Investigating SRAM PUFs in large CPUs and GPUs

Physically unclonable functions (PUFs) provide data that can be used for cryptographic purposes: on the one hand randomness for the initialization of random-number generators; on the other hand individual fingerprints for unique identification of specific hardware components. However, today's off-the-shelf personal computers advertise randomness and individual fingerprints only in the form of additional or dedicated hardware. This paper introduces a new set of tools to investigate whether intrinsic PUFs can be found in PC components that are not advertised as containing PUFs. In particular, this paper investigates AMD64 CPU registers as potential PUF sources in the operating-system kernel, the bootloader, and the system BIOS; investigates the CPU cache in the early boot stages; and investigates shared memory on Nvidia GPUs. This investigation found non-random non-fingerprinting behavior in several components but revealed usable PUFs in Nvidia GPUs.Comment: 25 pages, 6 figures. Code in appendi

Procedures and Techniques for Conducting a Fort Hays Kansas State College Curriculum Evaluation in the Public Schools

The Educational Field Service at Fort Hays Kansas State College was organized to provide service to schools in western Kansas. Much of the research, calculation, and evaluation is done by graduate students under the guidance of college consultants and this paper is designed to show a step by step procedure of the processes involved in carrying out an Educational Field Service Survey. It is hoped that this report will be of particular value to those students working with the Fort Hays Kansas State College Educational Field Service but it may also offer suggestions for any studies requiring the conducting of curriculum evaluations in the public schools. Studies by the Educational Field Service are done at the request of school boards who wish to have the building facilities and curriculum of their local schools evaluated any recommendations for improvement then made. This report will not cover the techniques and procedures used in evaluating building facilities. It will be limited to the procedures and techniques employed in conducting a Fort Hays Kansas State College curriculum evaluation in public schools and will include some criteria for checking drafts of final curriculum reports. Graduate students from the Department of Education at Fort Hays Kansas State College assist the directors of the Educational Field Service in administering and evaluating a statement of objectives known as the Behavioral Outcomes Q-Sort, which will be explained later in this report. They also help present materials an outlines to the teachers of the school being evaluated, and offer methods and suggestions on completing them. After the teachers have completed these outlines, showing what is being taught on various grade levels, the graduate students place this information on a flow chart which will show what is being taught in a given subject or area from the first grade through the twelfth. The information obtained in this manner is sent to subject matter specialists from Fort Hays Kansas State College who analyze the program in terms of content, time allotment, and method of teaching and make recommendations for curricular improvement. The graduate students then condense and organize this material into the final report. In this manner a close-working relationship can be developed between the college and local operating school systems in western Kansas. Also, by having subject matter specialists at Fort Hays State College assist in various areas, these school systems can enjoy the benefits of individual help with their own particular problems. The development of a curriculum evaluative report consists of the following step by step procedure. 1. Administering the Behavioral Outcomes Q- Sort and Relative Responsibility Questionnaire. 2. Determining the results of the questionnaire. 3. Explanation of the results of the questionnaire. 4. Presentation of curriculum information gathering devices. 5. Evaluating the curriculum data. 6. Presenting curriculum evaluative data to college consultants. 7. Writing the final curriculum report. 8. Checking the drafts of final curriculum report

Symmetry of standing waves generated by a point defect in epitaxial graphene

Using scanning tunneling microscopy (STM) and Fourier Transform STM (FT-STM), we have studied a point defect in an epitaxial graphene sample grown on silicon carbide substrate. This analysis allows us to extract the quasiparticle energy dispersion, and to give a first experimental proof of the validity of Fermi liquid theory in graphene for a wide range of energies from -800 meV to +800 meV. We also find evidence of a strong threefold anisotropy in the standing waves generated by the defect. We discuss possible relations between this anisotropy, the chirality of the electrons, and the asymmetry between graphene's two sublattices. All experimental measurements are compared and related to theoretical T-matrix calculations.Comment: 4 pages, 4 figure

