Risk Analysis Research Papers - Academia.edu (original) (raw)

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- Strategy, Risk Analysis, Disasters, Policies
- by Nicolaas Broersen
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- Risk Analysis

Woods, M. (2011). Risk Management in Organizations-An integrated case study approach. New York: Routledge.

İnşaat, İnşaat Sektörü, Fiziksel Risk Etmenleri, Risk, Tehlike, İş Güvenliği, İş Kazası, Risk Analizi, Fine Kinney metodu, İş Sağlığı ve Güvenliği, Occupational Health and Safety, İş Güvenliği Uzmanlığı, İş Güvenliği Uzmanı, Mühendislik, Engineering, İş Kazaları, İşçi Sağlığı, İnşaat Sektörü, İstanbul, Türkay Ercan Şengöz (Türkay Ercan Şengöz tarafından yayımlanan her çeşit harita, bilgi ve belgelerin her hakkı saklıdır. Her ne şekilde ve amaçla olursa olsun bu bilgi ve belgelerin kaynak belirtilmeden kullanılması, yazılı izin alınmadan elektronik, optik, mekanik veya diğer yollarla dağıtılması, çoğaltılması, basılması, değiştirilmesi, paylaşılması, kopyalanması ve internet sitelerinde kullanılması durumunda gerekli hukuki yollara başvurulacak ve yasal işlem başlatılacaktır. Önemle duyurulur. Bu platformda veya diğer platformlarda paylaşmış olduğum tez veya akademik kapsamdaki çalışmalarımın içerisindeki bütün bilgilerin etik davranış ve akademik kurallar çerçevesinde elde edilerek sunulduğunu, akademik çalışmalarımın tez yazım kurallarına uygun olarak hazırlandığını hatırlatıyor, bana ait olan her türlü ifade ve bilginin kaynağına eksiksiz atıf yapılması gerektiğini bildiriyor, sevgi ve saygılarımı sunuyorum.)

- by Türkay Ercan Şengöz
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- Engineering, Civil Engineering, Geology, Occupational Health
- by Xinjia chen
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- Applied Mathematics, Computer Science, Randomized Algorithms, Statistics
- by Paolo Ricci
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- Multidisciplinary, Risk Analysis, Risk factors, Neoplasms

A novel real-time quantitative PCR (QPCR) assay is described for monitoring CMV DNA load in clinical specimens using the LightCycler™. The assay is rapid ( B 40 min), easy to carry out, robust, reliable and is capable of detecting from 10 to over 2 ×10 5 CMV DNA copies with a wide linear range. Amplification and detection occur simultaneously, avoiding the need for post-PCR analysis and thereby minimising the risk of carryover contamination. The assay proved to be accurate, specific and reproducible when evaluated in three different laboratories. In addition, LightCycler™ results were comparable with those of TaqMan™, an independent real-time QPCR assay.

- by Guiver C
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- Microbiology, Medical Microbiology, Risk, Quantitative PCR
- by Michael Dourson and +2
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- Algorithms, Monte Carlo, Risk, Multidisciplinary

Low body mass index (BMI) is a well-documented risk factor for future fracture. The aim of this study was to quantify this effect and to explore the association of BMI with fracture risk in relation to age, gender and bone mineral density (BMD) from an international perspective using worldwide data. We studied individual participant data from almost 60,000 men and women from 12 prospective population-based cohorts comprising Rotterdam, EVOS/EPOS, CaMos, Rochester, Sheffield, Dubbo, EPIDOS, OFELY, Kuopio, Hiroshima, and two cohorts from Gothenburg, with a total follow-up of over 250,000 person years. The effects of BMI, BMD, age and gender on the risk of any fracture, any osteoporotic fracture, and hip fracture alone was examined using a Poisson regression model in each cohort separately. The results of the different studies were then merged. Without information on BMD, the age-adjusted risk for any type of fracture increased significantly with lower BMI. Overall, the risk ratio (RR) per unit higher BMI was 0.98 (95% confidence interval [CI], 0.97-0.99) for any fracture, 0.97 (95% CI, 0.96-0.98) for osteoporotic fracture and 0.93 (95% CI, 0.91-0.94) for hip fracture (all p <0.001). The RR per unit change in BMI was very similar in men and women (p >0.30). After adjusting for BMD, these RR became 1 for any fracture or osteoporotic fracture and 0.98 for hip fracture (significant in women). not linearly distributed across values for BMI. Instead, the contribution to fracture risk was much more marked at low values of BMI than at values above the median. This nonlinear relation of risk with BMI was most evident for hip fracture risk. When compared with a BMI of 25 kg/m 2 , a BMI of 20 kg/m 2 was associated with a nearly twofold increase in risk ratio (RR=1.95; 95% CI, 1.71-2.22) for hip fracture. In contrast, a BMI of 30 kg/ m 2 , when compared with a BMI of 25 kg/m 2 , was associated with only a 17% reduction in hip fracture risk (RR=0.83; 95% CI, 0.69-0.99). We conclude that low BMI confers a risk of substantial importance for all fractures that is largely independent of age and sex, but dependent on BMD. The significance of BMI as a risk factor varies according to the level of BMI. Its validation on an international basis permits the use of this risk factor in case-finding strategies.

