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Sample records for hierarchical tesla wireless

  1. Time Synchronization in Hierarchical TESLA Wireless Sensor Networks

    SciTech Connect

    Jason L. Wright; Milos Manic

    2009-08-01

    Time synchronization and event time correlation are important in wireless sensor networks. In particular, time is used to create a sequence events or time line to answer questions of cause and effect. Time is also used as a basis for determining the freshness of received packets and the validity of cryptographic certificates. This paper presents secure method of time synchronization and event time correlation for TESLA-based hierarchical wireless sensor networks. The method demonstrates that events in a TESLA network can be accurately timestamped by adding only a few pieces of data to the existing protocol.

  2. Nikola Tesla and the wireless transmission of energy

    SciTech Connect

    Marincic, A.S.

    1982-10-01

    Nikola Tesla, the inventor of the polyphase-current system, is best known for his contribution regarding induction and other types of alternating-current machines. His patents and his published and unpublished notes about wireless transmission of energy are less known and, if known to some extent, they are usually wrongly interpreted. For many years the author studied Tesla's works on wireless transmission of energy and that what is given here is a review of relevant documents, unpublished notes and letters from the archives of the Nikola Tesla Museum in Belgrade. An attempt is made to explain Tesla's physical model on the basis of which he concluded that the wireless transmission of energy on a global scale is possible. His model is critically examined in view of the present day knowledge of extremely low frequency propagation phenomena.

  3. A hierarchical wireless sensor network model for structural monitoring system

    NASA Astrophysics Data System (ADS)

    Niu, Jianjun; Deng, Zhidong

    2007-12-01

    Based on the technology of wireless sensor networks, topology planning of a large building structural monitoring system is investigated in this paper. A three-level transmission power model and two constrained premise are built up to form a clustering hierarchy based routing model for low delay and high data rate demands. Aim to minimize total power consumption of the whole system, particle swarm optimization (PSO) algorithm is applied to optimize the power level of each nodes. This optimized topology approach is important to design a more permanent wireless sensor network for structural monitoring system in the initial stage.

  4. Edison vs. Tesla

    ScienceCinema

    Hogan, Kathleen; Wallace, Hal; Ivestor, Rob

    2014-01-07

    As Edison vs. Tesla week heats up at the Energy Department, we are exploring the rivalry between Thomas Edison and Nikola Tesla and how their work is still impacting the way we use energy today. Whether you're on Team Tesla or Team Edison, both inventors were key players in creating things like batteries, power plants and wireless technologies -- all innovations we still use today. And as we move toward a clean energy future, energy efficient lighting, like LED bulbs, and more efficient electric motors not only help us save money on electricity costs but help combat climate change. For this, Tesla and Edison both deserve our recognition.

  5. Edison vs. Tesla

    SciTech Connect

    Hogan, Kathleen; Wallace, Hal; Ivestor, Rob

    2013-11-20

    As Edison vs. Tesla week heats up at the Energy Department, we are exploring the rivalry between Thomas Edison and Nikola Tesla and how their work is still impacting the way we use energy today. Whether you're on Team Tesla or Team Edison, both inventors were key players in creating things like batteries, power plants and wireless technologies -- all innovations we still use today. And as we move toward a clean energy future, energy efficient lighting, like LED bulbs, and more efficient electric motors not only help us save money on electricity costs but help combat climate change. For this, Tesla and Edison both deserve our recognition.

  6. A Complete Hierarchical Key Management Scheme for Heterogeneous Wireless Sensor Networks

    PubMed Central

    Zheng, Xinying

    2014-01-01

    Heterogeneous cluster-based wireless sensor networks (WSN) attracted increasing attention recently. Obviously, the clustering makes the entire networks hierarchical; thus, several kinds of keys are required for hierarchical network topology. However, most existing key management schemes for it place more emphasis on pairwise key management schemes or key predistribution schemes and neglect the property of hierarchy. In this paper, we propose a complete hierarchical key management scheme which only utilizes symmetric cryptographic algorithms and low cost operations for heterogeneous cluster-based WSN. Our scheme considers four kinds of keys, which are an individual key, a cluster key, a master key, and pairwise keys, for each sensor node. Finally, the analysis and experiments demonstrate that the proposed scheme is secure and efficient; thus, it is suitable for heterogeneous cluster-based WSN. PMID:24983001

  7. An Intrusion Detection System Based on Multi-Level Clustering for Hierarchical Wireless Sensor Networks.

    PubMed

    Butun, Ismail; Ra, In-Ho; Sankar, Ravi

    2015-01-01

    In this work, an intrusion detection system (IDS) framework based on multi-level clustering for hierarchical wireless sensor networks is proposed. The framework employs two types of intrusion detection approaches: (1) "downward-IDS (D-IDS)" to detect the abnormal behavior (intrusion) of the subordinate (member) nodes; and (2) "upward-IDS (U-IDS)" to detect the abnormal behavior of the cluster heads. By using analytical calculations, the optimum parameters for the D-IDS (number of maximum hops) and U-IDS (monitoring group size) of the framework are evaluated and presented. PMID:26593915

  8. An Intrusion Detection System Based on Multi-Level Clustering for Hierarchical Wireless Sensor Networks

    PubMed Central

    Butun, Ismail; Ra, In-Ho; Sankar, Ravi

    2015-01-01

    In this work, an intrusion detection system (IDS) framework based on multi-level clustering for hierarchical wireless sensor networks is proposed. The framework employs two types of intrusion detection approaches: (1) “downward-IDS (D-IDS)” to detect the abnormal behavior (intrusion) of the subordinate (member) nodes; and (2) “upward-IDS (U-IDS)” to detect the abnormal behavior of the cluster heads. By using analytical calculations, the optimum parameters for the D-IDS (number of maximum hops) and U-IDS (monitoring group size) of the framework are evaluated and presented. PMID:26593915

  9. Space-Time Hierarchical-Graph Based Cooperative Localization in Wireless Sensor Networks

    NASA Astrophysics Data System (ADS)

    Lv, Tiejun; Gao, Hui; Li, Xiaopeng; Yang, Shaoshi; Hanzo, Lajos

    2016-01-01

    It has been shown that cooperative localization is capable of improving both the positioning accuracy and coverage in scenarios where the global positioning system (GPS) has a poor performance. However, due to its potentially excessive computational complexity, at the time of writing the application of cooperative localization remains limited in practice. In this paper, we address the efficient cooperative positioning problem in wireless sensor networks. A space-time hierarchical-graph based scheme exhibiting fast convergence is proposed for localizing the agent nodes. In contrast to conventional methods, agent nodes are divided into different layers with the aid of the space-time hierarchical-model and their positions are estimated gradually. In particular, an information propagation rule is conceived upon considering the quality of positional information. According to the rule, the information always propagates from the upper layers to a certain lower layer and the message passing process is further optimized at each layer. Hence, the potential error propagation can be mitigated. Additionally, both position estimation and position broadcasting are carried out by the sensor nodes. Furthermore, a sensor activation mechanism is conceived, which is capable of significantly reducing both the energy consumption and the network traffic overhead incurred by the localization process. The analytical and numerical results provided demonstrate the superiority of our space-time hierarchical-graph based cooperative localization scheme over the benchmarking schemes considered.

  10. An energy efficient cooperative hierarchical MIMO clustering scheme for wireless sensor networks.

    PubMed

    Nasim, Mehwish; Qaisar, Saad; Lee, Sungyoung

    2012-01-01

    In this work, we present an energy efficient hierarchical cooperative clustering scheme for wireless sensor networks. Communication cost is a crucial factor in depleting the energy of sensor nodes. In the proposed scheme, nodes cooperate to form clusters at each level of network hierarchy ensuring maximal coverage and minimal energy expenditure with relatively uniform distribution of load within the network. Performance is enhanced by cooperative multiple-input multiple-output (MIMO) communication ensuring energy efficiency for WSN deployments over large geographical areas. We test our scheme using TOSSIM and compare the proposed scheme with cooperative multiple-input multiple-output (CMIMO) clustering scheme and traditional multihop Single-Input-Single-Output (SISO) routing approach. Performance is evaluated on the basis of number of clusters, number of hops, energy consumption and network lifetime. Experimental results show significant energy conservation and increase in network lifetime as compared to existing schemes. PMID:22368459

  11. Decentralized Cooperative TOA/AOA Target Tracking for Hierarchical Wireless Sensor Networks

    PubMed Central

    Chen, Ying-Chih; Wen, Chih-Yu

    2012-01-01

    This paper proposes a distributed method for cooperative target tracking in hierarchical wireless sensor networks. The concept of leader-based information processing is conducted to achieve object positioning, considering a cluster-based network topology. Random timers and local information are applied to adaptively select a sub-cluster for the localization task. The proposed energy-efficient tracking algorithm allows each sub-cluster member to locally estimate the target position with a Bayesian filtering framework and a neural networking model, and further performs estimation fusion in the leader node with the covariance intersection algorithm. This paper evaluates the merits and trade-offs of the protocol design towards developing more efficient and practical algorithms for object position estimation. PMID:23202212

  12. An Energy Efficient Cooperative Hierarchical MIMO Clustering Scheme for Wireless Sensor Networks

    PubMed Central

    Nasim, Mehwish; Qaisar, Saad; Lee, Sungyoung

    2012-01-01

    In this work, we present an energy efficient hierarchical cooperative clustering scheme for wireless sensor networks. Communication cost is a crucial factor in depleting the energy of sensor nodes. In the proposed scheme, nodes cooperate to form clusters at each level of network hierarchy ensuring maximal coverage and minimal energy expenditure with relatively uniform distribution of load within the network. Performance is enhanced by cooperative multiple-input multiple-output (MIMO) communication ensuring energy efficiency for WSN deployments over large geographical areas. We test our scheme using TOSSIM and compare the proposed scheme with cooperative multiple-input multiple-output (CMIMO) clustering scheme and traditional multihop Single-Input-Single-Output (SISO) routing approach. Performance is evaluated on the basis of number of clusters, number of hops, energy consumption and network lifetime. Experimental results show significant energy conservation and increase in network lifetime as compared to existing schemes. PMID:22368459

  13. Double-layer video transmission over decode-and-forward wireless relay networks using hierarchical modulation.

    PubMed

    Nguyen, Tu V; Cosman, Pamela C; Milstein, Laurence B

    2014-04-01

    We consider a wireless relay network with a single source, a single destination, and a multiple relay. The relays are half-duplex and use the decode-and-forward protocol. The transmit source is a layered video bitstream, which can be partitioned into two layers, a base layer (BL) and an enhancement layer (EL), where the BL is more important than the EL in terms of the source distortion. The source broadcasts both layers to the relays and the destination using hierarchical 16-QAM. Each relay detects and transmits successfully decoded layers to the destination using either hierarchical 16-QAM or QPSK. The destination can thus receive multiple signals, each of which can include either only the BL or both the BL and the EL. We derive the optimal linear combining method at the destination, where the uncoded bit error rate is minimized. We also present a suboptimal combining method with a closed-form solution, which performs very close to the optimal. We use the proposed double-layer transmission scheme with our combining methods for transmitting layered video bitstreams. Numerical results show that the double-layer scheme can gain 2-2.5 dB in channel signal-to-noise ratio or 5-7 dB in video peak signal-to-noise ratio, compared with the classical single-layer scheme using conventional modulation. PMID:24808347

  14. Collaborative-Comparison Learning for Complex Event Detection Using Distributed Hierarchical Graph Neuron (DHGN) Approach in Wireless Sensor Network

    NASA Astrophysics Data System (ADS)

    Muhamad Amin, Anang Hudaya; Khan, Asad I.

    Research trends in existing event detection schemes using Wireless Sensor Network (WSN) have mainly focused on routing and localisation of nodes for optimum coordination when retrieving sensory information. Efforts have also been put in place to create schemes that are able to provide learning mechanisms for event detection using classification or clustering approaches. These schemes entail substantial communication and computational overheads owing to the event-oblivious nature of data transmissions. In this paper, we present an event detection scheme that has the ability to distribute detection processes over the resource-constrained wireless sensor nodes and is suitable for events with spatio-temporal characteristics. We adopt a pattern recognition algorithm known as Distributed Hierarchical Graph Neuron (DHGN) with collaborative-comparison learning for detecting critical events in WSN. The scheme demonstrates good accuracy for binary classification and offers low-complexity and high-scalability in terms of its processing requirements.

  15. Prolonging the lifetime of wireless sensor networks interconnected to fixed network using hierarchical energy tree based routing algorithm.

    PubMed

    Kalpana, M; Dhanalakshmi, R; Parthiban, P

    2014-01-01

    This research work proposes a mathematical model for the lifetime of wireless sensor networks (WSN). It also proposes an energy efficient routing algorithm for WSN called hierarchical energy tree based routing algorithm (HETRA) based on hierarchical energy tree constructed using the available energy in each node. The energy efficiency is further augmented by reducing the packet drops using exponential congestion control algorithm (TCP/EXP). The algorithms are evaluated in WSNs interconnected to fixed network with seven distribution patterns, simulated in ns2 and compared with the existing algorithms based on the parameters such as number of data packets, throughput, network lifetime, and data packets average network lifetime product. Evaluation and simulation results show that the combination of HETRA and TCP/EXP maximizes longer network lifetime in all the patterns. The lifetime of the network with HETRA algorithm has increased approximately 3.2 times that of the network implemented with AODV. PMID:25535626

  16. Prolonging the Lifetime of Wireless Sensor Networks Interconnected to Fixed Network Using Hierarchical Energy Tree Based Routing Algorithm

    PubMed Central

    Kalpana, M.; Dhanalakshmi, R.; Parthiban, P.

