• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.12 no.9
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• pp.843-852
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• 2000

The flow characteristics and the heat transfer rate on a surface by interaction of a pair of vortices were studied experimentally. The test facility consisted of a boundary-layer wind tunnel with a vortex introduced into the flow by half-delta winglet protruding from the surface. In order to control the strength of the longitudinal vortices, the angles of attack of the vortex generators were varied from $\pm20\;degree\;to\;\pm45$ degree, but spacings between the vortex generators were fixed to 4 cm. The 3-dimensional mean velocity measurements were made using a five-hole pressure probe. Heat transfer measurements were made using the thermochromatic liquid to provide the local distribution of the heat transfer coefficient. By using the method mentioned above, the following conclusions were obtained from the present experiment. The boundary layer was thinned in the regions where the secondary flow was directed toward the wall and thickened where it was directed away from the wall. The peak augmentation of the local heat transfer coefficient occurred in the downwash region near the point of minimum boundary-layer thickness.

• Journal of Korean Public Health Nursing
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• v.13 no.2
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• pp.70-83
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• 1999

This study was designed to evaluate the prevalence and significant features of accidental patients and to evaluate the degree of satisfaction on emergency care who visited emergency room. The subject of this study was a total of 243 accidental patients and 249 patients with disease visiting emergency room of 4 university hospitals in Seoul. The data was collected from guestionnaire during the period of January to february 1999. The results were summarized as follows. 1. Distribution of the general characteristics (age, sex, educational status, marrital status and job) in the accidental patients were significantly different from that of the control group. The most common group of age was 20-30 years of age and males predominated over female. 2. CD Fourty two $\%$ of accidental patients arrived within 30 mins. (2) Fifty seven $\%$ of patients was first-aided one. (3) An ambulance was the most frequently used transportation. (4) The time interval from arrival to initial emergency care was 10 mins. (5) Admission rates of the patients after treatment was $72.0\%$. (6) Time interval from arrival to completion was 3-4 hours. 3. The Mean score of the accidental patents' degree of satisfaction on emergency services was $3.26\pm0.64$ which was not significantly different from that of control group.

• Journal of Korean Society for Quality Management
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• v.46 no.3
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• pp.717-738
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• 2018

Purpose: This study aims to analyze why surveys of a single set of customer requirement result in different Kano analyses depending on the survey questionnaire designs. Methods: This study singled out 14 common features from four different questionnaires of two studies of Smart Car features and analyzed them using the Kano model. Several methods and devices were used: Group Comparison and Timko Index were applied; Kano Distribution Index, Timko Dispersion and Kano Conformity were newly introduced for the quantitative analysis; Correlations between Timko indices from different Kano questionnaires were conducted; Heuristic Splitting technic for reinforcing attribute categorization is introduced. Results: Correlation Coefficient proved strong positive relations among the three questionnaires, whose agreement degree of the resulting Kano attributes showed less than 10% when Indifferent was ignored. Heuristic Splitting on Timko charts enhanced the degree of the resulting Kano attributes up to 80%. Conclusion: Among the questionnaires the representation of customer requirements tends to move by parallel shifts on the Timko chart maintaining their relative locations. Heuristic Splitting suggests a rational solution to the interpretation of those inexplicable attribute categories resulting from traditional Kano methods.

• Journal of Soil and Groundwater Environment
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• v.21 no.6
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• pp.128-134
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• 2016

Acoustic emission spectra was analyzed to investigate the distribution of sound pressure in a 36 kHz sonoreactor. The sound pressure of fundamental frequency (f: 36 kHz), harmonics (2f: 72 kHz, 3f: 108 kHz, 4f: 144 kHz, 5f: 180 kHz, 6f: 216 kHz), and subharmonics (1.5f: 54 kHz, 2.5f: 90 kHz, 3.5f: 126 kHz, 4.5f: 162 kHz, 5.5f: 198 kHz, 6.5f; 234 kHz) was measured at every 5 cm from the ultrasonic transducer using a hydrophone and a spectrum analyzer. It was revealed that the input power of ultrasound, the application of mechanical mixing, and the concentration of SDS affected the sound pressure distributions of the fundamental frequency and total detected frequencies frequencies significantly. Moreover a linear relationship was found between the average total sound pressure and the degree of sonochemical oxidation while there was no significant linear relationship between the average sound pressure of fundamental frequency and the degree of sonochemical oxidation.

• Journal of the Korean Society of Visualization
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• v.14 no.1
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• pp.19-26
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• 2016

Modern people spend much time at indoor space. So, People want to make better indoor air condition. But the facade of building is made of glass to be seen urbanely, the effect of solar radiation makes indoor environment worse. This study designs an open space affected by solar radiation with 4-way cassette air-conditioner. Using numerical simulation, this paper investigates thermal comfort and ventilation performance with discharge angles $30^{\circ}$ and $45^{\circ}$. To study thermal comfort, this paper studies distribution of velocity, temperature and effective draft temperature. Also, this paper introduces concept of air age to study ventilation performance. The flow influenced by solar radiation determines thermal comfort and ventilation performance in room space. This study shows that discharge angle of 45 degree has better thermal comfort and ventilation performance than that of 30 degree.

