A Framework for Efficient Adaptively Secure Composable Oblivious Transfer in the ROM

Oblivious Transfer (OT) is a fundamental cryptographic protocol that finds a number of applications, in particular, as an essential building block for two-party and multi-party computation. We construct a round-optimal (2 rounds) universally composable (UC) protocol for oblivious transfer secure against active adaptive adversaries from any OW-CPA secure public-key encryption scheme with certain properties in the random oracle model (ROM). In terms of computation, our protocol only requires the generation of a public/secret-key pair, two encryption operations and one decryption operation, apart from a few calls to the random oracle. In~terms of communication, our protocol only requires the transfer of one public-key, two ciphertexts, and three binary strings of roughly the same size as the message. Next, we show how to instantiate our construction under the low noise LPN, McEliece, QC-MDPC, LWE, and CDH assumptions. Our instantiations based on the low noise LPN, McEliece, and QC-MDPC assumptions are the first UC-secure OT protocols based on coding assumptions to achieve: 1) adaptive security, 2) optimal round complexity, 3) low communication and computational complexities. Previous results in this setting only achieved static security and used costly cut-and-choose techniques.Our instantiation based on CDH achieves adaptive security at the small cost of communicating only two more group elements as compared to the gap-DH based Simplest OT protocol of Chou and Orlandi (Latincrypt 15), which only achieves static security in the ROM

Analytical approach to soliton ratchets in asymmetric potentials

We use soliton perturbation theory and collective coordinate ansatz to investigate the mechanism of soliton ratchets in a driven and damped asymmetric double sine-Gordon equation. We show that, at the second order of the perturbation scheme, the soliton internal vibrations can couple {\it effectively}, in presence of damping, to the motion of the center of mass, giving rise to transport. An analytical expression for the mean velocity of the soliton is derived. The results of our analysis confirm the internal mode mechanism of soliton ratchets proposed in [Phys. Rev. E {\bf 65} 025602(R) (2002)].Comment: 9 figures. Submitted to Phys. Rev.

Assessing the environmental and economic performance of alternative car chassis

The main objective of this study is to evaluate the life cycle environmental and economic performance of a car multimedia chassis containing metallic parts, and compare it with new, totally plastic, chassis designs. The Life Cycle Assessment and Life Cycle Costing methodologies were applied. All systems boundaries consider material and parts production, and the use and End of Life (EoL) phases of the chassis. The results showed that the former system has a higher environmental impact, the material production being the main contributor followed by the use phase, and Fossil depletion the most burdensome impact category. All total plastic scenarios enable approximately 40% weight reduction, mitigating both the Global Warming Potential and the Cumulative Energy Demand environmental impacts until the end of the use phase. However, this result is inverted including the EoL phase, as recycling the metal is more favourable than incinerating the polymer and recovering energy. All TPC scenarios present a higher cost. Although their assembly and use phases costs are lower than the corresponding BSL ones, this does not mitigate the higher material and production costs. Again, at EoL, recycling the metal is more cost favourable. The present work evidences that to make sustainable decisions environmental and economic considerations should be concurrently contemplated in product development.The present work was partially financed by the Portuguese Incentive System for Research and Technological Development, as co-promotion Project nº 36265/2013 (Project HMIExcel – 2013-2015). The authors thank the support of the Bosch Car Multimedia Portugal, S.A. company throughout the inventory phase of the study. Two of the authors (CAB, AJP) acknowledge the funding received from FCT, the Portuguese Foundation for Science and Technology, through project UID/CTM/50025/2013 and from the COMPETE 2020 Programme under project POCI-01-0145-FEDER-00768

Evaluation of cyclone geometry and its influence on performance parameters by computational fluid dynamics (CFD)

Cyclone models have been used without relevant modifications for more than a century. Most of the attention has been focused on finding new methods to improve performance parameters. Recently, some studies were conducted to improve equipment performance by evaluating geometric effects on projects. In this work, the effect of cyclone geometry was studied through the creation of a symmetrical inlet and a volute scroll outlet section in an experimental cyclone and comparison to an ordinary single tangential inlet. The study was performed for gas-solid flow, based on an experimental study available in the literature, where a conventional cyclone model was used. Numerical experiments were performed by using CFX 5.7.1. The axial and tangential velocity components were evaluated using RSM and LES turbulence models. Results showed that these new designs can improve the cyclone performance parameters significantly and very interesting details were found on cyclone fluid dynamics properties using RSM and LES.839

