The Experts below are selected from a list of 165 Experts worldwide ranked by ideXlab platform

A Stergachis - One of the best experts on this subject based on the ideXlab platform.

  • Overview of Cost‐Consequence Modeling in Outcomes Research
    Pharmacotherapy, 1995
    Co-Authors: A Stergachis
    Abstract:

    Outcomes research has developed in response to the need for information on costs, risks, and benefits of clinical treatments, including data regarding the effectiveness of prescription drugs. It attempts to consider more than the biologic effects of pharmaceuticals, that is, to encompass wider measures of the results of their use, issues that are not routinely addressed during clinical trials. Cost-effectiveness analysis compares the outcome of different treatment options in terms of monetary cost per unit of effectiveness. Examples of measures of effectiveness are years of life saved, number of days of hospitalization avoided, and number of treatment successes. Cost-Consequence models, also referred to as cost-outcome models, deal with costs and a variety of outcomes ranging from clinical to humanistic. Direct medical costs are those for prevention, detection, treatment, and rehabilitation; they are amounts spent to treat an illness, including hospitalization, professional services, pharmaceuticals, and medical supplies. Indirect medical costs are associated with changes in productivity, such as earnings lost because of illness. Humanistic outcomes deal primarily with functional status, quality of life, and satisfaction, and may include pain, anxiety, self-esteem, ability to carry out normal activities, and overall impressions. Since it is not possible to study all effects of treatments with clinical trials, Modeling techniques are useful in making therapeutic decisions.

  • Overview of cost-Consequence Modeling in outcomes research.
    Pharmacotherapy, 1995
    Co-Authors: A Stergachis
    Abstract:

    Outcomes research has developed in response to the need for information on costs, risks, and benefits of clinical treatments, including data regarding the effectiveness of prescription drugs. It attempts to consider more than the biologic effects of pharmaceuticals, that is, to encompass wider measures of the results of their use, issues that are not routinely addressed during clinical trials. Cost-effectiveness analysis compares the outcome of different treatment options in terms of monetary cost per unit of effectiveness. Examples of measures of effectiveness are years of life saved, number of days of hospitalization avoided, and number of treatment successes. Cost-Consequence models, also referred to as cost-outcome models, deal with costs and a variety of outcomes ranging from clinical to humanistic. Direct medical costs are those for prevention, detection, treatment, and rehabilitation; they are amounts spent to treat an illness, including hospitalization, professional services, pharmaceuticals, and medical supplies. Indirect medical costs are associated with changes in productivity, such as earnings lost because of illness. Humanistic outcomes deal primarily with functional status, quality of life, and satisfaction, and may include pain, anxiety, self-esteem, ability to carry out normal activities, and overall impressions. Since it is not possible to study all effects of treatments with clinical trials, Modeling techniques are useful in making therapeutic decisions.

Jay D. Johnson - One of the best experts on this subject based on the ideXlab platform.

  • An exploratory sensitivity study with the MACCS reactor accident Consequence model
    Reliability Engineering & System Safety, 1992
    Co-Authors: Jon C. Helton, J.l. Sprung, J.a. Rollstin, Jay D. Johnson
    Abstract:

    Abstract An exploratory sensitivity study with the MELCOR Accident Consequence Code System (MACCS) is presented. This study was performed to provide (1) an indication of the possible impact of Consequence Modeling uncertainties on the results of an integrated probabilistic risk assessment for a nuclear power station; (2) guidance on important parameters to direct data acquisition for future uncertainty analyses with MACCS; (3) a check that MACCS is operating as intended; and (4) insights on the effect of problem gridding on model resolution. The sensitivity results obtained in this study involve fatalities and injuries due to radiation exposure incurred within seven days of an accident and are based on the group of source terms (i.e. source term cluster) that made the largest contribution to early fatality risk in a probabilistic risk assessment for the Peach Bottom Atomic Power Station. The following Consequence measures were investigated: early fatalities, prodromal vomiting, lung impairment, population dose (0–500 miles), population dose (0–10 m iles), mean early fatality distance, maximum early fatality distance, mean early fatality risk, probability of one or more early fatalities, and amount of central processing unit (CPU) time required to evaluate MACCS. The analysis used techniques based on Latin hypercube sampling and regression analysis. Results obtained in this study indicate that (1) the impact of Consequence Modeling uncertainty in an integrated risk assessment may be significant; (2) dominant variables involving early health effects include evacuation area, scaling for horizontal dispersion, population relocation time, dry deposition velocity, and groundshine shielding; (3) the models in MACCS related to early health effects are implemented correctly; and (4) model resolution may be improved by finer radial gridding.

