The Mason Test: A Defense Against Sybil Attacks in Wireless Networks Without Trusted Authorities

Wireless networks are vulnerable to Sybil attacks, in which a malicious node poses as many identities in order to gain disproportionate influence. Many defenses based on spatial variability of wireless channels exist, but depend either on detailed, multi-tap channel estimation - something not exposed on commodity 802.11 devices - or valid RSSI observations from multiple trusted sources, e.g., corporate access points - something not directly available in ad hoc and delay-tolerant networks with potentially malicious neighbors. We extend these techniques to be practical for wireless ad hoc networks of commodity 802.11 devices. Specifically, we propose two efficient methods for separating the valid RSSI observations of behaving nodes from those falsified by malicious participants. Further, we note that prior signalprint methods are easily defeated by mobile attackers and develop an appropriate challenge-response defense. Finally, we present the Mason test, the first implementation of these techniques for ad hoc and delay-tolerant networks of commodity 802.11 devices. We illustrate its performance in several real-world scenarios

A unified approach to nonlinearity, structural change and outliers

This paper demonstrates that the class of conditionally linear and Gaussian state-space models offers a general and convenient framework for simultaneously handling nonlinearity, structural change and outliers in time series. Many popular nonlinear time series models, including threshold, smooth transition and Markov-Switching models, can be written in state-space form. It is then straightforward to add components that capture parameter instability and intervention effects. We advocate a Bayesian approach to estimation and inference, using an efficient implementation of Markov Chain Monte Carlo sampling schemes for such linear dynamic mixture models. The general modelling framework and the Bayesian methodology are illustrated by means of several examples. An application to quarterly industrial production growth rates for the G7 countries demonstrates the empirical usefulness of the approach

Scheduled voltage scaling for increasing lifetime in the presence of NBTI

to an error at the time of submission and it was against the policy of the conference to later add him to the author list. Abstract — Negative Bias Temperature Instability (NBTI) is a leading reliability concern for integrated circuits (ICs). It gradually increases the threshold voltages of PMOS transistors, thereby increasing delay. We propose scheduled voltage scaling, a technique that gradually increases the operating voltage of the IC to compensate for NBTI-related performance degradation. Scheduled voltage scaling has the potential to increase IC lifetime by 46 % relative to the conventional approach using guard banding for ICs fabricated using a 45 nm process. I

Mechanistic Mode Connectivity

We study neural network loss landscapes through the lens of mode connectivity, the observation that minimizers of neural networks retrieved via training on a dataset are connected via simple paths of low loss. Specifically, we ask the following question: are minimizers that rely on different mechanisms for making their predictions connected via simple paths of low loss? We provide a definition of mechanistic similarity as shared invariances to input transformations and demonstrate that lack of linear connectivity between two models implies they use dissimilar mechanisms for making their predictions. Relevant to practice, this result helps us demonstrate that naive fine-tuning on a downstream dataset can fail to alter a model's mechanisms, e.g., fine-tuning can fail to eliminate a model's reliance on spurious attributes. Our analysis also motivates a method for targeted alteration of a model's mechanisms, named connectivity-based fine-tuning (CBFT), which we analyze using several synthetic datasets for the task of reducing a model's reliance on spurious attributes.Comment: Accepted at ICML, 202

Possible function of the protein bound to nuclear complementary RNA

It was demonstrated that individual renal endothelial dilatory function of the healthy rat predicts susceptibility to subsequent renal damage induced by 5/6 nephrectomy. In addition, it is reported that myocardial infarction (MI) that was performed upon unilateral nephrectomy (UNx) induced highly variable renal damage. Therefore, whether the variability in renal damage after MI could be explained by the variation in individual renal endothelial function before the induction of injury was studied. Endothelium-dependent relaxation to acetylcholine was investigated in vitro in small arteries that were isolated from the extirpated kidney at UNx. MI was induced 1 wk after UNx by ligation of the left coronary artery. Proteinuria and systolic BP were evaluated weekly for 16 wk thereafter using metabolic cages and the tail-cuff method, respectively. Upon termination of the study, focal glomerulosclerosis was evaluated by histology as an additional marker of renal damage. After MI, nephrectomized male Wistar rats (n = 15) gradually developed variable proteinuria, ranging from 20 to 507 mg/24 h at week 16, with an average systolic BP of 131 +/- 7 mmHg. The individual renal endothelial function of the healthy rats predicted the extent of renal damage in terms of proteinuria (r = -0.62, P = 0.008) and focal glomerulosclerosis (r = -0.70, P = 0.003). The individual level of renal endothelial function in the healthy rat is able to predict the severity of renal damage that is induced by MI. Further exploration of the underlying mechanisms may lead to discovery of preventive renoprotective therapies

The Ursinus Weekly, January 12, 1953

Petitions for May queen to start Feb. 2 • Revised final exam schedule • 11 students to graduate this January • Over 200 people hear Earle Spicer sing ballads Wed. • Lucas, Scott join cast of Alpha Psi • Pettit discovers fire in Bomberger chapel • Library has new collection of great books of western world • Campus Chest total is $955.23 • Y commission holds vespers • Frosh class discusses plans; Sets tentative dance date • Chem group to hear speech • Turkish speaker addresses classes Tuesday morning • Frats hold meetings, set date for dances • Movie to be shown in S-12 • 32 girls invited to Rosie dessert • Ruby wants snaps brought to Hobson • New rules regulate use of Alumni office machines • Editorials: New year suggestion • Goodbye H.S.T. • Letters to the editor • Engagements • Weddings • What are ex-student-teachers doing with their free time? • January graduates reveal variety of future plans • Resolutions of eager frosh contrast to humble seniors • F&M routs Bears 90-65 with second half splurge • Grizzlies rally to smother alumni 96-75 for fifth • Belles drub Moravian 75-22; Kuhn scores 21 • Grapplers down Swarthmore team • Herb Knull tabs record 46 as Ursinus routs Fords • French Club gives moviehttps://digitalcommons.ursinus.edu/weekly/1510/thumbnail.jp

Minimization of NBTI performance degradation using internal node control

Abstract—Negative Bias Temperature Instability (NBTI) is a significant reliability concern for nanoscale CMOS circuits. Its effects on circuit timing can be especially pronounced for circuits with standby-mode equipped functional units because these units can be subjected to static NBTI stress for extended periods of time. This paper proposes internal node control, in which the inputs to individual gates are directly manipulated to prevent this static NBTI fatigue. We give a mixed integer linear program formulation for an optimal solution to this problem. The optimal placement of internal node control yields an average 26.7 % reduction in NBTI-induced delay over a ten year period for the ISCAS85 benchmarks. We find that the problem is NP-complete and present a linear-time heuristic that can be used to quickly find near-optimal solutions. The heuristic solutions are, on average, within 0.17 % of optimal and all were within 0.60% of optimal. I