• Journal of Korean Society of Water and Wastewater
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• v.25 no.4
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• pp.611-616
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• 2011

The impacts of ultrasonic pretreatment on the biodegradability of domestic sewage sludge were evaluated through a series of anaerobic digestion experiments in batch system. The gas and methane production from the sludge samples pretreated by an ultrasonic tool with different durations were measured with time. Although the biogas production increased with the extent of sludge solubilization and the period of ultrasonic pretreatment, the enhancement of sludge biodegradability was much more sensitive to the pretreatment for the relatively short periods. Most of the enhanced biodegradability by the pretreatment was appeared in the early stage of anaerobic digestion, less than 6 days. The maximum biogas production per day was observed between 4 to 6 days when the sludge was pretreated less than 10 minutes while it was obtained in the beginning for the sludge pretreated longer periods. The results suggest that the repeated alternation of low strength ultrasonic pretreatment and anaerobic digestion may be more effective than the combination of one time pretreatment for a relatively long period and following anaerobic digestion.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.8
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• pp.1347-1354
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• 2016

This paper presents optimal operational scheduling model and economic assessment of Li-ion battery energy storage systems installed in non-residential customers. The operation schedule of a BESS is determined to minimize electric bill, which is composed of demand and energy charges. Dynamic programming is introduced to solve the nonlinear optimization problem. Based on the optimal operation schedule result, the economics of a BESS are evaluated in the investor and the social perspective respectively. Calculated benefits in the investor or customer perspective are the savings of demand charge, energy charge, and related taxes. The social benefits include fuel cost savings of generating units, construction deferral effects of the generation capacity and T&D infra, and incremental CO2 emission cost impacts, etc. Case studies are applied to an large industrial customer that shows similarly repeated load patterns according to days of the week.

• The Bulletin of The Korean Astronomical Society
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• v.44 no.2
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• pp.60.4-60.4
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• 2019

Small bodies in the solar system are pristine leftovers of planetesimals since the formation epoch (~4.6 Gyr ago). After the formation, icy planetesimals have been preserved in the distant cold place beyond 30 au (i.e., Trans-Neptunian region) until recently without any catastrophic processes but have just been injected into inner region (<~5 au from the Sun) to be observed as comets. On the contrary, asteroids are rocky primitive objects (although some of them contains icy volatiles) distributing in the mainbelt between Mars and Jupiter orbits. Because of frequent encounters in the mainbelt, asteroids have experienced a number of repeated impacts until the present day. Namely, it is important to investigate thermal alternation process of cometary volatiles and refractories in the solar radiation field, whereas collisional and subsequence phenomena of asteroidal bodies. Although recent spacecraft observations revealed the physical natures on the surfaces of comets and asteroids, their interiors still remain largely unexplored. It is likely that a sudden brightening of a comet is associated with rapid sublimation of internal CO and CO2 or phase transition of amorphous H2O. An episodic dust ejection from an asteroid is causally related to an impact among asteroids, sudden sublimation of remaining subsurficial volatiles, etc. Because these transient phenomena provide rare opportunities to investigate their interiors, immediate observations using any optical instruments are particular important. In my presentation, I will review some examples of such transient phenomena in the solar system and propose possible collaborative research using the Korean Small Telescope Network.

• Journal of Life Science
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• v.31 no.4
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• pp.442-451
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• 2021

Microplastics are fragments of any type of plastic with a size less than 5 mm. Ocean pollution by microplastics is now a worldwide concern in relation to marine ecosystems and human health. The widespread contamination by microplastics means that they can be ingested by and accumulated in diverse species of wildlife, such as fish, mussels, oysters, clams, and scallops. Once ingested, the microplastics can be observed in the intestines, liver, and kidney, and even in the brain. Seafood is one of the major sources of protein intake in humans; therefore, seafood consumption could be pathway for human microplastics exposure. Accumulating evidence indicates that repeated oral exposure to microplastics induces pathologic and functional changes in the reproductive, cardiac, gastrointestinal, endocrine, and even nervous systems of rodents. Maternal exposure to microplastics during gestation and lactation alters metabolic homeostasis in the offspring. Given that seafood provides more than 20% of the total protein intake by over 310 million people worldwide, a reasonable assumption is that microplastics could be substantially accumulated in the human body and impair physiological function. In this review, we have summarized the current status of microplastics contamination in the ocean, their accumulation and toxicities in marine animals and rodents, their exposure to humans, and their potential impacts on human health.