    2014-01-01

    This research work proposes a mathematical model for the lifetime of wireless sensor networks (WSN). It also proposes an energy efficient routing algorithm for WSN called hierarchical energy tree based routing algorithm (HETRA) based on hierarchical energy tree constructed using the available energy in each node. The energy efficiency is further augmented by reducing the packet drops using exponential congestion control algorithm (TCP/EXP). The algorithms are evaluated in WSNs interconnected to fixed network with seven distribution patterns, simulated in ns2 and compared with the existing algorithms based on the parameters such as number of data packets, throughput, network lifetime, and data packets average network lifetime product. Evaluation and simulation results show that the combination of HETRA and TCP/EXP maximizes longer network lifetime in all the patterns. The lifetime of the network with HETRA algorithm has increased approximately 3.2 times that of the network implemented with AODV. PMID:25535626

  17. Bidirectional QoS support for novelty detection applications based on hierarchical wireless sensor network model

    NASA Astrophysics Data System (ADS)

    Edwards, Mark; Hu, Fei; Kumar, Sunil

    2004-10-01

    The research on the Novelty Detection System (NDS) (called as VENUS) at the authors' universities has generated exciting results. For example, we can detect an abnormal behavior (such as cars thefts from the parking lot) from a series of video frames based on the cognitively motivated theory of habituation. In this paper, we would like to describe the implementation strategies of lower layer protocols for using large-scale Wireless Sensor Networks (WSN) to NDS with Quality-of-Service (QoS) support. Wireless data collection framework, consisting of small and low-power sensor nodes, provides an alternative mechanism to observe the physical world, by using various types of sensing capabilities that include images (and even videos using Panoptos), sound and basic physical measurements such as temperature. We do not want to lose any 'data query command' packets (in the downstream direction: sink-to-sensors) or have any bit-errors in them since they are so important to the whole sensor network. In the upstream direction (sensors-to-sink), we may tolerate the loss of some sensing data packets. But the 'interested' sensing flow should be assigned a higher priority in terms of multi-hop path choice, network bandwidth allocation, and sensing data packet generation frequency (we hope to generate more sensing data packet for that novel event in the specified network area). The focus of this paper is to investigate MAC-level Quality of Service (QoS) issue in Wireless Sensor Networks (WSN) for Novelty Detection applications. Although QoS has been widely studied in other types of networks including wired Internet, general ad hoc networks and mobile cellular networks, we argue that QoS in WSN has its own characteristics. In wired Internet, the main QoS parameters include delay, jitter and bandwidth. In mobile cellular networks, two most common QoS metrics are: handoff call dropping probability and new call blocking probability. Since the main task of WSN is to detect and report

  18. Enhanced Deployment Strategy for Role-based Hierarchical Application Agents in Wireless Sensor Networks with Established Clusterheads

    NASA Astrophysics Data System (ADS)

    Gendreau, Audrey

    Efficient self-organizing virtual clusterheads that supervise data collection based on their wireless connectivity, risk, and overhead costs, are an important element of Wireless Sensor Networks (WSNs). This function is especially critical during deployment when system resources are allocated to a subsequent application. In the presented research, a model used to deploy intrusion detection capability on a Local Area Network (LAN), in the literature, was extended to develop a role-based hierarchical agent deployment algorithm for a WSN. The resulting model took into consideration the monitoring capability, risk, deployment distribution cost, and monitoring cost associated with each node. Changing the original LAN methodology approach to model a cluster-based sensor network depended on the ability to duplicate a specific parameter that represented the monitoring capability. Furthermore, other parameters derived from a LAN can elevate costs and risk of deployment, as well as jeopardize the success of an application on a WSN. A key component of the approach presented in this research was to reduce the costs when established clusterheads in the network were found to be capable of hosting additional detection agents. In addition, another cost savings component of the study addressed the reduction of vulnerabilities associated with deployment of agents to high volume nodes. The effectiveness of the presented method was validated by comparing it against a type of a power-based scheme that used each node's remaining energy as the deployment value. While available energy is directly related to the model used in the presented method, the study deliberately sought out nodes that were identified with having superior monitoring capability, cost less to create and sustain, and are at low-risk of an attack. This work investigated improving the efficiency of an intrusion detection system (IDS) by using the proposed model to deploy monitoring agents after a temperature sensing

  19. Enhanced Deployment Strategy for Role-Based Hierarchical Application Agents in Wireless Sensor Networks with Established Clusterheads

    ERIC Educational Resources Information Center

    Gendreau, Audrey

    2014-01-01

    Efficient self-organizing virtual clusterheads that supervise data collection based on their wireless connectivity, risk, and overhead costs, are an important element of Wireless Sensor Networks (WSNs). This function is especially critical during deployment when system resources are allocated to a subsequent application. In the presented research,…

  20. Nikola Tesla: the man behind the magnetic field unit.

    PubMed

    Roguin, Ariel

    2004-03-01

    The magnetic field strength of both the magnet and gradient coils used in MR imaging equipment is measured in Tesla units, which are named for Nikola Tesla. This article presents the life and achievements of this Serbian-American inventor and researcher who discovered the rotating magnetic field, the basis of most alternating-current machinery. Nikola Tesla had 700 patents in the United States and Europe that covered every aspect of science and technology. Tesla's discoveries include the Tesla coil, AC electrical conduction, improved lighting, newer forms of turbine engines, robotics, fluorescent light, wireless transmission of electrical energy, radio, remote control, discovery of cosmic radio waves, and the use of the ionosphere for scientific purposes. He was a genius whose discoveries had a pivotal role in advancing us into the modern era. PMID:14994307

  1. The TESLA RF System

    NASA Astrophysics Data System (ADS)

    Choroba, S.

    2003-12-01

    The TESLA project proposed by the TESLA collaboration in 2001 is a 500 to 800GeV e+/e- linear collider with integrated free electron laser facility. The accelerator is based on superconducting cavity technology. Approximately 20000 superconducting cavities operated at 1.3GHz with a gradient of 23.4MV/m or 35MV/m will be required to achieve the energy of 500GeV or 800GeV respectively. For 500GeV ˜600 RF stations each generating 10MW of RF power at 1.3GHz at a pulse duration of 1.37ms and a repetition rate of 5 or 10Hz are required. The original TESLA design was modified in 2002 and now includes a dedicated 20GeV electron accelerator in a separate tunnel for free electron laser application. The TESLA XFEL will provide XFEL radiation of unprecedented peak brilliance and full transverse coherence in the wavelength range of 0.1 to 6.4nm at a pulse duration of 100fs. The technology of both accelerators, the TESLA linear collider and the XFEL, will be identical, however the number of superconducting cavities and RF stations for the XFEL will be reduced to 936 and 26 respectively. This paper describes the layout of the entire RF system of the TESLA linear collider and the TESLA XFEL and gives an overview of its various subsystems and components.

  2. Photon collider at TESLA

    NASA Astrophysics Data System (ADS)

    Telnov, Valery

    2001-10-01

    High energy photon colliders ( γγ, γe) based on backward Compton scattering of laser light is a very natural addition to e +e - linear colliders. In this report, we consider this option for the TESLA project. Recent study has shown that the horizontal emittance in the TESLA damping ring can be further decreased by a factor of four. In this case, the γγ luminosity in the high energy part of spectrum can reach about (1/3) Le +e -. Typical cross-sections of interesting processes in γγ collisions are higher than those in e +e - collisions by about one order of magnitude, so the number of events in γγ collisions will be more than that in e +e - collisions. Photon colliders can, certainly, give additional information and they are the best for the study of many phenomena. The main question is now the technical feasibility. The key new element in photon colliders is a very powerful laser system. An external optical cavity is a promising approach for the TESLA project. A free electron laser is another option. However, a more straightforward solution is "an optical storage ring (optical trap)" with a diode pumped solid state laser injector which is today technically feasible. This paper briefly reviews the status of a photon collider based on the linear collider TESLA, its possible parameters and existing problems.

  3. Note: Tesla transformer damping

    NASA Astrophysics Data System (ADS)

    Reed, J. L.

    2012-07-01

    Unexpected heavy damping in the two winding Tesla pulse transformer is shown to be due to small primary inductances. A small primary inductance is a necessary condition of operability, but is also a refractory inefficiency. A 30% performance loss is demonstrated using a typical "spiral strip" transformer. The loss is investigated by examining damping terms added to the transformer's governing equations. A significant alteration of the transformer's architecture is suggested to mitigate these losses. Experimental and simulated data comparing the 2 and 3 winding transformers are cited to support the suggestion.

  4. TESLA & ILC Cryomodules

    SciTech Connect

    Peterson, T. J.; Weisend, II, J. G.

    2016-01-01

    The TESLA collaboration developed a unique variant of SRF cryomodule designs, the chief feature being use of the large, low pressure helium vapor return pipe as the structural support backbone of the cryomodule. Additional innovative features include all cryogenic piping within the cryomodule (no parallel external cryogenic transfer line), long strings of RF cavities within a single cryomodule, and cryomodules connected in series. Several projects, including FLASH and XFEL at DESY, LCLS-II at SLAC, and the ILC technical design have adopted this general design concept. Advantages include saving space by eliminating the external transfer line, relatively tight packing of RF cavities along the beamline due to fewer warm-cold transitions, and potentially lower costs. However, a primary disadvantage is the relative lack of independence for warm-up, replacement, and cool-down of individual cryomodules.

  5. [70 years of Nikola Tesla studies].

    PubMed

    Juznic, Stanislav

    2013-01-01

    Nikola Tesla's studies of chemistry are described including his not very scholarly affair in Maribor. After almost a century and half of hypothesis at least usable scenario of Tesla's life and "work" in Maribor is provided. The chemistry achievements of Tesla's most influential professors Martin Sekulić and Tesla's Graz professors are put into the limelight. The fact that Tesla in Graz studied on the technological chemistry Faculty of Polytechnic is focused. PMID:23878954

  6. Nikola Tesla: the Moon's rotation.

    NASA Astrophysics Data System (ADS)

    Tomić, A.; Jovanović, B. S.

    1993-09-01

    The review of three articles by N. Tesla, published in the year 1919 in the journal "Electrical experimenter" is given, with special reference to the astronomical contents and to circumstances in which they appeared.

  7. [Nikola Tesla in medicine, too].

    PubMed

    Hanzek, Branko; Jakobović, Zvonimir

    2007-12-01

    Using primary and secondary sources we have shown in this paper the influence of Nikola Tesla's work on the field of medicine. The description of his experiments conduced within secondary-school education programs aimed to present the popularization of his work in Croatia. Although Tesla was dedicated primarily to physics and was not directly involved in biomedical research, his work significantly contributed to paving the way of medical physics particularly radiology and high-frequency electrotherapy. PMID:18383745

  8. The Photon Collider at Tesla

    NASA Astrophysics Data System (ADS)

    Badelek, B.; Blöchinger, C.; Blümlein, J.; Boos, E.; Brinkmann, R.; Burkhardt, H.; Bussey, P.; Carimalo, C.; Chyla, J.; Çiftçi, A. K.; Decking, W.; de Roeck, A.; Fadin, V.; Ferrario, M.; Finch, A.; Fraas, H.; Franke, F.; Galynskii, M.; Gamp, A.; Ginzburg, I.; Godbole, R.; Gorbunov, D. S.; Gounaris, G.; Hagiwara, K.; Han, L.; Heuer, R.-D.; Heusch, C.; Illana, J.; Ilyin, V.; Jankowski, P.; Jiang, Y.; Jikia, G.; Jönsson, L.; Kalachnikow, M.; Kapusta, F.; Klanner, R.; Klassen, M.; Kobayashi, K.; Kon, T.; Kotkin, G.; Krämer, M.; Krawczyk, M.; Kuang, Y. P.; Kuraev, E.; Kwiecinski, J.; Leenen, M.; Levchuk, M.; Ma, W. F.; Martyn, H.; Mayer, T.; Melles, M.; Miller, D. J.; Mtingwa, S.; Mühlleitner, M.; Muryn, B.; Nickles, P. V.; Orava, R.; Pancheri, G.; Penin, A.; Potylitsyn, A.; Poulose, P.; Quast, T.; Raimondi, P.; Redlin, H.; Richard, F.; Rindani, S. D.; Rizzo, T.; Saldin, E.; Sandner, W.; Schönnagel, H.; Schneidmiller, E.; Schreiber, H. J.; Schreiber, S.; Schüler, K. P.; Serbo, V.; Seryi, A.; Shanidze, R.; da Silva, W.; Söldner-Rembold, S.; Spira, M.; Stasto, A. M.; Sultansoy, S.; Takahashi, T.; Telnov, V.; Tkabladze, A.; Trines, D.; Undrus, A.; Wagner, A.; Walker, N.; Watanabe, I.; Wengler, T.; Will, I.; Wipf, S.; Yavaş, Ö.; Yokoya, K.; Yurkov, M.; Zarnecki, A. F.; Zerwas, P.; Zomer, F.

    High energy photon colliders (γγ,γe) are based on e-e- linear colliders where high energy photons are produced using Compton scattering of laser light on high energy electrons just before the interaction point. This paper is a part of the Technical Design Report of the linear collider TESLA.1 Physics program, possible parameters and some technical aspects of the photon collider at TESLA are discussed.

  9. The TESLA Free Electron Laser

    NASA Astrophysics Data System (ADS)

    Rossbach, Jörg

    1997-05-01

    The TESLA Free Electron Laser makes use of the high quality electron beam that can be provided by the superconducting TESLA linac to drive a single pass free electron laser (FEL) at wavelengths far below the visible. To reach a wavelength of 6 nanometers, the TESLA Test Facility (TTF) currently under construction at DESY will be extended to 1 GeV beam energy. Because there are no mirrors and seed-lasers in this wavelength regime, the principle of Self-Amplified-Spontaneous-Emission (SASE) will be employed. A first test of both the principle and technical components is foreseen at a photon wavelength larger than 42 nanometers. With respect to linac technology, the key prerequisite for such single-pass, high-gain FELs is a high intensity, diffraction limited, electron beam to be generated and accelerated without degradation. Key components are RF guns with photocathodes, bunch compressors, and related diagnostics. The status of design and construction as well as both electron and photon beam properties will be discussed. Once proven in the micrometer to nanometer regime, the SASE FEL scheme is considered applicable down to Angstrom wavelengths. It is pointed out that this latter option is particularly of interest in context with the construction of a linear collider, which requires very similar beam parameters. The status of conceptual design work on such a coherent X-ray user facility integrated into the TESLA linear collider design will be briefly sketched.

  10. Nikola Tesla Educational Opportunity School.

    ERIC Educational Resources Information Center

    Design Cost Data, 2001

    2001-01-01

    Describes the architectural design, costs, general description, and square footage data for the Nikola Tesla Educational Opportunity School in Colorado Springs, Colorado. A floor plan and photos are included along with a list of manufacturers and suppliers used for the project. (GR)

  11. Hierarchical scheme for detecting the rotating MIMO transmission of the in-door RGB-LED visible light wireless communications using mobile-phone camera

    NASA Astrophysics Data System (ADS)

    Chen, Shih-Hao; Chow, Chi-Wai

    2015-01-01

    Multiple-input and multiple-output (MIMO) scheme can extend the transmission capacity for the light-emitting-diode (LED) based visible light communication (VLC) systems. The MIMO VLC system that uses the mobile-phone camera as the optical receiver (Rx) to receive MIMO signal from the n×n Red-Green-Blue (RGB) LED array is desirable. The key step of decoding this signal is to detect the signal direction. If the LED transmitter (Tx) is rotated, the Rx may not realize the rotation and transmission error can occur. In this work, we propose and demonstrate a novel hierarchical transmission scheme which can reduce the computation complexity of rotation detection in LED array VLC system. We use the n×n RGB LED array as the MIMO Tx. In our study, a novel two dimensional Hadamard coding scheme is proposed. Using the different LED color layers to indicate the rotation, a low complexity rotation detection method can be used for improving the quality of received signal. The detection correction rate is above 95% in the indoor usage distance. Experimental results confirm the feasibility of the proposed scheme.

