The Experts below are selected from a list of 48 Experts worldwide ranked by ideXlab platform
Wushao Wen - One of the best experts on this subject based on the ideXlab platform.
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ICAIC (4) - An OTP-Based Mechanism for Defending Application Layer DDoS Attacks
Communications in Computer and Information Science, 2011Co-Authors: Wushao Wen, Qin CenAbstract:In this paper, we present the design and implementation of OTP-DEF, a kernel extension to protect web servers against application layer DDoS Attacks. OTP-DEF provides authentication by using OTP-based tests, which is different from other systems that use graphical tests. First of all, according to the load of web server, an OTP-DEF web server should fall into one of three following modes: normal, Suspected Attack or confirmed Attack mode, and the OTP-DEF authentication mechanism shall only be activated when web server is in Suspected Attack mode. Secondly, we use OTP as our puzzle, which can automatically change at the certain time interval. It makes our proposal can defend socially-engineered Attack, copy Attacks, replay Attacks and Brute-Force Attack. Thirdly, OTP-DEF uses an intermediate stage to identify the IP addresses that ignore the test, and persistently bombard the server with requests despite repeated failures at solving the puzzles. These machines are zombies because their intent is to congest the server. Once these machines are identified, OTP-DEF blocks their requests, turns the tests off, and allows access to legitimate users who are unable or unwilling to solve tests. Finally, OTP-DEF requires no modifications to client software.
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A Defensive OTP-Based Mechanism against Application Layer DDoS Attacks
Key Engineering Materials, 2011Co-Authors: Wushao WenAbstract:In this paper, we present the design and implementation of OTP-DEF, a kernel extension to protect web servers against application layer DDoS Attacks. OTP-DEF provides authentication by using OTP-based tests, which is different from other systems that use graphical tests. First of all, according to the load of web server, an OTP-DEF web-server should fall into one of three following modes: normal, Suspected Attack or confirmed Attack mode, and the OTP-DEF authentication mechanism shall only be activated when web-server is in Suspected Attack mode. Secondly, we use OTP as our puzzle, which can automatically change at the certain time interval. It makes our proposal can defend socially-engineered Attack, copy Attacks, replay Attacks and Brute-Force Attack. Thirdly, OTP-DEF uses an intermediate stage to identify the IP addresses that ignore the test, and persistently bombard the server with requests despite repeated failures at solving the puzzles. These machines are zombies because their intent is to congest the server. Once these machines are identified, OTP-DEF blocks their requests, turns the tests off, and allows access to legitimate users who are unable or unwilling to solve tests. Finally, OTP-DEF requires no modifications to client software.
Qin Cen - One of the best experts on this subject based on the ideXlab platform.
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ICAIC (4) - An OTP-Based Mechanism for Defending Application Layer DDoS Attacks
Communications in Computer and Information Science, 2011Co-Authors: Wushao Wen, Qin CenAbstract:In this paper, we present the design and implementation of OTP-DEF, a kernel extension to protect web servers against application layer DDoS Attacks. OTP-DEF provides authentication by using OTP-based tests, which is different from other systems that use graphical tests. First of all, according to the load of web server, an OTP-DEF web server should fall into one of three following modes: normal, Suspected Attack or confirmed Attack mode, and the OTP-DEF authentication mechanism shall only be activated when web server is in Suspected Attack mode. Secondly, we use OTP as our puzzle, which can automatically change at the certain time interval. It makes our proposal can defend socially-engineered Attack, copy Attacks, replay Attacks and Brute-Force Attack. Thirdly, OTP-DEF uses an intermediate stage to identify the IP addresses that ignore the test, and persistently bombard the server with requests despite repeated failures at solving the puzzles. These machines are zombies because their intent is to congest the server. Once these machines are identified, OTP-DEF blocks their requests, turns the tests off, and allows access to legitimate users who are unable or unwilling to solve tests. Finally, OTP-DEF requires no modifications to client software.
Åsa Langefors - One of the best experts on this subject based on the ideXlab platform.