• Asia pacific journal of information systems
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• v.10 no.2
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• pp.71-95
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• 2000

Despite repeated exhortation about the importance of social and human dimensions of systems development, socio-organizational issues continue to be neglected and ignored in the current information systems practice. A review of the human information processing literature suggests that the reasons for this continuing lack of attention to social issues may be found in the limitations of human cognition and information processing capacities. Bostrom and Heinen(1978) and Kumar and Bjorn-Anderson(1990) also suggest that the inadequate attention to social problems and issues by the analyst could originate from the analysts limited problem perception. This research explores how the representation forms of information systems(IS) methodology used in understanding and modeling the problem situation affect such systems development problem perception. Typically, a system development methodology prescribes the use of system models(i.e., system representations) to understand, analyze, evaluate, and design the information system. Given the size and complexity of information systems, and the abstraction and simplification underlying the modeling process, system representations usually depict only a limited set of aspects of the system. Thus, a methodology whose representations are limited to technical aspects will tend to limit the analyst's perspective to a technical one only(Kumar & Welke, 1990). Following the same line of argument, in contrast, it is the conjecture of this study that a methodology which specifies both social and technical aspects of IS development will help the analyst develop a more comprehensive view of the IS problem domain. Based on the above concept, a theoretical model was first developed which explained the systems analysts cognitive process. Drawing on this model, a research model was developed hypothesizing the impacts of representation forms on problem identification. The model was tested using a laboratory experiment with 70 individual subjects. A special computer software was developed with a hypermedia authoring tool to conduct the experiments in order to avoid experimenter biases and to maintain consistency in administrating repeated experiments. The program, designed to replace the experimenter, consisted of functions such as presenting the subjects with problem material, asking the subjects questions, and saving the typed answers of the subjects. The results indicate that representation forms strongly influence problem identification. It was found that the use of the socio-technical representation form led to the findings of more social problems than the use of technical representation form. The results imply significant effects of representation forms on problem findings and also suggest that the use of adequate representation forms may help overcome dysfunctional effects of our limited information processing capacity.

• Journal of Korean Academy of Nursing
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• v.45 no.2
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• pp.221-230
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• 2015

Purpose: This study was done to examine how laughter therapy impacts serotonin levels, QOL and depression in middle-aged women and to perform a path analysis for verification of the effects. Methods: A quasi-experimental study employing a nonequivalent control group and pre-post design was conducted. Participants were 64 middle-aged women (control=14 and experimental=50 in 3 groups according to level of depression). The intervention was conducted five times a week for a period of 2 weeks and the data analysis was conducted using repeated measures ANOVA, ANCOVA and LISREL. Results: Results showed that pre serotonin and QOL in women with severe depression were the lowest. Serotonin in the experimental groups increased after the 10th intervention (p=.006) and the rise was the highest in the group with severe depression (p=.001). Depression in all groups decreased after the 5th intervention (p=.022) and the biggest decline was observed in group with severe depression (p=.007). QOL of the moderate and severe groups increased after the 10th intervention (p=.049), and the increase rate was highest in group with severe depression (p<.006). Path analysis revealed that laughter therapy did not directly affect depression, but its effect was indirectly meditated through serotonin variation (p<.001). Conclusion: Results indicate that serotonin activation through laughter therapy can help middle-aged women by lessening depression and providing important grounds for depression control.