  12. Tesla - A Flash of a Genius

    NASA Astrophysics Data System (ADS)

    Teodorani, M.

    2005-10-01

    This book, which is entirely dedicated to the inventions of scientist Nikola Tesla, is divided into three parts: a) all the most important innovative technological creations from the alternate current to the death ray, Tesla research in fundamental physics with a particular attention to the concept of "ether", ball lightning physics; b) the life and the bright mind of Nikola Tesla and the reasons why some of his most recent findings were not accepted by the establishment; c) a critical discussion of the most important work by Tesla followers.

  13. Hierarchical photocatalysts.

    PubMed

    Li, Xin; Yu, Jiaguo; Jaroniec, Mietek

    2016-05-01

    As a green and sustainable technology, semiconductor-based heterogeneous photocatalysis has received much attention in the last few decades because it has potential to solve both energy and environmental problems. To achieve efficient photocatalysts, various hierarchical semiconductors have been designed and fabricated at the micro/nanometer scale in recent years. This review presents a critical appraisal of fabrication methods, growth mechanisms and applications of advanced hierarchical photocatalysts. Especially, the different synthesis strategies such as two-step templating, in situ template-sacrificial dissolution, self-templating method, in situ template-free assembly, chemically induced self-transformation and post-synthesis treatment are highlighted. Finally, some important applications including photocatalytic degradation of pollutants, photocatalytic H2 production and photocatalytic CO2 reduction are reviewed. A thorough assessment of the progress made in photocatalysis may open new opportunities in designing highly effective hierarchical photocatalysts for advanced applications ranging from thermal catalysis, separation and purification processes to solar cells. PMID:26963902

  14. [Nikola Tesla: flashes of inspiration].

    PubMed

    Villarejo-Galende, Albero; Herrero-San Martín, Alejandro

    2013-01-16

    Nikola Tesla (1856-1943) was one of the greatest inventors in history and a key player in the revolution that led to the large-scale use of electricity. He also made important contributions to such diverse fields as x-rays, remote control, radio, the theory of consciousness or electromagnetism. In his honour, the international unit of magnetic induction was named after him. Yet, his fame is scarce in comparison with that of other inventors of the time, such as Edison, with whom he had several heated arguments. He was a rather odd, reserved person who lived for his inventions, the ideas for which came to him in moments of inspiration. In his autobiography he relates these flashes with a number of neuropsychiatric manifestations, which can be seen to include migraine auras, synaesthesiae, obsessions and compulsions. PMID:23307357

  15. Electron-electron collisions at TESLA

    NASA Astrophysics Data System (ADS)

    Schreiber, Siegfried; Reyzl, Ingrid

    2001-07-01

    Electron-electron collisions at the future TESLA linear collider is a promising complement to e+e- collisions. A critical issue for the physics potential of this option is the achievable luminosity. For e+e- collisions, the pinch effect enhances the luminosity, while due to the repelling forces for e-e- collisions, the luminosity is significantly reduced and is more sensitive to beam separations. This report discusses the e-e- option for TESLA and the expected luminosity.

  16. Conduction-coupled Tesla transformer

    NASA Astrophysics Data System (ADS)

    Reed, J. L.

    2015-03-01

    A proof-of-principle Tesla transformer circuit is introduced. The new transformer exhibits the high voltage-high power output signal of shock-excited transformers. The circuit, with specification of proper circuit element values, is capable of obtaining extreme oscillatory voltages. The primary and secondary portions of the circuit communicate solely by conduction. The destructive arcing between the primary and secondary inductors in electromagnetically coupled transformers is ubiquitous. Flashover is eliminated in the new transformer as the high-voltage inductors do not interpenetrate and so do not possess an annular volume of electric field. The inductors are remote from one another. The high voltage secondary inductor is isolated in space, except for a base feed conductor, and obtains earth by its self-capacitance to the surroundings. Governing equations, for the ideal case of no damping, are developed from first principles. Experimental, theoretical, and circuit simulator data are presented for the new transformer. Commercial high-temperature superconductors are discussed as a means to eliminate the counter-intuitive damping due to small primary inductances in both the electromagnetic-coupled and new conduction-coupled transformers.

  17. Conduction-coupled Tesla transformer.

    PubMed

    Reed, J L

    2015-03-01

    A proof-of-principle Tesla transformer circuit is introduced. The new transformer exhibits the high voltage-high power output signal of shock-excited transformers. The circuit, with specification of proper circuit element values, is capable of obtaining extreme oscillatory voltages. The primary and secondary portions of the circuit communicate solely by conduction. The destructive arcing between the primary and secondary inductors in electromagnetically coupled transformers is ubiquitous. Flashover is eliminated in the new transformer as the high-voltage inductors do not interpenetrate and so do not possess an annular volume of electric field. The inductors are remote from one another. The high voltage secondary inductor is isolated in space, except for a base feed conductor, and obtains earth by its self-capacitance to the surroundings. Governing equations, for the ideal case of no damping, are developed from first principles. Experimental, theoretical, and circuit simulator data are presented for the new transformer. Commercial high-temperature superconductors are discussed as a means to eliminate the counter-intuitive damping due to small primary inductances in both the electromagnetic-coupled and new conduction-coupled transformers. PMID:25832281

  18. Science up to 100 tesla

    SciTech Connect

    Campbell, L.J.

    1995-05-01

    100 Tesla is the highest attainable field that can be held for milli-sec in a non-destructive magnet. The strongest steels turn soft under stresses of 4GPa, which is the magnetic pressure of 100 T. Until there is a breakthrough in materials, magnets having all the low temperature and high pressure trimmings will be limited to about 100 T. Within the field range 1-100 T far more resources are now devoted to producing the highest possible continuous fields (40+5 T) than to producing longer pulsed fields above 50 T. This illustrates that the utility of the field can be more important than the strength of the field to researchers in condensed matter. Discoveries are typically made in new territory, but this can be new combinations of pressure, temperature, and magnetic field, or new probes and new materials. If any activity has kept up with the proliferation of new experiments and new facilities in high magnetic field research it is the listing of experiments that could and should be done in high fields. Part of the reason for the vitality of high field research is that high fields provide a generic environment. Compared to particle accelerators and plasma machines a high field laboratory is a setting for generic science, like synchrotron light sources or neutron scattering centers. Although the latter two installations probes states, while a magnetic field creates a state. Because it is unrealistic to try to list all the science opportunities at high fields, the author list sources for lists in the public domain and gives a few examples.

  19. Thirteen Tesla magnet constructed with MJR wire

    SciTech Connect

    Siddall, M.; Efferson, K.; Mcdonald, W.

    1983-05-01

    The authors have constructed an insert booster superconducting magnet of 20 mm clear bore and outside diameter of 100 mm and height 130 mm, wound and reacted from the Teledyne patented foraminous layered foil (jelly roll) wire fabricated by low cost, non-rebundled reduction to wire. This magnet was placed inside the 101 mm bore of a NbTi wound solenoid which was operated at 8.5 Tesla. The total field achieved was 13.0 Tesla with no training quench observed; although training was initially observed when the magnet was first tested alone up to 4.6 Tesla at American Magnets, Inc. (AMI). The magnet winding techniques utilize Airco's fiberglass type wire insulation, an AMI proprietary cement, argon atmosphere 700/sup 0/C for 100 hour reaction, followed by a postreaction potting impregnation. The MJR wire lot used (M22) was short sample tested and the Ln (J /SUB c/ ) -vs-H line intersected the insert magnet operating curve at 13.5 Tesla. The wire lot used has a 34 volume % copper external sheath for quench protection. The wire was fabricated with 15.4 volume % niobium and bronze/niobium ratio of 3.0 with 13.% Sn bronze.

  20. Nikola Tesla, the Ether and his Telautomaton

    NASA Astrophysics Data System (ADS)

    Milar, Kendall

    2014-03-01

    In the nineteenth century physicists' understanding of the ether changed dramatically. New developments in thermodynamics, energy physics, and electricity and magnetism dictated new properties of the ether. These have traditionally been examined from the perspective of the scientists re-conceptualizing the ether. However Nikola Tesla, a prolific inventor and writer, presents a different picture of nineteenth century physics. Alongside the displays that showcased his inventions he presented alternative interpretations of physical, physiological and even psychical research. This is particularly evident in his telautomaton, a radio remote controlled boat. This invention and Tesla's descriptions of it showcase some of his novel interpretations of physical theories. He offered a perspective on nineteenth century physics that focused on practical application instead of experiment. Sometimes the understanding of physical theories that Tesla reached was counterproductive to his own inventive work; other times he offered new insights. Tesla's utilitarian interpretation of physical theories suggests a more scientifically curious and invested inventor than previously described and a connection between the scientific and inventive communities.

  1. Wireless Andrew.

    ERIC Educational Resources Information Center

    Fickes, Michael

    2000-01-01

    Describes the use of the Internet and laptops help Carnegie Mellon University students carry out sophisticated research anywhere on campus. How the university became a wireless community is discussed. (GR)

  2. MIT 12 Tesla Coil test results

    NASA Astrophysics Data System (ADS)

    Steeves, M. M.; Hoenig, M. O.

    1985-07-01

    Test results from the MIT 12 Tesla Coil experiment are presented. The coil was tested in the High Field Test Facility (HFTF) of the Lawrence Livermore National Laboratory in October 1984 and January 1985. The experiment measured the performance of an Internally Cooled, Cabled Superconductor (ICCS) of practical size, intended for use in magnetic fusion experiments. The MIT coil carried 15 kA at 11 T for 5 min with no sign of instability. A half turn length in a 10 T field was able to absorb a heat load in 4 msec of more than 200 mJ sub cm of cable volume while carrying a current of 12 kA. The MIT coil successfully met the performance requirements of the Department of Energy's 12 Tesla Coil Program.

  3. Design and scaling of microscale Tesla turbines

    NASA Astrophysics Data System (ADS)

    Krishnan, Vedavalli G.; Romanin, Vince; Carey, Van P.; Maharbiz, Michel M.

    2013-12-01

    We report on the scaling properties and loss mechanisms of Tesla turbines and provide design recommendations for scaling such turbines to the millimeter scale. Specifically, we provide design, fabrication and experimental data for a low-pressure head hydro Tesla micro-turbine. We derive the analytical turbine performance for incompressible flow and then develop a more detailed model that predicts experimental performance by including a variety of loss mechanisms. We report the correlation between them and the experimental results. Turbines with 1 cm rotors, 36% peak efficiency (at 2 cm3 s-1 flow) and 45 mW unloaded peak power (at 12 cm3 s-1 flow) are demonstrated. We analyze the causes for head loss and shaft power loss and derive constraints on turbine design. We then analyze the effect of scaling down on turbine efficiency, power density and rotor revolutions/min. Based on the analysis, we make recommendations for the design of ˜1 mm microscale Tesla turbines.

  4. Wireless Communications

    NASA Technical Reports Server (NTRS)

    1991-01-01

    A technology utilization project led to the commercial adaptation of a Space Shuttle Orbiter wireless infrared voice communications system. The technology was adapted to a LAN system by Wilton Industries, one of the participants. Because the system is cable-free, installation charges are saved, and it can be used where cable is impractical. Resultant products include the IRplex 6000. Transceivers can be located anywhere and can include mobile receivers. The system provides wireless LAN coverage up to 44,000 square feet. applications include stock exchange communications, trade shows, emergency communications, etc.

  5. Bayesian Hierarchical Classes Analysis

    ERIC Educational Resources Information Center

    Leenen, Iwin; Van Mechelen, Iven; Gelman, Andrew; De Knop, Stijn

    2008-01-01

    Hierarchical classes models are models for "N"-way "N"-mode data that represent the association among the "N" modes and simultaneously yield, for each mode, a hierarchical classification of its elements. In this paper we present a stochastic extension of the hierarchical classes model for two-way two-mode binary data. In line with the original…

  6. Wireless Technician

    ERIC Educational Resources Information Center

    Tech Directions, 2011

    2011-01-01

    One of the hottest areas in technology is invisible. Wireless communications allow people to transmit voice messages, data, and other signals through the air without physically connecting senders to receivers with cables or wires. And the technology is spreading at lightning speed. Cellular phones, personal digital assistants, and wireless…

  7. Wireless Protection.

    ERIC Educational Resources Information Center

    Conforti, Fred

    2003-01-01

    Discusses wireless access-control equipment in the school and university setting, particularly the integrated reader lock at the door with a panel interface module at the control panel. Describes its benefits, how it works, and its reliability and security. (EV)

  8. Building new access network using reconfigurable optical grid network and wireless network

    NASA Astrophysics Data System (ADS)

    Qiu, Yinghui; Wu, Runze; Ji, Yuefeng; Xu, Daxiong

    2007-11-01

    Recently wireless mesh network has been gaining increasing attention and early versions are being deployed as municipal access solutions to eliminate the wired drop to every wireless router at customer premise. In this paper, we propose a novel access network using reconfigurable optical burst switching grid network and wireless mesh network. The proposed access network architecture saves network deployment cost because fiber need not penetrate to each end user. We also propose a hierarchical routing protocol to enhance the routing efficiency.

  9. Jakob Narkiewicz-Jodko-Tesla ``Predecessor''

    NASA Astrophysics Data System (ADS)

    Samuilov, Vladimir; Kiselev, Vladimir

    2014-03-01

    Prof. Jakob Narkiewicz-Jodko (1947-1905) is a bright figure in the history of science of the XIXth century. His major discoveries are: Electrography - the method of the visualization of electric discharge from the bodies due to the application of high strength and high frequency electric fields, and one of the first observations of the propagation of the electromagnetic waives and information transfer over the distances. We review Prof. Jakob Narkiewicz-Jodko's research results and explain our point why we consider him as the predecessor of Nikola Tesla.

