management
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• v.20 no.2
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• pp.28-36
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• 2019

The APR1400 (Advanced Power Reactor 1400MW) nuclear power plant is a large-scale national infrastructure facility with a total project cost of 8.6 trillion won and a project period of 10 years or more. The total project area is about 2.17 million square meters and consists of more than 20 buildings and structures. And the total number of drawings required for construction is about 65,000. In order to design such a large facility, it is important to establish a design standard that reflects the design intent and can increase conformity between documents (drawings). To this end, a design bases document (DBD) reflecting the design bases that extracted in regulatory requirements (e.g. 10CFR50, Korean Law, etc.) is created. However, although the design bases are important concepts that are a big framework for the whole design of the nuclear power plant, they are managed in 2-dimensional by the experts in each field fragmentarily. Therefore, in order to improve the usability of building information, we developed BIM(Building Information Model) based 3-dimensional design bases management system. For this purpose, the concept of design bases information layer (DBIL) was introduced. Through the simulation of developed system, design bases attribute and element data extraction for each DBIL was confirmed, and walls, floors, doors, and penetrations with DBIL were successfully extracted.

• Journal of the Korean Geotechnical Society
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• v.34 no.11
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• pp.21-31
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• 2018

Bucket foundations are widely used in offshore areas due to their various benefits such as easy and fast installations. A bucket is installed using self-weight and the hydraulic pressure difference across the lid generated by pumping out water from inside the bucket. When buckets are installed in high permeable soil such as sands, upward seepage flow occurs around the bucket tip and interior, leading to a decrease in the effective stress in the soil inside the buckets. This process reduces the penetration resistance of buckets. However, the soil inside and outside the bucket can be disturbed due to the upward seepage flow and this can change the soil properties around the bucket. Moreover, upward seepage flow can create significant soil plug heave, thereby hindering the penetration of the bucket to the target depth. Despite of these problems, soil disturbance and soil plug heave created by suction installation are not well understood. This study aims to investigate the behavior of soil during suction installation. To comprehend the phenomena of soil plug heave during installation, a series of small-scale model tests were conducted with different testing conditions. From a series of tests, the effects of tip thickness of bucket, penetration rate, and self-weight were identified. Finally, soil properties inside the bucket after installation were approximated from the measured soil plug heave.

• Journal of the Korean Regional Science Association
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• v.35 no.2
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• pp.33-47
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• 2019

The purpose of this study is to examine the effect of urban decline on Subjective Well-being(SWB). According to the scale of the city, the municipal districts of Korea are classified into metropolitan cities, middle cities, and small cities. The SWB in the growth area, the maintenance area, and the declining area according to the degree of relative decline of each city group was examined. In addition, in order to consider the complex nature of urban decline, SWB was divided into overall life satisfaction, household income satisfaction, and housing environment satisfaction. Panel models were also used to identify the dynamic relationship between the progress of urban decay and the change in SWB. The empirical analysis of this study examined the effect of decline on the SWB for the local residents. As a result, it was confirmed that the effect of urban decline on the SWB of the residents varies according to the size of the city where the individual resides, according th the SWB by the division. In the case of metropolitan inhabitants, the decline of the housing environment of the residents due to deterioration of the physical environment was confirmed as a result of the decline of the city, but the overall life satisfaction was increased due to the decrease of the social costs such as congestion in an overcrowded area. On the contrary, in the case of the residents of the small cities, it is confirmed that the decline of the city reduces the overall life satisfaction, household income satisfaction, and housing environment satisfaction.

• The Journal of Society for e-Business Studies
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• v.24 no.3
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• pp.111-128
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• 2019

In the current procurement system in Korean military, the army, navy and air force have their own distributors, military branches and warehouses. However, especially, it has been hard to have the economy of scale because most of suppliers have shipped their order from the suppliers to each of Korean military directly. Koran military considers the transportation cost as one of the management cost factors among various kinds of cost. Furthermore they have contracted with the suppliers in annual and collectively on the transportation. Hence they have been in trouble with getting efficiency of Defense budget execution because it is hard to make a decision of Defense budget with real transportation cost. Moreover Korean army, navy and air force have their own supply chain separately, so they can not cooperate flexible and quickly when they need. Therefore, in this research, we provide a benchmarking of DTCI (Defense Transportation Coordination Initiative) which has been proved that it has improved the procurement system in US implementing the integrated transportation system with 3PL and military. In addition we propose advanced integrated shipping model using Hub & Spoke system for Korean military. In order to prove its effect, we simulate our model based on the real data of the suppliers' delivery to compare with the current system when it comes to how much we can save the cost. Our research can provide evidence that the integrated procurement system in Korean military will improve Korean military procurement system.

