• Fire Science and Engineering
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• v.15 no.1
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• pp.1-6
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• 2001

In this study, reduced-scale experiments were conducted to understand smoke movements in tunnel fires with the natural ventilation. The 1/20 scale experiments were conducted under the Froude scaling since the smoke movement in tunnels is governed by buoyancy force. Three cases of experiments, in which a natural vent location varied from 1 m, 2 m and 3 m from the fire source symmetrically, were conducted in order to evaluate the effect of the position of ventilation systems on smoke movement. In case of a poo1 whose diameter is 4.36 cm, the temperature of smoke layer passed through the vent was maintained 7~$8^{\circ}c$ less than that of smoke layer without a vent. In case of a pool whose diameter is 5.23 cm, the average velocity passed through the vent was decreased when it was close to the fire source. And the maximum delay time was 3.86s. In CASE 1, the ceiling temperature was decreased by approximately 8$^{\circ}C$ and the vertical temperature was decreased by approximately $7^{\circ}c$. In CASE 2, both ceiling and vertical temperature wert decreased by $3^{\circ}c$ and in CASE 3, they were decreased by $2^{\circ}c$ each. It was confirmed that the thickness of smoke layer was maintained uniformly under the 25% height of tunnel through the visualized smoke flow by a laser sheet and the digital camcoder.

• Economic and Environmental Geology
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• v.40 no.1 s.182
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• pp.129-140
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• 2007

CFC(CFC-12, CFC-11 and CFC-113) analytical system for air and water was constructed using a customized purge and trap extraction device and a gas chromatograph with an electron capture detector. Sampling methods of air and water for CFCs were also established. The analytical system was experimentally optimized to result in reproducibilities of triplicates less than 2% for current air samples and less than 5% for groundwater samples with CFC-12 concentration of 160 to 180 pg/kg, and verified with respect to the CFC system in USGS, which showed analytical results were in agreement within 10%. CFCs in air were monitored at three sites over 19-month period in the central part of South Korea, and the result indicates no significant local sources of CFCs in those areas. For groundwater in Jeju Island, CFCs were measured over a year with a two-month interval. The time-series data showed seasonal fluctuations which could be interpreted by the effect of recharge pulse derived from large amount of rainfall during monsoon period with a few month delay, which indicates high permeability of basaltic rocks in Jeju Island.

• 한국환경농학회:학술대회논문집
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• 2009.07a
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• pp.329-338
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• 2009

Emission of ammonia to the atmosphere are considered a threat to the environment. The application of livestock manure and compost contributes significantly to the emission of ammonia from agriculture. The reduction in NH3 losses from field-applied manure and compost would be a good strategy to reduce national $NH_3$ emission. In this study, various application techniques of liquid manure and compost were compared to evaluate their potential for reducing $NH_3$ emission. In compost application, the reductions in $NH_3$ emission were 70 and 15% for immediately rotary after application (IRA) and rotary at 3-day after application (RA-3d) in comparison with surface application (SA). Total ammonia emissions for 13 days, expressed as % ammonia-N applied in compost, were 42, 35.7, and 12.7% for SA, RA-3d, and IRA treatments, respectively. Mean reductions in NH3 emission from application of liquid pig manure were 26 and 50% for rotary harrow after surface broadcast application in spring and fall, respectively, in comparison with surface broadcast application. Ammonia emission rate was decreased with increasing water content in soil due to dilution effect, but this reduction only was temporary up to 12 hours after application and cumulative $NH_3$ emission was increased with increasing water content in soil. However, the delay would be beneficial because it allows time for rotary hallow of the applied liquid pig manure. Therefor, ammonia emission can be reduced by immediately incorporation of liquid manure and compost after surface application.

• Journal of Korean Society of Transportation
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• v.22 no.7 s.78
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• pp.131-137
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• 2004

Conventional traffic signal optimization models assume that green intervals for pedestrian crossings are given as exogenous inputs such as minimum green intervals for straight-ahead movements. As the result, in reality, the green intervals of traffic movements may not distribute adequately by the volume/saturation-flow of them. In this paper, we proposed signal optimization models formulated in BMILP to integrate pedestrian crossings into traffic movements under under-saturated traffic flow. The model simultaneously optimizes traffic and pedestrian movements to minimize weighted queues of primary queues during red interval and secondary queues during queue clearance time. A set of linear objective function and constraints set up to ensure the conditions with respect to pedestrian and traffic maneuvers. Numerical examples are given by pedestrian green intervals and the number of pedestrian crossings located at an arm. Optimization results illustrated that pedestrian green intervals using proposed models are greater than those using TRANSYT-7F, but opposite in the ratios of pedestrian green intervals to the cycle lengths. The simulation results show that proposed models are superior to TRANSYT-7F in reducing delay, where the longer the pedestrian green interval the greater the effect.

