Methodological issues in the validation of implicit measures: Comment on De Houwer, Teige-Mocigemba, Spruyt, and Moors (2009).

J. De Houwer, S. Teige-Mocigemba, A. Spruyt, and A. Moors’s (see record 2009-05290-001) normative analysis of implicit measures provides an excellent clarification of several conceptual ambiguities surrounding the validation and use of implicit measures. The current comment discusses an important, yet unacknowledged, implication of J. De Houwer et al.’s analysis, namely, that investigations addressing the proposed implicitness criterion (i.e., does the relevant psychological attribute influence measurement outcomes in an automatic fashion?) will be susceptible to fundamental misinterpretations if they are conducted independently of the proposed what criterion (i.e., is the measurement outcome causally produced by the psychological attribute the measurement procedure was designed to assess?). As a solution, it is proposed that experimental validation studies should be combined with a correlational approach in order to determine whether a given manipulation influenced measurement scores via variations in the relevant psychological attribute or via secondary sources of systematic variance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Goal-directed responding is sensitive to lesions to the prelimbic cortex or basolateral nucleus of the amygdala but not to their disconnection.

The current view of instrumental conditioning indicates that performance in the early stage of training is maintained by a representation of the outcome, as indexed by its sensitivity to changes in the value of the reward. In the present study, the authors tested the effects of a disconnection of the prelimbic cortex (PL) and the basolateral nucleus of the amygdale (BLA), using an asymmetric lesion procedure, to determine whether these structures interact sequentially as part of a corticolimbic system. In marked contrast to the effects of bilateral lesions of the PL or the BLA, which both altered rats' sensitivity to outcome devaluation, the disconnection of these 2 brain areas was without an effect on outcome devaluation. These results demonstrate that the PL and the BLA mediate different aspects of outcome representation in goal-directed responding. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Using bottom surface reflectance to map coastal marine areas: a new application method for Lyzenga's model

Remote sensing is widely used in coastal management. Lyzenga's model has been traditionally used to explain the relationship between bottom surface reflectance and the radiance level measured by satellite. Due to its central assumption, this model lacks accuracy compared with the other radiative transfer models. Nonetheless, it enables, with a single and simple equation, representation of the multiple optical processes taking place in coastal areas. Mapping processes associated with this model may include radiometric correction, a technique previously pointed out as a major driver of mapping accuracy. Radiometric correction is generally based on a depth-invariant index, efficient for clear waters (Jerlov water type I to II) but largely unsuitable when transparency decreases (Jerlov water type II to III). In order to overcome this problem, we developed a new index for radiometric correction, which combines bathymetry data with attenuation coefficients. The improved efficiency of our model with regard to the traditional depth invariant index was demonstrated through two case studies: Funakoshi Bay (Japan; Jerlov water type II) and the Gabes Gulf part located off Mahares (Tunisia; Jerlov water type II to III).     

A Stochastic Filtering Technique for Fluid Flow Velocity Fields Tracking

In this paper, we present a method for the temporal tracking of fluid flow velocity fields. The technique we propose is formalized within a sequential Bayesian filtering framework. The filtering model combines an Itô diffusion process coming from a stochastic formulation of the vorticity-velocity form of the Navier-Stokes equation and discrete measurements extracted from the image sequence. In order to handle a state space of reasonable dimension, the motion field is represented as a combination of adapted basis functions, derived from a discretization of the vorticity map of the fluid flow velocity field. The resulting nonlinear filtering problem is solved with the particle filter algorithm in continuous time. An adaptive dimensional reduction method is applied to the filtering technique, relying on dynamical systems theory. The efficiency of the tracking method is demonstrated on synthetic and real-world sequences.     