• The Journal of Asian Finance, Economics and Business
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• v.2 no.1
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• pp.5-13
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• 2015

This paper aims to provide an overview of customer trust toward Islamic banks, and to study the effect of trust on the selection of Islamic banks services. A total 375 questionnaires were distributed to the three groups of bank customers, i.e. Islamic banks customers, conventional banks customers, and customers of both banks (125 respondents in each group). Trust is measured based on three constructs, namely Ability, Integrity, and Benevolence. To test the hypothesis this study employs Analysis of Variance and Tukey Test. The results show that bank customers have degree of trust towards Islamic banks relatively high enough, although among the respondents had never become customers of Islamic banks. Benevolence as the dimension with the lowest average score revealed the Islamic banks are more believed as a competent and honest bank in carrying out the business than the bank that will work for the benefit of customers. Other findings suggest that degree of trust have significant affects on the decision for using the Islamic banks services. The positive values that embedded in the concepts and systems of the Islamic is the key to improving the competitiveness of Islamic banks.

• The Journal of Asian Finance, Economics and Business
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• v.7 no.1
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• pp.239-247
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• 2020

Technological convergence is yielding new values and affecting various fields not by single technology but by convergence between technologies. This study aims to analyze the IT -BT-NT convergence and differences between technologies in respect of collaboration within (inventor) and between (assignee) organizations. Among the main technologies leading the technological convergence, IT is the most active of converging with other fields. BT is knowledge-intensive and strong cooperative networks are important in this area. NT is applied in various industrial fields upon the basic technology. Using the data on applied and granted patents by Korean applicants in the U.S., this study conducted quantitative analysis and ANOVA to gain the following results. First, the degree of convergence in between IT-BT-NT is continuously increasing since 2002. Second, BT is where the collaboration within and between organizations is the most active among IT-BT-NT. Third, there were certain differences in the degree of convergence according to the years and the fields of technologies in all the IT-BT-NT. Organizations cooperate with other institutions to sustain their competitiveness with limited internal resources. Companies in these fields are recommended to perform diverse strategies to pursue further collaboration with the outside.

• Journal of Korean Society of Rural Planning
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• v.23 no.2
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• pp.9-17
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• 2017

Rural development policy has changed from hardware based development to community revitalization. The purpose of this study is to analyze social network of collaborative activity among rural organizations as fundamental of community. The material used in this study is a record of collaborative activites in the community newsletter of Hong-Dong area. 161 of collaborative activities (links) and 75 of organizations (nodes) are investigated in network. 6 collaborative activity type ('Education', 'Socializing', 'Meeting', 'Culture', 'Event' and 'Labor') is classified. 'Socializing' is inclusive of approximately half of whole network (50.67%). Closeness centraization, degree centralization and betweenness centralization are measured on top in 'Education', 'Meeting' and 'Event' type. Scatter plot analysis using degree and betweenness centrality index, 'Maeul Revitalization Center', 'Balmak Library', 'Woori-Maeul Medical Co-op', 'Support Center for Female Farmers', 'Hongdong Middle School' and 'Mundang Sustainable Agriculture Education Center' are resulted as the core organization in network. Geographical distribution of collaborative activity is not only concentated in Hong-Dong Myeon but also networked with adjacent administrative district. This study finds its purpose in the detailed analysis of network characteristics of collaborative activity within Hong-Dong area which is representative developed rural community in Korea.

• Communications for Statistical Applications and Methods
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• v.17 no.1
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• pp.9-16
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• 2010

The sampling design for the spatial population studies needs a model assumption of a dependent relationship, where the interesting parameters can be the population mean, proportion and area. We know that the study of an interested spatial population, which is stratified by a geographical condition or shape, and the degree of distort of an estimation area is much useful. In light of this, if auxiliary information of the target variable such as wasted area contaminated by some material and the degree of distribution of animal or plants is available, then the spatial estimator might be improved through the calibration procedure. In this research, we propose the calibration procedure for the spatial stratified sampling in which we consider the one and two-dimensional auxiliary information.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.29 no.2 s.233
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• pp.180-188
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• 2005

It is well known that a lean burn engine caused by stratified mixture formation has many kinds of advantages to combustion characteristics, such as higher thermal efficiency and lower CO, NOx levels than conventional homogeneous mixture combustion. Although this combustion can achieve low fuel consumption technology, it produces much unburned hydrocarbon and soot because of heterogeneous equivalence ratio in the combustion chamber. Therefore, the stratified mixture formation technology is very important to obtain the stable lean combustion. In this paper, fundamental studies for stratified combustion were carried out using a constant volume combustion chamber. The local effect of mixture formation according to control air-fuel distribution in the chamber was examined experimentally. In addition, the effect of turbulence on stratified charge combustion process was observed by schlieren photography. From this study, we found that the flame propagation speed increase with swirl flow and the swirl promotes the formation of fuel and air mixture.