• Journal of Korean Society for Quality Management
• /
• v.40 no.4
• /
• pp.589-598
• /
• 2012

Purpose: Determination of the importance values of quality attributes is very important to integrate the Kano model with QFD. A new method to determine the importance values of quality attributes is proposed. Methods: ASC(Average Satisfaction Coefficient) is proposed in order to determine the importance values of quality attributes. To evaluate the effectiveness of ASC, a case study of modern TV sets is conducted, and the performance of ASC is compared with direct importance evaluation and AHP pairwise comparisons. Results: The result of ASC application is similar with those of direct importance evaluation and AHP pairwise comparison. Conclusion: ASC is an effective instrument to determine the importance values of quality attributes. It doesn't need a cumbersome process like AHP pairwise comparison, and can be calculated using the data for the conventional Kano model.

• Journal of Korean Society for Quality Management
• /
• v.30 no.4
• /
• pp.15-25
• /
• 2002

This paper considers supplier selection process for e-business & ISO 9001 quality management system environments. Determining suitable suppliers in the electronic commerce has become a key strategic consideration. However, the nature of these decisions is usually complex and unstructured. In this paper, a Quality Estimated Supplier Selection (QESS) model is proposed to deal with the supplier selection problems in the e-business(Business to Business: B to B). In the supplier selection, quality management factors will be considered for the first time, and then price, and delivery etc. In the first level, we deal with the quality management factors such as quality management audit, product test, engineering man-power, capability index and training time etc., based on the five point scale. In the second level, a QESS model determines the final solution by considering factors such as price, production lead-time and delivery time.

• Journal of Korean Society on Water Environment
• /
• v.37 no.5
• /
• pp.335-343
• /
• 2021

Water quality prediction is essential for the proper management of water supply systems. Increased suspended sediment concentration (SSC) has various effects on water supply systems such as increased treatment cost and consequently, there have been various efforts to develop a model for predicting SSC. However, SSC is affected by both the natural and anthropogenic environment, making it challenging to predict SSC. Recently, advanced machine learning models have increasingly been used for water quality prediction. This study developed an ensemble machine learning model to predict SSC using the XGBoost (XGB) algorithm. The observed discharge (Q) and SSC in two fields monitoring stations were used to develop the model. The input variables were clustered in two groups with low and high ranges of Q using the k-means clustering algorithm. Then each group of data was separately used to optimize XGB (Model 1). The model performance was compared with that of the XGB model using the entire data (Model 2). The models were evaluated by mean squared error-ob servation standard deviation ratio (RSR) and root mean squared error. The RSR were 0.51 and 0.57 in the two monitoring stations for Model 2, respectively, while the model performance improved to RSR 0.46 and 0.55, respectively, for Model 1.

• Journal of Environmental Health Sciences
• /
• v.41 no.2
• /
• pp.90-101
• /
• 2015

Objective: This study was conducted to develop a chemical oxygen demand (COD) regression model using water quality monitoring data (January, 2014) obtained from the Han River auto-monitoring stations. Methods: Surface water quality data at 198 sampling stations along the six major areas were assembled and analyzed to determine the spatial distribution and clustering of monitoring stations based on 18 WQPs and regression modeling using selected parameters. Statistical techniques, including combined genetic algorithm-multiple linear regression (GA-MLR), cluster analysis (CA) and principal component analysis (PCA) were used to build a COD model using water quality data. Results: A best GA-MLR model facilitated computing the WQPs for a 5-descriptor COD model with satisfactory statistical results ($r^2=92.64$,$Q{^2}_{LOO}=91.45$,$Q{^2}_{Ext}=88.17$). This approach includes variable selection of the WQPs in order to find the most important factors affecting water quality. Additionally, ordination techniques like PCA and CA were used to classify monitoring stations. The biplot based on the first two principal components (PCs) of the PCA model identified three distinct groups of stations, but also differs with respect to the correlation with WQPs, which enables better interpretation of the water quality characteristics at particular stations as of January 2014. Conclusion: This data analysis procedure appears to provide an efficient means of modelling water quality by interpreting and defining its most essential variables, such as TOC and BOD. The water parameters selected in a COD model as most important in contributing to environmental health and water pollution can be utilized for the application of water quality management strategies. At present, the river is under threat of anthropogenic disturbances during festival periods, especially at upstream areas.

