• KIPS Transactions on Computer and Communication Systems
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• v.1 no.3
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• pp.143-150
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• 2012

A simulation methodology and corresponding program based on it is to be discussed for analyzing the effects of the networking operation of existing DHC system in connection with CHP system on-site. The practical simulation for arbitrary areas with various building compositions is carried out for the analysis of operational features in both systems, and the various aspects of thermal energy grids with connecting operation are highlighted through the detailed assessment of predicted results. The intrinsic operational features of CHP prime movers, gas engine, gas turbine etc., are effectively implemented by realizing the performance data, i.e. actual operation efficiency in the full and part loads range. For the sake of simplicity, a simple mathematical correlation model is proposed for simulating various aspects of change effectively on the existing DHC system side due to the connecting operation, instead of performing cycle simulations separately. The empirical correlations are developed using the hourly based annual operation data for a branch of the Korean District Heating Corporation (KDHC) and are implicit in relation between main operation parameters such as fuel consumption by use, heat and power production. In the simulation, a variety of system configurations are able to be considered according to any combination of the probable CHP prime-movers, absorption or turbo type cooling chillers of every kind and capacity. From the analysis of the thermal network operation simulations, it is found that the newly proposed methodology of mathematical correlation for modelling of the existing DHC system functions effectively in reflecting the operational variations due to thermal energy grids with connecting operation. The effects of intrinsic features of CHP prime-movers, e.g. the different ratio of heat and power production, various combinations of different types of chillers (i.e. absorption and turbo types) on the overall system operation are discussed in detail with the consideration of operation schemes and corresponding simulation algorithms.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.2
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• pp.115-123
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• 2013

Stoker type incinerator is one of the most popular one used as municipal solid waste (MSW) incineration because, in general, it is quite suitable for large capacity and need no preprocessing facility. Nowadays, however, since the combustible portion of incoming MSW increases together with the decrease of the moisture content due to prohibition of directly burying food waste in landfill, the heating value of waste is remarkably increasing in comparison with the early stage of incinerator installation. Consequently, the increased heating value in incinerator operation causes a number of serious problems such as reduction of waste amount to be burned due to the boiler heat capacity together with the significant NO generation in high temperature environment. Therefore, in this study, a series of numerical simulation have been made as parameters of waste amount and the fraction of moisture in air stream in order to investigate optimal operating condition for the resolution of the problems associated with the high heating value of waste mentioned above. In specific, a detailed turbulent reaction flow field calculation with NO model was made for the full scale incinerator of D city. To this end, the injection method of moisturized air as oxidizer was intensively reviewed by the addition of moisture water amount from 10% and 20%. The calculation result, in general, showed that the reduction of maximum flame temperature appears consistently due to the combined effects of the increased specific heat of combustion air and vaporization heat by the addition of water moisture. As a consequence, the generation of NOx concentration was substantially reduced. Further, for the case of 20% moisture amount stream, the afterburner region is quite appropriate in temperature range for the operation of SNCR. This suggests the SNCR facility can be considered for reoperation. which is not in service at all due to the increased heating value of MSW.

• Fire Science and Engineering
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• v.31 no.5
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• pp.53-62
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• 2017

Electric power which is the energy source of economy and industries requires long distance transportation due to regional difference between its production and consumption, and it is supplied through the multi-loop transmission and distribution system. Prior to its actual use, electric power flows through several transformations by voltage transformers in substations depending on the characteristics of each usage, and a transformer has the structure consisting of the main body, winding wire, insulating oil and bushings. A transformer fire that breaks out in substations entails the primary damage that interrupts the power supply to houses and commercial facilities and causes various safety accidents as well as the secondary economic losses. It is considered that causes of such fire include the leak of insulating oil resulting from the destruction of bottom part of bushings, and the chain reaction of fire due to insulating oil that reaches its ignition point within 1 second. The smoke detector and automatic fire extinguishing system are established in order to minimize fire damage, but a difficulty in securing golden time for extinguishing fire due to delay in the operation of detector and release of gas from the extinguishing system has become a problem. Accordingly, this study was carried out according to needs of active mechanism to prevent the spread of fire and block the leak of insulating oil, in accordance with the importance of securing golden time in extinguishing a fire in its early stage. A bushings fireproof structure was developed by applying the high temperature shape retention materials, which are expanded by flame, and mechanical flame cutoff devices. The bushings fireproof structure was installed on the transformer model produced by applying the actual standards of bushings and flange, and the full scale fire test was carried out. It was confirmed that the bushings fireproof structure operated at accurate position and height within 3 seconds from the flame initiation. It is considered that it could block the spread of flame effectively in the event of actual transformer fire.

