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排序方式: 共有335条查询结果,搜索用时 15 毫秒
61.
Asaf Shabtai Author Vitae Uri Kanonov Author Vitae Author Vitae 《Journal of Systems and Software》2010,83(8):1524-1537
In this paper, a new approach for detecting previously unencountered malware targeting mobile device is proposed. In the proposed approach, time-stamped security data is continuously monitored within the target mobile device (i.e., smartphones, PDAs) and then processed by the knowledge-based temporal abstraction (KBTA) methodology. Using KBTA, continuously measured data (e.g., the number of sent SMSs) and events (e.g., software installation) are integrated with a mobile device security domain knowledge-base (i.e., an ontology for abstracting meaningful patterns from raw, time-oriented security data), to create higher level, time-oriented concepts and patterns, also known as temporal abstractions. Automatically-generated temporal abstractions are then monitored to detect suspicious temporal patterns and to issue an alert. These patterns are compatible with a set of predefined classes of malware as defined by a security expert (or the owner) employing a set of time and value constraints. The goal is to identify malicious behavior that other defensive technologies (e.g., antivirus or firewall) failed to detect. Since the abstraction derivation process is complex, the KBTA method was adapted for mobile devices that are limited in resources (i.e., CPU, memory, battery). To evaluate the proposed modified KBTA method a lightweight host-based intrusion detection system (HIDS), combined with central management capabilities for Android-based mobile phones, was developed. Evaluation results demonstrated the effectiveness of the new approach in detecting malicious applications on mobile devices (detection rate above 94% in most scenarios) and the feasibility of running such a system on mobile devices (CPU consumption was 3% on average). 相似文献
62.
During a fire at a power plant located in the coastal plain of Israel, PCBs were released to the atmosphere from a ruptured transformer. Since PCBs are probably carcinogenic to humans, this study was performed in order to assess the environmental contamination by PCBs via the atmospheric pathway and the need for remediation measures. The release conditions and the meteorological conditions which prevailed during the fire were analyzed. This provided the input to a Gaussian dispersion model used to estimate the downwind-contaminated sector as well as the location of the maximal concentration within this sector. A sampling plan was then devised and vegetation collected within this sector was analyzed for PCBs. A methodology was developed to convert PCB concentrations in vegetation to concentrations in the atmosphere. It allowed a reconstitution of the PCB source term to the atmosphere from the vegetation measurements. The PCB concentrations were found to be lower than the USEPA decontamination standards. Remediation measures were not needed beyond the plant fence. 相似文献
63.
Richard Le Heron Glen W. Atkinson Henry Teune Greg Mason Henk Voogd Brenda J. Moscove Patricia Gober Thomas A. Reiner Richard F. Curtis Stephen F. Seninger W. W. Hall Jr. John E. Keith M. Van Naelten R. W. Keyes John Huttman Robert B. Weeden Clarence G. Ray Steven E. Daniels F. Larry Leistritz Patrizia Spinetti Peter D. Beaulieu F. J. Potgieter David L. Barkley Charles A. Berry Jean E. Weber Wieslaw Rozlucki Jesse Burkhead John R. Ottensmann Noel D. Uri Erlet Cater J. Barry Riddell Ernesto Quintanilla John F. McDonald Jon R. Miller Stan Czamanski 《The Annals of Regional Science》1986,20(1):87-144
64.
Safinya CR Ewert K Ahmad A Evans HM Raviv U Needleman DJ Lin AJ Slack NL George C Samuel CE 《Philosophical transactions. Series A, Mathematical, physical, and engineering sciences》2006,364(1847):2573-2596
At present, there is an unprecedented level of interest in the properties and structures of complexes consisting of DNA mixed with oppositely charged cationic liposomes (CLs). The interest arises because the complexes mimic natural viruses as chemical carriers of DNA into cells in worldwide human gene therapy clinical trials. However, since our understanding of the mechanisms of action of CL-DNA complexes interacting with cells remains poor, significant additional insights and discoveries will be required before the development of efficient chemical carriers suitable for long-term therapeutic applications. Recent studies describe synchrotron X-ray diffraction, which has revealed the liquid crystalline nature of CL-DNA complexes, and three-dimensional laser-scanning confocal microscopy, which reveals CL-DNA pathways and interactions with cells. The importance of the liquid crystalline structures in biological function is revealed in the application of these modern techniques in combination with functional transfection efficiency measurements, which shows that the mechanism of gene release from complexes in the cell cytoplasm is dependent on their precise liquid crystalline nature and the physical and chemical parameters (for example, the membrane charge density) of the complexes. In [section sign] 5, we describe some recent new results aimed at developing bionanotube vectors for gene delivery. 相似文献
65.