  10. Connected Dominating Set Based Topology Control in Wireless Sensor Networks

    ERIC Educational Resources Information Center

    He, Jing

    2012-01-01

    Wireless Sensor Networks (WSNs) are now widely used for monitoring and controlling of systems where human intervention is not desirable or possible. Connected Dominating Sets (CDSs) based topology control in WSNs is one kind of hierarchical method to ensure sufficient coverage while reducing redundant connections in a relatively crowded network.…

  11. Theory and Performance of Tesla Turbines

    NASA Astrophysics Data System (ADS)

    Romanin, Vincent Domenic

    This document summarizes the development of an integral perturbation solution of the equations governing momentum transport in microchannels between disks of multiple-disk drag turbines such as the Tesla turbine. This analysis allows a parametric study of turbine performance based on several nondimensional parameters. The results of this analysis are then compared to two sets of test data published in previous work and by other projects. The results are further compared to Computational Fluid Dynamics (CFD) simulations. Finally, expected performance and potential applications of these devices are discussed in light of the results developed. Analysis of this type of flow problem is a key element in the optimal design of Tesla drag-type turbines for geothermal, waste heat, energy harvesting, or solar alternative energy applications. In multiple-disk turbines, high speed flow enters tangentially at the outer radius of cylindrical microchannels formed by closely spaced parallel disks, spiraling through the channel to an exhaust at a small radius or at the center of the disk. Previous investigations have generally developed models based on simplifying idealizations of the flow in these circumstances. Here, beginning with the momentum and continuity equations for incompressible and steady flow in cylindrical coordinates, an integral solution scheme is developed that leads to a dimensionless perturbation series solution that retains the full complement of momentum and viscous effects to consistent levels of approximation in the series solution. This more rigorous approach indicates all dimensionless parameters that affect flow and transport, and allows a direct assessment of the relative importance of viscous, pressure, and momentum effects in different directions in the flow. The resulting lowest-order equations are solved explicitly and higher order terms in the series solutions are determined numerically. Enhancement of rotor drag in this type of turbine enhances

  12. 77 FR 22383 - Petition for Exemption From the Federal Motor Vehicle Motor Theft Prevention Standard; TESLA

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-13

    ... Theft Prevention Standard; TESLA AGENCY: National Highway Traffic Safety Administration (NHTSA... full the petition of Tesla Motors Inc's. (Tesla) for an exemption of the Model S vehicle line in... Prevention Standard. Tesla requested confidential treatment for specific information in its petition....

  13. 76 FR 47639 - Tesla Motors, Inc.; Receipt of Petition for Temporary Exemption From the Electronic Stability...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-05

    ... National Highway Traffic Safety Administration Tesla Motors, Inc.; Receipt of Petition for Temporary... Stability Control Systems. SUMMARY: In accordance with the procedures in 49 CFR part 555, Tesla Motors, Inc... accordance with 49 U.S.C. 30113 and the procedures in 49 CFR part 555, Tesla Motors, Inc. (Tesla) submitted...

  14. Hierarchical Models of Attitude.

    ERIC Educational Resources Information Center

    Reddy, Srinivas K.; LaBarbera, Priscilla A.

    1985-01-01

    The application and use of hierarchical models is illustrated, using the example of the structure of attitudes toward a new product and a print advertisement. Subjects were college students who responded to seven-point bipolar scales. Hierarchical models were better than nonhierarchical models in conceptualizing attitude but not intention. (GDC)

  15. Hierarchical quantum communication

    NASA Astrophysics Data System (ADS)

    Shukla, Chitra; Pathak, Anirban

    2013-08-01

    A general approach to study the hierarchical quantum information splitting (HQIS) is proposed and the same is used to systematically investigate the possibility of realizing HQIS using different classes of 4-qubit entangled states that are not connected by stochastic local operations and classical communication (SLOCC). Explicit examples of HQIS using 4-qubit cluster state and 4-qubit |Ω> state are provided. Further, the proposed HQIS scheme is generalized to introduce two new aspects of hierarchical quantum communication. To be precise, schemes of probabilistic hierarchical quantum information splitting and hierarchical quantum secret sharing are obtained by modifying the proposed HQIS scheme. A number of practical situations where hierarchical quantum communication would be of use, are also presented.

  16. A wireless sensor enabled by wireless power.

    PubMed

    Lee, Da-Sheng; Liu, Yu-Hong; Lin, Chii-Ruey

    2012-01-01

    Through harvesting energy by wireless charging and delivering data by wireless communication, this study proposes the concept of a wireless sensor enabled by wireless power (WPWS) and reports the fabrication of a prototype for functional tests. One WPWS node consists of wireless power module and sensor module with different chip-type sensors. Its main feature is the dual antenna structure. Following RFID system architecture, a power harvesting antenna was designed to gather power from a standard reader working in the 915 MHz band. Referring to the Modbus protocol, the other wireless communication antenna was integrated on a node to send sensor data in parallel. The dual antenna structure integrates both the advantages of an RFID system and a wireless sensor. Using a standard UHF RFID reader, WPWS can be enabled in a distributed area with a diameter up to 4 m. Working status is similar to that of a passive tag, except that a tag can only be queried statically, while the WPWS can send dynamic data from the sensors. The function is the same as a wireless sensor node. Different WPWSs equipped with temperature and humidity, optical and airflow velocity sensors are tested in this study. All sensors can send back detection data within 8 s. The accuracy is within 8% deviation compared with laboratory equipment. A wireless sensor network enabled by wireless power should be a totally wireless sensor network using WPWS. However, distributed WPWSs only can form a star topology, the simplest topology for constructing a sensor network. Because of shielding effects, it is difficult to apply other complex topologies. Despite this limitation, WPWS still can be used to extend sensor network applications in hazardous environments. Further research is needed to improve WPWS to realize a totally wireless sensor network. PMID:23443370

  17. A Wireless Sensor Enabled by Wireless Power

    PubMed Central

    Lee, Da-Sheng; Liu, Yu-Hong; Lin, Chii-Ruey

    2012-01-01

    Through harvesting energy by wireless charging and delivering data by wireless communication, this study proposes the concept of a wireless sensor enabled by wireless power (WPWS) and reports the fabrication of a prototype for functional tests. One WPWS node consists of wireless power module and sensor module with different chip-type sensors. Its main feature is the dual antenna structure. Following RFID system architecture, a power harvesting antenna was designed to gather power from a standard reader working in the 915 MHz band. Referring to the Modbus protocol, the other wireless communication antenna was integrated on a node to send sensor data in parallel. The dual antenna structure integrates both the advantages of an RFID system and a wireless sensor. Using a standard UHF RFID reader, WPWS can be enabled in a distributed area with a diameter up to 4 m. Working status is similar to that of a passive tag, except that a tag can only be queried statically, while the WPWS can send dynamic data from the sensors. The function is the same as a wireless sensor node. Different WPWSs equipped with temperature and humidity, optical and airflow velocity sensors are tested in this study. All sensors can send back detection data within 8 s. The accuracy is within 8% deviation compared with laboratory equipment. A wireless sensor network enabled by wireless power should be a totally wireless sensor network using WPWS. However, distributed WPWSs only can form a star topology, the simplest topology for constructing a sensor network. Because of shielding effects, it is difficult to apply other complex topologies. Despite this limitation, WPWS still can be used to extend sensor network applications in hazardous environments. Further research is needed to improve WPWS to realize a totally wireless sensor network. PMID:23443370

  18. Hierarchical Auxetic Mechanical Metamaterials

    PubMed Central

    Gatt, Ruben; Mizzi, Luke; Azzopardi, Joseph I.; Azzopardi, Keith M.; Attard, Daphne; Casha, Aaron; Briffa, Joseph; Grima, Joseph N.

    2015-01-01

    Auxetic mechanical metamaterials are engineered systems that exhibit the unusual macroscopic property of a negative Poisson's ratio due to sub-unit structure rather than chemical composition. Although their unique behaviour makes them superior to conventional materials in many practical applications, they are limited in availability. Here, we propose a new class of hierarchical auxetics based on the rotating rigid units mechanism. These systems retain the enhanced properties from having a negative Poisson's ratio with the added benefits of being a hierarchical system. Using simulations on typical hierarchical multi-level rotating squares, we show that, through design, one can control the extent of auxeticity, degree of aperture and size of the different pores in the system. This makes the system more versatile than similar non-hierarchical ones, making them promising candidates for industrial and biomedical applications, such as stents and skin grafts. PMID:25670400

  19. Perception and Hierarchical Dynamics

    PubMed Central

    Kiebel, Stefan J.; Daunizeau, Jean; Friston, Karl J.

    2009-01-01

    In this paper, we suggest that perception could be modeled by assuming that sensory input is generated by a hierarchy of attractors in a dynamic system. We describe a mathematical model which exploits the temporal structure of rapid sensory dynamics to track the slower trajectories of their underlying causes. This model establishes a proof of concept that slowly changing neuronal states can encode the trajectories of faster sensory signals. We link this hierarchical account to recent developments in the perception of human action; in particular artificial speech recognition. We argue that these hierarchical models of dynamical systems are a plausible starting point to develop robust recognition schemes, because they capture critical temporal dependencies induced by deep hierarchical structure. We conclude by suggesting that a fruitful computational neuroscience approach may emerge from modeling perception as non-autonomous recognition dynamics enslaved by autonomous hierarchical dynamics in the sensorium. PMID:19649171

  20. Hierarchical Auxetic Mechanical Metamaterials

    NASA Astrophysics Data System (ADS)

    Gatt, Ruben; Mizzi, Luke; Azzopardi, Joseph I.; Azzopardi, Keith M.; Attard, Daphne; Casha, Aaron; Briffa, Joseph; Grima, Joseph N.

    2015-02-01

    Auxetic mechanical metamaterials are engineered systems that exhibit the unusual macroscopic property of a negative Poisson's ratio due to sub-unit structure rather than chemical composition. Although their unique behaviour makes them superior to conventional materials in many practical applications, they are limited in availability. Here, we propose a new class of hierarchical auxetics based on the rotating rigid units mechanism. These systems retain the enhanced properties from having a negative Poisson's ratio with the added benefits of being a hierarchical system. Using simulations on typical hierarchical multi-level rotating squares, we show that, through design, one can control the extent of auxeticity, degree of aperture and size of the different pores in the system. This makes the system more versatile than similar non-hierarchical ones, making them promising candidates for industrial and biomedical applications, such as stents and skin grafts.

  1. Hierarchical auxetic mechanical metamaterials.

    PubMed

    Gatt, Ruben; Mizzi, Luke; Azzopardi, Joseph I; Azzopardi, Keith M; Attard, Daphne; Casha, Aaron; Briffa, Joseph; Grima, Joseph N

    2015-01-01

    Auxetic mechanical metamaterials are engineered systems that exhibit the unusual macroscopic property of a negative Poisson's ratio due to sub-unit structure rather than chemical composition. Although their unique behaviour makes them superior to conventional materials in many practical applications, they are limited in availability. Here, we propose a new class of hierarchical auxetics based on the rotating rigid units mechanism. These systems retain the enhanced properties from having a negative Poisson's ratio with the added benefits of being a hierarchical system. Using simulations on typical hierarchical multi-level rotating squares, we show that, through design, one can control the extent of auxeticity, degree of aperture and size of the different pores in the system. This makes the system more versatile than similar non-hierarchical ones, making them promising candidates for industrial and biomedical applications, such as stents and skin grafts. PMID:25670400

  2. Proposed applications with implementation techniques of the upcoming renewable energy resource, The Tesla Turbine

    NASA Astrophysics Data System (ADS)

    Usman Saeed Khan, M.; Maqsood, M. Irfan; Ali, Ehsan; Jamal, Shah; Javed, M.

    2013-06-01

    Recent research has shown that tesla turbine can be one of the future efficient sources of renewable energy. Modern techniques used for designing of tesla turbine have given optimum results regarding efficiency and applications. In this paper we have suggested fully coordinated applications of tesla turbine in different fields particularly in power generation at both low level and high level generation. In Energy deficient countries the tesla turbine has wide range of applications and it can play an important role in energy management system. Our proposed applications includes, the use of tesla turbine as renewable energy resource using tesla turbine in distributed generation system use of tesla turbine at home for power generation use of tesla turbine in irrigation channels using tesla turbine in hybrid electric vehicles All applications are explained with the help of flow charts and block diagrams and their implementation techniques are also explained in details. The results of physical experiments and simulations are also included for some applications.

  3. Design of multilevel heterogeneous ad-hoc wireless networks with UAVs

    NASA Astrophysics Data System (ADS)

    Gu, Daniel L.; Gerla, Mario; Ly, Henry; Xu, Kaixin; Kong, Jiejun; Hong, Xiaoyan

    2001-10-01

    Multi-Layer Ad Hoc Wireless Networks with UAVs is an ideal infrastructure to establish a rapidly deployable wireless communication system any time any where in the world for military applications. In this paper, we review the research we have done so far for our heterogeneous solution. First of all, we proposed the infrastructure of Multi-level Heterogeneous Ad-Hoc Wireless Network with UAVs. Second, we developed a new MAC layer protocol, Centralized Intelligent Channel Assigned Multiple Access (C-ICAMA), for ground mobile backbone nodes to access UAV. Third, we extended HSR (Hierarchical State Routing) to this Multi-Level Heterogeneous Ad-Hoc Wireless Network. Due to the intrinsic limitations of Extended HSR, we extended the Landmark Ad Hoc Routing (LANMAR) as our forth step. Security is a critical issue for mobile ad-hoc wireless networks, especially for military applications. We developed an embedded distributed security protocol and integrated with this heterogeneous hierarchical ad hoc wireless networks in our fifth step. Therefore, the hierarchical multi-layer approach is the most desirable approach to achieve routing scalability in multi-hop wireless networks.

  4. Quasi-Hierarchical Routing Algorithm for ZigBee/IEEE 802.15.4 Networks

    NASA Astrophysics Data System (ADS)

    Kim, Youn-Soo; Lee, Eun Ju; Kim, Bong Soo; Kim, Hyung Seok

    ZigBee recently has been used a lot in wireless sensor networks because of its low power consumption and affordable chips. However, ZigBee's existing hierarchical routing algorithm has a disadvantage in that a node may communicate with a nearby node over several hops. In this letter we propose a Quasi-Hierarchical Routing (QHR) algorithm that can improve the ZigBee hierarchical routing method's inefficiency by using brief information on neighbors within radio range. The network simulation evaluates this QHR's performance by comparing it to other ZigBee routing schemes.

  5. Community Wireless Networks

    ERIC Educational Resources Information Center

    Feld, Harold

    2005-01-01

    With increasing frequency, communities are seeing the arrival of a new class of noncommercial broadband providers: community wireless networks (CWNs). Utilizing the same wireless technologies that many colleges and universities have used to create wireless networks on campus, CWNs are creating broadband access for free or at costs well below…

  6. Report on the TESLA Engineering Study/Review

    SciTech Connect

    Cornuelle, John C.

