93 research outputs found
A Simple and Efficient RSS-AOA Based Localization with Heterogeneous Anchor Nodes
Accurate and reliable localization is crucial for various wireless
communication applications. Numerous studies have proposed accurate
localization methods using hybrid received signal strength (RSS) and angle of
arrival (AOA) measurements. However, these studies typically assume identical
measurement noise distributions for different anchor nodes, which may not
accurately reflect real-world scenarios with varying noise distributions. In
this paper, we propose a simple and efficient localization method based on
hybrid RSS-AOA measurements that accounts for the varying measurement noises of
different nodes. We derive a closed-form estimator for the target location
based on the linear weighted least squares (LWLS) algorithm, with each LWLS
equation weight being the inverse of its residual variance. Due to the unknown
variances of LWLS equation residuals, we employ a two-stage LWLS method for
estimation. The proposed method is computationally efficient, adaptable to
different types of wireless communication systems and environments, and
provides more accurate and reliable localization results compared to existing
RSS-AOA localization techniques. Additionally, we derive the Cramer-Rao Lower
Bound (CRLB) for the RSS-AOA signal sequences used in the proposed method.
Simulation results demonstrate the superiority of the proposed method
In situ study of the mechanical properties of airborne haze particles
Particulate pollution has raised serious concerns regarding its potential impacts on human health in developing countries. However, much less attention has been paid to the threat of haze particles to machinery and industry. By employing a state-of-the-art in situ scanning electron microscope compression testing technique, we demonstrate that iron-rich and fly ash haze particles, which account for nearly 70% of the total micron-sized spherical haze particles, are strong enough to generate abrasive damage to most engineering alloys, and therefore can generate significant scratch damage to moving contacting surfaces in high precision machineries. Our finding calls for preventive measures to protect against haze related threat.National Basic Research Program of China (973 Program) (Grant 2012CB619402)National 111 Project of China (Grant B06025)National Science Foundation (U.S.) (Grants DMR-1120901 and DMR-1410636)National Natural Science Foundation (China) (Grants 51231005, 51471128 and 51321003
Accurate RSS-Based Localization Using an Opposition-Based Learning Simulated Annealing Algorithm
Wireless sensor networks require accurate target localization, often achieved
through received signal strength (RSS) localization estimation based on maximum
likelihood (ML). However, ML-based algorithms can suffer from issues such as
low diversity, slow convergence, and local optima, which can significantly
affect localization performance. In this paper, we propose a novel localization
algorithm that combines opposition-based learning (OBL) and simulated annealing
algorithm (SAA) to address these challenges. The algorithm begins by generating
an initial solution randomly, which serves as the starting point for the SAA.
Subsequently, OBL is employed to generate an opposing initial solution,
effectively providing an alternative initial solution. The SAA is then executed
independently on both the original and opposing initial solutions, optimizing
each towards a potential optimal solution. The final solution is selected as
the more effective of the two outcomes from the SAA, thereby reducing the
likelihood of the algorithm becoming trapped in local optima. Simulation
results indicate that the proposed algorithm consistently outperforms existing
algorithms in terms of localization accuracy, demonstrating the effectiveness
of our approach
A New Comparison Principle for Impulsive Functional Differential Equations
We establish a new comparison principle for impulsive differential systems with time delay. Then, using this comparison principle, we obtain some sufficient conditions for several stabilities of impulsive delay differential equations. Finally, we present an example to show the effectiveness of our results
novoPathFinder: a webserver of designing novel-pathway with integrating GEM-model
To increase the number of value-added chemicals that can be produced by metabolic engineering and synthetic biology, constructing metabolic space with novel reactions/pathways is crucial. However, with the large number of reactions that existed in the metabolic space and complicated metabolisms within hosts, identifying novel pathways linking two molecules or heterologous pathways when engineering a host to produce a target molecule is an arduous task. Hence, we built a user-friendly web server, novoPathFinder, which has several features: (i) enumerate novel pathways between two specified molecules without considering hosts; (ii) construct heterologous pathways with known or putative reactions for producing target molecule within Escherichia coli or yeast without giving precursor; (iii) estimate novel pathways with considering several categories, including enzyme promiscuity, Synthetic Complex Score (SCScore) and LD50 of intermediates, overall stoichiometric conversions, pathway length, theoretical yields and thermodynamic feasibility. According to the results, novoPathFinder is more capable to recover experimentally validated pathways when comparing other rule-based web server tools. Besides, more efficient pathways with novel reactions could also be retrieved for further experimental exploration. novoPathFinder is available at http://design.rxnfinder.org/novopathfinder/
Model-Driven Remote Attestation: Attesting Remote System from Behavioral Aspect
Ministry of Education, Singapore under its Academic Research Funding Tier 1, Singapore Management Universit
Text mining for identifying topics in the literatures about adolescent substance use and depression
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