• Korean Journal of Poultry Science
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• v.50 no.2
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• pp.91-99
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• 2023

This study aimed to develop a high-productivity breed of Korean native Samgye chicken. We evaluated the production performance of six Korean native chicken combinations (KNC-SCYC, SCYD, SDYC, SDYD, SYYC, SYYD) and GSP-Hanhyup Korean native chickens, with Baeksemi chickens used as a control group. The performance test was conducted from hatching to 7 weeks of age on 756 chickens, and we measured survival rate, body weight, shank length, feed utility, and carcass yield. The overall survival rate was nearly 100% for all strains. However, body weight showed significant differences between strains at all ages (P<0.01), with Baeksemi weighing 863.8±76.9 g, GSP-Hanhyup weighing 804.7±72.5 g, and KNC-combinations weighing 543.0±61.8 g at 5 weeks of age. The duration needed to reach 850 g was estimated to be 34.5 days for Baeksemi, 37.5 days for GSP-Hanhyup, and 45.8-48.8 days for KNC-combinations. Carcass yield percentage was highest for KNC-SYYD combination at 63.3%, followed by Baeksemi at 60.4%, and GSP-Hanhyup at 56.1%. Shank length at 850 g body weight was 7.6 cm for KNC-SYYD combination, 7.8 cm for Baeksemi, and 8.0 cm for GSP-Hanhyup. The feed conversion ratio at 850 g body weight was 1.81 for Baeksemi, 2.17 for GSP-Hanhyup, and 2.27 for KNC-SCYC combination. Our results suggest that the KNC-SYYD combination and GSP-Hanhyup breed have the potential to be used in Samgye production due to their moderate growth performance, higher carcass yield, and shorter shank length, despite their lower growth productivity and feed efficiency when compared to Baeksemi.

• 한국노년학
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• v.29 no.3
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• pp.837-850
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• 2009

Previous epidemiological studies reported that significant muscle loss is observed with advancing aging, called sarcopenia. This study is to investigate the effects of treatment dumbbell exercise on prevention of sarcopenia. The subjects were elderly between 60~70 years old who participated in J-Welfare senior center exercise program at J-gu in S-city and divided into control group(N=19) and exercise group(N=8). Treatment dumbbell exercise was performed 2 times per week for 12 weeks and body composition, fitness, and blood lipid profiles were measured before and after this program. There was no significance in body fat before and after 12 weeks of treatment dumbbell exercise, but there was significance in weight(F=4.312, p=0.048), BMI(F=4.532, p=0.043), and FFM(F=4.743, p=0.039). There was no significance in fitness such as arm curl(F=1.103, p=0.304), and back scratch(F=0.214, p=0.648), but there was significance in 2-minute step(F=33.638, p<0.001), chair stand(F=14.575, p=0.001), chair sit and reach(F=7.198, p=0.013), and 8-ft up and go(F=14.890, p=0.001). The variables of blood lipid profiles such as TC(F=0.030, p=0.864), TG(F=0.142, p=0.710), HDL(F=2.066, p=0.163), glucose (F=0.125, p=0.727), and HbA1c(F=0.945, p=0.340) has no significance. It was found that treatment dumbbell exercise has positive effects on body composition and fitness but has no positive effects on blood lipid profiles of the elderly.

• 한국노년학
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• v.29 no.4
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• pp.1559-1575
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• 2009

