1,596 research outputs found
Distributed PC Based Routers: Bottleneck Analysis and Architecture Proposal
No full textRecent research in the different functional areas of modern routers have made proposals that can greatly increase the efficiency of these machines. Most of these proposals can be implemented quickly and often efficiently in software. We wish to use personal computers as forwarders in a network to utilize the advances made by researchers. We therefore examine the ability of a personal computer to act as a router. We analyze the performance of a single general purpose computer and show that I/O is the primary bottleneck. We then study the performance of distributed router composed of multiple general purpose computers. We study the performance of a star topology and through experimental results we show that although its performance is good, it lacks flexibility in its design. We compare it with a multistage architecture. We conclude with a proposal for an architecture that provides us with a forwarder that is both flexible and scalable.© IEE
Lattice-boltzmann very large eddy simulation of a multi-orifice acoustic liner with turbulent grazing flow
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CONSTRUCTION OF CHAOTIC MAPS ON NONCONVEX SPACES — A SOLUTION TO A CSK DECIPHERING PROBLEM
No full text In this paper, we propose a solution to one of the problems raised by the authors [Manjunath & Fournier-Prunaret, 2009a] with regard to a deciphering issue in the chaos shift keying technique. Here, we construct maps on nonconvex spaces using a class of chaotic maps on the (closed) unit square and prove that they exhibit chaos. The constructed maps serve as a practical solution to control the deciphering errors in chaos shift keying. </jats:p
Localization of Synthetic Manipulations in Western Blot Images
No full textRecent breakthroughs in deep learning and generative systems have significantly fostered the creation of synthetic media, as well as the local alteration of real content via the insertion of highly realistic synthetic manipulations. Local image manipulation, in particular, poses serious challenges to the integrity of digital content and societal trust. This problem is not only confined to multimedia data, but also extends to biological images included in scientific publications, like images depicting Western blots. In this work, we address the task of localizing synthetic manipulations in Western blot images. To discriminate between pristine and synthetic pixels of an analyzed image, we propose a synthetic detector that operates on small patches extracted from the image. We aggregate patch contributions to estimate a tampering heatmap, highlighting synthetic pixels out of pristine ones. Our methodology proves effective when tested over two manipulated Western blot image datasets, one altered automatically and the other manually by exploiting advanced AI-based image manipulation tools that are unknown at our training stage. We also explore the robustness of our method over an external dataset of other scientific images depicting different semantics, manipulated through unseen generation techniques. We release our experimental code and the manipulated datasets at https://github.com/polimiispl/western-blot-synthetic-manipulation-localization
GazeVideoAnalyser: A modular software approach towards automatic annotation of gaze videos
No full textEssig K, Abashidze D, Manjunath P, Schack T. GazeVideoAnalyser: A modular software approach towards automatic annotation of gaze videos. In: Pfeiffer T, Essig K, eds. Proceedings of the 2nd International Workshop on Vision and Eye Tracking in Natural Environments and Solutions & Algorithms for Gaze Analysis (SAGA 2015). Bielefeld; 2015: 4-6
On range matrices and wireless networks in d dimensions
No full textSuppose that V = {v1, v2, ...vn} is a set of nodes randomly (uniformly) distributed in the d dimensional cube [0, x0]d, and W = {w(i, j) > 0 : 1 ≤ i, j ≤ n} is a set of numbers chosen so that w(i, j) = w(j, i) = w(j, i). Construct a graph Gn,d,W whose vertex set is V, and whose edge set consists of all pairs {ui, uj} with || ui - uj || ≤ w(i, j). In the wireless network context, the set V is a set of labeled nodes in the network and W represents the maximum distances between the node pairs for them to be connected. We essentially address the following question: "if G is a graph with vertex set V, what is the probability that G appears as a subgraph in Gn,d,W?" Our main contribution is a closed form expression for this probability under the l∞ norm for any dimension d and a suitably defined probability density function. As a corollary to the above answer, we also answer the question, "what is the probability that Qn,d,W is connected?".© IEE
A conceptual framework for the assessment of integrated energy storage resources
No full textConcerns regarding climate change impacts, energy security and sustainability are key drivers of the growing deployment of renewable energy resources. The variability, uncertainty and intermittency associated with the integration of these resources make the operation of the conventional power grid particularly challenging. Energy storage resources (ESRs) are one of the most promising solutions to address these challenges. The unique and versatile nature of storage finds its use in applications over a broad time spectrum. Furthermore, fast acting storage helps smoothen out the variable renewable output, minimize spillage of clean energy and manage the steep ramps associated with renewable energy integration. Storage also finds its use across all three domains of the electrical network, i.e., generation, transmission and distribution.
