• Membrane and Water Treatment
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• v.10 no.4
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• pp.299-305
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• 2019

Managed aquifer recharge (MAR) systems are gaining interest as an alternative to conventional water resources. However, when the water recovered in MAR systems, dissolved iron and manganese species may easily oxidize and they cause well screen clogging or require abandonment of extraction wells. In this study, both oxic and anoxic conditions were analyzed to verify the feasibility of the membrane filtration performance under various solution chemistries. The fouling mechanisms of the metal ions under anoxic conditions were also investigated by employing synthetic wastewater. The fouled membranes were then further analyzed to verify the major causes of inorganic fouling through SEM and XPS. The newly suggested anoxic process refining existing membrane process is expected to provide more precious information about nanofiltration (NF) membrane fouling, especially for demonstrating the potential advantages to chemical-free drinking water production for indirect potable reuse.

• IEMEK Journal of Embedded Systems and Applications
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• v.18 no.1
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• pp.9-17
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• 2023

This paper relates to the development of a device for measuring the efficiency of a solar panel based on a variable constant current, and proposed a standard for reuse of the solar panel. By applying a variable constant current circuit to a solar panel efficiency measuring device, it was easy to apply a maximum power point tracking (MPPT) algorithm. In addition, a load dispersion method was applied to measure the efficiency of a high-capacity solar panel. and it is possible to solve a problematic thermal runaway during a MOSFET parallel operation by applying the load dispersion method. As a result of the experiment, the solar panel efficiency measuring device was able to accommodate a large solar panel of 350W, which is the maximum measurement goal. In this paper, the validity was confirmed through the 310W solar panel efficiency measurement experiment collected after removal.

• International conference on construction engineering and project management
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• 2009.05a
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• pp.949-955
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• 2009

Managing knowledge effectively is a critical factor for the competitive power of a company. There are efforts to use knowledge as an important resource in many industrial areas and likewise the interest in knowledge management is growing in the construction industry. Nevertheless, there are limitations in the current capture and reuse of knowledge in the construction industry owing to the unique characteristics of the knowledge created during the processes of projects. The knowledge produced during the processes of construction projects is project-oriented, experiential and context specific and due to these characteristics the reuse of knowledge is difficult. In this research, we focus on capturing and identifying the characteristics of construction knowledge and propose a method to apply these characteristics in developing an ontology based construction knowledge retrieval system to improve construction knowledge retrieval and enhance knowledge reuse.

• Journal of the Semiconductor & Display Technology
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• v.22 no.3
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• pp.142-148
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• 2023

In this paper, we identify performance issues in executing compute kernels from PolyBench, which includes compute kernels that are the core computational units of various data-intensive workloads, such as deep learning and data-intensive applications, on Processing-in-Memory (PIM) devices. Therefore, using our in-house simulator, we measured and compared the various performance metrics of workloads based on traditional out-of-order and in-order processors with Processing-in-Memory-based systems. As a result, the PIM-based system improves performance compared to other computing models due to the short-term data reuse characteristic of computational kernels from PolyBench. However, some kernels perform poorly in PIM-based systems without a multi-layer cache hierarchy due to some kernel's long-term data reuse characteristics. Hence, our evaluation and analysis results suggest that further research should consider dynamic and workload pattern adaptive approaches to overcome performance degradation from computational kernels with long-term data reuse characteristics and hidden data locality.

• Journal of Soil and Groundwater Environment
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• v.13 no.1
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• pp.32-42
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• 2008

A surfactant recovery and reuse process by selective adsorption with activated carbon was proposed to reduce surfactant cost in a soil washing process. Mathematical model simulation was performed for the whole process, which consists of soil washing, soil recovery, and soil re-washing. The optimal range of surfactant dosage was $6{\sim}10$-fold critical micelle concentration in soil. The efficiency of surfactant reuse process was decreased with increasing the dosage of activated carbon. Effectiveness factor for activated carbon significantly altered the efficiency of the reuse process unlike effectiveness factor for soil. Total requirement of surfactant was reduced to 20-30% with the reuse process compared to the conventional soil washing process. The contamination of wastewater after soil washing was reduced with the reuse process. This mathematical model can be used to estimate performance of the whole process of soil washing including surfactant recovery and to obtain optimal ranges of operating conditions without extra labor-intensive experimental works.

• Journal of Microbiology and Biotechnology
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• v.27 no.1
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• pp.141-148
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• 2017

The oxidation ditch (OD) is one of the most widely used processes for treating municipal wastewater. However, the microbial communities in the OD systems have not been well characterized, and little information about the shift of bacterial community during the startup process of the OD systems is available. In this study, we investigated the bacterial community changes during the startup period (over 100 days) of a full-scale OD. The results showed that the bacterial community dramatically changed during the startup period. Similar to the activated sludge samples in other studies, Proteobacteria (accounting for 26.3%-48.4%) was the most dominant bacterial phylum in the OD system, but its relative abundance declined nearly 40% during the startup process. It was also found that Planctomycetes proliferated greatly (from 4.79% to 13.5%) and finally replaced Bacteroidetes as the second abundant phylum in the OD system. Specifically, some bacteria affiliated with genus Flavobacterium exhibited remarkable decreasing trends, whereas bacterial species belonging to the OD1 candidate division and Saprospiraceae family were found to increase during the startup process. Despite of the bacterial community shift, the organic matter, nitrogen, and phosphorus in the effluent were always in low concentrations, suggesting the functional redundancy of the bacterial community. Moreover, by comparing with the bacterial community in other municipal wastewater treatment bioreactors, some potentially novel bacterial species were found to be present in the OD system. Collectively, this study improved our understandings of the bacterial community structure and microbial ecology during the startup of a full-scale wastewater treatment bioreactor.

