• Journal of Korean Society for Atmospheric Environment
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• v.29 no.4
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• pp.378-389
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• 2013

In Korea, studies on the indoor air quality have been conducted since mid of 1980s. The turning point occurred in 2003 by establishing the act of the indoor air quality management for public facilities. According to the law, the basic plan for indoor air quality management is prepared by government every five years, affecting greatly governmental policy and related academia and industries. Indoor air quality survey was mostly carried out among indoor air quality researches. After then, assessment of health effect and air cleaning technology were studied. Although various control technologies for particle, bioaerosol, odor, and hazardous chemicals have been applied to indoor environments, breakthrough technologies are needed to solve real problems facing at the applied environments. In the future, issue of indoor air quality is more interested and both management policy and control technology are key factors in order to realize comfort and healthy indoor environments.

• Journal of Korean Society on Water Environment
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• v.31 no.2
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• pp.209-215
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• 2015

The purpose of this study is to evaluate the characteristic of the iron oxide carrier for removing arsenic contained in the groundwater. 4 types of iron oxide carrier used in the study is iron oxide coated sand carrier (IOCSC), iron oxide coated zeolite carrier (IOCZC), iron oxide plasticity carrier (IOPC) and platinum iron oxide plasticity carrier (PIOPC). The results of this study, IOPC is showed high arsenic adsorption strength and the maximum amount of adsorption than the IOCC. Based on the results of the arsenic adsorption characteristic, by using IOCC was conducted to column test. As a result, PIOPC is showed a high arsenic adsorption amount than IOPC, it was found that the time required to reach the breakthrough point is also extended. Therefore it is determined that stably compliance with water quality standards enhanced drinking water when using the PIOPC.

• Biotechnology and Bioprocess Engineering:BBE
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• v.6 no.6
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• pp.376-385
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• 2001

Considerable attention has been focused in recent years upon the field of biosorption for the removal of metal ions from aqeous effluents. Compared to other technologies, the advan-tages of biosortption are the high purity of the treated waste water and the cheap raw material. Really, the first major challenge for the biosorption field is to select the most promising types of biomass. Abundant biomass types either generated as a waste by-product of large-scale industrial fermentations particularly fungi or certain metal-binding seaweeds have gained importance in re-cent years due to their natural occurrence, low cost and, of course good performance in metal biosorption. Industrial solutions commonly contain multimetal systems or several organic and in organic substances that form complexes with metals at relatively high stability forming a very complex environment. When several components are present, interference and competition phe-nomena for sorption sites occur and lead to a more complex mathematical formulation of the process. The most optimal configuration for continuous flow-biosorption seems to the packed-bed column which gets gradually from the feed to the solution exit end. Owing to the com-petitive ion exchange taking place in the column, one or more of the metals present even at trace levels may overshot the acceptable limit in the column effluent before the breakthrough point of the trargeted metal. Occurrence of 'overshoot's and impact on havey metal removal has not been analyzed enough. New trends in biosorption are discussed in this review.

• Journal of Information Technology Services
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• v.18 no.2
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• pp.75-96
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• 2019

These days, many companies use information systems as a basis for organizational management activities and as an important component of sustainable management. Thus, securing and operating a high-quality information system that can improve the efficiency of business processes is a large part of corporate competitiveness. In order to get such a critical information system, it is only possible to successfully carry out the project. Various attempts and studies have been undertaken to increase the success rate of the project. However, the reality is that the success rate is still not getting much better. In this study, the concept of quality of service, which has long been actively studied in marketing area, was applied as a new factor to enhance the project's success. In this study, project performance activities were defined as the act of providing services. A survey of 164 valid collection data was analyzed. The analysis used SPSS 23. Four process quality factors (customer participation, customer response, knowledge and skills, reliability) and 21 metrics were derived. Through this research, I hope to be the starting point of applying process quality concept as a new breakthrough to increase success rate of project.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.6
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• pp.2441-2445
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• 2015

Background: Several risk factors leading to malignant transformation of hydatidiform moles have been described previously. Many studies showed that prophylactic chemotherapy for high risk hydatidiform moles could significantly decrease the incidence of malignancy. Thus, it is essential to discover a breakthrough to determine patients with high risk malignancy so that prophylactic chemotherapy can be started as soon as possible. Objectives: Development of a scoring system of risk factors as a predictor of hydatidiform mole malignant transformation. Materials and Methods: This research is a case control study with hydatidiform mole and choriocarcinoma patients as subjects. Multiple logistic regression was used to analyze the data. Odds ratios (OR), attributable at risk (AR : OR-1) and risk index ($ARx{\beta}$) were calculated for develoipment of a scoring system of malignancy risk. The optimal cut-off point was determined using receiver operating characteristic (ROC) curve. Results: This study analyzed 34 choriocarcinoma cases and 68 benign hydatidiform mole cases. Four factors significantly increased the risk of malignancy, namely age ${\geq}35$ years old (OR:4.41, 95%CI:1.07-16.09, risk index 5); gestational age ${\geq}$ 12weeks (OR:11.7, 95%CI:1.8-72.4, risk index 26); uterine size greater than the gestational age (OR:10.2, 95%CI:2.8-36.6, risk index 21); and histopathological grade II-III (OR:3.4, 95%CI:1.1-10.6, risk index 3). The lowest and the highest scores for the risk factors were zero and 55, respectively. The best cut-off point to decide high risk malignancy patients was ${\geq}31$. Conclusions: Malignant transformation of hydatidiform moles can be predicted using the risk scoring by analyzing the above four parameters. Score ${\geq}31$ implies high risk patients so that prophylactic chemotherapy can be promptly administered for prevention.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.11
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• pp.1025-1032
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• 2009

