Mockingbird: Defending Against Deep-Learning-Based Website Fingerprinting Attacks with Adversarial Traces

Website Fingerprinting (WF) is a type of traffic analysis attack that enables a local passive eavesdropper to infer the victim's activity, even when the traffic is protected by a VPN or an anonymity system like Tor. Leveraging a deep-learning classifier, a WF attacker can gain over 98% accuracy on Tor traffic. In this paper, we explore a novel defense, Mockingbird, based on the idea of adversarial examples that have been shown to undermine machine-learning classifiers in other domains. Since the attacker gets to design and train his attack classifier based on the defense, we first demonstrate that at a straightforward technique for generating adversarial-example based traces fails to protect against an attacker using adversarial training for robust classification. We then propose Mockingbird, a technique for generating traces that resists adversarial training by moving randomly in the space of viable traces and not following more predictable gradients. The technique drops the accuracy of the state-of-the-art attack hardened with adversarial training from 98% to 42-58% while incurring only 58% bandwidth overhead. The attack accuracy is generally lower than state-of-the-art defenses, and much lower when considering Top-2 accuracy, while incurring lower bandwidth overheads.Comment: 18 pages, 13 figures and 8 Tables. Accepted in IEEE Transactions on Information Forensics and Security (TIFS

Effect of Increased Implant Crown Height on Fracture Strength of IPS-e.max CAD Hybrid Abutment Crown: An In-vitro Study

Introduction: The use of a secondary titanium insert has a beneficial influence on the stability of ceramic abutments and appears to be clinically useful for premolar and molar single-tooth replacements. Available titanium inserts in the market produced by Sirona, have a single height of 4.6mm with various platform diameters for different implant systems. The aim of this in-vitro study was to determine the fracture strength of IPS-e.max CAD hybrid abutment crowns with various crowns heights by simulating cyclic masticatory loads in vitro. Materials and Methods: Forty conical AstraTech EV dental implants, 4.2 mm in diameter and 9.0 mm in length were embedded 30 degree off-axis in acrylic resin blocks. Five groups (n=8/group) were designed to simulate the following treatment modalities for an implant crown #3i; Group 1 (control): Atlantis abutment and milled cemented zirconia crown with the dimensions of 11mm height, 10mm mesiodistal, 11mm buccolingual. Group 2: Atlantis CustomBase solution with milled cemented zirconia crown with the exact same dimensions as group 1. Groups 3, 4, 5: CAD/CAM hybrid abutment crown (TiBase) with the same mesiodistal and buccolingual dimensions as group 1 and different heights of the crown which were 11mm for group 3, 13mm for group 4, and 15mm for group 5. Implant position and wax-up crown were scanned with the Omnicam intraoral scanner. Lithium disilicate glass ceramic blocks (IPS e.max) were used to mill the full contour crowns in a milling machine. 100N mechanical cyclic loading at 30 degree off-axis was applied to the palatal cusps of each specimen for 250,000 cycles. Then, all survived specimens were loaded at the same angle in the universal testing machine with dislocation speed of 0.5 mm/min which increased from 0 to1000N or when fracture or deformation occurred. Removal torque value was measured after mechanical cyclic loading as well as compressive loading. A mixed-effects general linear model was employed for comparison among five groups. R-Studio and R 3.2.2 were used for all statistical analysis, and significance was accepted at p \u3c 0.05. Results: All TiBase groups did not demonstrate any significant difference in the amount of reduction in removal torque values before and after compressive loading, compared to control group (CBS). Furthermore, in the two-by-two comparison, the difference between TiBase 11mm and 15 mm was statistically significant (p value: 0.048). The fracture resistance ranged from 673.24-759.77 N for group 5, and 809.1-994.28 N for group 4. Different pattern of failure occurred for TiBase groups after compressive load test including plastic deformation of TiBase, screw bending, screw fracture, and ceramic fracture. Conclusion: Under the limitations of this study, Lithium disilicate hybrid implant supported restorations (IPS e.max CAD hybrid-abutment-crowns) with various crown heights including 11,13,15 mm did not fail during the estimate of 1-year chewing simulation. Under 1000N compressive load, all of the 15mm and most of the 13mm crowns failed, demonstrating the significant effect of the TiBase height on final fracture strength and survival of the crowns. Additional laboratory and clinical studies are needed to study the effect of the various titanium base design and abutment characteristics on the fracture strength of the complete structure

Bile bacteria of patients with cholelithiasis and theirs antibiogram

To prevent post cholecystectomy infection, the most common microorganisms causing it and their antibacterial susceptibility pattern should be determined. Therefore, the aim of the present study was to determine the exact incidence and nature of the microbial flora in the bile of the patients with cholelithiasis and chronic cholecystitis as well as their antibiotic sensitivity pattern. In this study, a total of 132 samples from the patients were tested for bacterial strains using the appropriate methods for testing them. The isolated bacteria were subsequently subjected to antibacterial susceptibility test using Kirby-Bauer method. The data were analyzed using Frequency, Chi-square and t-test. Fifty of 132 (37.87) studied patients were positive for bacteria. The most common isolated organisms were Escherichia coli (13; 26), Enterobacteriaceae (9; 18), and Salmonella typhi (7; 14). The most effective antibiotics were sequentially Amikacin, Ceftriaxone, and Clindamycin. Isolating bacteria and determining their sensitivity to different antibiotics may be help physicians take prophylactic measures against postoperative infection of cholelithiasis and chronic cholecystitis. © 2013 Tehran University of Medical Sciences. All rights reserved

The Influence of Incorrect Customs of Lifestyle in Hepatitis B Infection Transmission.

