How to use parametric curved folding design methods- a case study and comparison

Designs based on developable surfaces can be convenient for many reasons, however designing developable patterns that make use of curved creases is a challenge. Many studies propose new methods to tackle the problem but sometimes these methods do not generate a parametric model which is easily modifiable by changing the input parameters. Furthermore, the known methods are applicable only to certain families of curved folded models, because there is no generalized method for curved folding yet. Thus, sometimes, it is hard for designers to decide which method is more suitable for their needs. This paper shows how to use different well-known and newer approaches to produce parametric curved folded designs. The potentialities and criticalities of three approaches are compared by applying them to the same case study, namely the “curved folded tripod”. The aim, thus, is to make the design of curved folded geometries more accessible to designers without a background in origami theory

Linear pose estimate from corresponding conics

We propose here a new method to recover the orientation and position of a plane by matching at least three projections of a conic lying on the plane itself. The procedure is based on rearranging the conic projection equations such that the non linear terms are eliminated. It works with any kind of conic and does not require that the shape of the conic is known a-priori. The method was extensively tested using ellipses, but it can also be used for hyperbolas and parabolas. It was further applied to pairs of lines, which can be viewed as a degenerate case of hyperbola, without requiring the correspondence problem to be solved first. Critical configurations and numerical stability have been analyzed through simulations. The accuracy of the proposed algorithm was compared to that of traditional algorithms and of a trinocular vision system using a set of landmarks

Universal Calcium fluctuations in Hydra morphogenesis

Morphogenesis in development involves significant morphological transitions toward the emerging body plan of a mature animal. Understanding how the collective physical processes drive robust morphological patterning requires the characterization of the underlying relevant fields. Calcium (Ca2+) is known to be such a field. Here we show that the Ca2+ spatial fluctuations, in whole-body Hydra regeneration, exhibit universal properties captured by a field-theoretic model describing fluctuations in a tilted double-well potential. We utilize an external electric field and Heptanol, a drug blocking gap junctions, as two separate controls affecting the Ca2+ activity and pausing the regeneration process in a reversible way. Subjecting the Hydra tissue to an electric field increases the calcium activity and its spatial correlations, while applying Heptanol inhibits the activity and weakens the spatial correlations. Statistical characteristics of the Ca2+ spatial fluctuations, i.e., the coefficient of variation and the skewness, exhibit universal shape distributions across tissue samples and conditions, demonstrating the existence of global constraints over this field. Our analysis shows that the Hydra's tissue resides near the onset of bistability. The controls modulate the dynamics near that onset in a way that preserves the tissue's ability to regenerate, which is reflected by the aforementioned universality

Data mining techniques on satellite images for discovery of risk areas

The high rates of cholera epidemic mortality in less developed countries is a challenge for health fa- cilities to which it is necessary to equip itself with the epidemiological surveillance. To strengthen the capacity of epidemiological surveillance, this paper focuses on remote sensing satellite data processing using data mining methods to discover risk areas of the epidemic disease by connecting the environ- ment, climate and health. These satellite data are combined with field data collected during the same set of periods in order to explain and deduct the causes of the epidemic evolution from one period to another in relation to the environment. The existing technical (algorithms) for processing satellite im- ages are mature and efficient, so the challenge today is to provide the most suitable means allowing the best interpretation of obtained results. For that, we focus on supervised classification algorithm to process a set of satellite images from the same area but on different periods. A novel research method- ology (describing pre-treatment, data mining, and post-treatment) is proposed to ensure suitable means for transforming data, generating information and extracting knowledge. This methodology consists of six phases: (1.A) Acquisition of information from the field about epidemic, (1.B) Satellite data acquisition, (2) Selection and transformation of data (Data derived from images), (3) Remote sensing measurements, (4) Discretization of data, (5) Data treatment, and (6) Interpretation of results. The main contributions of the paper are: to establish the nature of links between the environment and the epidemic, and to highlight those risky environments when the public awareness of the problem and the prevention policies are absolutely necessary for mitigation of the propagation and emergence of the epidemic. This will allow national governments, local authorities and the public health officials to effective management according to risk areas. The case study concerns the knowledge discovery in databases related to risk areas of the cholera epidemic in Mopti region, Mali (West Africa). The results generate from data mining association rules indicate that the level of the Niger River in the wintering periods and some societal factors have an impact on the variation of cholera epidemic rate in Mopti town. More the river level is high, at 66% the rate of contamination is high

