Han Zheng

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Internet coordinate systems embed Round-Trip-Times (RTTs) between Internet nodes into some geometric space so that unmeasured RTTs can be estimated using distance computation in that space. If accurate, such techniques would allow us to predict Internet RTTs without extensive measurements. The published techniques appear to work very well when accuracy is(More)
Round trip times (RTTs) play an important role in Internet measurements. In this paper, we explore some of the ways in which routing policies impact RTTs. In particular, we investigate how routing policies for both intra-and inter-domain routing can naturally give rise to violations of the triangle inequality with respect to RTTs. Triangle Inequality(More)
This paper presents a new technique for noise cancellation and signal separation, which is capable of identifying channel dynamics in real time, removing noise effectively, and separating source signals by reconfiguring signal transmission channels during different phases of source signals. This method is motivated by extracting authentic heart and lung(More)
Cognitive Radio is considered as a potential solution to improve spectrum utilization via opportunistic spectrum sharing. In this paper, we present a software testbed which is developed to implement the cognitive radio system. The basic functions of cognitive radio are explored and implemented, including spectrum sensing and dynamic spectrum management. The(More)
Noises are one of the key obstacles in applying continuous monitoring and computer-assisted analysis of respiratory sounds in operating rooms. This paper introduces a new methodology for extracting authentic lung sounds from a noisy environment. This methodology utilizes the unique feature of time-split stages in breathing sounds, rather than frequency(More)
Born-Oppenheimer ab initio QM/MM molecular dynamics simulation with umbrella sampling is a state-of-the-art approach to calculate free energy profiles of chemical reactions in complex systems. To further improve its computational efficiency, a mass-scaling method with the increased time step in MD simulations has been explored and tested. It is found that(More)
Automatic extraction of road curbs from uneven, unorganized, noisy and massive 3D point clouds is a challenging task. Existing methods often project 3D point clouds onto 2D planes to extract curbs. However, the projection causes loss of 3D information which degrades the performance of the detection. This paper presents a robust, accurate and efficient(More)
As the user's identity and sensitive information are regularly used in the process of cloud service access control, there will be a need to protect the user privacy from disclosing to cloud provider. This paper describes a new access control policy based on group signatures in cloud service, which allows users to access the cloud services on behalf of group(More)
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