    2002-08-30

    In March, 2001, the TESLA Collaboration published its Technical Design Report (TDR, see references and links in Appendix), the first sentence of which stated ''...TESLA (TeV-Energy Superconducting Linear Collider) (will be) a superconducting electron-positron collider of initially 500 GeV total energy, extendable to 800 GeV, and an integrated X-ray laser laboratory.'' The TDR included cost and manpower estimates for a 500 GeV e{sup +}e{sup -} collider (250 on 250 GeV) based on superconducting RF cavity technology. This was submitted as a proposal to the German government. The government asked the German Science Council to evaluate this proposal. The recommendation from this body is anticipated to be available by November 2002. The government has indicated that it will react on this recommendation by mid-2003. In June 2001, Steve Holmes, Fermilab's Associate Director for Accelerators, commissioned Helen Edwards and Peter Garbincius to organize a study of the TESLA Technical Design Report and the associated cost and manpower estimates. Since the elements and methodology used in producing the TESLA cost estimate were somewhat different from those used in preparing similar estimates for projects within the U.S., it is important to understand the similarities, differences, and equivalences between the TESLA estimate and U.S. cost estimates. In particular, the project cost estimate includes only purchased equipment, materials, and services, but not manpower from DESY or other TESLA collaborating institutions, which is listed separately. It does not include the R&D on the TESLA Test Facility (TTF) nor the costs of preparing the TDR nor the costs of performing the conceptual studies so far. The manpower for the pre-operations commissioning program (up to beam) is included in the estimate, but not the electrical power or liquid Nitrogen (for initial cooldown of the cryogenics plant). There is no inclusion of any contingency or management reserve. If the U.S. were to become

  7. Wireless adiabatic power transfer

    SciTech Connect

    Rangelov, A.A.; Suchowski, H.; Silberberg, Y.; Vitanov, N.V.

    2011-03-15

    Research Highlights: > Efficient and robust mid-range wireless energy transfer between two coils. > The adiabatic energy transfer is analogous to adiabatic passage in quantum optics. > Wireless energy transfer is insensitive to any resonant constraints. > Wireless energy transfer is insensitive to noise in the neighborhood of the coils. - Abstract: We propose a technique for efficient mid-range wireless power transfer between two coils, by adapting the process of adiabatic passage for a coherently driven two-state quantum system to the realm of wireless energy transfer. The proposed technique is shown to be robust to noise, resonant constraints, and other interferences that exist in the neighborhood of the coils.

  8. Parallel hierarchical radiosity rendering

    SciTech Connect

    Carter, M.

    1993-07-01

    In this dissertation, the step-by-step development of a scalable parallel hierarchical radiosity renderer is documented. First, a new look is taken at the traditional radiosity equation, and a new form is presented in which the matrix of linear system coefficients is transformed into a symmetric matrix, thereby simplifying the problem and enabling a new solution technique to be applied. Next, the state-of-the-art hierarchical radiosity methods are examined for their suitability to parallel implementation, and scalability. Significant enhancements are also discovered which both improve their theoretical foundations and improve the images they generate. The resultant hierarchical radiosity algorithm is then examined for sources of parallelism, and for an architectural mapping. Several architectural mappings are discussed. A few key algorithmic changes are suggested during the process of making the algorithm parallel. Next, the performance, efficiency, and scalability of the algorithm are analyzed. The dissertation closes with a discussion of several ideas which have the potential to further enhance the hierarchical radiosity method, or provide an entirely new forum for the application of hierarchical methods.

  9. Energy Aware Clustering Algorithms for Wireless Sensor Networks

    NASA Astrophysics Data System (ADS)

    Rakhshan, Noushin; Rafsanjani, Marjan Kuchaki; Liu, Chenglian

    2011-09-01

    The sensor nodes deployed in wireless sensor networks (WSNs) are extremely power constrained, so maximizing the lifetime of the entire networks is mainly considered in the design. In wireless sensor networks, hierarchical network structures have the advantage of providing scalable and energy efficient solutions. In this paper, we investigate different clustering algorithms for WSNs and also compare these clustering algorithms based on metrics such as clustering distribution, cluster's load balancing, Cluster Head's (CH) selection strategy, CH's role rotation, node mobility, clusters overlapping, intra-cluster communications, reliability, security and location awareness.

  10. Discovering hierarchical motion structure.

    PubMed

    Gershman, Samuel J; Tenenbaum, Joshua B; Jäkel, Frank

    2016-09-01

    Scenes filled with moving objects are often hierarchically organized: the motion of a migrating goose is nested within the flight pattern of its flock, the motion of a car is nested within the traffic pattern of other cars on the road, the motion of body parts are nested in the motion of the body. Humans perceive hierarchical structure even in stimuli with two or three moving dots. An influential theory of hierarchical motion perception holds that the visual system performs a "vector analysis" of moving objects, decomposing them into common and relative motions. However, this theory does not specify how to resolve ambiguity when a scene admits more than one vector analysis. We describe a Bayesian theory of vector analysis and show that it can account for classic results from dot motion experiments, as well as new experimental data. Our theory takes a step towards understanding how moving scenes are parsed into objects. PMID:25818905

  11. Three-dimensional flow measurements in a tesla turbine rotor

    NASA Astrophysics Data System (ADS)

    Fuchs, Thomas; Schosser, Constantin; Hain, Rainer; Kaehler, Christian

    2015-11-01

    Tesla turbines are fluid mechanical devices converting flow energy into rotation energy by two physical effects: friction and adhesion. The advantages of the tesla turbine are its simple and robust design, as well as its scalability, which makes it suitable for custom power supply solutions, and renewable energy applications. To this day, there is a lack of experimental data to validate theoretical studies, and CFD simulations of these turbines. This work presents a comprehensive analysis of the flow through a tesla turbine rotor gap, with a gap height of only 0.5 mm, by means of three-dimensional Particle Tracking Velocimetry (3D-PTV). For laminar flows, the experimental results match the theory very well, since the measured flow profiles show the predicted second order parabolic shape in radial direction and a fourth order behavior in circumferential direction. In addition to these laminar measurements, turbulent flows at higher mass flow rates were investigated.

  12. Optic Nerve Assessment Using 7-Tesla Magnetic Resonance Imaging

    PubMed Central

    Singh, Arun D.; Platt, Sean M.; Lystad, Lisa; Lowe, Mark; Oh, Sehong; Jones, Stephen E.; Alzahrani, Yahya; Plesec, Thomas

    2016-01-01

    Purpose The purpose of this study was to correlate high-resolution magnetic resonance imaging (MRI) and histologic findings in a case of juxtapapillary choroidal melanoma with clinical evidence of optic nerve invasion. Methods With institutional review board approval, an enucleated globe with choroidal melanoma and optic nerve invasion was imaged using a 7-tesla MRI followed by histopathologic evaluation. Results Optical coherence tomography, B-scan ultrasonography, and 1.5-tesla MRI of the orbit (1-mm sections) could not detect optic disc invasion. Ex vivo, 7-tesla MRI detected optic nerve invasion, which correlated with histopathologic features. Conclusions Our case demonstrates the potential to document the existence of optic nerve invasion in the presence of an intraocular tumor, a feature that has a major bearing on decision making, particularly for consideration of enucleation. PMID:27239461

  13. Problem analysis and new design of TESLA coupler

    SciTech Connect

    Sun, Ding

    1994-06-01

    Problem analysis of tested TESLA coupler shows that the microwave discharge is a possible problem. Two new designs are presented. During previous tests of TESLA input coupler (doorknob with cylindrical ceramic window) it was unable to continuously operate above 300--400 kW and a small area of the coupler (area A in Figure 1) where the metal doorknob and ceramic window are only 2 mm apart was coated with metal by unidentified mechanism. In order to understand the problem and help the following designs, it is necessary to analyze possible mechanisms for the problem.

  14. Paul Drude's Prediction of Nonreciprocal Mutual Inductance for Tesla Transformers

    PubMed Central

    McGuyer, Bart

    2014-01-01

    Inductors, transmission lines, and Tesla transformers have been modeled with lumped-element equivalent circuits for over a century. In a well-known paper from 1904, Paul Drude predicts that the mutual inductance for an unloaded Tesla transformer should be nonreciprocal. This historical curiosity is mostly forgotten today, perhaps because it appears incorrect. However, Drude's prediction is shown to be correct for the conditions treated, demonstrating the importance of constraints in deriving equivalent circuits for distributed systems. The predicted nonreciprocity is not fundamental, but instead is an artifact of the misrepresentation of energy by an equivalent circuit. The application to modern equivalent circuits is discussed. PMID:25542040

  15. 76 FR 60124 - Tesla Motors, Inc.; Grant of Petition for Temporary Exemption From the Electronic Stability...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-28

    ... entering the fleet. IV. Notice of Receipt On August 5, 2011, we published in the Federal Register (76 FR... TRANSPORTATION National Highway Traffic Safety Administration Tesla Motors, Inc.; Grant of Petition for Temporary... Stability Control Systems. SUMMARY: This notice grants the petition of Tesla Motors, Inc. (Tesla) for...

  16. Tight bifunctional hierarchical catalyst.

    PubMed

    Højholt, Karen T; Vennestrøm, Peter N R; Tiruvalam, Ramchandra; Beato, Pablo

    2011-12-28

    A new concept to prepare tight bifunctional catalysts has been developed, by anchoring CoMo(6) clusters on hierarchical ZSM-5 zeolites for simultaneous use in HDS and hydrocracking catalysis. The prepared material displays a significant improved activity in HDS catalysis compared to the impregnated counterpart. PMID:22048337

  17. Microparticles with hierarchical porosity

    DOEpatents

    Petsev, Dimiter N; Atanassov, Plamen; Pylypenko, Svitlana; Carroll, Nick; Olson, Tim

    2012-12-18

    The present disclosure provides oxide microparticles with engineered hierarchical porosity and methods of manufacturing the same. Also described are structures that are formed by templating, impregnating, and/or precipitating the oxide microparticles and method for forming the same. Suitable applications include catalysts, electrocatalysts, electrocatalysts support materials, capacitors, drug delivery systems, sensors and chromatography.

  18. Tesla coil discharges guided by femtosecond laser filaments in air

    NASA Astrophysics Data System (ADS)

    Brelet, Yohann; Houard, Aurélien; Arantchouk, Leonid; Forestier, Benjamin; Liu, Yi; Prade, Bernard; Carbonnel, Jérôme; André, Yves-Bernard; Mysyrowicz, André

    2012-04-01

    A Tesla coil generator was designed to produce high voltage pulses oscillating at 100 kHz synchronisable with a nanosecond temporal jitter. Using this compact high voltage generator, we demonstrate reproducible meter long discharges in air at a repetition rate of 1 Hz. Triggering and guiding of the discharges are performed in air by femtosecond laser filaments.

  19. TESLA FEL Gun simulations with PARMELA and MAFIA

    NASA Astrophysics Data System (ADS)

    Zhang, Min; Schuett, Petra

    1997-02-01

    The most recent simulation results of the DESY TESLA FEL gun are presented. Two codes are used: PARMELA and MAFIA. Since the two use different schemes in particle simulations, we will address their differences and try to give an explanation for them.

  20. Identifying Needed Technical Standards: The LITA TESLA Committee at Work.

    ERIC Educational Resources Information Center

    Carter, Ruth C.

    1984-01-01

    Efforts of the Technical Standards for Library Automation Committee (TESLA), a division-wide committee of the Library Information and Technology Association (LITA) of the American Library Association, are described. The current status of suggested technical standards and recommended action are detailed. Five sources are given. (Author/EJS)

  1. Wireless communication and spectrum sharing for public safety in the United States.

    PubMed

    Kapucu, Naim; Haupt, Brittany; Yuksel, Murat

    2016-01-01

    With the vast number of fragmented, independent public safety wireless communication systems, the United States is encountering major challenges with enhancing interoperability and effectively managing costs while sharing limited availability of critical spectrum. The traditional hierarchical approach of emergency management does not always allow for needed flexibility and is not a mandate. A national system would reduce equipment needs, increase effectiveness, and enrich quality and coordination of response; however, it is dependent on integrating the commercial market. This article discusses components of an ideal national wireless public safety system consists along with key policies in regulating wireless communication and spectrum sharing for public safety and challenges for implementation. PMID:27438959

  2. An effective Denial of Service Attack Detection Method in Wireless Mesh Networks

    NASA Astrophysics Data System (ADS)

    Luan, Liangyu; Fu, Yingfang; Xiao, Peng

    In order to detect the DoS attack (Denial-of-Service attack) when wireless mesh networks adopt AODV routing protocol of Ad Hoc networks. Such technologies as an end-to-end authentication, utilization rate of cache memory, two pre-assumed threshold value and distributed voting are used in this paper to detect DoS attacker, which is on the basic of hierarchical topology structure in wireless mesh networks. Through performance analysis in theory and simulations experiment, the scheme would improve the flexibility and accuracy of DoS attack detection, and would obviously improve its security in wireless mesh networks.

  3. Functionality of veterinary identification microchips following low- (0.5 tesla) and high-field (3 tesla) magnetic resonance imaging.

    PubMed

    Piesnack, Susann; Frame, Mairi E; Oechtering, Gerhard; Ludewig, Eberhard

    2013-01-01

    The ability to read patient identification microchips relies on the use of radiofrequency pulses. Since radiofrequency pulses also form an integral part of the magnetic resonance imaging (MRI) process, the possibility of loss of microchip function during MRI scanning is of concern. Previous clinical trials have shown microchip function to be unaffected by MR imaging using a field strength of 1 Tesla and 1.5. As veterinary MRI scanners range widely in field strength, this study was devised to determine whether exposure to lower or higher field strengths than 1 Tesla would affect the function of different types of microchip. In a phantom study, a total of 300 International Standards Organisation (ISO)-approved microchips (100 each of three different types: ISO FDX-B 1.4 × 9 mm, ISO FDX-B 2.12 × 12 mm, ISO HDX 3.8 × 23 mm) were tested in a low field (0.5) and a high field scanner (3.0 Tesla). A total of 50 microchips of each type were tested in each scanner. The phantom was composed of a fluid-filled freezer pack onto which a plastic pillow and a cardboard strip with affixed microchips were positioned. Following an MRI scan protocol simulating a head study, all of the microchips were accurately readable. Neither 0.5 nor 3 Tesla imaging affected microchip function in this study. PMID:23763334

  4. Deterministic hierarchical networks

    NASA Astrophysics Data System (ADS)

    Barrière, L.; Comellas, F.; Dalfó, C.; Fiol, M. A.

    2016-06-01

    It has been shown that many networks associated with complex systems are small-world (they have both a large local clustering coefficient and a small diameter) and also scale-free (the degrees are distributed according to a power law). Moreover, these networks are very often hierarchical, as they describe the modularity of the systems that are modeled. Most of the studies for complex networks are based on stochastic methods. However, a deterministic method, with an exact determination of the main relevant parameters of the networks, has proven useful. Indeed, this approach complements and enhances the probabilistic and simulation techniques and, therefore, it provides a better understanding of the modeled systems. In this paper we find the radius, diameter, clustering coefficient and degree distribution of a generic family of deterministic hierarchical small-world scale-free networks that has been considered for modeling real-life complex systems.

