Partial Fairness in Secure Two-Party Computation

A protocol for secure computation is fair if either both parties learn the output or else neither party does. A seminal result of Cleve (STOC ’86) is that, in general, complete fairness is impossible to achieve in two-party computation. In light of this, various techniques for obtaining partial fairness have been suggested in the literature. We propose a definition of partial fairness within the standard real-/ideal-world paradigm. We also show broad feasibility results with respect to our definition: partial fairness is possible for any (randomized) functionality f:X×Y→Z ¹×Z ² at least one of whose domains or ranges is polynomial in size. Our protocols are always private, and when one of the domains has polynomial size our protocols also achieve the usual notion of security with abort. We work in the standard communication model (in particular, we do not assume simultaneous channels) and, in contrast to some prior work, rely only on standard cryptographic assumptions (e.g., enhanced trapdoor permutations).     

Model‐based guidelines for user‐centric satellite control software development

Three persistent common problems in satellite ground control software are obsolescence, lack of desired features and flexibilities, and endless software bug fixing. The obsolescence problem occurs when computer and ground equipment hardware become obsolete, usually after only one‐third into the satellite mission lifetime. The software needs to be updated to accommodate changes on the hardware side, requiring significant work of satellite operators to test, verify, and validate these software updates. Trying to help solve these problems, we have proposed an object‐process methodology model and guidelines for developing satellite ground control software. The system makes use of a database‐driven application and concepts of object‐process orientation and modularity. In the new proposed framework, instead of coding each software function separately, the common base functions will be coded, and combining them in various ways will provide the different required functions. The formation and combination of these base functions will be governed by the main code, definitions, and database parameters. These design principles will make sure that the new software framework would provide satellite operators with the flexibility to create new features and enable software developer to find bugs quicker and fix them more effectively. Copyright © 2015 John Wiley & Sons, Ltd.     

Energy considerations in crack deflection phenomenon in single crystal silicon

Crack deflection in single-crystal brittle occurs when a crack, propagating on one cleavage plane, ‘chooses’, from energy considerations, to continue propagating on another cleavage plane. This phenomenon was identified during dynamic crack propagation experiments of thin, rectangular [0 0 1] single-crystal (SC) silicon specimens subjected to three-point bending (3PB). Specimens with long pre-cracks (hence propagating at a ‘low’ energy and velocity) cleave along the vertical (1 1 0) plane, while the same specimens but with short pre-cracks (and therefore with higher propagation energy and velocity) cleave along the inclined (1 1 1) plane. The same specimens with intermediate pre-crack length show that the crack first propagates on the (1 1 0) plane and then deflects to the (1 1 1) plane. We show that the deflection is due to variations of the material property that resists cracking, Γ, the dynamic cleavage energy, with velocity and crystallographic orientation. We propose selection criteria to explain the deflection: The crack will deflect to the plane with the lowest dynamic cleavage energy. We further suggest that crack deflection is the basic mechanism controlling the way the crack consumes energy while propagating and is the main cause of surface perturbations. The spatial temporal fracture energy along the (1 1 0) cleavage plane is evaluated.     

Determining production sequences for single-stage multifunctional machining systems based on the tradeoff between fixture cost, re-fixturing and tool replenishment

The main advantage of a Single-Stage Multifunctional machining System (SSMS) is its ability to combine many operations and processes, previously done on different machines in several stages, into a single stage. The flexibility and process variety these machining systems offer have ensured their widespread adoption in industry. As a result SSMSs frequently constitute the bottleneck of a manufacturing system and therefore control system throughput. Hence, it is imperative to use these resources efficiently. This study considers three possible costs and the tradeoffs between them that are pertinent to any job sequence: (i) the Tool Magazine Replenishment (TMR) cost; (ii) the Re-Fixturing (RF) cost; and (iii) the fixture cost. A job sequencing algorithm that minimizes these costs as well as the machine non-operational time, which stems from TMRs and RFs, is developed. The algorithm takes into account the tools and fixture requirements as well as the tool magazine capacity. The algorithm also recommends purchasing additional fixtures when economically justified. The algorithm is used to solve a job sequencing problem that occurs in a real industrial setting.     

