30 research outputs found

    Optimizing resilience decision-support for natural gas networks under uncertainty

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    2019 Summer.Includes bibliographical references.Community resilience in the aftermath of a hazard requires the functionality of complex, interdependent infrastructure systems become operational in a timely manner to support social and economic institutions. In the context of risk management and community resilience, critical decisions should be made not only in the aftermath of a disaster in order to immediately respond to the destructive event and properly repair the damage, but preventive decisions should to be made in order to mitigate the adverse impacts of hazards prior to their occurrence. This involves significant uncertainty about the basic notion of the hazard itself, and usually involves mitigation strategies such as strengthening components or preparing required resources for post-event repairs. In essence, instances of risk management problems that encourage a framework for coupled decisions before and after events include modeling how to allocate resources before the disruptive event so as to maximize the efficiency for their distribution to repair in the aftermath of the event, and how to determine which network components require preventive investments in order to enhance their performance in case of an event. In this dissertation, a methodology is presented for optimal decision making for resilience assessment, seismic risk mitigation, and recovery of natural gas networks, taking into account their interdependency with some of the other systems within the community. In this regard, the natural gas and electric power networks of a virtual community were modeled with enough detail such that it enables assessment of natural gas network supply at the community level. The effect of the industrial makeup of a community on its natural gas recovery following an earthquake, as well as the effect of replacing conventional steel pipes with ductile HDPE pipelines as an effective mitigation strategy against seismic hazard are investigated. In addition, a multi objective optimization framework that integrates probabilistic seismic risk assessment of coupled infrastructure systems and evolutionary algorithms is proposed in order to determine cost-optimal decisions before and after a seismic event, with the objective of making the natural gas network recover more rapidly, and thus the community more resilient. Including bi-directional interdependencies between the natural gas and electric power network, strategic decisions are pursued regarding which distribution pipelines in the gas network should be retrofitted under budget constraints, with the objectives to minimizing the number of people without natural gas in the residential sector and business losses due to the lack of natural gas in non-residential sectors. Monte Carlo Simulation (MCS) is used in order to propagate uncertainties and Probabilistic Seismic Hazard Assessment (PSHA) is adopted in order to capture uncertainties in the seismic hazard with an approach to preserve spatial correlation. A non-dominated sorting genetic algorithm (NSGA-II) approach is utilized to solve the multi-objective optimization problem under study. The results prove the potential of the developed methodology to provide risk-informed decision support, while being able to deal with large-scale, interdependent complex infrastructure considering probabilistic seismic hazard scenarios

    Spotting Keywords in Offline Handwritten Documents Using Hausdorff Edit Distance

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    Keyword spotting has become a crucial topic in handwritten document recognition, by enabling content-based retrieval of scanned documents using search terms. With a query keyword, one can search and index the digitized handwriting which in turn facilitates understanding of manuscripts. Common automated techniques address the keyword spotting problem through statistical representations. Structural representations such as graphs apprehend the complex structure of handwriting. However, they are rarely used, particularly for keyword spotting techniques, due to high computational costs. The graph edit distance, a powerful and versatile method for matching any type of labeled graph, has exponential time complexity to calculate the similarities of graphs. Hence, the use of graph edit distance is constrained to small size graphs. The recently developed Hausdorff edit distance algorithm approximates the graph edit distance with quadratic time complexity by efficiently matching local substructures. This dissertation speculates using Hausdorff edit distance could be a promising alternative to other template-based keyword spotting approaches in term of computational time and accuracy. Accordingly, the core contribution of this thesis is investigation and development of a graph-based keyword spotting technique based on the Hausdorff edit distance algorithm. The high representational power of graphs combined with the efficiency of the Hausdorff edit distance for graph matching achieves remarkable speedup as well as accuracy. In a comprehensive experimental evaluation, we demonstrate the solid performance of the proposed graph-based method when compared with state of the art, both, concerning precision and speed. The second contribution of this thesis is a keyword spotting technique which incorporates dynamic time warping and Hausdorff edit distance approaches. The structural representation of graph-based approach combined with statistical geometric features representation compliments each other in order to provide a more accurate system. The proposed system has been extensively evaluated with four types of handwriting graphs and geometric features vectors on benchmark datasets. The experiments demonstrate a performance boost in which outperforms individual systems

    Depression and its Main Determinants Among Iranian Operating Room Personnel: A Systematic Review and Meta-Analysis

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    Background: Most nurses, especially operating room personnel, seems to be more likely to be affected by mood disorders than other social strata. The present study attempted to systematically review the prevalence of depression and its main determinants among operating room personnel in Iran.Methods: The method of this systematic review is documenting in a published protocol in the International Prospective Register of Systematic Reviews (PROSPERO) and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) checklist. After this massive search, titles and abstracts of retrieved documents have screened and all irrelevant articles excluded. Two reviewers screened the documents and selected all relevant studies and assessed included articles separately.Results: Totally, 12 citations found in the initial literature search where four citations excluded, as they did not meet the inclusion criteria. The final number of studies available for analysis was 12 including a total of 373 operating room personnel (86 men and 287 women, mean the age of 27.71 years ranged from 20 to 36 years). The pooled prevalence of depression among operating room personnel was estimated to be 45.3%. In this regard, 27.0% of personnel suffered from severe depression. A significant heterogeneity found in the overall analysis of the overall prevalence of depression and its severe pattern.Conclusion: A notable number of operating room personnel in Iran suffer from depression even in its severe condition emphasizing the importance of the managerial approach to minimize its adverse effects on their performance as well as to improve their quality of life