Cost reductions, technological innovations and regulatory initiatives have invigorated the interest in storage. However, the rapid growth of the storage sector is met by daunting challenges to the implementation of storage in the grid, especially since storage is very different from the conventional grid assets. The nature of storage is unique and its implementation has to be treated as such to fully harness the value it brings to the system it is integrated into. To this end, we outline a framework in this thesis for the integration of energy storage resources into the grid. The framework provides a systematic construct to study the various aspects of ESR integration in a system. The framework is comprehensive as it reflects the physical, information, environmental and financial aspects of storage operations. The thrust of the framework is its flexibility to accommodate the wide range of applications that storage provides on different time-scales. Furthermore, the framework explicitly captures the nature of deployment of storage for a particular application and shows the necessary interactions between ESR and the various players that interact with the ESR.
Case studies to illustrate the implementation of the information, environmental and financial layers of the framework are also presented in the thesis. The studies and their results establish that the framework is an extremely useful construct for the development of tools and models to aid in planning and operational studies and the formulation of policy and incentives and as such, is helpful in bringing the vision of energy storage closer to reality.Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2018-05-01The student, Archana Manjunath, accepted the attached license on 2016-04-09 at 13:31.The student, Archana Manjunath, submitted this Thesis for approval on 2016-04-09 at 13:43.This Thesis was approved for publication on 2016-04-13 at 11:07.DSpace SAF Submission Ingestion Package generated from Vireo submission #9172 on 2016-07-07 at 13:49:01Made available in DSpace on 2016-07-07T20:27:12Z (GMT). No. of bitstreams: 2
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Previous issue date: 2016-04-13Embargo set by: Seth Robbins for item 93095
Lift date: 2018-07-07T20:28:14Z
Reason: Author requested U of Illinois access only (OA after 2yrs) in Vireo ETD systemEmbargo set by: Seth Robbins for item 93095
Lift date: 2018-07-07T20:35:34Z
Reason: Author requested U of Illinois access only (OA after 2yrs) in Vireo ETD systemU of I Only Restriction Lifted for Item 93095 on 2018-07-08T09:15:20Z
Computational Study of the Dynamics of the Flow-Field Induced by Vortex Generators
No full textVortex Generators (VGs) are one of the most commonly used passive flow control devices. Recent studies have shown that it is beneficial to use sub-boundary layer vortex generators (SBVGs). The height of these generators varies between 10% - 50% of the boundary layer thickness. However, the reduced height causes the induced vortices to be substantially weaker. Therefore, using SBVG is beneficial only when the regions of flow separation are well defined. To better understand and comprehensively predict the effectiveness of these devices for flow control over a range of operating conditions, two different SBVG profile: rectangular vortex generators (RVGs) and triangular vortex generators (TVGs) are analysed when subjected to a laminar boundary layer. The topics of interest are instantaneous flow, mean flow, far-field acoustic properties and influence of the angle of attack on the VG vane. The results emphasise the unsteady nature of the induced vortices for both the VG profiles. For RVGs, mean flow visualisation indicates the presence of local re-circulation zones in between the vanes with an increase in angle of attack. Additionally, secondary vortices are noted for both the VGs. These secondary vortices significantly influence the properties of the primary vortices thereby, suggesting that, effectively managing the secondary vortices using suitable design changes to VG profile could be one of the possible ways to accomplish better flow control.Aerospace Engineerin
Experimental Demonstration of the Concept of Endothermic Fuels for Providing Efficient Cooling to Scramjet Combustors
No full textThe development of endothermic fuels is important for providing efficient cooling to scramjet combustors operating at high Mach numbers. Generally the fuel itself can be used as coolant for the engine elements. Since preheating the fuel is desirable before combustion, it can be circulated in heat transfer passages em-bedded inside the hot engine parts so that the excess heat of the engine is removed by the fuel and in the process the fuel is also regeneratively preheated to the desired temperature. Endo-thermic fuels pertain to a class of fuels, which make use of certain endothermic reactions to provide an additional heat sink for cooling the engine hot end parts through embedded heat ex-change devices. While traditional fuels use only the sensible heat of the fuels for cooling, endothermic fuels provide cooling through two routes, namely, the absorption of the sensible heat and through the use of endothermic reactions. At the Propulsion Division, NAL, the concept of endothermic cooling has been ex-perimentally demonstrated using kerosene as the fuel and molec-ular sieves as the cracking catalyst. A laboratory scale catalytic reactor was used for carrying out the catalytic reaction. A differ-ence of 114 K was observed for endothermic cooling whereas the conventional method of cooling gave only 18 K. The details of this important experiment are described in this pape
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