Representation and learning of visual information for pose recognition

Recovering position from sensor information is an important problem in mobile robotics, known as localisation. Localisation requires a map or some other description of the environment to provide the robot with a context to interpret sensor data. The mobile robot system under discussion is using an artificial neural representation of position. Building a geometrical map of the environment with a single camera and artificial neural networks is difficult. Instead it would be simpler to learn position as a function of the visual input. Usually when learning images, an intermediate representation is employed. An appropriate starting point for biologically plausible image representation is the complex cells of the visual cortex, which have invariance properties that appear useful for localisation. The effectiveness for localisation of two different complex cell models are evaluated. Finally the ability of a simple neural network with single shot learning to recognise these representations and localise a robot is examined.

Effects of temporal association on recognition memory

The influence of temporal association on the representation and recognition of objects was investigated. Observers were shown sequences of novel faces in which the identity of the face changed as the head rotated. As a result, observers showed a tendency to treat the views as if they were of the same person. Additional experiments revealed that this was only true if the training sequences depicted head rotations rather than jumbled views; in other words, the sequence had to be spatially as well as temporally smooth. Results suggest that we are continuously associating views of objects to support later recognition, and that we do so not only on the basis of the physical similarity, but also the correlated appearance in time of the objects.

Effects of temporal association on recognition memory

The influence of temporal association on the representation and recognition of objects was investigated. Observers were shown sequences of novel faces in which the identity of the face changed as the head rotated. As a result, observers showed a tendency to treat the views as if they were of the same person. Additional experiments revealed that this was only true if the training sequences depicted head rotations rather than jumbled views: in other words, the sequence had to be spatially as well as temporally smooth. Results suggest that we are continuously associating views of objects to support later recognition, and that we do so not only on the basis of the physical similarity, but also the correlated appearance in time of the objects.

Twisted sl(3, C)(k)((2)) current algebra: free field representation and screening currents

Motivated by application of twisted current algebra in description of the entropy of Ads(3) black hole, we investigate the simplest twisted current algebra sl(3, c)(k)((2)). Free field representation of the twisted algebra, and the corresponding twisted Sugawara energy-momentum tensor are obtained by using three (beta, gamma) pairs and two scalar fields. Primary fields and two screening currents of the first kind are presented. (C) 2001 Published by Elsevier Science B.V.

A revision of Benedenia Diesing, 1858 including a redescription of B-sciaenae (van Beneden, 1856) Odhner, 1905 and recognition of Menziesia Gibson, 1976 (Monogenea : Capsalidae)

