Power Side Channels in Security ICs: Hardware Countermeasures

Power side-channel attacks are a very effective cryptanalysis technique that can infer secret keys of security ICs by monitoring the power consumption. Since the emergence of practical attacks in the late 90s, they have been a major threat to many cryptographic-equipped devices including smart cards, encrypted FPGA designs, and mobile phones. Designers and manufacturers of cryptographic devices have in response developed various countermeasures for protection. Attacking methods have also evolved to counteract resistant implementations. This paper reviews foundational power analysis attack techniques and examines a variety of hardware design mitigations. The aim is to highlight exposed vulnerabilities in hardware-based countermeasures for future more secure implementations

Understanding Older Vehicle Users: An Interpretative Approach

Future adaptations in vehicle design should be linked in some parts to the age-related changes often faced by the older users. The aim of this research is to investigate the multiple age-related changes of Chinese older vehicle users in order to assist designers to better understand current and future older users’ needs. Although qualitative interpretative approaches have rarely been applied in the field of traffic gerontology research, they are widely used in current design research to explore persons’ lived experiences, behaviours and emotions. Therefore, this study employed qualitative research methods consisting of observation, interview, travel logbook and co-discovery to explore older vehicle users’ travel needs. The interpretative analysis confirmed that multiple methods such as interview, travel logbook, and co-discovery are useful to gain a holistic understanding of older drivers’ travel needs. However, the one journey driving observation cannot provide valuable categories to explore older users’ multiple travel needs due to daily living context absence in the one trip experiment. It is clear that the useful methods for determining research for older users will depend on the product. The findings demonstrate that Chinese future older generations are more concerned about their age-related differences from social and cultural perspective rather than physiological perspective. Social and cultural context play important role to shape older vehicle users’ future travel needs. From design a point of view, understanding the social activity and cultural context surrounds older vehicle users should make it possible to predict older drivers’ needs related to vehicle property. Keywords: Older Vehicle Users; Cultural Context; Social Context; Vehicle Design; Qualitative Research</p

Stock Price Reaction to Dividend Changes: An Empirical Test

This paper investigates both long-term and short-term stock price reactions to announcements of dividend changes. We document that short-term abnormal returns surrounding dividend increases are more significant than those surrounding dividend decreases. In the long run, the mean monthly calendar time abnormal returns following dividend increases are positively significant, suggesting underreaction. Yet no long-term post-event abnormal returns are observed for dividend decreases. Examining subsamples sorted by market value of equity and percentage dividend change, respectively, we notice that the magnitude of percentage dividend changes is positively correlated with that of absolute abnormal returns, and firms of smaller size produce more apparent abnormal returns than do those of bigger size

On The Leakage and Rotordynamic Force Coefficients of Pump Annular Seals Operating with Air/Oil Mixtures: Measurements and Predictions