• Current Research on Agriculture and Life Sciences
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• v.4
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• pp.119-123
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• 1986

The study was conducted to find out the gene effects on body weights at weaning and at the age of 60 days in mice, with 343 progenies from full-dialell crosses of four lines of BALB/c, CBA, C3H and C57BL. The progenies were reared at the Experimental Animal Farm, College of Agriculture, Kyungpook National University from November, 1984 to February, 1985, and data collected from the progenies were analyzed into general combining ability, maternal effects, specific combining ability and reciprocal effects with Harvey's model. General combining ability effects estimated in line-crosses were -0.6033~0.5298 for weaning weights and -0.5086~1.0012 for body weights at the age of 60 days. General combining ability for BALB/c and C57BL were significantly better than general combining ability for CBA and C3H for both traits (P<0.05). Maternal effects for C3H were significantly larger than the maternal effects of BALB/c for both traits (P<0.05). The estimates of maternal effects were -0.9678~0.4609 for weaning weights and -1.1886~0.0729 for body weights at the age of 60 days. Specific combining ability effects were estimated to be significant (P<0.05), and the estimates were -0.1999~0.3380 for weaning weights and -0.4056~0.3317 for body weights at the age of 60 days. Reciprocal effects were found to be largest in BALB/c${\times}$C57BL and BALB/c${\times}$C3H. The estimates were -0.5049 from BALB/c${\times}$C57BL and 0.4972 from BALB/c${\times}$C3H form weaning weights, and -1.0336 from BALB/c${\times}$C57BL and 1.2793 from BALB/c${\times}$C3H for body weights at the age of 60 days.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.237-237
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• 2015

