• Title/Summary/Keyword: Life Time value

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The Characteristics of Probable Maximum Flood on Wi Stream Watersheds (위천유역(渭川流域)의 가능최대홍수량(可能最大洪水量) 특성(特性))

  • Choi, Kyung-Sook;Suh, Seung-Duk
    • Current Research on Agriculture and Life Sciences
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    • v.16
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    • pp.37-44
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    • 1998
  • The estimation of PMP (Probable Maximum Precipitation) and the analysis of characteristics of PMF (Probable Maximum Flood) according to the types of time distribution of rainfall and variations of base flow for the determination of design flood of major hydraulic structures in the watershed area of Wi stream were analysed. The PMP was estimated by the hydro-meteorological method suggested by the guideline of the World Meteorological Organization(WMO). The Blocking method was cited to transpose from PMP to PMS (Probable Maximum Storm) with time distribution. The unit hydrograph, applied for the estimation of PMF was derived by Clark's method. The summaryzed results : (1) The 72 hrs duration PMP in the area is 477.3mm which is 80mm less than the PMP map in Korea and 134 mm lager than the maximum precipitation of 342.9mm in Taegu, near the Wi stream watershed. (2) According to the types of time distribution and variations of base flow, the ranges of PMF for advanced type, central type and delayed type are 3,145.3~3,348.3cms, 3,774.6~3,977.7cms and 3,814.6~4,017.3cms, respectively. Those mean that peak discharge of advanced type is 600cms less than the central type and delayed type. (3) Delayed type among three types by Blocking method has been estimated the largest PMF of 4,017.3cms, and the advanced type has been estimated the smallest PMF of 3,145.3cms. The mean value of the peak PMF of 3,653.6cms may probably be resonable PMF in the Wi stream watershed. The mean PMF could probably be 1.7 times lager than the result of Gajiyama's equation. It is equivalent to the flood of return period 1,000 to 10,000 yrs.

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Experimental Study on Autoignition of Superabsorbent Polymers (고흡수성 중합물질의 자연발화에 대한 실험적 연구)

  • Jong-Man Heo;Jae-Wook Choi
    • Journal of the Society of Disaster Information
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    • v.19 no.2
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    • pp.280-291
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    • 2023
  • Purpose: As fire accidents happen at the production and storage sites of superabsorbent polymers for convenience of daily life, an experimental study was conducted to secure basic data to establish practical preventive measures against them. Method: The sample container (20cm width × 20cm length) was made into a rectangular cuboid with the heights of 3cm, 5cm, 7cm, and 14cm, respectively, to allow access to the infinite flat plane. The front and back of the container were covered with a 300-mesh stainless steel mesh for one-dimensional heat transfer. The sample container was placed in the center of the thermostatic bath, which was heated to a predetermined temperature by setting the thermostat program in advance, and it was determined to be 'ignited' when the central temperature of the sample rose by more than 20℃ above the set temperature, and "unignited" when it was maintained at an approximate value of the set temperature. Result: The critical autoignition temperature was calculated to be 217.5℃ when the height of the sample container was 3 cm, 212.5℃ when it was 5 cm, 202.5℃ when it was 7cm, and 187.5℃ when it was 14cm. The ignition induction time to reach the maximum temperature was 34hours for 3cm, 76hours for 5cm, 143hours for 7cm, and 318hours for 14cm. Conclusion: ① As the size of the container increased, the autoignition temperature decreased and the induction time to reach the maximum temperature increased. ② An apparent activation energy was calculated to be 44.92kcal/mol, with a correlation of 96.93%.

Pharmacokinetic Profiles of Isoniazid and Rifampicin in Korean Tuberculosis Patients (한국인 결핵환자에서 Isoniazid와 Rifampicin의 약동학)