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Building public trust in compensation programs through accuracy assessments of damage verification protocols
Biological Conservation, 2017Co-Authors: José Vicente López-bao, Jens Frank, Linn Svensson, Mikael Åkesson, Åsa LangeforsAbstract:Reliable verification of damage claims is fundamental to create public trust in the legitimacy of compensation programs, and avoid fraud and moral hazards. However, after decades of using this tool, transparency in verification processes and availability of quantitative information on the accuracy and misidentification rates are unresolved issues. Accurate rules overcome several challenges facing compensation programs worldwide, such as the difficulty of proving claims, lack of compensation or insufficiency of community support. Here, we tested the accuracy of the verification protocol of damage claims used in Sweden for large carnivore depredations on sheep. In Sweden, verifiers (who will determine if a livestock owner is compensated or not after a Suspected Attack) uses rules grounded on typical bite marks from each predator species on animal carcasses. Contrasted with DNA salivary analysis, verifiers correctly identified wolf and lynx as the culprit species in 86% (n = 57) and 91% (n = 11) of cases tested, respectively, and the overall accuracy in identifying a predation event was 94%. We believe that rigorous tests of current damage verification protocols are essential to show people the frequency that predation results in compensation, as well as how often other causes of livestock death or injury are erroneously interpreted as being inflicted by large carnivores. The use of DNA salivary analysis to test the accuracy of damage verification protocols is transferable to any livestock-carnivore conflict scenario worldwide, as well as to other wildlife, such as ungulates browsing on forest plantations and crops
Hong Jia-ju - One of the best experts on this subject based on the ideXlab platform.
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Hadoop DDoS Attack detection based on OC-SVM
Journal of Henan University of Urban Construction, 2014Co-Authors: Hong Jia-juAbstract:DDoS has been a major threat to the Internet. It has the characteristics of simple Attack method,destructiveness and untraceable. Research and application of cloud computing is being carried out. The Hadoop,as mainstream platform of cloud computing,faces the same serious threats of DDoS Attack. Thus a new Hadoop DDoS distributed detection system based on one class SVM classification algorithm is proposed in this article.The mechanism of active learning and Suspected Attack verification are used in the new system,which can update the training set in real time,reduce the false positive rate and false negative rate effectively by using this method. It shows that the system has better classification accuracy,low false positive rate and false negative rate in experimental results.
Timothy J. Garrett - One of the best experts on this subject based on the ideXlab platform.
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Detection of Chemical Weapon Nerve Agents in Bone by Liquid Chromatography–Mass Spectrometry
Journal of analytical toxicology, 2020Co-Authors: Katie M. Rubin, Bruce A. Goldberger, Timothy J. GarrettAbstract:A recently proposed model for the incorporation of xenobiotics of forensic interest into the human skeleton suggests nerve agent metabolites may incorporate into bone at relatively elevated concentrations based on their unique chemical properties. To test the hypothesis that nerve agent metabolites interact with bone, methods for the extraction, isolation and semi-quantitative detection of nerve agent metabolites (MPA, EMPA, IMPA, iBuMPA, CMPA and PMPA, corresponding to the nerve agents VX, Russian VX, sarin, cyclosarin and soman, respectively) from osseous tissue were developed using liquid chromatography-mass spectrometry with both quadrupole time-of-flight and triple quadrupole (QqQ) instruments. The optimized methods were validated on the QqQ instrument. Despite high ion suppression, the achieved limits of detection (5-20 pg/g for four analytes; 350 pg/g for the fifth analyte) were lower than many of those published for the same analytes in other biomatrices, including serum and urine. These methods were tested on the skeletal remains of minipigs exposed to the chemical weapon VX in vivo. The VX metabolite was detected in multiple minipig bone samples; to the authors' knowledge, this is the first time in vivo nerve agent exposure has been detected from bone. Further, detected concentrations and diaphyseal-to-epiphyseal area count ratios reflect animal exposure history. Although the results are limited, they are promising, indicating that nerve agent metabolites may interact with bone as a pharmacokinetic compartment and can be extracted from bone postmortem. Additional studies, assessing the effects of different agents, exposure pathways and taphonomic variables, are needed; however, these results suggest the method may be used with human bone to detect use of chemical weapons from postmortem biomatrices even well after a Suspected Attack. More general implications for both nerve agent toxicology and skeletal toxicology are also discussed.