The district of Marlborough has had more than its share of river management projects over the past 150 years, each one uniquely affecting the geomorphology and flood hazard of the Wairau Plains. A major early project was to block the Opawa distributary channel at Conders Bend. The Opawa distributary channel took a third and more of Wairau River floodwaters and was a major increasing threat to Blenheim. The blocking of the Opawa required the Wairau and Lower Wairau rivers to carry greater flood flows more often. Consequently the Lower Wairau River was breaking out of its stopbanks approximately every seven years. The idea of diverting flood waters at Tuamarina by providing a direct diversion to the sea through the beach ridges was conceptualised back around the 1920s however, limits on resources and machinery meant the mission of excavating this diversion didn't become feasible until the 1960s. In 1964 a 10 m wide pilot channel was cut from the sea to Tuamarina with an initial capacity of $700m^3/s$. It was expected that floods would eventually scour this 'Wairau Diversion' to its design channel width of 150 m. This did take many more years than initially thought but after approximately 50 years with a little mechanical assistance the Wairau Diversion reached an adequate capacity. Using the power of the river to erode the channel out to its design width and depth was a brilliant idea that saved many thousands of dollars in construction costs and it is somewhat ironic that it is that very same concept that is now being used to deal with the aggradation problem that the Wairau Diversion has caused. The introduction of the Wairau Diversion did provide some flood relief to the lower reaches of the river but unfortunately as the Diversion channel was eroding and enlarging the Lower Wairau River was aggrading and reducing in capacity due to its inability to pass its sediment load with reduced flood flows. It is estimated that approximately $2,000,000m^3$ of sediment was deposited on the bed of the Lower Wairau River in the time between the Diversion's introduction in 1964 and 2010, raising the Lower Wairau's bed upwards of 1.5m in some locations. A numerical morphological model (MIKE-11 ST) was used to assess a number of options which led to the decision and resource consent to construct an erodible (fuse plug) bank at the head of the Wairau Diversion to divert more frequent scouring-flows ($+400m^3/s$)down the Lower Wairau River. Full control gates were ruled out on the grounds of expense. The initial construction of the erodible bank followed in late 2009 with the bank's level at the fuse location set to overtop and begin washing out at a combined Wairau flow of $1,400m^3/s$ which avoids berm flooding in the Lower Wairau. In the three years since the erodible bank was first constructed the Wairau River has sustained 14 events with recorded flows at Tuamarina above $1,000m^3/s$ and three of events in excess of $2,500m^3/s$. These freshes and floods have resulted in washout and rebuild of the erodible bank eight times with a combined rebuild expenditure of $80,000. Marlborough District Council's Rivers & Drainage Department maintains a regular monitoring program for the bed of the Lower Wairau River, which consists of recurrently surveying a series of standard cross sections and estimating the mean bed level (MBL) at each section as well as an overall MBL change over time. A survey was carried out just prior to the installation of the erodible bank and another survey was carried out earlier this year. The results from this latest survey show for the first time since construction of the Wairau Diversion the Lower Wairau River is enlarging. It is estimated that the entire bed of the Lower Wairau has eroded down by an overall average of 60 mm since the introduction of the erodible bank which equates to a total volume of $260,000m^3$. At a cost of $$0.30/m^3$ this represents excellent value compared to mechanical dredging which would likely be in excess of $$10/m^3$. This confirms that the idea of using the river to enlarge the channel is again working for the Wairau River system and that in time nature's "excavator" will provide a channel capacity that will continue to meet design requirements.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.14 no.5
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• pp.93-104
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• 2019

The entrepreneurship can be a source of national growth potential as behavioral tendencies of people who seek innovation, take risks of failure, and proactively respond to opportunities. In particular, in the economic situation of Korea where growth has been stagnated, it is necessary to strengthen the entrepreneurship of women which is relatively lower than men's in order to activate the start-up and economic participation of the whole people. In this regard, this study focuses not only on gender differences in entrepreneurship but also on the hidden impact of social contexts that cause gender differences in entrepreneurship. Specifically, this study examined the moderating effects of childbirth, a factor that reflects the social context of Korea in the relationship between gender and entrepreneurship. According to the results of the model that includes the interaction effect of these variables in addition to the independent effects of gender and childbirth, the gender effect disappeared, while the significant effect of both the childbirth variable and the interaction variable of gender and childbirth were confirmed. Furthermore, according to additional analysis, which identified the differences in entrepreneurship by creating four types of treatment groups based on gender and childbirth status, entrepreneurship was significantly lower in the 'female and childbirth' group than in all other groups. The difference between the remaining treatment groups was not statistically significant. These results indicate that differences in entrepreneurship levels between men and women overlap not with the unique trait of men and women, but with the social contextual effects of Korea, where women are under the full burden of childbirth and parenting. This study suggests implications that effective policy measures to promote women's entrepreneurship or economic activity should be taken by taking into account the social context of Korea that suppresses women's entrepreneurial behavior.

• Journal of Intelligence and Information Systems
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• v.25 no.3
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• pp.221-238
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• 2019

