A Probabilistic Approach to Concurrent Mapping and Localization for Mobile Robots

This paper addresses the problem of building large-scale geometric maps of indoor environments with mobile robots. It poses the map building problem as a constrained, probabilistic maximum-likelihood estimation problem. It then devises a practical algorithm for generating the most likely map from data, along with the most likely path taken by the robot. Experimental results in cyclic environments of size up to 80 by 25 meter illustrate the appropriateness of the approach.     

Robert A. Harper (1915-2004).

Presents the obituary for Robert A. Harper (1915-2004). Dr. Harper is noted for his contributions to the field of psychotherapy, particularly to the areas of marriage, family, and sex therapy. In addition, his expertise, good nature, and no-nonsense style made him a popular figure amongst his peers, who elected him to leadership positions in numerous professional organizations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Magnetic flux array for spontaneous magnetic reconnection experiments

Experimental investigation of reconnection in magnetized plasmas relies on accurate characterization of the evolving magnetic fields. In experimental configurations where the plasma dynamics are reproducible, magnetic data can be collected in multiple discharges and combined to provide spatially resolved profiles of the plasma dynamics. However, in experiments on spontaneous magnetic reconnection recently undertaken at the Versatile Toroidal Facility at MIT, the reconnection process is not reproducible and all information on the plasma must be collected in a single discharge. This paper describes a newly developed magnetic flux array which directly measures the toroidal component of the magnetic vector potential, A(phi). From the measured A(phi), the magnetic field geometry, current density, and reconnection rate are readily obtained, facilitating studies of the three-dimensional dynamics of spontaneous magnetic reconnection. The novel design of the probe array allows for accurate characterization of profiles of A(phi) at multiple toroidal angles using a relatively small number of signal channels and with minimal disturbance of the plasma.     

Complete physical map of the common deletion region in Williams syndrome and identification and characterization of three novel genes

Williams syndrome (WS) is a contiguous gene deletion disorder caused by haploinsufficiency of genes at 7q11.23. We have shown that hemizygosity of elastin is responsible for one feature of WS, supravalvular aortic stenosis (SVAS). We have also implicated LIM-kinase 1 hemizygosity as a contributing factor to impaired visual-spatial constructive cognition in WS. However, the common WS deletion region has not been completely characterized, and genes for additional features of WS, including mental retardation, infantile hypercalcemia, and unique personality profile, are yet to be discovered. Here, we present a physical map encompassing 1.5 Mb DNA that is commonly deleted in individuals with WS. Fluorescence in situ hybridization analysis of 200 WS individuals shows that WS individuals have the consistent deletion interval. In addition, we identify three novel genes from the common deletion region: WS-betaTRP, WS-bHLH, and BCL7B. WS-betaTRP has four putative beta-transducin (WD40) repeats, and WS-bHLH is a novel basic helix-loop-helix leucine zipper (bHLHZip) gene. BCL7B belongs to a novel family of highly conserved genes. We describe the expression profile and genomic structure for each of these genes. Hemizygous deletion of one or more of these genes may contribute to developmental defects in WS.     

Structural interaction of natural and synthetic inhibitors with the venom metalloproteinase, atrolysin C (form d)

The structure of the metalloproteinase and hemorrhagic toxin atrolysin C form d (EC 3.4.24.42), from the venom of the western diamondback rattlesnake Crotalus atrox, has been determined to atomic resolution by x-ray crystallographic methods. This study illuminates the nature of inhibitor binding with natural (< Glu-Asn-Trp, where < Glu is pyroglutamic acid) and synthetic (SCH 47890) ligands. The primary specificity pocket is exceptionally deep; the nature of inhibitor and productive substrate binding is discussed. Insights gained from the study of these complexes facilitate the design of potential drugs to treat diseases where matrix metalloproteinases have been implicated, e.g., arthritis and tumor metastasis.     

