• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.6
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• pp.88-97
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• 2018

Computer modeling and optimization works have been performed for the separation of the binary mixture of 1-propanol and benzene through a pressure-swing distillation. PRO/II with PRIVISION V10.0 at Schneider Electric company and NRTL liquid activity coefficient model were utilized. The sum of the total reboiler heat duties of the low-high and high-low pressure column configurations were compared. To minimize the utility consumptions, low column, and high column to obtain pure benzene at the top, the number of theoretical stages and optimal feed tray locations for each distillation column were determined and the reflux ratios for each distillation column were also adjusted. As a result of the optimization works, the sum of the total reboiler heat duties for the high-low and low-high pressure configurations were $3.10{\times}10^6kcal/h$ and $2.75{\times}10^6kcal/h$, respectively. In the case where heat integration was applied to low-high pressure configurations, 57.36 % of the total reboiler heat duties could be saved compared to the high-low pressure configurations.

• Membrane Journal
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• v.5 no.1
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• pp.35-43
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• 1995

For several years lots of attempts have been made to establish the liquid membrane-based techniques for separations of gas mixtures especially containing carbon dioxide. A more effective system to separate $CO_{2}$ from flue gases, a circulatory hollow-fiber membrane absorber(HFMA) consisting of absorption and desorption modules with vacuum mode, has been considered in this study. Gas-liquid mass transfer has been modeled on a membrane module with non-wetted hollow-fibers in the laminar flow regime. The influence of an absorbent flow rate on the separation performance of the circulatory HFMA can be predicted quantitatively by obtaining the $CO_{2}$ concentration profile in a tube side. The system of $CO_{2}/N_{2}$ binary gas mixture has been studied using pure water as an(inert) absorbent. As the absorbent flow rate is increased, the permeation flux(i.e., defined as permeation rate/membrane contact area) also increases. The enhanced selectivity compared to the previous results, on the other hand, shows the decreasing behavior. It has been found obviously that the permeation flux depends on the variations of pressure in gas phase of desorption module. From an accurate comparison with the results of conventional flat sheet membrane module, the advantageous permeability of this circulatory HFMA can be clearly ascertained as expected. Our efforts to the theoretical model will provide the basic analysis on the circulatory HFMA technique for a better design and process.

• The Journal of the Korea Contents Association
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• v.19 no.11
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• pp.122-131
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• 2019

This study analyzed the moderating effect according to school levels in the structural relationship between stressful interpersonal relationships at work and rumination in teachers' depression. For this study, a research model was formed based on theoretical understandings and a literature review. The researchers surveyed 811 teachers at primary and secondary schools to measure scales of depression, rumination, and stress in interpersonal relationships at work. Primary education and secondary education were the grouping variables for the school levels, and the collected data was analyzed using multi-group structural equation modeling. Also, to affirm equivalence between the two models, the data was investigated using the constrained model of measurement equivalence. The research results verified the equivalence between the two models and the moderating effect by comparing the path coefficients of the two models on the assumption of equivalence constraint. As a result, the moderating effect according to school levels was revealed on the path from stressful interpersonal relationships at work to depression. Grounded on this analysis, stress in interpersonal relationships at work mediates the impact of rumination in teachers' depression. In addition, the research revealed that the moderating effects on stressful interpersonal relationships at work varied according to school level, and the moderating effect of stress in interpersonal relationships at work affected middle school teachers but not primary school teachers.

• Environmental and Resource Economics Review
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• v.23 no.2
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• pp.187-224
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• 2014

We present key issues to consider in estimating damages from price-fixing cases and then apply the procedure addressing those issues to a transportation fuel market. Among the five methods of overcharge calculation, the regression analysis incorporating the yardstick method is the best. If the price equation relates the domestic price to the foreign price and the exchange rate as in the transportation fuel market, the functional form satisfying both logical consistency and modeling flexibility is the log-log functional form. If the data under analysis is of time series in nature, then the ARDL model should be the base model for each market and the regression analysis incorporating the yardstick method combines these ARDL equations to account for inter-market correlation and arrange constant terms and collusion-period dummies across component equations appropriately so as to identify the overcharge parameter. We propose a two-step test for the benchmarked market: (a) conduct market-by-market Spearman or Kendall test for randomness of the individual market price series first and (b) then conduct across-market Friedman test for homogeneity of the market price series. Statistical significance is the minimal requirement to establish the alleged proposition in the world of uncertainty. Between the sensitivity analysis and the model selection process for the best fitting model, the latter is far more important in the economic analysis of damage in price-fixing litigation. We applied our framework to a transportation fuel market and could not reject the null hypothesis of no overcharge.

