HEA-Loc: A robust localization algorithm for sensor networks of diversified topologies

In recent years, localization in a variety of Wireless Sensor Networks (WSNs) is a compelling but elusive goal. Several algorithms that use different methodologies have been proposed to achieve this goal. The performances of these algorithms depend on several factors, such as the sensor node placement, anchor deployment or network topology. In this paper, we propose a robust localization algorithm called Hybrid Efficient and Accurate Localization (HEA-Loc). HEA-Loc combines two techniques, Extended Kalman Filter (EKF) and Proximity-Distance Map (PDM) to improve localization accuracy. It is distributed in nature and works well in various scenarios as it is less susceptible to anchors deployment and the network topology. Furthermore, HEA-Loc has strong robustness and it can work well even the measurement errors are large. Simulation results show that HEA-Loc outperforms existing algorithms in both computational complexity and communication overhead. ©2010 IEEE.published_or_final_versionThe IEEE Wireless Communications and Networking Conference (WCNC 2010), Sydney, NSW., 18-21 April 2010. In Proceedings of WCNC, 2010, p. 1-

A new ILP-based p-cycle construction algorithm without candidate cycle enumeration

The notion of p-cycle (Preconfigured Protection Cycle) allows capacity efficient schemes to be designed for fast span protection in WDM mesh networks. Conventional p-cycle construction algorithms need to enumerate/pre-select candidate cycles before ILP (Integer Linear Program) can be applied. In this paper, we propose a new algorithm which is only based on ILP. When the required number of p-cycles is not too large, our ILP can generate optimal/suboptimal solutions in reasonable amount of running time. © 2007 IEEE.published_or_final_versio

Efficient Communication of Sensors Monitoring Overhead Transmission Lines

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Formal Availability Analysis using Theorem Proving

Availability analysis is used to assess the possible failures and their restoration process for a given system. This analysis involves the calculation of instantaneous and steady-state availabilities of the individual system components and the usage of this information along with the commonly used availability modeling techniques, such as Availability Block Diagrams (ABD) and Fault Trees (FTs) to determine the system-level availability. Traditionally, availability analyses are conducted using paper-and-pencil methods and simulation tools but they cannot ascertain absolute correctness due to their inaccuracy limitations. As a complementary approach, we propose to use the higher-order-logic theorem prover HOL4 to conduct the availability analysis of safety-critical systems. For this purpose, we present a higher-order-logic formalization of instantaneous and steady-state availability, ABD configurations and generic unavailability FT gates. For illustration purposes, these formalizations are utilized to conduct formal availability analysis of a satellite solar array, which is used as the main source of power for the Dong Fang Hong-3 (DFH-3) satellite.Comment: 16 pages. arXiv admin note: text overlap with arXiv:1505.0264

Restoration of optic neuropathy

Optic neuropathy refers to disorders involving the optic nerve (ON). Any damage to ON or ON-deriving neurons, the retinal ganglion cells (RGCs), may lead to the breakdown of the optical signal transmission from the eye to the brain, thus resulting in a partial or complete vision loss. The causes of optic neuropathy include trauma, ischemia, inflammation, compression, infiltration, and mitochondrial damages. ON injuries include primary and secondary injuries. During these injury phases, various factors orchestrate injured axons to die back and become unable to regenerate, and these factors could be divided into two categories: extrinsic and intrinsic. Extrinsic inhibitory factors refer to the environmental conditions that influence the regeneration of injured axons. The presence of myelin inhibitors and glial scar, lack of neurotrophic factors, and inflammation mediated by injury are regarded as these extrinsic factors. Extrinsic factors need to trigger the intracellular signals to exert inhibitory effect. Proper regulation of these intracellular signals has been shown to be beneficial to ON regeneration. Intrinsic factors of RGCs are the pivotal reasons that inhibit ON regeneration and are closely linked with extrinsic factors. Intracellular cyclic adenosine monophosphate (cAMP) and calcium levels affect axon guidance and growth cone response to guidance molecules. Many genes, such as Bcl-2, PTEN, and mTOR, are crucial in cell proliferation, axon guidance, and growth during development, and play important roles in the regeneration and extension of RGC axons. With transgenic mice and related gene regulations, robust regeneration of RGC axons has been observed after ON injury in laboratories. Although various means of experimental treatments such as cell transplantation and gene therapy have achieved significant progress in neuronal survival, axonal regeneration, and restoration of the visual function after ON injury, many unresolved scientific problems still exist for their clinical applications. Therefore, we still need to overcome hurdles before developing effective therapy to treat optic neuropathy diseases in patients.published_or_final_versio

Efficient hardware architecture for fast IP address lookup

A multigigabit IP router may receive several millions packets per second from each input link. For each packet, the router needs to find the longest matching prefix in the forwarding table in order to determine the packet's next-hop. In this paper, we present an efficient hardware solution for the IP address lookup problem. We model the address lookup problem as a searching problem on a binary-trie. The binary-trie is partitioned into four levels of fixed size 255-node subtrees. We employ a hierarchical indexing structure to facilitate direct access to subtrees in a given level. It is estimated that a forwarding table with 40K prefixes will consume 2.5Mbytes of memory. The searching is implemented using a hardware pipeline with a minimum cycle of 12.5ns if the memory modules are implemented using SRAM. A distinguishing feature of our design is that forwarding table entries are not replicated in the data structure. Hence, table updates can be done in constant time with only a few memory accesses.published_or_final_versio

Search for pulsed γ-ray emission from globular cluster M28

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Exploring the X-ray and γ-ray properties of the redback millisecond pulsar PSR J1723-2837

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Orbital-phase-dependent γ-ray Emissions from the Black Widow Pulsar

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CHANDRA DETECTION OF A NEW DIFFUSE X-RAY COMPONENT FROM THE GLOBULAR CLUSTER 47 TUCANAE

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