Security assessment of audience response systems using software defined radios

Audience response systems, also known as clickers, are used at many academic institutions to offer active learning environments. Since these systems are used to administer graded assignments, and sometimes even exams, it is crucial to assess their security. Our work seeks to exploit and document potential vulnerabilities of clickers. For this purpose, we use software defined radios to perform eavesdropping attacks on an audience response system in production. The results of our study demon- strate that clickers are easily exploitable. We build a prototype and show that it is practically possible to covertly steal answers from a peer or even the entire classroom, with high levels of confidence. As a result of this study, we discourage using clickers for high-stake assessments, unless manufacturers provide proper security protection.http://people.bu.edu/staro/MIT_Conference_Khai.pdfAccepted manuscrip

Brief announcement: passive and active attacks on audience response systems using software defined radios

Audience response systems, also known as clickers, are used at many academic institutions to offer active learning environments. Since these systems are used to administer graded assignments, and sometimes even exams, it is crucial to assess their security. Our work seeks to exploit and document potential vulnerabilities of clickers. For this purpose, we use software defined radios to perform jamming, sniffing and spoofing attacks on an audience response system in production, which provide different possible methods of cheating. The results of our study demonstrate that clickers are easily exploitable. We build a prototype and show that it is practically possible to covertly steal or forge answers of a peer or even an entire classroom, with high levels of confidence. Additionally, we find that the receivers software of the system lacks protection against unexpected answers, which allows our spoofer to submit any ASCII character and opens the receiver up to possible fuzzing attacks. As a result of this study, we discourage using clickers for high-stake assessments, unless they provide proper security protection..http://people.bu.edu/staro/SSS2017_Brief_v0.pdfhttp://people.bu.edu/staro/SSS2017_Brief_v0.pdfhttp://people.bu.edu/staro/SSS2017_Brief_v0.pdfAccepted manuscrip

EFFECT OF SOME EXPERIMENTAL FACTORS ON PREPARATION OF LIQUID NATURAL RUBBER

The article presents results of effect of factors comprising the types of irradiation, the concentration of NR solution and the content of hydroperoxide in mixture on photochemical depolymerization of natural rubber. The results showed that the ultraviolet irradiation from the vapor mercury lamps (HSW-250W and HSW-125W) caused the faster rate of depolymerization than the light from  HF-500W; increasing concentration of NR in toluene leaded to decrease the rate of depolymerization; and as the content of hydroperoxide increased the rate of depolymerization was faster. Additionally, the IR spectra, 13C-NMR of products were determined and showed that the cis-1,4-isoprene structure has not been changed and there was the presence of hydroxyl-terminated groups and a few epoxy groups in chains

Destination-aware Adaptive Traffic Flow Rule Aggregation in Software-Defined Networks

In this paper, we propose a destination-aware adaptive traffic flow rule aggregation (DATA) mechanism for facilitating traffic flow monitoring in SDN-based networks. This method adapts the number of flow table entries in SDN switches according to the level of detail of traffic flow information that other mechanisms (e.g. for traffic engineering, traffic monitoring, intrusion detection) require. It also prevents performance degradation of the SDN switches by keeping the number of flow table entries well below a critical level. This level is not preset as a hard threshold but learned during operation by using a machine-learning based algorithm. The DATA method is implemented within a RESTful application (DATA App) which monitors and analyzes the ongoing network traffic and provides instructions to the SDN controller to adapt the traffic flow matching strategies accordingly. A thorough performance evaluation of DATA is conducted in an SDN emulation environment. The results show that---compared to the default behavior of common SDN controllers---the proposed DATA approach yields significant SDN switch performance improvements while still providing detailed traffic flow information on demand.Comment: This paper was presented at NetSys conference 2019. arXiv admin note: text overlap with arXiv:1909.0154

Simulation for Neutron Transport in PWR Reactor Moderator and Evaluation for Proper Thickness of Light Water Reflector

Monte Carlo calculation method can be used for resolving particle transport in matter, and particularly the transport of neutrons in environment of reactor core. The method has become more efficiently because of high accuracy of updated nuclear data and fast development of advanced super-computing system. In this work, we would like to present calculations for kinematical characteristics of neutron transport in a typical configuration of the pressurized water reactor (PWR) fuel assembly based on the Monte-Carlo simulation method. We concentrate in two main results: (1) neutron energy spectrum at fuel rod and (2) optimal thickness of light water reflector

Average molecular weight and molecular weight distribution of the Vietnamese acacia pulps.

The average molecular weight (MW) and the molecular weight distribution (MWD) of the several acacia pulps produced from wood of acacia tree in Vietnam were investigated. These chosen pulps had the various brightness were produced by Kraft method and bleaching. The MW was determined by viscosity of the pulps in copper-ammonium complex. The MWD was determined by fractional method which was carried out by dissolving pulp in the various phosphoric acids from 73.3 to 83 % in weight. The results show that these pulps have an average degree of polymerization (DP) in the range from 842 to 878. Additionally, the fraction of pulps with DP lower than 200 units is about 15 percent. The fractionations have the most percentage in the range from 600 to 1050 units. And, there are differences of MW and MWD of pulps from various brightness. Keywords. Acacia pulp, average molecular weight, molecular weight distribution

Khảo sát bệnh viêm phổi, màng phổi do vi khuẩn Actinobacillus pleuropneumoniae trên heo tại tỉnh Bến Tre