• Journal of Service Research and Studies
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• v.7 no.4
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• pp.109-126
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• 2017

Designing cost-effective service recovery strategies mix has been recognized one of important issues by both service researchers and practitioners. In spite of the rising interest in them, there has been scarce studies on them. In this paper, we try to find cost-effective service recovery strategies mix via game-theoretic modeling. Especially, we focus on the possible incentives such as voucher type reward and service re-performance which have different cost structure. We investigated three questions about the topics as follows:(1) Should the service firm use the possible incentive scheme such as voucher and service re-performance for service recovery?, (2) How much voucher and service re-performance is adequate for service recovery under diverse service failure severity level?, (3) How much voucher and service re-performance is adequate for service recovery under diverse threshold level to make the customer repurchase? The results are as follows:(1) The use of both voucher and service re-performance for service recovery results in greater surplus for the service firm. (2) The higher gets the service failure severity level, the higher total incentives are required in the equilibrium. As service failure severity level gets higher, higher level of discount might be more useful to the service firm. However, service re-performance should be cut down above some critical level of service failure severity in the equilibrium. (3) The higher gets the threshold level to make the customer repurchase, the higher incentives are required in the equilibrium, and the higher portion of voucher incentive is required relative to that of service re-performance in the equilibrium.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.19 no.4 s.74
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• pp.429-440
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• 2006

This paper comprises two specific objectives. The first is to examine the applicability of ordinary kriging interpolation(OK) to the p-adaptivity of the finite element method that is based on variogram modeling. The second objective Is to present the adaptive procedure by the hierarchical p-refinement in conjunction with a posteriori error estimator using the modified S.P.R. (superconvergent patch recovery) method. The ordinary kriging method that is one of weighted interpolation techniques is applied to obtain the estimated exact solution from the stress data at the Gauss points. The weight factor is determined by experimental and theoretical variograms for interpolation of stress data apart from the conventional interpolation methods that use an equal weight factor. In the p-refinement, the analytical domain has to be refined automatically to obtain an acceptable level of accuracy by increasing the p-level non-uniformly or selectively. To verify the performance of the modified S.P.R. method, the new error estimator based on limit value has been proposed. The validity of the proposed approach has been tested with the help of some benchmark problems of linear elastic fracture mechanics such as a centrally cracked panel, a single edged crack, and a double edged crack.

• Journal of Distribution Science
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• v.11 no.1
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• pp.25-34
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• 2013

Purpose - This study examines the adverse press coverage that has increased in proportion to the remarkable growth of various kinds of franchise businesses in the food service industry. Today, the trust of franchisees in relation to their franchisor, and the maintenance of good relations between the two, has become a significant social issue. This study investigates relationship satisfaction and the long-term commitment between the franchisor and franchisee. Research design, data, methodology - We used a path analysis to investigate the relationship between justice and trust, trust and relationship satisfaction, justice and relationship satisfaction, trust and long-term commitment, and relationship satisfaction and long-term commitment. Structural Equation Modeling and a Sobel test were used to investigate the mediating effects of trust and relationship satisfaction. Data were collected from 237 Food Franchisees in Seoul and Gyeonggi Province in order to test the theoretical model and its hypotheses. Two research methodologies are generally used in the distribution management field. For this study, an empirical method was used. Results - A causal analysis was carried out to test if the research model has a sufficient fit index (for instance, χ² = 46.694, df = 10, p = .000, GFI = 0.946, AGFI = 0.850, RMR = 0.034, NFI = 0.966, CFI = 0.973), and the results showed that the model was sufficient, thus demonstrating the suitability of the research model. Each hypothesis had a positive influence, both on long-term commitment and relationship satisfaction. Justice with the franchisor had a positive influence on trust. Relation satisfaction cognized by franchisees was found to positively influence long-term commitment. The franchisee perception of justice in relation to the franchisor had no significant influence on long-term commitment. The study investigated the hypothesis that trust could mediate justice and long-term commitment, and that relationship satisfaction could also mediate long-term commitment Both trust and relationship satisfaction were found to be important for long-term commitment. Specifically, trust sub-factors and justice sub-factors influenced long-term commitment. Identification-based and knowledge-based trust were more important than calculus-based trust. Distributive justice was deemed more important than procedural justice; distributive justice should thus be strengthened. Conclusions - Both franchisor and franchisee were independent businesses. Evidently however, the franchisor could not ensure profit without long-term commitment from the franchisee. As for the success of the franchise business, the franchisor should carry out appropriate strategies leading to a satisfactory relationship. For example, transparency makes it possible to maintain and enhance trust and to improve relationship satisfaction. Just relations between franchisor and franchisee should make it possible to maintain and enhance the franchisee's trust. The franchisor should provide a variety of information with respect to the franchisee's business success. Finally, in order to improve the franchisee's long-term commitment, the franchisor should ensure a just approach with trust and relationship satisfaction among their strategies.