Recently, companies and public institutions have been actively introducing chatbot services in the field of customer counseling and response. The introduction of the chatbot service not only brings labor cost savings to companies and organizations, but also enables rapid communication with customers. Advances in data analytics and artificial intelligence are driving the growth of these chatbot services. The current chatbot can understand users' questions and offer the most appropriate answers to questions through machine learning and deep learning. The advancement of chatbot core technologies such as NLP, NLU, and NLG has made it possible to understand words, understand paragraphs, understand meanings, and understand emotions. For this reason, the value of chatbots continues to rise. However, technology-oriented chatbots can be inconsistent with what users want inherently, so chatbots need to be addressed in the area of the user experience, not just in the area of technology. The Fourth Industrial Revolution represents the importance of the User Experience as well as the advancement of artificial intelligence, big data, cloud, and IoT technologies. The development of IT technology and the importance of user experience have provided people with a variety of environments and changed lifestyles. This means that experiences in interactions with people, services(products) and the environment become very important. Therefore, it is time to develop a user needs-based services(products) that can provide new experiences and values to people. This study proposes a chatbot development process based on user needs by applying the design thinking approach, a representative methodology in the field of user experience, to chatbot development. The process proposed in this study consists of four steps. The first step is 'setting up knowledge domain' to set up the chatbot's expertise. Accumulating the information corresponding to the configured domain and deriving the insight is the second step, 'Knowledge accumulation and Insight identification'. The third step is 'Opportunity Development and Prototyping'. It is going to start full-scale development at this stage. Finally, the 'User Feedback' step is to receive feedback from users on the developed prototype. This creates a "user needs-based service (product)" that meets the process's objectives. Beginning with the fact gathering through user observation, Perform the process of abstraction to derive insights and explore opportunities. Next, it is expected to develop a chatbot that meets the user's needs through the process of materializing to structure the desired information and providing the function that fits the user's mental model. In this study, we present the actual construction examples for the domestic cosmetics market to confirm the effectiveness of the proposed process. The reason why it chose the domestic cosmetics market as its case is because it shows strong characteristics of users' experiences, so it can quickly understand responses from users. This study has a theoretical implication in that it proposed a new chatbot development process by incorporating the design thinking methodology into the chatbot development process. This research is different from the existing chatbot development research in that it focuses on user experience, not technology. It also has practical implications in that companies or institutions propose realistic methods that can be applied immediately. In particular, the process proposed in this study can be accessed and utilized by anyone, since 'user needs-based chatbots' can be developed even if they are not experts. This study suggests that further studies are needed because only one field of study was conducted. In addition to the cosmetics market, additional research should be conducted in various fields in which the user experience appears, such as the smart phone and the automotive market. Through this, it will be able to be reborn as a general process necessary for 'development of chatbots centered on user experience, not technology centered'.

• Journal of Korean Society of Disaster and Security
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• v.14 no.2
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• pp.61-75
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• 2021

Recently, as the occurrence frequency of sudden floods due to climate change increased and the aging of the existing spillway, it is necessary to establish a plan to utilize an auxiliary spillway to minimize the flood damage of downstream rivers. Most studies have been conducted on the review of flow characteristics according to the operation of auxiliary spillway through the hydraulic experiments and numerical modeling. However, the studies on examination of flood damage in the downstream rivers and the stability of the revetment according to the operation of the auxiliary spillway were relatively insufficient in the literature. In this study, the stability of the revetment on the downstream river according to the outflow conditions of the existing and auxiliary spillway was examined by using 3D numerical model, FLOW-3D. The velocity, water surface elevation and shear stress results of FLOW-3D were compared with the permissible velocity and shear stress of design criteria. It was assumed the sluice gate was fully opened. As a result of numerical simulations of various auxiliary spillway operations during flood season, the single operation of the auxiliary spillway showed the reduction effect of maximum velocity and the water surface elevation compared with the single operation of the existing spillway. The stability of the revetment on downstream was satisfied under the condition of outflow less than 45% of the design flood discharge. However, the potential overtopping damage was confirmed in the case of exceeding the 45% of the design flood discharge. Therefore, the simultaneous operation with the existing spillway was important to ensure the stability on design flood discharge condition. As a result of examining the allocation ratio and the total allowable outflow, the reduction effect of maximum velocity was confirmed on the condition, where the amount of outflow on auxiliary spillway was more than that on existing spillway. It is because the flow of downstream rivers was concentrated in the center due to the outflow of existing spillway. The permissible velocity and shear stress were satisfied under the condition of less than 77% of the design flood discharge with simultaneous operation. It was found that the flood damage of downstream rivers can be minimized by setting the amount allocated to the auxiliary spillway to be larger than the amount allocated to the existing spillway for the total outflow with simultaneous operation condition. However, this study only reviewed the flow characteristics around the revetment according to the outflow of spillway under the full opening of the sluice gate condition. Therefore, the various sluice opening conditions and outflow scenarios will be asked to derive more efficient utilization of the auxiliary spillway in th future.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.15 no.6
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• pp.135-154
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• 2020

