• Title/Summary/Keyword: Risk function

Search Result 1,706, Processing Time 0.027 seconds

The Hmong Response to State Intervention in Vietnam's Upland: A case study of a remote hamlet in North Central Vietnam (베트남 산악지역에서의 국가의 간섭과 흐몽족의 대응 - 베트남 북중부의 프론티어 마을을 사례로 -)

  • Le, Quy Ngoc Phuong;Kim, Doo-Chul
    • Journal of the Economic Geographical Society of Korea
    • /
    • v.21 no.2
    • /
    • pp.119-138
    • /
    • 2018
  • The Hmong people are one of the largest ethnic groups in Vietnam. They traditionally practice shifting cultivation for their daily subsistence. This group has a traditional governance system as well as strong clan and kinship relationships that occupy an important role in maintaining Hmong culture and livelihoods. The state's approval of the legitimate and statutory law for the Nature Reserve largely excluded local rights of access to and the use of natural resources. This study focusses on Hmong responses to the state interventions of the establishment of the Nature Reserve as well as forest land allocation. Based on Scott's contribution of Moral Economy (1976), the authors argue that local responses function as a 'risk-averter' against state intervention. Meanwhile, the intra and inter-ethnic relationships based on the 'subsistence ethic' help locals successfully mitigate state intervention. These findings help the state rethink their interventions, which have been constructed with very little respect for local differences or the desires of ethnic peoples. Furthermore, the main findings, which reveal that not only the intra-ethnic relationship but also the inter-ethnic relationship among ethnic minorities can play an important role in maintaining the Moral Economy, are expected to deepen the previous understanding on the Moral Economy, which has previously constrained its scope to the intra-ethnic relationship.

A Study on the Development of the Seismic Fragility Functions of the High Speed Railway Tunnels in use (기존 고속철도 터널의 지진취약도 함수 개발에 관한 연구)

  • Kim, Hongkyoon;Shin, Chulsik;Lee, Taehyung;Lee, Jonggun;Park, Duhee
    • Journal of the Korean GEO-environmental Society
    • /
    • v.15 no.11
    • /
    • pp.67-75
    • /
    • 2014
  • In this study, the staged seismic performance evaluations were conducted to the 91 high speed railway tunnels in use for checking whether to comply with the recent design criteria or not. In addition, the seismic fragility functions of the tunnels were developed to allow the probabilistic risk assessment. The results of the staged seismic performance evaluations which consist of a preliminary assessment and a detailed assessment, show that the tunnels comply with the recent design criteria. With reference to the results of previous studies, a form of the proposed seismic fragility functions was set as a log-normal distribution by PGA, and the parameters of the functions were determined by using the probability of damage for the design PGA level. The seismic fragility functions were developed for each types (Cut & Cover, NATM) of tunnels. The seismic fragility functions from this study and the existing research results (FEMA, 2004) were compared to evaluate the seismic performance level of the tunnels, as a result the tunnels of this study were relatively superior to the ASSM tunnels on the seismic performance.

An early warning and decision support system to reduce weather and climate risks in agricultural production

  • Nakagawa, Hiroshi;Ohno, Hiroyuki;Yoshida, Hiroe;Fushimi, Erina;Sasaki, Kaori;Maruyama, Atsushi;Nakano, Satoshi
    • Proceedings of the Korean Society of Crop Science Conference
    • /
    • 2017.06a
    • /
    • pp.303-303
    • /
    • 2017
  • Japanese agriculture has faced to several threats: aging and decrease of farmer population, global competition, and the risk of climate change as well as harsh and variable weather. On the other hands, the number of large scale farms is increasing, because farm lands have been being aggregated to fewer numbers of farms. Cost cutting, development of efficient ways to manage complicatedly scattered farm lands, maintaining yield and quality under variable weather conditions, are required to adapt to changing environments. Information and communications technology (ICT) would contribute to solve such problems and to create innovative technologies. Thus we have been developing an early warning and decision support system to reduce weather and climate risks for rice, wheat and soybean production in Japan. The concept and prototype of the system will be shown. The system consists of a weather data system (Agro-Meteorological Grid Square Data System, AMGSDS), decision support contents where information is automatically created by crop models and delivers information to users via internet. AMGSDS combines JMA's Automated Meteorological Data Acquisition System (AMeDAS) data, numerical weather forecast data and normal values, for all of Japan with about 1km Grid Square throughout years. Our climate-smart system provides information on the prediction of crop phenology, created with weather forecast data and crop phenology models, as an important function. The system also makes recommendations for crop management, such as nitrogen-topdressing, suitable harvest time, water control, pesticide spray. We are also developing methods to perform risk analysis on weather-related damage to crop production. For example, we have developed an algorism to determine the best transplanting date in rice under a given environment, using the results of multi-year simulation, in order to answer the question "when is the best transplanting date to minimize yield loss, to avoid low temperature damage and to avoid high temperature damage?".