Maximum Entropy and Bayesian Data Analysis: Entropic Priors

The problem of assigning probability distributions which objectively reflect the prior information available about experiments is one of the major stumbling blocks in the use of Bayesian methods of data analysis. In this paper the method of Maximum (relative) Entropy (ME) is used to translate the information contained in the known form of the likelihood into a prior distribution for Bayesian inference. The argument is inspired and guided by intuition gained from the successful use of ME methods in statistical mechanics. For experiments that cannot be repeated the resulting "entropic prior" is formally identical with the Einstein fluctuation formula. For repeatable experiments, however, the expected value of the entropy of the likelihood turns out to be relevant information that must be included in the analysis. The important case of a Gaussian likelihood is treated in detail.Comment: 23 pages, 2 figure

Modeling and Analysis of Power-Aware Systems

The paper describes a formal approach for designing and reasoning about power-constrained, timed systems. The framework is based on process algebra, a formalism that has been developed to describe and analyze communicating concurrent systems. The proposed extension allows the modeling of probabilistic resource failures, priorities of resource usages, and power consumption by resources within the same formalism. Thus, it is possible to model alternative power-consumption behaviors and analyze tradeoffs in their timing and other characteristics. This paper describes the modeling and analysis techniques, and illustrates them with examples, including a dynamic voltage-scaling algorithm

Diaphragmmatic eventration: long-term follow-up and results of open-chest plicature

Objective: Diaphragmmatic eventration is a relatively uncommon entity with a simple surgical correction technique - plication of the diaphragm. This study aims to assess the clinical and ventilatory impact of this technique. Materials: From April 1988 to February 2007, we operated on 20 patients (12 men) with diaphragmmatic eventration using the postero-lateral approach and correction by radial plication. The mean age of the patients studied was 56.3+/-15.6 years (range: 13-74 years). A traumatic cause was identified in 13 patients; one patient had a congenital cause and the remainder were of idiopathic origin. Chronic obstructive pulmonary disease and arterial hypertension were present in one-half of the study group, while diabetes mellitus was present in three patients. Dyspnoea was the most common complaint in 75% of the patients, and thoracic pain was present in 25%. The mean forced expiratory volume in 1s (FEV(1)) and vital capacity (VC) were 66.2+/-15.3% and 70.4+/-16% of the predicted values, respectively. Results: There was no operative mortality. Apart from a patient with moderate/severe pain and another who had pneumonia, there were no other important perioperative complications. Average drainage time was 3.3+/-1.6 days (range: 2-7 days). Hospitalisation time was 6.2+/-1.6 days (5-10 days). Follow-up was complete, for a mean of 59.6+/-55.1 months (4-206 months). There were three late deaths (one sudden, one stroke and one trauma). Eight of the 17 survivors (47%) are asymptomatic. According to the MRC/ATS grading system, the dyspnoea score was 2.06+/-0.97 preoperatively and 1.06+/-1.14 postoperatively (p=0.007). At follow-up, the FEV(1) was 76.1+/-20.1% and the VC was 78.4+/-17.3% (p>0.1). Two patients had chronic pain. Conclusion: Plication of the diaphragm is a safe and efficient procedure. Most patients experienced significant clinical improvement with enhancement of the FEV(1) and VC. Chronic surgical pain still remains a potential problem with the classical approach

Reference priors for high energy physics

Bayesian inferences in high energy physics often use uniform prior distributions for parameters about which little or no information is available before data are collected. The resulting posterior distributions are therefore sensitive to the choice of parametrization for the problem and may even be improper if this choice is not carefully considered. Here we describe an extensively tested methodology, known as reference analysis, which allows one to construct parametrization-invariant priors that embody the notion of minimal informativeness in a mathematically well-defined sense. We apply this methodology to general cross section measurements and show that it yields sensible results. A recent measurement of the single top quark cross section illustrates the relevant techniques in a realistic situation