• Korean Journal of Food Science and Technology
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• v.41 no.2
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• pp.173-178
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• 2009

Epidemiological studies showed that high trans-fat consumption is closely associated with getting the risks of cardiovascular disease. The objective of this study was to produce trans-free fat through lipase-catalyzed interesterification, as a substitute for the cream margarine commonly used in industry. Optimum conditions for interesterification in a packed bed enzyme bioreactor (PBEB) were determined using response surface methodology (RSM) based on central composite design. Three kinds of reaction variables were chosen, such as substrate flow rate (0.4-1.2 mL/min), reaction temperature (60-70$^{\circ}C$), and ratio of fully hydrogenated canola oil (FHCO, 35-45%) to evaluate their effects on the degree of interesterification. Optimum conditions from the standpoint of solid fat content (SFC) were found to be as follows: 0.4 mL/min flow rate, 64.7$^{\circ}C$ reaction temperate, and 42.8% (w/w) ratio of FHCO, respectively. The half-life of immobilized lipase in PBEB with two stages at 60$^{\circ}C$ ($1^{st}$ stage) and 55$^{\circ}C$ ($2^{nd}$ stage) was about more than 30 days as estimated by extrapolating the incubation time course of tristearoyl glycerol (TS) conversion, whereas the half-life of the enzyme in PBEB with single stage at 65$^{\circ}C$ was only about 15 days. Finally, the results from SFC analysis suggest that trans-free fat produced in this study seems to be a suitable substitute for the cream margarine commonly used in industry.

• Journal of Biosystems Engineering
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• v.1 no.1
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• pp.1-6
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• 1976

This paper is the third one of the study on balanced type oscillating mole-drainer, the first one was presented in No 9. Gyeongsang College Report and the second one in Vol. 17, No.4 of the KSAE. In the first part of this study, the characteristics of traction forces between the nonoscillating earth working equipments and oscillating ones was compared. A model of the balanced type oscillating mole-drainer, which composed of a mechanism that may reduce the machine vibration, was designed following the dimensional analysis and similitude technique. The model test was carried out to clarify the balancing mechanism of the oscillating parts and other parts of the machine. In the light of the results from the model tests, a prototype machine was made for experimental purpose. Results from the field test by a reported in the near future. In the second report, the model tests were carried out under the same soil conditions, i.e, . oscillating frequency, running velocity, and oscillating amplitude, etc. It was clear that use of balanced type oscillating model could substantially reduce the vibration of the whole system of the machine, when compared with the nonoscillating type model. In this paper(the third report), results of investigation on the traction force, power requirement, and moment. etc, is presented. Analysis of variance technique was used for analyzing the effect of the frequency, amplitude, and running velocity on the draft force, torque, power requirements, and moments. The results obtained from the model tests are as follows, 1) By practicing a balanced-type oscillating mole-drainer, it was possible to reduce the traction resistance by 55.1-61. 2 percent of traction resistance, however, was 1.75 - 1.95 times greater than the value of resistance which was induced by use of a mole-drainer with single bullet. The resistance of rear shank against soil was considered as a main causing factor of the above results. 2) As the oscillation frequency was increased, the traction resistance was decreased. Considering on the effect of oscillation the greater the amplitude, and the slower the running velocity was, the greater the reduction ratio of traction resistance was. 3) The ratio of the traction resistance of oscillating mole-drainer to that of non-oscillating one could be represented as a function of dimensionless variable (V/$Af$). The results from the tests were well agreed with the reported results from the experim ents on oscillation plow or hoe. 4) By taking a lower value of (V/$Af$), reducing the traction resistance was possible. This fact meant, however, that the efficiency of mole drain practice would be lower. 5) It was experimentally confirmed under the same condition of soil that the variable (R/$rD1^3$) could be represented as a function of a variable($V^2/gD$) when a non\ulcornerocillating mole-drainer was used. 6) When a oscillating mole-drainer was used, the variable(R/$rD_1^{3}$) could be represented as a function of two variables ($v^2/gD_1$) and (V^2/gD_1$). 7) The torque was not affected by a change of frequency. However, a relation of proportionality existed between torque and amplitude, running velocity, and ratio of bullet diameter. When a balanced type oscillating mole-drainer with two bullets was used, torque was increased by 52.8-78. 4 percent and total power requirement was also increased. 8) Total power requirement was increased linearly in accordance with the increasing frequency, 41.96 percent of total power was used for oscillating action. The magnitude of total power requirement was 1. 8-9. 4 times greater than that of a non-oscillating mechanism. In the view point of power requirement, it was not advisable to increase the frequency, amplitude, running velocity, and ratio of bullet diameter at the same time. 9) Only the positive moment occured in the rear shank. Change of the diameter of a rear bullet, could not affect the balancing against the soil resistance. It was necessary for rear bullet to have a large resistance against soil only when the rear bullet was in backward motion. 10) Within an extent of the experimental base, optimum limits for several design factors were A=0.5cm, $f$=22.5Hz, V=O. 05m/sec, and $\lambda$=1.0 By adapting these values traction resistance was reduced by 40 percent and vibration acceleration wa s reduced by 60 percent. Even though the total , power requirements for operating a balanced type oscillation mechanism was greater ~than that of non-oscillating one, using a oscillating mechanism would be more effective. Because a balanced type oscillating mechanism is used, tractive resistance will be reduced and then the lighter . tractive equipment could be used.