  • PDF

Joint Angles Analysis of Intelligent upper limb and lower extremities Wheelchair Robot System (지능형 상 · 하지 재활 휠체어 로봇 시스템의 관절각도 분석)

  • Song, Byoung-Ho;Kim, Kwang Jin;Lee, Chang Sun;Lim, Chang Gyoon
    • Journal of Internet Computing and Services
    • /
    • v.14 no.6
    • /
    • pp.33-39
    • /
    • 2013
  • When the eldery with limited mobility and disabled use a wheelchairs to move, it can cause decreased exercise ability like decline muscular strength in upper limb and lower extremities. The disabled people suffers with spinal cord injuries or post stroke hemiplegia are easily exposed to secondary problems due to limited mobility. In this paper, We designed intelligent wheelchair robot system for upper limb and lower extremities exercise/rehabilitation considering the characteristics of these severely disabled person. The system consists of an electric wheelchair, biometrics module for Identification characteristics of users, upper limb and lower extremities rehabilitation. In this paper, describes the design and configurations and of developed robot. Also, In order to verify the system function, conduct performance evaluation targeting non-disabled about risk context analysis with biomedical signal change and upper limb and lower extremities rehabilitation over wheelchair robot move. Consequently, it indicate sufficient tracking performance for rehabilitation as at about 86.7% average accuracy for risk context analysis and upper limb angle of 2.5 and lower extremities angle of 2.3 degrees maximum error range of joint angle.

Comparison of Safety Level between Driver's Ages by Threshold Zone Luminance Level of Vehicular Traffic Tunnel (터널 경계부 휘도수준에 따른 운전자 연령대별 안전수준 비교)

  • Cho, Won Bum;Jeong, Jun Hwa;Kim, Do Gyeong;Park, Won Il
    • International Journal of Highway Engineering
    • /
    • v.17 no.1
    • /
    • pp.129-142
    • /
    • 2015
  • PURPOSES : The purpose of this study is to suggest a basis for setting appropriate safety goals specifically related to the threshold zone luminance in a vehicular traffic tunnel. METHODS : In the test, drivers were divided into two groups. One group consisted of all drivers (average drivers) group with an age ratio of drivers holding domestic driver's license and driver group by age to produce threshold zone luminance in the tunnel. The threshold zone luminance produced as a result was used to analyze how it affects the safety level of each driver group and provide a basis for setting an appropriate safety criterion that can be used to determine threshold zone luminance. We used test equipment, test conditions, and ananalysis of threshold zone luminance identical to that reported by ChoandJung(2014) but the values of adaptation luminance in our analys is were expanded to range from100 to $10,000cd/m^2$. RESULTS : Adaptation luminance and threshold zone luminance are found to be related by a quadratic function. The threshold zone luminance needed by older drivers to ensure a certain safety level is significantly higher than that for drivers of other age brackets when adaptation luminance increases. 56% of older drivers are at an increased risk of an accident at the same luminance for which the safety level of average drivers is 75%. The safety level that can be achieved for older drivers increases to above 60% when threshold zone luminance level is set with the goal of attaining a safety level of more than 85% for average drivers. The safety level that can be attained for average drivers is above 90% when the threshold zone luminance is high enough to ensure over 75% in the safety level of older drivers. Results of this study are applicable to highways and others whose designed speed is 100 km/h. CONCLUSIONS : Threshold zone luminance determined on the basis of drivers having average visual ability is of limited value as a performance standard for ensuring the safety of older drivers. Hence, safety level for older drivers should be considered separately from safety levels for drivers with an average ability to avoid risk. Upward adjustment of older drivers' safety level in the process of determining appropriate threshold zone luminance in a vehicular traffic tunnel may bring both tangible and intangible benefit as a result of reducing accidents. However, there is an associated dollar cost arising from installing and operating lights. As a result, the economic impact of these trade-offs should also be considered.