- by John Eisman
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- Rheumatology, Fracture, Risk, Risk Analysis
- by Timothy McDaniels
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- Economics, Perception, Water, Risk

The concept of covert channels has been visited frequently by academia in a quest to analyse their occurrence and prevention in trusted systems. This has lead to a wide variety of approaches being developed to prevent and identify such channels and implement applicable countermeasures. However, little of this research has actually trickled down into the field of operational security management and risk analysis. Quite recently a number of covert channels and enabling tools have appeared that did have a significant impact on the operational security of organizations. This paper identifies a number of those channels and shows the relative ease with which new ones can be devised. It identifies how risk management processes do not take this upcoming threat into account and suggests where improvements would be helpful.

... Suprasad V. Amari, Member, IEEE ... Notation label of component , [failure, repair] rate of component system-failure frequency mean number of system-failures per time-unit , Boolean variable indicating that component is [working,... more

- by Suprasad Amari
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- Engineering, Computer Science, Engineering Management, Technology Management

Despite the widespread adoption of software diversity in some industries, there is still controversy about its benefits for reliability, safety or security. We take the prospective of diversity as a risk reduction strategy, in face of the uncertainty about the dependability levels delivered by software development. We specifically consider the problem faced at the start of a project, when the assessment of potential benefits, however uncertain, must determine the decision whether to adopt diversity. Using probabilistic modelling, we discuss how different application areas require different measures of the effectiveness of diversity for reducing risk. Extreme values of achieved reliability, and especially, in some applications, the likelihood of delivering "effectively fault-free" programs, may be the dominant factor in this effect. Therefore, we cast our analysis in terms of the whole distribution of achieved probabilities of failure per demand, rather than averages, as usually done in past research. This analysis highlights possible and indeed frequent errors in generalizations from experiments, and identifies risk reduction effects that can be proved to derive from independent developments of diverse software versions. Last, we demonstrate that, despite the difficulty of predicting the actual advantages of specific practices for achieving diversity, the practice of "forcing" diversity by explicitly mandating diverse designs, development processes, etc., for different versions, rather than just ensuring separate development, is robust, in terms of worst-case effects, in the face of uncertainty about the reliability that the different methods will achieve in a specific project, a result with direct applicability to practice.

- by Andrey Povyakalo
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- Engineering, Computer Science, Software Security, Software Development

The liberalization of electricity markets has forced energy producing companies and traders to calculate costs closer to the profit frontier. Thus, an efficient risk management and risk controlling are needed to ensure the financial survival even during bad times. Using the RAROC methodology we provide a new framework to quantify risks related to wholesale electricity contracts, also called full load contracts. We do not only consider risk of market price fluctuations but also correlation effects between the spot market price and the load curve of a customer. We further conduct an empirical study on whole sale contracts for industry customers and public utility companies of a German energy provider. Our findings support the adequateness of the approach and point out the importance of considering also price-volume correlation effects for electricity whole sale contracts.

- by Zari Rachev
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- Marketing, Mechanical Engineering, Energy Economics, Methodology

This paper intends to present a contribution to the development of techniques of decision-making in international projects of exploration and production of petroleum. A case study of the Multi-Attribute Utility Theory (MAUT) was developed and applied to define priorities among ten offshore exploration investment opportunities around the world offered to a Brazilian petroleum multinational company, according to decision-makers' preferences. The MAUT model proposed shows for the first time a combination of operational, political and technological risks, resulting in a quite complete formulation to describe quantitatively the decision-making process. It is important to emphasize that this paper presents an unpublished model to evaluate political risks whose detailed analysis is currently of extreme importance for international investments in petroleum projects.

- by Lucio Carpio
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- Technology, Production, Decision support system, Risk Analysis

Characterizing the doseeeffect relationship and estimating acceptable exposure levels are the primary goals of quantitative risk assessment. A semiparametric approach is proposed for risk assessment with continuously measured or quantitative outcomes which has advantages over existing methods by requiring fewer assumptions. The approach is based on pairwise ranking between the response values in the control group and those in the exposed groups. The work generalizes the rank-based Wilcoxon-Mann-Whitney test, which for the two-group comparison is effectively a test of whether a response from the control group is different from (larger than) a response in an exposed group. We develop a regression framework that naturally extends this metric to model the dose effect in terms of a risk function. Parameters of the regression model can be estimated with standard software. However, inference requires an additional step to estimate the variance structure of the estimated parameters. An effective dose (ED) and associated lower confidence limit (LED) are easily calculated. The method is supported by a simulation study and is illustrated with a study on the effects of aconiazide. The method offers flexible modeling of the dose effect, and since it is rank-based, it is more resistant to outliers, nonconstant variance, and other departures from normality than previously described approaches.

