• Journal of Korean Society on Water Environment
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• v.29 no.1
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• pp.7-18
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• 2013

We compared the structure of fish community and condition of major fish species in Lake Chungpyung and Lake Paldang, which are relatively shallow, meso-eutrophic, cascading dam reservoirs on the North Han River. Two lakes have wide littoral zone in the lakeside providing similarly good habitat for fishes, whereas fishery and water recreational activities such as motorboating, water skiing are allowed in Lake Chungpyung but are prohibited in Lake Paldang. The average lengths of large size fishes in Lake Chungpyung are shorter than those of same species in Lake Paldang, resulting in the slight distortion of generation distribution of those species in Lake Chungpyung, possibly owing to the active fishery such as fixed shore net fishing, gill net fishing and angling. Meanwhile the condition of fishes represented by the length-weight relationship of fish species did not show the significant differences between two lakes and showed normal condition. To evaluate the impact of physical disturbance such as loud noise and turbulent wave from water recreational activities to fishes precisely, further studies including physiological responses to stress an spawing activity should be needed.

• Journal of Urban Science
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• v.8 no.2
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• pp.29-34
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• 2019

Benzene pollution is becoming increasingly serious, and the treatment technology of benzene has attracted much attention. In this paper, a self-made photocatalytic reactor was used to explore the removal rate of benzene under the ultraviolet light with the wavelength of 253.7nm. The results showed that the degradation rate of benzene decreased from 64.29% to 16.26% when the concentration increased from 43mg/㎥ to 256mg/㎥ under the condition of 28W UV light intensity and 50s residence time. Under the condition of 28W UV light intensity and 103mg/㎥ concentration, the residence time increased from 16.5s to 50s, and the benzene removal rate increased from 13.23% to 42.72%.Under the condition of benzene concentration 103mg/㎥ and residence time of 50s, the removal rate of benzene increased from 29.34% to 52.58% in the process of UV light intensity rising from 28W to 48W.It is concluded that decreasing the concentration and increasing the residence time of gas were beneficial to the removal of benzene and increasing the light intensity can improve the removal rate of benzene.

• Computers and Concrete
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• v.6 no.4
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• pp.281-303
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• 2009

The lack of safety of bridge deck structures causes frequent repair and strengthening of such structures. The repair induces great loss of economy, not only due to direct cost by repair, but also due to stopping the public use of such structures during repair. The major reason for this frequent repair is mainly due to the lack of realistic and accurate assessment system for the bridge decks. The purpose of the present research was to develop a realistic expert system, called Bridge Slab-Expert which can evaluate reasonably the condition as well as the service life of concrete bridge decks, based on the deterioration models that are derived from both the structural and environmental effects. The diagnosis assessment of deck slabs due to structural and environmental effects are developed based on the cracking in concrete, surface distress and structural distress. Fuzzy logic is utilized to handle uncertainties and imprecision involved. Finally, Bridge Slab-Expert is developed for prediction of safety and remaining service life based on the chloride ions penetration and fick's second law. Proposed expert system is based on user-friendly GUI environment. The developed expert system will allow the correct diagnosis of concrete decks, realistic prediction of service life, the determination of confidence level, the description of condition and the proposed action for repair.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 1994.05a
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• pp.11-17
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• 1994

The increase of road traffic niose in residential area has been considered to be a serious environmental problem to deteriorate a living condition. The understanding of noise environment in multiple family housing is needed for noise reduction. This study attempts to find out the characteristics of noise environment. For this purpose, the field survey has been carried out to investigate the noise environment(sound level, quality of sound) and the residents' responses(noiseness, annoyance) for noise environment based on 173 households living in 3 apartment compounds built in Pusan according to site location. The major findings are as follows : 1. The sound levels by road traffic noise were measured by dB(A) and dB(Lin). The sound levels were : 77.0dB(A), 86.6dB(Lin) in D-Apt, 73.3dB(A), 82.6dB(Lin) in K-Apt, and 59.1dB(A), 74.6dB(Lin) in M-Apt. Especially, the difference between dB(A) and dB(Lin) was very big in the cae of M-Apt with a barriers for traffic noise reduction. 2. The internal sound levels were shown the soudn attenuation by horizontal distance and by opening or shuting condition of windows.

• Journal of Korean Society for Atmospheric Environment
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• v.21 no.2
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• pp.227-242
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• 2005

The aim of this study is to relieve the poor ventilation problem of the diesel locomotive engine load test building, located in an urban area. This paper evaluates the ventilation performances of the studied load test building based on the temperature measurement experiment and the computational fluid dynamics (CFD) during the engine load test. The temperature rise caused by the radiator blower of the building was turned out to be the main cause of disturbing the thermal conditions of the building. The indoor temperature distributions simulated by Fluent were validated with the temperature measurement results obtained from the studied building. The simulation results indicated that the comfort condition of this building was poor We suggested several remedial changes in the duct structure of this building for the improvement of the comfort conditions. In addition, a prototype drawing combining several improved design options was proposed. and then the simulation of the temperature distribution in the proposed prototype was performed. The result indicated that the indoor thermal condition of this proposed building was improved when compared with that of the current building.

