Weiss-Weinstein bound for MIMO radar with colocated linear arrays for SNR threshold prediction

Several works have suggested that a multi-input multi-output (MIMO) radar system offers improvement in terms of performance in comparison with classical phased-array radar. However, under the widely spread assumption of a uniform a priori distribution for one parameter of interest, there is no result concerning lower bounds on the mean-square error in the case of a Gaussian observation model with parameterized mean. This Fast Communication fills this lack by using the Weiss-Weinstein bound (WWB) which can be calculated under this difficult scenario. As we will show, the proposed bound for MIMO Radar with colocated linear arrays has no closed-form expression. To solve this problem, we propose a closed-form approximation that, as we will show by simulations, is close to the actual bound. This approximated bound is then analyzed for a design purpose in terms of array geometry. Simulations confirm the good ability of the proposed bound to predict the mean square error (MSE) of the maximum a posteriori (MAP) in all ranges of SNR. Particularly, the tightness of the bound to predict the SNR threshold effect is shown.     

Classification of periodic activities using the Wasserstein distance

In this paper, we introduce a novel nonparametric classification technique based on the use of the Wasserstein distance. The proposed scheme is applied in a biomedical context for the analysis of recorded accelerometer data: the aim is to retrieve three types of periodic activities (walking, biking, and running) from a time-frequency representation of the data. The main interest of the use of the Wasserstein distance lies in the fact that it is less sensitive to the location of the frequency peaks than to the global structure of the frequency pattern, allowing us to detect activities almost independently of their speed or incline. Our system is tested on a 24-subject corpus: results show that the use of Wasserstein distance combined with some supervised learning techniques allows us to compare with some more complex classification systems.     

Closed-form inverse kinematics for interventional C-arm X-ray imaging with six degrees of freedom: modeling and application

For trauma and orthopedic surgery, maneuvering a mobile C-arm fluoroscope into a desired position to acquire an X-ray is a routine surgical task. The precision and ease of use of the C-arm becomes even more important for advanced interventional imaging techniques such as parallax-free X-ray image stitching. Today's standard mobile C-arms have been modeled with only five degrees of freedom (DOF), which definitely restricts their motions in 3-D Cartesian space. In this paper, we present a method to model both the mobile C-arm and patient's table as an integrated kinematic chain having six DOF without constraining table position. The closed-form solutions for the inverse kinematics problem are derived in order to obtain the required values for all C-arm joint and table movements to position the fluoroscope at a desired pose. The modeling method and the closed-form solutions can be applied to general isocentric or nonisocentric mobile C-arms. By achieving this we develop an efficient and intuitive inverse kinematics-based method for parallax-free panoramic X-ray imaging. In addition, we implement a 6-DOF C-arm system from a low-cost mobile fluoroscope to optimally acquire X-ray images based solely on the computation of the required movement for each joint by solving the inverse kinematics on a continuous basis. Through simulation experimentation, we demonstrate that the 6-DOF C-arm model has a larger working space than the 5-DOF model. C-arm repositioning experiments show the practicality and accuracy of our 6-DOF C-arm system. We also evaluate the novel parallax-free X-ray stitching method on phantom and dry bones. Using five trials, results show that parallax-free panoramas generated by our method are of high visual quality and within clinical tolerances for accurate evaluation of long bone geometry (i.e., image and metric measurement errors are less than 1% compared to ground-truth).     

The core‐periphery model with three regions and more*

We determine the properties of the core‐periphery model with three regions and compare our results with those of the standard 2‐region model. The conditions for the stability of dispersion and concentration are established. As in the 2‐region model, dispersion and concentration can be simultaneously stable. We show that the 3‐region (2‐region) model favours the concentration (dispersion) of economic activity. Furthermore, we provide some results for the n‐region model. We show that the stability of concentration of the 2‐region model implies that of any model with an even number of regions. Determinamos las propiedades de un modelo núcleo‐periferia de tres regiones y comparamos nuestros resultados con los del modelo estándar de dos regiones. Se establecen las condiciones para la estabilidad de la dispersión y la concentración. Al igual que en el modelo de dos regiones, la dispersión y la concentración pueden ser estables simultáneamente. Mostramos que el modelo de tres regiones (dos regiones) favorece la concentración (dispersión) de la actividad económica. Además, aportamos algunos resultados para un modelo n‐regional. Mostramos que la estabilidad de la concentración del modelo bi‐regional implica eso mismo de cualquier modelo con un número par de regiones.      