- by Louise Ryan
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- Risk assessment, Multidisciplinary, Risk Analysis, Regression Analysis

Different international plant protection organisations advocate different schemes for conducting pest risk assessments. Most of these schemes use structured questionnaire in which experts are asked to score several items using an ordinal scale. The scores are then combined using a range of procedures, such as simple arithmetic mean, weighted averages, multiplication of scores, and cumulative sums. The most useful schemes will correctly identify harmful pests and identify ones that are not. As the quality of a pest risk assessment can depend on the characteristics of the scoring system used by the risk assessors (i.e., on the number of points of the scale and on the method used for combining the component scores), it is important to assess and compare the performance of different scoring systems. In this article, we proposed a new method for assessing scoring systems. Its principle is to simulate virtual data using a stochastic model and, then, to estimate sensitivity and specificity values from these data for different scoring systems. The interest of our approach was illustrated in a case study where several scoring systems were compared. Data for this analysis were generated using a probabilistic model describing the pest introduction process. The generated data were then used to simulate the outcome of scoring systems and to assess the accuracy of the decisions about positive and negative introduction. The results showed that ordinal scales with at most 5 or 6 points were sufficient and that the multiplication-based scoring systems performed better than their sum-based counterparts. The proposed method could be used in the future to assess a great diversity of scoring systems.

- by Mittinty Murthy
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- Monte Carlo Simulation, Invasive Species, Multidisciplinary, Risk Analysis

This paper examines both the benefits of choosing an internationally diversified portfolio and the evolution of the portfolio risk in the context of the current global financial crisis. The portfolio is comprised of three benchmark indexes from Romania, UK and USA. Study results show that on the background of a global economic climate eroded strongly by the effects of the current financial crisis, international diversification does not reduce risk. Moreover, using ARCH and GARCH models shows that the evolution of portfolio volatility is influenced by the effects of the current global financial crisis.

- by Stelian Stancu
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- Global Financial Crisis, Financial Crisis, Risk Analysis, ARCH model

This paper describes the results of an analysis of the effectiveness of the U.S. Count Guard's efforts to promote the safety of life and property at sea through its program to inspect large, ocean-going vessels. The effectiveness of specific U.S. Coast Guard vessel inspection activities was evaluated using risk based metrics that linked categories of root causes of accidents to the particular inspection activities designed to reduce the risk of each root cause category. The results demonstrate a risk-based ranking of USCG inspection activities. These metrics, describes as measures of effectiveness(MOE's) , yield insights regarding the most beneficial areas in which to concentrate inspection resources. Insights regarding quality of vessel casualty investigation data and database design as related to riskbased importance analysis are also described. The MOE's constructed in this study are specific to the USCG's Marine Inspection and Boarding Program, but the methodology of the study is based on sound theoretical principles that are probably applicable to a range of maritime safety activities. Hence the methodology applies equally to other important governmental regulatory programs and can be similarly used to measure their effectiveness and as an aid to decision-making.

- by Kishore Gawande
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- Economics, Risk, Multidisciplinary, Risk Analysis
- by S Kumar
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- Cloud Computing, Risk Analysis, Data Security, Data Processing
- by Marcelo J . Souza
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- Environmental Health, Public Health, Risk assessment, Risk Analysis

Several Melaleuca (Myrtaceae) species are invasive globally. Recently an increase in invasive species from this genus have been reported in South Africa. Here we document the first detailed assessment of the distribution and invasive potential of Melaleuca rugulosa in South Africa. We assess population structure, determine the current and potential future distribution in South Africa using climatic variables, conduct a risk analysis, provide recommendations for management, and consider the feasibility of eradication. We found one naturalising population of »665 individuals covering more than 1.2 hectares. It was first recorded in 1961 invading the native fynbos vegetation in the Table Mountain National Park (TMNP). Two recent fires in 2009 and 2016 likely enhanced spread, this spread happened despite undocumented clearing attempts in the last decade. The south-western Cape is the most climatically suitable for M. rugulosa, with most other wetter areas of the country being only partly suitable regions. The risk analysis indicated a medium risk, and we suggest listing M. rugulosa as category 1a (eradication target) under the South African National Environmental Management: Biodiversity Act (10/ 2004). Given the small area occupied, ease of access and the lack of a soil seed bank, the population can be extirpated from Devil’s Peak within the TMNP. We highlight that serotinous alien species, particular from the Myrtaceae, should receive more attention as potential invasive species in fire-driven ecosystems and that their lack of invasiveness in areas where fire is suppressed, should not be misinterpreted as being a low-risk species.

