An adaptive learning approach for 3-D surface reconstruction from point clouds.

In this paper, we propose a multiresolution approach for surface reconstruction from clouds of unorganized points representing an object surface in 3-D space. The proposed method uses a set of mesh operators and simple rules for selective mesh refinement, with a strategy based on Kohonen's self-organizing map (SOM). Basically, a self-adaptive scheme is used for iteratively moving vertices of an initial simple mesh in the direction of the set of points, ideally the object boundary. Successive refinement and motion of vertices are applied leading to a more detailed surface, in a multiresolution, iterative scheme. Reconstruction was experimented on with several point sets, including different shapes and sizes. Results show generated meshes very close to object final shapes. We include measures of performance and discuss robustness.     

Biliary dyskinesia: natural history and surgical results

Patients with biliary dyskinesia have symptoms consistent with biliary colic and an abnormal gallbladder ejection fraction (GEF) in the absence of cholelithiasis. Cholecystokinin hepatobiliary scan quantifies gallbladder function and may assist in selecting patients with acalculous biliary pain who would benefit from cholecystectomy. Seventy-eight patients with an abnormal GEF (< 35%) on cholecystokinin hepatobiliary scan without cholelithiasis were studied retrospectively. Patients were divided into groups based on diagnosis and treatment. In Group I, the patients who underwent cholecystectomy, 80 per cent (35 of 44) had complete symptomatic resolution whereas the remaining 20 per cent (9 of 44) had symptomatic improvement. Pathology reports demonstrated chronic cholecystitis in 95 per cent of specimens. Group II were patients with symptoms attributable to biliary dyskinesia, but did not undergo cholecystectomy. Persistence of symptoms was noted in 75 per cent (18 of 24) of patients whereas 25 per cent (6 of 24) had symptomatic resolution without any treatment. Group III consisted of patients with an abnormal ejection fraction who had improvement of symptoms after treatment for an alternative diagnosis (n = 10). These findings suggest that an abnormal ejection fraction does not always indicate gallbladder disease. Alternative diagnoses must be investigated and treated. Patients with persistent biliary type symptoms in combination with an abnormal GEF in the absence of other attributable causes can expect a favorable response to cholecystectomy.     

Local controllability of nonlinear systems

The local controllability of control systems with an arbitrary number of controls is considered, first on an open set and then at a given point; necessary conditions are derived concerning the Lie algebra T′ generated by the input vector fields, and applied to gradient systems.The main results are a geometric sufficient condition for local controllability at a point, and an equivalent condition based on the computation of Lie brackets, assuming T′ to be (n − 1)-dimensional.     

Recurrent neural network approach for cyclic job shop scheduling problem

While cyclic scheduling is involved in numerous real-world applications, solving the derived problem is still of exponential complexity. This paper focuses specifically on modelling the manufacturing application as a cyclic job shop problem and we have developed an efficient neural network approach to minimise the cycle time of a schedule. Our approach introduces an interesting model for a manufacturing production, and it is also very efficient, adaptive and flexible enough to work with other techniques. Experimental results validated the approach and confirmed our hypotheses about the system model and the efficiency of neural networks for such a class of problems.     

Proper Orthogonal Decomposition and Statistical Analysis of 2D Confined Impinging Jets Chaotic Flow

Proper orthogonal decomposition (POD) is shown to be a statistical operation that identifies the main characteristics of chaotic flows and separates them into a few modes. The dynamic chaotic flow is obtained from two‐dimensional (2D) computational fluid dynamics simulations, for different Reynolds numbers, of a confined impinging jets mixer. POD enables reconstruction of the dynamic flow from a few modes that are related to coherent flow structures. The POD flow reconstruction enables a large compression of the flow data set. The decomposition of the flow field into orthogonal modes related to coherent structures provides direct insight into the mixing dynamics and scales which are not accessible from flow dynamics statistic quantities, which were introduced in the context of turbulence and are here applied to chaotic flow.     

Pseudo affine Wigner distributions: definition and kernelformulation

We introduce a new set of tools for time-varying spectral analysis: the pseudo affine Wigner distributions. Based on the affine Wigner distributions of J. and P. Bertrand (1992), these new time-scale distributions support efficient online operation at the same computational cost as the continuous wavelet transform. Moreover, they take advantage of the proportional bandwidth smoothing inherent in the sliding structure of their implementation to suppress cumbersome interference components. To formalize their place within the echelon of the affine class of time-scale distributions (TSDs), we introduce and study an alternative set of generators for this class     

Contribution of phosphoinositides and phosphatidylcholines to the production of phosphatidic acid upon concanavalin A stimulation of rat thymocytes

Stimulation of rat thymocytes by concanavalin A (Con A) results in a very early increase of the cellular level of phosphatidic acid (PA), while that of diacylglycerol (DAG) was not affected. As the biological activity of PA is very likely to be determined by its molecular species composition, the present study aims to investigate the pathways leading to the production of PA in Con A-stimulated rat thymocytes. Prelabeling the cells with [3H]arachidonic acid, [3H]myristic acid, [3H]choline, or [14C]lysophosphatidylcholine allowed us to determine that PA is formed by both phosphoinositide (PIs) and phosphatidylcholine (PC) hydrolysis. We then investigated whether PA derived from PC was formed by phospholipase C (PLC) or phospholipase D (PLD) hydrolysis. In the presence of 1-butanol, the production of phosphatidylbutanol was only observed in tetradecanoyl phorbol acetate (TPA)-stimulated cells. The use of a specific PC phospholipase C inhibitor resulted in a decrease of Con A-stimulated PA production in cells labeled with [3H]myristate. When cells were labeled with [3H]choline, only TPA stimulation induced a release of labeled choline. All together, these experiments suggest that PA is originated from two phospholipid sources, predominantly PI via PLC hydrolysis and to a lesser extent PC, by PLC hydrolysis also. Molecular species analyses by reverse phase HPLC are in agreement with this hypothesis, as diacyl-GP molecular species composition is similar to that of diacyl-GPC and DAG in resting cells, but resembles that of diacyl-GPI in Con A-treated cells. Thus, in stimulated cells, the amount of 18:0/20:4 species doubled while those of saturated and monounsaturated species decreased.     

The value of prognostic factors in the management of stage I nonseminomatous germ cell testicular tumors (NSGCTT)

A patient with florid hypertrophic pulmonary osteoarthropathy (HPOA) associated with metastatic nasopharyngeal carcinoma is presented. Despite the presence of metastatic disease in the thorax and in bone, the patient's main symptom was severe pain from the HPOA, which was temporarily relieved by chemotherapy. Her disease subsequently progressed during chemotherapy and the pain became resistant to conventional treatment, including high dose morphine, non-steriodal anti-inflammatory agents and steriods. It was only with local radiation to the involved joints that the pain could be controlled. Our patient demonstrates that local radiotherapy is an option for the palliation of extreme HPOA.