Circuit Theory

Contains a report on a research project

Stroboscopic Reasearch

Contains reports on one research project

Barriers That Influence Adoption of ACL Injury Prevention Programs Among High School Girls’ Soccer Coaches

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Proposed classification scheme for high-level and other radioactive wastes

The Nuclear Waste Policy Act (NWPA) of 1982 defines high-level radioactive waste (HLW) as: (A) the highly radioactive material resulting from the reprocessing of spent nuclear fuel....that contains fission products in sufficient concentrations; and (B) other highly radioactive material that the Commission....determines....requires permanent isolation. This paper presents a generally applicable quantitative definition of HLW that addresses the description in paragraph (B). The approach also results in definitions of other waste classes, i.e., transuranic (TRU) and low-level waste (LLW). A basic waste classification scheme results from the quantitative definitions

CacheZoom: How SGX Amplifies The Power of Cache Attacks

In modern computing environments, hardware resources are commonly shared, and parallel computation is widely used. Parallel tasks can cause privacy and security problems if proper isolation is not enforced. Intel proposed SGX to create a trusted execution environment within the processor. SGX relies on the hardware, and claims runtime protection even if the OS and other software components are malicious. However, SGX disregards side-channel attacks. We introduce a powerful cache side-channel attack that provides system adversaries a high resolution channel. Our attack tool named CacheZoom is able to virtually track all memory accesses of SGX enclaves with high spatial and temporal precision. As proof of concept, we demonstrate AES key recovery attacks on commonly used implementations including those that were believed to be resistant in previous scenarios. Our results show that SGX cannot protect critical data sensitive computations, and efficient AES key recovery is possible in a practical environment. In contrast to previous works which require hundreds of measurements, this is the first cache side-channel attack on a real system that can recover AES keys with a minimal number of measurements. We can successfully recover AES keys from T-Table based implementations with as few as ten measurements.Comment: Accepted at Conference on Cryptographic Hardware and Embedded Systems (CHES '17

Social preferences, accountability, and wage bargaining

We assess the extent of preferences for employment in a collective wage bargaining situation with heterogeneous workers. We vary the size of the union and introduce a treatment mechanism transforming the voting game into an individual allocation task. Our results show that highly productive workers do not take employment of low productive workers into account when making wage proposals, regardless of whether insiders determine the wage or all workers. The level of pro-social preferences is small in the voting game, while it increases as the game is transformed into an individual allocation task. We interpret this as an accountability effect

Cache Based Power Analysis Attacks on AES

International audienceThis paper describes possible attacks against software implementations of AES running on processors with cache mechanisms, particularly in the case of smart cards. These attacks are based on sidechannel information gained by observing cache hits and misses in the current drawn by the smart card. Two dierent attacks are described. The first is a combination of ideas proposed in [2] and [11] to produce an attack that only requires the manipulation of the plain text and the observation of the current. The second is an attack based on specific implementations of the xtime function [10]. These attacks are shown to also work against algorithms using Boolean data masking techniques as a DPA countermeasure

On the automatic construction of indistinguishable operations

An increasingly important design constraint for software running on ubiquitous computing devices is security, particularly against physical methods such as side-channel attack. One well studied methodology for defending against such attacks is the concept of indistinguishable functions which leak no information about program control flow since all execution paths are computationally identical. However, constructing such functions by hand becomes laborious and error prone as their complexity increases. We investigate techniques for automating this process and find that effective solutions can be constructed with only minor amounts of computational effort.Fundação para a Ciência e Tecnologia - SFRH/BPD/20528/2004

Monitoring and Pay: An Experiment on Employee Performance under Endogenous Supervision

We present an experimental test of a shirking model where monitoring intensity is endogenous and effort a continuous variable. Wage level, monitoring intensity and consequently the desired enforceable effort level are jointly determined by the maximization problem of the firm. As a result, monitoring and pay should be complements. In our experiment, between and within treatment variation is qualitatively in line with the normative predictions of the model under standard assumptions. Yet, we also find evidence for reciprocal behavior. Our data analysis shows, however, that it does not pay for the employer to solely rely on the reciprocity of employees

A Comparison of Three Xylanases on the Nutritive Value of Two Wheats for Broiler Chickens

Three xylanase products, xylanase A derived from Thermomyces lanuginosus, xylanase B from Humicola insolens and xylanase C from Aspergillus aculeatus, were examined for their effects on the nutritive value of wheat. The study investigated the effects of enzyme addition to broiler diets based on a low-metabolisable-energy (ME) wheat and a normal-ME wheat, with the emphasis on changes in composition of the NSP along the digestive tract in broiler chickens. There were significant (P>0.01) enzyme and wheat effects on the apparent ME, but there was no wheat X enzyme interaction on apparent ME. Weight gain and feed conversion efficiency (except xylanase C for normal wheat) were also significantly (P>0.01) increased by the xylanases. The enzymes differed in their effect on a number of important nutritional parameters. Xylanase A reduced (P>0.05) the excreta moisture level from 77.1% in birds fed the normal-ME wheat control to 73.4% and from 77.4% in those fed the low-ME wheat to 73.0%. The other two enzymes did not affect excreta moisture levels. The digesta viscosity in the duodenum, jejunum and ileum of birds fed both types of wheat was reduced (P>0.01) by xylanases A and C, but was increased (P>0.01) in the jejunum and ileum by xylanase B. The digestibility of the soluble NSP was mostly negative in the small intestine. The digestibility of the insoluble NSP differed (P>0.01) between the two wheats, with those in the low-ME wheat being more digestible (14 v. 28%). When supplemented with xylanase A, the ileal digestibility of the insoluble NSP in the normal- and low-ME wheats was increased by 28 and 42%, respectively. Xylanases B and C did not affect the digestibility of the insoluble NSP regardless of wheat type. It may be concluded that wheats with low or normal ME values vary in their responses to xylanase supplementation. Apart from having an elevated level of soluble NSP, low-ME wheat may also contain insoluble NSP, which in the present study appeared to be more easily degradable in the gut of the chicken