• Korean journal of food and cookery science
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• v.18 no.2
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• pp.216-224
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• 2002

Persimmon powder (PW), which was prepared by pulverizing freeze-dried persimmon with peels, was added to Maejakgwa up to 25% of wheat flour. Maejakgwa samples were prepared by the central composit experimental design for three independent variables: amount of PW, frying time, and frying temperature. The color of Maejakgwa was influenced more by the frying time and temperature than the content of added PW. Crispiness and adhesiveness were highly correlated with overall preference. Although the amount of PW affected the adhesiveness, the adhesiveness could be controlled by the frying temperature and time. Frying temperature was the most effective factor on the crispness and hardness. The addition of high amount of PW obviously increased the sweetness and aftertaste. However, at the low amount of PW, frying for longer time at high temperature also increased the sweetness and aftertaste. Center sample (15% PW, frying for 4 min at 145$\^{C}$) showed the best score at the overall preference. Overall preference was improved as the sample was fried at high temperature/short time or at low temperature/long time. Maejakwa prepared with high amount of PW at 20% showed no significant difference with the center sample for overall preference as prepared by frying for 3 min at 155$\^{C}$. The optimum condition obtained by superimposing color, crispiness and overall preference was frying for 5∼6 min at 131∼140$\^{C}$.

• Journal of the Korean GEO-environmental Society
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• v.16 no.12
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• pp.45-52
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• 2015

With the rising interest in the environment, more attention on ecological restoration for damaged slope surface to restore its original state has been drawn. Generally, the most useful method is vegetation based spray work. This method uses green soil including sewage sludge, sawdust, paper sludge, and weathered granite soil. However, because there are neither accurate information nor test values about green soil, green soil is often lost by environmental factors such as rainfalls and strong winds. To solve the problem of green soil, it is necessary to prepare design standards about green soil, and conduct studies to deal with green soil loss in consideration of various variables including basic material property, soil quality of slope surface, and weather. This study was conducted in the mixture of green soil and eco-friendly soil stabilizer. With green soil, basic material property test and compaction test were conducted for the analysis on the basic characteristics of green soil. In the mixture with soil stabilizer at a certain ratio, we conducted shear strength test depending on the ratio in order to analyze the maximum shear strength, cohesion and the change in internal friction angles. Furthermore, in the mixture ratio of green soil and soil stabilizer, which is the same as the ratio in the shear strength test, an inclination of slope surface was made in laboratory for the analysis on erosion and germination rate. Finally, this study evaluated the most effective and economic mixing ratio of soil stabilizer to cope with neighboring environmental factors. According to the test, the shear strength of green soil increased up to 51% rely onto the mixing ratio of and a curing period, and its cohesion and internal friction angle also gradually increases. It is judged that the mixture of soil stabilizer was effective in improving shear strength and thereby increased the stability of green soil.

• Child Health Nursing Research
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• v.19 no.2
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• pp.85-93
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• 2013