- by chelsey matthys
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- Plant Biology, Ecology, Fire, Biological invasions

Safety of the street foods is an important aspect in the field of nutrition security. A study was conducted in the city of Varanasi in India. It was observed that about 42% of the working man and women in the age group of 25-45, and 61%... more

- by sunita mishra
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- Food Safety, Food Security, Risk Analysis, Developing Country

Modelling the risk of infections from land application of biosolids is important to improve microbial safety regulations as well as to support public confidence in the agricultural use of biosolids for food production. The effect of the incidence of enteric disease on potential risk to human health from the agricultural use of mesophilic anaerobically digested biosolids was investigated for the state of Victoria. A model was developed to follow the partitioning and decay of nine pathogens from the estimated pathogen loads in the population through to annual exposure from ingestion of uncooked root crops grown in biosolids-amended soil. Dose-response relationships were used to estimate the annual risk of infection. Pathogen risks from land application of anaerobically digested biosolids were shown to be below the USEPA limits for drinking water.

- by Duncan A Rouch
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- Water, Risk Analysis, Biosolids

agulase-negative staphylococci, Enterobacter spp. and Pseudomonas aeruginosa . The overall incidence of bacteremic episodes was 0.514/1,000 catheter days. Hypertension, atherosclerosis, diabetes mellitus, site of catheter implantation, duration of catheter use, Wright-Khan comorbidity index and previous history of CRB were significant risk factors associated with bacteremia in univariate analysis. Multivariate analysis revealed that a previous history of a bacteremic episode (odds ratio, OR = 2.70, 95% confidence interval, CI = 1.56-4.68), diabetes mellitus (OR = 2.37, 95% CI = 1.65-3.39), duration of catheter use 1 90 days (OR = 1.85, 95% CI = 1.35-2.55) and hypertension (OR = 1.49, 95% CI = 1.08-2.04) were still significant factors associated with bacteremia. Conclusion: Reducing CRB is still a challenge for nephrologists to reduce patient morbidity and mortality. Our study could demonstrate that diabetes, previous history of CRB, site of catheter implantation and duration of catheter use were the most important risk factors for bacteremia. Therefore, to prevent CRB, particular attention should be paid to patients with diabetes and a previous history of bacteremia following strict hygienic and aseptic rules for catheter handling associated with the regular use of antiseptic lock solutions.

- by Bernard Canaud
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- Adolescent, France, Catheterization, Multivariate Analysis

Risk is defined as the probability of a specific adverse event occurring within a specific period, while Quantitative risk assessment (QRA) is the development of a quantitative estimate of risk based on engineering evaluation and mathematical techniques by combining estimate of incident consequences and frequencies. In view of the increase in the use of railways as the mode of transportation for hazardous materials throughout the world, the associated risk analysis should be taken into concern. In this study, the failure frequency of the transportation of ammonia from the Petronas fertilizers Kedah (PFK) plant in Gurun (Northern part of Peninsular Malaysia), to the Chemical Company Malaysia (CCM) fertilizer's facilities in Port Klang (South-western part of Peninsular Malaysia) was evaluated by incorporating the human error assessment. The study highlighted the importance of human error contributions in the failure frequency analysis and its impact on the selected failure scenarios. Besides, it also shows that the application of the human error assessment and reduction technique (HEART), which is a useful human reliability analysis tool, should be used in parallel with the fuzzy arithmetic approach to reduce the uncertainties involved in the estimation of human error probabilities, and hence, to reduce the likelihood of incorrect risks estimates being assessed. The results suggested that the commonly applied approach in quantitative risk assessments, which only consider equipment failures in the failure frequency estimations, are clearly an underestimate of the potential causes of failures leading to hazardous material releases, and hence, the calculated risks based do not reflect the actual risks. © 2008 American Institute of Chemical Engineers Process Saf Prog, 2009

- by noor sulaiman
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- Chemical Engineering, Railway Transport, Malaysia, Fuzzy Sets
- by Lauren Zeise
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- Risk assessment, Multidisciplinary, Disease susceptibility, Monte Carlo Simulations

This is the 14th report in a series of periodic general reports on mortality in the Life Span Study (LSS) cohort of atomic bomb survivors followed by the Radiation Effects Research Foundation to investigate the late health effects of the radiation from the atomic bombs. During the period 1950-2003, 58% of the 86,611 LSS cohort members with DS02 dose estimates have died. The 6 years of additional follow-up since the previous report provide substantially more information at longer periods after radiation exposure (17% more cancer deaths), especially among those under age 10 at exposure (58% more deaths). Poisson regression methods were used to investigate the magnitude of the radiation-associated risks, the shape of the dose response, and effect modification by gender, age at exposure, and attained age. The risk of all causes of death was positively associated with radiation dose. Importantly, for solid cancers the additive radiation risk (i.e., excess cancer cases per 10 4 person-years per Gy) continues to increase throughout life with a linear dose-response relationship. The sex-averaged excess relative risk per Gy was 0.42 [95% confidence interval (CI): 0.32, 0.53] for all solid cancer at age 70 years after exposure at age 30 based on a linear model. The risk increased by about 29% per decade decrease in age at exposure (95% CI: 17%, 41%). The estimated lowest dose range with a significant ERR for all solid cancer was 0 to 0.20 Gy, and a formal dose-threshold analysis indicated no threshold; i.e., zero dose was the best estimate of the threshold. The risk of cancer mortality increased significantly for most major sites, including stomach, lung, liver, colon, breast, gallbladder, esophagus, bladder and ovary, whereas rectum, pancreas, uterus, prostate and kidney parenchyma did not have significantly increased risks. An increased risk of non-neoplastic diseases including the circulatory, respiratory and digestive systems was observed, but whether these are causal relationships requires further investigation. There was no evidence of a radiation effect for infectious or external causes of death.

