18888101
Validation of Elliptic Curve Public Keys
We present practical and realistic attacks on some standardized elliptic curve key establishment and public-key encryption protocols that are effective if the receiver of an elliptic curve point does not check that the point lies on the appropriate elliptic curve. The attacks combine ideas from the small subgroup attack of Lim and Lee, and the differential fault attack of Biehl, Meyer and Muller. Although the ideas behind the attacks are quite elementary, and there are simple countermeasures known, the attacks can have drastic consequences if these countermeasures are not taken by implementors of the protocols. We illustrate the effectiveness of such attacks on a key agreement protocol recently proposed for the IEEE 802.15 Wireless Personal Area Network (WPAN) standard.
40941890
The Quadrangulation Conjecture for Orientable Surfaces
By means of character theory and symmetric functions, D. M. Jackson and T. I. Visentin (1990, Trans. Amer. Math. Soc. 322, (343-363)) proved the existence of certain bijections between the set of quadrangulations in orientable surfaces and decorated maps (with marked edges and coloured vertices) in orientable surfaces. The bijections preserve a weight function consisting of a pair (g,n) of integer parameters. For quadrangulations, g is the genus and n is the number of faces. For decorated maps, g is the genus plus half the number of white vertices and n is the number of edges. The Quadrangulation Conjecture concerns the problem of finding a natural bijection of this type. Tutte's medial construction is a solution in the special case g = 0 of planar maps. We give a construction of a bijection ??Ξ which both extends Tutte's medial construction to non-planar maps and preserves the parameter n of the Quadrangulation Conjecture. (The parameter g is not generally preserved, except when g = 0.) Non-orientable surfaces play an important part in the construction of ??Ξ. As part of the construction, we introduce a bijection between orientable rooted quadrangulations and locally orientable, bipartite, rooted quadrangulations.
28079143
Provably Secure Implicit Certificate Schemes
Optimal mail certificates, introduced in [12], are efficient types of implicit certificates which offer many advantages over traditional (explicit) certificates. For example, an optimal mail certificate is small enough to fit on a two-dimensional digital postal mark together with a digital signature. This paper defines a general notion of security for implicit certificates, and proves that optimal mail certificates are secure under this definition.
1252083
Formal Security Proofs for a Signature Scheme with Partial Message Recovery
The Pintsov-Vanstone signature scheme with partial message recovery (PVSSR) is a signature scheme with low message expansion (overhead) and variable length recoverable and non-recoverable message parts. The scheme uses three cryptographic primitives: a symmetric cipher, hash function and an elliptic curve group. We give three security proofs for PVSSR in this paper. Each proof makes a concrete and necessary assumption about one primitive, and models the other two primitives by idealizations. Thus, PVSSR with a strong cipher may offer greater security than other common variants of ElGamal signatures.
6315058
Knowledge and Control for a Mechanical Design Expert System
A new variety of Oriental hybrid lily plant bearing large upright-facing flowers particularly characterized by their clear pink coloration with deeper midribs, their large size and substance, and their upright to semi-upright orientation, the flowers being of excellent form and long persistence both on the plant and as cut flowers. This combination is completely new in the Oriental hybrid divisions of lilies suited to forcing and to mass commercial cultivation. The plant is an excellent garden plant, highly resistant to disease and shows tolerance of virus; the bulbs may be precooled and forced for cut flower production and the clone is vigorous, a good grower and a good propagator.
14214005
Incorporating a Metropolis method in a distribution estimation using Markov random field algorithm
Markov random field (MRF) modelling techniques have been recently proposed as a novel approach to probabilistic modelling for estimation of distribution algorithms (EDAs) (S. K. Shakya et al., 2004). An EDA using this technique was called distribution estimation using Markov random fields (DEUM). DEUM was later extended to DEUM/sub d/ (S. Shakya et al., 2005). DEUM and DEUM/sub d/ use a univariate model of probability distribution, and have been shown to perform better than other univariate EDAs for a range of optimization problems. This paper extends DEUM/sub d/ to incorporate a simple Metropolis method and empirically shows that for linear univariate problems the proposed univariate MRF models are very effective. In particular, the proposed DEUM/sub d/ algorithm can find the solution in O(n) fitness evaluations. Furthermore, we suggest that the Metropolis method can also be used to extend the DEUM approach to multivariate problems.