  • Ahn, Seok-Jin;Park, Sang-Joon;Kang, Kyeong-Woo;Suh, Gee-Young;Chung, Man-Pyo;Kim, Ho-Joong;Kwon, O-Jung;Rhee, Chong-H.;Cha, Hee-Soo;Kim, Myoung-Min;Choi, Kyung-Eob
    • Tuberculosis and Respiratory Diseases
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    • v.47 no.4
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    • pp.442-450
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    • 1999
  • Background : Isoniazid(INH) and rifampicin(RFP) are the most effective anti-tuberculosis drugs which make the short-course chemotherapy possible. Although prescribed dosages of INH and RFP in Korea are different from those recommended by American Thoracic Society, there has been few study about pharmacokinetic profiles of INH and RFP in Korean patients who receive INH, RFP, ethambutol(EMB) and pyrazinamide(PZA) simultaneously. Methods : Among the patients with active tuberculosis from Dec. 1997 to July 1998, we selected 17 patients. After an overnight fast, patients were given INH 300mg, RFP 450mg, EMB 800mg and PZA 1500mg daily. Blood samples for the measurement of plasma INH(n=15) and RFP(n=17) level were drawn each at 0, 0.5, 1, 1.5, 2, 4, 6, 8 and 12hrs, and urine was also collected. INH and RFP level in the plasma and the urine were measured by high-performance liquid chromatography(HPLC). Pharmacokinetic parameters such as peak serum concentration(Cmax), time to reach to peak serum concentration(Tmax), half-life, elimination rate constant(Ke), total body clearance(CLtot), nonrenal clearance(CLnr), and renal clearance(CLr) were calculated. Results : 1) Pharmacokinetic parameters of INH were as follows: Cmax; $7.63{\pm}3.20{\mu}g/ml$, Tmax; $0.73{\pm}0.22hr$, half-life; $2.12{\pm}0.84hrs$, Ke; $0.83{\pm}0.15hrs^{-1}$, CLtot; $17.54{\pm}8.89L/hr$, CLnr; $14.74{\pm}8.35L/hr$, CLr; $2.79{\pm}1.31L/hr$. 2) Pharmacokinetic parameters of RFP were as follows: Cmax; $8.93{\pm}3.98{\mu}g/ml$, Tmax; $1.76{\pm}1.13hrs$, half-life; $2.27{\pm}0.54hrs$, Ke; $0.32{\pm}0.08hrs^{-1}$, CLtot; $14.63{\pm}6.60L/hr$, CLr; $1.04{\pm}0.55L/hr$, CLnr; $13.59{\pm}6.21L/hr$. 3) While the correlation between body weight and Cmax of INH was not statistically significant (r=-0.514, p value>0.05), Cmax of RFP was significantly affected by body weight of the patients(r=-0.662, p value<0.01). Conclusion : In Korean patients with tuberculosis, 300mg of INH will be sufficient to reach the ideal peak blood level even in the patients over 50kg of body weight However, 450mg of RFP will not be the adequate dose in the patients who weigh over 50~60kg.

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A Novel Analysis Of Amorphous/Crystalline Silicon Heterojunction Solar Cells Using Spectroscopic Ellipsometer (Spectroscopic Ellipsometer를 이용한 a-Si:H/c-Si 이종접합 태양전지 박막 분석)

  • Ji, Kwang-Sun;Eo, Young-Ju;Kim, Bum-Sung;Lee, Heon-Min;Lee, Don-Hee
    • New & Renewable Energy
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    • v.4 no.2
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    • pp.68-73
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    • 2008
  • It is very important that constitution of good hetero-junction interface with a high quality amorphous silicon thin films on very cleaned c-Si wafer for making high efficiency hetero-junction solar cells. For achieving the high efficiency solar cells, the inspection and management of c-Si wafer surface conditions are essential subjects. In this experiment, we analyzed the c-Si wafer surface very sensitively using Spectroscopic Ellipsometer for < ${\varepsilon}2$ > and u-PCD for effective carrier life time, so we accomplished < ${\varepsilon}2$ > value 43.02 at 4.25eV by optimizing the cleaning process which is representative of c-Si wafer surface conditions very well. We carried out that the deposition of high quality hydrogenated silicon amorphous thin films by RF-PECVD systems having high density and low crystallinity which are results of effective medium approximation modeling and fitting using spectroscopic ellipsometer. We reached the cell efficiency 12.67% and 14.30% on flat and textured CZ c-Si wafer each under AM1.5G irradiation, adopting the optimized cleaning and deposition conditions that we made. As a result, we confirmed that spectroscopic ellipsometry is very useful analyzing methode for hetero-junction solar cells which need to very thin and high quality multi layer structure.