Hepatitis B (HB) disease occurs with high risk behaviors in the different communities. Aim of this study was to find out some of local customs in lifestyle that might be risk factors for transmitting this disease in order to design the educational programs and control it periodically in Chaharmahal VA Bakhtiari, Iran. This was a case-control study, carried out on patients with HB and the control group in Buldaji's district since October 2008 to March 2011. An expert person interviewed both these groups with a valid and reliable questionnaire. The data were gathered and analyzed by descriptive statistics; Chi-square and logistic regression.A total of 85 patients with HB were enrolled in the study. Four of wrong customs were considered as predicting risk factors for transmission of hepatitis B infection in two groups; history of making shallow incisions on the auricle or leg for healing a disease or exchanging their blood in childhood [P=0.000, OR=6.130, 95%CL: 2.648-14.192], tattooing [P=0.033, OR=1.391, 95%CL: 1.028-1.882], be born at home by an untrained midwife [P=0.005, OR=3.217, 95%CL: 1.425-7.263], receiving dental services by experimental dentists [P=0.034,OR=0.218, 95%CL: 0.053-0.893]. For development of health education materials' in our region, we focus not only on proper prevention of general risk factors of HBV transmission but also necessarily draw upon local social and cultural contexts which may spread this disease .We encourage the people to improve these customs or don't do it to control transmission of HB

The Survey Effectiveness of Active Method in Communicable Disease Surveillance

Background and purpose: Surveillance is a system of continuing health checks, is considered as a critical part of public health practice for planning and implantation of effective prevention and control interventions for communicable diseases in the region. The aim of this study was to determine the effects of an active method of data collection on the improvement of these diseases surveillance. Materials and Methods: This research was an interventional study that carried out from January 2011 to January 2013. We surveyed the number of reporting communicable diseases before and after this modification on collecting data in our region and compared them. We changed the method of data collection from passive to active by experts. The collected data analysis was performed by SPSS software using descriptive statistics and independent samples t-test. Results: A total of 763 physicians enrolled, of whom 327 were employed in the health centers non-affiliated to the university. In the centers non-affiliated to the university, the mean reporting from these centers were 12.0 ± 8.7 [95% confidence interval (CI): 11.1-13.0] after the intervention, compared with 2.8 ± 3.7 (95% CI: 2.4-3.2) before the intervention. The mean reporting from affiliated centers did not change considerably after the intervention (11.7 ± 16.1 vs. 12.1 ± 16.3). The mean reporting of both groups in 2012 was significantly different from that in 2011 (P < 0.001). But no difference was observed between mean reporting of two groups throughout 2012 (P = 0.998). Conclusion: We recommend the active method for collecting data of communicable disease, especially from the physicians in centers non-affiliated to the universit

Hysteresis Motor Driven One Axis Magnetically Suspended Reaction Sphere

The Attitude and Orbit Control System (AOCS) plays an essential role in the flight control of a spacecraft. This system usually contains a minimum of three reaction wheels (often 4-5 wheels are used for optimization and redundancy). By accelerating the appropriate wheels, the system can produce a zero-mean reaction torque about any axis to the spacecraft, which enables the spacecraft to maneuver on orbit. Meanwhile, the momentum generated by acceleration can be stored in the wheels.Lincoln Laboratory. Advanced Concepts Committe

Improving the polishing process for Rockwell hardness test block

Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2009.Cataloged from PDF version of thesis.Includes bibliographical references (p. 49).Inefficiencies in a Rockwell hardness test block manufacturing process were analyzed. The polishing stage was identified to be the bottleneck with a high reworking rate. An understanding based on the physics of polishing was the first step. Then a DOE analysis was implemented to find the optimum parameters of polishing process. A range of solutions were implemented and improvements were observed. Adding compliance, introducing two stages of polishing and using a different pad and slurry were key elements in improving the polishing process. Various quality control factors were assessed. Early analysis of those optimized parameters appeared promising; where the average polishing cycle times for brass and steel were reduced from 20 minutes to less than 2 minutes and 4 minutes, respectively. Meanwhile the quality of surface finish was improved significantly.by Mohammad Imani Nejad.M.Eng

A Bibliometric Analysis of International Journal of Nursing Studies (1963 – 2018)

Purpose- This study set to present a general overview of the International Journal of Nursing Studies (IJNS) from 1963 to 2018 using bibliometric indicators to assess its performance. Design/methodology/approach- This study is a bibliometric analysis. The articles of the IJNS were analyzed. Scopus database was used for collecting articles. Excel software was used to analyze the process of publishing journal articles, identify top countries, institutes, and authors and extract highly cited articles in the journal. The visualization of the keywords in the articles published in the journal was done using the VOSviewer software. Findings- The results of the bibliometric analysis showed that the United Kingdom with 966 papers, King\u27s College London with 130 papers and Bergman R with 25 papers were the most productive and influential countries, universities, and authors contributing to the IJNS. The paper of Keeney S. (2001), entitled A critical review of the Delphi technique as a research methodology for nursing , was the most highly cited article in the IJNS from the beginning of 1963 to the end of 2018. The clustering of published keywords suggests that psychometric and nursing care issues are emerging journal clusters added to the journal in the last two decades. Conclusion- The evolution process of the IJNS is positive and growing. This Journal has attracted much attention from researchers and authors around the world as a pioneer and leading journalist in the field of nursing. Originality/value- This is the first comprehensive study offering a bibliometric overview of the leading trends of the IJNS over its history