Varietal and geographic classification of French red wines in terms of elements,amino acids and aromatic alcohols

Thirty-four French red wines from three regions already studied for their anthocyanin and flavonoid constituents have been further analysed for elements, amino acids and aromatic alcohols. An interpretation of the differences between wines related to their different geographic and varietal origins has been made from the results of statistical analyses: F statistic, principal component analysis (PCA) and stepwise discriminant analysis (SDA). Wine samples produced near Bordeaux were found to be characterised by higher rubidium and lower lithium and calcium concentrations. Differences between wine samples made from the same grape variety or produced in the same region are mainly related to differences in potassium and ash contents. The PCA demonstrates that the concentration of most amino acids in wines is mainly a function of the technology used in wine production. Moreover, it shows that the concentration of proline, hydroxyproline and ethanolamine are generally lower in wines prepared from Carignan, Cinsault and Grenache grapes than in wines from Cabernet Franc, Cabernet Sauvignon or Merlot grapes. Finally, it shows clear differences between wines according to the latitude of the production centre. These differences correspond to increasing total nitrogen content from south to north, ie Narbonne and Bordeaux versus Angers. In discriminant analysis Bordeaux wines were characterised by high rubidium and low arginine concentrations, Angers wines by a lower arginine content and Narbonne wines by their abundance of magnesium and deficiency of ethanolamine.     

Relation between volumetric changes of unsaturated polyester resin and surface finish quality of fiberglass/unsaturated polyester composite panels

Resin dimensional changes, including cure shrinkage and thermal expansion, highly influence the surface finish quality of composite parts. Low profile additives (LPA) are commonly incorporated in unsaturated polyester (UP) resins to compensate for resin shrinkage and obtain a high quality surface finish. In this study, the dimensional change of an UP resin with different LPA contents was characterized. Both resin cure shrinkage and resin thermal expansion were measured. A simple methodology was then developed to estimate the surface finish quality of panels, manufactured by resin transfer molding (RTM), based on the prediction of part thickness variation during the process. Results show good agreement with the experimental investigations. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers     

Cure shrinkage characterization of an epoxy resin system by two in situ measurement methods

Dimensional accuracy of composites manufacturing is a major issue for part producers, especially when tight tolerances are required. One of the main causes of dimensional variations is the resin volumetric changes during the cure. In this article, volumetric cure shrinkage of a one part epoxy system was characterized using two different methods. First, a modified rheology method was used to measure the volumetric cure shrinkage after the gel point. Second, a gravimetric method measured the shrinkage over the entire cure. A linear relationship between the volumetric cure shrinkage and the degree‐of‐cure was deduced from the results and the resin cure kinetic models. Results show a good agreement between the two techniques. POLYM. COMPOS., 31:1603–1610, 2010. © 2009 Society of Plastics Engineers     

Simulation and evaluation of pilot-scale pulsed electric field (PEF) processing

Pulsed electric field (PEF) processing is a novel mild treatment for pumpable foods preservation at low or moderate temperatures. The electric field strength and the temperature distribution in the treatment chamber have been identified as the key processing parameters affecting the treatment efficacy and possibly the sensorial and nutritional quality of the food. A full 3D computational fluid dynamics (CFD) model of a pilot-scale PEF system with co-linear configuration of the electrodes was developed. The model couples the fluid dynamics and the electrical field and can be used to predict the liquid’s flow pattern, electric field distribution, temperature increase, and residence time in the treatment chamber. A total of 48 process conditions with different settings of applied voltage V, pulse length τ, pulse repetition rate (frequency) f and flow rate in combination with four different inlet temperatures were simulated for a model liquid food (NaCl solutions with two different electrical conductivities) and whole milk. The simulated PEF energy dissipated into the liquids was between 4 and 66 kJ/kg and process temperatures ranged from approximately 25 to 80 °C. The predicted temperature data agree well (R² > 0.99) with experimental measurements in five locations of the treatment chamber using fibre optic probes.     

Channel height dependent protein nucleation and crystal growth in microfluidic devices

We report on results of a study of protein crystallization in microfluidic devices with different channel heights. Multilayer soft lithography has been used for the fabrication of devices with integrated micro-valves and crystallization channels of height in the range from 15 μm to 180 μm. To demonstrate the channel height dependent nucleation and crystal growth, a standard batch crystallization solution composed of 60 mg/ml lysozyme, 100 mM acetate buffer pH 4.6 and 1.5 M NaCl was used with minimized sample quantity. Our results show that deep channels favorite the nucleation whereas shallow ones favorite the crystal growth. When the channel height is less than 50 μm the number of lysozyme crystals is dramatically reduced whereas their mean size is increased. Furthermore, our results also show the feasibility of decoupling nucleation and crystal growth in a stair-like channel which should facilitate the appearance of single crystals suitable for X-ray diffraction.