14578190
Algorithm for Detection with Localization of Multi-targets in Wireless Acoustic Sensor Networks
In most multitarget tracking approaches based on joint probabilistic data association (JPDA), it is difficult to apply the solutions to problems (due to the dimensionality curse of heavy complexity) where the number of target varies dramatically. In this paper, we introduce an algorithm for detection of multitargets in wireless acoustic sensor networks (ADMAN); we localize detected targets by particle filtering after ADMAN. The purpose of ADMAN is detecting any number of targets (We know the approximate locations of targets during the detection algorithm.) in the field of interest. The advantage of ADMAN is its ability to cope with varying number of targets in time. ADMAN does not have any restrictions on the varying pattern of the target number
15628892
Tracking an Object in 3-D Space using Particle Filtering based on Sensor Array
This paper presents a formulation of particle filter for tracking an object in 3-D space. The 3-D tracking algorithm is derived based on bearings only tracking algorithm that is applied in tracking of an object in 2-D space with one angle measurement. We investigate and present the fusion process of the algorithms. The performance of the proposed algorithms are evaluated in detail.
1639783
High performance asynchronous on-chip bus with multiple issue and out-of-order/in-order completion
In this paper, we propose a high performance asynchronous on-chip bus with multiple issue and in-order/out-of-order completion for a Globally Asynchronous Locally Synchronous (GALS) design. The proposed bus implementation can be characterized with distributed and modularized control units based on a layered architecture to support multiple issue and in-order/out-of-order completion. Simulation results reveal that throughputs of asynchronous on-chip buses with multiple issue and in-order/out-of-order completion increases by 31.3% / 34.3%, while power consumption overhead is only 6.76% / 3.98% respectively, compared to a simple asynchronous on-chip bus with only a single issue feature.
1805893
Secure Localization and Location Verification in Sensor Networks
Evolving networks of wireless sensing nodes have many attractive applications. Localization, that is to determine the locations of sensor nodes, is a key enabler for many applications of sensor networks. As sensor networks move closer to extensive deployments, security becomes a major concern, resulting in a new demand for secure localization and location proving systems. In this paper, we propose a secure localization system based on a secure hop algorithm. A location verification system that allows the base station to verify the locations of sensor nodes is also presented. It prevents a node from falsifying reported location information. The evaluation of the secure localization system shows that the proposed scheme performs well under a range of scenarios tested and is resilient against an attacker creating incorrect location information in other nodes.
11377777
Delayed locking technique for improving real-time performance of embedded Linux by prediction of timer interrupt
In this paper, we propose a new technique, called a delayed locking technique, to improve the real-time performance of embedded Linux. The proposed technique employs the rule that entering a critical section is allowed only if the operation does not disturb the future execution of the real-time application. To execute this rule, we introduce the concepts of timer interrupt prediction and lock hold time acquisition. In addition, we designed and implemented a new high-resolution timer that is simple, yet efficient. We implemented the prototype on Linux 2.4.18. Experimental results show that the worst-case OS latency of real-time process is reduced to 23% of the original one, at the expense of slowdown of the nonreal-time process by 20%. Though we focus only on embedded Linux, our technique is useful for all kinds of real-time operating systems in which the critical section is significantly long.
16485757
Reverse Engineering MAC
This paper reverse engineers backoff-based random-access MAC protocols in ad-hoc networks. We show that the contention resolution algorithm in such protocols is implicitly participating in a non-cooperative game. Each link attempts to maximize a selfish local utility function, whose exact shape is reverse engineered from the protocol description, through a stochastic subgradient method in which the link updates its persistence probability based on its transmission success or failure. We prove that existence of a Nash equilibrium is guaranteed in general. The minimum amount of backoff aggressiveness needed for uniqueness of Nash equilibrium and convergence of the best response strategy are established as a function of user density. Convergence properties and connection with the best response strategy are also proved for variants of the stochastic-subgradient-based dynamics of the game. Together with known results in reverse engineering TCP and BGP, this paper completes the recent efforts in reverse engineering the main protocols in layers 2-4.
7307952
Optimal variable-density k-space sampling in MRI
Magnetic resonance imaging (MRI) is often times limited by scan time. To reduce scan time, there have been various efforts to reduce the number of sampling points. In most cases, this is done by utilizing a priori knowledge of the signal of interest. In this paper, we propose an algorithm that will guide the determination of an optimal sampling pattern based on prior knowledge of the signal. Applications of this method include optimal variable-density k-space trajectory design or reduced phase encoding in 3DFT and spectroscopy. Preliminary results are shown as a proof of concept.