• Communications for Statistical Applications and Methods
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• v.16 no.3
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• pp.449-461
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• 2009

Higher sigma quality level is generally perceived by customers as improved performance by assigning a correspondingly higher satisfaction score. The process capability indices and the sigma level $Z_{st}$ ave been widely used in six sigma industries to assess process performance. Most evaluations on process capability indices focus on statistical estimation under normal process which may result in unreliable assessments of process performance. In this paper, we consider statistical estimation for bivariate VPCI(Vector-valued Process Capability Index) $C_{pkl}=(C_{pklx},\;C_{pklx})$ under Marshall and Olkin (1967)'s bivariate exponential process. First, we derive some limiting distribution for statistical inference of bivariate VPCI $C_{pkl}$. And we propose two asymptotic normal confidence regions for bivariate VPCI $C_{pkl}$. The proposed method may be very useful under bivariate exponential process. A numerical result based on our proposed method shows to be more reliable.

• Water for future
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• v.26 no.1
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• pp.115-124
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• 1993

This study is to determine the critical duration of design rainfall and to utilize it for the design of detention pond with pump station. To examine the effect of the duration and temporal distribution of the design rainfall, Huff's quartile method is used for the 9 cases of durations ranging from 20 to 240 minutes with 10 years return period, and the ILLUDAS model is used for runoff analysis. The storage ration which is the ratio of maximum storage amounts to total runoff volume, is introduced to determine the critical duration of design rainfall. The duration which maximizes the storage ratio is adopted as the critical duration. This study is applied to 18 urban drainage watersheds with pump station in Seoul, of which the range of watershed area is $0.24-12.70\textrm{km}^2.$ The result of simulation shows that the duration which maximizes storage ration is 30 and 60 minutes on the whole. It is shown also that the storage ration of 2nd- and 3rd-quartile pattern is larger than that of 1st- and 4th-quartile pattern of temporal distribution. A simplified empirical formula for Seoul area is suggested by using the regression analysis between the maximum storage ration and the peak ratio, and can be utilized for the preliminary design and planning of detention pond with pump station.

• The Journal of Society for e-Business Studies
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• v.18 no.4
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• pp.215-240
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• 2013

This research has reviewed the major composition concepts and the positive research results in the selected studies which were theoretically based on IDT (Innovation Diffusion Theory), IRM (Model of Innovation Resistance), TAM(Technology Acceptance Model), and IAPA(Information Asset Protection Activity) in order to improve the theoretical explanation of major characterized factors influencing on the introduction of MST (Mobile Security Technology). The characterized factors for the adaptation of MST and 17 hypotheses on the MST study models in order to test the effects on the intention to use are empirically verified by utilizing the analysis method of structure equation model. As a result of a study, First, the most influential characterized factors of IRM are shown as compatibility, complexity, relative advantage, information asset protection in order. Second, the characterized factors affecting intention to use are shown as relative advantage, compatibility, innovation resistance, performance expectancy. The results of this study are relevantly significant to establish the theoretical foundation of the study on the adaptation of MST and The verification of the characterized factors provide strategic implication for the introduction of MST and policy direction which alleviates informational gap between new MST and previous Security Technology to diffusion agency.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.17 no.1
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• pp.17-30
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• 2018

Currently, the global climate change response paradigm has been changed to a universal response system in which all nations, not the developed countries, participate. Korea has also set a target of 25.9 million tons of transportation greenhouse gas reduction targets by 2030. Korean society is expected to enter the super aging society in 2026. In this study, to reduce the greenhouse gas emissions in public transport and to improve the convenience of transportation vulnerable, we estimate the willingness to pay(WTP) and social benefits assuming that the existing feeder buses are replaced with medium-sized low floor electric buses. To this end, survey was conducted on bus users in the metropolitan area and WTP was estimated by using contingent valuation method(CVM), which is one of the non-market value evaluation methods. As a result of estimation of WTP, the average WTP is 51.4 (won / time person), estimated the economic benefits were 50 million won on weekdays and 40 million won on weekends in Gyeonggi Province in 2014.

• Journal of the Korean GEO-environmental Society
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• v.10 no.3
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• pp.37-45
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• 2009

The experimental study was carried out to evaluate the characteristics of the point load index and the uniaxial compressive strength of inherently anisotropic shale in the laboratory. In the testing program the effects of size and the shape on the point load index were investigated both in the axial and diametral direction. In general, the point load index of the shale was constant when the length/diameter (L/D) ratio of the specimen is greater than 1.0 in the diametral direction. The point load index in axial direction shows slight decrease as the L/D ratio is increased and the corner breakage was observed when L/D ratio is greater than unity. The minimum point load index was observed in the bedding angle of $\beta=15^{\circ}{\sim}30^{\circ}$ in the axial point load tests and of $\beta=30^{\circ}$ in the uniaxial compression tests. The relationship between the point load index and the uniaxial compressive strength was linear to ${\sigma}_c=25.0 I_{s(50)}$ for the specimen with the bedding plane angle, $\beta$ at the range of $0^{\circ}{\sim}90^{\circ}$. On the other hand, this relationship was appeared linear to ${\sigma}_c=14.4 I_{s(50)}$ when the bedding angle, $\beta$ is fixed to 90${^{\circ}}$ and this correlation is much different from ${\sigma}c=22 I_{s(50)}, which is generally applied to the rock specimen with no bedding plane in ISRM (1985). The anisotropic strength with different $\beta$ angle shows the shoulder type and this can be suitably modelled by the corrected Ramamurthy'(1993)s equation with the index value of 'n' equal to 3.0.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.2 no.1
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• pp.93-104
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• 1982