D.r. Stephens - One of the best experts on this subject based on the ideXlab platform.

  • Consequence Modeling for nuclear weapons probabilistic cost/benefit analyses of safety retrofits
    1998
    Co-Authors: T.f. Harvey, L. Peters, F.j.d. Serduke, C.h. Hall, D.r. Stephens
    Abstract:

    The Consequence models used in former studies of costs and benefits of enhanced safety retrofits are considered for (1) fuel fires; (2) non-nuclear detonations; and, (3) unintended nuclear detonations. Estimates of Consequences were made using a representative accident location, i.e., an assumed mixed suburban-rural site. We have explicitly quantified land- use impacts and human-health effects (e.g. , prompt fatalities, prompt injuries, latent cancer fatalities, low- levels of radiation exposure, and clean-up areas). Uncertainty in the wind direction is quantified and used in a Monte Carlo calculation to estimate a range of results for a fuel fire with uncertain respirable amounts of released Pu. We define a nuclear source term and discuss damage levels of concern. Ranges of damages are estimated by quantifying health impacts and property damages. We discuss our dispersal and prompt effects models in some detail. The models used to loft the Pu and fission products and their particle sizes are emphasized.

  • Consequence Modeling for nuclear weapons probabilistic cost benefit analyses of safety retrofits
    Other Information: PBD: 1 Jan 1998, 1998
    Co-Authors: T.f. Harvey, L. Peters, F.j.d. Serduke, C Hall, D.r. Stephens
    Abstract:

    The Consequence models used in former studies of costs and benefits of enhanced safety retrofits are considered for (1) fuel fires; (2) non-nuclear detonations; and, (3) unintended nuclear detonations. Estimates of Consequences were made using a representative accident location, i.e., an assumed mixed suburban-rural site. We have explicitly quantified land- use impacts and human-health effects (e.g. , prompt fatalities, prompt injuries, latent cancer fatalities, low- levels of radiation exposure, and clean-up areas). Uncertainty in the wind direction is quantified and used in a Monte Carlo calculation to estimate a range of results for a fuel fire with uncertain respirable amounts of released Pu. We define a nuclear source term and discuss damage levels of concern. Ranges of damages are estimated by quantifying health impacts and property damages. We discuss our dispersal and prompt effects models in some detail. The models used to loft the Pu and fission products and their particle sizes are emphasized.

Jeffrey D. Marx - One of the best experts on this subject based on the ideXlab platform.

  • the importance of multiphase and multicomponent Modeling in Consequence and risk analysis
    Journal of Hazardous Materials, 2003
    Co-Authors: David W Johnson, Jeffrey D. Marx
    Abstract:

    Abstract The ability to accurately predict the Consequences of a hazardous fluid release is dependent on three things: the knowledge of the modeler, the quality of the model that is used, and the quality of the input parameters. One of the most difficult problems in Consequence Modeling is the prediction of post-release multiphase behavior, especially when a multicomponent mixture is involved. Releases from gas/oil wells often fit this description. The wellstream will produce a light crude oil and a gas stream when flashed into a separator. If accidentally released to the atmosphere, the gas, aerosol, and liquid fractions rarely match the phase separations in the separator, or the expectations of the modeler. And, since the wellstream has a wide range of hydrocarbon components, the need to accurately predict the multicomponent behavior becomes more important. Over the years, modelers have used several “rules of thumb” to provide the source term input parameters for Modeling multiphase/multicomponent releases and subsequent dispersion. These Modeling assumptions can lead to hazard predictions that are very different from reality. The biggest problem with rules of thumb is their inability to account for thermodynamics; thus, they cannot approximate the phase splits and composition changes that do occur. The aim of this paper is to improve the knowledge of the modeler by providing some insight into the selection of the proper input parameters for multiphase releases of multicomponent fluids. The application of a multiphase release model with multicomponent thermodynamics to a wellstream release is used to illustrate the importance of good Modeling techniques.

