99 research outputs found
Reverse Engineering for Fun and BoF It! [video]
No full textReverse engineering (RE) skills are handy in a number of situations. Determining the behavior of malware, discovery of software vulnerabilities and showing off to your friends are just a few of the benefits that immediately come to mind. Unfortunately reverse engineers are mostly self trained, work in solitude and do not openly work together when developing tools and techniques. This goal of this session is to present some of our ideas and tools (past, present and future) to foster an open discussion on RE tools as well as field suggesstions for the continued development of these tools.
Pedram Amini currently leads the Product Security Assessment team at TippingPoint, a division of 3Com. Previous to TippingPoint, he was the assistant director of iDEFENSE Labs and remains the reigning foosball champion after an intense final battle with understudy Adam Greene. Despite the fancy titles he spends much of his time developing automation tools, plug-ins and scripts for software like IDA Pro and OllyDbg. In conjunction with his passion for the field, Pedram launched OpenRCE.org, a community website dedicated to the art of reverse engineering. Chris Eagle is the Associate Chairman of the Computer Science Department at the Naval Postgraduate School (NPS) in Monterey, CA. A computer engineer/scientist for 19 years, his research interests include computer network operations, computer forensics and reverse/anti-reverse engineering
Analysis of Network Traffic Flows for Centralized Botnet Detection
No full textAt present, the Internet users are facing the most serious threats considering the malwares have become a powerful tool for attackers. Botnets are one of the most significant malwares. A Bot is an intelligent program run by worms, Trojans or other malicious codes that could perform a group of cyber-attacks on the Internet. Botnets are used for attacks such as stealing data, spam, denial-of-service, phishing etc. A variety of methods and algorithms have been proposed to detect botnets, in which each of them has an emphasis on specific data or methods. Using Netflow data is an effective and agile method compared to other methods in detecting botnets. This research focuses on centralized and HTTP botnets. In the proposed method, we used the hierarchical clustering, XMeans clustering, and rule-based classification. The methods helped to achieve fast and accurate recognition. Hierarchical clustering improved the speed and accuracy rate in the process of separating the flows. The X-Means algorithm led to the highest cohesion inside the clusters and the maximum distance between clusters by choosing optimal K. Using rule-based classification, each cluster with the similar flow is placed in a bot cluster, a semi-bot cluster or a normal cluster. By performing network traffic flow analysis for the proposed method, sets of botnets have been evaluated and the results indicated that more than 95% accuracy in detection. By a minimum overhead, this approach can provide botnet detection with high accuracy and speed
An evaluation of the Massachusetts Department of Housing and Community Development's Moving to Work voucher program
Get PDFThesis (M.C.P.)--Massachusetts Institute of Technology, Dept. of Urban Studies and Planning, 2009.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Includes bibliographical references (p. 85-87).Since implementation nearly 10 years ago there has been limited research into the outcomes of the Massachusetts Department of Housing and Community Development's Moving to Work rental subsidy program. The Congressionally authorized Moving to Work Demonstration program (MtW) deregulated housing agencies in order to provide flexibility to design and test innovative approaches to administering housing assistance programs. In 1999, DHCD began planning and implementation for two MtW pilots, one in Boston, targeting the shelter population, and another in Southern Worcester County, targeting working or "work-ready" households. The current program design provides 183 clients with fixed shallow rental subsidy amounts, support budgets, time limits, and case management to encourage and facilitate self-sufficiency. Preparing to transition its full HCVP portfolio to MtW status, DHCD initiated a process of evaluation and learning focused on the pilots. These lessons, which involve data collection processes and program implementation as well as outcomes, will inform the future of the statewide MtW program. This research is a qualitative and quantitative assessment of both pilot programs. The research used available baseline and current client employment, income and locational data to determine how effective DHCD's MtW model was at facilitating self-sufficiency. Additionally, focus groups with MtW clients and interviews with administrators were conducted to understand the impact and effectiveness of the program from multiple perspectives.(cont.) Using various poverty and self-sufficiency, measures, the research finds that, in general, the program has successfully kept clients out of "deep poverty" but has not moved them out of poverty. Hence, the program has fallen short on facilitating economic self-sufficiency. The paper concludes with a set of recommendations for DHCD's future implementation and expansion efforts.by Pedram Mahdavi.M.C.P
Integrated effects of inherent and induced anisotropy on reliquefaction resistance of Toyoura sand with different strain histories