• Journal of Korean Society on Water Environment
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• v.31 no.1
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• pp.12-18
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• 2015

In this research, the hydrologic effects between a pre-existing urban landuse and low impact development (LID) applied conditions were compared and evaluated. The infiltration trench and tree box filter that were utilized in LID represent only 1% of the catchment area that they drain. Storm event monitoring were conducted from July 2010 to July 2014 on a total of 22 storm events in both LID sites. After LID, hydrological improvement was observed as the sites exhibited a delay (lag time) or reduction in the magnitude, frequency and duration of runoff and flow peaks as the rainfall progress. In addition, the maximum irreducible peak flow reduction for infiltration trench was found to be 61% and 33% for the tree box filter when rainfall was 40 mm and 30 mm, respectively. In designing LID, it is recommended to consider the storage capacity and catchment area, as well as the amount of rainfall and runoff on the site.

• Journal of Sericultural and Entomological Science
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• v.41 no.1
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• pp.9-13
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• 1999

The experiment was carried out to investigate the absorption profile of blood glucose in mice administered to silkworm powder MeOH extract. The mice was injected to oral load of maltose, sucrose and lactose(2 g/kg) and silkworm powder MeOH extract at the same time. After injecting the sample, blood glucose concentration was measured at 0, 30, 60, 120, 180 and 240 minutes. Blood glucose lowering effect of silkworm powder for loading maltose was 69% in postprandial 30 minutes. After the postprandial 60 minutes, the glucose was absorbed slowly. Total amount of blood glucose absorption in mice administered to maltose were 560.7 mg/dl during 240 minutes. That of silkworm powder MeOH extract marked 534.7 mg/dl. Total amount of blood glucose from oral loading sucrose reached to 508.9 mg/dl. That of loading silkworm powder MeOH extract were 468.8. But, silkworm powder was not inhibited lactose absorption. As a above results, silkworm powder inhibits the transient rising of blood glucose after postprandial 30 minuts through inhibition of ${\alpha}$-glucosidases. In case of starvation silkworm powder don't promote the hypoglycemia. In addition, silkworm powder induces the delay absorption of glucose without loss of it.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.2
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• pp.237-242
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• 2001

Colostrum deprived, newborn pigs (N=12, $1.64{\pm}0.05kg$) were used to study the renal threshold of carnitine, and effects of emulsified medium-chain triglyceride (MCT, tri-8:0) feeding on kinetics of plasma carnitine and urinary carnitine excretion. An arterial catheter was inserted through an umbilical artery, and a bladder catheter was inserted via the urachus. Piglets were oro-gastrically gavaged with one of six carnitine levels (0, 60, 120, 180, 240, $480{\mu}mol/kg\;W^{0.75}$) with (+MCT) or without medium-chain triglycerides (-MCT) in 0.9% NaCl solution. Blood was sampled into heparinized tubes at 0, 1, 2, 4, 6, 8, 14, and 20 h after gavage, and urine was collected and pooled into 1 h or 2 h composite samples to determine free- and short-chain carnitine concentrations. Plasma from the 12 newborn piglets before gavage contained $10.6{\pm}1.2{\mu}mol/L$ free carnitine and $7.2{\pm}0.6{\mu}mol/L$ acid-soluble acyl carnitine. The renal threshold for carnitine was similar between the MCT and the +MCT group (42.6 13.1 and $46.4{\pm}2.0{\mu}mol/L$, respectively), but the correlation between plasma free carnitine and urinary excretion was altered. Plasma free carnitine linearly increased with increasing carnitine dosage (-MCT group, $R^2=0.95$, p<0.001; +MCT group, $R^2=0.91$, p<0.001), but was decreased by 50% when medium-chain triglycerides were fed. The peak in plasma free carnitine concentration was depressed by medium-chain triglycerides feeding also. Therefore, the plasma and urinary short-chain/free carnitine ratio of the +MCT group was increased by 100% and 40%, respectively (p<0.01). Feeding of medium-chain triglycerides may delay plasma carnitine elevation via altering the kinetics of absorption. Similarly, the plasma and urinary short-chain/free carnitine ratio were affected by interaction between medium-chain triglycerides and time (p<0.01). The present study suggests that an oral carnitine dose over $480{\mu}mol/kg\;W^{0.75}$ may be needed to reach the free carnitine renal threshold within a short period, especially when provided together with medium-chain triglyceride.