DTM data evaluation regards accuracy and efficiency as its most important parameters, and these two elements are sensitively influenced by the sampling technique employed and its procedure. This study attempts to improve sampling techniques and evaluate the accuracy of DTM based on earth volume calculation, using aerial photography and field survey information as basic DTM data, and a regular grid and progressive sampling method for sampling process. Especially, the progressive sampling has employed different combinations of threshold and sampling criteria, that is, parameters influential on efficiency and accuracy, for the purpose of numerical tests intended to permit comparative analysis. The tests have resulted in the findings that in progressive sampling its grid density fits in well with given terrain characteristics in proportion to their variability. and that threshold and accuracy contain close mutual relations in which an increased threshold bringing more efficency but less accuracy. It follows, therefore. that a threshold, when appropriately determined, can be of very efficient use for considerably broad applications, and particularly, will play a significant role in its application to such general civil engineering as earth volume calculation.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.7 no.3
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• pp.13-21
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• 1987

The object of this study was to evaluate the management alternatives with respect to the attainable water quality and total cost(construction+O & M cost) in order to devise a reasonable water quality management system. Joong Ryang-cheon stream located Seoul, Korea was taken as the study area, and dissolved oxygen concentration as the water quality index. Water quality simulation model QUAL2E and linear programming optimization technique were used for scientific and rational analyses. It was assumed that the improvement of water quality could be obtained by the treatment of major point sources where imaginary treatment plants were constructed. And by this, the relationship between total cost of the treatment plants and the stepwise improvement of water quality was studied. The result showed that 3.5mg/l of DO(=dissolved oxygen) level at best could be attained in Joong Ryang-cheon stream during summer. When the DO standard was set 3.0mg/l in the severely polluted regions, more than 5.0mg/l of DO level can be achieved by the construction of 4 treatment plants. Also, the cost comparisons showed that the uniform treatment method is economically inefficient(\$24.8{\times}10^8$) in comparison with the least cost method(\$22.9{\times}10^8$), and there is little difference between the least cost method and the the zoned treatment method(\$23.0{\times}10^8$) that is regarded as more equitable, which shows the characteristics of this basin.

• Journal of Digital Convergence
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• v.15 no.8
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• pp.161-168
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• 2017

The purpose of this study is to investigate the effect of restaurant selection factors on reliability and revisit intention. The results of empirical analysis were as follows: First, the factors influencing the intention to visit the restaurant were the physical environment, service, price, location, reputation, cleanliness, It is confirmed that consumers are willing to visit again if their satisfaction is high because they choose general consumers considering kindness and taste. Second, trust is found to affect re - visit intention and it can be judged that store faith is actively considering return visit through consumer 's belief. Third, it was found that the factor of selecting the restaurant business influenced the intention to visit again according to the trust. When the customer chooses according to the restaurant business standard and satisfies the trust, it intends to increase the intention to visit again. The results of this study are as follows. First, it is found that the factors of restaurant selection and trust affect the revisit intention of restaurants, and it is meaningful to provide theoretical and strategic implications.

• Information Systems Review
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• v.11 no.1
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• pp.19-47
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• 2009

Many products today tend to adopt a convergence approach by adding new features or functionalities to the existing products. The convergence, however, results in both positive and negative effects on usage of products, and thus demonstrates the characteristics called "paradox of technology." On the one hand, the added functionalities or features will increase the usefulness of the products. On the other hand, the convergence increases complexity of learning and usage of products and may decrease satisfaction or user evaluations. This study provides an empirical evidence of this paradox through investigation of telematics, one of the exemplary products of convergence services. Our research model is designed to test the existence of the "paradox of technology" and includes variables such as variety of functions, complexity of usage, perceived usefulness, service evaluation, and service fit. The proposed research model and subsequent hypotheses are empirically tested using 149 survey responses from telematics users. We have found that the variety of functions is positively associated with perceived usefulness, but is negatively associated with the complexity of usage. The data analysis reveals that the perceived usefulness has more significant impacts on service evaluation than the complexity of usage does. Furthermore, the strength of causal relationships among these variables is partially moderated by the degree of service fit. This study thus highlights the paradox of technology in explaining user attitudes and beliefs associated with convergence services.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.12 no.2
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• pp.41-54
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• 2017

The purpose of this study is to find out how the support system of the government and the local governments for enhancing the success rate of the startup firms affected the performance of the enterprises according to the behavior characteristics of the founders. It is divided entrepreneurial support system into entrepreneurial policy support such as entrepreneurial education, mentoring and consulting, and funding of startup support such as policy fund and R & D fund, distinguished the behavior of founder into behaviors for discovery of entrepreneurial opportunities and behaviors for exploiting entrepreneurial opportunities. In order to analyze whether it affects the corporate management performance, a research model was created based on the previous research and hypotheses were set up, and the hypotheses were verified based on this questionnaire. The results of this study are as follows: First, it is found that the support for entrepreneurial policy has a positive effect on the behavior characteristics of entrepreneur. Second, it is found that the startup support such as policy fund affects the behavioral characteristics for finding the opportunity of the founder, but it does not affect the behavioral characteristics for the opportunity exploit. Third, it was found that the behavior characteristics of entrepreneur founding opportunity and exploition of entrepreneurial opportunity influenced the performance of the company. According to the this study, the following conclusion were obtained, First, it is necessary to apply different policies according to the stage of growth of startup companies. Second, startup companies grow through the stages of development of new technologies and ideas, commercialization, and marketing, at each stage, entrepreneur must overcome the so-called Death Valley, which requires funding.