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Applying Lean, Green, and Six-Sigma Framework to Improve Exterior Construction Process in Saudi Arabia

  • Banawi, Abdul-Aziz;Bilec, Melissa
    • Journal of Construction Engineering and Project Management
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    • v.4 no.2
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    • pp.12-22
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    • 2014
  • Over the last decade, Saudi Arabia has experienced significant economic increases as evidenced by the 30% growth in its gross domestic product; furthermore, the construction industry has increased 10% in the same time period. Due to this significant growth, the construction industry is encountering issues related to construction quality resulting in significant waste and associated environmental impacts. In this research, we applied our previously developed framework that integrates three different methods-Lean, Green, and Six-sigma - to a residential construction complex in Saudi Arabia. Our aim of this case study was to explore the application of the framework in practice to glean quantitative results and further validate the framework. In the case study, we used the developed framework to identify a significant issue related to quality and delays - final completion of 53 residential units was delayed because of failed exterior buildings surfaces. We then used the framework to define the causes behind the defects via a field investigation of the 53 units. Of the defect, construction execution was responsible for 43% of the defect, 31% untrained workers, 19% unfavorable construction weather condition, with 7% accounting for other issues. A procedure was developed in concert with the construction manager and overall developer reducing the amount of rework and waste causes revealed by the field examination and the framework. Although two steps were added to the original construction process to overcome waste causes, still save a lot of resources and reduces environmental impact. In summary, we found that the Lean, Green, Six-sigma framework increased productivity, quality, and reduced waste.

Developing Design Education Program concerning Sustainable Fashion (지속가능 패션 실용화를 위한 디자인 교육 프로그램 개발)

  • Lee, Youngsun;Choy, Hyonsook
    • Journal of the Korean Society of Costume
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    • v.64 no.2
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    • pp.50-69
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    • 2014
  • Sustainability has been a big issue over the whole global industry lately and is an important fashion trend that reflects the modern phase of the time. The concept of sustainable fashion includes physical fashion products made from eco-friendly or recycle materials as well as ethical value such as corporate social responsibility for environment, labor or working condition. Fashion companies of advanced countries who are aware of the geo-environmental and ethical issues found that generating profits by setting trends and pursuing external beauty can no longer be the ultimate goal of fashion companies, and started to recognize the importance of sustainable fashion as a future-oriented trend. Not only fashion industry but also governments of advanced countries have been playing a leading role to educate the people regarding the importance of sustainable fashion and making large investments to foster industry specialists in educational institution. The aim of this study is to propose sustainable fashion design education program that fits the domestic university curriculum and government-leading education program in order to set the foundation for sustainable fashion industry. Thus, this study investigates successful cases of foreign government-led sustainable fashion education that can be introduced to improve domestic sustainable fashion education. The empirical study of the research is developing 12-15 week university level education program to foster specialists in sustainable fashion. The survey carried out by the students who participated in the program shows the change of perception on sustainable fashion. Developed university level program can be spread to municipal corporation, school of continuing education, and etc. in order to derive participation and problem perception of the citizens on sustainability. Developing systemized sustainable fashion design education program would be the first step of sustainable fashion by educating students who will take the leading role in the future fashion industry. Moreover, it can strongly influence future customer education as well as a special education inducing interest on sustainability in everyday life. A follow-up study is expected to serve as a foundation for sustainable fashion to take root successfully in the fashion industry.

A Study on Performance Warranty Criteria for Expressway Jointed Concrete Pavements (고속국도 줄눈 콘크리트 포장 성능보증 기준 연구)

  • Yeo, Hyun-Dong;Ahn, Deok-Soon;Suh, Young-Chan;Jeong, Jin-Hoon
    • International Journal of Highway Engineering
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    • v.13 no.3
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    • pp.65-73
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    • 2011
  • Recently, researches to introduce the performance warranty contract are in progress for quality improvement of road pavements. The performance warranty contract is a type of contract in which contractors guarantee to maintain certain level of performance during a period from completion of construction. The contract use in Europe and the U.S is being increased because it has been known to contribute to improvement of structure quality, reduction of life cycle cost, development of construction techniques, and etc. The research on performance indicators, threshold values, and warranty durations is essential to effectively introduce the contract in Korea. In this study, literatures on the performance warranty contract for concrete pavements of the Minnesota, Indiana, and Florida of the U.S. were reviewed. Major distresses influencing the pavement performance were investigated and analyzed in the jointed concrete pavement sections of 21 Korean expressway routes to be compared to the performance indicators, threshold values, and warranty durations of the states. More accurate comparison is expected by investigation in planned sections for a long time.