模块化风机机械动力传动装置的先进解决方案

时下模块化风机齿轮箱的可靠性是一个普遍存在的问题。为此,Maag开发和试制了一种新型Maag DPPV-7-79齿轮箱,在平衡刚度和柔性的基础上能更好地实现载荷的分配均匀,具有较小的应力和最佳齿轮接触模式。     

Fractal feature analysis and classification in medical imaging

Following B.B. Mandelbrot's fractal theory (1982), it was found that the fractal dimension could be obtained in medical images by the concept of fractional Brownian motion. An estimation concept for determination of the fractal dimension based upon the concept of fractional Brownian motion is discussed. Two applications are found: (1) classification; (2) edge enhancement and detection. For the purpose of classification, a normalized fractional Brownian motion feature vector is defined from this estimation concept. It represented the normalized average absolute intensity difference of pixel pairs on a surface of different scales. The feature vector uses relatively few data items to represent the statistical characteristics of the medial image surface and is invariant to linear intensity transformation. For edge enhancement and detection application, a transformed image is obtained by calculating the fractal dimension of each pixel over the whole medical image. The fractal dimension value of each pixel is obtained by calculating the fractal dimension of 7x7 pixel block centered on this pixel.     

Dynamic delayed detached eddy simulation of a multi‐inlet vortex reactor

The multi‐inlet vortex reactor (MIVR) is used for flash nanoprecipitation to manufacture functional nanoparticles. A validated computational fluid dynamics model is needed for the design, scale‐up, and optimization of the MIVR. Unfortunately, available Reynolds‐averaged Navier‐Stokes methods are unable to accurately model the highly swirling flow in the MIVR. Large‐eddy simulations (LES) are also problematic, as excessively fine grids are required to accurately model this flow. These dilemmas led to the application of the dynamic delayed detached eddy simulation (DDES) method to the MIVR. In the dynamic DDES model, the eddy viscosity has a form similar to the Smagorinsky sub‐grid viscosity in LES, which allows the implementation of a dynamic procedure to determine its model coefficient. Simulation results using the dynamic DDES model are found to match well with experimental data in terms of mean velocity and turbulence intensity, suggesting that the dynamic DDES model is a good option for modeling the turbulent swirling flow in the MIVR. © 2016 American Institute of Chemical Engineers AIChE J, 62: 2570–2578, 2016     

Direct comparison of Eulerian–Eulerian and Eulerian–Lagrangian simulations for particle-laden vertical channel flow

Particle-laden flows in a vertical channel were simulated using an Eulerian–Eulerian, Anisotropic Gaussian (EE-AG) model. Two sets of cases varying the overall mass loading were done using particle sizes corresponding to either a large or small Stokes number. Primary and turbulent statistics were extracted from these results and compared with counterparts collected from Eulerian–Lagrangian (EL) simulations. The statistics collected from the small Stokes number particle cases correspond well between the two models, with the EE-AG model replicating the transition observed using the EL model from shear-induced turbulence to relaminarization to cluster-induced turbulence as the mass loading increased. The EE-AG model was able to capture the behavior of the EL simulations only at the largest particle concentrations using the large Stokes particles. This is due to the limitations involved with employing a particle-phase Eulerian model (as opposed to a Lagrangian representation) for a spatially intermittent system that has a low particle number concentration.     

Mimicking Spray Drying by Drying of Single Droplets Deposited on a Flat Surface

The inactivation of bioactive ingredients during spray drying is often matrix specific. Therefore, the design of new processes or the optimisation of existing spray drying processes is usually highly product specific and requires numerous experiments. Rapid experimentation methods that facilitate fast data generation are therefore desired. A novel method for drying single droplets to mimic spray drying is proposed. The approach involves droplet deposition on a hydrophobic flat surface followed by controlled drying. A heat and mass transfer model is applied to predict the drying history of the single droplets. The approach is successfully evaluated through studying the inactivation of β-galactosidase during drying. The heat and mass transfer model supplemented with inactivation kinetics provided reasonable prediction of the residual enzyme activity after drying. In addition, the inactivation kinetics could be directly extracted from single droplet experiments rather than using the kinetics from separate heating experiments. Finally, it was demonstrated that the inactivation kinetics found with the single-drop experiments could satisfactorily predict the residual activity of β-galactosidase dried with a laboratory-scale spray dryer.