• Journal of Korean Society on Water Environment
• /
• v.25 no.1
• /
• pp.120-124
• /
• 2009

This study was performed to investigate the application of submerged membrane bioreactor (MBR) system for biological nutrient removal of municipal wastewater. MBR bioreactor consists of four reactors such as anaerobic, stabilization, anoxic and submerged membrane aerobic reactors with two internal recycles. The hydraulic retention time (HRT), sludge retention time (SRT) and flux were 6.2 hr, 34.1 days and $19.6L/m^2/hr$ (LMH), respectively. As a result of operation, the removal efficiency of $COD_{Cr}$, SS, TN and TP were 94.3%, 99.9%, 69.4%, and 74.6%, respectively. There was no significant effect of microbial activity after the maintenance cleaning using 200 mg/L of NaOCl. Membrane filtration for the treatment of municipal wastewater was performed for longer than 9 months without chemical recovery cleaning.

• Korean Journal of Veterinary Research
• /
• v.34 no.4
• /
• pp.867-872
• /
• 1994

Progesterone catabolizing enzyme, the enzyme $20{\alpha}$-hydroxysteroid dehydrgenase($20{\alpha}$-HSD) is pivotal in the regulation of ovarian function in rodents, which catabolizes progesterone into biologically inactive $20{\alpha}$-hydroxypregn-4-en-3-one($20{\alpha}$-OHP). In this study was carried out the influence of $20{\alpha}$-HSD activity of ovarian function, we investigated changes in ovarian cytosol $20{\alpha}$-HSD activity and serume progesterone concentration during the estrous cycles and pregnancy in rat. During the estrous cycles, the $20{\alpha}$-HSD activities were highest on the progestrous, but serum progesterone concentration was lowest on this phase. During the pregnancy, the $20{\alpha}$-HSD activities were relatively higher early pregnancy(day-1-3 gestation) and late pregnancy(day 21 to parturition), serum progesterone concentration was maintained significantly high to day 19 of gestation. The $20{\alpha}$-HSD activities were lower during the middle pregnancy. From these results, ovarian $20{\alpha}$-HSD activities may possibly act as physiologically very important in the control and maintenance of estrous cycles in rat.

• BMB Reports
• /
• v.51 no.2
• /
• pp.92-97
• /
• 2018

B cell leukemia/lymphoma 3 (Bcl3) plays a pivotal role in immune homeostasis, cellular proliferation, and cell survival, as a co-activator or co-repressor of transcription of the $NF-{\kappa}B$ family. Recently, it was reported that Bcl3 positively regulates pluripotency genes, including Oct4, in mouse embryonic stem cells (mESCs). However, the role of Bcl3 in the maintenance of pluripotency and self-renewal activity is not fully established. Here, we report the dynamic regulation of the proliferation, pluripotency, and self-renewal of mESCs by Bcl3 via an influence on Nanog transcriptional activity. Bcl3 expression is predominantly observed in immature mESCs, but significantly decreased during cell differentiation by LIF depletion and in mESC-derived EBs. Importantly, the knockdown of Bcl3 resulted in the loss of self-renewal ability and decreased cell proliferation. Similarly, the ectopic expression of Bcl3 also resulted in a significant reduction of proliferation, and the self-renewal of mESCs was demonstrated by alkaline phosphatase staining and clonogenic single cell-derived colony assay. We further examined that Bcl3-mediated regulation of Nanog transcriptional activity in mESCs, which indicated that Bcl3 acts as a transcriptional repressor of Nanog expression in mESCs. In conclusion, we demonstrated that a sufficient concentration of Bcl3 in mESCs plays a critical role in the maintenance of pluripotency and the self-renewal of mESCs via the regulation of Nanog transcriptional activity.

• KSBB Journal
• /
• v.21 no.3
• /
• pp.181-187
• /
• 2006

In this study, problems related with pH control in electrokinetic(EK) bioremediation of phenanthrene contaminated soil were observed, and the effects of pH control methods on the removal efficiency were investigated to search a further application strategy. In a preliminary experiment, it was found out by flask cultivation that a certain sulfate concentration was needed to degrade phenanthrene well using Sphingomonas sp. 3Y. However, when $MgSO_4$ was used as sulfate source in EK bioremediation, the bacterial activity reduced seriously due to the abrupt decrease of pHs in soil and bioreactor by the combination of magnesium and hydroxyl ions. When another strong buffering compound was used to control the pH problem, the good maintenance of the bacterial activity and pHs could be observed, but the removal efficiency decreased largely. When a low concentration of $MgSO_4$ was added, the removal efficiency decreased somewhat in spite of the good maintenance of neutral pHs. With the addition of NaOH as a neutralizing agent, the removal efficiency also decreased because of the increase of soil pH. Consequently the selection of electrolyte composition was a very important factor in EK bioremediation and some sulfate sources suitable for both bacterial activity and contaminant degradation should be investigated.

• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.15 no.5
• /
• pp.1-17
• /
• 2012

This study sought to discover new directions for management and operation national urban parks in Korea by analyzing the reality of the national government parks of Japan where these parks are already well established and managed. In the case of a Japanese national government park, its supporting system was established after the park was built. The means of management also shifted their direction from putting more priority to the administrative body to the residents. The management practices are changing process of its character with focus on residents as the main entity of activity from their existing position of participants. In other words, the national government parks of Japan are going beyond the previous practice of providing maintenance activities to providing experience, interpretation functions to these activities. Especially, they were establishing local networks to plan and execute programs in collaboration with the park management and NPOs. However, they fall short of tangible outcomes despite their continuous efforts to expand the community involvement and reduce the cost in maintenance. To facilitate the effective management of the urban parks in Korea in the near future, much thought needs to go into the management practices ensuring conservation of resources in the land of Korea, as well as people's use of recreation, community revitalization, and development and transfer of advanced technology to provide appropriate preparations to create urban parks in Korea.

• Journal of the Korea Society of Computer and Information
• /
• v.21 no.5
• /
• pp.119-126
• /
• 2016

Software maintenance becomes extremely difficult, especially caused by multiple versions in project-based or customer-oriented software development methodology. For reducing the maintenance cost, reengineering to software product line can be a solution to the software which either is a family of products nevertheless little different functionalities or are customized for each different customer's requirement. At an initial stage of the reengineering, the most important activity in software product line is feature extraction with respect to commonality and variability from the existing system due to verifying functional coverage. Several researchers have studied to extract features. They considered only a single version in a single product. However, this is an obstacle to classify the commonality and variability of features. Therefore, we propose a method for systematically extracting features from source code and its change history considering several versions of the existing system. It enables us to represent functionalities reflecting developer's intention, and to clarify the rationale of variation.

• Journal of the Korean Institute of Rural Architecture
• /
• v.20 no.2
• /
• pp.1-9
• /
• 2018

The purpose of this study was to develop guidelines for sustainability of back-to-farm community village in 4 aspects; social environment, maintenance and management, regional environment, and economic environment. These 4 aspects, which count for sustainability, based on the comprehensive comparative analysis about items that field survey and literature suggested. Conclusions of guideline are of the following. The guidelines on social environment are developed by 3 items; resident participation and activity, village leader, decision making in village and person in charge of operation. The guidelines on maintenance and management are developed by 5 items; village operation system, village regulation, transparency of management, village operation expenses, and management type. The guidelines on regional environment are developed by 2 items; support by central and local government, and area projects and connection to regional resources. The guideline on economic environment is not developed due to low demands of based production facilities and income increase facilities.

• Journal of Applied Reliability
• /
• v.16 no.3
• /
• pp.238-244
• /
• 2016

Purpose: Domestic electric railway Regenerative Energy Storage System seriously affects the maintenance cost of the total operating expenses of nearly 60% of the total LCC (Life Cycle Cost) due to high dependence on foreign Leading company. Therefore by developing the system, it is important to lower the maintenance cost in the domestic supply. This study about the capacitor Reliability test and the purpose of this study is development electric railway Regenerative Energy Storage System. Methods: In case of, having a close relation between the temperature and the reaction rate, Accelerated Model was known that according to Arrhenius' law of chemical activity. If you apply this formula in using allowable temperature range of the capacitor can induce the Arrhenius empirical formula used in much Manufacture Fields. We evaluate the capacitors Leading company through the Arrhenius model. in order to providing a base for the localization of Ultra Capacitor. Conclusion: In this paper, we conducted a reliability test. And it was performed by the accelerated life test and Cycle Test with temperature and C-rate. and then MTBF and B10 life are estimated by analyzing the accelerated life test result. This is thought to need detailed study applying complex stress than about whether it matches the actual behavior in electric railway.

• Journal of the Korean Home Economics Association
• /
• v.41 no.8
• /
• pp.213-227
• /
• 2003

The purpose of this study is to explore a weekly life of Korean high school students, especially focused on their activities, locations, and flow. The data were collected from 116 high school students by the Experiential Sampling Method, employing a cellular-phone as a signaling device. Students reported, in response to the 6964 random signals, that 43.4% of their time was spent for social/leisure activities. An additional 31% percent of time was used for productive activities and the rest of times belonged to maintenance activities. When engaged in productive activities, they usually reported anxiety, while they felt bored for social/leisure activities and flow for maintenance activities. The most pervasive context of their lives was school (42.8％), followed by home (33.3%), public space (24.6%), and educational institutes (9.2%). In general, they experienced flow for the most of the locations, except educational settings in which they felt anxiety. The flow for productive activities varied by gender, pending on where they had productive activities, while others did not show any significant differences in the activity flow by locations.

• Structural Monitoring and Maintenance
• /
• v.3 no.3
• /
• pp.233-257
• /
• 2016

This paper provides an overview on development of long-span bridges monitoring in Japan, with emphasis on monitoring strategies, types of monitoring system, and effective utilization of monitoring data. Because of severe environment condition such as high seismic activity and strong wind, bridge monitoring systems in Japan historically put more emphasis on structural evaluation against extreme events. Monitoring data were used to verify design assumptions, update specifications, and facilitate the efficacy of vibration control system. These were among the first objectives of instrumentation of long-span bridges in a framework of monitoring system in Japan. Later, monitoring systems were also utilized to evaluate structural performance under various environment and loading conditions, and to detect the possible structural deterioration over the age of structures. Monitoring systems are also employed as the basis of investigation and decision making for structural repair and/or retrofit when required. More recent interest has been to further extend application of monitoring to facilitate operation and maintenance, through rationalization of risk and asset management by utilizing monitoring data. The paper describes strategies and several examples of monitoring system and lessons learned from structural monitoring of long-span bridges in Japan.