As the basic old-age pension system was enforced in 2008, the base for old-age income security was founded. However, due to the basic old-age pension played a minor role as assistant allowance, it did not reach to sufficient level to cover full income security system. It is estimated that the dependency on private transfer income among the elderly who are difficult to be economically independent is still high. Therefore the poverty rate of the elderly households, who are not economically active or who are not protected by old-age income security system, is more likely to be higher than that of non-elderly households. Based on the assumption that public transfer income system should become a central means of old-age life guarantee, this study examined the poverty mitigation effects among the elderly households by comparing the private transfer income and the public transfer income. For this purpose, we selected single-elderly-households who have been considered the most vulnerable to poverty. We used 2006- 2008 Household Income and Expenditure Survey dataset that contained single-elderly who were older than 65 years old. To understand the conditions of poverty among single-elderly-households and the degree of poverty-reducing effect originated from income transfer system, we compared the poverty rates of total households and the whole elderly households. Next, we analysed the poverty of the single-elderly-households by social demographic factors such as gender, age, and economic activity. Our major findings are as follows: First, the poverty rate of the whole elderly households were not reduced, even though the basic old-age pension and long-term care management system were enforced in 2008. Second, half of the elderly households including single-elderly-households belonged to the absolute poverty line. Relatively higher level of poverty among the single-elderly-households was found especially those who were female, unemployed, low-educated, older, and rural single-elderly-households. Third, the effect of the public transfer income on mitigating the single-elderly-households poverty showed a little progress. However, even greater poverty reducing effect was found by the private transfer income system. Fourth, in a group of the public transfer systems, the public assistance such as supporting living costs contributed more to reduce poverty of the elderly population than the public pension system did.

• Korean small business review
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• v.31 no.1
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• pp.73-88
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• 2009

This study examines the characteristics of 24 Korean hidden champions such as key success factors, core competences, strategic problems, and desirable future directions. The study categorized them into 8 types with Danny Miller's four trajectories and top manager's decision making style(rationality and passion). Danny Miller argued in his book, Icarus paradox, that outstanding firms will extend their orientations until they reach dangerous extremes and their momentum will result in common trajectories of decline. He suggested four very common success types: Craftsmen, Builders, Pioneers, Salesmen. He also suggested common trajectories of decline:Focusing(from Craftsmen to Tinkers), Venturing(from Builders to Imperialists), Inventing(from Pioneers to Escapists), Decoupling(from Salesmen to Drifts). In Korea, successful startups appear to possess three kinds of drive: Technology-drive, Vision-drive, Market-drive. Successful technology-driven firms tend to grow as craftsmen or pioneers. Successful vision-driven and market-driven ones tend to grow as builders and salesmen respectively. Korean top managers or founders seem to have two kinds of decision making style: Passion-based and Rationality-bases. Passion-based(passionate) entrepreneurs are biased towards action or proactiveness in competing and getting things done. Rationality- based ones tend to emphasis the effort devoted to scanning and analysing information to better understand a company's threats, opportunities and options. Consequently this study suggested 4*2 types of Korean hidden champions: (1) passionate craftsmen, (2) rational craftsmen, (3) passionate builders, (4) rational builders, (5) passionate pioneers, (6) rational pioneers, (7) passionate salesmen, (8) rational salesmen. These 8 type firms showed different success stories and appeared to possess different trajectories of decline. These hidden champions have acquired competitive advantage within domestic or globally niche markets in spite of the weak market power and lack of internal resources. They have maintained their sustainable competitiveness by utilizing three types of growth strategy; (1) penetrating into the global market, (2) exploring new service market, (3) occupying the domestic market. According to the types of growth strategy, these firms showed different financial outcomes and possessed different issues for maintaining their competitiveness. This study found that Korean hidden champions were facing serious challenges from the transforming economic structure these days and possessed the decline potential from their success momentum or self-complacence. It argues that they need to take a new growth engine not to decline in the turbulent environment. It also discusses how firms overcome the economic crisis and find a new business area in promising industries for the future. It summarized the recent policy of Korean government called as "Green Growth" and discussed how small firms utilize such benefits and supports from the government. Other implications for firm strategies and governmental policies were discussed.

