• 한국방재학회:학술대회논문집
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• 2011.02a
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• pp.178-178
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• 2011

도로소음은 다양한 소음원에 의해 발생하며, 도로를 이용하는 사람과 도로 주변사람에게 큰 불편을 초래한다. 보다 쾌적한 환경을 원하는 현대인에게 있어 도로 소음의 경감은 중요한 환경 공해로 작용한다. 도로 소음을 줄이기 위해서는 여러 가지 방법이 있을 수 있으며, 이 중 도로 포장의 개선을 통해 도로 소음을 경감할 수 있으며, 이와 같은 포장을 저소음 포장이라고 한다. 저소음 포장은 주행하는 차량의 타이어와 노면이 마찰하면서 발생하는 소음을 최소화하기 위한 것으로 소음 발생의 메커니즘을 바탕으로 하고 있다. 저소음 포장중 가장 널리 사용되고 있는 방법은 공극을 늘리는 것이다. 약 20%의 공극은 타이어와 노면 사이의 에어펌핑음을 최소화 하며, 소리를 흡수하는 역할로 약 3dB의 소음 가소 효과가 있는 것으로 알려져 있다. 소음을 감소시키는 또 하나의 방법은 노면의 표면 조직을 매끈하게 하여 타이어와 노면의 충격음을 줄이는 방법이다. 노면의 평탄성을 개선하기 위해 포장에 사용되는 골재의 최대크기를 줄이는 소입경 포장을 소음 가소의 목적으로 유럽 등지에서 많이 사용되고 있다. 본 연구에서는 이와 같은 저소음 기능을 위해 공극률을 크게 하고 소입경 골재를 사용하는 소입경 저소음 포장의 현장 적용을 위한 배합 설계를 수행하였다. 소입경 저소음 포장의 최대 골재 크기는 현장 적용성과 경제성을 고려하여 10mm 골재를 사용하였으며, 수도권에서 입수한 4곳의 산지 골재를 분석하여 골재 합성 입도를 산정하였다. 10mm 저소음 포장의 골재 입도 범위는 공극률 15~18%를 목표로 하며, 이를 만족하기 위하여 배합 설계를 수행한 결과 5mm 통과 중량 백분율이 약 30%로 하는 개립도가 적당한 것으로 나타났다. 공극이 증가함에 따라 포장의 내구성 향상을 위해 사용된 고점도 바인더는 아스팔트 혼합물의 생산 및 시공온도를 증가시키게 된다. 또한 굵은골재의 비율이 높은 개립도 아스팔트 혼합물의 경우 운반과정과 포설 과정에서 온도가 빨리 떨어지는 단점이 있다. 이를 극복하기 위하여 중온 첨가제의 사용을 통해 생산 및 다짐온도를 낮추고자 하였다. 소입경 저소음 포장의 배합설계 과정은 배수성 포장의 배합설계 과정과 유사하나, 칸타브로 손실률과 흐름실험의 변곡점을 기준으로 할 경우, 칸타브로 손실률과 흐름 손실률이 매우 작아 변곡점을 판단하기 어렵기 때문에 칸타브로 손실률과 흐름 손실률의 기준 만족 여부로 판별하고, 최적 아스팔트 함량은 공극률을 기준으로 산정하는 것이 바람직할 것으로 판단된다. 중온 첨가제를 사용할 경우는 중온 첨가제로 인한 점도의 변화를 감안하여 혼합 및 다짐 온도를 결정하고 배합 설계를 수행하며, 중온 첨가제의 특성과 양에 따라 최적 아스팔트 함량이 변화하게 된다.

• Culinary science and hospitality research
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• v.22 no.7
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• pp.47-57
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• 2016

This study was conducted to verify the relationships among the image of middle-low price chain hotels, service quality, consumption value, and customer emotion by using the AMOS 22.0 statistic package program. Confirmatory factor analysis and structural equation modeling methods employed for identifying the formulated hypothesis model. According to results, first, it is seen that the image of middle-low price chain hotels has positive effect on the service quality. Second, the image of middle-low price chain hotels has positive effect on the consumption value, and the consumption value has positive effect on the service quality. Third, the service quality does not have positive effect on the customer emotion. Last, the image of middle-low price chain hotels has positive effect on the customer emotion. In this study, we attempted to establish the management strategy device of middle-low price chain hotels by analyzing how the image of middle-low price chain hotels affect the service quality, consumption value, and customer emotion. As a result, when it comes to the service quality according to the image of middle-low price chain hotels, the conviction, in other words, the belief of the hotel staffs was the biggest one. In addition, when it comes to the consumption value according to the image of middle-low price chain hotels, the functional value, the kind service of the hotel staffs was seen as the highest satisfaction. More practical and theoretical implications for developing marketing strategy in context of middle-low price chain hotels has been suggested in conclusions.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.48 no.1
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• pp.16-24
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• 2011