• Journal of the Korean Association of Geographic Information Studies
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• v.10 no.2
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• pp.11-22
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• 2007

This paper is to discuss analytical techniques to estimate demand sizes and volumes that determine optimal locations for multiple facilities for a given services. While demand size estimation is a core part of location modeling to enhance solution quality and practical applicability, the estimation method has been used in limited and restrict parts such as a single population centroid in a given larger census boundary area or small theoretical application experiments(e.s. census track and enumeration district). Therefore, this paper strives to develop an analytical estimation method of demand size that converts area based demand data to point based population weighted centroids. This method is free to spatial boundary units and more robust to estimate accurate demand volumes regardless of geographic boundaries. To improve the estimation accuracy, this paper uses house weighted value to the population centroid calculation process. Then the population weighted centroids are converted to individual demand points on a grid formated surface area. In turn, the population weighted centroids, demand points and network distance measures are operated into location-allocation models to examine their roles to enhance solution quality and applicability of GIS location models. Finally, this paper demonstrates the robustness of the weighted estimation method with the application of location-allocation models.

• Korean Journal of Social Welfare
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• v.61 no.1
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• pp.5-32
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• 2009

The purpose of this study is to examine the effects of organizational culture types (rational culture, developmental culture, group culture, and hierarchical culture) on Community-Centered Social Inclusion Orientation(COSI) among social service organizations for people with disabilities. More specifically, this study developed and empirically tested two theoretical models where each of organizational culture types were hypothesized to affect COSI either directly or indirectly through market orientation. For data collection, self-administered type questionnaires were mailed to 416 social service organizations for people with disabilities across the nation and 293 responded (response rate: 70.4%) from June 1 to September 22, 2006. For analysis, however, only 263 respondents were used, excluding Independent living centers due to their small size and short history. Structural Equation Modeling was employed for analysis and Full Information Maximum Likelihood was used for estimation. Findings indicated that market orientation had a significant effect on COSI. In addition, developmental culture and hierarchical culture were found to affect COSI directly while rational culture and group culture were found to affect COSI indirectly through market orientation. These findings imply that market orientation needs to be emphasized as a strategy in order to enhance social inclusion orientation for those organizations. Given that all the four types of organizational culture have direct or indirect impacts on COSI, those organizations are also advised to develop the four types of organizational culture harmoniously rather than one single type of organizational culture.

• Science of Emotion and Sensibility
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• v.12 no.2
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• pp.181-192
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• 2009

The purpose of this study was to explain the attitudes and acceptance toward the smart clothing adopted by the TAM(Technology Acceptance Model). A theoretical model on consumer acceptance of the commercialized smart clothing was constructed on the basis of previous studies and a review of literature and tested the path analysis. For the data analysis, statistical methods of confirmatory factor analysis, correlation, and covariance structural analysis using AMOS 5.0 package were employed. The results from a web-based survey of 557 online consumers indicate that the TAM by Davis(1989) adopted by perceived value according to market price was able to explain consumer acceptance of smart clothing substantially well. Using structural equation modeling, eight of the six hypotheses investigated in this study were supported. The results of the testing of the hypothesis were as fellows: First, perceived ease of use had a side effect on attitude through perceived usefulness. In addition, the attitude was found to affect consumer acceptance. Second, perceived usefulness was found to affect consumer attitude on perceived value, however, had not significant effect on consumer acceptance toward smart clothing. Third, perceived value was found to affect both consumer acceptance and attitude toward smart clothing. Finally, the attitude toward smart clothing had a direct effect on the consumer acceptance.