  5. Nested Hierarchical Dirichlet Processes.

    PubMed

    Paisley, John; Wang, Chong; Blei, David M; Jordan, Michael I

    2015-02-01

    We develop a nested hierarchical Dirichlet process (nHDP) for hierarchical topic modeling. The nHDP generalizes the nested Chinese restaurant process (nCRP) to allow each word to follow its own path to a topic node according to a per-document distribution over the paths on a shared tree. This alleviates the rigid, single-path formulation assumed by the nCRP, allowing documents to easily express complex thematic borrowings. We derive a stochastic variational inference algorithm for the model, which enables efficient inference for massive collections of text documents. We demonstrate our algorithm on 1.8 million documents from The New York Times and 2.7 million documents from Wikipedia. PMID:26353240

  6. Warming Up to Wireless

    ERIC Educational Resources Information Center

    Milner, Jacob

    2005-01-01

    In districts big and small across the U.S., students, teachers, and administrators alike have come to appreciate the benefits of wireless technology. Because the technology delivers Internet signals on airborne radio frequencies, wireless networking allows users of all portable devices to move freely on a school's campus and stay connected to the…

  7. High gain proportional rf control stability at TESLA cavities

    NASA Astrophysics Data System (ADS)

    Vogel, Elmar

    2007-05-01

    Fast proportional rf control is used as the basis for rf field regulation in actual linear accelerator projects like the international linear collider (ILC) and the European x-ray free electron laser (XFEL) based on TESLA technology. Additional control loops improve the field regulation by treating repetitive effects and compensating the beam loading. Nevertheless, the ability for high gain operation of the fast loops is desirable for the strong suppression of nonpredictive and nonrepetitive disturbances. TESLA cavities host nine fundamental modes (FMs) where only one is used for beam acceleration. The unwanted FMs have a significant influence on the proportional rf control loop stability at high gains. Within this paper, the stability of proportional rf control loops taking the FMs and digitalization effects into account will be discussed in detail together with measures enabling a significant increase of the gain values.

  8. HOM study and parameter calculation of the TESLA cavity model

    NASA Astrophysics Data System (ADS)

    Zeng, Ri-Hua; Schuh, Marcel; Gerigk, Frank; Wegner, Rolf; Pan, Wei-Min; Wang, Guang-Wei; Liu, Rong

    2010-01-01

    The Superconducting Proton Linac (SPL) is the project for a superconducting, high current H-accelerator at CERN. To find dangerous higher order modes (HOMs) in the SPL superconducting cavities, simulation and analysis for the cavity model using simulation tools are necessary. The existing TESLA 9-cell cavity geometry data have been used for the initial construction of the models in HFSS. Monopole, dipole and quadrupole modes have been obtained by applying different symmetry boundaries on various cavity models. In calculation, scripting language in HFSS was used to create scripts to automatically calculate the parameters of modes in these cavity models (these scripts are also available in other cavities with different cell numbers and geometric structures). The results calculated automatically are then compared with the values given in the TESLA paper. The optimized cavity model with the minimum error will be taken as the base for further simulation of the SPL cavities.

  9. Hierarchical image enhancement

    NASA Astrophysics Data System (ADS)

    Qi, Wei; Han, Jing; Zhang, Yi; Bai, Lian-fa

    2016-05-01

    Image enhancement is an important technique in computer vision. In this paper, we propose a hierarchical image enhancement approach based on the structure layer and texture layer. In the structure layer, we propose a structure-based method based on GMM, which better exploits structure details with fewer noise. In the texture layer, we present a structure-filtering method to filter unwanted texture with keeping completeness of detected salient structure. Next, we introduce a structure constraint prior to integrate them, leading to an improved enhancement result. Extensive experiments demonstrate that the proposed approach achieves higher quality results than previous approaches.

  10. Hierarchical Safety Cases

    NASA Technical Reports Server (NTRS)

    Denney, Ewen W.; Whiteside, Iain J.

    2012-01-01

    We introduce hierarchical safety cases (or hicases) as a technique to overcome some of the difficulties that arise creating and maintaining industrial-size safety cases. Our approach extends the existing Goal Structuring Notation with abstraction structures, which allow the safety case to be viewed at different levels of detail. We motivate hicases and give a mathematical account of them as well as an intuition, relating them to other related concepts. We give a second definition which corresponds closely to our implementation of hicases in the AdvoCATE Assurance Case Editor and prove the correspondence between the two. Finally, we suggest areas of future enhancement, both theoretically and practically.

  11. RHQT Nb3Al 15-Tesla magnet design study

    SciTech Connect

    Yamada, R.; Ambrosio, G.; Barzi, E.; Kashikin, V.; Kikuchi, A.; Novitski, I.; Takeuchi, T.; Wake, M.; Zlobin, A.; /Fermilab /NIMC, Tsukuba /KEK, Tsukuba

    2005-09-01

    Feasibility study of 15-Tesla dipole magnets wound with a new copper stabilized RHQT Nb{sub 3}Al Rutherford cable is presented. A new practical long copper stabilized RHQT Nb{sub 3}Al strand is presented, which is being developed and manufactured at the National Institute of Material Science (NIMS) in Japan. It has achieved a non-copper J{sub c} of 1000A/mm{sup 2} at 15 Tesla at 4.2K, with a copper over non-copper ratio of 1.04, and a filament size less than 50 microns. For this design study a short Rutherford cable with 28 Nb{sub 3}Al strands of 1 mm diameter will be fabricated late this year. The cosine theta magnet cross section is designed using ROXIE, and the stress and strain in the coil is estimated and studied with the characteristics of the Nb{sub 3}Al strand. The advantages and disadvantages of the Nb{sub 3}Al cable are compared with the prevailing Nb{sub 3}Sn cable from the point of view of stress-strain, J{sub c}, and possible degradation of stabilizer due to cabling. The Nb{sub 3}Al coil of the magnet, which will be made by wind and react method, has to be heat treated at 800 degree C for 10 hours. As preparation for the 15 Tesla magnet, a series of tests on strand and Rutherford cables are considered.

  12. Wireless nanosensor network system

    NASA Astrophysics Data System (ADS)

    Oh, Sechang; Kwon, Hyukjun; Kegley, Lauren; Yoon, Hargsoon; Varadan, Vijay K.

    2009-03-01

    Many types of wireless modules are being developed to enhance wireless performance with low power consumption, compact size, high data rates, and wide range coverage. However trade-offs must be taken into consideration in order to satisfy all aspects of wireless performance. For example, in order to increase the data rate and wide range coverage, power consumption should be sacrificed. To overcome these drawbacks, the paper presents a wireless client module which offers low power consumption along with a wireless receiver module that has the strength to provide high data rates and wide range coverage. Adopting Zigbee protocol in the wireless client module, the power consumption performance is enhanced so that it plays a part of the mobile device. On the other hand, the wireless receiver module, as adopting Zigbee and Wi-Fi protocol, provides high data rate, wide range coverage, and easy connection to the existing Internet network so that it plays a part of the portable device. This module demonstrates monitoring of gait analysis. The results show that the sensing data being measured can be monitored in any remote place with access to the Internet network.

  13. Digital wireless control system

    NASA Astrophysics Data System (ADS)

    Smith, R.

    1993-08-01

    The Digital Wireless Control System (DWCS) is designed to initiate high explosives safely while using a wireless remote control system. Numerous safety features have been designed into the fire control system to mitigate the hazards associated with remote initiation of high explosives. These safety features range from a telemetry (TM) fire control status system to mechanical timers and keyed power lockout switches. The environment, safety, and health (ES&H) Standard Operating Procedure (SOP) SP471970 is intended as a guide when working with the DWCS. This report describes the Digital Wireless Control System and outlines each component's theory of operation and its relationship to the system.

  14. Wireless Sensor Networks: Monitoring and Control

    SciTech Connect

    Hastbacka, Mildred; Ponoum, Ratcharit; Bouza, Antonio

    2013-05-31

    The article discusses wireless sensor technologies for building energy monitoring and control. This article, also, addresses wireless sensor networks as well as benefits and challenges of using wireless sensors. The energy savings and market potential of wireless sensors are reviewed.

  15. A Rasch Hierarchical Measurement Model.

    ERIC Educational Resources Information Center

    Maier, Kimberly S.

    This paper describes a model that integrates an item response theory (IRT) Rasch model and a hierarchical linear model and presents a method of estimating model parameter values that does not rely on large-sample theory and normal approximations. The model resulting from the integration of a hierarchical linear model and the Rasch model allows one…

  16. How hierarchical is language use?

    PubMed Central

    Frank, Stefan L.; Bod, Rens; Christiansen, Morten H.

    2012-01-01

    It is generally assumed that hierarchical phrase structure plays a central role in human language. However, considerations of simplicity and evolutionary continuity suggest that hierarchical structure should not be invoked too hastily. Indeed, recent neurophysiological, behavioural and computational studies show that sequential sentence structure has considerable explanatory power and that hierarchical processing is often not involved. In this paper, we review evidence from the recent literature supporting the hypothesis that sequential structure may be fundamental to the comprehension, production and acquisition of human language. Moreover, we provide a preliminary sketch outlining a non-hierarchical model of language use and discuss its implications and testable predictions. If linguistic phenomena can be explained by sequential rather than hierarchical structure, this will have considerable impact in a wide range of fields, such as linguistics, ethology, cognitive neuroscience, psychology and computer science. PMID:22977157

  17. Wireless Networks: New Meaning to Ubiquitous Computing.

    ERIC Educational Resources Information Center

    Drew, Wilfred, Jr.

    2003-01-01

    Discusses the use of wireless technology in academic libraries. Topics include wireless networks; standards (IEEE 802.11); wired versus wireless; why libraries implement wireless technology; wireless local area networks (WLANs); WLAN security; examples of wireless use at Indiana State University and Morrisville College (New York); and useful…

  18. Incremental hierarchical discriminant regression.

    PubMed

    Weng, Juyang; Hwang, Wey-Shiuan

    2007-03-01

    This paper presents incremental hierarchical discriminant regression (IHDR) which incrementally builds a decision tree or regression tree for very high-dimensional regression or decision spaces by an online, real-time learning system. Biologically motivated, it is an approximate computational model for automatic development of associative cortex, with both bottom-up sensory inputs and top-down motor projections. At each internal node of the IHDR tree, information in the output space is used to automatically derive the local subspace spanned by the most discriminating features. Embedded in the tree is a hierarchical probability distribution model used to prune very unlikely cases during the search. The number of parameters in the coarse-to-fine approximation is dynamic and data-driven, enabling the IHDR tree to automatically fit data with unknown distribution shapes (thus, it is difficult to select the number of parameters up front). The IHDR tree dynamically assigns long-term memory to avoid the loss-of-memory problem typical with a global-fitting learning algorithm for neural networks. A major challenge for an incrementally built tree is that the number of samples varies arbitrarily during the construction process. An incrementally updated probability model, called sample-size-dependent negative-log-likelihood (SDNLL) metric is used to deal with large sample-size cases, small sample-size cases, and unbalanced sample-size cases, measured among different internal nodes of the IHDR tree. We report experimental results for four types of data: synthetic data to visualize the behavior of the algorithms, large face image data, continuous video stream from robot navigation, and publicly available data sets that use human defined features. PMID:17385628

  19. A Wireless World: Charles County Public Schools Makes Wireless Universal

    ERIC Educational Resources Information Center

    Hoffman, Richard

    2007-01-01

    Wireless connectivity in schools is all the rage, and many school systems have at least gotten their feet wet with a wireless lab or a few portable laptop carts. But Bijaya Devkota, the chief information officer of Charles County Public Schools, has done what many school systems only dream of--implemented universal wireless access throughout his…

  20. Field quality measurements of a 2-Tesla transmission line magnet

    SciTech Connect

    Velev, G.V.; Foster, W.; Kashikhin, V.; Mazur, P.; Oleck, A.; Piekarz, H.; Schlabach, P.; Sylvester, C.; Wake, M.; /KEK, Tsukuba

    2005-09-01

    A prototype 2-Tesla superconducting transmission line magnet for future hadron colliders was designed, built and tested at Fermilab. The 1.5 m long, combined-function gradient-dipole magnet has a vertical pole aperture of 20 mm. To measure the magnetic field quality in such a small magnet aperture, a specialized rotating coil of 15.2 mm diameter, 0.69 m long was fabricated. Using this probe, a program of magnetic field quality measurements was successfully performed. Results of the measurements are presented and discussed.

  1. Hierarchical multifunctional nanocomposites

    NASA Astrophysics Data System (ADS)

    Ghasemi-Nejhad, Mehrdad N.

    2014-03-01

    properties of the fibers can also be improved by the growth of nanotubes on the fibers. The combination of the two will produce super-performing materials, not currently available. Since the improvement of fiber starts with carbon nanotube grown on micron-size fibers (and matrix with a nanomaterial) to give the macro-composite, this process is a bottom-up "hierarchical" advanced manufacturing process, and since the resulting nanocomposites will have "multifunctionality" with improve properties in various functional areas such as chemical and fire resistance, damping, stiffness, strength, fracture toughness, EMI shielding, and electrical and thermal conductivity, the resulting nanocomposites are in fact "multifunctional hierarchical nanocomposites." In this paper, the current state of knowledge in processing, performance, and characterization of these materials are addressed.

  2. Wireless Acoustic Measurement System

    NASA Technical Reports Server (NTRS)

    Anderson, Paul D.; Dorland, Wade D.; Jolly, Ronald L.

    2007-01-01

    A prototype wireless acoustic measurement system (WAMS) is one of two main subsystems of the Acoustic Prediction/ Measurement Tool, which comprises software, acoustic instrumentation, and electronic hardware combined to afford integrated capabilities for predicting and measuring noise emitted by rocket and jet engines. The other main subsystem is described in the article on page 8. The WAMS includes analog acoustic measurement instrumentation and analog and digital electronic circuitry combined with computer wireless local-area networking to enable (1) measurement of sound-pressure levels at multiple locations in the sound field of an engine under test and (2) recording and processing of the measurement data. At each field location, the measurements are taken by a portable unit, denoted a field station. There are ten field stations, each of which can take two channels of measurements. Each field station is equipped with two instrumentation microphones, a micro- ATX computer, a wireless network adapter, an environmental enclosure, a directional radio antenna, and a battery power supply. The environmental enclosure shields the computer from weather and from extreme acoustically induced vibrations. The power supply is based on a marine-service lead-acid storage battery that has enough capacity to support operation for as long as 10 hours. A desktop computer serves as a control server for the WAMS. The server is connected to a wireless router for communication with the field stations via a wireless local-area network that complies with wireless-network standard 802.11b of the Institute of Electrical and Electronics Engineers. The router and the wireless network adapters are controlled by use of Linux-compatible driver software. The server runs custom Linux software for synchronizing the recording of measurement data in the field stations. The software includes a module that provides an intuitive graphical user interface through which an operator at the control server

  3. Wireless Acoustic Measurement System

    NASA Technical Reports Server (NTRS)

    Anderson, Paul D.; Dorland, Wade D.