• Management & Information Systems Review
• /
• v.9
• /
• pp.65-80
• /
• 2002

As the growth of Internet business, many web sites have been developed their own Internet business strategies. Yet, many web sites have difficulties to make profit. In this paper, an economic model is developed to analyze web sites' quality and pricing strategies when they initiate their services as free services and develop advertising services and other charged services. By analyzing the economic model, optimal quality and prices was found. And by analyzing the optimal strategy, I found that web sites should properly decide their market share on initial customer. Finally, the importance of web sites' productivity to make profit is emphasized.

• Journal of the Korean Operations Research and Management Science Society
• /
• v.10 no.2
• /
• pp.1-14
• /
• 1985

This problem of product selection and princing are considered in congested and uncongested markets. In a congested market, such as a computer service market, product quality (the level of congestion) is partly a function of the amount of usage, which in turn depands on user choice. In an uncongested market, product qualities are set solely by providers. A model of quality and capacity variation is developed using a state equation description to represent user optimizing behavior. The model is used to study the problem of scarce resources among competing user demands through quality-dependent pricing.

• Journal of Environmental Science International
• /
• v.5 no.3
• /
• pp.377-385
• /
• 1996

This study aims at the estimation of a river management flow in urban basin analyzing Sinchun basin to be the tributary of Kumho river basin. The river management flow has to satisfy a low flow as natural flow and an environmental preservation flow estimated by a dilution flow to satisfy a target water quality in drought flow. Therefore for the estimation of a river management flow in Sinchun in this study, first Tank model as a basin runoff model estimates a low flow, a drought flow from a flow duration curve in Sinchun, second QUAL2E model as water quality model simulates water quality in Sinchun and estimates environmental preservation flow to satisfy a target water qua%its, BOD 8 mg/l by a dilution flow derived from Kumho river, Nakdong river and around water. And the river management flow is estimated by addition of a use flow and a loss flow to more flow between a low-flow and an environmental preservation flow.

• Proceedings of the Korean Society of Agricultural Engineers Conference
• /
• 2003.10a
• /
• pp.515-518
• /
• 2003

Mathematical models can be used to evaluate the effects of operational alternatives of dam on the downstream aquatic environment. An unsteady, one-dimensional water quality model, CE-QUAL-RIVI was calibrated and validated in Geum river as a sub model for the realtime water management system in the basin. The main usage of the model within the system is to predict the effects of flow regulation by Daecheong Dam on the downstream water quality. The validated model was then used to simulate dynamic water quality changes at several key stations responding to different scenarios of reservoir releases under a hypothetical spill condition. The model showed fairly good performance in the simulation of hydrodynamic and mass transport processes under highly unsteady conditions.

• Journal of Korean Society for Quality Management
• /
• v.36 no.4
• /
• pp.65-76
• /
• 2008

The purpose of this study is to contribute to escalation of a management quality of local public enterprise through integrating local public enterprise evaluation(LPEE) and Malcolm Baldrige Model(MBM). In order to achieve the purpose, I suggested that develop an integration model of LPEE and MBM criteria and use AHP(Analytic Hierarchy Process) as a technique posting weight value to criteria. Of two suggests, it is the former to date or discuss seriously. Therefore the integration model is redesigned for leadership/strategy category(leadership, strategy), management system category(customer management system, business management system, measurement/knowledge management system), and management result category(business result, customer satisfaction result, human resource management result, financial management result).

• Journal of Environmental Impact Assessment
• /
• v.23 no.3
• /
• pp.177-186
• /
• 2014

Depending on the change of lifestyle and the improvement of people's living standards and rapid industrialization, urbanization of recent, demand for water is increasing rapidly. So emissions of domestic wastewater and various industrial waste water has increased, and water quality is worsening day by day. Therefore, in order to provide a measure against the occurrence of water pollution accident, this study was tried to simulate water pollution accident. This study simulated 2008 Gimcheon phenol accident using 1,2-D model, and analyze scenario for prevent of water pollution accident. Consequently the developed 1-D model presents high reappearance when compared with 2-D model, and has been able to obtain results in a short simulation run time. This study will contribute to the water pollution incident response prediction system and water quality analysis in the future.