• Journal of Korean Society on Water Environment
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• v.28 no.3
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• pp.426-435
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• 2012

The variation of stream flow is the one of the most important factors which influence on that of water quality in the unit watershed. The target water quality goal is established and permissible load is allotted in the base of the standard flow condition along with its water quality for the management of Total Maximum Daily Loads (TMDLs). A standard flow selected could cause problems in the load allotment if it was not properly arranged. This study reviewed the acquisition of water quality data, the self-variation and the retainability in water quality on the specific flow conditions. This study also proposed the median and the adjusted average flow condition out of general flow conditions as alternative standard flow conditions. It is considered that the alternatives can make the water quality data easily acquired and the water quality representativeness more enhanced on the standard flow conditions.

• Nuclear Engineering and Technology
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• v.32 no.3
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• pp.274-282
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• 2000

The simulation of water balance was conducted for suggested four alternative multi-layer cover design of near-surface radioactive waste disposal facility under domestic climate condition. The analysis was also conducted for the most favorable one out of four alternative cover design under conservative scenarios. Until 100 years after closure of disposal vault, the infiltration flux for the most favorable cover design was negligible even under doubling of the ambient precipitation condition. When the degradation of asphalt and geomembrane after 100 years of closure was considered, the infiltration flux significantly increased almost to the design criteria of cover system in I' Aube disposal facility. And it was found that the hydraulic conductivity of bentonite/sand as a bottom barrier should be no greater than 1$\times$10$^{-7}$ cm/sec recommended by U.S. EPA.

• Journal of Korean Society on Water Environment
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• v.22 no.1
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• pp.17-22
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• 2006

This study is about backwash condition and membrane fouling at continuous coagulation/ultrafiltration process in water treatment. The capacity of pilot plant was $0.06m^3/d$. The result of the test, Backwash cycle time and duration time had a significant effect on the efficiency of system and backwash. Backwash duration time was determined to be fixed in 30 seconds for the system with more than 95% recovery rate, It needed 30 minute backwash frequency. During the continuous operation, membrane fouling was analyzed by determining the filtration resistance ($R_i$) and cake layer resistance ($R_c$). At the initial stage, filtration resistance highly influenced the fouling behavior. But after 1.5 hours, cake layer resistance became more important than filtration resistant.

• Journal of the Society of Naval Architects of Korea
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• v.42 no.6 s.144
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• pp.679-685
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• 2005

Until now, the stealth design to reduce the infrared signature of ship haven't been carried out using the proper design criteria. The study on the maritime meteorological environment in the Korean seas hasn't been accomplished yet, so the design criteria of the maritime meteorological environment was just given by the engineering sense without experience of the Navy and/or of the shipyard. Even in rather good conditions(summer condition), the estimated IR signature of a ship showed larger values and couldn't predict the worst condition during the operation of a ship at sea. In this study, domestic maritime meteorological data were collected and variables affecting the IR signature of a ship had been derived through the sensitivity study of IR signature according to the maritime meteorological environment in Korean seas. The basic study on the criteria of the stealth design of IR signature has been carried out.

• Culinary science and hospitality research
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• v.12 no.4 s.31
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• pp.63-79
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• 2006

This study was conducted to investigate the effect of restaurant environment upon customers' satisfaction and crowdedness awareness from July 4 to 30. Total 800 sets of questionnaire were distributed among major foodservice corporations including 16 restaurants from McDonald, Burger King, Popeyes, KFC, Ritz Carlton, Intercontinental, The Westin Chosun, Hilton, Merriot, Outback Steak House, Bennigans, VIPS, Pizza Hut, Pul-hyanggi(Scent of grass), Nolboo Co., and Our Story. They received 50 sets each to hand out to their customers. Out of total 800 sets of questionnaires, 592 sets (74.25%) were retrieved and underwent the Multiple Regression Analysis. We found the following results from the study. First, among each variable of restaurant environment that had a significant effect on crowdedness, "fast service" and "responsiveness to customer complaints" scored a regression coefficient value 0.381 and 0.325 respectively. Second, among each restaurant environment factor that had a significant effect on crowdedness, "quality of facilities" scored the highest regression coefficient value 0.423 with a standard error score 0.1074, followed by "condition of waiting", "overall ambience" and "service quality" in ascending order. Third, in the analysis of the effect of each environmental factor upon the satisfaction rate, "condition of waiting" showed the highest regression coefficient value 0.3821 with a standard error score 0.4565, followed by "cleanliness", "service quality" and "convenience', in ascending order.