• Asian Journal of Turfgrass Science
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• v.20 no.2
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• pp.191-201
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• 2006

Dollar spot caused by Sclerotinia homeocarpa is one of major diseases in putting greens. Microorganisms antagonistic to S. homeocarpa, a pathogen of dollar spot, were primarily screened through in vitro tests, including dual culture method and triple layer agar diffusion method. In vivo tests were also conducted to select the best candidate for a biocontrol microorganism, using pot experiment. Bacillus subtilis EW42-1 and Trichoderma harziaum GBF-0208 were finally selected as biocontrol agents against dollar spot. Relative Performance Index(RPI) was used as a criterion of selecting potential biocontrol agents. B. subtilis EW42-1 and T. harzianum GBF-0208 showed resistance to several agrochemicals mainly used in a golf course. B. subtilis EW42-1 and T. harzianum GBF-0208 suppressed effectively the disease progress of dollar spot like synthetic fungicide tebuconazole in the nursery where dollar spot had seriously occurred. B. subtilis EW42-1 and T. harzianum GBF-0208 have a potential to be biocontrol agents for the control of dollar spot.

• Korean Journal of Applied Biomechanics
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• v.21 no.5
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• pp.521-528
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• 2011

The purpose of this study was to analyze the kinematic characteristics of the finalists in the women's 100 m event to provide important information to coaches and athletes. Three different biomechanics techniques were applied for analyzing sprinter motion: LAVEG, a panning technique, and 12 video cameras for 3 dimensional analysis of the 40 m - 70 m portion of the race. Carmelita Jeter(USA) performed the maximum speed of 10.54 m/s at the distance of 58.2 m. There was a tendency to show a better performance time with a high number of steps (p=.13) and shorter stride length (p=.14) among the 8 sprints. Furthermore, the stride frequency and the performance time were negatively correlated as a higher stride frequency had a positive impact on the performance time (p=.02). Based on 3 dimensional analysis, the 4 top ranked sprinters used the different strategies to maintain a high COM (Center of Mass) velocity during the mid portion of the race (40 m - 70 m). Carmelita Jeter(USA) showed more flexed knee and hip motion at heel contact (HC) to maintain a high COM velocity while S.A. Fraser-Pryce (JAM) showed more extended knee and hip motion at HC. On the other hands, Veronica Campbell-Brown (JAM) and Kelly-Ann Baptiste (TRI) showed a tendency to have high knee lifts during the swing phase to maintain the high COM velocity during the race. These biomechanical analyses of the women's 100 m final event in the 2011 WC, Daegu, will provide important scientific information to coaches and athletes for understanding the sprinting mechanism of today's top-class sprinters.

• The Journal of the Korea Contents Association
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• v.13 no.12
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• pp.48-61
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• 2013

At the dawn of a new digital era, people's way of spending their leisure time and leisure activity preferences changed. Accordingly, Leisure culture is in the midst of change, such as watching movie and performance, enjoy golf etc. Due to its nature as an interactive medium, the digital game offers uniquely different approaches to the leisure activity. Leisure as state of mind is much more subjective in that it considers the individual's perception of an activity. In that regard, we used the digital games for leisure activity. Digital games are powerful environments for fun, including functional nature. For that reason digital leisure culture keep creative evolving. This paper proposes a serious games as a branch of digital games that meaningful digital leisure, and introduced the concept of serious games for a serious purpose other than pure entertainment. Many recent studies have identified the benefits of using serious games in a variety of purposes. Games technology is fun and entertaining for people of all ages. Ultimately, serious games become meaningful and valuable performance tools as the Digital Leisure Culture.

• Journal of Intelligence and Information Systems
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• v.24 no.2
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• pp.243-264
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• 2018

