Can a workspace help to overcome the query formulation problem in image retrieval?

We have proposed a novel image retrieval system that incorporates a workspace where users can organise their search results. A task-oriented and user-centred experiment has been devised involving design professionals and several types of realistic search tasks. We study the workspace’s effect on two aspects: task conceptualisation and query formulation. A traditional relevance feedback system serves as baseline. The results of this study show that the workspace is more useful with respect to both of the above aspects. The proposed approach leads to a more effective and enjoyable search experience

Novel Sum-of-Sinusoids Simulation Models for Rayleigh and Rician Fading Channels

The statistical properties of Clarke\u27s fading model with a finite number of sinusoids are analyzed, and an improved reference model is proposed for the simulation of Rayleigh fading channels. A novel statistical simulation model for Rician fading channels is examined. The new Rician fading simulation model employs a zero-mean stochastic sinusoid as the specular (line-of-sight) component, in contrast to existing Rician fading simulators that utilize a non-zero deterministic specular component. The statistical properties of the proposed Rician fading simulation model are analyzed in detail. It is shown that the probability density function of the Rician fading phase is not only independent of time but also uniformly distributed over [-pi, pi). This property is different from that of existing Rician fading simulators. The statistical properties of the new simulators are confirmed by extensive simulation results, showing good agreement with theoretical analysis in all cases. An explicit formula for the level-crossing rate is derived for general Rician fading when the specular component has non-zero Doppler frequenc

Second-Order Statistical Properties of the WSS Jakes\u27 Fading Channel Simulator

An improved Jakes\u27 (1994) fading channel simulator was proposed by Pop and Beaulieu (see ibid., vol.49, p.699-708, Apr. 2001) to eliminate the stationarity problem occurring in Jakes\u27 original design. In this paper, second-order statistical properties of the improved Jakes\u27 simulator are analyzed. Consistent with Pop and Beaulieu\u27s caution about high-order statistics of the simulator, it is proved that some second-order statistics of both the quadrature components and the envelope do not match the desired ones even if the number of sinusoids approaches infinity. Therefore, care must be taken when the simulator is employed to evaluate algorithms and systems

Phenotypic Correlations Between Juvenile-Mature Wood Density and Growth in Black Spruce

Phenotypic correlations between juvenile-mature wood density and growth were examined based on increment core samples from two plantations, a provenance test and a commercial plantation, of black spruce [Picea mariana (Mill.) B.S.P.]. The ring density components are significantly correlated to their respective ring width components: earlywood and ring densities are negatively correlated to ring and earlywood widths, respectively, while ring and latewood densities are positively correlated to latewood width. These hold true in both juvenile and mature wood. However, the correlation between ring width and ring density decreases with increasing age. This suggests that the correlation between wood density and growth rate tends to lessen as the tree ages. For each character, the correlation between juvenile and mature wood is significant but moderate. Thus, juvenile wood characters are only indicative of mature wood ones. On the other hand, trees with 12 growth rings from the pith were good predictors of wood density and radial growth of the whole tree. Individual growth rings from the juvenile-mature wood transition zone can be used to predict to some extent the wood density of either mature wood or the whole tree