Predicting Controller Capacity in Supervisory Control of Multiple UAVs

In the future vision of allowing a single operator to remotely control multiple unmanned vehicles, it is not well understood what cognitive constraints limit the number of vehicles and related tasks that a single operator can manage. This paper illustrates that, when predicting the number of unmanned aerial vehicles (UAVs) that a single operator can control, it is important to model the sources of wait times (WTs) caused by human-vehicle interaction, particularly since these times could potentially lead to a system failure. Specifically, these sources of vehicle WTs include cognitive reorientation and interaction WT (WTI), queues for multiple-vehicle interactions, and loss of situation awareness (SA) WTs. When WTs were included, predictions using a multiple homogeneous and independent UAV simulation dropped by up to 67%, with a loss of SA as the primary source of WT delays. Moreover, this paper demonstrated that even in a highly automated management-by-exception system, which should alleviate queuing and WTIs, operator capacity is still affected by the SA WT, causing a 36% decrease over the capacity model with no WT included.     

Adaptive Threat Modeling for Secure Ad Hoc Routing Protocols

Secure routing protocols for mobile ad hoc networks provide the required functionality for proper network operation. If the underlying routing protocol cannot be trusted to follow the protocol operations, additional trust layers, such as authentication, cannot be obtained. Threat models drive analysis capabilities, affecting how we evaluate trust. Current attacker threat models limit the results obtained during protocol security analysis over ad hoc routing protocols. Developing a proper threat model to evaluate security properties in mobile ad hoc routing protocols presents a significant challenge. If the attacker strength is too weak, we miss vital security flaws. If the attacker strength is too strong, we cannot identify the minimum required attacker capabilities needed to break the routing protocol. In this paper we present an adaptive threat model to evaluate route discovery attacks against ad hoc routing protocols. Our approach enables us to evaluate trust in the ad hoc routing process and allows us to identify minimum requirements an attacker needs to break a given routing protocol.     

Low temperature thermal conductivity of twinned and untwinned indium-thallium alloys

The low-temperature lattice thermal conductivity of twinned and untwinned, martensitic and non-martensitic, indium-thallium alloys has been measured to probe the effect of twin boundaries on phonon thermal transport. The phonon scattering by electrons, sample surfaces, dislocations, and thallium impurities is accounted for adequately by existing theoretical models. The reduced lattice thermal conductivity seen in twinned samples is attributed to additional phonon scattering by twin boundaries and, for the polycrystalline samples, by grain boundaries. Phonon scattering by twin boundaries is much weaker than that generally reported for grain boundaries, and is well represented by an acoustic-mismatch model.     

Edge location to subpixel values in digital imagery

A new method for locating edges in digital data to subpixel values and which is invariant to additive and multiplicative changes in the data is presented. For one-dimensional edge patterns an ideal edge is fit to the data by matching moments. It is shown that the edge location is related to the so-called ``Christoffel numbers.' Also presented is the study of the effect of additive noise on edge location. The method is extended to include two-dimensional edge patterns where a line equation is derived to locate an edge. This in turn is compared with the standard Hueckel edge operator. An application of the new edge operator as an edge detector is also provided and is compared with Sobel and Hueckel edge detectors in presence and absence of noise.     

A new algorithm for shortest paths among obstacles in the plane

We introduce a new algorithm for computing Euclidean shortest paths in the plane in the presence of polygonal obstacles. In particular, for a given start points, we build a planar subdivision (ashortest path map) that supports efficient queries for shortest paths froms to any destination pointt. The worst-case time complexity of our algorithm isO(kn log² n), wheren is the number of vertices describing the polygonal obstacles, andk is a parameter we call the illumination depth of the obstacle space. Our algorithm usesO(n) space, avoiding the possibly quadratic space complexity of methods that rely on visibility graphs. The quantityk is frequently significantly smaller thann, especially in some of the cases in which the visibility graph has quadratic size. In particular,k is bounded above by the number of different obstacles that touch any shortest path froms.Partially supported by NSF Grants IRI-8710858 and ECSE-8857642 and by a grant from Hughes Research Laboratories, Malibu, CA.     

