Unconstraining Graph-Constrained Group Testing

In network tomography, one goal is to identify a small set of failed links in a network using as little information as possible. One way of setting up this problem is called graph-constrained group testing. Graph-constrained group testing is a variant of the classical combinatorial group testing problem, where the tests that one is allowed are additionally constrained by a graph. In this case, the graph is given by the underlying network topology. The main contribution of this work is to show that for most graphs, the constraints imposed by the graph are no constraint at all. That is, the number of tests required to identify the failed links in graph-constrained group testing is near-optimal even for the corresponding group testing problem with no graph constraints. Our approach is based on a simple randomized construction of tests. To analyze our construction, we prove new results about the size of giant components in randomly sparsified graphs. Finally, we provide empirical results which suggest that our connected-subgraph tests perform better not just in theory but also in practice, and in particular perform better on a real-world network topology

Apparatus for sensor failure detection and correction in a gas turbine engine control system

A gas turbine engine control system maintains a selected level of engine performance despite the failure or abnormal operation of one or more engine parameter sensors. The control system employs a continuously updated engine model which simulates engine performance and generates signals representing real time estimates of the engine parameter sensor signals. The estimate signals are transmitted to a control computational unit which utilizes them in lieu of the actual engine parameter sensor signals to control the operation of the engine. The estimate signals are also compared with the corresponding actual engine parameter sensor signals and the resulting difference signals are utilized to update the engine model. If a particular difference signal exceeds specific tolerance limits, the difference signal is inhibited from updating the model and a sensor failure indication is provided to the engine operator

On the fate of early endosomes

Proteins are endocytosed by various pathways into the cell. All these pathways converge at the level of the early endosome. The fate of the early endosome and how proteins are sorted into recycling and late endosomes/multi-vesicular body is a matter of debate and intense research. Obviously, the transition from early to late endosome poses an interesting logistic problem and would merit attention on an intellectual level. Numerous diseases are also caused by defects in turning off/over signaling molecules or mis-sorting of proteins at the level of the early endosome. This brief review aims to discuss different molecular mechanisms whereby early-to-late endosome transition could be achieve

Membrane Tethering Complexes in the Endosomal System

Vesicles that are generated by endocytic events at the plasma membrane are destined to early endosomes. A prerequisite for proper fusion is the tethering of two membrane entities. Tethering of vesicles to early endosomes is mediated by the CORVET complex, while fusion of late endosomes with lysosomes depends on the HOPS complex. Recycling through the TGN and to the plasma membrane is facilitated by the GARP and EARP complexes, respectively. However, there are other tethering functions in the endosomal system as there are multiple pathways through which proteins can be delivered from endosomes to either the TGN or the plasma membrane. Furthermore, complexes that may be part of novel tethering complexes have been recently identified. Thus it is likely that more tethering factors exist. In this review, I will provide an overview of different tethering complexes of the endosomal system and discuss how they may provide specificity in membrane traffic

Membrane traffic in the secretory pathway: The life cycle of a transport vesicle

Abstract.: Vesicular transport is the basic communication mechanism between different compartments in a cell and with the environment. In this review I discuss the principles of vesicle generation and consumption with particular emphasis on the different types of coat proteins and the timing of the shedding of the coat proteins from transport containers. In recent years it has become clear that there are more coat complexes than the classical COPI, COPII and clathrin coats. These additional coats may generate vesicles that transport cargo in a temporally and/or spatially controlled manner. Work over the last years suggests that GTP hydrolysis occurs early during vesicle biogenesis, destabilizing the coat perhaps before fission of the vesicle from the donor membrane occurs. Recent findings imply, however, that tethers at the receiving compartment specifically detect the coat on vesicle. (Part of a Multi-author Review

Robust Estimation of Surface Curvature Information from Point Cloud Data

This paper surveys and evaluates some popular state of the art methods for algorithmic curvature and normal estimation. In addition to surveying existing methods we also propose a new method for robust curvature estimation and evaluate it against existing methods thus demonstrating its superiority to existing methods in the case of significant data noise. Throughout this paper we are concerned with computation in low dimensional spaces (N < 10) and primarily focus on the computation of the Weingarten map and quantities that may be derived from this; however, the algorithms discussed are theoretically applicable in any dimension. One thing that is common to all these methods is their basis in an estimated graph structure. For any of these methods to work the local geometry of the manifold must be exploited; however, in the case of point cloud data it is often difficult to discover a robust manifold structure underlying the data, even in simple cases, which can greatly influence the results of these algorithms. We hope that in pushing these algorithms to their limits we are able to discover, and perhaps resolve, many major pitfalls that may affect potential users and future researchers hoping to improve these methodsComment: 16 pages, 13 figure

An Examination of the Uses and Gratifications of Utilitarian and Experiential Online Shoppers

As money being spent on e-commerce continues to rise, marketers and retailers are interested in what motivates people to shop online. In the past shoppers have been broken up into two categories, utilitarian or experiential (e.g., O\u27Brien, 2010; Overby & Lee, 2006; To, Liao, & Lin, 2007; Wolfinbarger & Gilly, 2001). The purpose of this study is to evaluate both categories of shoppers by utilizing a uses and gratifications theory framework. Online survey method is utilized to determine if there are differences between the utilitarian and experiential online shoppers in terms of uses sought. As a result, of the five variables that were tested, information, social interaction, identification with e-commerce community, and escapism are all found to be gratifications that both utilitarian and experiential online shoppers desire, however the data for the entertainment variable was inconclusive. This information can be used to inform future e-commerce marketplaces and marketers of how to best target shoppers in an online setting

Dealing with Disagreement: Towards a Conception of Feasible Compromise

The goal of this dissertation is to specify the feasibility conditions of compromise. More specifically, the goal of this dissertation is to specify the conditions of increasing the feasibility of compromise. The underlying assumption here is that feasibility is a scalar concept, meaning that a socio-political ideal can be feasible to different degrees (Lawford-Smith 2013). In order to specify the conditions of increasing the feasibility of compromise, it is necessary to first identify potential feasibility constraints. The main chapters of this dissertation are devoted to this task. My research identifies two kinds of feasibility constraints that compromise potentially faces: A psychological feasibility constraint on realizing moral compromise (i.e. compromise on moral issues) and a structural feasibility constraint on realizing fair compromise. The psychological feasibility constraint consists in what I call an “affective aversion” to compromise. Affective aversion designates a deep emotional reluctance to compromise on moral values, which, I propose, can be reduced by cultivating an affective attitude of respect for other persons. The structural feasibility constraint refers to the process through which a compromise is achieved. I argue that if a fair compromise is the goal, the process of compromising needs to be based on deliberation rather than on the negotiation or bargaining processes that are commonly associated with compromise. Based on these results, my research indicates a) that an affective cultivation of respect is a condition for increasing the feasibility of moral compromise; and b) that deliberation, not negotiation or bargaining, is a condition for increasing the feasibility of fair compromise