A Simpler Construction of CCA2-Secure Public-Key Encryption under General Assumptions

In this paper we present a simpler construction of a public-key encryption scheme that achieves adaptive chosen ciphertext security (CCA2), assuming the existence of trapdoor permutations. We build on previous works of Sahai and De Santis et al. and construct a scheme that we believe is the easiest to understand to date. In particular, it is only slightly more involved than the Naor--Yung encryption scheme that is secure against passive chosen-ciphertext attacks (CCA1). We stress that the focus of this paper is on simplicity only.     

Binding Energies of Aromatic 1:1 Hetero-Clusters in a Supersonic Jet

Methods used to experimentally estimate the binding energies of van der Waals clusters containing an aromatic molecule are surveyed. These include microwave and infrared absorption spectroscopies, single and two photon ionization, dispersed fluorescence, and stimulated emission pumping. The problems encountered in the application of these methods are briefly discussed, and prospects for the firm establishment of the binding energies are assessed. Although the present database is too small for firm conclusions, methods based on dispersed fluorescence (i.e., probing the excited state surface) tend to yield lower values for argon adducts than those based on ionization, probing the ground state, or ionic surfaces. A mechanism that may account for this tendency is proposed, and further experiments are proposed to test it.     

Analysis of bandgap characteristics of two-dimensional periodic structures by using the source-model technique

We introduce a solution based on the source-model technique for periodic structures for the problem of electromagnetic scattering by a two-dimensional photonic bandgap crystal slab illuminated by a transverse-magnetic plane wave. The proposed technique takes advantage of the periodicity of the slab by solving the problem within the unit cell of the periodic structure. The results imply the existence of a frequency bandgap and provide a valuable insight into the relationship between the dimensions of a finite periodic structure and its frequency bandgap characteristics. A comparison shows a discrepancy between the frequency bandgap obtained for a very thick slab and the bandgap obtained by solving the corresponding two-dimensionally infinite periodic structure. The final part of the paper is devoted to explaining in detail this apparent discrepancy.     

Topological fisheye views for visualizing large graphs

Graph drawing is a basic visualization tool that works well for graphs having up to hundreds of nodes and edges. At greater scale, data density and occlusion problems often negate its effectiveness. Conventional pan-and-zoom, multiscale, and geometric fisheye views are not fully satisfactory solutions to this problem. As an alternative, we propose a topological zooming method. It precomputes a hierarchy of coarsened graphs that are combined on-the-fly into renderings, with the level of detail dependent on distance from one or more foci. A related geometric distortion method yields constant information density displays from these renderings.     

Similarities and differences in block design performance between older normal and brain-injured persons: A task analysis.

Developed an objective scoring system to determine whether right and left hemiplegics differ from normal controls, and from one another, in terms of competence levels, style of performance, constructional deviations, and various rates of activity while attempting to solve block designs. A microanalysis of the wais block design performances of 40 normals, 56 right hemiplegics, and 49 left hemiplegics was conducted. Results indicate that (a) brain-injured ss were inferior to normals in competence, (b) brain-injured ss did not differ from normals in style of performance and in partial competence, (c) right hemiplegic ss differed from left hemiplegic ss on all parameters of performance but competence level. Theoretical and clinical implications are discussed. (29 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Modelling polyhedral solids bounded by multi-curved parametric surfaces

Since the beginning of geometric modelling as a field of CAD a decade ago, the methods for interactive design of solid objects and interactive design of free-formed surfaces (of degree three and higher) were developed along parallel yet disjoint lines. One led to the development of techniques for representing and manipulating the shape of polyhedral solids bounded mostly by planes, while the other led to the development of techniques for the mathematical representation of curved surfaces, without paying attention to their combination into volumetric solids. Though the need for integrating solid object modelling with surface modelling for the design of such artefacts as machine parts, aircraft, cars and ships has been widely recognized, there is so far no single modelling system which provides such capabilities in a general way.An integrated solids modelling system for representing and manipulating polyhedral objects bounded by bicubic parametric surfaces is presented. Its basic capabilities include the representation of solids through a surface-based model, such that the surface underlying any face can be replaced by another surface that has been modelled independently. Other functionalities include scaling, rotation and translation of shapes and their pairwise combination into more complex shapes by means of spatial set operators.     

Stress-induced suppression of natural killer cell cytotoxicity in the rat: A naltrexone-insensitive paradigm.

The suppression of natural killer (NK) cell cytotoxicity by footshock stress can be attenuated by opioid antagonists, implicating endogenous opioids in its mediation. A stress paradigm that includes NK suppression that is not blocked by the opioid antagonist naltrexone is reported. This stress paradigm is also shown to cause analgesia and elevated plasma corticosterone levels that are not attenuated by naltrexone. In the first experiment, a significant suppression of NK cell cytotoxicity after forced swimming was demonstrated in Fischer 344 rats treated with either saline or naltrexone, compared with nonstressed controls. Significantly higher corticosterone levels were evident in both stressed groups. In the second experiment, the same stress paradigm was shown to cause significant analgesia in the tail-flick test. It is concluded that opioids need not always be involved in the suppression of NK cell cytotoxicity by stress. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A method for evaluating activities layout in dwelling units

A method for evaluating the quality of a layout of activities in dwelling units presented. The method is based upon the analysis of the mutual spatial relations between the locations of the activities. The components of the connection between activities which are privacy, affinity and disturbance are analysed as well, and are represented in a vector form. A general space of mutual relations between the locations of activities is defined. Correspondence between the vectors representing connections and elements of the space of mutual relations is formulated. This correspondence provides a key for evaluation of dwelling units. A detailed case study is given.     

Peer nomiations as a predictor of multistage promotions in a ramified organization.

Studied the validity of peer nominations (PNs) as a predictor of advancement in rank in the Israel Defense Forces on a population of 125 platoons encompassing 3897 soldiers. Results indicate that PNs obtained at early stages of training predicted promotion at several successive stages in the soldier's military career with a high degree of validity and correlations generally around .6 and .7. Predictions were valid for success within groups of different personnel, and with different purposes, and criteria for achievement. PNs were also found to contribute markedly to the predictive validity of conventional psychological screening measures, suggesting the value of combining psychometric and sociometric procedures for personnel selection. (16 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Computerized design and economic evaluation of an aqua-ammonia solar operated absorption system

A computerized simulation and design of solar operated NH₃---H₂O absorption refrigeration cycles is presented. The program receives input data and calculates the building, cooling and heating loads initially. Next the absorption cycle is designed along with the solar collectors and auxiliaries. Various economic parameters are also calculated from which the most favorable system may be selected. Two examples were run: one for the Knesset building in Jerusalem (Israeli parliament) and the other for an American office building. Results indicate the existence of various mininal operating parameters, e.g. collectors' outlet temperature, etc. For the Knesset building some 46 per cent of the annual heating and cooling demand may be provided by the solar system. At the 1979 rate of energy cost increase in Israel the system payback period was estimated at 9 yr with a present value total saving of $42.5 m. Yet higher values were obtained for the American office building at about 81 per cent solar fraction for the compound cooling and heating system.