56,068 research outputs found
Simplified Estimation of Economic Seismic Risk for Buildings
A seismic risk assessment is often performed on behalf of a buyer of
commercial buildings in seismically active regions. One outcome of the assessment is that a probable maximum loss (PML) is computed. PML is of
limited use to real-estate investors as it has no place in a standard financial
analysis and reflects too long a planning period. We introduce an alternative
to PML called probable frequent loss (PFL), defined as the mean loss resulting from shaking with 10% exceedance probability in 5 years. PFL is approximately related to expected annualized loss (EAL) through a site economic hazard coefficient (H) introduced here. PFL and EAL offer three
advantages over PML: (1) meaningful planning period; (2) applicability in financial analysis (making seismic risk a potential market force); and (3) can
be estimated using a single linear structural analysis, via a simplified method
called linear assembly-based vulnerability (LABV) that is presented in this
work. We also present a simple decision-analysis framework for real-estate
investments in seismic regions, accounting for risk aversion. We show that
market risk overwhelms uncertainty in seismic risk, allowing one to consider
only expected consequences in seismic risk. We illustrate using 15 buildings,
including a 7-story nonductile reinforced-concrete moment-frame building in
Van Nuys, California, and 14 buildings from the CUREE-Caltech Woodframe Project
Training of Crisis Mappers and Map Production from Multi-sensor Data: Vernazza Case Study (Cinque Terre National Park, Italy)
This aim of paper is to presents the development of a multidisciplinary project carried out by the cooperation between Politecnico di Torino and ITHACA (Information Technology for Humanitarian Assistance, Cooperation and Action). The goal of the project was the training in geospatial data acquiring and processing for students attending Architecture and Engineering Courses, in order to start up a team of "volunteer mappers". Indeed, the project is aimed to document the environmental and built heritage subject to disaster; the purpose is to improve the capabilities of the actors involved in the activities connected in geospatial data collection, integration and sharing. The proposed area for testing the training activities is the Cinque Terre National Park, registered in the World Heritage List since 1997. The area was affected by flood on the 25th of October 2011. According to other international experiences, the group is expected to be active after emergencies in order to upgrade maps, using data acquired by typical geomatic methods and techniques such as terrestrial and aerial Lidar, close-range and aerial photogrammetry, topographic and GNSS instruments etc.; or by non conventional systems and instruments such us UAV, mobile mapping etc. The ultimate goal is to implement a WebGIS platform to share all the data collected with local authorities and the Civil Protectio
Cyber Attack Surface Mapping For Offensive Security Testing
Security testing consists of automated processes, like Dynamic Application Security Testing (DAST) and Static Application Security Testing (SAST), as well as manual offensive security testing, like Penetration Testing and Red Teaming. This nonautomated testing is frequently time-constrained and difficult to scale. Previous literature suggests that most research is spent in support of improving fully automated processes or in finding specific vulnerabilities, with little time spent improving the interpretation of the scanned attack surface critical to nonautomated testing. In this work, agglomerative hierarchical clustering is used to compress the Internet-facing hosts of 13 representative companies as collected by the Shodan search engine, resulting in an average 89% reduction in attack surface complexity. The work is then extended to map network services and also analyze the characteristics of the Log4Shell security vulnerability and its impact on attack surface mapping. The results highlighted outliers indicative of possible anti-patterns as well as opportunities to improve how testers and tools map the web attack surface. Ultimately the work is extended to compress web attack surfaces based on security relevant features, demonstrating via accuracy measurements not only that this compression is feasible but can also be automated. In the process a framework is created which could be extended in future work to compress other attack surfaces, including physical structures/campuses for physical security testing and even humans for social engineering tests
On the complexity of color-avoiding site and bond percolation
The mathematical analysis of robustness and error-tolerance of complex
networks has been in the center of research interest. On the other hand, little
work has been done when the attack-tolerance of the vertices or edges are not
independent but certain classes of vertices or edges share a mutual
vulnerability. In this study, we consider a graph and we assign colors to the
vertices or edges, where the color-classes correspond to the shared
vulnerabilities. An important problem is to find robustly connected vertex
sets: nodes that remain connected to each other by paths providing any type of
error (i.e. erasing any vertices or edges of the given color). This is also
known as color-avoiding percolation. In this paper, we study various possible
modeling approaches of shared vulnerabilities, we analyze the computational
complexity of finding the robustly (color-avoiding) connected components. We
find that the presented approaches differ significantly regarding their
complexity.Comment: 14 page
Evaluating Drought Vulnerability of Small Community Surface Water Supply Systems in the Midwest
This report presents approaches and data availability for evaluating the drought
vulnerability of small community water supply systems in the Midwest that obtain water from
surface water bodies, such as rivers, streams, natural lakes, and man-made reservoirs. A
description is provided of the various types of surface water sources from which 320 small
community systems in the Midwest, each serving 10,000 or fewer people, obtain their water.