No full textRecent earthquakes in New Zealand and Japan showed that pre-shaking histories significantly affected the reliquefaction resistance of soils. In this study, a series of experimental tests was conducted to elucidate the coupled effects of inherent and induced anisotropy on reliquefaction resistance of Toyoura sand, which have not been studied before. Accordingly, loose and dense Toyoura sands were prepared with two different methods: dry deposition and moist tamping. The specimens were sheared cyclically using a hollow cylinder torsional shear apparatus under various cyclic stress ratios up to different residual shear strains (3res) and reconsolidated at different states. The experimental results were assessed from various perspectives, including stress-strain relationships, failure mechanisms, liquefaction/reliquefaction resistance, excess pore water pressure (EPWP) generation and compressibility in conjunction with micromechanical interpretations. It was shown that fabric evolution affects the reliquefaction characteristics of Toyoura sand substantially. Interestingly, a unique correlation exists between EPWP and shear strain accumulation for all tests. An energy-based model was developed to uniquely correlate the dissipated energy with the cyclic resistance based only on residual shear strains; this model shows great promise to develop a unified, energy-based criterion for quantifying the liquefaction/reliquefaction resistance of soils with different fabrics.</p
Adaptive block backstepping control for civil structures with unknown parameters subjected to seismic excitation
No full textEffect of fabric anisotropy on reliquefaction resistance of toyoura sand based on torsional shear experiments
No full textMultiple occurrences of liquefaction, termed as “reliquefaction,” have been observed during the recent earthquakes in Japan (2011) and New Zealand (2010-2011). These field observations indicated that once the soil liquefies, the reliquefaction resistance may become weaker despite an increased density due to the postliquefaction reconsolidation. This reduction in reliquefaction resistance is linked to the fabric anisotropy developed during liquefaction or large preshearing, but quantifying its effect still remains a challenge and is not yet fully understood. In this thesis, a comprehensive and fundamental experimental program was designed to investigate the role of fabric anisotropy on the reliquefaction resistance of Toyoura sand using a hollow cylinder torsional shear apparatus. The results were analyzed from various standpoints, and the major findings are summarized as follows: In order to explore the role of induced fabric anisotropy, reliquefaction tests were conducted on Toyoura sand of different densities (i.e., Dr=45% and 70%), which experienced different residual shear strains (γres= 0.4%-5.0%)and reconsolidated at different states of A (i.e., zero shear stress state, after stress reversal) and B (i.e., zero shear strain state). The results showed that a medium preshearing (i.e., γres= 0.4%) increases reliquefaction resistance significantly, while the reliquefaction resistance decreases when the Toyoura sand experiences a large preshearing (i.e., γres ≥ 2.0%). For all tests conducted in this study, γres of 1.0%~2.0% can be considered as a threshold above which the reliquefaction resistance of sand tends to decrease. It is also worth noting that specimens reconsolidated at state A have less reliquefaction resistance at the same residual strain levels compared to the specimens reconsolidated at B, which can be explained by a higher degree of induced anisotropy in samples reconsolidated at A. However, in loose Toyoura sands, there was no significant difference between specimens reconsolidated at A and B once they were largely presheared. All in all, the effect of reconsolidation state in loose sands is not as significant as that in dense ones. Moreover, to highlight the role of inherent anisotropy, reliquefaction tests were conducted on loose Toyoura sand prepared with different methods of dry deposition (DD) and moist tamping (MT). Medium preshaken MT Toyoura sands showed much higher reliquefaction resistance than those of DD ones. Regardless of the reconstitution method, medium preshaken sands reconsolidated at state A showed a lower reliquefaction resistance than those reconsolidated at state B. However, the effects of the initial fabric and reconsolidation state are lost once the loose Toyoura sand is largely persheared. Therefore, reliquefaction resistance is almost similar for loose Toyoura sands, which presheared largely irrespective of reconstitution method and reconsolidation state. Based on experimental data, an energy-based method was developed to quantify the liquefaction and reliquefaction resistance of Toyoura sand. It was found that the dissipated energy (i.e., capacity energy) to reliquefaction was mostly greater than those of liquefaction tests regardless of relative density, inherent/induced anisotropies, and cyclic stress ratio (CSR). It was also found that most of the sands reconsolidated at point B showed consistently higher capacity energy than those reconsolidated at point A. This indicates a systematic difference in the soil fabric developed at points A and B from an energy-based standpoint. Furthermore, capacity energy to liquefaction or reliquefaction can be uniquely determined irrespective of cycle number, N, and CSR, except for a few cases of loose virgin and medium preshaken MT Toyoura sand. Furthermore, a new energy-based model with one calibration parameter was developed for predicting excess pore water pressure (EPWP) buildup during liquefaction and reliquefaction for the first time. Finally, correlations between the dissipated energy and cyclic resistance ratio (CRR20) were established based on different preshearing histories. The results provided a linkage between the energy-based method and the conventional stress-based method for evaluating the liquefaction and reliquefaction resistance of sands.</p
PCB-Vision: A Multiscene RGB-Hyperspectral Benchmark Dataset of Printed Circuit Boards
No full textPCB-Vision Dataset
Description:
The PCB-Vision dataset is a multiscene RGB-Hyperspectral benchmark dataset comprising 53 Printed Circuit Boards (PCBs). The RGB images are collected using a Teledyne Dalsa C4020 camera on a conveyor belt, while hyperspectral images (HSI) are acquired with a Specim FX10 spectrometer. The HSI data contains 224 bands in the VNIR range [400 - 1000]nm.