This paper analyzes the 5,521 samples of the small and medium-sized businesses(SMBs) obtained from the Korea Credit Guarantee Fund. From January 2014 to September 2019, 85% of the SMBs have 5 or fewer full-time employees. The proportion of SMBs is overwhelmed by the elderly men, and most founders are the CEO. Also, about 87% of the workplace types are rented, while 64% of the CEO's residence types are owner-occupation. 47% of the financial grade score is less than 10 points out of 100 and 80% of SMBs have less than 200 million won of the loan guarantee. In particular, the total guarantee loan amount or the days of net guarantee have significantly positive relations with the working period of the CEO in the same industry, the number of employees, the operation period of SMBs, and the corporate business type. In the case of the financial grading score which has the highest weight in overall credit rating gets higher with the higher number of employees, the longer the operation period, and the corporate business type. However, the quantified non-financial grading score has no significant relationship with other explanatory variables, except for the corporate business type. This implies that a non-financial grade score is measured by other determinants that are not observed by the Korea credit guarantee fund. The pure non-financial grade score has positive relations with the working period of the CEO. Overall, this paper would help Korean SMBs upgrade their credit ratings and expand the money supply when there is no standardized credit rating model or no publicly available evaluation criteria for SMBs. We expect this paper provides important insights for further research and policy-makers for SMBs. In particular, to address the financial needs of thin-filers such as SMBs, technology-based financial services (TechFin) would use alternative data to evaluate the financial capabilities of thin-filers and to develop new financial services.

• The Journal of the Convergence on Culture Technology
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• v.8 no.2
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• pp.227-234
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• 2022

Seok Jeon Hwang Wook (18913~1999), a descendant of a traditional literary writer in the western part of Honam, did not join the flow of modern and contemporary calligraphy and painting. And throughout his life, he enjoyed himself without losing the appearance of a scholar, immersed himself in traditional calligraphy, and gained spotlight at his late age for his original hand grabbing calligraphy. Immediately after the Korean War, all of his property was lost due to his two sons' left-wing activities, causing great pain at home. Even in the most painful and difficult time in human history, he relied on brushes, poetry, and gayageum to keep his upright scholarly spirit and national love. And beyond the pleasures of the worldly senses, he played with self-satisfaction in the 'true pleasure(大樂)' without greed. In the course of his studies, he focused on honing the fonts of Wang Hui-ji, Gu Yang-sun, An Jin-gyeong, Jo Maeng-bu, and Xin-wi and Lee Sam-man without a special teacher. In particular, he faced a crisis of having to give up his brush due to tremor that came after his 60th birthday, but he showed a strong will. He transformed it into a new style of art, such as developing hand grabbing calligraphy(握筆法) with a strong and strong energy that no one could match. From 1965 to 1983, 'right hand grabbing calligraphy' was used, and from 1984 to 1993, 'left hand grabbing calligraphy' was used. She made her name as a calligrapher widely known in 1973 (age 76) with her first solo exhibition, The Calligraphy Exhibition commemorating her 60th wedding anniversary. His writing method is naturally rough and sloppy by breaking away from the previous calligraphy methods and artificial technique, and is unfamiliar yet full of muscle. And the calm, strong and rough chuhoegsa(錐劃沙) and the heavy yet majestic ininni(印印泥) individual handwriting expressed a strange feeling and achieved original Seokjeon calligraphy that went beyond the existing calligraphy writing methods, and his indomitable calligraphy spirit was As a unique existence in the history of calligraphy, he still remains as a model.