• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.29 no.3
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• pp.358-367
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• 2019

Objectives: This study aimed to review model algorithms and input parameters applied to some exposure models and to compare the simulated estimates using an exposure scenario from each model. Methods: A total of five exposure models which can estimate inhalation exposure were selected; the Korea Ministry of Environment(KMOE) exposure model, European Centre for Ecotoxicology and Toxicology of Chemicals Targeted Risk Assessment(ECETOC TRA), SprayExpo, and ConsExpo model. Algorithms and input parameters for exposure estimation were reviewed and the exposure scenario was used for comparing the modeled estimates. Results: Algorithms in each model commonly consist of the function combining physicochemical properties, use characteristics, user exposure factors, and environmental factors. The outputs including air concentration ($mg/m^3$) and inhaled dose(mg/kg/day) are estimated applying input parameters with the common factors to the algorithm. In particular, the input parameters needed to estimate are complicated among the models and models need more individual input parameters in addition to common factors. In case of CEM, it can be obtained more detailed exposure estimates separating user's breathing zone(near-field) and those at influencing zone(far-field) by two-box model. The modeled exposure estimates using the exposure scenario were similar between the models; they were ranged from 0.82 to $1.38mg/m^3$ for concentration and from 0.015 to 0.180 mg/kg/day for inhaled dose, respectively. Conclusions: Modeling technique can be used for a useful tool in the process of exposure assessment if the exposure data are scarce, but it is necessary to consider proper input parameters and exposure scenario which can affect the real exposure conditions.

• Journal of the Korean Institute of Gas
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• v.22 no.2
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• pp.34-45
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• 2018

The cleat system in coalbed methane (CBM) reservoirs is generally occupied by water which liberated during the coalification process, and behavior of water have influence on CBM production performance. Therefore, it is essential to investigate the effect of the water saturation to operate the degasification process and predict the CBM production performance properly. In this study, type curve analyses were performed on CBM reservoirs under various water saturation to improve the prediction of production performance. A CBM reservoir models with fully-, modestly-, and undersaturated reservoir were built to get production data using GEM by CMG Ltd., and the data were matched with Fetkovich, Palacio-Blasingame(P-B), and Agarwal-Gardner (A-G) type curve. The results showed that undersaturated reservoir was successfully matched by A-G type curve, while the Fetkovich type curve was inappropriate for matching in the late time. The modestly saturated model could be almost corresponded with all the type curve methods at late production period. For the fully saturated model, after peak production had been reached, both P-B and A-G methods showed a proper match to the reservoir production data without long-term production period. Based on the results, merit and demerit of each type curve under specific water saturation were analyzed and listed. Therefore, it is believed that the production data analysis with proper type curve model considering water saturation can be performed to predict accurate production performance.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.1
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• pp.97-104
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• 2010

At present, the biological nutrient removal (BNR) process for removal of nitrogen and phosphorus is being constructing to keep pace with the reinforced standard of effluent quality and the traditional activated sludge process of preexistence is being promoting to retrofit. At the most case of retrofitting, processes are subjected to be under consideration as alternative BNR process for retrofitting. However, process evaluation methods are restricted to compare only treatment efficiency. Therefore, when BNR process apply, process evaluation was needed various method for treatment efficiency as well as sludge production and aeration cost, and all. In this study, the evaluation method of alternative process was suggested for the case for retrofitting S wastewater treatment plant which has been operated the standard activated sludge process. Three BNR processes for evaluation of proper alternatative process were selected and evaluated with suggested method. The selected $A^2$/O, VIP and DNR processes were evaluated using the mathematical model which is time and cost effective as well as gathered objective evaluation criteria. The evaluation between 5 individual criteria was possible including sludge production and energy efficiency as well as treatment performance. The objective final decision method for selection of optimal process was established through the fuzzy inference.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.7
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• pp.81-88
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• 2020

The geometry and the defect of the groove of the part provoke a sudden change of stress in a local region. The objective of this paper is to investigate the effects of the geometry and the imperfection of a small groove on stress distributions in the vicinity of the joined region for the ABS part with a thin wall using a three-dimensional finite element analysis (FEA). Several types of groove are designed to improve joining characteristics in the vicinity joined region. The imperfection model of the small-sized groove is obtained from observation of deposition characteristics of a fused deposition modeling process. Local stress distributions in the vicinity of the joined region are predicted by the FE model with refined meshes. The influence of the angle and the imperfection of the groove on appearance regions of the maximum stress and distributions of the defined principal stress for different loading conditions is examined using the results of FEAs. Finally, a proper design of the groove is proposed to improve joining characteristics between the substrate and the ABS part.