Purpose: The study purposes were to describe the process of developing the Korean versions of the Six Dimension Scale of Nursing Performance (Six-D) and Student Nurse Stress Index (SNSI) and psychometric evaluation of the two measurements. Methods: This was a methodology study using a descriptive cross-sectional design with 51 nursing students in 4th year of university. Internal consistency reliability was assessed using Cronbach alphas. Construct validity was determined by exploring correlations among Six-D, SNSI, objective structured clinical examination (OSCE), self-efficacy and grade point average (GPA). Results: Internal consistency reliability of Six-D and SNSI was acceptable with Cronbach's ${\alpha}$ of .95 and .82. Correlation analysis to determine construct validity revealed that Six-D presented positive correlations with OSCE (r=.109~.272) and self-efficacy (r=.005~.161) and negative correlation with GPA (r=-.246~-.394), although all were not statistically significant. SNSI presented all negative correlations with OSCE (r= -.007~-.238), self-efficacy (r=-.246~-.394), and GPA (r=-.092~-.426) and were mostly statistically significant except OSCE. Conclusion: Six-D needs more evidence to confirm validity to predict observed clinical competency and theoretical relationships with self-efficacy and GPA. However, SNSI presented trends of expected relationships with relevant variables. Therefore, further research is recommended in testing validity of Six-D with other student populations.

• Korean Journal of Environment and Ecology
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• v.30 no.2
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• pp.185-198
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• 2016

Korea has put in significant efforts to increase the number of wildlife crossings between fragmented habitats to prevent loss of biodiversity and to encourage the habitat connectivity in Korea. However, there is a lack of biological data on the effect of vegetation structure in these wildlife crossings and guidelines for design and management of wildlife crossing structures in Korea. Therefore, we selected ground beetle assemblages as model organisms to compare the effect of vegetation structure in wildlife crossings, i.e. bare ground- and shrub-type corridors, in agro-forested landscapes. For this study, 4,207 ground beetles belonging to 33 species were collected through pitfall trapping along the northern forest-corridor-southern forest transects from late April to early September in 2015. Dominant species, abundance, and species richness of ground beetles were significantly higher in the shrub-type corridors than the bare ground-type corridors. Also, the species composition of bare ground-type corridor was significantly different compared to the other habitats such as shrub-type corridor and forests. Similarly, environmental variables were also influenced by vegetation management regimes or trap locations. Collectively, our study clearly indicates that the movement of forest associated ground beetles between forest patches can increase as the vegetation in wildlife crossings becomes complex. Although further studies are needed to verify this, there are indications that the current wildlife crossings that comply with the guidelines may be unfriendly to the movement of ground dwelling arthropods as well as ground beetles. To enhance the ecological function of wildlife crossings, the guidelines need to be rectified as follows: 1) Shrubs or trees should be planted along the corridor verges to provide refuge or movement paths for small mammals and ground dwelling arthropods, and 2) Open spaces should be provided in the middle of the corridors to be used as a path for the movement of large mammals.

• The Journal of Society for e-Business Studies
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• v.21 no.3
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• pp.51-78
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• 2016

Online-to-offline (O2O) commerce is the new trend that merges online commerce with traditional industries in various fields. The primary purpose of this paper is to find out which factors influence customers' intention to switch from call-based driver-for-hire services to O2O app-based services. This study used variables and factors based on Theory of Switching Intention, and Extended Unified Theory of Acceptance and Use of Technology in order to design research questions. We surveyed 500 users of call-based driver-for-hire services. According to the result of this study, dissatisfaction with the current call-based driver-for-hire services is estimated to be a significant factor that strengthens customers' intention to switch from the call-based driver-for-hire services to the app-based services. Loyalty to the previous call-based driver-for-hire services was not seen as a crucial motivator that causes customers to switch to the new O2O driver service. Switching cost also did not play a key role in explaining the relationship between dissatisfaction with the current call-based service and the intention to use the new app-based service. Performance expectancy, easiness in use, the level of user's knowledge or available assistance in relation to the use of app-based services, and expectancy for reasonable price was found to have meaningful impacts on customers' intention to switch from the call-based driver-for-hire services to the app-based services. Age, gender and user experience on the new service were found incapable of moderating the relationship between aforementioned factors which influence customers' choice of the app-based driver-for-hire service, and customers' intent to switch to the app-based service.

• Journal of the Korean Institute of Landscape Architecture
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• v.44 no.6
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• pp.148-161
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• 2016