- by Donald Pierce
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- Radiation, Nuclear Weapons, Modeling, Risk

Assessments of public perceptions of the characteristics of a nuclear power plant accident and affective responses to its likelihood were conducted 5 months before and 1 month after the Chernobyl accident. Analyses of data from 69 residents of southwestern Washington showed significant test-retest correlations for only 10 of 18 variables-accident likelihood, three measures of impact characteristics, three measures of affective reactions, and hazard knowledge by governmental sources. Of these variables, only two had significant changes in mean ratings; frequency of thought and frequency of discussion about a nearby nuclear power plant both increased. While there were significant changes only for two personal consequences (expectations of cancer and genetic effects), both of these decreased. The results of this study indicate that more attention should be given to assessing the stability of risk perceptions over time. Moreover, the data demonstrate that experience with a major accident can actually decrease rather than increase perceptions of threat.

- by Michael Lindell
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- Genetics, Public Opinion, Survey Research, Risk assessment

Objective: Though the surgical treatment of esophageal cancer is increasingly accepted for elderly people defined as aged over 70 years, less is reported about the results in patients over 75. This study is a single institution retrospective analysis of outcome after esophagectomy for cancer of the esophagus and GEJ in patients aged over 75 years. Methods: All consecutive patients 76 years old and over undergoing curative esophagectomy for cancer in the period 1991-2006 were analyzed as to comorbidities, outcome and long-term survival. All the data had been prospectively collected in a database. Postoperative mortality risk was assessed by P-POSSUM and O-POSSUM score for in-hospital mortality and by the recently published Steyerberg's score system [Steyerberg EW, Neville BA, Koppert LB, Lemmens VEPP, Tilanus HW, Coebergh JWW, Weeks JC, Earle CC. Surgical mortality in patients with esophageal cancer: development and validation of a simple risk score. J Clin Oncol 2006;24:4277-84.] for 30-day mortality. Five-year survival was compared to the standardized survival in the general population. Results: One hundred and eight patients fulfilling the abovementioned criteria were found (76 males and 32 females, mean age 79.5 years, mean standardized life-expectancy: 7.36 years). Among them, 69% had esophageal tumors and 31% GEJ tumors. The predominant histology was adenocarcinoma (74%). Eighty-six (79.6%) presented with one or more major comorbidities or a history of previous major upper-GI surgery, potentially affecting the surgical outcome. All underwent resection with curative intent (R 0 83.3%, R 1 12%, R 2 4.6%). The overall postoperative morbidity rate was 51.9%, pulmonary complications (37%) being the most frequent. Postoperative mortality, mainly due to cardiopulmonary complications, was 7.4%, which was consistent with that predicted by P-POSSUM score (7.2%) and lower than that predicted by O-POSSUM score (15.1%). Thirty-day mortality was 5.5%, being consistent with that predicted by the Steyerberg's score (6.8%). Overall 5-year survival was 35.7%, while R 0 overall survival 42% and cancer specific R 0 survival 51.7%. Conclusions: Patients 76 years old and over with esophageal or GEJ cancer should not be denied surgery solely on the basis of age. Outcome and long-term results in the selected elderly are not differing from those reported for younger patients. However, despite thorough preoperative assessment being applied in the selection of the candidates for surgery, a practical and reliable individual riskanalysis stratification is still lacking. #

- by Paul Leyn and +2
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- Treatment Outcome, Stratification, Risk Analysis, Elderly People

This study examined to what extent nuclear risk perceptions, organizational commitment (OC), and appraisals of management are associated with each other among nuclear power plant personnel. The sample consisted of 428 nuclear power plant workers who completed a questionnaire at their workplace. Perceived nuclear risk and OC were most closely related to the appraisals of the top management of the organization. As the trust in and satisfaction with the top management increased, perceived nuclear safety and acceptance of the organizational goals and values heightened. This result is discussed in the context of industrial safety management.

