• Journal of Korea Water Resources Association
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• v.56 no.11
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• pp.705-720
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• 2023

In South Korea, ongoing incidents related to drinking water quality have eroded consumer trust. Specifically, beyond quality incidents, there have been complaints about taste, odor, and other issues stemming from the presence of chlorine. To address this, water service operators are employing various management strategies from both temporal (scheduling) and spatial (rechlorination) perspectives to ensure uniform and safe distribution of chlorine residuals. In this study, we focus on the optimal monthly management of chlorine residuals, based on water distribution network analysis. Water quality reaction coefficients, including bulk fluid and wall reaction coefficients, were estimated through lab-scale tests and EPANET water quality simulations, respectively, accounting for temperature variations in a large-scale water distribution network. Utilizing these estimated coefficients, we examined the monthly variations in chlorine residual distribution under different chlorine injection conditions. The results indicate that the efficient concentration for chlorine injection, which satisfies the residual chlorine limit range, varies with temperature changes. Consequently, it is imperative to establish a specific and quantitative chlorine injection plan that considers the accurate spatial distribution of monthly chlorine residuals.

• Pediatric Infection and Vaccine
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• v.4 no.1
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• pp.97-105
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• 1997

Purpose : Aseptic meningitis mainly caused by enterovirus is common in pediatric population especially during summer & fall. Most of pediatric patients restore their health without any complications with proper management. Between May to August of 1996, Masan and surrounding areas of the Kyoungsangnamdo were epidemic areas for the aseptic meningitis. The purpose of this study was to determine causative virus and describe correlation between disease and clinical symptoms in aseptic meningitis patients and those with fever and characteristic rashes without apparent meningitis symptoms. Methods : Between May to August, 1996, 57 patients with high fever and characteristic feature of rashes were reviewed. From 22 cerebrospinal fluid & 57 stool obtained specimens, viral culture and detection of enterovirus RNA were conducted. Collected specimens were kept in $-30^{\circ}C$ environment until sending of specimens to labortory. The virus identified through indirect immunofluorescence. RT-PCR method was used to identify enterovirus RNA in cerebralspinal fluid. Results : 1) One hundred fifty five pediatric patients with viral infection required hospitalization. Disease occurred higher rate in male than female with ratio of 1.94:1. Examined patients' age ranged from 15days old to 15years old. But most of patients(74.8%) were under age of 5years old. The time of occurrence was between May to August of 1996. 2) All patients had high fever and physical symptoms in those patients include headache, vomiting, abdominal pain, diarrhea, and rashes. The rashes observed mainly in patients under age of 4 years and were predominantly commom patients under age of 18 months olds)<0.001). 3) Between sampled patients and non-sampled patients, clinical course was similar. Echovirus type 9 was cultivated in 41 out of 57 cases of collected stool specimens. RT-PCR that used on CSF showed positive results in 10 out of 22 cases. Three cases of positive cultivated of positive results in RT-PCR were echovirus type 9. Conclusions : Echovirus type 9 was thought to be the causative agent of aseptic meningitis that was prevalent throughout mid areas of Kyoungsangnamdo from May to August, 1996. Additionally causative agent that responsible for high fever with rashes without meningitis symptoms also thought to be the same echovirus type 9.

• Journal of the Korean Institute of Landscape Architecture
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• v.39 no.4
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• pp.49-59
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• 2011

This study is a reinterpretation of characteristics of public space in contemporary cities with a view to liminal space. The conditions of pubic space now cannot be captured through the existing discourses of publicness, and public space. The basic premise of the study is that the idea of liminal space or liminality is useful to grasp the fluid and hybrid attribute of public space in contemporary cities. Liminal space, originally from anthropological studies, is the intermingled stage between two realms and the sustained period of the ritual. The idea has been widely used for various cultural phenomenon and spatial experiences. A literature review on public space and liminal space was carried out. Cases pertaining to public space with a view to liminal space were examined and discussed in detail. Through the careful reading of several public spaces with an angle toward liminal space, the new perspective toward public space will be drawn out. First, we need to emphasize the fluid spectrum of public space rather than the serial stage such as the public, the semi-public, the semi-private, and the private. Second, the idea will contribute to understanding the flexible state depending upon time. What we can learn from case studies is the volatile characteristics in public space as a common phenomenon support its vitality. This interpretation will contribute to the perception of a new horizon of public space. The nature of public space is unpredictable and free. In reality, the spectrum of public space will expand and fluctuate. Ironically, public space can be vitalized through enhancing and activating the private space. The intimate and complicated interface between the two realms is a key issue. The boundary of public space might be redefined to embrace the flexible the fragile nature of changing public space. These research implications will guide the thoughtful design and management of pubic space.