In the case of the government, which plays a pivotal role in the landscape architecture system, the management of positions in landscape architectural organizations is lacking. At the local government level, while public officials for managing landscape architecture are being hired, there are problems and vulnerabilities in both management and system operations as such public officials recruited for positions in landscape architectural services operate under the forestry service. Accordingly, this study analyzed the Korean administrative system of public officials in the landscape architectural service and their satisfaction with the organizational culture and behavior. The aim was to provide practical data for improving the job satisfaction of public officials in landscape architectural service and enhance the status of landscape architecture. First, a survey was conducted regarding current organizational culture/behavior and job adequacy, and differences when compared to different job series with regards to the public officials in the landscape architectural service. The results indicated that job satisfaction of those in landscape architectural service was generally high, but they showed strong centralization, i.e., orders from superiors and limitations on autonomy. Second, an analysis was conducted to improve the organizational culture/behavior and job satisfaction of public officials in the landscape architectural service, and a comparative analysis was conducted on the differences between the analysis result and preceding studies by the Ministry of Government Administration and Home Affairs(2006). The results indicated that organizational commitment/satisfaction of public officials in the landscape architectural service was relatively low among those who had a great amount of work experience related to forestry. Therefore, it was shown that it is necessary to ensure expertise in landscape architecture. Third, a comprehensive analysis was conducted regarding the influences on "working environment", "legal system" and "job allocation" in regard to public officials in land architectural service. The results indicated that satisfaction in the value system was high when given significance to the job as public officials in land architectural. However, their satisfaction in the land architectural system was low due to the lack of independence in their positions, the vulnerable legal system of land architectural service and low employment rates. Fourth, current public officials in landscape architectural service process tasks such as forestry, architecture, city planning and administration that are not related to their area of expertise. Therefore, an analysis was conducted on whether there is a difference in the job satisfaction of public officials in landscape architectural service according to statistical variables. It was identified that "legal system", "job satisfaction" and "organizational commitment" with regard to public officials in landscape architectural service can be improved through ensuring their expertise. This study suggests the following tasks to further inquire into landscape architecture in general. First, establish an identity of work allocation for public officials in the landscape architectural service, and second, establish an organizational constitution according to the positions in landscape architectural service. Accordingly, it is necessary for interested parties of landscape architecture to devise practical strategies so that such tasks can be converged administratively and reflected in policies.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.5
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• pp.549-557
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• 2006

The characteristics of supercritical water oxidation have been studied to decompose the waste anionic exchange resins which were produced from a power plant. The waste resins from a power plant were mixture of anionic and cationic exchange resins. The waste anionic exchange resins had been separated from the waste resins using a solid-liquid fluidized bed. It was confirmed that the cationic exchange resins were not included in the separated anionic exchange resins by the elemental and thermogravimetric analysis. A slurry of anionic exchange resins which could be fed continuously to a supercritical water oxidation apparatus by a high pressure pump was prepared using a wet ball mill. Although the COD of liquid effluent had been reduced more than 99.9% at 25.0 MPa and $500^{\circ}C$ within 2 min, the total nitrogen content was reduced only 41%. The addition of nitric acid to the slurry could reduce the total nitrogen content in treated water. The central composite design as a statistical desist of experiments had been applied to optimize the conditions of decomposing anionic resin slurry by means of the COD and total nitrogen contents in treated waters as the key process output variables. The COD values of treated waters had been reduced sufficiently to $99.9{\sim}100%$ af the reaction conditions of $500{\sim}540^{\circ}C$, 25.0 MPa within 2 min. The effects of temperature and nitric acid concentration on COD were not significant. However, the effect of nitric acid concentration on the total nitrogen was found to be significant. The regression equation for the total nitrogen had been obtained with nitric acid concentration and the coefficient of determination($r^2$) was 95.8%.

• Journal of the Korean Applied Science and Technology
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• v.37 no.3
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• pp.473-483
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• 2020

This paper proposes a tourism recommendation system in intelligent cloud environment using information of tourist behavior applied with perceived value. This proposed system applied tourist information and empirical analysis information that reflected the perceptual value of tourists in their behavior to the tourism recommendation system using wide and deep learning technology. This proposal system was applied to the tourism recommendation system by collecting and analyzing various tourist information that can be collected and analyzing the values that tourists were usually aware of and the intentions of people's behavior. It provides empirical information by analyzing and mapping the association of tourism information, perceived value and behavior to tourism platforms in various fields that have been used. In addition, the tourism recommendation system using wide and deep learning technology, which can achieve both memorization and generalization in one model by learning linear model components and neural only components together, and the method of pipeline operation was presented. As a result of applying wide and deep learning model, the recommendation system presented in this paper showed that the app subscription rate on the visiting page of the tourism-related app store increased by 3.9% compared to the control group, and the other 1% group applied a model using only the same variables and only the deep side of the neural network structure, resulting in a 1% increase in subscription rate compared to the model using only the deep side. In addition, by measuring the area (AUC) below the receiver operating characteristic curve for the dataset, offline AUC was also derived that the wide-and-deep learning model was somewhat higher, but more influential in online traffic.