- by Raija Kalimo
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- Public Opinion, Organizational Commitment, Multidisciplinary, Risk Analysis
- by Bryan Hubbell
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- Multidisciplinary, Risk Analysis

With 5-7 month long duration missions at 51.6°inclination in Low Earth Orbit, the ionizing radiation levels to which International Space Station (ISS) crewmembers are exposed will be the highest planned occupational exposures in the world. Even with the expectation that regulatory dose limits will not be exceeded during a single tour of duty aboard the ISS, the ''as low as reasonably achievable'' (ALARA) precept requires that radiological risks be minimized when possible through a dose optimization process. Judicious placement of efficient shielding materials in locations where crewmembers sleep, rest, or work is an important means for implementing ALARA for spaceflight. Polyethylene (C n H n ) is a relatively inexpensive, stable, and, with a low atomic number, an effective shielding material that has been certified for use aboard the ISS. Several designs for placement of slabs or walls of polyethylene have been evaluated for radiation exposure reduction in the Crew Quarters (CQ) of the Zvezda (Star) Service Module. Optimization of shield designs relies on accurate characterization of the expected primary and secondary particle environment and modeling of the predicted radiobiological responses of critical organs and tissues. Results of the studies shown herein indicate that 20% or more reduction in equivalent dose to the CQ occupant is achievable. These results suggest that shielding design and risk analysis are necessary measures for reducing long-term radiological risks to ISS inhabitants and for meeting legal ALARA requirements. Verification of shield concepts requires results from specific designs to be compared with onboard dosimetry.

- by Mark Shavers
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- Mechanical Engineering, Aerospace Engineering, Risk, Radiation Protection

he increasing complexity of oil and gas installations and operations, along with growing public awareness to ensure higher levels of safety, has put great pressure on the designers and operators to find innovative solutions to ensure safe as well as economically viable operation. Risk-based inspection and maintenance helps in finding such solutions and thus in gaining more importance in the industries. A wide range of methodologies currently in use for risk-based inspection includes commercial and in-house software packages (specific to individual plants). The techniques with software produce very different results, raising serious concerns. A recent benchmarking study conducted by the British Health and Safety Laboratory has confirmed the lack of a coherent approach as well as wide variation in the results of the case studies conducted by different agencies. Here, we present a simple and structured risk-based inspection and maintenance methodology that can bridge this gap. The proposed methodology uses fuzzy logic to estimate risk by combining (fuzzy) likelihood of occurrence of and its (fuzzy) consequence. The methodology is based on aggregative risk analysis and multi-attribute decision-making. Application and effectiveness of the proposed methodology is demonstrated using four case studies conducted earlier by different agencies. The results obtained are fairly consistent with little variation and the sensitivity of the proposed method is also discussed in the paper.

- by Faisal Khan
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- Engineering, Chemical Engineering, Fuzzy, Risk Analysis

The increase of international trade across countries and borders results in increased risks associated with the inflow of new pests and diseases. These risks are likely to be increased more rapidly due to climate change. Some countries implement strict regulations on imports to prevent these risks and protect biosecurity, food safety, and public health. However, the problems arise when the diseases and pests are found in a country where their economic structure largely depends on agricultural exports and cause ripple effects on other industries and ecosystems. Therefore, establishing an effective quarantine system is essential to protect and recover from the damage caused by non-native diseases and pests. This study's objectives are 1) analyzing the agricultural policies relate to the quarantine system on diseases and pests in Korea, 2) evaluating the Korea plant quarantine system's value, and 3) simulating plant quarantine policy strategies. We estimated the Korean quarantine system's benefits on diseases and pests to reach these objectives. The benefits are measured with a willingness to pay from respondents surveyed by the contingent valuation method (CVM). The CVM approach directly asks people how much they would willingly pay for food security. Finally, the Korean quarantine system's values are simulated with several policy scenarios and different scales of infection at the regional level. The results of this study can deliver policy implications on the quarantine system innovation in developing countries including Asia.

- by Minsu Son
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- Markov-chain model, Risk Analysis, Quarantine, Contingent Valuation Method (CVM)

The estimation of chemical concentrations in wildlife foods, such as plant foliage, is often performed for risk assessments at contaminated sites. Regression models and uptake factors for use in estimating the uptake of inorganic elements from soil by above-ground plant tissues were derived in this study. These included models for arsenic, cadmium, copper, lead, mercury, nickel, selenium, and zinc. Models were developed using published data from soil contaminated in the field and were validated using measured concentrations from two contaminated sites. Single-variable regression models of log-transformed concentrations in plants versus log-transformed concentrations in soil are generally recommended over simple uptake factors for use in estimating plant uptake of inorganic contaminants in ecological risk assessments. Multiple regression models with soil concentration and pH as the variables are also recommended for estimating the uptake of four chemicals (cadmium, mercury, selenium, and zinc) by plants. Models for use in screening risk assessments, i.e., the upper 95% prediction limits on the regressions, are recommended to provide conservative estimates of uptake of inorganic chemicals by plants.