• International Commerce and Information Review
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• v.6 no.2
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• pp.107-127
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• 2004

The rapid development of internet information technology has increased interest in e-Trade these days, but it is not activated greatly up to now. In order to promote e-Trade, it is essential to construct cooperative process such as connecting systems among trade related parties. Building e-Trade platform which is based on the infrastructure of the past trade automatic system is key point of promoting e-Trade. To do this, a study on the basic concept and specific components of e-Trade platform is needed absolutely. At this point of view, after this paper has examined domestic and foreign studies on the fundamental technologies about electronic commerce, it drew several key technologies that could be applied to e-Trade considering the current IT trend. Then it evaluates these technologies according to Technology Reference Model(TRM) of the National Computerization Agency. This will help us to show the operation strategy as well as the concept of future e-Trade platform and its composition. On the basis of the theoretical background, this paper classified NCA's technology model into 6 fields, which are application. data, platform, communication, security and management. Considering the key technologies, e-Trade platform has to be mutually connected and accept international standards such as XML. In the aspect of business side, trade relative agencies' business process as well as trading company's process has to be considered. Therefore, e-Trade platform can be classified into 3 parts which are service, infrastructure and connection. Infrastructure part is compared of circulating and managing system of electronic document, interface and service framework. Connecting service (application service) and additional service (application service) consist of service part. Connecting part is a linking mutual parts and can be divided into B2B service and B20 service. The organization operating this e-trade platform must have few responsibilities and requirements. It needs to positively accept existing infrastructure of trade automatic system and improving the system to complete e-trade platform. It also have to continuously develop new services and possess ability to operate the system for providing proper services to demanders. As a result, private sector that can play a role as TTP(Third Trust Party) is adequate for operating the system. In this case, revising law is necessary to support the responsibility and requirement of private sector.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.38 no.6
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• pp.458-469
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• 1989

A measurement method is proposed which finds 3-D position and attitude of a known polyhedra utilizing shading information. Through the systematic interpretation of relations between polyhedra and its image as well as shadow image and also the determination of candidate position, 3-D information with respect to vertex of polyhedra is extracted. Following preprocessing of this information, the image of polyhedra is represented in terms of the scene with positioned object and the correspondence is searched by means of matching process between a scene description of the object and the correspondence is searched by means of matching process between a scene description of the object and a model description stored in data-base. In the experiments, initially 3-D information is employed to select several model regions, and objects are recognized through matching process with respect to scene regions. The results demonstrate that the recognition system performs with a high efficiency by proper selection of the threshold values.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.6
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• pp.749-756
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• 2021

Thanks to PLC and IoT Sensor, huge amounts of data has been accumulated onto the companies' databases. Machine Learning Algorithms for the predictive model with good performance have been widely utilized in the manufacturing process. We present how to improve the performance of machine learning predictive models. To improve the performance of the predictive model, typical techniques such as increasing the sample size, optimizing the hyper parameters for the algorithm, and selecting a proper machine learning algorithm for the predictive model would be shown. We suggest some new ways to make the model performance much better. With the proposed methods, we can build a better predictive model for predicting and controlling product qualities and save incredibly large amount of quality failure cost.

• Journal of Korean Library and Information Science Society
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• v.45 no.1
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• pp.125-147
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• 2014

The aim of this study is to develop and suggest a reading strategy to learn for integrating reading and writing. The reading and writing strategy could be divided in directed strategies related to the cognitive process and indirected strategies to carry out the process successfully. Therefore, its strategies are constructed of the indirected strategy corresponding with the instructional design model and the direct strategy containing specific action plans of the model's progressive stages. When considering the reading to learn could be run as a program in the school, in this study, the basic model of the indirected strategy is devised with four steps of 'preparing-designing-implementing-evaluating'. And the implementing stage of the read to learn combining reading and writing is consisted of six steps as 'selecting subjects-considering contents-searching-writing-correcting-publishing'. Also, proper indirected strategies such as graphic organization and checklists are suggested in order to assist reading and writing activities in the implementing stage.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2004.11a
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• pp.256-260
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• 2004

As a large portion of defence budget are alloted for military facility construction, reasonable budget estimation in the planning stage has been officers' main concerns. However the proper estimation of construction cost is difficult to be carried out due to the absence of systematic criteria. To improve the budget estimation for military facility construction, this study proposes a cost index model which can convert historical cost to current cost. Thus the developed cost index would enhance effectiveness of budget estimation process 3nd support reasonable decision making. This cost index model is developed by analyzing historical cost data with statistical methodology The study is executed by following process. First, factors which affect construction cost for the most are selected by analyzing historical cost data. second, the selected factors are categorized material cost, labor cost and equipment cost, and weights of those factors are calculated by dividing the cost of each factor by total item costs. Last, cost index is developed by using weighted average method.

• Journal of Korean Society of Environmental Engineers
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• v.34 no.5
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• pp.312-315
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• 2012

In this study, the model which can predict the quality of effluent has been implemented through multiple regression analysis to use operation data of a sewage treatment plant, to which a media process is applied. Multiple regression analysis were carried out by cases according to variable selection method, removal of outliers and log transformation of variables, with using data of one year of 2011. By reviewing the results of predictable models, the accuracy of prediction for $COD_{Mn}$ of treated water of secondary clarifiers was over 0.87 and for T-N was over 0.81. Using this model, it is expected to set the range of operating conditions that do not exceed the standards of effluent quality. In conclusion, the proper guidance on the effluent quality and energy costs within the operating range is expected to be provided to operators.