• Journal of Internet Computing and Services
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• v.16 no.1
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• pp.57-65
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• 2015

As information technology fusion is accelerated, the researches to improve the quality and productivity of crops inside a plant factory actively progress. Advanced growth environment management technology that can provide thermal environment and air flow suited to the growth of crops and considering the characteristics inside a facility is necessary to maximize productivity inside a plant factory. Currently running plant factories are designed to rely on experience or personal judgment; hence, design and operation technology specific to plant factories are not established, inherently producing problems such as uneven crop production due to the deviation of temperature and air flow and additional increases in energy consumption after prolonged cultivation. The optimization process has to be set up in advance for the arrangement of air flow devices and operation technology using computational fluid dynamics (CFD) during the design stage of a facility for plant factories to resolve the problems. In this study, the optimum arrangement and air flow of air circulation fans were investigated to save energy while minimizing temperature deviation at each point inside a plant factory using CFD. The condition for simulation was categorized into a total of 12 types according to installation location, quantity, and air flow changes in air circulation fans. Also, the variables of boundary conditions for simulation were set in the same level. The analysis results for each case showed that an average temperature of 296.33K matching with a set temperature and average air flow velocity of 0.51m/s suiting plant growth were well-maintained under Case 4 condition wherein two sets of air circulation fans were installed at the upper part of plant cultivation beds. Further, control of air circulation fan set under Case D yielded the most excellent results from Case D-3 conditions wherein air velocity at the outlet was adjusted to 2.9m/s.

• Tuberculosis and Respiratory Diseases
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• v.48 no.3
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• pp.357-364
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• 2000

Background : Complicated exudative pleural fluid collections have traditionally been treated by either closed tube thoracostomy drainage or by open surgical drainage. Complete drainage is important in order to control pleural sepsis, restore pulmonary function, and entrapment. Recently intracavitary fibrinolytic therapy has been advocated as a method to facillitate drainage of complicated exudative pleural effusion and to allow enzymatic debridemant of the restrictive fibrinous sheets covering the pleural surface. The purpose of this study is to prospectively evaluate the effects of image-guided catheter drainage with high dose urokinase(UK) instillation in the treatment of complicated pleural effusions. Patients : Twenty complicated pleural effusion patients that poorly respond to image-guided drainage were allocated to receive UK. There were 8 pneumonia and 12 tuberculosis. Methods : Drugs were diluted in 250 mL normal saline and were infused intrapleurally through the chest tube or pig-tail catheter in a daily dose of 250,000 IU of UK. Response was assessed by clinical outcome, fluid drainage, chest radiography, pleural ultrasound and/or computed tomography. Results : The mean UK instillation time was $1.63{\pm}0.10$. The mean volume drained UK instillation was $381.3{\pm}314.4\;mL$, and post-UK was $321.6{\pm}489.5\;mL$. The follow up duration after UK therapy was mean $212.9{\pm}194.5$ days. We had successful results in 19 cases (95.0%). There were 12 pleural thickenings (60.0%), 2 markedly decreased effusions (10.0%) and 5 cases of no thickening or effusion. There was recurrence after treatment in only one patient(5%) with complicated pleural effusiondue to tuberculosis. Conclusions : Image-guided drainage with high dose UK instillation (250,000 U/day) in complicated pleural effusion is a safe and more effective method than closed thoracostomy drainage. And this management, in turn, can obviate surgery in most cases.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.9 no.1
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• pp.23-30
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• 2006