Radiomics and Artificial Intelligence for Outcome Prediction in Multiple Myeloma Patients

The significant clinical heterogeneity of Multiple Myeloma (MM) patients implies that a set of consolidated biomarkers is currently missing. Radiomics is an advanced, quantitative feature-based methodology for image analysis. We assess the feasibility of an AI-based approach for the automatic stratification of MM patients from CT data, and for the automatic identification of radiological biomarkers with a possible prognostic value. A retrospective analysis of n = 33 transplanted MM with focal lesion were performed via an open-source toolbox that extracted 109 radiomics features. The redundancy reduction was realized via correlation and principal component analysis. The highest sensitivity and critical success index (CSI) were obtained representing each patient, with 17 focal features selected via correlation with the 24 features describing the overall skeletal asset. The Mann\u2013 Whitney U-test showed that three among the 17 imaging descriptors passed the null hypothesis. This computational approach to the interpretation of radiomics features shows the potential for the stratification of relapsed and non-relapsed MM patients, and could represent a prognostic image-based procedure for determining the disease follow-up and therapy

The Morphology of the Rat Vibrissal Array: A Model for Quantifying Spatiotemporal Patterns of Whisker-Object Contact

In all sensory modalities, the data acquired by the nervous system is shaped by the biomechanics, material properties, and the morphology of the peripheral sensory organs. The rat vibrissal (whisker) system is one of the premier models in neuroscience to study the relationship between physical embodiment of the sensor array and the neural circuits underlying perception. To date, however, the three-dimensional morphology of the vibrissal array has not been characterized. Quantifying array morphology is important because it directly constrains the mechanosensory inputs that will be generated during behavior. These inputs in turn shape all subsequent neural processing in the vibrissal-trigeminal system, from the trigeminal ganglion to primary somatosensory (“barrel”) cortex. Here we develop a set of equations for the morphology of the vibrissal array that accurately describes the location of every point on every whisker to within ±5% of the whisker length. Given only a whisker's identity (row and column location within the array), the equations establish the whisker's two-dimensional (2D) shape as well as three-dimensional (3D) position and orientation. The equations were developed via parameterization of 2D and 3D scans of six rat vibrissal arrays, and the parameters were specifically chosen to be consistent with those commonly measured in behavioral studies. The final morphological model was used to simulate the contact patterns that would be generated as a rat uses its whiskers to tactually explore objects with varying curvatures. The simulations demonstrate that altering the morphology of the array changes the relationship between the sensory signals acquired and the curvature of the object. The morphology of the vibrissal array thus directly constrains the nature of the neural computations that can be associated with extraction of a particular object feature. These results illustrate the key role that the physical embodiment of the sensor array plays in the sensing process

Range Finding with a Plenoptic Camera

The plenoptic camera enables simultaneous collection of imagery and depth information by sampling the 4D light field. The light field is distinguished from data sets collected by stereoscopic systems because it contains images obtained by an N by N grid of apertures, rather than just the two apertures of the stereoscopic system. By adjusting parameters of the camera construction, it is possible to alter the number of these `subaperture images,\u27 often at the cost of spatial resolution within each. This research examines a variety of methods of estimating depth by determining correspondences between subaperture images. A major finding is that the additional \u27apertures\u27 provided by the plenoptic camera do not greatly improve the accuracy of depth estimation. Thus, the best overall performance will be achieved by a design which maximizes spatial resolution at the cost of angular samples. For this reason, it is not surprising that the performance of the plenoptic camera should be comparable to that of a stereoscopic system of similar scale and specifications. As with stereoscopic systems, the plenoptic camera has its most immediate, realistic applications in the domains of robotic navigation and 3D video collection