The sound speed of seawater can be calculated by the empirical formula as a function of temperature, salinity and pressure. It is little affected by salinity because the average salinity is 34 psu and varies within a few psu seasonally and spatially in the ocean. Recently, low-salinity water of 24 psu flows into the western sea area of Jeju Island due to the flood of the Yangtze River in China during summer, affecting sound speed profile. In this paper, it was analyzed how environmental changes affected to the underwater communication - the sound speed of low-salinity water was calculated, and the communication channel was estimated by the simulated acoustic rays while the transmitting and receiving depth and the range were varied with and without the low-salinity layer. And The BER (Bit error rate) was calculated by BPSK(Binary phase shift key) modulation and the effects of the low-salinity water on the BER was investigated. The sound speed profile was changed to have positive slope by the low-salinity layer at the sub-surface up to 20 m of depth, forming acoustic wave propagation channel at the sub-surface resulting in the decrease of most of the BER Consequently, this paper suggests that it is important to consider changes of the ocean environment for correctly analyzing the underwater communication and the detection capability.

• Korean Journal of Construction Engineering and Management
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• v.10 no.6
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• pp.107-116
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• 2009

As the Fundamentals of Construction Business Act was revised in December 2004 and its implementing ordinances and enforcement regulations were adjusted in June 2005, the screening system of low price subcontracting has been an obligation to the public owners, having brought about arguments for and against since it enacted in 1983. The statutes for low price subcontracting have been reinforced from this year; for example, it underlines to submit to a project and builds an information network of subcontracting works. The system's original intention was that prevents shoddy and fraudulent constructions caused by low price subcontracting and precludes disturbances of fair trade by screening that whether it satisfies the conditions or not in advance. But, the criterion for the existing low price subcontracting has several issues having held up a true mirror to the real situation. It is arguable to discharge an important task with the primary purpose. This dissertation have researched the problem with a deposit of subcontract and the low price subcontracting basic rate are being used by the criteria for deciding whether it is a low price subcontracting or not, so showing the plan of reformation based on the findings, it wishes to contribute toward making the most of the system's essential intent.

• Journal of Conservation Science
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• v.28 no.4
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• pp.377-385
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• 2012

Anoxic treatments using argon and nitrogen gas in controlled atmospheres have been used as a alternative to methyl bromide for insect disinfection in museums. Anoxic chamber system was manufactured and installed at The National Folk Museum of Korea for the first time in Korea. The internal capacity of anoxic chamber is 0.5m3 in which is able to use argon, nitrogen and carbon dioxide gas. This system is equipped with oxygen concentration, temperature and ralative humidity control devices and automatically controlled oxygen concentration from 0.01 to 20%, temperature from 10 to $50^{\circ}C$ and relative humidity 30 to 80%. To control the oxygen concentration, anoxic chamber system is adopted semi-dynamic method which supplies mixture of humidified gas and dry gas whenever oxygen concentration in chamber becomes higher than setting value. It has kept regularly oxygen concentration, temperature and relative humidity for 20 days using argon gas. To evaluate the disinfection of cigarette beetle larvae and adults and varied carpet beetle larvae, the anoxic chamber system maintained 0.01% of oxygen concentration, $25^{\circ}C$ in temperature and 50% in relative humidity for 30 days. Cigarette beetle larvae were killed in 7 days and adults in 3~5 days. And varied carpet beetle larvae were killed in 3 days. It reaches the conclusion form the evaluation this anoxic chamber system can be used to develop anoxic treatment as an alternative of methyl bromide for insect disinfection of infested cultural properties in museums.