This study investigated a possibility to develop an adsorption process for volatile organic compounds (VOCs) of the solvent emitted during dry cleaning. Pitch activated carbon fiber (ACF) was chosen as an adsorbent of VOCs, and an electric swing adsorption process was utilized for the reproduction of the adsorbent after the completion of VOCs adsorption. Effects of ACF types and several solvents such as trichloroethylene (TCE) and toluene were examined on breakthrough curves and amounts of adsorbed VOCs. ACF was pretreated under various conditions in order to enhance the amounts of the adsorbed VOCs. Temperatures and voltages were measured for the reproduction of the ACF after full adsorption. ACF having micropores exhibited high adsorption of TCE, and high surface area of ACF could increase the adsorption property of toluene. In general, ACF could adsorb 41~54% TCE of the adsorbent weight. The increase of inlet VOCs concentration significantly decreased the breakthrough time and slightly lowered the amounts of adsorbed VOCs. Thus, ACF could effectively adsorb VOCs in low concentration in the feed stream. ACF pretreated by heat under vacuum showed excellent toluene adsorption with controlling oxygen functional groups on the ACF surface, which revealed that vacant carbon site could be the adsorption point of toluene. Most adsorbed toluene was desorbed at $150^{\circ}C$.

• Journal of Korean Society of Environmental Engineers
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• v.33 no.10
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• pp.717-722
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• 2011

Currently, melamine is being used variously in our lives such as resins, flame retardants, adhesive, laminate etc. And understandably sewer of stream of wastewater containing Melamine has also increased. GHS (Globally Harmonized System of Classification and Labelling of Chemicals) of EU safety guidelines says that it can cause cancer. Still, study on toxicity of Melamine is going on. In this research, melamine contamination level of the Han River and River Basin was analyzed by HPLC/UV. And the experiments of GAC adsorption were conducted and the model was studied. We collected the 3 same samples at the suburbs of Paldang Dam located in the relative upstream in Han River and Ttukseom amusement park, the downstream region and collected samples equally at the Hongreung stream, Wangsuk stream, Cheonggye stream among streams flowing into Han River and then measured Melamine concentration after purification. As a result, melamine was not detected at the suburbs of Paldang Dam and it was detected at Ttukseom amusement park, the downstream of it, in the concentration of $0.312{\mu}g/L$. The Wangsuk stream with $0.578{\mu}g/L$ highest Cheonggye stream and Hongreung stream was detected with each $0.197{\mu}g/L$ and $0.325{\mu}g/L$. Although the concentration was low in general, melamine detection could be checked at most point. In 1970, the world capacity of Melamine was estimated at 200,000 ton, with current production estimated to be 1,400,000 ton. Melamine of Han River and rivers flowing into Han River is present at low concentration but pollution will increase in the future due to increase of use. Depending on the size of activated carbon in the experiment were slightly different. But the breakthrough model is almost identical.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.3 no.2
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• pp.87-95
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• 1983

Trihalomethane removal efficiency by a fixed bed carbon adsorber was a subject of this study. Along with laboratory scale column operations, a simple adsorption model was developed to predict removal efficiency. The adsorption model includes an overall mass transfer coefficient, K and Freundlich adsorption constants, $K_F$ and n. Simulation results showed that increasing K and $K_F$ or decreasing n would take more loading and prolong run time of the adsorption bed. Typical S-shaped breakthrough curves were obtained from the experiments. The operational results at $20^{\circ}C$ and $25^{\circ}C$ indicated that a moderate difference in water temperature would not affect the treatment efficiency significantly. The adsorption constants determined from the column operation and the model simulation were reasonably close to those obtained from the isotherm test. It may be concluded that trihalomethane can be removed successfully by a fixed bed carbon adsorber.

• Journal of Technology Innovation
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• v.23 no.4
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• pp.245-287
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• 2015

Architectural innovation is being regarded as one having major influence on the rate of performance improvement, even if this type of innovation does not show the highest level of technological discontinuity. Radical innovation firms who made a breakthrough product new to an industry, approach a certain point of time in which the speed of performance improvement very slows down, if architectural efficiency is not improved. At this time, this firm's prior experience in developing inferior, but very creative radical product architecture might work as paradoxical impediments to architectural innovation, the following important event. This study intends to understand the relationship between shifts in market needs and technological problem solving strategy, which exist before. after, and during architectural innovation, based on conceptual framework in which both stage and problem solving perspectives are combined. Korean SME, JAHWA Electronics could succeed in diffusion of vibration motor, by overcoming technological mental model locked in seemingly successful first generation architecture of coin type vibration motor. In-depth single case study including interviews and active participative observations was carried out for building longitudinal understanding of this innovation concept.

• Clean Technology
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• v.9 no.4
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• pp.179-187
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• 2003

The technology of fluidized bed to use dry sorbent can be new technology that reduce the operating cost and make efficient operation. Therefore, this study investigated $CO_2$ control by dry sorbents with operating variables in a fluidized bed, compared with fixed bed for $CO_2$ adsorption capacity and pressure drop, and presented the $CO_2$ adsorption capacity of activated carbon, molecular sieve 5A, molecular sieve 13X, and activated alumina. As the results of this study, the basic data could be achieved for operation of fluidized bed process, and fluidized bed process presented relatively high $CO_2$ adsorption capacity and low pressure drop with the increase of gas velocity. In addition, molecular sieve 5A showed 1.1~3.0-fold later breakthrough point and 1.1~2.7-fold higher adsorption capacity than the other dry sorbents.