• Journal of The Korean Society of Grassland and Forage Science
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• v.43 no.4
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• pp.216-224
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• 2023

Since maize (Zea mays L.) originated in central and south America, it requires warm climate conditions throughout its growing season. Growth halts when night-time temperatures drop below 10℃, and the plant may die if temperature reach -1.7℃. Thus, temperature should be maintained between 10 and 30℃ from seeding to maturity. The germination temperature for maize should be at least 8-11℃, whit an optimal range 32-34℃. Since temperature significantly affects the germination rate and period, it plays a crucial role in maize growth. In this study, we evaluated the quantity and feed value of 11 major varieties to determine those best suited for maize cultivation as feed in higher latitude, specifically in Democratic People's of Republic of Korea, below 38 degrees north. A cultivation test was also conducted in Suwon in Republic of Korea, to assess adaptability in areas south of Mt. Suyang. Among the varieties tested, Shinhwangok2 reached silking the fastest, in 65 days, while Gwangpyeongok took the longest at 75 days. The stem length of all varieties exceeded 230 cm. Gwangpyeongok had the tallest stems, while Daanok and Shinhwangok2ho displayed the highest ear ratios. Dacheongok presented the highest values in both dry matter and TDN quantity, with 31,420 kg/ha and 21,66 kg/ha respectively. Pyeonggangok had the highest crude protein content at 8.0%. TDN (%) ranged from 57-68%, with Hwangdaok reaching up to 68%. Based on these findings, Dacheongok and Pyeonggangok appear to be the most suitable varieties for cultivation in terms of both quantity and feed value.

• Korean Journal of Remote Sensing
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• v.39 no.5_4
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• pp.1173-1183
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• 2023

Over the past 20 years, Korea's overall import and export cargo volume has increased at an average annual rate of approximately 5.3%. About 99% of the cargo is still being transported by sea. Due to recent increases in maritime cargo volume, congestion in maritime logistics has become challenging due to factors such as the COVID-19 pandemic and conflicts. Continuous monitoring of ports has become crucial. Various ground observation systems and Automatic Identification System (AIS) data have been utilized for monitoring ports and conducting numerous preliminary studies for the efficient operation of container terminals and cargo volume prediction. However, small and developing countries' ports face difficulties in monitoring due to environmental issues and aging infrastructure compared to large ports. Recently, with the increasing utility of artificial satellites, preliminary studies have been conducted using satellite imagery for continuous maritime cargo data collection and establishing ocean monitoring systems in vast and hard-to-reach areas. This study aims to visually detect ships docked at berths in the Busan New Port using high-resolution satellite imagery and quantitatively evaluate berth utilization rates. By utilizing high-resolution satellite imagery from Compact Advanced Satellite 500-1 (CAS500-1), Korea Multi-Purpose satellite-3 (KOMPSAT-3), PlanetScope, and Sentinel-2A, ships docked within the port berths were visually detected. The berth utilization rate was calculated using the total number of ships that could be docked at the berths. The results showed variations in berth utilization rates on June 2, 2022, with values of 0.67, 0.7, and 0.59, indicating fluctuations based on the time of satellite image capture. On June 3, 2022, the value remained at 0.7, signifying a consistent berth utilization rate despite changes in ship types. A higher berth utilization rate indicates active operations at the berth. This information can assist in basic planning for new ship operation schedules, as congested berths can lead to longer waiting times for ships in anchorages, potentially resulting in increased freight rates. The duration of operations at berths can vary from several hours to several days. The results of calculating changes in ships at berths based on differences in satellite image capture times, even with a time difference of 4 minutes and 49 seconds, demonstrated variations in ship presence. With short observation intervals and the utilization of high-resolution satellite imagery, continuous monitoring within ports can be achieved. Additionally, utilizing satellite imagery to monitor changes in ships at berths in minute increments could prove useful for small and developing country ports where harbor management is not well-established, offering valuable insights and solutions.

