Screen design with dynamic symmetry: A discovery

Hambidge's study of Greek art convinced him that the secret of the beauty of Greek design was in the conscious utilization of dynamic symmetry - the law of natural design based upon the symmetry of growth in man and in plants. While our study of dynamic symmetry that underlies 150 real screens shows an unmistakable use of plan schemes of the proportioning system in 61% of them, few adhere absolutely to it. Nevertheless, the evidence leads to the conclusion that layout was probably approximated by designers of great native ability whose sense of form is highly developed. (C) 2004 Elsevier Ltd. All rights reserved

Multipoint-to-multipoint secure-messaging with threshold-regulated authorisation and sabotage detection

This paper presents multi-user protocol-extensions for Schnoff/Nyberg-Ruepple (NR) signatures and Zheng signcryption, both of which are elliptic curve (EC)/discrete logarithmic (DL) formulations. Our extension methodology is based on k-of-n threshold cryptography-with Shamir polynomial parameterisation and Feldman-Pedersen verification-resulting in multi-sender Schnorr-NR (SNR) and multi-sender/receiver Zheng-NR (ZNR) protocols, all of which are interoperable with their single-user base formulations. The ZNR protocol-extensions are compared with the earlier Takaragi et al multi-user sign-encryption, which is extended from a base-protocol with two random key-pairs following the usual specification of one each of signing and encryption. Both single and double-pair formulations are analysed from the viewpoint of EC equivalence (EQ) establishment, which is required for rigorous multi-sender functionality. We outline a rectification to the original Takaragi et al formulation; thereby enabling parameter-share verification, but at significantly increased overheads. This enables comprehensive equivalent-functionality comparisons with the various multi-user ZNR protocol-extensions. The single-pair ZNR approach is shown to be significantly more efficient, in some cases demonstrating a two/three-fold advantage

An expert screen design and evaluation assistant that uses knowledge-based backtracking

Current user interface builders provide only low-level assistance, because they have knowledge of neither the application, nor the principles by which interface elements are combined effectively. We describe a design tool that unites the knowledge components essential for effective dialog box layout. The knowledge base model consists of (1) style knowledge, which provides design-time constraints on interface specifications; (2) style application system, which handles the actual layout of dialog boxes based on the style knowledge base; (3) design knowledge, which provides quantitative metrics to analyse the spatial properties of the dialog box layout; and (4) design evaluation system, which uses evaluation metrics to compare and evaluate alternative designs. As our empirical study shows, the redesigns using the design tool had significant effect on the preference data. (C) 2002 Elsevier Science B.V. All rights reserved

Computation of cryptographic keys from face biometrics

We outline cryptographic key-computation from biometric data based on error-tolerant transformation of continuous-valued face eigenprojections to zero-error bitstrings suitable for cryptographic applicability. Biohashing is based on iterated inner-products between pseudorandom and user-specific eigenprojections, each of which extracts a single-bit from the face data. This discretisation is highly tolerant of data capture offsets, with same-user face data resulting in highly correlated bitstrings. The resultant user identification in terms of a small bitstring-set is then securely reduced to a single cryptographic key via Shamir secret-sharing. Generation of the pseudorandom eigenprojection sequence can be securely parameterised via incorporation of physical tokens. Tokenised bio-hashing is rigorously protective of the face data, with security comparable to cryptographic hashing of token and knowledge key-factors. Our methodology has several major advantages over conventional biometric analysis ie elimination of false accepts (FA) without unacceptable compromise in terms of more probable false rejects (FR), straightforward key-management, and cryptographically rigorous commitment of biometric data in conjunction with verification thereof

Why and how should design patterns be formalized?

Textual descriptions of design patterns are ambiguous and may lead to conflicting interpretations. Since patterns are meant for communication and education, a correct and complete understanding is a prerequisite to their successful usage. Formal specification of design patterns is meant to complement existing textual descriptions. Formal specification allows a rigorous reasoning of design patterns and facilitates tool support for their usage

Flexibly-configurable and computation-efficient digital cash with polynomial-thresholded coinage

This paper describes an extension of the Brands protocol to incorporate flexibly-divisble k-term Coins via application of Shamir polynomial parameterisation and Feldman-Pedersen zero knowledge (ZK) verification. User anonymity is preserved for up to k sub-Coin Payments per k-term Coin, but revoked for over-Payments with (k+1) or more sub-Coins. Poly-cash construction using only discrete logarithm (DL) or elliptic curve (EC) operations enables efficient implementation in terms of the latter; which constitutes an advantage over previous divisble Coin formulations based on quadratic residue (QR) binary-trees, integer factorisation (IF) cryptography or hybrid DL/IF. Comparative analysis of Poly-cash and previous protocols illustrates the advantages of the former for operationally realistic Coin sub-denominations. The advantage of Poly-cash in terms computational overhead is particularly significant, and facilitates implementation on lightweight User Purses and Merchant Payment-terminals. Configurable k-divisibility is also an important consideration for real-world applicability with decimal currency denominations, which is not well addressed by the binarised values of QR-tree divisible Coins

Iris authentication using privatized advanced correlation filter

his paper proposes a private biometrics formulation which is based on the concealment of random kernel and the iris images to synthesize a minimum average correlation energy (MACE) filter for iris authentication. Specifically, we multiply training images with the user-specific random kernel in frequency domain before biometric filter is created. The objective of the proposed method is to provide private biometrics realization in iris authentication in which biometric template can be reissued once it was compromised. Meanwhile, the proposed method is able to decrease the computational load, due to the filter size reduction. It also improves the authentication rate significantly compare to the advance correlation based approach [5][6] and comparable to the Daugmant's Iris Code [1]

Sorted locally confined non-negative matrix factorization in face verification

In this paper, we propose a face recognition technique based on modification of Non-Negative Matrix Factorization (NMF) technique, which known as Sorted Locally Confined NMF (SLC-NMF). SLC-NMF used NMF to find non negative basis images, subset of them were selected according to a discriminant factor and then processed through a series of image processing operation; to yield a set of ideal locally confined salient feature basis images. SLC-NMF illustrates perfectly local salient feature region which effectively realize "recognition by parts" paradigm for face recognition. The best performance is attained by SLC-NMF compare to the PCA, NMF and local NMF, in FERET Face Database

Eigenspace-based face hashing

We present a novel approach to generating cryptographic keys from biometrics. In our approach, the PCA coefficients of a face image are discretised using a bit-extraction method to n bits. We compare performance results obtained with and without the discretisation procedure applied to several PCA-based methods (including PCA, PCA with weighing coefficients, PCA on Wavelet Subband, and LDA) on a combined face image database. Results show that the discretisation step consistently increases the performance