4495280
Mapping Nominal Values to Numbers for Effective Visualization
Data sets with a large numbers of nominal variables, including some with large number of distinct values, are becoming increasingly common and need to be explored. Unfortunately, most existing visual exploration tools are designed to handle numeric variables only. When importing data sets with nominal values into such visualization tools, most solutions to date are rather simplistic. Often, techniques that map nominal values to numbers do not assign order or spacing among the values in a manner that conveys semantic relationships. Moreover, displays designed for nominal variables usually cannot handle high cardinality variables well. This paper addresses the problem of how to display nominal variables in general-purpose visual exploration tools designed for numeric variables. Specifically, we investigate (1) how to assign order and spacing among the nominal values, and (2) how to reduce the number of distinct values to display. We propose a new technique, called the Distance-Quantification-Classing (DQC) approach, to preprocess nominal variables before being imported into a visual exploration tool. In the Distance Step, we identify a set of independent dimensions that can be used to calculate the distance between nominal values. In the Quantification Step, we use the independent dimensions and the distance information to assign order and spacing among the nominal values. In the Classing Step, we use results from the previous steps to determine which values within the domain of a variable are similar to each other and thus can be grouped together. Each step in the DQC approach can be accomplished by a variety of techniques. We extended the XmdvTool package to incorporate this approach. We evaluated our approach on several data sets using a variety of measures.
15121856
Agent-based and analytical modeling to evaluate the effectiveness of greenbelts
We present several models of residential development at the rural–urban fringe to evaluate the effectiveness of a greenbelt located beside a developed area, for delaying development outside the greenbelt. First, we develop a mathematical model, under two assumptions about the distributions of service centers, that represents the trade-off between greenbelt placement and width, their effects on the rate of development beyond the greenbelt, and how these interact with spatial patterns of aesthetic quality and the locations of services. Next, we present three agent-based models (ABMs) that include agents with the potential for heterogeneous preferences and a landscape with the potential for heterogeneous attributes. Results from experiments run with a one-dimensional ABM agree with the starkest of the results from the mathematical model, strengthening the support for both models. Further, we present two different two-dimensional ABMs and conduct a series of experiments to supplement our mathematical analysis. These include examining the effects of heterogeneous agent preferences, multiple landscape patterns, incomplete or imperfect information available to agents, and a positive aesthetic quality impact of the greenbelt on neighboring locations. These results suggest how width and location of the greenbelt could help determine the effectiveness of greenbelts for slowing sprawl, but that these relationships are sensitive to the patterns of landscape aesthetic quality and assumptions about service center locations. # 2004 Elsevier Ltd. All rights reserved.
1464370
Integer programming approaches to haplotype inference by pure parsimony
In 2003, Gusfield introduced the haplotype inference by pure parsimony (HIPP) problem and presented an integer program (IP) that quickly solved many simulated instances of the problem. Although it solved well on small instances, Gusfield's IP can be of exponential size in the worst case. Several authors have presented polynomial-sized IPs for the problem. In this paper, we further the work on IP approaches to HIPP. We extend the existing polynomial-sized IPs by introducing several classes of valid cuts for the IP. We also present a new polynomial-sized IP formulation that is a hybrid between two existing IP formulations and inherits many of the strengths of both. Many problems that are too complex for the exponential-sized formulations can still be solved in our new formulation in a reasonable amount of time. We provide a detailed empirical comparison of these IP formulations on both simulated and real genotype sequences. Our formulation can also be extended in a variety of ways to allow errors in the input or model the structure of the population under consideration