• Journal of Venture Innovation
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• v.5 no.1
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• pp.59-73
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• 2022

Untact marketing is being activated due to COVID-19. As a result, live commerce, an untact seller, is also active in the e-commerce market. Therefore, in this study, we tried to find out what factors influence consumers when they purchase through live commerce. In particular, since consumers' trust and flow in live commerce platforms and products is important, their mediating effects were analyzed. The research model was established by deriving common variables among the characteristics of live commerce based on previous studies. An online survey was conducted for empirical analysis. 200 users who made at least one purchase in live commerce were analyzed. The study results are as follows. Among the characteristics of live commerce, entertainment, economics, professionality were found to have a positive (+) effect on purchase intention. On the other hand, ease of use did not significantly affect purchase intention. The influence was shown in the order of entertainment, professionality and economics. The mediating effect of trust was found to play a mediating role in that entertainment, economics, and professionality affect purchase intention. On the other hand, a significant mediating effect was not tested between ease of use and purchase intention. As for the mediating effect of flow, it was found that flow plays a mediating role in that entertainment and economics affect purchase intention. On the other hand, the mediating effect of flow in terms of ease of use and economics affecting purchase intention was not tested. As for the multiple mediating effect of flow and trust, the mediating effect of flow was stronger than the mediating effect of trust when entertainment had an effect on purchase intention. In terms of professionality affecting purchase intention, the mediating effect of flow was also stronger than the mediating effect of trust. On the other hand, it was analyzed that only trust had a mediating effect when economics had an effect on purchase intention. The results of this study empirically tested that entertainment, which is a fun and interesting factor of live commerce content, is the most important factor when consumers use live commerce. In addition, various results were derived, such as cases where trust and flow act as mediators at the same time or not at all. Practical implications can be found in that it provided a clue about what to prioritize in order to reach consumers for live commerce platform.

• Journal of the Korean Institute of Gas
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• v.27 no.3
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• pp.52-58
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• 2023

With the increasing awareness of the importance of carbon neutrality in response to global climate change, the utilization of hydrogen as a carbon-free fuel source is also growing. Hydrogen is commonly used in fuel cells (FC), but it can also be utilized in internal combustion engines (ICE) that are based on combustion. Particularly, ICEs that already have established infrastructure for production and supply can greatly contribute to the expansion of hydrogen energy utilization when it becomes difficult to rely solely on fuel cells or expand their infrastructure. However, a disadvantage of utilizing hydrogen through combustion is the potential generation of nitrogen oxides (NOx), which are harmful emissions formed when nitrogen in the air reacts with oxygen at high temperatures. In particular, for the EURO-7 exhaust regulation, which includes cold start operation, efforts to reduce exhaust emissions during the warm-up process are required. Therefore, in this study, the characteristics of nitrogen oxides and fuel consumption were investigated during the warm-up process of cooling water from room temperature to 88℃ using a 2-liter direct injection spark ignition (SI) engine fueled with hydrogen. One advantage of hydrogen, compared to conventional fuels like gasoline, natural gas, and liquefied petroleum gas (LPG), is its wide flammable range, which allows for sparser control of the excessive air ratio. In this study, the excessive air ratio was varied as 1.6/1.8/2.0 during the warm-up process, and the results were analyzed. The experimental results show that as the excessive air ratio becomes sparser during warm-up, the emission of nitrogen oxides per unit time decreases, and the thermal efficiency relatively increases. However, as the time required to reach the final temperature becomes longer, the cumulative emissions and fuel consumption may worsen.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.17 no.4
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• pp.115-125
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• 2022