This paper details the Box-Jenkins approach to forecasting time series and applies it to short-term natural gas marketed production and crude petroleum production in the United States. After establishing the efficacy of the approach for forecasting the two series of interest, monthly forecasts for 1978 are made. The results indicate that natural gas production in 1978 will increase by 2·8 per cent over the 1977 level while crude petroleum production will fall by 4·0 per cent. 相似文献
66.
67.
A. N. Spector Lay James Gibson Ashok K. Dutt William F. Hyde Paul B. Sherman Hans-Jurg Buttler Bernard Malamud Robert N. Anderson M. Penouil R. W. Keyes Lee R. McPheters William R. Eadington Kurt Puchinger Arthur E. Kartman Charles E. Starnes J. Barry Riddell Erick Sheppard Leon E. Zonn Craig Moore Neil S. Grigg K. Shimizu Daniel A. Griffith Noel D. Uri Micheal Ross Jack E. Adams Robert G. Fletcher Karol J. Krotki Peter D. Beaulieu Fred E. Case W. Edwin Derrick Barry D. Solomon Debnath Mookherjee John E. Keith Yuk Lee Andrew A. Dzurik W. W. Hall Jr. Lloyd W. Klemke Ted J. Adamczyk 《The Annals of Regional Science》1981,15(3):82-146
68.
Uri Avin Robert Goodspeed 《Journal of the American Planning Association. American Planning Association》2020,86(4):403-416
AbstractProblem, research strategy, and findings: Despite growing interest by practitioners in using exploratory scenarios within urban planning practice, there are few detailed guidelines for how to do this. Through the discussion of five case examples, we illustrate different approaches to linking exploratory scenarios to different planning contexts. We conclude by observing that to directly inform a plan, regardless of the specific approach taken, exploratory scenarios in urban planning must incorporate stakeholder values and not only rely on expert judgment and analysis.Takeaway for practice: Exploratory scenarios are effective for analyzing uncertainty within a planning process. However, exploratory scenarios can be incorporated into planning practice in different ways, ranging from workshops among experts that aim to cultivate general learning to complex projects that result in highly detailed scenarios and recommendations for plans. Practitioners can draw on the cases we present to inspire planning methods for particular projects, taking into account specific contexts and goals. 相似文献
69.
Synchronized External Pulsation for Improved Tolerance to Acceleration Stress: Model Studies and Preliminary Experiments 总被引:1,自引:0,他引:1
Moore Thomas W. Jaron Dov Chu Chia-Lin Dinnar Uri Hrebien Leonid White Michael J. Hendler Edwin Dubin Stephen 《IEEE transactions on bio-medical engineering》1985,(2):158-165
Synchronized external pulsation is proposed as a method to improve tolerance to acceleration stress. This technique uses a modified anti-G suit which is pressurized and depressurized synchronously with the heart cycle. The feasibility of the procedure has been studied using a computer model of the cardiovascular system which includes the effects of Gz stress, and contains simulations of baroreceptor control of heart rate and venous tone. Model predictions indicate that for unprotected subjects, carotid pressure at eye level (ophthalmic artery pressure) decreases to 20 mmHg (beginning of central light loss) at approximately +3.6 Gz. Applying standard anti-G suit pressure to the model increases this level to 5.3 Gz. When synchronized external pulsation of 2 psi is superimposed on the standard anti-G suit pressure, the tolerance to acceleration stress is further augmented by at least 0.9 G above the protection afforded by the standard anti-G suit alone. A set of preliminary experiments on human subjects to test the feasibility of using the technique in the high-G environment has also been carried out. The results under various protection modes compare favorably to the model predictions. Our results suggest that the computer model presented here is a useful tool for studying cardiovascular responses under +GZ stress. It also indicates that using synchronized external pulsation pressure superimposed on the standard anti-G suit pressure may offer extra protection to acceleration stress. 相似文献
70.
Noel D. Uri 《国际能源研究杂志》1993,17(8):747-758
This study is concerned with the assessing the impact that inaccuracy in the measurement of the dependent variable and one or more of the independent variables has on the estimate of the price elasticity of demand for diesel fuel by farmers in the United States. Two diagnostics – the regression coefficient bounds and the bias correction factor — are introduced to assess the effect that such measurement errors have on the estimated coefficients of the diesel fuel demand relationship. 相似文献