Purpose: The estimation of fluid deficit is crucial to the proper management of dehydrated children. Without well-documented serial weights on the same scale, the estimation of any given child's fluid deficit is imprecise and dependent largely on subjective clinical criteria. Despite the abundance of literature on clinical and laboratory evaluation of dehydration, few studies have focused on serum uric acid. So, we examined the usefulness of scrum uric acid in gastroenteritis patients with dehydration. Methods: Medical records of 90 gastroenteritis patients were retrospectively reviewed. By the body weight loss, we classified patients with mild, moderate, and severe dehydration groups. We studied the relevance of laboratory data (BUN, creatinine, serum bicarbonate, glucose, urine specific gravity, and uric acid) with dehydration. Results: 54 children (60%) were dehydrated mildly, 24 (26%) dehydrated and moderately, and 12 (14%) dehydrated severely. Statistically significant differences in BUN, creatinine, serum bicarbonate, glucose, and urine specific gravity could not be observed. But there was significant relationship between uric acid and the degree of dehydration. Data analysis suggested that the level of 7.0 mg/dL is the best cut-off value for predicting the development of moderate or severe dehydration. At this cut-off value, the sensitivity and specificity were 66.6% and 87.1%. Conclusion: Our study supports that the measurement of serum uric acid with traditional scale is useful for predicting the development of dehydration. But, in order 10 be used as the indicator for proper treatment at an earlier stage, further validation about serum uric acid is necessary.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.16 no.12
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• pp.1234-1268
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• 2004

A review on the papers published in the Korean Journal of Air-Conditioning and Refrigerating Engineering in 2002 and 2003 has been carried out. Focus has been put on current status of research in the aspect of heating, cooling, air-conditioning, ventilation, sanitation and building environment/design. The conclusions are as follows. (1) Most of fundamental studies on fluid flow were related with heat transportation in diverse facilities. Drop formation and rivulet flow on solid surfaces were interesting topics related with condensation augmentation. Research on micro environment considering flow, heat transfer, humidity was also interesting to promote comfortable living environment. It can be extended considering biological aspects. Development of fans and blowers of high performance and low noise were continuing research topics. Well developed CFD technologies were widely applied for analysis and design of various facilities and their systems. (2) Heat transfer characteristics of enhanced finned tube heat exchangers and heat sinks were extensively investigated. Experimental studies on the boiling heat transfer, vortex generators, fluidized bed heat exchangers, and frosting and defrosting characteristics were also conducted. In addition, the numerical simulations on various heat exchangers were performed and reported to show heat transfer characteristics and performance of the heat exchanger. (3) A review of the recent studies shows that the performance analysis of heat pump have been made by various simulations and experiments. Progresses have been made specifically on the multi-type heat pump systems and other heat pump systems in which exhaust energy is utilized. The performance characteristics of heat pipe have been studied numerically and experimentally, which proves the validity of the developed simulation programs. The effect of various factors on the heat pipe performance has also been examined. Studies of the ice storage system have been focused on the operational characteristics of the system and on the basics of thermal storage materials. Researches into the phase change have been carried out steadily. Several papers deal with the cycle analysis of a few thermodynamic systems which are very useful in the field of air-conditioning and refrigeration. (4) Recent studies on refrigeration and air-conditioning systems have focused on the system performance and efficiency enhancement when new alternative refrigerants are applied. Heat transfer characteristics during evaporation and condensation are investigated for several tube shapes and new alternative refrigerants including natural refrigerants. Efficiency of various compressors and performance of new expansion devices are also dealt with for better design of refrigeration/air conditioning system. In addition to the studies related with thermophysical properties of refrigerant mixtures, studies on new refrigerants are also carried out. It should be noted that the researches on two-phase flow are constantly carried out. (5) A review of the recent studies on absorption refrigeration system indicates that heat and mass transfer enhancement is the key factor in improving the system performance. Various experiments have been carried out and diverse simulation models have been presented. Study on the small scale absorption refrigeration system draws a new attention. Cooling tower was also the research object in the respect of enhancement its efficiency, and performance analysis and optimization was carried out. (6) Based on a review of recent studies on indoor thermal environment and building service systems, it is noticed that research issues have mainly focused on several innovative systems such as personal environmental modules, air-barrier type perimeterless system with UFAC, radiant floor cooling system, etc. New approaches are highlighted for improving indoor environmental conditions and minimizing energy consumption, various activities of building energy management and cost-benefit analysis for economic evaluation.