• Asian-Australasian Journal of Animal Sciences
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• v.32 no.4
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• pp.585-591
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• 2019

Objective: This study investigated carcass characteristics and meat quality of purebred Pakchong 5, crossbred pigs sired by Pakchong 5, and crossbred pigs sired by Duroc. Methods: Forty-eight pigs (average body weight of 22.25 kg) were composed of three groups as purebred Pakchong 5 (PP), Large $White{\times}Landrace$ pigs sired by Pakchong 5 (LWLRP), and Large $White{\times}Landrace$ pigs sired by Duroc (LWLRD). Each group consisted of eight gilts and eight barrows. At 109-day-raising period, pigs were slaughtered, and carcass characteristics were evaluated. Longissimus thoracis (LT) muscles from left side of carcasses were evaluated for meat quality and chemical composition. Data were analyzed using general linear model procedure, where group, sex, and their interaction were included in the model. Results: The PP had greater carcass, total lean, and ham percentages than crossbred pigs (p<0.05). LWLRP had thicker backfat and more carcass fat percentage than LWLRD (p<0.05). There were no differences (p>0.05) on cutting percentages from tender loin, loin, boston butt, and picnic shoulder among groups. The PP and LWLRP had larger loin eye area (LEA) than LWLRD (p<0.05). Gilts had more loin percentage and lower $L^*$ value than barrows (p<0.05). No meat color parameters ($L^*$, $a^*$, and $b^*$) were affected by groups (p>0.05). PP and LWLRP had larger muscle fiber diameters than LWLRD (p<0.05). However, water holding capacity, Warner-Bratzler shear force values, and chemical composition of LT were not affected by group or sex (p>0.05). Conclusion: Pakchong 5 purebred has good carcass and lean percentages. Compared to Duroc crossbred pigs, Pakchong 5 crossbreds have similar carcass and lean percentages, larger LEA, and slightly more carcass fat, with comparable meat quality and chemical composition. Pakchong 5 boars are more affordable for very small- to medium-scale pig producers.

• Journal of Korea Water Resources Association
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• v.52 no.5
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• pp.313-323
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• 2019

Deep Tunnel system is a large-scale urban flood control facility installed underground in order to reinforce the lack of drainage systems in developed cities. In a structure like a deep tunnel system, the undular bore generated in the downstream causes a problem in the hydraulic stability of the tunnel. In this study, to investigate the influence of the undular bore on the hydraulic stability at the "Shinwol rainwater storage and drainage system", under construction for the first time in the country, a hydraulic model experiment was conducted on various flooding inflow scenarios. As a result of the hydraulic model experiment carried out in this study, the undular bore generated downstream is trapped in the pipe while moving to upstream, pushes the compressed air. It is judged that overflow occurred by choking the vertical drop shaft in the process when this compressed air is being exhaust through the upstream vertical drop shaft and blocking flood inflow. In addition, the analysis of velocity of undular bore shows that the undular bore transfers energy, and at this time, the pressure rose in the pipe and the velocity increment occurred of the undular bore. Further studies are needed to predict the size and velocity of undular bore, which plays an important role in the hydraulic stability of the tunnel in the deep tunnel system.

• The Journal of the Korea Contents Association
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• v.19 no.5
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• pp.217-232
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• 2019

As the role of entrepreneurship has become more important for continuous business growth in a rapidly changing economic environment, numerous studies dealing with entrepreneurship are taking place. However, recent studies has concentrated mainly on business-oriented entrepreneurship which emphasizes corporate efficiency only. While in the era of fourth industrial revolution human resources are more important than corporate efficiency, the existing literature is largely focused on traditional entrepreneurship. Research on humane entrepreneurship has not been rigorous, and there are few studies involving small and medium-size enterprises (SMEs) in particular. The purpose of this study is to fill in this void by investigating the effect of humane entrepreneurship on core competencies of SMEs and the effect of these core competencies on corporate performance. To examine SMEs core competencies and their performance from the perspective of humane entrepreneurship, this study set up traditional entrepreneurship and humane entrepreneurship as variables, and develop research model based on these variables. This study tests 5 different hypothesis using this model. A survey was conducted among CEOs and executives at SMEs in Seoul and Gyeonggido, South Korea from, June 26 to August 1, 2018. A total of 310 questionnaires were analyzed. The results show that both traditional and human entrepreneurship have a positive effect on the core competencies of SMEs, which are core competency factors, and that core competencies positively affect both non-financial performance and financial performance. Moreover, non-financial performance is found to have positive effect on financial performance. Given these findings, this study suggests that humane entrepreneurship is critical to SMEs and their performance, no less than traditional entrepreneurship. This study provides profound implications of necessity of raising humane entrepreneurship in environment of companies.

• The Korean Journal of Psychodrama
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• v.21 no.2
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• pp.13-26
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• 2018

The purpose of this study was to determine Enneagram personality type and the degree of clinical practice stress by personality type among nursing students, as well as to set a direction for student counseling and develop a management program. For this purpose, the Enneagram personality type inventory, developed by the Korea Enneagram Spirituality Institute, and a clinical practice stress scale were applied to juniors and seniors majoring in nursing in a district who were in clinical practice. The results were analyzed using an SPSS 25.0 program. Type 2 among the nine Enneagram personality types accounted for 47.66% while in the strength- centered area, the emotional area accounted for 64.84%. As for the degree of clinical practice stress by Enneagram personality type, Type 6 was most vulnerable to the training environment, Type 4 to an undesirable role model and conflicts with patients, and Type 5 to the burden of training tasks and conflicts in interpersonal relationships among the sub-areas of stress. As for the degree of clinical practice stress by the strength-centered area of Enneagram, the thinking type was most vulnerable to the training environment, an undesirable role model, the burden of training tasks, and interpersonal relationships, whereas the emotional type to conflicts with patients. To put these results together, nursing students varied in Enneagram personality type and differed in clinical practice stress by the strength-centered area, as well as by personality type. It is therefore necessary to provide nursing students with counseling and guidance through an analysis of their personality type.