The small community surface water system most commonly obtains its supply from one or two
small impounding reservoirs. However, a substantial number of communities instead obtain
their water from either direct river withdrawals or off-channel storage of water withdrawn from
streams and rivers. Sixty of these 320 small community surface water systems were interviewed
to gather information on the availability of data to determine the drought vulnerability of these
systems. Although hydrologic and physical data exist for evaluating many of these systems,
relatively few of the interviewed system managers could provide such pertinent information.
A summary of selected hydrologic data is provided that can be used to determine the
relative severity of major historical drought periods for various portions of the Midwest. Focus
is given to historical droughts and available data for the southern portion of the Midwest where
most surface water supply systems are located, comprising parts of Kansas, Missouri, Iowa,
Illinois, Indiana, and Ohio. Geographic differences in drought severity are described, as is the
influence of the physical characteristics of a water supply on the “critical” drought duration that
a community must consider.
Basic water budget analyses of water supplies and data needs are presented. Reservoir
capacity measurements and estimates of inflow are the most critical data in reliable assessment
of water supply adequacy. Depending on data availability, estimation of inflows may be
straightforward to highly uncertain. For water supply systems that withdraw directly from a
stream or river, the existence of long-term stream gage data on that river is particularly crucial to
evaluate supply adequacy, and such data for larger streams and rivers are often available. With
impounding reservoirs, which are typically located on smaller streams, data for that stream may
often not exist; however, data from a “surrogate” gage that is considered to be hydrologically
similar are often sufficient to estimate water supply yield. Systems that use off-channel
reservoirs often withdraw water from smaller streams that do not have data for accurate depiction
of their yield, and these systems also appear to be the most vulnerable to severe drought
conditions. Case studies are presented to provide examples of yield calculations and innovative
approaches that selected small communities have undertaken for addressing drought
vulnerability. The role of demand management (drought response and water conservation) in
evaluating drought vulnerability is also presented.
If hydrologic data and basic physical data such as storage capacity are lacking, it may be
difficult for either system managers or experienced professionals to estimate a community
system’s yield and potential drought impacts, particularly for off-channel reservoir and low
channel dam systems. However, managers should attempt to understand the type of drought
period likely to test the adequacy of the available supply and can begin recording basic system
observations, such as daily withdrawal records and reservoir drawdown, in a readily-accessible
form that will be useful for future evaluations.published or submitted for publicationis peer reviewe
Community-Based Health and Exposure Study around Urban Oil Developments in South Los Angeles.
Oilfield-adjacent communities often report symptoms such as headaches and/or asthma. Yet, little data exists on health experiences and exposures in urban environments with oil and gas development. In partnership with Promotoras de Salud (community health workers), we gathered household surveys nearby two oil production sites in Los Angeles. We tested the capacity of low-cost sensors for localized exposure estimates. Bilingual surveys of 205 randomly sampled residences were collected within two 1500 ft. buffer areas (West Adams and University Park) surrounding oil development sites. We used a one-sample proportion test, comparing overall rates from the California Health Interview Survey (CHIS) of Service Planning Area 6 (SPA6) and Los Angeles County for variables of interest such as asthma. Field calibrated low-cost sensors recorded methane emissions. Physician diagnosed asthma rates were reported to be higher within both buffers than in SPA6 or LA County. Asthma prevalence in West Adams but not University Park was significantly higher than in Los Angeles County. Respondents with diagnosed asthma reported rates of emergency room visits in the previous 12 months similar to SPA6. 45% of respondents were unaware of oil development; 63% of residents would not know how to contact local regulatory authorities. Residents often seek information about their health and site-related activities. Low-cost sensors may be useful in highlighting differences between sites or recording larger emission events and can provide localized data alongside resident-reported symptoms. Regulatory officials should help clarify information to the community on methods for reporting health symptoms. Our community-based participatory research (CBPR) partnership supports efforts to answer community questions as residents seek a safety buffer between sensitive land uses and active oil development
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