    2005-01-01

    A prototype wireless acoustic measurement system (WAMS) is one of two main subsystems of the Acoustic Prediction/Measurement Tool, which comprises software, acoustic instrumentation, and electronic hardware combined to afford integrated capabilities for predicting and measuring noise emitted by rocket and jet engines. The other main subsystem is described in "Predicting Rocket or Jet Noise in Real Time" (SSC-00215-1), which appears elsewhere in this issue of NASA Tech Briefs. The WAMS includes analog acoustic measurement instrumentation and analog and digital electronic circuitry combined with computer wireless local-area networking to enable (1) measurement of sound-pressure levels at multiple locations in the sound field of an engine under test and (2) recording and processing of the measurement data. At each field location, the measurements are taken by a portable unit, denoted a field station. There are ten field stations, each of which can take two channels of measurements. Each field station is equipped with two instrumentation microphones, a micro-ATX computer, a wireless network adapter, an environmental enclosure, a directional radio antenna, and a battery power supply. The environmental enclosure shields the computer from weather and from extreme acoustically induced vibrations. The power supply is based on a marine-service lead-acid storage battery that has enough capacity to support operation for as long as 10 hours. A desktop computer serves as a control server for the WAMS. The server is connected to a wireless router for communication with the field stations via a wireless local-area network that complies with wireless-network standard 802.11b of the Institute of Electrical and Electronics Engineers. The router and the wireless network adapters are controlled by use of Linux-compatible driver software. The server runs custom Linux software for synchronizing the recording of measurement data in the field stations. The software includes a module that

  4. Onboard hierarchical network

    NASA Astrophysics Data System (ADS)

    Tunesi, Luca; Armbruster, Philippe

    2004-02-01

    The objective of this paper is to demonstrate a suitable hierarchical networking solution to improve capabilities and performances of space systems, with significant recurrent costs saving and more efficient design & manufacturing flows. Classically, a satellite can be split in two functional sub-systems: the platform and the payload complement. The platform is in charge of providing power, attitude & orbit control and up/down-link services, whereas the payload represents the scientific and/or operational instruments/transponders and embodies the objectives of the mission. One major possibility to improve the performance of payloads, by limiting the data return to pertinent information, is to process data on board thanks to a proper implementation of the payload data system. In this way, it is possible to share non-recurring development costs by exploiting a system that can be adopted by the majority of space missions. It is believed that the Modular and Scalable Payload Data System, under development by ESA, provides a suitable solution to fulfil a large range of future mission requirements. The backbone of the system is the standardised high data rate SpaceWire network http://www.ecss.nl/. As complement, a lower speed command and control bus connecting peripherals is required. For instance, at instrument level, there is a need for a "local" low complexity bus, which gives the possibility to command and control sensors and actuators. Moreover, most of the connections at sub-system level are related to discrete signals management or simple telemetry acquisitions, which can easily and efficiently be handled by a local bus. An on-board hierarchical network can therefore be defined by interconnecting high-speed links and local buses. Additionally, it is worth stressing another important aspect of the design process: Agencies and ESA in particular are frequently confronted with a big consortium of geographically spread companies located in different countries, each one

  5. Hierarchical Linked Views

    SciTech Connect

    Erbacher, Robert; Frincke, Deb

    2007-07-02

    Coordinated views have proven critical to the development of effective visualization environments. This results from the fact that a single view or representation of the data cannot show all of the intricacies of a given data set. Additionally, users will often need to correlate more data parameters than can effectively be integrated into a single visual display. Typically, development of multiple-linked views results in an adhoc configuration of views and associated interactions. The hierarchical model we are proposing is geared towards more effective organization of such environments and the views they encompass. At the same time, this model can effectively integrate much of the prior work on interactive and visual frameworks. Additionally, we expand the concept of views to incorporate perceptual views. This is related to the fact that visual displays can have information encoded at various levels of focus. Thus, a global view of the display provides overall trends of the data while focusing in on individual elements provides detailed specifics. By integrating interaction and perception into a single model, we show how one impacts the other. Typically, interaction and perception are considered separately, however, when interaction is being considered at a fundamental level and allowed to direct/modify the visualization directly we must consider them simultaneously and how they impact one another.

  6. Jamming in hierarchical networks

    NASA Astrophysics Data System (ADS)

    Cheng, Xiang; Boettcher, Stefan

    2015-11-01

    We study the Biroli-Mezard model for lattice glasses on a number of hierarchical networks. These networks combine certain lattice-like features with a recursive structure that makes them suitable for exact renormalization group studies and provide an alternative to the mean-field approach. In our numerical simulations here, we first explore their equilibrium properties with the Wang-Landau algorithm. Then, we investigate their dynamical behavior using a grand-canonical annealing algorithm. We find that the dynamics readily falls out of equilibrium and jams in many of our networks with certain constraints on the neighborhood occupation imposed by the Biroli-Mezard model, even in cases where exact results indicate that no ideal glass transition exists. But while we find that time-scales for the jams diverge, our simulations cannot ascertain such a divergence for a packing fraction distinctly above random close packing. In cases where we allow hopping in our dynamical simulations, the jams on these networks generally disappear.

  7. Direct hierarchical assembly of nanoparticles

    DOEpatents

    Xu, Ting; Zhao, Yue; Thorkelsson, Kari

    2014-07-22

    The present invention provides hierarchical assemblies of a block copolymer, a bifunctional linking compound and a nanoparticle. The block copolymers form one micro-domain and the nanoparticles another micro-domain.

  8. Cavity parameters identification for TESLA control system development

    NASA Astrophysics Data System (ADS)

    Czarski, Tomasz; Pozniak, Krysztof T.; Romaniuk, Ryszard S.; Simrock, Stefan

    2005-08-01

    Aim of the control system development for TESLA cavity is a more efficient stabilization of the pulsed, accelerating EM field inside resonator. Cavity parameters identification is an essential task for the comprehensive control algorithm. TESLA cavity simulator has been successfully implemented using high-speed FPGA technology. Electromechanical model of the cavity resonator includes Lorentz force detuning and beam loading. The parameters identification is based on the electrical model of the cavity. The model is represented by state space equation for envelope of the cavity voltage driven by current generator and beam loading. For a given model structure, the over-determined matrix equation is created covering long enough measurement range with the solution according to the least-squares method. A low-degree polynomial approximation is applied to estimate the time-varying cavity detuning during the pulse. The measurement channel distortion is considered, leading to the external cavity model seen by the controller. The comprehensive algorithm of the cavity parameters identification was implemented in the Matlab system with different modes of operation. Some experimental results were presented for different cavity operational conditions. The following considerations have lead to the synthesis of the efficient algorithm for the cavity control system predicted for the potential FPGA technology implementation.

  9. Coaxial Coupling Scheme for TESLA/ILC-type Cavities

    SciTech Connect

    J.K. Sekutowicz, P. Kneisel

    2010-05-01

    This paper reports about our efforts to develop a flangeable coaxial coupler for both HOM and fundamental coupling for 9-cell TESLA/ILC-type cavities. The cavities were designed in early 90‘s for pulsed operation with a low duty factor, less than 1 %. The proposed design of the coupler has been done in a way, that the magnetic flux B at the flange connection is minimized and only a field of <5 mT would be present at the accelerating field Eacc of ~ 36 MV/m (B =150 mT in the cavity). Even though we achieved reasonably high Q-values at low field, the cavity/coupler combination was limited in the cw mode to only ~ 7 MV/m, where a thermally initiated degradation occurred. We have improved the cooling conditions by initially drilling radial channels every 30 degrees, then every 15 degrees into the shorting plate. The modified prototype performed well up to 9 MV/m in cw mode. This paper reports about our experiences with the further modified coaxial coupler and about test results in cw and low duty cycle pulsed mode, similar to the TESLA/ILC operation conditions.

  10. 77 FR 2269 - Foreign-Trade Zone 18-San Jose, CA, Application for Subzone, Tesla Motors, Inc. (Electric...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-17

    ... Foreign-Trade Zones Board Foreign-Trade Zone 18--San Jose, CA, Application for Subzone, Tesla Motors, Inc... purpose subzone status for the electric passenger- vehicle manufacturing facilities of Tesla Motors, Inc. (Tesla), located in Palo Alto and Fremont, California. The application was submitted pursuant to...

  11. Terabit Wireless Communication Challenges

    NASA Technical Reports Server (NTRS)

    Hwu, Shian U.

    2012-01-01

    This presentation briefly discusses a research effort on Terabit Wireless communication systems for possible space applications. Recently, terahertz (THz) technology (300-3000 GHz frequency) has attracted a great deal of interest from academia and industry. This is due to a number of interesting features of THz waves, including the nearly unlimited bandwidths available, and the non-ionizing radiation nature which does not damage human tissues and DNA with minimum health threat. Also, as millimeter-wave communication systems mature, the focus of research is, naturally, moving to the THz range. Many scientists regard THz as the last great frontier of the electromagnetic spectrum, but finding new applications outside the traditional niches of radio astronomy, Earth and planetary remote sensing, and molecular spectroscopy particularly in biomedical imaging and wireless communications has been relatively slow. Radiologists find this area of study so attractive because t-rays are non-ionizing, which suggests no harm is done to tissue or DNA. They also offer the possibility of performing spectroscopic measurements over a very wide frequency range, and can even capture signatures from liquids and solids. According to Shannon theory, the broad bandwidth of the THz frequency bands can be used for terabit-per-second (Tb/s) wireless communication systems. This enables several new applications, such as cell phones with 360 degrees autostereoscopic displays, optic-fiber replacement, and wireless Tb/s file transferring. Although THz technology could satisfy the demand for an extremely high data rate, a number of technical challenges need to be overcome before its development. This presentation provides an overview the state-of-the- art in THz wireless communication and the technical challenges for an emerging application in Terabit wireless systems. The main issue for THz wave propagation is the high atmospheric attenuation, which is dominated by water vapor absorption in the THz

  12. Advanced hierarchical distance sampling

    USGS Publications Warehouse

    Royle, Andy

    2016-01-01

    In this chapter, we cover a number of important extensions of the basic hierarchical distance-sampling (HDS) framework from Chapter 8. First, we discuss the inclusion of “individual covariates,” such as group size, in the HDS model. This is important in many surveys where animals form natural groups that are the primary observation unit, with the size of the group expected to have some influence on detectability. We also discuss HDS integrated with time-removal and double-observer or capture-recapture sampling. These “combined protocols” can be formulated as HDS models with individual covariates, and thus they have a commonality with HDS models involving group structure (group size being just another individual covariate). We cover several varieties of open-population HDS models that accommodate population dynamics. On one end of the spectrum, we cover models that allow replicate distance sampling surveys within a year, which estimate abundance relative to availability and temporary emigration through time. We consider a robust design version of that model. We then consider models with explicit dynamics based on the Dail and Madsen (2011) model and the work of Sollmann et al. (2015). The final major theme of this chapter is relatively newly developed spatial distance sampling models that accommodate explicit models describing the spatial distribution of individuals known as Point Process models. We provide novel formulations of spatial DS and HDS models in this chapter, including implementations of those models in the unmarked package using a hack of the pcount function for N-mixture models.

  13. An Integrated Intrusion Detection Model of Cluster-Based Wireless Sensor Network

    PubMed Central

    Sun, Xuemei; Yan, Bo; Zhang, Xinzhong; Rong, Chuitian

    2015-01-01

    Considering wireless sensor network characteristics, this paper combines anomaly and mis-use detection and proposes an integrated detection model of cluster-based wireless sensor network, aiming at enhancing detection rate and reducing false rate. Adaboost algorithm with hierarchical structures is used for anomaly detection of sensor nodes, cluster-head nodes and Sink nodes. Cultural-Algorithm and Artificial-Fish–Swarm-Algorithm optimized Back Propagation is applied to mis-use detection of Sink node. Plenty of simulation demonstrates that this integrated model has a strong performance of intrusion detection. PMID:26447696

  14. An Integrated Intrusion Detection Model of Cluster-Based Wireless Sensor Network.

    PubMed

    Sun, Xuemei; Yan, Bo; Zhang, Xinzhong; Rong, Chuitian

    2015-01-01

    Considering wireless sensor network characteristics, this paper combines anomaly and mis-use detection and proposes an integrated detection model of cluster-based wireless sensor network, aiming at enhancing detection rate and reducing false rate. Adaboost algorithm with hierarchical structures is used for anomaly detection of sensor nodes, cluster-head nodes and Sink nodes. Cultural-Algorithm and Artificial-Fish-Swarm-Algorithm optimized Back Propagation is applied to mis-use detection of Sink node. Plenty of simulation demonstrates that this integrated model has a strong performance of intrusion detection. PMID:26447696

  15. Wireless image transmission using turbo codes and optimal unequal error protection.

    PubMed

    Thomos, Nikolaos; Boulgouris, Nikolaos V; Strintzis, Michael G

    2005-11-01

    A novel image transmission scheme is proposed for the communication of set partitioning in hierarchical trees image streams over wireless channels. The proposed scheme employs turbo codes and Reed-Solomon codes in order to deal effectively with burst errors. An algorithm for the optimal unequal error protection of the compressed bitstream is also proposed and applied in conjunction with an inherently more efficient technique for product code decoding. The resulting scheme is tested for the transmission of images over wireless channels. Experimental evaluation clearly demonstrates the superiority of the proposed transmission system in comparison to well-known robust coding schemes. PMID:16279187

  16. Insecurity of Wireless Networks

    SciTech Connect

    Sheldon, Frederick T; Weber, John Mark; Yoo, Seong-Moo; Pan, W. David

    2012-01-01

    Wireless is a powerful core technology enabling our global digital infrastructure. Wi-Fi networks are susceptible to attacks on Wired Equivalency Privacy, Wi-Fi Protected Access (WPA), and WPA2. These attack signatures can be profiled into a system that defends against such attacks on the basis of their inherent characteristics. Wi-Fi is the standard protocol for wireless networks used extensively in US critical infrastructures. Since the Wired Equivalency Privacy (WEP) security protocol was broken, the Wi-Fi Protected Access (WPA) protocol has been considered the secure alternative compatible with hardware developed for WEP. However, in November 2008, researchers developed an attack on WPA, allowing forgery of Address Resolution Protocol (ARP) packets. Subsequent enhancements have enabled ARP poisoning, cryptosystem denial of service, and man-in-the-middle attacks. Open source systems and methods (OSSM) have long been used to secure networks against such attacks. This article reviews OSSMs and the results of experimental attacks on WPA. These experiments re-created current attacks in a laboratory setting, recording both wired and wireless traffic. The article discusses methods of intrusion detection and prevention in the context of cyber physical protection of critical Internet infrastructure. The basis for this research is a specialized (and undoubtedly incomplete) taxonomy of Wi-Fi attacks and their adaptations to existing countermeasures and protocol revisions. Ultimately, this article aims to provide a clearer picture of how and why wireless protection protocols and encryption must achieve a more scientific basis for detecting and preventing such attacks.