Early Results of Extracardiac Fontan Operation (심장외폰탄수술의 조기성적)

  • 김웅한;정도현;김수철;전홍주;이창하;김욱성;오삼세;정철현;나찬영
    • Journal of Chest Surgery
    • /
    • v.31 no.7
    • /
    • pp.650-659
    • /
    • 1998
  • Between August 1996 and August 1997, 22 patients underwent extracardiac Fontan operations. The basic diagnoses included univentricular heart of the right ventricular type (n=12); univentricular heart of the left ventricular type (n=4); tricuspid atresia (n=4); left isomerism, transposition of great arteries, ventricular septal defect and pulmonary stenosis (n=1); and criss-cross heart with uneven ventricle (n=1). The median age of the 14 men and 8 women was 29 months (range from 21 months to 26 years). Previous procedures included bidirectional cavopulmonary shunt (n=15, interval=15.6$\pm$3.4 months), Kawashima operation (n=4, interval=37.5$\pm$20 months), and classic Glenn shunt (n=1, interval=14 years). In 2 patients, extracardiac Fontan operations were done without any previous procedures. A 16- to 22-mm flexible Gore-Tex tube graft (n=18), Hemashield graft (n=3), or, alternatively, a nonvalved aortic allograft (n=1) was cut and anastomosed end-to-end between inferior vena cava and undersurface of pulmonary artery using Gore-Tex or Prolene suture in a running fashion. In risk Fontan patients (n=12), a communication between the extracardiac conduit and the right atrium was constructed. In the most 13 recent patients, the procedures were done without cross-clamping of the aorta and with a beating heart. Operative mortality was 9.1% (n=2). Complications included persistent chest tube drainage for more than 7 days (n=5), chorea (n=2), and low cardiac output (n=1). There were no late deaths. Follow-up echocardiogram (mean: 6 months) demonstrated satisfactory hemodynamic results in the surviving 20 patients. Potential advantages of this technique consist of minimization of surgical manipulation of atrial tissue, reduction or elimination of myocardial ischemia, creationof a uniform and stable inferior vena cava-to-pulmonary artery conduit, and increased flexibility and safety in certain high-risk patients such as those with increased pulmonary vascular resistance, pulmonary hypertension, and impaired ventricular function. Further investigations during a longer follow-up are needed to confirm the intermediate and long-term results, especially the reduction of late atrial arrhythmias.

  • PDF

The Mean-VaR Framework and the Optimal Portfolio Choice (평균-VaR 기준과 최적 포트폴리오 선택)

  • Ku, Bon-Il;Eom, Young-Ho;Choo, Youn-Wook
    • The Korean Journal of Financial Management
    • /
    • v.26 no.1
    • /
    • pp.165-188
    • /
    • 2009
  • This paper has suggested the methodology for the frontier portfolios and the optimal portfolio under the mean-VaR framework, not assuming the normal distribution and considering the investor's preferences for the higher moments of return distributions. It suggested the grid and rank approach which did not need an assumption about return distributions to find the frontier portfolios. And the optimal portfolio was selected using the utility function that considered the 3rd and the 4th moments. For the application of the methodology, weekly returns of the developed countries index, the emerging market index and the KOSPI index were used. After the frontier portfolios of the mean-variance framework and the mean-VaR framework were selected, the optimal portfolios of each framework were compared. This application compared not only the difference of the standard deviation but also the difference of the utility level and the certainty equivalent expressed by weekly expected returns. In order to verify statistical significances about the differences between the mean-VaR and the mean-variance, this paper presented the statistics which were obtained by the historical simulation method using the bootstrapping. The results showed that an investor under the mean-VaR framework had a tendency to select the optimal portfolio which has bigger standard deviation, comparing to an investor under the mean-variance framework. In addition, the more risk averse an investor is, the bigger utility level and certainty equivalent he achieves under the mean-VaR framework. However, the difference between the two frameworks were not significant in statistical as well as economic criterion.