In-situ surface technique analyses and ex-situ characterization of Si1-xGex epilayers grown on Si(001)-2 ×1 by molecular beam epitaxy

Si1-xGex epilayers grown by Molecular Beam Epitaxy on Si(001) at 400 ○C have been analyzed in-situ by surface techniques such as X-ray and Ultraviolet Photoelectron Spectroscopies (XPS and UPS), Low Energy Electron Diffraction (LEED) and photoelectron diffraction (XPD). The Ge surface concentrations (x) obtained from the ratios of Ge and Si core level intensities are systematically higher than those obtained by the respective evaporation fluxes. This indicates a Ge enrichment in the first overlayers confirmed by Ge-like UPS valence band spectra. The structured crystallographic character of the epilayers is ascertained by LEED and XPD polar scans in the (100) plane since the Ge Auger LMM and the Si 2p XPD intensity patterns from the Si1-xGex epilayers are identical to those of the Si substrate. The residual stress in the epilayer is determined by ex-situ X-ray diffraction (XRD) which also allows, as Rutherford Back Scattering (RBS), Ge concentration determinations

Fourier Transform Scanning Tunneling Spectroscopy: the possibility to obtain constant energy maps and the band dispersion using a local measurement

We present here an overview of the Fourier Transform Scanning Tunneling spectroscopy technique (FT-STS). This technique allows one to probe the electronic properties of a two-dimensional system by analyzing the standing waves formed in the vicinity of defects. We review both the experimental and theoretical aspects of this approach, basing our analysis on some of our previous results, as well as on other results described in the literature. We explain how the topology of the constant energy maps can be deduced from the FT of dI/dV map images which exhibit standing waves patterns. We show that not only the position of the features observed in the FT maps, but also their shape can be explained using different theoretical models of different levels of approximation. Thus, starting with the classical and well known expression of the Lindhard susceptibility which describes the screening of electron in a free electron gas, we show that from the momentum dependence of the susceptibility we can deduce the topology of the constant energy maps in a joint density of states approximation (JDOS). We describe how some of the specific features predicted by the JDOS are (or are not) observed experimentally in the FT maps. The role of the phase factors which are neglected in the rough JDOS approximation is described using the stationary phase conditions. We present also the technique of the T-matrix approximation, which takes into account accurately these phase factors. This technique has been successfully applied to normal metals, as well as to systems with more complicated constant energy contours. We present results recently obtained on graphene systems which demonstrate the power of this technique, and the usefulness of local measurements for determining the band structure, the map of the Fermi energy and the constant-energy maps.Comment: 33 pages, 15 figures; invited review article, to appear in Journal of Physics D: Applied Physic

Group suckling in organic sow units

Group suckling - a combined system of single and group housing of lactating sows - appears a suitable system for organic pig production. The aim of the study was to describe the status quo of group suckling in organic farms. 31 organic sow units in Germany, Austria and Switzerland were investigated. Stockmen were interviewed, stables were inspected and animals were examined during three visits on each farm enterprise, respectively. The majority of farms kept three sows with piglets in one group suckling unit. 76 % of the group suckling sows (n=192) were in a good nutritional condition, 18 % were considered thin and 8 % of sows were too fat. Relatively few sows showed skin lesions caused by poor housing conditions. Only 18 of 203 sows behaved anxiously or aggressively. On average 9.1 piglets per sow and litter were weaned. Amongst the investigated farms, none was optimally managed. However, no plausible correlations between biological performance, animal health, human-animal relationship on the one hand and farm-specific production conditions (housing, management, feeding, watering) on the other hand were determined. It can therefore be deduced that the “success” or “failure” of the study farms can be attributed to the interaction of different factors rather than to individual production factors

Grain Size And Cap Layer Effects On Electromigration Reliability Of Cu Interconnects: Experiments And Simulation