• Journal of Bio-Environment Control
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• v.32 no.1
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• pp.48-56
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• 2023

High-pressure sodium (HPS) lamps have been widely used as a useful supplemental light source to emit sufficient photosynthetically active radiation and provide a radiant heat, which contribute the heat requirement in greenhouses. The objective of this study to analyze the thermal characteristics of HPS lamp and thermal behavior in supplemented greenhouse, and evaluate the performance of a horizontal leaf temperature of sweet pepper plants using computational fluid dynamics (CFD) simulation. We simulated horizontal leaf temperature on upper canopy according to three growth stage scenarios, which represented 1.0, 1.6, and 2.2 plant height, respectively. We also measured vertical leaf and air temperature accompanied by heat generation of HPS lamps. There was large leaf to air temperature differential due to non-uniformity in temperature. In our numerical calculation, thermal energy of HPS lamps contributed of 50.1% the total heat requirement on Dec. 2022. The CFD model was validated by comparing measured and simulated data at the same operating condition. Mean absolute error and root mean square error were below 0.5, which means the CFD simulation values were highly accurate. Our result about vertical leaf and air temperature can be used in decision making for efficient thermal energy management and crop growth.

• Tuberculosis and Respiratory Diseases
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• v.44 no.1
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• pp.85-92
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• 1997

Background : The standard treatment of recurrent, symptomatic malignant pleural effusion is intrapleural instillation of a chemical agent in an attempt to achieve a sterile inflammation and pleurodesis. There are many drugs used as pleural sclerosing agents, but the efficiency and side effects are different. The present study was undertaken to compare the commonly used drugs, doxycycline and bleomycin. Methods : Thirty-four patients with malignant pleural effusion who needed repeated thoracentesis were randomized to receive treatment with intrapleural instillation of doxycycline or bleomycin Fluid volumes before and after pleurodesis, drainge time, and side effects were analyzed, and the response to treatment was evaluated by clinical examination and chest radiography during admission in the hospital. Also median survival rime were evaluated according to the responses. Results : The response rate was higher in the patients receiving doxycycline than in those receiving bleomycin (87.5% vs 50.0%, p=0.02), and fever, nausea and vomiting were more common in the patients receiving bleomycin. The median survival time was significantly longer in the patients who responded to the sclerotherapy regardless of sclerosing agents. Conclusions : Chemical pleurodesis with doxycycline or bleomycin could reduce or stop pleural effusions and prolong the median survival rimes in these patients. Doxycycline appeared to be more efficient as sclerosing agent than bleomycin in the short-term follow-up periods. But a prospective study with a larger number of patients is warranted.

• Journal of Bio-Environment Control
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• v.27 no.2
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• pp.147-157
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• 2018

With the rapid development of the 4th industrial revolution, the large-sized facilities of agriculture have been developed with high-technologies. However, it is difficult to maintain the optimum environment in large-sized facilities. Although it is essential to control micro-climate properly in large-sized facilities, there are a lot of problems to utilize high-technologies and equipment because of insufficient education for farmers. Most farms have limitations to access to their farm because of prevention of epidemics, exposure of management know-how, and so on. Especially, it is difficult to understand internal environmental factors (airflow, temperature, humidity, etc.) for farmers because these factors are invisible. Recently, Virtual reality technology which allows users to experience various phenomena directly is attracting attention. Virtual reality is very useful technology to visualize airflow and temperature distribution and so on. However, there is no cases applied this technology to agricultural facilities. In this study, research trends of virtual reality in various fields were investigated. In particular, the limitation and possibility of virtual reality technology were analyzed for educating farmers. Finally, the development of virtual reality contents for smart-farm facility were suggested.