• Journal of Navigation and Port Research
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• v.44 no.6
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• pp.447-452
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• 2020

Extratropical cyclone in winter season is very important in safe operation of ships because it is a major cause of marine accidents due to its strong power. In this study, we used meteorological data, to analyze extratropical cyclones occurring near the 1st Pacific polar front from December 2019 to February 2020. The analysis results are as follows. During those three months, we recorded 41 extratropical cyclones, 8 of which were remarkably developed. The central pressure of the strongest cyclone was 947hPa. The highest number of cyclones were generated in the East P acific Ocean around J apan (16), followed by the areas around Korea, the East China Sea, and the southern Sea of J apan. The cyclones followed five major tracks with a common northeast pattern. We thus concluded that the optimal route for a ship encountering an extratropical cyclone in the North P acific in winter would be south of the cyclone's center traveling eastbound and north of the center traveling westbound.

• Childhood Kidney Diseases
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• v.3 no.1
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• pp.64-71
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• 1999

Purpose : The protective effects of dietary protein on the progression of renal failure were studied in subtotally nephrectomized rats. Methods : Treatment groups were as follows; 5/6 nephrectomy and a normal protein ($18.5\%$) diet (NP); 5/6 nephrectomy and a low protein ($6\%$) diet (LP): 5/6 nephrectomy, a normal protein diet and converting enzyme inhibitor, enalapril (NPE): 5/6 nephrectomy, a low protein diet and enalapril (LPE). Both diets were isocaloric and had the same phosphorus content. Proteinuria, remnant kidney weight, mesangial matrix expansion score and glomerular volume were assessed at 4, 12 and 16 weeks after renal ablation. Results : LP and NP developed progressive hypertension. Eight weeks after surgery, LPE and NPE controlled hypertension. LP, LPE, and NPE had significantly less proteinuria than NP at 16 weeks (P<0.05). Kidney weight in LP were markedly less enlarged than NP (P<0.05). There was no difference in kidney weight between LPE and NPE. At 12 and 16 weeks the mesangial matrix expansion score was significantly less in LP, LPE, and NPE compared to NP (P<0.05). At 12 and 16 weeks mean glomerular volume was significantly less in LP compared to NP (P<0.05). At 12 and 16 weeks mean glomerular volume in LPE was significantly less compared to NPE. Conclusion : Dietary protein restriction afforded considerable protection from renal injury in the rat remnant kidney model. During the enalapril treatment, there was no additional protective effect of dietary protein restriction against the development of renal lesions.

• Journal of the Korea Institute of Building Construction
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• v.13 no.3
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• pp.218-226
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• 2013

Of construction materials, cement and steel are the representative material that carbon dioxide. to reduce carbon emissions in the use of these materials The purpose of this study is low heat type blended cement, which is manufactured using a amount of cement than ordinary low heat blended cement. Low heat blended cement, mixing ratio of 10%, was investigated hydration properties and adiabatic temperature of concrete. The study in order to activate the reaction mineral admixture, a separate source of CaO and $SO_3$ areneeded. gypsum and lime, it expected amount of cement, low-carbon low-heat blended cement could reduce the hydration heat concrete than currentlyused low heat blended cement.

• Journal of the Microelectronics and Packaging Society
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• v.23 no.2
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• pp.37-42
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• 2016

While datacenter operation cost increases with electricity price rise, many researchers study low-power processor based supercomputers to reduce power consumption of datacenters. Reliability of low-power processors for supercomputers can be of concern since the reliability of many low-power processors are assessed based on mobile use conditions. This paper assessed the reliability of low-power processor packages based on supercomputer use conditions. Temperature cycling was determined as a critical failure cause of low-power processor packages through literature surveys and failure mode, effect and criticality analysis. The package temperature was measured at multiple processor load conditions to examine the relationship between processor load and package temperature. A physics-of-failure reliability model associated with temperature cycling predicted the expected lifetime of low-power processors to be less than 3 years. Recommendations to improve the lifetime of low-power processors were presented based on the experimental results.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.12
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• pp.8957-8965
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• 2015

The degree of difficulty in low-income elderly people who living alone' life satisfaction is increased. The aim of this study is to find factors affecting the low-income elderly people who living alone' life satisfaction by examining the comparative influence of loneliness, family support, social support. For achieving this purpose, this study analyzed data of 300 low-income elderly people who living alone in Gyeonggi province. Findings of the study identified that the factors affecting the life satisfaction were health status, loneliness, family support, social support. Further, family support and social support had a significant influence on the low-income elderly people who living alone' life satisfaction even after controlling the influences of other factors. On the basis of the results, practical suggestions to increase the life satisfaction of low-income elderly people who living alone were discussed.