LecturesIn the subsea oil and gas industry, multiphase pumps and wet gas compressors add pressure to the process fluid thus enabling long distance tie back system that eliminates topside facilities such as an oil and gas separation station. One challenge to construct a reliable multiphase pump or a wet gas compressor is to engineer their ability to withstand a gas-liquid mixture whose gas volume fraction (GVF) or liquid volume fraction (LVF) changes over time. The mixture GVF or LVF affects the static and dynamic forced performance of secondary flow components, namely seals, and which may lead to an increase in both rotor lateral or axial vibrations. The lecture presents measurements of leakage and dynamic force coefficients for six annular seals (see Fig. 1, L = 46 mm, D = 127 mm) for multiple-stage submersible pumps and operating with an air in oil mixture ranging from pure liquid to just air. Each seal has a distinct clearance configuration: one is a plain seal with a small clearance (c=0.203 mm), and another has a larger (worn) clearance (c=0.274 mm); a third seal introduces a wavy clearance (cm= 0.191 mm) that produces a significant centering stiffness; a fourth seal has a shallow groove pattern (cr=0.211); and the fifth seals have a stepped clearance (narrow to wide and wide to narrow). At a shaft speed of 3.5 krpm, an air in ISO VG 10 oil mixture with an inlet GVF varying discretely from 0 to 0.9 feeds a test seal at a supply pressure Ps of 2.5 bar(a). The test mixture mass flow rate decreases continuously with an increase in the inlet GVF. The seals Copyright© 2018 by Turbomachinery Laboratory, Texas A&M Engineering Experiment Station 2 operating with a pure liquid (GVF=0) show frequency independent force coefficients. On the other hand, operation with a mixture produces direct and cross-coupled stiffnesses that vary greatly with frequency, in particular the direct stiffness hardens with excitation frequency. The direct damping coefficients, on the other hand, are not functions of excitation frequency, albeit dropping rapidly in magnitude as the GVF increases. The lecture details comparisons of leakage and force coefficients among the various test seals. The three-wave seal produces the greatest direct stiffness and damping coefficients, as well as the largest effective damping coefficient. The worn surface (largest clearance) seal produces the smallest force coefficients and leaks the most. Operation with a large GVF produces little damping, albeit more than predicted. For all the test seals, the whirl frequency ratio is around 50%. The step clearance seal (with the narrow clearance facing the incoming flow produces a significant negative direct stiffness that could easily impact the static stability of a pump as it reduces its natural frequency. Predictions of seal force coefficients derived from a homogeneous bulk flow match well with the test data for operation with a pure oil and a small GVF ~ 0.2. The discrepancy between the prediction and test data grows rapidly for operation with a larger gas content, GVF > 0.2. Hence, more accurate predictive models are in urgent need of development. The experimental results reveal the best characteristics of certain annular seal configurations, thus aiding to better design and understand the operation of centrifugal pumps handing multiple-phase flows

Leakage and Force Coefficients for Pump Annular Seals Operating With Air/Oil Mixtures: Measurements Vs Predictions and Air Injection to Increase Seal Dynamic Stiffness

LectureThe lecture presents measurements of leakage and dynamic force coefficients for six annular seals operating with an air in oil mixture ranging from pure liquid to just air. Each seal has a distinct clearance configuration: one is a plain seal with a small clearance, and another has a larger (worn) clearance ; a third seal introduces a wavy clearance that produces a significant centering stiffness; a fourth seal has a shallow groove pattern ; and the fifth and sixth seals have a stepped clearance (narrow to wide and wide to narrow). The tests in a plain seal supplied with gas injection (GVF~0?0.6) in the oil stream demonstrate the seal recovers its dynamic stiffness, hence its usage to recover rotor stability. Air injection into a liquid stream drops the mixture sound speed to make it highly compressible; hence the hardening of the seal direct stiffness

Joint Communication and Sensing in RIS-enabled mmWave Networks

Empowering cellular networks with augmented sensing capabilities is one of the key research areas in 6G communication systems. Recently, we have witnessed a plethora of efforts to devise solutions that integrate sensing capabilities into communication systems, i.e., joint communication and sensing (JCAS). However, most prior works do not consider the impact of reconfigurable intelligent surfaces (RISs) on JCAS systems, especially at millimeter-wave (mmWave) bands. Given that RISs are expected to become an integral part of cellular systems, it is important to investigate their potential in cellular networks beyond communication goals. In this paper, we study mmWave orthogonal frequency-division multiplexing (OFDM) JCAS systems in the presence of RISs. Specifically, we jointly design the hybrid beamforming and RIS phase shifts to guarantee the sensing functionalities via minimizing a chordal-distance metric, subject to signal-to-interference-plus-noise (SINR) and power constraints. The non-convexity of the investigated problem poses a challenge which we address by proposing a solution based on the penalty method and manifold-based alternating direction method of multipliers (ADMM). Simulation results demonstrate that under various settings both sensing and communication experience improved performance when the RIS is adequately designed. In addition, we discuss the tradeoff between sensing and communication