In today's era when the concept of a lifelong job has disappeared, starting a business is an essential consideration for university students not only as an alternative factor in finding employment, but also from the perspective of the entire life. Today, most universities in Korea are operating entrepreneurship education programs, such as entrepreneurship classes as a curriculum, and start-up clubs as a non-curricular program to foster entrepreneurship among university students. In previous studies, entrepreneurship is a factor influencing the entrepreneurship intention. The purpose of this study is to empirically examine the effects of university students' entrepreneurship and the entrepreneurship intention through a entrepreneurship education program (participation in a start-up club, taking an entrepreneurship course) on entrepreneurship behavior. There are some empirical studies on whether entrepreneurship education programs such as participation in startup contests affect the entrepreneurship intention of university students, but not much compared to their importance. It is difficult to find an empirical study examining the effects of entrepreneurship and start-up education programs on entrepreneurship intention and entrepreneurship behavior in domestic and foreign studies. Therefore, in this study, one domestic university that operates a start-up club and a entrepreneurship course was selected and the online questionnaire was distributed to all current students, and the collected 127 questionnaires were used for empirical analysis As a result of the study, first, it was confirmed that initiative and risk-taking, which are sub-factors of entrepreneurship of university students, had a significant positive effect on entrepreneurial intention, respectively, and that innovation did not have a significant positive effect. Second, it was confirmed that university students' participation in a start-up club, a sub-factor of the start-up education program, had a significant positive effect on their entrepreneurial intention, and that taking a start-up course did not have a significant positive effect. Third, it was confirmed that the entrepreneurial intention of university students had a significant positive effect on entrepreneurship behavior. Fourth, it was confirmed that the entrepreneurial intention had a mediating effect between each of the factors of risk-taking, and participation in a start-up club and entrepreneurial behavior. This study suggests that university students can increase their risk-taking, increase their entrepreneurial intention by participating in a startup club, and reach a entrepreneurial behavior through this as a medium.

• Korean Journal of Radiology
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• v.2 no.1
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• pp.28-36
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• 2001

Objective: To provide a systematic overview of the effects of various parameters on contrast enhancement within the same population, an animal experiment as well as a computer-aided simulation study was performed. Materials and Methods: In an animal experiment, single-level dynamic CT through the liver was performed at 5-second intervals just after the injection of contrast medium for 3 minutes. Combinations of three different amounts (1, 2, 3 mL/kg), concentrations (150, 200, 300 mgI/mL), and injection rates (0.5, 1, 2 mL/sec) were used. The CT number of the aorta (A), portal vein (P) and liver (L) was measured in each image, and time-attenuation curves for A, P and L were thus obtained. The degree of maximum enhancement (Imax) and time to reach peak enhancement (Tmax) of A, P and L were determined, and times to equilibrium (Teq) were analyzed. In the computed-aided simulation model, a program based on the amount, flow, and diffusion coefficient of body fluid in various compartments of the human body was designed. The input variables were the concentrations, volumes and injection rates of the contrast media used. The program generated the time-attenuation curves of A, P and L, as well as liver-to-hepatocellular carcinoma (HCC) contrast curves. On each curve, we calculated and plotted the optimal temporal window (time period above the lower threshold, which in this experiment was 10 Hounsfield units), the total area under the curve above the lower threshold, and the area within the optimal range. Results: A. Animal Experiment: At a given concentration and injection rate, an increased volume of contrast medium led to increases in Imax A, P and L. In addition, Tmax A, P, L and Teq were prolonged in parallel with increases in injection time The time-attenuation curve shifted upward and to the right. For a given volume and injection rate, an increased concentration of contrast medium increased the degree of aortic, portal and hepatic enhancement, though Tmax A, P and L remained the same. The time-attenuation curve shifted upward. For a given volume and concentration of contrast medium, changes in the injection rate had a prominent effect on aortic enhancement, and that of the portal vein and hepatic parenchyma also showed some increase, though the effect was less prominent. A increased in the rate of contrast injection led to shifting of the time enhancement curve to the left and upward. B. Computer Simulation: At a faster injection rate, there was minimal change in the degree of hepatic attenuation, though the duration of the optimal temporal window decreased. The area between 10 and 30 HU was greatest when contrast media was delivered at a rate of 2 3 mL/sec. Although the total area under the curve increased in proportion to the injection rate, most of this increase was above the upper threshould and thus the temporal window was narrow and the optimal area decreased. Conclusion: Increases in volume, concentration and injection rate all resulted in improved arterial enhancement. If cost was disregarded, increasing the injection volume was the most reliable way of obtaining good quality enhancement. The optimal way of delivering a given amount of contrast medium can be calculated using a computer-based mathematical model.