Although the worldwide battery market is recently spurring the development of lithium secondary battery, lead acid batteries (rechargeable batteries) which have good-performance and can be reused are consumed in a wide range of industry fields. However, lead-acid batteries have a serious problem in that deterioration of a battery makes progress quickly in the presence of that degradation of only one cell among several cells which is packed in a battery begins. To overcome this problem, previous researches have attempted to identify the mechanism of deterioration of a battery in many ways. However, most of previous researches have used data obtained in a laboratory to analyze the mechanism of deterioration of a battery but not used data obtained in a real world. The usage of real data can increase the feasibility and the applicability of the findings of a research. Therefore, this study aims to develop a model which predicts the battery deterioration using data obtained in real world. To this end, we collected data which presents change of battery state by attaching sensors enabling to monitor the battery condition in real time to dozens of golf carts operated in the real golf field. As a result, total 16,883 samples were obtained. And then, we developed a model which predicts a precursor phenomenon representing deterioration of a battery by analyzing the data collected from the sensors using machine learning techniques. As initial independent variables, we used 1) inbound time of a cart, 2) outbound time of a cart, 3) duration(from outbound time to charge time), 4) charge amount, 5) used amount, 6) charge efficiency, 7) lowest temperature of battery cell 1 to 6, 8) lowest voltage of battery cell 1 to 6, 9) highest voltage of battery cell 1 to 6, 10) voltage of battery cell 1 to 6 at the beginning of operation, 11) voltage of battery cell 1 to 6 at the end of charge, 12) used amount of battery cell 1 to 6 during operation, 13) used amount of battery during operation(Max-Min), 14) duration of battery use, and 15) highest current during operation. Since the values of the independent variables, lowest temperature of battery cell 1 to 6, lowest voltage of battery cell 1 to 6, highest voltage of battery cell 1 to 6, voltage of battery cell 1 to 6 at the beginning of operation, voltage of battery cell 1 to 6 at the end of charge, and used amount of battery cell 1 to 6 during operation are similar to that of each battery cell, we conducted principal component analysis using verimax orthogonal rotation in order to mitigate the multiple collinearity problem. According to the results, we made new variables by averaging the values of independent variables clustered together, and used them as final independent variables instead of origin variables, thereby reducing the dimension. We used decision tree, logistic regression, Bayesian network as algorithms for building prediction models. And also, we built prediction models using the bagging of each of them, the boosting of each of them, and RandomForest. Experimental results show that the prediction model using the bagging of decision tree yields the best accuracy of 89.3923%. This study has some limitations in that the additional variables which affect the deterioration of battery such as weather (temperature, humidity) and driving habits, did not considered, therefore, we would like to consider the them in the future research. However, the battery deterioration prediction model proposed in the present study is expected to enable effective and efficient management of battery used in the real filed by dramatically and to reduce the cost caused by not detecting battery deterioration accordingly.

• Journal of the Ergonomics Society of Korea
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• v.36 no.3
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• pp.183-196
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• 2017

Objective: The purpose of this research was to assess the agreement between job physical risk factor analysis by ergonomists using ergonomic methods and physical examinations made by occupational physicians on the presence of musculoskeletal disorders of the upper extremities. Background: Ergonomics is the systematic application of principles concerned with the design of devices and working conditions for enhancing human capabilities and optimizing working and living conditions. Proper ergonomic design is necessary to prevent injuries and physical and emotional stress. The major types of ergonomic injuries and incidents are cumulative trauma disorders (CTDs), acute strains, sprains, and system failures. Minimization of use of excessive force and awkward postures can help to prevent such injuries Method: Initial data were collected as part of a larger study by the University of Utah Ergonomics and Safety program field data collection teams and medical data collection teams from the Rocky Mountain Center for Occupational and Environmental Health (RMCOEH). Subjects included 173 male and female workers, 83 at Beehive Clothing (a clothing plant), 74 at Autoliv (a plant making air bags for vehicles), and 16 at Deseret Meat (a meat-processing plant). Posture and effort levels were analyzed using a software program developed at the University of Utah (Utah Ergonomic Analysis Tool). The Ergonomic Epicondylitis Model (EEM) was developed to assess the risk of epicondylitis from observable job physical factors. The model considers five job risk factors: (1) intensity of exertion, (2) forearm rotation, (3) wrist posture, (4) elbow compression, and (5) speed of work. Qualitative ratings of these physical factors were determined during video analysis. Personal variables were also investigated to study their relationship with epicondylitis. Logistic regression models were used to determine the association between risk factors and symptoms of epicondyle pain. Results: Results of this study indicate that gender, smoking status, and BMI do have an effect on the risk of epicondylitis but there is not a statistically significant relationship between EEM and epicondylitis. Conclusion: This research studied the relationship between an Ergonomic Epicondylitis Model (EEM) and the occurrence of epicondylitis. The model was not predictive for epicondylitis. However, it is clear that epicondylitis was associated with some individual risk factors such as smoking status, gender, and BMI. Based on the results, future research may discover risk factors that seem to increase the risk of epicondylitis. Application: Although this research used a combination of questionnaire, ergonomic job analysis, and medical job analysis to specifically verify risk factors related to epicondylitis, there are limitations. This research did not have a very large sample size because only 173 subjects were available for this study. Also, it was conducted in only 3 facilities, a plant making air bags for vehicles, a meat-processing plant, and a clothing plant in Utah. If working conditions in other kinds of facilities are considered, results may improve. Therefore, future research should perform analysis with additional subjects in different kinds of facilities. Repetition and duration of a task were not considered as risk factors in this research. These two factors could be associated with epicondylitis so it could be important to include these factors in future research. Psychosocial data and workplace conditions (e.g., low temperature) were also noted during data collection, and could be used to further study the prevalence of epicondylitis. Univariate analysis methods could be used for each variable of EEM. This research was performed using multivariate analysis. Therefore, it was difficult to recognize the different effect of each variable. Basically, the difference between univariate and multivariate analysis is that univariate analysis deals with one predictor variable at a time, whereas multivariate analysis deals with multiple predictor variables combined in a predetermined manner. The univariate analysis could show how each variable is associated with epicondyle pain. This may allow more appropriate weighting factors to be determined and therefore improve the performance of the EEM.

