Device Fingerprinting with Magnetic Induction Signals Radiated by CPU Modules

With the widespread use of smart devices, device authentication has received much attention. One popular method for device authentication is to utilize internally measured device fingerprints, such as device ID, software or hardware-based characteristics. In this article, we propose DeMiCPU , a stimulation-response-based device fingerprinting technique that relies on externally measured information, i.e., magnetic induction (MI) signals emitted from the CPU module that consists of the CPU chip and its affiliated power-supply circuits. The key insight of DeMiCPU is that hardware discrepancies essentially exist among CPU modules and thus the corresponding MI signals make promising device fingerprints, which are difficult to be modified or mimicked. We design a stimulation and a discrepancy extraction scheme and evaluate them with 90 mobile devices, including 70 laptops (among which 30 are of totally identical CPU and operating system) and 20 smartphones. The results show that DeMiCPU can achieve 99.7% precision and recall on average, and 99.8% precision and recall for the 30 identical devices, with a fingerprinting time of 0.6~s. The performance can be further improved to 99.9% with multi-round fingerprinting. In addition, we implement a prototype of DeMiCPU docker, which can effectively reduce the requirement of test points and enlarge the fingerprinting area.

OPTIMAL DESIGN OF CYLINDRICAL GEARS WITH CONVEX-CONCAVE CONTACT: OBJECTIVE FUNCTION AND VARIABLES PLANNING

Reducing the mass and dimensions of gears is an actual task of modern mechanical engineering. One of the perspective ways to solve it is the use of gearing with a convex-concave contact of the teeth. Therefore, the study is devoted to the development of methods for the optimal design of cylindrical gears with convex-concave contact of the working surfaces. Optimality criteria: minimum contact stresses and (or) minimum relative sliding velocities, taking into account design, geometrical and technological constraints. C-C gearing was chosen as the object of research. It was proposed by the Slovak scientists M. Boshanski and M. Veresh. An objective function is constructed for the case of minimizing contact stresses. The optimality criterion is formulated as follows: contact stresses σH in the mesh must take the minimum possible value when all constraints are met. An objective function is also constructed for the case of minimizing the relative sliding velocities of profiles. The optimality criterion is formulated as follows: the relative sliding s velocities of profiles λ at the extreme points of mesh must take the minimum possible value when all the constraints are met. Variables planning are defined. These are pressure angle at the pole αС, the curvature radius at the upper part of contact path rkh, and the curvature radius at the lower part of contact path rkd. A method for solving the problem of optimal design is chosen. The method of probing the space of design parameters was chosen from all the variety. The points of the LPτ-sequence are used as test points. The method allows you to operate with a significant number of parameters – up to 51, provides a sufficiently large number of evenly distributed test points – up to 220. In further studies, it is planned to form a system of constraints on variables planning, to develop methods and algorithms for solving the problem. Also carry out test and verification calculations to confirm and evaluate the theoretical results. Keywords: gear, convex-concave contact, optimal design, objective function, variables planning

GIS Mapping of Short-Term Noisy Event of Diwali Night in Lucknow City

Noise is a universal problem that is particularly prominent in developing nations like India. Short-term noise-sensitive events like New Year’s Eve, derby matches, DJ night, Diwali night (celebration with firecracker) in India, etc. create lots of noise in a short period. There is a need to come up with a system that can predict the noise level for an area for a short period indicating its detailed variations. GIS (Geographic Information System)-based google maps for terrain data and crowd-sourced or indirect collection of noise data can overcome this challenge to a great extent. Authors have tried to map the highly noisy Diwali night for Lucknow, a northern city of India. The mapping was done by collecting the data from 100 points using the noise capture app (30% were close to the source and 70% were away from the source (receiver). Noise data were predicted for 750 data points using the modeling interpolation technique. A noise map is generated for this Diwali night using the crowd-sourcing technique for Diwali night. The results were also varied with 50 test points and are found to be within ±4.4 dB. Further, a noise map is also developed for the same site using indirect data of noise produced from the air pollution open-sourced data. The produced noise map is also verified with 50 test points and found to be ±6.2 dB. The results are also corroborated with the health assessment survey report of the residents of nearby areas.

NATIONAL SCALE REAL-TIME SURVEILLANCE OF SARS-COV-2 VARIANTS DYNAMICS BY WASTEWATER MONITORING IN ISRAEL

In this report, we describe a national-scale monitoring of the SARS-COV-2 (SC-2) variant dynamics in Israel, using multiple-time sampling of twelve wastewater treatment plants. We used a combination of inclusive and selective quantitative PCR assays that specifically identify variants A19 or B.1.1.7 and tested each sample for the presence and relative viral RNA load of each variant. We show that between December-2020 and March-2021, a complete shift in the SC-2 variant circulation was observed, where the B.1.1.7 replaced the A19 in all examined test points. We further show that the normalized viral load (NVL) values and the average new cases per week reached a peak in January 2021, and then decreased gradually in almost all test points, in parallel with the progression of the national vaccination campaign, during February-March 2021. This study demonstrates the importance of monitoring SC-2 variant dynamics on a national scale through wastewater sampling. It also provides a proof-of-concept methodology for continuous surveillance by using a combination of inclusive and selective PCR tests, which is far more amendable for high throughput monitoring compared with sequencing. This approach may be useful for real-time dynamics surveillance of current and future variants, such as the Omicron (BA.1) variant.