- by Glenn Suter
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- Bioaccumulation, Risk assessment, Comparative Study, Soil Pollution

Authority to support a strategy of in-place management of the disposal area for another decade. The QRA methodology adopted for this first of a kind application was a scenario-based approach in the framework of the triplet definition of risk (scenarios, likelihoods, consequences). The measure of risk is the frequency of occurrence of different levels of radiation dose to humans at prescribed locations. The risk from each scenario is determined by (1) the frequency of disruptive events or natural processes that cause a release of radioactive materials from the disposal area; (2) the physical form, quantity, and radionuclide content of the material that is released during each scenario; (3) distribution, dilution, and deposition of the released materials throughout the environment surrounding the disposal area; and (4) public exposure to the distributed material and the accumulated radiation dose from that exposure. The risks of the individual scenarios are assembled into a representation of the risk from the disposal area. In addition to quantifying the total risk to the public, the analysis ranks the importance of each contributing scenario, which facilitates taking corrective actions and implementing effective risk management. Perhaps most importantly, quantification of the uncertainties is an intrinsic part of the risk results. This approach to safety analysis has demonstrated many advantages of applying QRA principles to assessing the risk of facilities involving hazardous materials.

- by John Stetkar
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- Waste Management, Public Health, Risk assessment, Multidisciplinary

As an emerging domain of risk research, nanotechnologies engender novel research questions, including how new technologies are encountered given different framing and contextual detail. Using data from a recent U.S. national survey of perceived risks (N= 1,100), risk versus benefit framings and the specific social positions from which people encounter or perceive new technologies are explored. Results indicate that vulnerability and attitudes toward environmental justice significantly influenced risk perceptions of nanotechnology as a broad class, while controlling for demographic and affective factors. Comparative analyses of different examples of nanotechnology applications demonstrated heightened ambivalence across acceptability when risk versus benefit information was provided with application descriptions (described in short vignettes as compared to the general category “nanotechnology,” absent of risk or benefit information). The acceptability of these nano-specific vignettes varied significantly in only some cases given indexes of vulnerability and attitudes toward environmental justice. However, experimental narrative analyses, using longer, more comprehensive descriptive passages, show how assessments of risks and benefits are tied to the systematically manipulated psychometric qualities of the application (its invasiveness and controllability), risk messaging from scientists, and the social implications of the technology with regard to justice. The article concludes with discussion of these findings for risk perception research and public policy related to nanotechnology and possibly other emerging technologies.

- by ESD Social Justice
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- Social Justice, Risk Analysis

Nasr City (Egypt) was considered one of the most critical areas in Greater Cairo till the second half of year 2005. Prior to that date, the Greater Cairo Potable Water Company has installed new facilities that ended all hydraulic problems occurred in the system under normal conditions. Although the system is currently working properly without any problem, some risk conditions such as pipeline breakage, valve breakage, pump failure, or tank failure cause service interruption. With people’s luxury developing, service unavailability is no longer acceptable, thus, the system should provide the service under risk condition without massive increase of the system cost and service unit price. In this paper, risk causes and risk analysis benefits had been reviewed and the Nasr City Water Distribution System was analyzed under several risk conditions. As a result, short term plan is recommended for minor risk causes that lead to local service unavailability. On the other hand, long term plan,...

- by Wael Khadr
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- Hydraulics, Water Distribution Systems, Risk Analysis, Water Distribution System
- by Gary McClelland and +1
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- Multidisciplinary, Risk Analysis

This paper considers the estimation of the mean vector of a p-variate normal distribution with unknown covariance matrix when it is suspected that for a p × r known matrix B the hypothesis = B , ∈ R r may hold. We consider empirical Bayes estimators which includes (i) the unrestricted unbiased (UE) estimator, namely, the sample mean vector (ii) the restricted estimator (RE) which is obtained when the hypothesis = B holds (iii) the preliminary test estimator (PTE), (iv) the James-Stein estimator (JSE), and (v) the positive-rule Stein estimator (PRSE). The biases and the risks under the squared loss function are evaluated for all the five estimators and compared. The numerical computations show that PRSE is the best among all the five estimators even when the hypothesis = B is true.

- by Muni Srivastava
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- Mathematics, Statistics, Multivariate Analysis, Risk Analysis

Recent transformations in design, planning and operation of distribution system represent the needed evolutionary step toward a modern integrated infrastructure where new riskbased operations balance economic and reliability criteria. Risk assessment tools are useful for monitoring and supervisory control because they provide operators with the capability to quantify the tradeoff between reliability and economic performance. One part of the risk assessment is the determination of financial impact that can be expressed through the total cost of energy supply interruption. The calculation of interruption cost is typically associated with planning assessment where several parameters essential to network operation are neglected. The proposed mathematical model incorporates time-dependent interruption events, and integrates the spatio temporal risk data using a GIS platform.