• The Korean Journal of Nuclear Medicine
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• v.32 no.3
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• pp.276-289
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• 1998

Purpose: To evaluate dysphagia objectively and quantitatively, and to clarify the effect of neck position and viscosity changes in patients with aspiration and laryngeal penetration. Materials and Methods: We studied 35 patients with dysphagia and 21 normal controls using videofluoroscopy and scintigraphy. Videofluoroscopy was performed with barium with three different viscosity, and scintigraphy was done with water, yogurt, and steamed egg mixed with Tc-99m tin colloid. If aspiration was found during videofluoroscopic examination, patient's neck position was changed and study repeated. Videofluoroscopy was analyzed qualitatively. We calculated 7 quantitative parameters from scintigraphy. According to the videofluoroscopic findings, we divided patients into 3 subgroups; aspiration, laryngeal penetration, and no-aspiration group. Results: The result of videofluoroscopy revealed that the most common finding was the delay in triggering pharyngeal swallow. Pharyngeal transit time (PTT) and pharyngeal swallowing efficiency(PSE) in patients with aspiration were signifi-cantly different from other groups. After neck position change, aspiration could be reduced in all of 7 patients, and laryngeal penetration reduced by about 82%. PTT and PSE were also improved after position change. Aspiration and laryngeal penetration occurred more frequently in thin liquid swallowing than in thick liquid and solid swallowing. Conclusion: PTT and PSE were useful for the evaluation of dysphagia. Aspiration and laryngeal penetration could be reduced when appropriate position assumed. We could decrease the chance of aspiration by changing the patient diet consistency. Scintigraphy might be useful tool to quantitate and follow up these changes.

• Journal of Wetlands Research
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• v.19 no.3
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• pp.359-365
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• 2017

Impermeable surfaces such as transportation land uses including roads and parking lots accumulate high heavy metals and particulate matters concentration especially during dry season which worsens the river water quality and distort the water circulation system during rainfall events. Recently, the government has been promoting policies to install Low Impact Development (LID) facilities such as permeable pavements or grass blocks in parking lots or pavements. However, transition of asphalt-paved surfaces to permeable pavement generated asphalt wastes which are detrimental to the environment and has cost implications due to its removal and disposal. Therefore this study was conducted to provide a method of constructing a cost-effective permeable pavement to reduce waste generation and cost. In this study, comparative analysis of the water circulation capacity and economic efficiency of the traditional construction method and new method proposed in this study through the lab-scale experiment. The proposed method was to make holes in existing asphalt pavements, layout geotextile fabric and permeable base media such as sand before compaction. After compaction, layout grass blocks on the compacted base media then layout sand in between each grass blocks before compaction. Apparently, there was no significant difference between the traditional installation method of permeable pavement and the proposed method in this study considering surface runoff, infiltrated volume, stored volume, and rainfall-runoff delay time. The proposed method in this study generated 86% less wastes compared to the traditional installation method and has 70% cost reduction considering asphalt removal and disposal. The construction method proposed in this study yielded similar performance compared to the traditional installation method and water circulation effect, but was proven to be less complicated and economical.

• Journal of Digital Contents Society
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• v.12 no.1
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• pp.85-94
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• 2011

QoS(Quality of Service) is defined as "The collective effect of service performance which determines the degree of satisfaction of a user of the service" by ITU-T Rec. E.800. While the use of VoIP(Voice Over Internet Protocol) has been widely implemented, persistent problems with QoS are a very important sue which needs to be solved. This research is finding the assignment of VoIP QoS to deduct how to manage the control system and presenting the QoS control process and framework under NGN(Next Generation Network) environment. The trial framework is the modeling of the QoS measurement metrics, instrument, equipment, method of measurement, the series of cycle & the methodology about analysis of the result of measurement. This research underlines that the vulnerability of the VoIP protocol in relation to its QoS can be guaranteed when the product quality and management are controlled and measured systematically. Especially it's very important time to maintain the research about VoIP QoS measurement and control because the big conversion of new network technology paradigm is now spreading. In addition, when the proposed method is applied, it can reduce an overall delay and can contribute to improved service quality, in relation to signal, voice processing, filtering more effectively.