• Journal of Environmental Health Sciences
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• v.39 no.1
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• pp.83-89
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• 2013

Objectives: The purpose of this experiment was to illuminate the relationship between the phosphorus removal rate of unit operation and the phosphorus removal rate of phosphorus volume loading in the Ferrous Nutrient Removal process, which consists of an anoxic basin, oxic basin, and iron precipitation apparatus. Methods: This study was conducted in order to improve the effect of nitrogen and phosphorus removal in domestic wastewater using the FNR (Ferrous Nutrient Removal) process which features an iron precipitation reactor in anoxic and oxic basins. The average concentration of TN and TP was analyzed in a pilot plant ($50m^3/day$). Results: The removal rate of T-N and T-P were 66.5% and 92.8%, respectively. The $NH_3-N$ concentration of effluent was 2.62 mg/l with nitrification in the oxic basin even though the influent was 17.7 mg/l. The $NO_3$-N concentration of effluent was 5.83 mg/l through nitrification in oxic basin even though the influent and anoxic basin were 0.82 mg/l and 1.00 mg/l, respectively. The specific nitrification of the oxic basin ($mg.NH_3$-Nremoved/gMLVSSd) was 16.5 and specific de-nitrification ($mg.NO_3$-Nremoved/gMLVSSd) was 90.8. The T-P removal rate was higher in the oxic basin as T-P of influent was consumed at a rate of 56.3% in the anoxic basin but at 90.3% in the oxic basin. The TP removal rate (mg.TP/g.MLSS.d) ranged from 2.01 to 4.67 (3.06) as the volume loading of T-P was increased, Conclusions: The test results showed that the electrolysis of iron is an effective method of phosphorus removal. Regardless of the temperature and organic matter content of the influent, the quality of phosphorus in the treated water was both relatively stable and high due to the high removal efficiency. Nitrogen removal efficiency was 66.5% because organic matter from the influent serves as a carbon source in the anoxic basin.

• Journal of the Korean Institute of Landscape Architecture
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• v.36 no.5
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• pp.26-34
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• 2008

This study was conducted to investigate the correlation between golfer satisfaction and the diverse variables of golf course design and operation from the golfer's point of view. It was intended to reflect the various expectations and desires of golfers regarding golf course design and operation. The study was conducted on 119 golf courses in Korea, and 309 questionnaires were collected and analyzed. Results are summarized as follows. First, the most influential operational service variables on golfer satisfaction were "appearance of the golf courses", followed by "staff service", and "greens fee". Second, the most influential course design and maintenance factor variables on satisfaction were "course maintenance status", "teeing ground characteristics", and "landscape architecture". Third, based on the results shown in these two areas, a linear regression analysis was conducted to synthetically explain "operational service" variables and "course design and maintenance" variables. As a result, it was found that the explanation power of the synthetic model was 36.5%, and a model appropriateness test was found to be positive. As a result of a regression analysis of the synthetic model affecting golfer satisfaction, the most influential factors were "course maintenance status" followed by "landscape architecture", "tee characteristics", and "staff service". Regarding coefficient values, course maintenance status had an influence of 21.8% followed by landscape architecture at 20%, tee characteristics at 17.7%, and staff service at 15.5%. These results were found to be different from preceding studies that emphasized golf course operational service.

• Archives of design research
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• v.17 no.1
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• pp.49-62
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• 2004

Due to the recent surge of wireless Internet and concurrent development of the end user terminal devices having standardized graphical user interface(GUI) and unified operation mechanism for better interactivity in information representation and ease of use, various efforts on the improvement of GUI is widely recognized as one of the key factors that will usher in the next stages of the wireless Internet for the users. Especially, improved usability along with unique visual effect are considered to be the key elements for GUI considering the rapid improvement of the resolution and color on the end user handset devices; thus, the study and research on the subject of GUI is expected to increase along with the wireless Internet using smart phones. User interface of the wires Internet end user handsets will have a definite and significant effect on the user interaction as well as productivity. Domestically, wireless Internet service providers and GUI design companies are making various efforts in producing a common GUI models for standardized operation scheme and improved graphical display capabilities of the hand phones, PDAs and smart phones. In the study, Nokia 3650 model and Microsoft Orange SPV model were chosen as test devices for usability comparison and data collection to collect directional benchmark data in developing next generation smart phone user interface integrating PDAs and phones. The mail purpose of this study is to achieve the most efficient user accessibility to WAP menu through intensive focus on developing WIPI WAP menu having most effective usability for the users in their twenties and thirties. The result of this study can also be used as the base research materials for WAP service development, VM browser development and PDA browser development. The result of this study along with the evaluation model is expected to provide effective analysis materials on the subject of user interface to the developers of the wireless Internet user devices, GUI designers and service planners while short listing key factors to consider in developing smart phones therefore serving as the GUI guideline of WIPI phones.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.1
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• pp.61-69
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• 2020