  • PDF

Reliability Analysis of a Quay Wall Constructed on the Deep-Cement-Mixed Ground(Part I: External Stability of the Improved Soil System) (심층혼합처리지반에 설치된 안벽의 신뢰성해석(Part I: 개량지반의 외부안정))

  • Huh, Jung-Won;Park, Ock-Joo;Kim, Young-Sang;Hur, Dong-Soo
    • Journal of Korean Society of Coastal and Ocean Engineers
    • /
    • v.22 no.2
    • /
    • pp.79-87
    • /
    • 2010
  • This is the first of the two papers dealing with reliability analyses for external and internal stability of a quay wall constructed on a special foundation. A new practical reliability analysis method is proposed in this paper to evaluate the quantitative risk associated with external stability of a quay wall constructed on the deep cement mixed ground. The method can consider uncertainties in various design variables. For the risk estimation to external stability of the improved soil-quay wall, three corresponding limit state functions of sliding, overturning and bearing capacity are fully defined by introducing concept of the secondary random variable. Three representative reliability methods, MVFOSM, FORM and MCS are then applied to evaluate the failure probabilities of the three limit state functions explicitly expressed in terms of the basic and secondary random variables. From the reliability analysis results, the failure probabilities obtained from the three approaches are very close to each other, and the sliding failure mode appears to be the most critical when the earthquake loading is under consideration.

Reliability Assessment of Fatigue Crack Propagation using Response Surface Method (응답면기법을 활용한 피로균열진전 신뢰성 평가)

  • Cho, Tae Jun;Kim, Lee Hyeon;Kyung, Kab Soo;Choi, Eun Soo
    • Journal of Korean Society of Steel Construction
    • /
    • v.20 no.6
    • /
    • pp.723-730
    • /
    • 2008
  • Due to the higher ratio of live load to total loads of railway bridges, the accumulated damage by cyclic fatigue is significant. Moreover, it is highly possible that the initiated crack grows faster than that of highway bridges. Therefore, it is strongly needed to assess the safety for the accumulated damage analytically. The initiation and growth of fatigue-crack are related with the stress range, number of cycles, and the stiffness of the structural system. The stiffness of the structural system includes uncertainties of the planning, design, construction and maintenance, which varies as time goes. In this study, the authors developed the design and risk assessment techniques based on the reliability theories considering the uncertainties in load and resistance. For the probabilistic risk assessment of crack growth and the remaining life of the structures by the cyclic load of railway and subway bridges, response surface method (RSM) combined with first order second moment method were used. For composing limit state function, the stress range, stress intensity factor and the remaining life were selected as input important random variables to the RSM program. The probabilities of failure and the reliability indices of fatigue life for the considered specimen under cyclic loads were evaluated and discussed.

Human and Animal Study on the Natural Food for Obesity and Metabolic Syndrome Risk Factors (비만 및 대사성증후군 위험인자에 대한 천연물 식품의 인체 및 동물 효능연구)

  • 문근아;최선미;김선형;김성수;강지연;윤유식
    • Journal of the Korean Society of Food Science and Nutrition
    • /
    • v.32 no.8
    • /
    • pp.1394-1400
    • /
    • 2003
  • In this study a natural composition containing oriental herbs, KSH28, for reducing obesity and metabolic syndrome was constructed and its efficacy was evaluated in animal and human. To investigate the anti-obesity effect of KSH28, animal study was conducted using high fat diet-induced obese mice. KSH28 significantly decreased body weight and adipose tissue in high fat diet-fed obese mice. The mean size of fat cells in adipose tissue was significantly reduced. Glucose and triglyceride levels were also significantly decreased. To elucidate its efficacy in human, a natural food containing KSH28 with grains, vegetables, vitamins, minerals and dietary fibers was constructed and 40 subjects (8 male and 32 female) were tested for the change of body composition, blood pressure and blood lipid profile. All subjects had 2 pack (309 each) of natural food per day for 4 weeks. Compared to the baseline value, body fat was significantly reduced, however, water, protein and mineral contents in the body were not changed, suggesting selective reduction of fat tissue. Blood pressure and serum lipid profile were significantly decreased to reduce risk for metabolic syndrome. Serum GPT, a liver function indicator, was not changed and no significant side effects were detected. Therefore, it was shown that the KSH28 is a safe and effective composition for reducing obesity and metabolic syndrome.