Benedenia Diesing, 1858, a genus of capsalid (benedeniine) monogeneans, is redefined. The generic diagnosis is amended to include: the path of tendons in the haptor from extrinsic muscles in the body; presence and form of the marginal valve; a penis occupying a penis canal with weakly muscular wall; a weakly muscular accessory gland reservoir proximal to the penis and enclosed by a proximal extension of the wall of the penis canal; male and female genital apertures usually common, rarely separate; vagina with pore usually close to the common genital pore but may open in mid body between the germarium and the common genital pore, or anterior to the common genital pore. A conservative approach is adopted and the generic diagnosis is clarified and broadened to accommodate species that display some variation in reproductive anatomy, especially of the female system. We argue against potential alternative actions such as defining Benedenia strictly to contain species with separate male and female genital apertures and against recognition of a separate genus, Tareenia Hussey, 1986, for species with a vaginal pore anterior to the common genital pore. Under our conception, Benedenia comprises 21 species: B. sciaenae (van Beneden, 1856) Odhner, 1905 (type species); B. acanthopagri (Hussey, 1986) comb. nov.; B. anticavaginata Byrnes, 1986; B. bodiani Yamaguti, 1968; B. elongata (Yamaguti, 1968) Egorova, 1997; B. epinepheli (Yamaguti, 1937) Meserve, 1938; B. hawaiiensis Yamaguti, 1968; B. hendorffi(von Linstow, 1889) Odhner, 1905; B. hoshinai Ogawa, 1984; B. innobilitata Burhnheim Gomes and Varela, 1973: B. jaliscana Bravo-Hollis, 1952; B. lolo Yamaguti, 1968; B. lutjani Whittington and Kearn, 1993: B. monticellii (Parona and Perugia, 1895) Johnston, 1929; B. ovata (Goto, 1894) Johnston. 1929: B. pompatica Burhnheim, Gomes and Varela, 1973; B. rohdei Whittington, Kearn and Beverley-Burton, 1994; B. scari Yamaguti, 1968; B. sekii (Yamaguti, 1937) Meserve, 1938; B, seriolae (Yamaguti, 1934) Meserve, 1938; and B. synagris Yamaguti, 1953. The type species, B. sciaenae, is redescribed based on new material from Australia. No types for this taxon were designated and we have assigned a series of voucher specimens. Tareenia acanthopagri Hussey, 1986 becomes B. acanthopagri (Hussey, 1986) comb. nov. and T. anticavaginata (Byrnes, 1986) Egorova, 1997 and T. lutjani (Whittington and Kearn, 1993) Egorova, 1997 are returned to Benedenia as B. anticavaginata and B. lutjani Benedenia akaisaki Iwata, 1990 is considered a synonym of B. ovata and B. kintoki Iwata, 1990 is considered a synonym of B. elongata. Two species, B, madai Ishii and Sawada, 1938 and B. pagrosomi Ishii and Sawada, 1938, are considered species inquirendae. Based on the redefinition of Benedenia, the diagnosis for the Benedeniinae is amended. Tareenia is synonymized with Benedenia but Menziesia Gibson, 1976 is recognized and its generic diagnosis amended to include: anterior attachment organs tending to form a 'hooded' appearance; prominent anterior gland cells between the pharynx and the anterior margin of the body: long penis, tapering proximally, occupying a penis canal with weakly muscular wall: penis canal and penis describe a sigmoid; accessory gland reservoir dorsal and alongside, or posterior and lateral to, proximal end of the penis and enclosed by a proximal extension of the wall of the penis canal. Under this conception. Menziesia comprises: M. noblei (Menzies. 1946) Gibson, 1976 (type species); M. malaboni (Velasquez. 1982) comb. nov.: M. merinthe (Yamaguti, 1968) Gibson. 1976: M. ovalis (Yamaguti, 1968) Gibson, 1976: and M. sebastodis (Yamaguti, 1934) comb, nov. A key to valid species of Benedenia and Menziesia is provided and a list is presented of published records of undescribed or unattributed species of Benedenia. Some protocols are suggested for preparation of benedeniine material to enhance future taxonomic studies and comparisons. The host-specificity and geographic distribution of species in these revised genera are discussed. The composition of the Capsalidae is discussed and some difficulties in defining and distinguishing between its different subfamilies are considered.

A comparison of low-storage strategies for spectral analysis in dissipative systems: filter diagonalisation in the Lanczos representation and harmonic inversion of the Chebychev-order-domain autocorrelation function

We compare the performance of two different low-storage filter diagonalisation (LSFD) strategies in the calculation of complex resonance energies of the HO2, radical. The first is carried out within a complex-symmetric Lanczos subspace representation [H. Zhang, S.C. Smith, Phys. Chem. Chem. Phys. 3 (2001) 2281]. The second involves harmonic inversion of a real autocorrelation function obtained via a damped Chebychev recursion [V.A. Mandelshtam, H.S. Taylor, J. Chem. Phys. 107 (1997) 6756]. We find that while the Chebychev approach has the advantage of utilizing real algebra in the time-consuming process of generating the vector recursion, the Lanczos, method (using complex vectors) requires fewer iterations, especially for low-energy part of the spectrum. The overall efficiency in calculating resonances for these two methods is comparable for this challenging system. (C) 2001 Elsevier Science B.V. All rights reserved.