• Journal of Korean Society of Environmental Engineers
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• v.39 no.7
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• pp.377-384
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• 2017

This study examined the possibility of solving the water shortage problem through the water reuse of buildings through the Suwon water reuse (greywater) facility installation project conducted as a pilot project of Ministry of Environment. Water reuse of individual building units can reduce city water demand by up to 25%. This is a level that can solve the water shortage problem in Korea. However, in order to revitalize the water reuse facilities of individual buildings, it is necessary to solve the problem of the user's rejection of the greywater and the economical problems. The resolution of the user's rejection can be solved by linking the MBR process with the AOP process. When the MBR process and the AOP process are operated in conjunction with each other, it is found that the users do not feel the water quality difference with the tap water. Economical problems can be solved at the water rate levels when the facility capacity is over 100 ton/day considering the construction cost and the operation cost, and when the operation cost alone is over 15 ton/day. Furthermore, when considering the social benefit cost, it is found that profit is generated from 150 ton/day.

• The KIPS Transactions:PartD
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• v.13D no.7 s.110
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• pp.1017-1026
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• 2006

Recently, distributed collaborative development environment has been recognized an alternative environment for product development in which multidisciplinary participants are naturally involving. Reuse of Product design information has long been recognized as one of core requirements for efficient product development. This paper addresses an image-based retrieval system to support product design information reuse. In the system, product images obtained from multi-modal devices are utilized to reuse design information. The proposed system conducts the segmentation of a product image by using a labeling method and generates an attributed relational graph (ARG) that represents properties of segmented regions and their relationships. The generated ARG is extended by integrating corresponding part/assembly information. In this manner, the reuse of assembly design information using a product image has been realized. The main advantages of the presented system are following. First, the system is not dependent to specific design tools, because it utilizes multimedia images that can be obtained easily from peripheral devices. Second ratio-based features extracted from images enable image retrievals that contain various sizes of parts. Third, the system has shown outstanding search performance, because we applied various information of segmented part regions and their relationships between parts.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.9
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• pp.518-525
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• 2018

In the 21st century, human beings are becoming increasingly concerned about greenhouse gas emissions as the environment changes due to climate change become serious. The temperature of Korea has risen by approximately $1.5^{\circ}C$ from 1904 to 2000, and the climate is changing gradually to a subtropical climate. As a result, the frequency of floods and droughts increases, so that the water available to humans is decreasing every year, and the cost of using city water is rising every year. The reuse of wastewater that is normally abandoned is inevitable. This study examined the monthly data for 6 months of operation by installing a reuse system of concentrated wastewater (Re R/O System) that is generated during the process of manufacturing de-ionized water (DI-Water System) used in semiconductor processing. As a result of the survey, the city water supply saved approximately $2,767m^3$ per month. The average annual greenhouse gas emissions was $1,329.07kg-CO_2$ per month due to the electricity consumption of the water reuse system. On the other hand, because of the reduction in city water supply, the average monthly average of $918.64kg-CO_2$ was reduced, and the greenhouse gas emissions were increased to $410.43kg-CO_2$ per month. If it improves some processes in the water reuse system, the amount of greenhouse gas emissions can be reduced by an average of $254.41kg-CO_2$ per month.

• Journal of Service Research and Studies
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• v.9 no.2
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• pp.41-54
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• 2019

The increasing use of mobile applications is a phenomenon that has recently come to be beneficial to people in their private life due to increased income and changes in life style. In particular, analyzing customers' consumer sentiment can be seen as a pursuit form of convenience that enables efficient use of time and effort. In this study, based on previous studies, we examine the causal relation model that influences reuse intention, which is a dependent variable through perceived value as a parameter by measuring the service convenience for cafe mobile application. In order to accomplish purpose of this study, references related to service convenience, perceived value, and reuse intention were reviewed as literature research methods. For the empirical study, the research was carried out through Macro Mill Embrain Co., Ltd. Online research was conducted for one week from October 26 to November 8, 2018. There are 13 items of the collected data were excluded and 324 items suitable for irradiation were used. Study results show that service convenience of cafe mobile application has a positive effect on perceived value and reuse intention. In addition, in the relationship that cafe mobile app's service convenience has a significant (+) influence on reuse intention, perceived value proved to have meaningful results as intermediary roles. Implications of this study are as follows. First of all, this study will be helpful for cafe companies and consumers if utilize the service convenience of cafe mobile application in perceived value and reuse intention in marketing applications. Therefore, theoretically, we propose the development direction of cafe mobile application and present academic data for marketing strategy innovation and competitive advantage in the food service industry that conforms to the fourth industrial revolution era.