Data Format
RGB Images: .png files
PCB Masks: .jpg files
HSI Data: Each hyperspectral data cube is accompanied by a data file and a .hdr file.
Folder Organization
PCBVision
HSI/
53 subfolders (one for each PCB)
'General_masks' folder for 'General' segmentation ground truth
'Monoseg_masks' folder for 'Monoseg' segmentation ground truth
'PCB_Masks' folder for masks of the 53 PCBs in the hyperspectral cube
RGB/
53 .jpg images
'General' folder for RGB images 'General' segmentation ground truth
'Monoseg_masks' folder for RGB images 'Monoseg' segmentation ground truth
Data Classes in Masks
Masks (both 'General' and 'Monoseg') contain 1 to 4 segmentation classes:
0: "Others"
1: "IC"
2: "Capacitors"
3: "Connectors"
Code Repository
To facilitate reading and working with the data, Python codes are available on the GitHub repository:
https://github.com/hifexplo/PCBVision
Citation
If you use this dataset, please cite the following article:
Word:
Arbash, Elias, Fuchs, Margret, Rasti, Behnood, Lorenz, Sandra, Ghamisi, Pedram, & Gloaguen, Richard. (2024). PCB-Vision: A Multiscene RGB-Hyperspectral Benchmark Dataset of Printed Circuit Boards (Version 1) [Data set]. Rodare. http://doi.org/10.14278/rodare.2704
Latex:
@article{arbash2024pcb, title={PCB-Vision: A Multiscene RGB-Hyperspectral Benchmark Dataset of Printed Circuit Boards}, author={Arbash, Elias and Fuchs, Margret and Rasti, Behnood and Lorenz, Sandra and Ghamisi, Pedram and Gloaguen, Richard}, journal={arXiv preprint arXiv:2401.06528}, year={2024} }
Contact
For further information or inquiries, please visit our website:
https://www.iexplo.space/
Contact Email: [email protected]
Effect of Fabric Anisotropy on Reliquefaction Resistance of Toyoura Sand: An Experimental Study
No full textRecent earthquakes in New Zealand and Japan demonstrated that pre-shaking histories can significantly influence the liquefaction resistance of sandy soils, which has not been fully understood yet. It has also been reported that soils prepared with different depositional methods referred to as initial or inherent anisotropy show different liquefaction behavior. Therefore, a comprehensive experimental study was carried out for the first time to explore the combined effects of inherent anisotropy and induced anisotropy due to cyclic shearing on the reliquefaction resistance of loose (Dr = 45%) and dense (Dr = 70%) Toyoura sands subjected to various cyclic stress ratios (CSR). A hollow cylinder torsional shear apparatus (HCTSA) was used in this study since it can mimic the field stress conditions more realistically during earthquake events. In order to investigate the influence of inherent anisotropy on liquefaction and reliquefaction resistance of Toyoura sand, the hollow cylindrical specimens were reconstituted with different methods of dry deposition (DD) and moist tamping (MT), representing naturally and artificially deposited soils, respectively. Furthermore, sand specimens were cyclicly sheared up to medium and large shear strain levels, then reconsolidated at different states to evaluate the effect of induced anisotropy with different shear histories on reliquefaction resistance in the sand. A large preshearing reduces the reliquefaction resistance, while the reliquefaction resistance increases when the sandy soil is moderately presheared, irrespective of relative density and reconsolidation state. It was also found that the effect of reconsolidation state is more significant in the dense sand than the loose sand. Another key finding of this study is that the effects of initial fabric acquired by different reconstitution methods and reconsolidation states are lost in the reliquefaction tests once the loose Toyoura sands experienced large preshaking.</p
Effect of induced anisotropy on postliquefaction and reliquefaction resistance of sand: experimental study
No full textRecent advances in the synthesis and application of magnetic biochar for wastewater treatment
No full textMagnetic biochar (MBC) is a novel bio-carbon material with both desired properties as adsorbent and magnetic characteristics. This review provides an up-to-date summary and discussion on the latest development of MBC, which covers the progress on its synthesis, application, and techno-economic analysis. The review indicates that the direct hydrothermal synthesis has been catching more research attention to produce MBC due to its mild reaction conditions. Instead of the Fe-loaded MBC, there is a trend of using Mn for the magnetization. For the MBC application, how to improve its adsorption performance for water decontamination, ideally to match that of the biochar (BC) or activated carbon, is important. In addition, more studies on the environmental impacts of MBC and life-cycle assessment decoding the process optimization options are necessary. This review will provide valuable references for the development of MBC and MBC-based materials for wastewater treatment
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