Detecting Inner Attackers and Colluded nodes in Wireless Sensor Networks Using Hop-depth algorithm (Hop-depth 알고리즘을 이용한 무선 센서 네트워크상에서의 내부공격자 및 공모노드 검출)

  • Rhee, Kang-Hyeon
    • Journal of the Institute of Electronics Engineers of Korea CI
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    • v.44 no.1
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    • pp.113-121
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    • 2007
  • Commonly, in the Sensor Network that composed with multiple nodes uses Ad-hoc protocol to communicate each other. Each sensed data packets are collected by base node and processed by Host PC. But the Ad-hoc protocol is too vulnerable to Sinkhole attack, where the intruder attracts surrounding nodes with unfaithful routing information, and then performs selective forwarding or changes the data passing through it. The Sinkhole attack increases overhead over the network and boosts energy consumption speed to decrease network's life time. Since the other attacks can be easily adopted through sinkhole attack, the countermeasure must be considered carefully. In this paper, we proposed the Hop-depth algorithm that detects intruder in Sinkhole attack and colluded nodes. First, the proposed algorithm makes list of suspected nodes and identifies the real intruder in the suspected node list through the Hop-depth count value. And recalculates colluder's path information to find the real intruder. We evaluated the performance of the proposed algorithm using NS2. We compared and analyzed the success ratio of finding real intruder, false positive ratio, false negative ratio, and energy consumption.

Evaluation on the Reliability Attributes of Finite Failure NHPP Software Reliability Model Based on Pareto and Erlang Lifetime Distribution (파레토 및 어랑 수명분포에 근거한 유한고장 NHPP 소프트웨어 신뢰성모형의 신뢰도 속성에 관한 평가)

  • Min, Kyung-il
    • Journal of Industrial Convergence
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    • v.18 no.3
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    • pp.19-25
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    • 2020
  • In the software development process, software reliability evaluation is a very important issue. In particular, finding the optimal development model that satisfies high reliability is the more important task for software developers. For this, in this study, Pareto and Erlang life distributions were applied to the finite failure NHPP model to evaluate the reliability attributes. For this purpose, parametric estimation is applied to the maximum likelihood estimation method, and nonlinear equations are calculated using the bisection method. As a result, the Erlang model showed better performance than the Pareto model in the evaluation of the strength function and the mean value function. Also, as a result of inputting future mission time and evaluating reliability, the Erlang model showed an effectively high trend together with the Pareto model, while the Goel-Okumoto basic model showed a decreasing trend. In conclusion, the Erlang model is the best model among the proposed models. Through this study, it is expected that software developers will be able to use it as a basic guideline for exploring and evaluating the optimal software reliability model.

A Study on The Grotesque Make-up in the Late 1990′s - Focused on Make-up Advertisements and Collections - (1990년대 후반 그로테스크 메이크업에 관한 연구 - 메이크업 광고와 컬렉션을 중심으로 -)

  • 장미숙;양숙희
    • The Research Journal of the Costume Culture
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    • v.8 no.3
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    • pp.436-499
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    • 2000
  • The purpose of this study is to be inquired social and cultural significance of the Grotesque phenomenon in the late 1990's make-up, as well as its experimentalism and avantgardism. The Grotesque is the aesthetic concept, which is composed of ambivalent structure of humor and horror, interest and disgust through join of heterogenous factors, distortion, extreme and overstatement in the patterns and materials of make-up. The Grotesque in the modern make-up is represented in the make-up advertisements and collections. In this paper, the author classified the Grotesque phenomenon with the Kitsch, the Machine, the Animal and the Devil, focused on heterogenous factors. The results are as follows. 1. The Kitsch in the make-up uses not cosmetics but imitations, ready-made goods, and ordinary materials. It expresses modern culture's laziness through shocking self-expression. 2. The Machine in the make-up means silver or white color's make-up, and represents cyber period's arrival through contrary irony, loss of the human value and the personifications of machine. At the same time, it is understood as the curing of human alinetion. 3. The Animal in the make-up utilizes the wild animal's horn, the reptiles'sputum, and the legend's animal. It points out a human false virtual image, and overturns make-up's traditional aesthetic concept. 4. The Devil in the make-up shows vampire's cuspid, demon's horn, artificial nail, and black color's make-up. It raises social irrationality and discrepancy of capitalism, and expresses paradoxically the nature of human life. The Devil in the make-up expresses the creator's innovation, anxiety of fin-de-siecle, and simultaneously criticizes and cures confused reality. It shows also avantgarde implementation of dissolution of traditional aesthetic concept and acceptance ugliness.

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