• Asian Journal of Turfgrass Science
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• v.18 no.3
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• pp.149-163
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• 2004

Physical and chemical properties of root zone mixes and methods of green construction are important considerations for improving turf grass quality for putting greens. This study compared Penncross creeping bentgrass (Agrostis palustris Huds.) performance as affected by three root zone construction systems with three amendments (sand, peat, and zeolite). The objective of this study was to determine if an amended California construction system would improve green performance during establishment (1998-1999) and maturation (2000-2001). Three treatments were tested: California ($100\%$ sand), USGA($90\%$ sand and $10\%$ peat, v/v), and California-Z ($85\%$ sand and $15\%$ zeolite, v/v). Treatments were arranged in a randomized complete block with four replicates. Physical and chemical properties of the root zone and bentgrass performance were compared for the treatments. The California-Z treatment had the highest saturated hydraulic conductivity, field infiltration rate and the lowest bulk density. It also had the highest cation exchange capacity and plant available nutrient concentrations among the three treatments. The California-Z treatment produced bentgrass quality and color during green establishment and maturation that were equal to or higher than the California treatment, and consistently higher than the USGA treatment. The addition of an inorganic amendment to the California system improved physical and chemical properties of the root zone and improved quality and color of bentgrass during green establishment. During green maturation, creeping bentgrass in the California-Z treatment was equal (6 of 15 sampling dates) or $20\%$ higher (9 of 15 dates) in quality compared to the California system.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.10
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• pp.272-279
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• 2018

This study was conducted to compare the muscle strength, muscle power, and H/Q ratio according to energy system contribution in athletes participating in various sports. Subjects of the study were assigned into an Anaerobic Exercise Group (AEG, n=60; Short-Distance, Weight Lifting, Jumping, Throwing, Bowling, Golf) and an Endurance Exercise Group (EEG, n=60; Modern Pentathlon, Field Hockey, Handball, Cycle, Boxing, Rowing) groups. Isokinetic peak torque/body weight% and flexor/extensor ratio at 60, 180 deg/sec of knee extension and flexion were measured using an cybex 770. Data analysis was conducted using an independent t-test and one-way ANOVA. Based on the results of this study, there was higher extension, flexion strength and flexion power in the AEG than the EEG (p<0.05). We also confirmed higher muscle strength and muscle power in short distance and jumping athletes than other athletes participating in other events (p<0.05). However, there was no significant difference within the endurance exercise group. The HS ratio was within a stable range of 50% to 60% in all events. Collectively, the outcomes of this study indicate that routine physiological and performance testing can provide measurable benefits for elite athletes and their coaches.