  • THE SIGNIFICANCE OF HAZARD ENDPOINTS IN QUANTITATIVE RISK ANALYSIS
    1996
    Co-Authors: John B. Cornwell, Jeffrey D. Marx
    Abstract:

    The use of quantitative risk analysis (QRA) by private firms and government agencies has increased the past few years. Typically, QRA techniques are used to obtain a better understanding of the risk posed to people who live or work near hazardous materials facilities, and to aid them in preparing effective emergency response plans. When conducting a QRA, Consequence models are used to predict the size, shape, and orientation of hazard zones that could be created by releases of hazardous materials. The hazards of most interest during the QRA of a petroleum or petrochemical facility are toxic vapor clouds, fire radiation, and blast waves. In order to compute the risk associated with each of these hazards, a common measure of their Consequences must be used. In public risk assessments, the common measure of Consequence is typically the impact on humans exposed to each type of hazard. Therefore, the outer limits of the hazard zones predicted by the Consequence models must be based on a set of Modeling endpoints that are expected to produce identical impacts on humans (e.g., 1% mortality). The endpoints of interest are normally obtained from published probit equations that are appropriate for each hazard being considered. However, for some hazards, several probit equations have been published. For a specific level of Consequence, the available probit equations may calculate widely different endpoints, thus making it difficult to decide which probit equation should be deemed appropriate. This paper compares the results of two QRAs conducted on a hydrocracking unit within a refinery. These QRAs were identical except for the endpoints selected for use in the Consequence models. The individual risk contours and f/N curves generated by the two QRAs are compared to illustrate how the results of a QRA can be affected by the selection of Modeling endpoints. Based on this comparison, the following conclusion is clear: industry and government agencies must agree on the hazard endpoints to be used in a QRA before Consequence Modeling begins or else the conclusions drawn by each group may be quite different.

Tahsin Çetinyokuş - One of the best experts on this subject based on the ideXlab platform.

  • Group Decision Making for Hazard Analysis and Consequence Modelling Software Selection with AHP
    Iranian Journal of Chemistry & Chemical Engineering-international English Edition, 2020
    Co-Authors: Saliha Çetinyokuş, Emre Çalişkan, Erdem Aksakal, Tahsin Çetinyokuş
    Abstract:

    Software evaluation and selection have begun to be addressed as a topic title along with the fact that microcomputers and then personal computers have become widespread and have been used in the operations of businesses. In this study, it was focused on the selection of software for identifying the physical effect distances of the explosion, fire, and toxic emission, which is an important need for industrial institutions containing, using or storing hazardous chemicals. The evaluation and selection of software for the Hazard Analysis and Consequence Modeling (HACM) of potential accidents was studied at first. In means of methodology, questionnaires consisting of original questions were applied to the experts. The results obtained from questionnaires according to the Likert scale, were converted into Analytical Hierarchy Process (AHP) suggestion matrices. In this way, the inconsistency problem in the pairwise comparison matrices was eliminated. As a result, evaluation and selection were made among the HACM software.

  • Hybrid Use of Likert Scale-Based AHP and PROMETHEE Methods for Hazard Analysis and Consequence Modeling (HACM) Software Selection
    International Journal of Information Technology & Decision Making, 2019
    Co-Authors: Emre Çalişkan, Erdem Aksakal, Saliha Çetinyokuş, Tahsin Çetinyokuş
    Abstract:

    Being a decision-making process, software evaluation and selection is complicated, time-consuming, costly and also critical to the success of the project/work/organization. In this study, evaluation and selection of customized software which are used to identify the physical effect (explosion, fire and toxic emission) distances for industrial establishments containing, using or storing hazardous chemicals has been considered. These software are called the “Hazard Analysis and Consequence Modeling” (HACM) software in the literature. This study first prepared Likert scale-based questionnaires which were distributed to Environmental Health and Safety (EHS) professionals to obtain their opinions. Likert scale was used with Analytic Hierarchy Process (AHP) method in the processing of data obtained from questionnaires in order to get over the inconsistency problem of pairwise comparison matrices. The Likert scale-based AHP method was used to determine the weights of the criteria, and Preference Ranking Organization METHod for Enrichment Evaluations (PROMETHEE) method was used to obtain the final ranking. PROMETHEE method was preferred for having the opportunity of evaluating the binary “Yes–No” questions in the solution process. Finally, application results were given to illustrate the proposed method by using the PROMETHEE software “Visual PROMETHEE 1.4.0.0”.

  • hybrid use of likert scale based ahp and promethee methods for hazard analysis and Consequence Modeling hacm software selection
    International Journal of Information Technology and Decision Making, 2019
    Co-Authors: Emre Çalişkan, Erdem Aksakal, Saliha Çetinyokuş, Tahsin Çetinyokuş
    Abstract:

    Being a decision-making process, software evaluation and selection is complicated, time-consuming, costly and also critical to the success of the project/work/organization. In this study, evaluatio...