Application of a Pattern-Recognition Neural Network for Detecting Analog Electronic Circuit Faults

In this study, machine learning techniques based on the development of a pattern–recognition neural network were used for fault diagnosis in an analog electronic circuit to detect the individual hard faults (open circuits and short circuits) that may arise in a circuit. The ability to determine faults in the circuit was analyzed through the availability of a small number of measurements in the circuit, as test points are generally not accessible for verifying the behavior of all the components of an electronic circuit. It was shown that, despite the existence of a small number of measurements in the circuit that characterize the existing faults, the network based on pattern-recognition functioned adequately for the detection and classification of the hard faults. In addition, once the neural network has been trained, it can be used to analyze the behavior of the circuit versus variations in its components, with a wider range than that used to develop the neural network, in order to analyze the ability of the ANN to predict situations different from those used to train the ANN and to extract valuable information that may explain the behavior of the circuit.

Testability Analysis Method of Radar Equipment Based on Dependency Model

In order to improve the testability design level of radar equipment, achieve rapid detection and isolation of faults, and reduce the life cycle cost of the system, a testability analysis method of radar equipment based on correlation model is proposed. The basic process of correlation model modeling is introduced. On this basis, the optimization method of test points for fault detection and isolation and the generation method of fault diagnosis strategy are analyzed. The effectiveness of the proposed method is verified by applying it to radar transmitting subsystem.

Using Perspective-n-Point Algorithms for a Local Positioning System Based on LEDs and a QADA Receiver

The research interest on location-based services has increased during the last years ever since 3D centimetre accuracy inside intelligent environments could be confronted with. This work proposes an indoor local positioning system based on LED lighting, transmitted from a set of beacons to a receiver. The receiver is based on a quadrant photodiode angular diversity aperture (QADA) plus an aperture placed over it. This configuration can be modelled as a perspective camera, where the image position of the transmitters can be used to recover the receiver’s 3D pose. This process is known as the perspective-n-point (PnP) problem, which is well known in computer vision and photogrammetry. This work investigates the use of different state-of-the-art PnP algorithms to localize the receiver in a large space of 2 × 2 m2 based on four co-planar transmitters and with a distance from transmitters to receiver up to 3.4 m. Encoding techniques are used to permit the simultaneous emission of all the transmitted signals and their processing in the receiver. In addition, correlation techniques (match filtering) are used to determine the image points projected from each emitter on the QADA. This work uses Monte Carlo simulations to characterize the absolute errors for a grid of test points under noisy measurements, as well as the robustness of the system when varying the 3D location of one transmitter. The IPPE algorithm obtained the best performance in this configuration. The proposal has also been experimentally evaluated in a real setup. The estimation of the receiver’s position at three particular points for roll angles of the receiver of γ={0°, 120°, 210° and 300°} using the IPPE algorithm achieves average absolute errors and standard deviations of 4.33 cm, 3.51 cm and 28.90 cm; and 1.84 cm, 1.17 cm and 19.80 cm in the coordinates x, y and z, respectively. These positioning results are in line with those obtained in previous work using triangulation techniques but with the addition that the complete pose of the receiver (x, y, z, α, β, γ) is obtained in this proposal.

Transitioning from Time Based to Risk Based Inspection (RBI) for Static Equipment at Banyu Urip Facility

This paper discusses the strategies, implementation, and benefits of the transition from time-based to risked-based inspections (RBI) for static equipment in Banyu Urip Facility. A review of facility integrity programs was conducted to pressure vessel (PV) and tank inspection results to assess the effectiveness of associated integrity programs. This data was utilized as a basis for risk assessment to determine if an RBI program was fit for the purpose to extend inspection intervals for static equipment. The implementation of RBI in Banyu Urip Facility began with carbon steel pressure vessels and tanks. These static equipment were jointly evaluated by multiple functions to ensure seamless execution and timely analysis of data. Inspection packages were developed, which considered applicable degradation mechanisms to select representative test points and ensure consistency for future inspection. All inspection packages consisted of general arrangement drawings depicting vessels and associated test points. Once reviewed and approved, this information was documented in Asset Integrity Management Software to streamline future campaigns. Each vessel was independently evaluated for RBI suitability including the identification of credible failure mode and details of potential future inspection requirements. Outcomes of this evaluation were transmitted into fit for risk inspection interval that provides cost reduction opportunity while maintaining equipment integrity. Furthermore, it also help to drive focus toward higher criticality equipment. This approach is also being considered for other types of static equipment, including piping and PSV.

The influence of distance learning on the level of preparation of participants of the profile-level Mathematics unified exam of the Russian state

In connection with the harsh situation in the world in the spring of 2020, there was a problem with the organisation of school education throughout Russia. This article is devoted to the influence of distance learning on the results of the unified state exam in Mathematics (profile level). First of all, the dynamics of the total number of participants in the Maths exam over the past three years was considered. The article goes on to analyse the changes that occurred in 2020 in the content of control and measurement materials for Kostroma Region. The results of the exam participants were analysed in several groups – those who had not reach the minimum score, those who had scored 40 points or less, from 41 to 60 points, from 61 to 80 points and from 81 to 100 test points. Methods of qualitative and quantitative assessment (Pearson's criterion is applied) of percentage distributions of results of exam participants in various groups for 2019-20 years are described. Conclusions are drawn about the impact of the distance learning period on the results of the Maths exam.

ON THE EFFECT OF THE SIDE FLOW OF 316L STAINLESS STEEL IN THE FINISH TURNING PROCESS UNDER DRY CONDITIONS

The article presents the results of the research on the plastic flow in the finish turning of 316L (X2CrNiMo17-12-2) stainless steel under dry cutting conditions. The steel was turned at variable cutting speeds and a constant depth of cut. The investigations were based on the Parameter Space Investigation method (PSI) which allowed minimizing the number of test points. It was observed that the phenomenon of slide flow occurred in the range of cutting speeds and feed rates under examination and its intensity depended on the values of these parameters. The phenomenon was more intense in the range of medium and higher cutting speeds and lower feed rates. The side flow results in significant changes between the real and theoretical values of roughness parameter Rz, which range from 40% up to even 330%.