An automated vision based on-line novel percept detection method for a mobile robot

It is generally agreed that learning, either supervised or unsupervised, can provide the best possible specification of known classes and offer inference for outlier detection by a dissimilarity threshold from the nominal feature space. Novel percept detection can take a step further by investigating whether these outliers form new dense clusters in both the feature space and the image space. By defining a novel percept to be a pattern group that has not been seen before in the feature space and the image space, in this paper, a non-conventional approach is proposed for multiple-novel-percept detection problem in robotic applications. Based on a computer vision system inspired loosely by neurobiological evidence, our approach can work in near real time for highly sparse high-dimensional feature vectors extracted from image patches while maintaining robustness to image transformations. Experiments conducted in an indoor environment and an outdoor environment demonstrate the efficacy of our method.     

Smooth Shape‐Aware Functions with Controlled Extrema

Functions that optimize Laplacian‐based energies have become popular in geometry processing, e.g. for shape deformation, smoothing, multiscale kernel construction and interpolation. Minimizers of Dirichlet energies, or solutions of Laplace equations, are harmonic functions that enjoy the maximum principle, ensuring no spurious local extrema in the interior of the solved domain occur. However, these functions are only C⁰ at the constrained points, which often causes smoothness problems. For this reason, many applications optimize higher‐order Laplacian energies such as biharmonic or triharmonic. Their minimizers exhibit increasing orders of continuity but lose the maximum principle and show oscillations. In this work, we identify characteristic artifacts caused by spurious local extrema, and provide a framework for minimizing quadratic energies on manifolds while constraining the solution to obey the maximum principle in the solved region. Our framework allows the user to specify locations and values of desired local maxima and minima, while preventing any other local extrema. We demonstrate our method on the smoothness energies corresponding to popular polyharmonic functions and show its usefulness for fast handle‐based shape deformation, controllable color diffusion, and topologically‐constrained data smoothing.     

Radial distribution functions of non-crystalline polymers and their application to the structural analysis of PMMA

The use of Radial Distribution Functions (RDFs) in the determination of the structure of non-crystalline polymers is briefly reviewed. Particular aspects of the procedure for preparing RDFs from X-ray scattering are discussed in detail; namely the employment of an energy dispersive detector to remove the Compton component of the scattered X-rays and the application of the method of sampled transforms. A RDF is presented for atactic polymethylmethacrylate (PMMA) and its precision and reliability are discussed. It is analysed by comparison with RDFs calculated from computer-generated atom co-ordinates for isolated lengths of PMMA chains in different conformations. Methods are introduced by which the calculated RDFs are smeared to account for random disorder in the real chain and normalized so that, despite the finite range of the model, they can be immediately compared with the difference RDF which is directly obtained by transforming the data. Comparison between experimental and calculated RDFs shows that reasonable agreement is only obtained for a very limited range of conformations corresponding to sequences of backbone bond rotation angles of (10, 10, –10, –10) and the bond angles alternately 110 and 128. The form of the RDF appears very sensitive to important aspects of the molecular structure. The results both confirm and refine an earlier proposal from this laboratory which was based on comparisons between experimental and calculated functions in reciprocal space.     

用开关稳压控制器产生快速脉冲

模拟步进功能的快速上升沿脉冲源可以完成很多有用的实验室测量工作,包括确定同轴电缆上升时间特性,以及用时域反射方法找到电缆故障点。例如,在估算一个10英尺～20英尺长RG-58/U电缆的上升时间时,就需要1ns～2ns的边沿跃升时间。Agilent公司(www．agilent．com)的HP8012B是一个在很多电子实验室中都有使用的,可以承受大量工作负荷的脉冲发生器,它提供具有5 ns上升时间的脉冲,这足以用于许多应用场合,但不适合用于确定电缆特性。     

Alcohol's Effect on Triggered Displaced Aggression.

The authors examined alcohol's effect on triggered displaced aggression, the hostile reaction to a second provoking person after provocation from a first. Participants consumed an alcoholic or a nonalcoholic beverage. Subsequently, one individual provoked all of them with moderate intensity. Then, 2 groups were studied: those who received or who failed to receive a second provocation of minimal intensity. Consistent with prior research, participants who received a second, minimal provocation displayed more aggression than those who did not. After participants drank alcohol, the magnitude of this difference was significantly greater, indicating that alcohol increases triggered displaced aggression. (PsycINFO Database Record (c) 2010 APA, all rights reserved)