    Bioassay Screening of the Essential Oil and Various Extracts of Fruits of Heracleum persicum Desf. and Rhizomes of Zingiber officinale Rosc. using Brine Shrimp Cytotoxicity Assay

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    In the present work, the bioassay screening of the essential oil and various extracts of two plants including fruits of Heracleum persicum Desf. and rhizomes of Zingiber officinale Rosc. have been studied with brine shrimp test. There is only one report about cytotoxicity of H. sphondylium in literature and so H. persicum has been used as second selection. At first essentials oil and various extracts of two plants including petroleum ether, chloroform, methanol, ether and aqueous were provided. Then, different concentrations of them were prepared. These fractions were evaluated for toxicity using Brine Shrimp Lethality assay (BSL). Each of fractions was assessed by two methods of disk and solution. Survivors were counted after 24 h. These data were processed in Probit-analysis program to estimate LC50 values (the concentration at which 50% lethality was observed) with 95% confidence intervals for statistically significant comparisons of potencies. In disc method, methanol extract of Z. officinale (LC50=28.3134 μg/ml) showed the most activity in comparison with positive standard of potassium dichromate (LC50=23.2893 μg/ml); but in solution method, essential oil of H. persicum ( LC50=0.0071 μl/ml) was the most active fraction in comparison with potassium dichromate (LC50=27.7528 μg/ml). Totally, among tested fractions, essential oil of the H. persicum has been exhibited the most cytotoxicity. The essential oil of H. persicum was analyzed by GC-MS. The major constituents were hexyl butyrate and octyl acetate

    Androgen-induced cerebral venous sinus thrombosis in a young body builder: case report

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    BACKGROUND: Cerebral venous sinus thrombosis is an infrequent disease with a variety of causes. Pregnancy, puerperium, contraceptive pills and intracranial infections are the most common causes. The patient may present with headache, focal neurological deficits and seizures. The clinical outcome is highly variable and treatment with heparin is advised. CASE PRESENTATION: The patient is a 22 year old male who presented with headache, repeated vomiting and papilledema. He was a bodybuilder doing exercise since 5 years ago, who had used nandrolone decaonoate 25 milligrams intramuscularly during the previous 5 months. Brain MRI and MRV showed superior sagital and transverse sinus thrombosis and extensive investigations did not reveal any known cause. CONCLUSIONS: We suggested that androgen was the predisposing factor in our patient. Androgens may increase coagulation factors or platelet activity and cause arterial or venous thrombosis. As athletes may hide using androgens it should be considered as a predisposing factor for thrombotic events in such patients

    Indoor environment assessment of special wards of educational hospitals for the detection of fungal contamination sources: A multi-center study (2019-2021)

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    Background and Purpose: The hospital environment was reported as a real habitat for different microorganisms, especially mold fungi. On the other hand, these opportunistic fungi were considered hospital-acquired mold infections in patients with weak immune status. Therefore, this multi-center study aimed to evaluate 23 hospitals in 18 provinces of Iran for fungal contamination sources.Materials and Methods: In total, 43 opened Petri plates and 213 surface samples were collected throughout different wards of 23 hospitals. All collected samples were inoculated into Sabouraud Dextrose Agar containing Chloramphenicol (SC), and the plates were then incubated at 27-30ºC for 7-14 days.Results: A total of 210 fungal colonies from equipment (162, 77.1%) and air (48,22.9%) were identified. The most predominant isolated genus was Aspergillus (47.5%),followed by Rhizopus (14.2%), Mucor (11.7%), and Cladosporium (9.2%). Aspergillus(39.5%), Cladosporium (16.6%), as well as Penicillium and Sterile hyphae (10.4% each), were the most isolates from the air samples. Moreover, intensive care units (38.5%) and operating rooms (21.9%) had the highest number of isolated fungal colonies. Out of 256 collected samples from equipment and air, 163 (63.7%) were positive for fungal growth.The rate of fungal contamination in instrument and air samples was 128/213 (60.1%) and 35/43 (81.2%), respectively. Among the isolated species of Aspergillus, A. flavus complex (38/96, 39.6%), A. niger complex (31/96, 32.3%), and A. fumigatus complex (15/96, 15.6%) were the commonest species.Conclusion: According to our findings, in addition to air, equipment and instrument should be considered among the significant sources of fungal contamination in the indoor environment of hospitals. Airborne fungi, Hospital, Indoor air, Equipment, Sources of fungal contamination in the indoor environment of hospitals

    PROCJENA I UPRAVLJANJE SIGURNOSNIM RIZIKOM UPORABOM HIJERARHIJSKE ANALIZE NEIZRAVNOGA SKUPA PODATAKA TIPA 1 I 2, PRIMJER PODZEMNOGA RUDNIKA KROMITA FARYAB

