• Journal of Environmental Health Sciences
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• v.26 no.3
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• pp.98-102
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• 2000

The aim of this study was to evaluate on the removal effect of total nitrogen in municipal wastewater by decreasing hydraulic retention time(HRT) from 6 hour to 4 hour on CNR process. CNR-A(Cilia Nutrient Removal) is the process combining A2/O process with cilium media of H2L corporation. The removal efficiencies for T-N were 63.1% in A-1 reactor, and 73.5% in A-2 reactor and 77.0% in A-3 reactor. The specific nitrification(g-NH3-N/g-MLVSS.d) of Oxic in CNR-A process was 0.07-0.32. The specific denitrification in Anoxic and the specific nitrification inOxic was higher in HRT 4 hour because of optimum F/M ratio.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2003.10a
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• pp.611-614
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• 2003

A Korean Type Biofilter system combined with a conventional anoxic tank(septic tank) process was investigated in regard to its feasibility for removing organic as well as nutrients from the rural wastewater in Korea. At recirculation, the removal rate in BOD and SS increased slightly as much as 93 and 95% compared with non-recirculation system. On the other hand, removal rates of the total nitrogen(T-N) and total phosphorous(T-P) in recirculation system increased significantly as much as 62 and 57%, respectively compared with non-recirculation system. The recirculation system provides sufficient treatment to improve the removal rate in T-N and T-P.

• Journal of Animal Environmental Science
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• v.6 no.2
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• pp.65-72
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• 2000

This study was conducted to investigate the effects of artificial filaments equipped in the aeration tank of aerobic·fermentation system on the removal efficiency of swine wastes which were fermented an aerobically and thus containing high nitrogen. Two aerobic fermentation system each consist4s of 4 tanks ; storage tank, 1st and 2nd aeration tank and settling tank were run before and one or three weeks after equipment of artificial filament in the aeration tanks. Total solids concentration tended to increase by aerobic fermentation in all running periods. However, decreased(P<0.05) total nitrogen concentration was shown three weeks after the equipment of artificial filament. Ammonia nitrogen concentration also largely decreased(p<0.05) in both running periods of one and three weeks after equipment of artificial filaments. These results suggest that the artificial filaments may improve the removal efficiency of nitrogen in swine wastewater containing high nitrogen during aerobic fermentation.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1993.10a
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• pp.1379-1394
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• 1993

The purpose of this study is to examine the purification efficiency of the septic tank method which has been applied by the most of Korean livestock farms, in terms of anaerobic and aerobic treatment. Except several days in summer, BOD of effluent shows 1,500 -3,000 ppm by anaerobic process. In most cases , it exceeds according to the seasons show an increase by decrease of temperature. The removal effect on T-N is hardly found. The suspended solids contents of effluent are reduced to the level of 50-90%. Although BOD contents of effluent are kept high in the beginning, the removal rate of BOD shows 80 percent in the latter half by the aerobic treatment . The removal efficiency of total nitrogen does not appear through the experimental period, but the contents of T-N are not increased in the aerobic process unlike in the anaerobic process. The total phosphorous contents in effluent keep a constant level of 14 mg/L in average. The removal rate of phosphorous shows 91 percent i the last stage.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.49 no.3
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• pp.243-250
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• 2004

Two cultivars which are glutinous (Hawcheongchalbyeo) and non-glutinous (Hawcheongbyeo) near isogenic line of rice, were used for this study. The objective of this experiment was to gain the basic information for increasing grain yield of waxy rice by means of source and sink size control. In both Hwacheongbyeo and Hawcheongchalbyeo, the trend of decrease in total and average spikelet weight was ranked as follows; removal of penultimate leaf＜ removal of flag leaf＜ removal of flag leaf and 3ya leaf from the top ＜ removal of flag leaf and penultimate leaf ＜ removal of flag leaf, penultimate leaf, and 3rd leaf from the top. The reduction yale of total and average spikelet weight per panicle of Hwacheongbyeo was higher than those of Hwacheongchalbyeo according to the removal of flag leaf, penultimate leaf, and 3rd leaf from the top. In both cultivars, high-density grain ratio and grain filling ratio of the primary branches were higher Hun those of the secondary branches by leaf clipping treatment. The spikelet number and total spikelet weight per pinicle in both Hwacheongbyeo and Hwacheongchalbyeo were decreased by removal of spikelets on branches compared with control, whereas average spikelet weight and grain filling ratio were increased. The increase rate of average spikelet weight of Hwacheongchalbyeo was much higher than that of Hwacheongbyeo by sink size control. High-density grain ratio by removal of spikelets on branches was higher in Hwacheongchalbyeo, but filled grain ratio was higher in Hwacheongbyeo.