Chemorheological changes in crosslinked epoxy resins subjected to large strains

Chemorheological changes in epoxy resins subjected to large strains while heated were observed earlier, but the subject was not treated quantitatively. This paper describes the investigation of an epoxy resin—Epon 826, of known chemical, structure, crosslinked with two different amines. By means of a simple calibrated apparatus, the epoxide samples were subjected to large strains in a non-oxidizing atmosphere and in air. They were heated to different temperatures for various times; the results were compared with data obtained from unstrained samples kept in otherwise the same conditions. The results show a linear-logarithmic relation between the torsion modulus, G₍₁₀₎ and the time of applied strain at a certain temperature and also a linear relation between G₍₁₀₎, and 1/T°K, both above T₍₁₀₎. The results obtained in swelling experiments support the data from 10 sec torsional modulus vs temperature measurements. An increase in the amount of solubles and in M_c is observed on extending the time of heating. A clear difference in properties between the strained and unstrained samples, kept in otherwise the sane conditions, is observed and the contribution of the applied strain to chemorheology has been shown. Both systems of crosslinked Epon 826 showed the same general behavior, although the specific data were different.     

An equivalent pressure source for the heart

A technique is described for the representation of the left ventricle as a one-port source characterized by a generator pressure and an internal impedance. The Fourier components of the pressure and impedance are determined from phasor analysis performed on recorded time-domain functions of pressure and flow under two conditions of loading. One condition is the quiescent state corresponding to normal operation of the circulatory system, and the other is obtained by use of a phase-shift balloon pump situated in the descending thoracic aorta. The use of the balloon pump for determining source parameters is novel. The Fourier components of pressure and impedance are determined for the first five harmonics of the quiescent pulse rate. Heart failure is simulated by ligation of all branches of the anterior descending coronary artery. The source parameters have been found to vary considerably between normal and failing hearts. Valve impedance and the impedance at the root of the aorta were also measured. The generator time-domain pressure waveforms were determined from the Fourier components. Effects of long duration pumping, upon the source parameters were found. The ratio of the calculated magnitudes of internal to external or load impedance indicates the possibility of considering the heart as a pressure source.     

Reduction of the incidence of postharvest quality losses,and future prospects

Both quantitative and qualitative food losses of extremely variable magnitude occur during all harvest and postharvest stages, from harvesting, through handling, storage, processing and marketing, to final delivery to the consumer. The latest values published indicated that industrialized and developing countries dispose of roughly similar quantities of food. Whereas in developed countries the losses occur at the retailer and consumer stages, in the developing countries the losses occur during the production, harvest, postharvest and processing phases, because of poor infrastructure, low levels of technology, and low investment in food production systems. Quality cannot be improved after harvest, only maintained; therefore it is important to harvest fruits, vegetables and flowers at the proper stage and size and at peak quality. Preharvest production practices and factors such as cultivation practices, water supply, type of soil, environmental temperature and mechanical damage may seriously affect postharvest quality and result in the rejection or downgrading of produce at the point of sale. In addition, after harvest, improper temperature and humidity management as well as packaging and handling may have adverse effects on storage life and quality. Thus, integration of treatment methods calls for specific differential combinations of treatments for each product in each country.     

Molecular circuits for associative learning in single-celled organisms

We demonstrate how a single-celled organism could undertake associative learning. Although to date only one previous study has found experimental evidence for such learning, there is no reason in principle why it should not occur. We propose a gene regulatory network that is capable of associative learning between any pre-specified set of chemical signals, in a Hebbian manner, within a single cell. A mathematical model is developed, and simulations show a clear learned response. A preliminary design for implementing this model using plasmids within Escherichia coli is presented, along with an alternative approach, based on double-phosphorylated protein kinases.