A simple footskate removal method for virtual reality applications

Footskate is a common problem encountered in interactive applications dealing with virtual character animations. It has proven difficult to fix without the use of complex numerical methods, which require expert skills for their implementations, along with a fair amount of user interaction to correct a motion. On the other hand, deformable bodies are being increasingly used in virtual reality (VR) applications, allowing users to customize their avatar as they wish. This introduces the need of adapting motions without any help from a designer, as a random user seldom has the skills required to drive the existing algorithms towards the right solution. In this paper, we present a simple method to remove footskate artifacts in VR applications. Unlike previous algorithms, our approach does not rely on the skeletal animation to perform the correction but rather on the skin. This ensures that the final foot planting really matches the virtual character’s motion. The changes are applied to the root joint of the skeleton only so that the resulting animation is as close as possible to the original one. Eventually, thanks to the simplicity of its formulation, it can be quickly and easily added to existing frameworks.     

Weibull Parameters and the Tensile Strength of Porous Phosphate Glass-Ceramics

The strengths of porous phosphate glass-ceramic specimens, with relative densities ranging between 0.25 and 0.50, were measured by four-point bending at room temperature. An analysis of the data, using Weibull statistics, indicated that such a treatment, usually performed on dense ceramics, can also be used on porous materials. In the sets studied, the nature of critical flaws was determined, which led to the proposal of a mechanism of fracture initiation in such porous materials.     

Thermal behavior of an electrical motor through a reduced model

The aim of this study is to obtain quickly thermal information on some sensitive components of an electrical motor in a short lapse of time. The thermal behavior of this complex system is modeled and validated. The corresponding detailed model leads to the resolution of a linear system of differential equations of high order, but is not easy to handle for control purposes, due to long CPU time. In order to compute faster, two model reduction techniques are used: the Eitelberg method and the reduction by modal identification. The reduced models effectively give good temperature accuracy on the critical points of the motor with very fast computation time     

SPOT5-HRS digital elevation models and the monitoring of glacier elevation changes in North-West Canada and South-East Alaska

Monitoring the response of land ice to climate change requires accurate and repeatable topographic surveys. The SPOT5-HRS (High Resolution Stereoscopic) instrument covers up to 120 km by 600 km in a single pass and has the potential to accurately map the poorly known topography of most glaciers and ice caps. The acquisition of a large HRS archive over ice-covered regions is planned by the French Space Agency (CNES) and Spotimage, France during the 2007–2008 International Polar Year (IPY). Here, we report on the accuracy and value of HRS digital elevation model (DEM) over ice and snow surfaces.

A DEM is generated by combining tools available from CNES with the PCI Orthoengine^SE software, using HRS images acquired in May 2004 over South-East Alaska (USA) and northern British Columbia (Canada). The DEM is evaluated through comparison with shuttle radar topographic mission (SRTM) DEM and ICESAT data, on and around the glaciers. A horizontal shift of 50 m is found between the HRS and SRTM DEMs and is attributed to errors in the SRTM DEM. Over ice-free areas, HRS elevations are 7 m higher than those of SRTM, with a standard deviation of ± 25 m for the difference between the two DEMs. The 7-m difference is partly attributed to the differential penetration of the electromagnetic waves (visible for HRS; microwave for SRTM) in snow and vegetation.

We also report on the application of sequential DEMs (SRTM DEM in February 2000 and HRS DEM in May 2004) for the monitoring of glacier elevation changes. We map the topographic changes induced by a surge of one tributary of Ferris Glacier. Maximum surface lowering of 42 (± 10) m and rising of 77 (± 10) m are observed in the 4 years time interval. Thinning rates up to 10 (± 2.5) m/yr are observed at low altitudes and confirm the ongoing wastage of glaciers in South-East Alaska.     

Heat source identification and on-line temperature control by a Branch Eigenmodes Reduced Model

This paper presents the advantages of a Branch Eigenmodes Reduced Model used in a control process of a heating system.The experimental setup is a 3D heat conductive system in which a heat source is set. First, the reduced model is used to solve the non-linear Inverse Heat Conduction Problem: identification of the heat source strength variations from time-varying temperatures. Then, the reduced model is used to control hot points in the system. The objective of the method is to allow sequential temperature control by decreasing the computation time necessary for the simulation.