• Journal of the Korea Society of Computer and Information
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• v.22 no.10
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• pp.101-107
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• 2017

In this paper, we study the problem of parallel machine scheduling considering the moving time of multiple servers. The parallel machine scheduling is to assign jobs to parallel machines so that the total completion time(makespan) is minimized. Each job has a setup phase, a processing phase and a removal phase. A processing phase is performed by a parallel machine alone while a setup phase and a removal phase are performed by both a server and a parallel machine simultaneously. A server is needed to move to a parallel machine for a setup phase and a removal phase. But previous researches have been done under the assumption that the server moving time is zero. In this study we have proposed an efficient algorithm for the problem of parallel machine scheduling considering multiple server moving time. We also have investigated experimentally how the number of servers and the server moving time affect the total completion time.

• Journal of Korean Neurosurgical Society
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• v.30 no.sup2
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• pp.348-351
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• 2001

Hemangioblastoma is a benign tumor of vascular origin that develops usually in the posterior cranial fossa. We report a case of supratentorial leptomeningeal hemangioblastoma occurring in a 45-year-old man who received total removal of recurrent cerebellar hemangioblastoma four years ago. He was admitted for the evaluation of severe headache and magnetic resonance image showed a well-enhanced, extra-axial mass in the right parietal region. A presumptive diagnosis was meningioma. It was completely removed with the attached dura. Histological examination including immunohistochemical study showed typical findings of hemangioblastoma. It is emphasized that close observation may be necessary for hemangioblastoma, even after total removal.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.6 no.6
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• pp.49-55
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• 2003

Total phosphorous removal rate was examined of a subsurface-flow treatment wetland system which was constructed on floodplain in the down reach of the Kwangju Stream in Korea from May to June 2001. Its dimensions were 29 meter in length, 9 meter in width and 0.65 meter in depth. A bottom layer of 45 cm in depth was filled with crushed granite with about 15~30 mm in diameter and a middle layer of 10 cm in depth had pea pebbles with about 10 mm in diameter. An upper layer of 5 cm in depth contained course sand. Reeds(Phragmites australis) were transplanted on the surface of the system. They were dug out of natural wetlands and stems were cut at about 40 cm height from their bottom ends. Water of the Kwangju Stream flowed from a submerged dam into it via a pipe by gravity flow and treated effluent was funneled back into the Stream. The number of reed stems increased from 80 stems/$m^2$ in July 2001 to 136 stems/$m^2$ in September 2001. The hight of stems was 44.2 cm in July 2001 and 75.3 cm in September 2001. The establishment of reeds at early operating stage of the system was good. Volume and water quality of inflow and outflow were investigated from July 2001 through December 2001. The average inflow was 40 $m^3$/day and hydraulic detention time was about 1.5 days. The concentration of total phosphorous n influent and effluent was 0.83 and 0.33 mg/L, respectively. The removal rate of total phosphorous averaged about 60%. The removal efficiency was slightly higher, compared with that of subsurface-flow wetlands operating in North America, whose retention rate of total phosphorous was reported to be about 56%. The good abatement rate could be attributed to sedimentation of particle phosphorous in pores of the media and adsorption of phosphorous to the biofilm developed on the surface of them. Increase of standing density of reeds within a few years will develop root zones which may lead to increment in the phosphorous retention rate.

• Environmental Engineering Research
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• v.17 no.1
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• pp.41-46
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• 2012

In this study, the performance of new digestion system (NDS) for the treatment of food waste leachate was evaluated. The food waste leachate was fed intermittently to an anaerobic reactor at increasing steps of 3.3 L/day (hydraulic retention time [HRT] = 30 day), 5 L/day (HRT = 20 day), and finally 10 L/day (HRT = 10 day). In the anaerobic reactor, the pH and alkalinity were maintained at 7.6 to 8.2 and 8,940-14,400 mg/L, respectively. Maximum methane yield determined to be 0.686L $CH_4$/g volatile solids (VS) containing HRT over 20 day. In the digester, 102,328 mg chemical oxygen demand (COD)/L was removed to produce 350 L/day (70% of the total) of biogas, but in the digested sludge reduction (DSR) unit, only 3,471 mg COD/L was removed with a biogas production of 158 L/day. Without adding any chemicals, 25% of total nitrogen (TN) and 31% of total phosphorus (TP) were removed after the DSR, while only 48% of TN and 32% of TP were removed in the nitrogen, phosphorus, and heavy metals (NPHM) removal unit. Total removal of TN was 73% and total removal of TP was 63%.

• Proceedings of the Korean Environmental Health Society Conference
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• 2003.06a
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• pp.144-146
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• 2003

The removal effect of total nitrogen in municipal wastewater by decreasing hydraulic retention time(HRT) from 6 hour to 4 hour on MNR process was not decreased.. The removal efficiencies of nutrient removal process combining A2/O process with media for T-N were 63.1% in the reactor operated 6 hour, and 73.5% in the reactor operated 5 hour and 77.0% in the reactor operated 4 hour.