This study examined the braking characteristics of a heavy haul freight train with P4a distribution valves applied to domestic high-speed freight trains. A freight train was composed of 50 cars, which is twice the normal operation. A braking test was performed to confirm the characteristics of the braking of a heavy haul. The brake cylinder pressures were measured for emergency and service braking on the 1st, 10th, 20th, 30th, and 50th cars. Because the brake signal is transmitted to the pressure through the braking tube connected to the end of the train, the rear vehicle is braking later than the vehicle ahead. Therefore, it is necessary to predict the brake pressures in all cars in a train to supplement the results of the limited tests and calculate the braking distance. The pressure in each car was determined using empirical models of linear interpolation, stepwise, and exponential models, which provided reliable information. The predictive results of the empirical models were compared with the measured results, and the exponential model was predicted relatively accurately. These results are expected to contribute to the safe operation of heavy haul freight trains and can be used to predict the braking distance and calculate the level of impact between vehicles during braking.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.8
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• pp.1802-1809
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• 2009

Abstract The typical distribution systems have the power flow from distribution substations (sources) to customers (load) only as one direction. However, in the case where distributed generations (DG) such as PV system and wind power systems are connected to distribution systems, the DG output variations to distribution systems, so called reverse power flow, may cause the bi-directional power flow. So, the reverse power flow has severe impacts on typical power system, for example power quality problems, protection coordination problems, and so on. Especially, protection devices (sectionalizer) in primary feeder of distribution system interconnected with distributed generations may cause problems of malfunction, and then many customers could have problems like an interruption. So, this paper presents the bi-directional operation algorithm of protection devices to overcome the problems like mal-function. And, also this paper shows the effectiveness of proposed method by using both PSCAD/EMTDC software and test facility of protection devices to simulate the field distribution systems.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.1
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• pp.369-377
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• 2013

This paper deals with the state of charge(SOC) and life cycle evaluation algorithm for lead-acid battery, which is essential factor of the electric vehicle(EV) and the stabilization of renewable energy in the smart grid. In order to perform the effective operation of the lead-acid battery, SOC and life cycle evaluation algorithm is required. Specific gravity with the change of electrolyte temperature inside battery case should be obtained to evaluate the SOC of lead-acid battery, however it is difficult to measure the electrolyte temperature of sealed type lead-acid battery. To overcome this problem, this paper proposes the equation of thermal transmission to compensate internal temperature of the lead-acid battery. Also, it is difficult to exactly evaluate the life cycle of battery, depending on the operation conditions of lead-acid battery such as charging and discharging state, self discharging rate and environmental issue. In order to solve the problem, this paper presents the concept for gravity accumulation of charge and discharge cycle, which is the value converted at $20^{\circ}C$. By using the proposed algorithm, this paper propose the test device based on the Labview software. The simulation results show that it is a practical tool for the maintenance of lead-acid battery in the field of industry.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.2
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• pp.1036-1043
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• 2014

The installation of PV system to the power distribution system is being increased as one of solutions for environmental pollution and energy crisis. Because the output efficiency of PV system is getting decreased because of the aging phenomenon and several operation obstacles, the technology development of output prediction and state diagnosis of PV modules are required in order to improve operation performance of PV modules. The conventional methods for output prediction by considering various parameters and standard test condition values of PV modules may have difficult and complex computation procedure and also their prediction values may produce large error. To overcome these problems, this paper proposes an optimal prediction algorithm and state diagnosis algorithm of PV modules by using least square methods of linear regression analysis. In addition, this paper presents a state diagnosis evaluation system of PV modules based on the proposed optimal algorithms of PV modules. From the simulation results of proposed evaluation system, it is confirmed that the proposed algorithms is a practical tool for state diagnosis of PV modules.