Nghiên cứu được thực hiện nhằm khảo sát sự lưu hành, xác định serotype và kiểm tra sự nhạy cảm với kháng sinh của vi khuẩn Actinobacillus pleuropneumoniae (APP) gây bệnh viêm phổi, màng phổi trên heo tại tỉnh Bến Tre. Các serotype vi khuẩn APP được xác định và định danh dựa vào gene độc tố apx từ 114 mẫu dịch xoang mũi, 15 mẫu hạch hạnh nhân và 15 mẫu phổi heo ở các lứa tuổi tại các trại, hộ chăn nuôi và lò giết mổ gia súc tại tỉnh Bến Tre bằng phương pháp PCR, kiểm tra sự nhạy cảm kháng sinh bằng phương pháp khuếch tán trên thạch. Kết quả cho thấy tỷ lệ bệnh hô hấp trên heo tại tỉnh Bến Tre là 11,52%. Tỷ lệ phân lập được vi khuẩn Actinobacillus spp. là 45,14% (65/144); APP là 24,62% (16/65). Trong 16 chủng vi khuẩn APP phân lập được có 5 chủng thuộc serotype 4; 1 chủng thuộc serotype 6 và 10 chủng thuộc serotype 9, 11. Vi khuẩn APP gây bệnh viêm phổi, màng phổi nhạy cảm với kháng sinh amoxicillin/clavulanic acid (100%), tulathromycin (81,25%), gentamicin (68,75%); và đa kháng với ít nhất 4 đến 9 loại kháng sinh gồm florfenicol, tetracycline, ampicillin, amoxicillin, bactrim, norfloxacin, neomycin, tobramycin, streptomycin

Village Baseline Study – Site Analysis Report for My Loi, Ky Anh district, Ha Tinh province – Viet Nam

Data collection for the Village Baseline Study (VBS) of My Loi village in the CCAFS benchmark site of central Viet Nam took place on 17- 19 October 2014. Focus group discussions were conducted separately for 45 men and 45 women villagers.. The VBS had three main topics: map of (1) community resources, (2) organizational landscapes, and (3) information networks. A seminar was held in December 2014 to seek participants’ feedback. My Loi village has experienced multiple extreme weather events (temperature and water stresses, storms and typhoons) throughout the years. The main constraints for agricultural development and livelihoods are limited water resources and poor conditions of irrigation systems, which are challenges to improving the agricultural production situation. Moreover, sand and rock mining have caused water pollution, erosion on riverbanks and loss of farmland area. Another constraint is marketing, as villagers are not aware of any organization involved in finding outlets for agricultural products. The potentials for developing innovative climate-smart solutions in the village are several: farmers have experiences and are interested in trying new varieties and adjusting farming calendars to improve the situation. Livestock expansion and agroforests/reforestation hold opportunities for improving household incomes. Furthermore, at least half of the organisations identified in the region are working to address food security issues

Fully Dynamic Attribute-Based Signatures for Circuits from Codes

Attribute-Based Signature (ABS), introduced by Maji et al. (CT-RSA\u2711), is an advanced privacy-preserving signature primitive that has gained a lot of attention. Research on ABS can be categorized into three main themes: expanding the expressiveness of signing policies, enabling new functionalities, and providing more diversity in terms of computational assumptions. We contribute to the development of ABS in all three dimensions, by providing a fully dynamic ABS scheme for arbitrary circuits from codes. The scheme is the first ABS from code-based assumptions and also the first ABS system offering the \texttt{full dynamicity} functionality (i.e., attributes can be enrolled and revoked simultaneously). Moreover, the scheme features much shorter signature size than a lattice-based counterpart proposed by El Kaafarani and Katsumata (PKC\u2718). In the construction process, we put forward a new theoretical abstraction of Stern-like zero-knowledge (ZK) protocols, which are the major tools for privacy-preserving cryptography from codes. Our main insight here actually lies in the questions we ask about the fundamental principles of Stern-like protocols that have remained unchallenged since their conception by Stern at CRYPTO\u2793. We demonstrate that these long-established principles are not essential, and then provide a refined framework generalizing existing Stern-like techniques and enabling enhanced constructions

Magnetic and Magnetotransport Properties of La0.7ca0.3mn1-x(zn,cu)xo3

Magnetic and magnetotransport properties of two perovskite manganite samples of La0.7Ca0.3Mn0.9Zn0.1O3 and La0.7Ca0.3Mn0.95Cu0.05O3 prepared by conventional solid-state reaction have been studied in detail. Experimental results revealed that the temperature dependences of magnetization and resistance varied strongly around the phase-transition temperature. Maximum magnetoresistance (MR) values of La0.7Ca0.3Mn0.9Zn0.1O3 and La0.7Ca0.3Mn0.95Cu0.05O3 under an applied field of 400 Oe were about 21.4 % and 11.0 %, respectively. The maximum magnetic-entropy change (ΔSM) was 2.73 J/kg.K for La0.7Ca0.3Mn0.9Zn0.1O3, and 3.34 J/kg.K for La0.7Ca0.3Mn0.95Cu0.05O3 when the applied field was 45 kOe. Both the MR and ΔSM values obtained from two samples were smaller than those of the parent compound La0.7Ca0.3MnO3. This was due to the change in the Mn3+/Mn4+ ratio caused by Zn and Cu dopants, which led to a change in the type of the ferromagneticparamagnetic phase transition