• KIEAE Journal
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• v.12 no.4
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• pp.13-19
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• 2012

The Earth's surface temperature still continues to rise, and extreme weather phenomena such as heat waves, drought, and precipitation have been repeated every year. It is reported that international communities attribute the main cause of the Earth's surface temperature rise to the excessive use of the fossil energy. Recently, the damage caused by climate change is getting worse, and the place where we live is suffering the most. Cities have been continuously growing not only meeting the basic functions of human habitation, work and leisure but also being places for various economic and social activities. But Cities, the victims of climate change, have grown only considering human needs and convenience rather than predicting their physical and ecological systems(Albedo effects, urban microclimate, resources and energy of the circulatory system, etc). In other words, the cities offer the cause of the problems of climate change, and even worsen the extreme weather phenomena without coping with them. Therefore, it is urgent priorities to protect the climate, to prevent the causes of the extreme weather phenomena and to enhance the adaptive capacity for the worse weather events. This study is to derive the concept for adapting to these climate changes which can make cities escape from exposure to these climate change impacts and make themselves safer places to live. And it analyzes some European cities and present developing models to implement planning methods. In this study, the concept of the climate adaptive cities will be suggested to prepare the adaptation measures for urban planners, and climate change adaptation models will be presented by analyzing some preliminary cases.

• Journal of Digital Convergence
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• v.18 no.6
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• pp.187-196
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• 2020

We tried to do research on main views(risk and knowledge-based) and propose user knowledge as a factor to be managed in order to strengthen the performance. This study empirically analyzed the user-related and project management risk that affect the IT project performance, and verified user knowledge as a moderating variable. The survey was conducted for respondents who have experience on IT Project of public sector and data were analyzed by Smart PLS 3.0. The results show that low user-related and project management risks have a positive effect on performance. In addition, user knowledge has been shown to enhance the impact of two risks on performance. These findings are meaningful in that they emphasize the importance of user knowledge in public-sector IT projects, as well as the repeated verification of integrated research results.

• Journal of the Korea Convergence Society
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• v.11 no.4
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• pp.255-264
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• 2020

This research empirical explores impacts of performance information use of decision makers in distributing financial resources. Based on theoretical review and previous researches, we organized three scenarios of general public administration, economic policy, and environmental policy and investigated the difference in budget distribution between measured information and simple information of success or failure by randomly divided experimental and control groups who are not experienced bureaucratic processed. The results indicate that experimental group judge by using performance information with numeric indicators and has more diversified patterns than control group. We suggest that repeated experiments including bureaucratic members to reduce bias of expertness and generalize the decision making models using performance information in future researches.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.21 no.2
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• pp.19-27
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• 2008

Objective : The side effect of prolonged use of topical corticosteroids to skin is well-known. Moreover, resent studies have shown that prolonged use of systemic corticosteroids also negatively impacts skin barrier function. Corticosteroids have a major role in the practical management of many variable conditions. So, it is important to find the drug or the method which could protect the skin from the damage caused by corticosteroids. At former study, we investigated that Insamyangyoung-tang has some effect on skin barrier function of DNCB induced contact dermatitis hairless mice. So, this study was performed to research the effect of Insamyangyoung-tang on the TEWL with high dose steroid injected hairless mice. Method : Hairless mice were divided into 4 groups ; Control group, Group A, Group B and Group C. All groups were injected triamcinolone O.4mg for 10 times. Control group was medicated distilled water during the experimental period. Group A was medicated distilled water for 5 days before the $1^{st}$ injection day, and then medicated Insamyangyoung-tang extract during the experimental period. Group B was medicated Insamyangyoung-tang extract for 5 days before the $1^{st}$ injection day, and then medicated distilled water during the experimental period. Group C was medicated Insamyangyoung-tang extract for 5 days before the $1^{st}$ injection day, and then medicated Insamyangyoung-tang extract during the experimental period. TEWL of each group was measured for 5 times. After the $10^{th}$ injection, the tissue sample was made and the damage of epithelial cell was examined. Statistical significance was set at p<0.05 by using non parametric methods and repeated-anova.. Results : Group C showed significant effect on TEWL change of hairless mice evoked by triamcinolone injection. Group A and Group B also showed some effect, but there was no statistical significance.