• Journal of the Korean Institute of Gas
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• v.13 no.6
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• pp.34-38
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• 2009

Nitrous oxide, which is used as an anesthetic gas, has been shown to be a chronic health hazard. It is necessary to monitor and control the nitrous oxide exposure of the operating theaters staff. In this study, N2O exposure level of the operating nurses is assessed with a GC-ECD. The nitrous oxide gas is collected on a molecular sieve 5A contained in a glass tube and desorbed for 12 hours at $100^{\circ}C$ in heating block. As a result of the test using GC-ECD, calibration curve's $R^2$ of $N_2O$ is 0.9992, LOD is $0.96{\mu}g$/injection, LOQ is $3.21{\mu}g$/injection, desorption efficiency is 94.78 4.50% in average and break through is within 10% compared with the concentration. The average concentration before operation is 5.12ppm and it is 42.3ppm during operation. There are a significant difference showing that the P value is lower than 0.05. Assessing exposure level to nitrous oxide based on nurses' working positions, the exposure levels do not show significant difference( P>0.005). And $N_2O$ in active sampling method is higher than passive sampling method(P<0.05).

• Journal of Soil and Groundwater Environment
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• v.10 no.4
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• pp.54-61
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• 2005

An aquifer thermal energy storage (ATES) system can be very cost-effective and renewable energy sources, depending on site-specific parameters and load characteristics. In order to develop the ATES system which has certain hydrogeological characteristics, understanding the thermohydraulic process of an aquifer is necessary for a proper design of an aquifer heat storage system under given conditions. The thermohydraulic transfer for heat storage was simulated according to two sets of simple pumping and waste water reinjection scenarios of groundwater heat pump system operation in a two-layered aquifer model. In the first set of the scenarios, the movement of the thermal front and groundwater level was simulated by changing the locations of injection and pumping wells in a seasonal cycle. However, in the second set the simulation was performed in the state of fixing the locations of pumping and injection wells. After 365 days simulation period, the shape of temperature distribution was highly dependent on the injected water temperature and the distance from the injection well. A small temperature change appeared on the surface compared to other simulated temperature distributions of 30 and 50 m depths. The porosity and groundwater flow characteristics of each layer sensitively affected the heat transfer. The groundwater levels and temperature changes in injection and pumping wells were monitored and the thermal interference between the wells was analyzed to test the effectiveness of the heat pump operation method applied.

• Archives of Plastic Surgery
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• v.36 no.5
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• pp.611-616
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• 2009

Purpose: The rate of fistulas occuring followed by resection of oral cavity, oropharyngeal, hypopharyngeal, and laryngeal cancer are reported to be 9 ~ 23% according to various documents. Neglected treatment of the fistula can result in a setback in proper treatment with restrictions in oral intake leading to delayed return to daily life. Furthurmore, in severe cases, it may injure important vessels and adjacent structures of the neck area. The author reviewed previously reported cases of treatment methods for fistulas recurring after diverse head and neck operations and with sharing the treatment experiments of our patients, we tried to present a treatment algorism for different fistula types. Methods: Our study was based on retrograde analysis of 64 patients who were clinically diagnosed with fistula after operation for cancer of the head and neck from 1997 to 2008 at Severance Hospital. Their primary sites of cancer were 8 oral cavity, 22 oropharynx, 25 hypopharynx, and 9 larynx. The patients were aged 45 to 75 years and the male to female ratio was 11 to 1. The patient's operation records and progress notes were evaluated for determination of degree of fistula and treatment methods. Results: Most fistulas were clinically suspected after postoperative 5 days and symptoms noted for detection of the fistula were erythema, purulent discharge, edema, tenderness, and fluctuation. The fistula was definitely diagnosed at postoperative 2 weeks with barium test and treatment method ranging from conservative management to operative procedure were applied to each patients. Total 21 patients were managed with conservative protocol. In 15 cases, direct repair of the fistula was done and more stable repair of the fistula was possible with using of TachoComb$^{(R)}$. Pharyngostoma was performed in 14 patients. Among them, 4 patients healed spontaneously, 5 patients were taken direct closure, 4 patients were taken pectoralis major musculocutaneous flap, and one patient was taken esophageal transfer. The other 14 patients were taken 11 pectoralis major musculocutaneous flaps and 3 free flaps without pharyngostoma formation. Conclusion: Fistula is a troublesome complication resulting after resection of head and neck cancer. Early detection and adequate treatment according to the period and condition of the fistula may prevent further complications and reduce the pain of the patient.