This paper combined experiments and simulation to investigate the grain size and cap layer effects on electromigration (EM) reliability of Cu interconnects. First the statistical distribution of EM lifetime and failure modes were examined for in laid Cu interconnects of large and small grain structures with two different cap layers of SiCN vs. CoWP. The CoWP cap was found to significantly improve the EM lifetime due to the suppression of the interfacial mass transport as a result of strengthening of the Cu/cap interface bonding. In addition, the grain size was observed to affect the EM reliability significantly, particularly for the CoWP capped structures. Resistance traces and failure analysis revealed two distinct failure modes: mode I with voids formed near the cathode via corner and mode II with voids formed in the trench several microns away from the cathode via. It was found that large grain size and strong cap interface reduced the mass transport rate and the void diffusion in the Cu line, leading to a longer EM lifetime and a higher proportion of mode II failures. A statistical simulation of EM lifetimes was also applied to Cu interconnects with grain structures generated by the Monte Carlo method. The simulation results for different grain sizes and cap interfaces are in good agreement with the experimental observations.Microelectronics Research Cente

Increasing understanding of the relationship between geographic access and gendered decision-making power for treatment-seeking for febrile children in the Chikwawa district of Malawi

Background: This study used qualitative methods to investigate the relationship between geographic access and gendered intra-household hierarchies and how these influence treatment-seeking decision-making for childhood fever within the Chikwawa district of Malawi. Previous cross-sectional survey findings in the district indicated that distance from facility and associated costs are important determinants of health facility attendance in the district. This paper uses qualitative data to add depth of understanding to these findings by exploring the relationship between distance from services, anticipated costs and cultural norms of intra-household decision-making, and to identify potential intervention opportunities to reduce challenges experienced by those in remote locations. Qualitative data collection included 12 focus group discussions and 22 critical incident interviews conducted in the local language, with primary caregivers of children who had recently experienced a febrile episode. Results: Low geographic accessibility to facilities inhibited care-seeking, sometimes by extending the ‘assessment period’ for a child’s illness episode, and led to delays in seeking formal treatment, particularly when the illness occurred at night. Although carers attempted to avoid incurring costs, cash was often needed for transport and food. Whilst in all communities fathers were normatively responsible for treatment costs, mothers generally had greater access to and control over resources and autonomy in decision-making in the matrilineal and matrilocal communities in the central part of the district, which were also closer to formal facilities. Conclusions: This study illustrates the complex interplay between geographic access and gender dynamics in shaping decisions on whether and when formal treatment is sought for febrile children in Chikwawa District. Geographic marginality and cultural norms intersect in remote areas both to increase the logistical and anticipated financial barriers to utilising services and to reduce caretakers’ autonomy to act quickly once they recognize the need for formal care. Health education campaigns should be based within communities, engaging all involved in treatment-seeking decision-making, including men and grandmothers, and should aim to promote the ability of junior women to influence the treatment-seeking process. Both mothers’ financial autonomy and fathers financial contributions are important to enable timely access to effective healthcare for children with malaria

Discussing the Feasibility of Acoustic Sensors for Side Channel-aided Industrial Intrusion Detection: An Essay

The fourth industrial revolution leads to an increased use of embedded computation and intercommunication in an industrial environment. While reducing cost and effort for set up, operation and maintenance, and increasing the time to operation or market respectively as well as the efficiency, this also increases the attack surface of enterprises. Industrial enterprises have become targets of cyber criminals in the last decade, reasons being espionage but also politically motivated. Infamous attack campaigns as well as easily available malware that hits industry in an unprepared state create a large threat landscape. As industrial systems often operate for many decades and are difficult or impossible to upgrade in terms of security, legacy-compatible industrial security solutions are necessary in order to create a security parameter. One plausible approach in industry is the implementation and employment of side-channel sensors. Combining readily available sensor data from different sources via different channels can provide an enhanced insight about the security state. In this work, a data set of an experimental industrial set up containing side channel sensors is discussed conceptually and insights are derived