- by Jonatas Boas Leite
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- Computer Science, Risk Analysis, Electrical Power Distribution, Cost Function

A wastewater storage lagoon failed due to the development of a sinkhole at a site in the Lehigh River valley in Allentown, Pennsylvania (PA). The polluted wastewater from the lagoon entered into the underlying aquifer and moved within a narrow pathway controlled by cracks, fissures, and solution channels within the karstified Allentown Formation of the Cambrian Period. The Allentown Formation serves as the principal aquifer for the public water supply of the area. To develop appropriate remedial measures, a thorough understanding of the geologic setting was required. Therefore, a geologic and hydrogeologic characterization of the area was completed, aerial photography and satellite imagery interpretations were performed, stratigraphic core holes were drilled and geophysically logged, and the data correlated to define structural control and movement of ground water and pollutants. A number of wells were drilled and constructed, and water levels were monitored on a continuous basis to correlate with climatic changes and determine the direction of flow. Water samples were collected periodically and analyzed to delineate the vertical and lateral extent of migration of pollutants. Five saturated (water-bearing) zones were identified within the bedrock based on the analysis of cores and interpretation of geophysical logs. Ground water in the lower zones is polluted; the concentration of pollution increases with depth. Monitoring stations were established in the creek, south of the site, to measure flow rate several times during different seasons, and at different reaches, to determine the losing and gaining sections of the creek. Pumping tests were conducted to determine hydraulic characteristics of the aquifer. Based on the hydrogeologic model of the karstified aquifer, flow regime and structural control, a plan of action was defined and initiated to remediate the aquifer. The ground water is being remediated using a pump and treat methodology. The cleanup effort is continuous and the pollutant level is fluctuating with an overall-declining trend. The application of this technology has also created a pressure trough, thereby controlling off the site migration of pollutants.

- by Mary Pitts
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- Civil Engineering, Geology, Hydrogeology, Climate Change

In many cases, the manholes for maintaining various installations including power and telecommunication cables, water-, remote heating-, and gas-pipes are located in a close vicinity of power substations. The paper analyzes the risks of the occurrence of dangerous potential differences within the manhole and on the surrounding ground surface during ground faults in the substation. Possible protective measures are discussed.

- by Ivica Paunovic
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- Automatic Control, Power System Protection, Safety, Risk Analysis

Since 1971, a series of annual Environmental Surveillance. .. reports have served as the official public record of Los Alamos National Laboratory's (LANL) environmental performance. In northern New Mexico, where past LANL emissions are a public health concern, there is public skepticism over the accuracy of information contained in these reports. To test the hypothesis that LANL Environmental Surveillance. .. reports systematically understate past emissions, we compared the data on releases in LANL's own internal Occurrence Reports Collection (ORC) to the data reported to the public in the Environmental Surveillance. .. reports. A data set of 89 environmental occurrences recorded in the ORC in the time period from 1971 through 1980 was assembled. We did not find a systematic pattern of quantitative underreporting of source terms. However, 17 of the 89 (19%) environmental occurrences recorded in the ORC were not reported to the public in the Environmental Surveillance. .. reports. The observed discrepancies are discussed in terms of their relevance to public health concerns. Methodological caveats dictate restraint in applying these findings beyond the scope of the relative comparison performed here. Possible social origins for the rejected hypothesis are discussed. Areas for further consideration by the Centers for Disease Control's dose reconstruction study of LANL are identified.

- by K. Silver
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- Environmental Monitoring, Public Health, Risk assessment, Multidisciplinary

The growing necessity of organizations in using technologies to support to their operations implies that managing IT resources became a mission-critical issue for the health of the primary companies' businesses. Thus, in order to minimize problems in the IT infrastructure, possibly affecting the daily business operations, risks intrinsic to the change process have to be analyzed and assessed. Risk Management is a widely discussed subject in several areas, although for IT Change Management it is quite a new discipline. The Information Technology Infrastructure Library (ITIL) introduces a set of best practices to conduct the management of IT infrastructures. According to ITIL, risks should be investigated, measured, and mitigated before any change is approved. Even with these guidelines, there is no default automatic method for risk assessment in IT Change Management. In this paper we introduce a risk analysis method based on the execution history of past changes. In addition, we propose a failure representation model to capture the feedback of the execution of changes over IT infrastructures.

This paper describes a methodology of variation risk analysis for microsystems using analytical modelling and simulation, a key characteristic (KC) method and statistical analysis considering MEMS fabrication tolerances. This methodology is applied to an innovative design for a micro co-ordinate measuring machine (CMM) probe utilising piezoelectric actuation and sensing currently being developed at the National Physical Laboratory. Analytical modelling is used to investigate the individual effects of dimensional parameters on the sensors' open-circuit voltage output, which is a KC of the micro CMM probe. A computer simulation is performed using the finite-element method and compared with the analytical model. The KC variation is predicted and the variation contribution of the probe manufacturing processes is presented. This KC is mainly influenced by the thickness of the piezoelectric layer associated with the composite sol gel deposition process. Variation risk analysis results can be used to implement a variation risk mitigation strategy.

- by Richard Leach
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- Engineering, Statistical Analysis, Finite element method, Risk Analysis