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    There is a high rate of casualty among miners in the world every year. One way to reduce accidents and increase safety in mines is to use the risk management process to identify and respond to major hazards in mines. The present study is an attempt to investigate the assessment and management of safety risks in Faryab chromite underground mines. In this paper, the method of AHP in type-1 and type-2 fuzzy sets is used for risk assessment. Upon studying two underground mines of Faryab chromite (Makran and Nemat), 45 hazards were divided into 9 groups, among which 7 main risks were eventually identified. The risk assessment showed that the most important hazards in the Nemat underground mine are the required airflow, the lack of proper scaling and post-blast scaling. Similarly, the assessment of hazards in the Makran underground mine showed that post-blast scaling, absence of proper scaling, and proper ventilation of dust, are the most important hazards. Finally, after detecting the causes of the accidents, based on the records of accidents at the mine safety, health, and environmental unit, technical personnel’s descriptions, and similar risk projects, proper responses are prepared for each group of hazards.Godišnja stopa smrtnosti rudara u svijetu vrlo je visoka. Jedan od načina smanjivanja rizika, odnosno povećanja sigurnosti rudarenja, jest upravljanje takvim rizikom i prepoznavanje glavnih opasnosti. U radu je prikazano istraživanje takve procjene u podzemnome rudniku kromita Faryab. U ocjenjivanju rizika uporabljene su metode AHP-a na neizravnim skupovima podataka tipa 1 i 2. Izučena su dva podzemna radilišta u spomenutome rudniku (Makran i Nemat). 45 opasnosti podijeljeno je u 9 skupina sa 7 temeljnih rizika. Najveća opasnost na radilištu Nemat jest protok zraka te ocjena primjerenoga izvlačenja jalovine, posebice nakon miniranja. Vrlo slična procjena načinjena je i za radilište Makran. Nakon otkrivanja uzroka nesreća, na temelju evidencije nesreća u jedinici za sigurnost, zdravlje i zaštitu okoliša, opisa tehničkoga osoblja i sličnih projekata rizika, pripremaju se odgovarajuće reakcije za svaku skupinu opasnosti

    The New Concession Agreements and the Interests of Oil Producer Countries:With Specific Reference to Ownership of the Oil, Host State’s Control and Management and the Fiscal Regime of the Agreements

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    The main purpose of this Article is to examine the new concession agreements, and to compare relevant modifications and changes with the traditional concessions, they have undergone. To this end three subjects are examined: The ownership of the oil, governmental control and management of the oil production and the fiscal regime of the agreements in question. In an attempt to deal with the first issue, the study has differentiated between two situations: A situation where the oil is still in place and has not yet been exploited. In this case, as is with other new oil contracts, under the new concessions the government still owns the oil. The other situation is when the oil is produced and is technically speaking at the wellhead, in which point the concessionaire acquires the ownership of the produced oil; while the host government retains ownership of resources that remains in the subsoil. This salient feature of the concessions (both the new and the traditional ones) makes it distinguishable from other petroleum contracts. For instance, in a production sharing agreement a percentage of the ownership of product is conveyed to the contractor at the exporting point, whereas, under a service contract, the contractor does not acquire any ownership rights over the oil production. With respect to governmental control and management, we have found that due to awareness of the host governments of the benefits of their natural resources, they were able to obtain the right of control and management of the exploration and exploitation of their resources , which found expression not only in the new concessions but also in such agreements as service and production sharing contracts. In practice, however, because of the paucity of the requisite skill and technology for exploration and exploitation operations, they have not been able to achieve such a purpose. As regards the question of the fiscal regime, where such matters as taxation, royalty and bonus were examined, we found that all changes made, were in favour of the host countries: except, however, where the risk of failure to explore successfully was very high; in which case more attractive and incentive rewards were granted to the concessionaire

    Interfacial modification to optimize stainless steel photoanode design for flexible dye sensitized solar cells: an experimental and numerical modeling approach

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    In the present research, we report fabrication, experimental characterization and theoretical analysis of semi and full flexible dye sensitized solar cells (DSSCs) manufactured on the basis of bare and roughened stainless steel type 304 (SS304) substrates. The morphological, optical and electrical characterizations confirm the advantage of roughened SS304 over bare and even common transparent conducting oxides (TCOs). A significant enhancement of about 51% in power conversion efficiency is obtained for flexible device (5.51%) based on roughened SS304 substrate compared to the bare SS304. The effect of roughening the SS304 substrates on electrical transport characteristics is also investigated by means of numerical modeling with regard to metal-semiconductor and interfacial resistance arising from the metallic substrate and nanocrystalline semiconductor contact. The numerical modeling results provide a reliable theoretical backbone to be combined with experimental implications. It highlights the stronger effect of series resistance compared to schottky barrier in lowering the fill factor of the SS304-based DSSCs. The findings of the present study nominate roughened SS304 as a promising replacement for conventional DSSCs substrates as well as introducing a highly accurate modeling framework to design and diagnose treated metallic or non-metallic based DSSCs
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