• The Journal of the Korea Contents Association
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• v.9 no.11
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• pp.407-415
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• 2009

In this research, to identify the degree of preference and participation in leisure sports, over 19-year-old adults living in the capital region were collected as subjects, and among them, 250 persons were chosen by purposive sampling method. Using SPSSWIN 16.0, I analyzed the collected data by reliability analysis, paired sample t-test, PPA(preference performance analysis) method. The conclusion is the following. First, the first quadrant showed wind surfing, skins-cuba, water-ski, and yacht, and as a result of this, it is necessary to improve the degree of participation in this field, the second quadrant showed golf, racketball snow board, ski, fishing, and climbing, and these field need to specific attention to maintain continuous attention, for they have a great deal of attendance, the third quadrant, showed water sleigh, cart, balloon, sky-diving, orienteering, hang gliding, model plane, and survival game. As the degree of preference and participation in these sports is low, it is recommended that more effort should be made for these sports. Finally, in the forth quadrant, there are tracking, mountain bike, inline skates, rafting, and cycling. As it's the participation is high, while that of preference is low, it is important to maintain the policy of the participation in leisure sports. Sencondly, the degree of preference and participation in leisure sport activicties acording to socio demographic characteristics differentiate.

• Asian Journal of Turfgrass Science
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• v.23 no.1
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• pp.35-44
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• 2009

This study was carried out to examine the growth performance of 4 species of cool-season grasses and 4 species of zoysiagrasses under salt injury in Seo-san reclaimed area. Grasses were grown on the plots with capillary water interruption layer (WCWIL) and without capillary water interruption layer (WOCWIL) soil systems. Cool-season grass and seeding-type zoysiagrass plots were seeded on 6 Jun, 2006. Vegetative zoysiagrass 'Junggi' was established by sprigging and 'Senock' and 'Millock' were plugged. Electric conductivities of irrigation water (ECw) ranged from 0.28 to $3.3\;dS{\cdot}m^{-1}$. Electric conductivities (ECe) of the soil with capillary water interruption layer and without capillary water interruption layer ranged from 0.55 to $9.4\;dS{\cdot}m^{-1}$ and from 1.84 to $9.4\;dS{\cdot}m^{-1}$ respectively. Leaf color, turf quality, coverage rates, and growth rates were rated visually for 2 years. Zoysiagrass 'Junggi', creeping bentgrass, zoysiagrass 'Senock' and 'Millock' showed acceptable growth at salty fairway condition, while Kentucky bluegrass, perennial ryegrass, Kentucky bluegrass mixed with perennial ryegrass, and seeded zoysiagrass 'Zenith' showed establishment rates below 70%. These results will be useful when choosing turf grass species and cultivars for the golf courses in reclaimed land area.

• Asian Journal of Turfgrass Science
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• v.22 no.2
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• pp.149-160
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• 2008

This study was carried out to examine the growth performance of 10 cultivars of creeping bentgrass under salt injury in Seo-san reclaimed area. Turfgrass performance studies included 10 creeping bentgrass cultivars (T-1, L-93, Penn A1, Pennlinks II, Seaside II, Declaration, Penn A4, Crenshaw, Dominant, and Penncross). Ten creeping bentgrass cultivars were grown on a USGA recommended research green. Plots were seeded on May 31, 2006 at the rate of $7\;g{\cdot}m^{-1}$. Electric conductivities of irrigation water (ECw) and soil (ECe) were ranged from 0.28 to $3.3\;d\;S{\cdot}m^{-1}$ and from 0.25 to $3.5\;d\;S{\cdot}m^{-1}$ respectively. Leaf color, turf quality, coverage rate, and growth rate were checked under the salty condition in reclaimed land for 2 year. Creeping bentgrass cultivars of T-1, Penn links, and Crenshaw presented dark green color and Penn A1, Declaration showed lighter green color. Penn A1, Penn A4 and L-93 exhibited the highest overall turfgrass quality. Average visual coverage was 75.3% after eleven weeks after seeding. Dominant, L-93, and Penn A1 resulted in higher visual coverage compared to the other cultivars. There was no difference in density among cultivars at 1 year after establishment. However, Declaration, Penn A1, T-1, and L-93 showed higher density compared to the other cultivars at 2 years after seeding. Creeping bentgrass showed different quality, density and color in salty soil (ECe: $0.25-3.5\;d\;S{\cdot}m^{-1}$) and from application of salty irrigation water (ECw: $0.28-3.3\;d\;S{\cdot}m^{-1}$) conditions. These results will be useful where selecting green cultivars for the golf courses in reclaimed land area.