The impact of toxicity dose-response relationships on quantitative risk analysis results

Purpose The purpose of this paper is to present a fault tree (FT)-based approach for quantitative risk analysis in the construction industry that can take into account both objective and subjective uncertainties. Design/methodology/approach In this research, the identified basic events (BEs) are first categorized based on the availability of historical data into probabilistic and possibilistic. The probabilistic and possibilistic events are represented by probability distributions and fuzzy numbers, respectively. Hybrid uncertainty analysis is then performed through a combination of Monte Carlo simulation and fuzzy set theory. The probability of occurrence of the top event is finally calculated using the proposed FT-based hybrid uncertainty analysis method. Findings The efficiency of the proposed method is demonstrated by implementing in a real steel structure project. A quantitative risk assessment is performed for weld cracks, taking into account of both types of uncertainties. An importance analysis is finally performed to evaluate the contribution of each BE to the probability of occurrence of weld cracks and adopt appropriate response strategies. Research limitations/implications In this research, the impact of objective (aleatory) dependence between the occurrences of different BEs and subjective (epistemic) dependence between estimates of the epistemically uncertain probabilities of some BEs are not considered. Moreover, there exist limitations to the application of fuzzy set rules, which were used for aggregating experts’ opinions and ranking purposes of the BEs in the FT model. These limitations can be investigated through further research. Originality/value It is believed that the proposed hybrid uncertainty analysis method presents a robust and powerful tool for quantitative risk analysis, as both types of uncertainties are taken into account appropriately.

Download Full-text

Designing Risk Qualitative Assessment on Fiber Optic Instalation Project in Indonesia

International Journal of Innovation in Enterprise System ◽

10.25124/ijies.v2i01.55 ◽

2018 ◽

Vol 2 (01) ◽

Author(s):

Devi Pratami

Keyword(s):

Risk Assessment ◽

Risk Analysis ◽

Fiber Optic ◽

Qualitative Assessment ◽

Quality And Safety ◽

Project Implementation ◽

Cost Impact ◽

Implementation Assessment ◽

The Impact ◽

Impact Cost

A project always has risks that can lead to project failure. In the project, a risk analysis is required to provide an evaluation for the project to proceed as planned. In the event of inadequate planning and ineffective control, it will result in irregularities identified as a risk to the project. This study aims to analyze the qualitative risk on Fiber Optic Installaion project in Sukabumi, West Java, Indonesia. In addition, risk assessment is undertaken on project implementation. Assessment of risk using the impact and probability to measure the impact of risk occurrence. The impacts are more detailed by classified by time impact, cost impact, quality impact, safety and security impact, proximity. The result is there are 36 risk that may occur and mostly risks are associaated by quality and safety&security impact.

Download Full-text

A Monte Carlo Determination of Dose and Range Uncertainties for Preclinical Studies with a Proton Beam

Cancers ◽

10.3390/cancers13081889 ◽

2021 ◽

Vol 13 (8) ◽

pp. 1889

Author(s):

Arthur Bongrand ◽

Charbel Koumeir ◽

Daphnée Villoing ◽

Arnaud Guertin ◽

Ferid Haddad ◽

...

Keyword(s):

Monte Carlo ◽

Monte Carlo Simulations ◽

Proton Beam ◽

Dose Response ◽

Small Animal ◽

Absorbed Dose ◽

Normal Tissue Damage ◽

Dose Homogeneity ◽

And Control ◽

The Impact

Proton therapy (PRT) is an irradiation technique that aims at limiting normal tissue damage while maintaining the tumor response. To study its specificities, the ARRONAX cyclotron is currently developing a preclinical structure compatible with biological experiments. A prerequisite is to identify and control uncertainties on the ARRONAX beamline, which can lead to significant biases in the observed biological results and dose–response relationships, as for any facility. This paper summarizes and quantifies the impact of uncertainty on proton range, absorbed dose, and dose homogeneity in a preclinical context of cell or small animal irradiation on the Bragg curve, using Monte Carlo simulations. All possible sources of uncertainty were investigated and discussed independently. Those with a significant impact were identified, and protocols were established to reduce their consequences. Overall, the uncertainties evaluated were similar to those from clinical practice and are considered compatible with the performance of radiobiological experiments, as well as the study of dose–response relationships on this proton beam. Another conclusion of this study is that Monte Carlo simulations can be used to help build preclinical lines in other setups.

Download Full-text

Resilience of Heterogeneous Aquifers Evaluated from Different Dose-Response Models of Bisphenol A

Proceedings ◽

10.3390/ecws-4-06423 ◽

2019 ◽

Vol 48 (1) ◽

pp. 21

Author(s):

Jinwoo Im ◽

Calogero B. Rizzo ◽

Felipe P. J. de Barros

Keyword(s):

Bisphenol A ◽

Human Health ◽

Health Risks ◽

Dose Response ◽

Emerging Contaminants ◽

Contaminated Sites ◽

Heterogeneous Structure ◽

Control Plane ◽

Human Health Risks ◽

The Impact

With the growing concerns over emerging contaminants in indirect potable reuse (IPR) applications, we investigate the impact on human health risk of emerging contaminants introduced into groundwater. Some emerging contaminants have potential endocrine-related health effects at a specific exposure range that is much lower than current guidelines. We start by analyzing Bisphenol A (BPA), which is one of the frequently detected emerging contaminants in groundwater. The objective of this study is to understand how the non-trivial toxicity of BPA affects the estimation of human health risks and, consequentially, aquifer resilience. Based on our results, we aim to provide indications on how to improve water resources management in BPA contaminated sites. We use numerical methods to model BPA contamination of a three-dimensional aquifer, and human health risks and aquifer resilience are estimated at a control plane representing an environmentally sensitive target. A Monte Carlo simulation is conducted to compute uncertainty associated with two levels of heterogeneity. In order to evaluate health risks due to BPA, two types of Dose-Response (DR) models are considered: the monotonic DR model for general exposure and the non-monotonic DR model for prenatal/postnatal exposure. The aquifer resilience is defined as the capacity to recover the state where groundwater is considered potable (i.e., negligible health risks due to BPA). When using the non-monotonic DR model, computational results indicate that the aquifer resilience reduces and its uncertainty increases as the aquifer heterogeneity increases. On the other hand, the aquifer resilience considering the monotonic DR model enhances, and its uncertainty increases relatively smaller than the one considering the non-monotonic DR model. In addition, the variability of the aquifer resilience is controlled by the residence time of the BPA plumes at the control plane, which is related to the volumetric flow rate at the front side of the contamination source. Finally, the decision-making strategy for BPA contaminated sites should be established in accordance with the heterogeneous structure of aquifer and land uses that determines which DR model of BPA is more important in estimating the aquifer resilience.

Download Full-text