Efficient method for calculating the transmission coefficient of two-dimensional quantum wire structures

We present a very simple and efficient method for calculating the transmission coefficient of two-dimensional quantum wire structures based on the time-dependent solution of the Schrödinger equation. We apply the new method to a specific two-dimensional quantum wire structure. The new method is much faster than the finite element method and can be used to study electron transport in the presence of electron–phonon interaction and nonlinear interactions in the Schrödinger equation. ©1996 American Institute of Physics.published_or_final_versio

Range Queries on Uncertain Data

Given a set $P$ of $n$ uncertain points on the real line, each represented by its one-dimensional probability density function, we consider the problem of building data structures on $P$ to answer range queries of the following three types for any query interval $I$: (1) top-$1$ query: find the point in $P$ that lies in $I$ with the highest probability, (2) top-$k$ query: given any integer $k\leq n$ as part of the query, return the $k$ points in $P$ that lie in $I$ with the highest probabilities, and (3) threshold query: given any threshold $\tau$ as part of the query, return all points of $P$ that lie in $I$ with probabilities at least $\tau$. We present data structures for these range queries with linear or nearly linear space and efficient query time.Comment: 26 pages. A preliminary version of this paper appeared in ISAAC 2014. In this full version, we also present solutions to the most general case of the problem (i.e., the histogram bounded case), which were left as open problems in the preliminary versio

Efficient notification of meeting points for moving groups via independent safe regions

In applications like social networking services and online games, multiple moving users form a group and wish to be continuously notified with the best meeting point from their locations. To reduce the communication frequency of the application server, a promising technique is to apply safe regions, which capture the validity of query results with respect to the users' locations. Unfortunately, the safe regions in our problem exhibit characteristics such as irregular shapes and dependency among multiple safe regions. These unique characteristics render existing safe region methods that focus on a single safe region inapplicable to our problem. To tackle these challenges, we first examine the shapes of safe regions in our problem context and propose feasible approximations for them. We design efficient algorithms for computing these safe regions, as well as develop compression techniques for representing safe regions in a compact manner. Experiments with both real and synthetic data demonstrate the efficiency of our proposal in terms of computation and communication costs. © 2013 IEEE.published_or_final_versio

System-state-free false data injection attack for nonlinear state estimation in smart grid

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Real-time GPU-based adaptive beamformer for high quality ultrasound imaging

Poster Session Session P1Aa. Beam Formation: Computational Aspects And Artifact Reduction: no. P1Ac-7A real-time adaptive minimum variance (MV) beam-former realized using graphics processing units (GPUs) is presented. MV adaptive beamforming technique is attractive as it is capable of producing high quality images with narrow mainlobe width and low sidelobe level. However, because of its substantially higher computational requirements, realizing MV in real-time has been prohibitively difficult. Recent advancements in commodity GPUs have made very high performance computing possible at very affordable price. Using a commercial off-the-shelf GPU, an MV beam-former achieving real-time performance has been realized. Tradeoffs between computational throughput and image quality have been studied. Careful selection of algorithm parameters, including receive aperture and sub-aperture size, was demonstrated to be imperative for achieving real-time performance without sacrificing image qualities.published_or_final_versionThe 2011 IEEE International Ultrasonics Symposium (IUS), Orlando, FL., 18-21 October 2011. In IEEE International Ultrasonics Symposium Proceedings, 2011, p. 474-47

Secure end-to-end browsing system with mobile composition

To fix the more and more serious leakage problem in remote access to confidential data, the paper designs and implements a secure end-to-end browsing system with mobile composition. It enables mobile-authenticated users to browse confidential files stored at server side using their personal computers securely. The authentication function is in real-time such that the system can stop the browsing function once it detects that the authenticated mobile is out of the communication range of user's personal computer. © 2011 IEEE.published_or_final_versio

Efficient Notification of Meeting Points for Moving Groups via Independent Safe Regions

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Medical ultrasound imaging: To GPU or not to GPU?

Medical ultrasound imaging stands out from other modalities in providing real-time diagnostic capability at an affordable price while being physically portable. This article explores the suitability of using GPUs as the primary signal and image processors for future medical ultrasound imaging systems. A case study on synthetic aperture (SA) imaging illustrates the promise of using high-performance GPUs in such systems. © 2011 IEEE.published_or_final_versio