  17. Wireless Sensors Network (Sensornet)

    NASA Technical Reports Server (NTRS)

    Perotti, J.

    2003-01-01

    The Wireless Sensor Network System presented in this paper provides a flexible reconfigurable architecture that could be used in a broad range of applications. It also provides a sensor network with increased reliability; decreased maintainability costs, and assured data availability by autonomously and automatically reconfiguring to overcome communication interferences.

  18. Building the Wireless Campus

    ERIC Educational Resources Information Center

    Gerraughty, James F.; Shanafelt, Michael E.

    2005-01-01

    This prototype is a continuation of a series of wireless prototypes which began in August 2001 and was reported on again in August 2002. This is the final year of this prototype. This continuation allowed Saint Francis University's Center of Excellence for Remote and Medically Under-Served Areas (CERMUSA) to refine the existing WLAN for the Saint…

  19. Broadcast Authentication for Wireless Sensor Networks Using Nested Hashing and the Chinese Remainder Theorem

    PubMed Central

    Eldefrawy, Mohamed Hamdy; Khan, Muhammad Khurram; Alghathbar, Khaled; Cho, Eun-Suk

    2010-01-01

    Secure broadcasting is an essential feature for critical operations in wireless sensor network (WSNs). However, due to the limited resources of sensor networks, verifying the authenticity for broadcasted messages is a very difficult issue. μTESLA is a broadcast authentication protocol, which uses network-wide loose time synchronization with one-way hashed keys to provide the authenticity verification. However, it suffers from several flaws considering the delay tolerance, and the chain length restriction. In this paper, we propose a protocol which provides broadcast authentication for wireless sensor networks. This protocol uses a nested hash chain of two different hash functions and the Chinese Remainder Theorem (CRT). The two different nested hash functions are employed for the seed updating and the key generation. Each sensor node is challenged independently with a common broadcasting message using the CRT. Our algorithm provides forward and non-restricted key generation, and in addition, no time synchronization is required. Furthermore, receivers can instantly authenticate packets in real time. Moreover, the comprehensive analysis shows that this scheme is efficient and practical, and can achieve better performance than the μTESLA system. PMID:22163679

  20. A Single Crystal Niobium RF Cavity of the TESLA Shape

    SciTech Connect

    Singer, W.; Singer, X.; Kneisel, P.

    2007-08-09

    A fabrication method for single crystal niobium cavities of the TESLA shape was proposed on the basis of metallographic investigations and electron beam welding tests on niobium single crystals. These tests showed that a cavity can be produced without grain boundaries even in the welding area. An appropriate annealing allows the outgassing of hydrogen and stress relaxation of the material without destruction of the single crystal. A prototype single crystal single cell cavity was build. An accelerating gradient of 37.5 MV/m was reached after approximately 110 {mu}m of Buffered Chemical Polishing (BCP) and in situ baking at 120 deg. C for 6 hrs with a quality factor exceeding 2x1010 at 1.8 K. The developed fabrication method can be extended to fabrication of multi cell cavities.

  1. Sampling Hyperpolarized Molecules Utilizing a 1 Tesla Permanent Magnetic Field

    PubMed Central

    Tee, Sui Seng; DiGialleonardo, Valentina; Eskandari, Roozbeh; Jeong, Sangmoo; Granlund, Kristin L.; Miloushev, Vesselin; Poot, Alex J.; Truong, Steven; Alvarez, Julio A.; Aldeborgh, Hannah N.; Keshari, Kayvan R.

    2016-01-01

    Hyperpolarized magnetic resonance spectroscopy (HP MRS) using dynamic nuclear polarization (DNP) is a technique that has greatly enhanced the sensitivity of detecting 13C nuclei. However, the HP MRS polarization decays in the liquid state according to the spin-lattice relaxation time (T1) of the nucleus. Sampling of the signal also destroys polarization, resulting in a limited temporal ability to observe biologically interesting reactions. In this study, we demonstrate that sampling hyperpolarized signals using a permanent magnet at 1 Tesla (1T) is a simple and cost-effective method to increase T1s without sacrificing signal-to-noise. Biologically-relevant information may be obtained with a permanent magnet using enzyme solutions and in whole cells. Of significance, our findings indicate that changes in pyruvate metabolism can also be quantified in a xenograft model at this field strength. PMID:27597137

  2. A Single Crystal Niobium RF Cavity of the TESLA Shape

    SciTech Connect

    W. Singer; X. Singer; P. Kneisel

    2007-09-01

    A fabrication method for single crystal niobium cavities of the TESLA shape was proposed on the basis of metallographic investigations and electron beam welding tests on niobium single crystals. These tests showed that a cavity can be produced without grain boundaries even in the welding area. An appropriate annealing allows the outgassing of hydrogen and stress relaxation of the material without destruction of the single crystal. A prototype single crystal single cell cavity was built. An accelerating gradient of 37.5 MV/m was reached after approximately 110 mu-m of Buffered Chanical Polishing (BCP) and in situ baking at 120°C for 6 hrs with a quality factor exceeding 2x1010 at 1.8 K. The developed fabrication method can be extended to fabrication of multi cell cavities.

  3. Comparison of the TESLA, NLC and CLIC beam collimation performance

    SciTech Connect

    Alexandr I Drozhdin et al.

    2003-03-27

    This note describes studies performed in the framework of the Collimation Task Force organized to support the work of the International Linear Collider Technical Review Committee. The post-linac beam-collimation systems in the TESLA, JLC/NLC and CLIC linear-collider designs are compared using the same computer code under the same assumptions. Their performance is quantified in terms of beam-halo and synchrotron-radiation collimation efficiency. The performance of the current designs varies across projects, and does not always meet the original design goals. But these comparisons suggest that achieving the required performance in a future linear collider is feasible. The post-TRC plans of the Collimation Task Force are briefly outlined in closing.

  4. A database for superconducting cavities for the TESLA Test Facility

    NASA Astrophysics Data System (ADS)

    Gall, P. D.; Goessel, A.; Gubarev, V.; Iversen, J.

    2006-07-01

    We look back on 10 years experience using a database for superconducting cavities for the TESLA Test Facility (TTF). The database was developed to collect data of every preparation step and measurement in order to optimize cavity production and preparation techniques to meet the ambitious goal of high accelerating gradients at high quality factors. Data from 110 superconducting 9-cell cavities, 50 single cell cavities, several 2- to 7-cell cavities and about 60 RF couplers were collected in the database. In addition, company measurements on sub-assemblies and parts forming the next 30 9-cell cavities were stored, thus establishing the database as part of a quality management system. This database is dynamically accessible via an extensive graphical web-interface based on ORACLE products, which enables the users to select and analyse the collected data easily from anywhere.

  5. The NHMFL 60 tesla, 100 millisecond pulsed magnet

    SciTech Connect

    Boenig, H.J.; Campbell, L.J.; Rickel, D.G.; Rogers, J.D.; Schillig, J.B.; Sims, J.R.; Pernambuco-Wise, P.; Schneider-Muntau, H.J.

    1992-11-09

    Among the new facilities to be offered by the National Science Foundation through the National High Magnetic Field Laboratory (NHMFL) are pulsed fields that can only be achieved at a national user facility by virtue of their strength, duration, and volume. In particular, a 44 mm bore pulsed magnet giving a 60 tesla field for 100 ms is in the final design stage. This magnet will be powered by a 1.4 GW motor-generator at Los Alamos and is an important step toward proving design principles that will be needed for the higher field quasi-stationary pulsed magnets that this power source is capable of driving. This report will discuss specifications and parameters of this magnet.

  6. Report on the TESLA engineering study/review

    SciTech Connect

    C. Boffo et al.

    2002-07-18

    A team from Argonne National Lab, Cornell, Fermilab, Jefferson Lab, and SLAC has studied the TESLA TDR and its associated cost and manpower estimates, concentrating on the five largest cost sub-systems (Main Linac Modules, Main Linac RF Systems, Civil Engineering, Machine Infrastructure, and XFEL Incremental). These elements were concerned mainly with providing energy reach. We did not study the lower cost, but still technically challenging elements providing luminosity and physics capability, namely damping rings, beam delivery system, beam injection system, positron production, polarized beams, etc. The study did not attempt to validate the TDR cost estimates, but rather its purpose was to understand the technology and status of the large cost items, and the methodology by which their estimated cost was determined. In addition, topics of project oversight were studied.

  7. Sampling Hyperpolarized Molecules Utilizing a 1 Tesla Permanent Magnetic Field.

    PubMed

    Tee, Sui Seng; DiGialleonardo, Valentina; Eskandari, Roozbeh; Jeong, Sangmoo; Granlund, Kristin L; Miloushev, Vesselin; Poot, Alex J; Truong, Steven; Alvarez, Julio A; Aldeborgh, Hannah N; Keshari, Kayvan R

    2016-01-01

    Hyperpolarized magnetic resonance spectroscopy (HP MRS) using dynamic nuclear polarization (DNP) is a technique that has greatly enhanced the sensitivity of detecting (13)C nuclei. However, the HP MRS polarization decays in the liquid state according to the spin-lattice relaxation time (T1) of the nucleus. Sampling of the signal also destroys polarization, resulting in a limited temporal ability to observe biologically interesting reactions. In this study, we demonstrate that sampling hyperpolarized signals using a permanent magnet at 1 Tesla (1T) is a simple and cost-effective method to increase T1s without sacrificing signal-to-noise. Biologically-relevant information may be obtained with a permanent magnet using enzyme solutions and in whole cells. Of significance, our findings indicate that changes in pyruvate metabolism can also be quantified in a xenograft model at this field strength. PMID:27597137

  8. Design and prototype fabrication of a 30 tesla cryogenic magnet

    NASA Technical Reports Server (NTRS)

    Prok, G. M.; Swanson, M. C.; Brown, G. V.

    1977-01-01

    A liquid neon cooled magnet was designed to produce 30 teslas in steady operation. To ensure the correctness of the heat transfer relationships used, supercritical neon heat transfer tests were made. Other tests made before the final design included tests on the effect of the magnetic field on pump motors, tensile shear tests on the cryogenic adhesives, and simulated flow studies for the coolant. The magnet will consist of two pairs of coils, cooled by forced convection of supercritical neon. Heat from the supercritical neon will be rejected through heat exchangers which are made of roll bonded copper panels and are submerged in a pool of saturated liquid neon. A partial mock up coil was wound to identify the tooling required to wind the magnet. This was followed by winding a prototype pair of coils. The prototype winding established procedures for fabricating the final magnet and revealed slight changes needed in the final design.

  9. NASA Bluetooth Wireless Communications

    NASA Technical Reports Server (NTRS)

    Miller, Robert D.

    2007-01-01

    NASA has been interested in wireless communications for many years, especially when the crew size of the International Space Station (ISS) was reduced to two members. NASA began a study to find ways to improve crew efficiency to make sure the ISS could be maintained with limited crew capacity and still be a valuable research testbed in Low-Earth Orbit (LEO). Currently the ISS audio system requires astronauts to be tethered to the audio system, specifically a device called the Audio Terminal Unit (ATU). Wireless communications would remove the tether and allow astronauts to freely float from experiment to experiment without having to worry about moving and reconnecting the associated cabling or finding the space equivalent of an extension cord. A wireless communication system would also improve safety and reduce system susceptibility to Electromagnetic Interference (EMI). Safety would be improved because a crewmember could quickly escape a fire while maintaining communications with the ground and other crewmembers at any location. In addition, it would allow the crew to overcome the volume limitations of the ISS ATU. This is especially important to the Portable Breathing Apparatus (PBA). The next generation of space vehicles and habitats also demand wireless attention. Orion will carry up to six crewmembers in a relatively small cabin. Yet, wireless could become a driving factor to reduce launch weight and increase habitable volume. Six crewmembers, each tethered to a panel, could result in a wiring mess even in nominal operations. In addition to Orion, research is being conducted to determine if Bluetooth is appropriate for Lunar Habitat applications.

  10. Design, performance and production of the Fermilab TESLA RF input couplers

    SciTech Connect

    Champion, M.

    1996-10-01

    The TeV Energy Superconducting Linear Accelerator (TESLA) requires as one of its technical components a radiofrequency (rf) input coupler that transfers 1.3 GHz rf energy from the rf distribution system to a nine-cell superconducting accelerating cavity operating at a temperature of 1.8 K. The input coupler design is driven by numerous design criteria, which result in a rather complicated implementation. The production of twelve input couplers for the TESLA Test Facility (TTF) is underway at Fermilab, with the first two couplers having been delivered late in 1995. This paper discusses the Fermilab TESLA rf input coupler design, recent test results, and production issues.

  11. A Sensible Approach to Wireless Networking.

    ERIC Educational Resources Information Center

    Ahmed, S. Faruq

    2002-01-01

    Discusses radio frequency (R.F.) wireless technology, including industry standards, range (coverage) and throughput (data rate), wireless compared to wired networks, and considerations before embarking on a large-scale wireless project. (EV)

  12. Application of an automated wireless structural monitoring system for long-span suspension bridges

    SciTech Connect

    Kurata, M.; Lynch, J. P.; Linden, G. W. van der; Hipley, P.; Sheng, L.-H.

    2011-06-23

    This paper describes an automated wireless structural monitoring system installed at the New Carquinez Bridge (NCB). The designed system utilizes a dense network of wireless sensors installed in the bridge but remotely controlled by a hierarchically designed cyber-environment. The early efforts have included performance verification of a dense network of wireless sensors installed on the bridge and the establishment of a cellular gateway to the system for remote access from the internet. Acceleration of the main bridge span was the primary focus of the initial field deployment of the wireless monitoring system. An additional focus of the study is on ensuring wireless sensors can survive for long periods without human intervention. Toward this end, the life-expectancy of the wireless sensors has been enhanced by embedding efficient power management schemes in the sensors while integrating solar panels for power harvesting. The dynamic characteristics of the NCB under daily traffic and wind loads were extracted from the vibration response of the bridge deck and towers. These results have been compared to a high-fidelity finite element model of the bridge.

  13. Application of AN Automated Wireless Structural Monitoring System for Long-Span Suspension Bridges

    NASA Astrophysics Data System (ADS)

    Kurata, M.; Lynch, J. P.; van der Linden, G. W.; Hipley, P.; Sheng, L.-H.

    2011-06-01

    This paper describes an automated wireless structural monitoring system installed at the New Carquinez Bridge (NCB). The designed system utilizes a dense network of wireless sensors installed in the bridge but remotely controlled by a hierarchically designed cyber-environment. The early efforts have included performance verification of a dense network of wireless sensors installed on the bridge and the establishment of a cellular gateway to the system for remote access from the internet. Acceleration of the main bridge span was the primary focus of the initial field deployment of the wireless monitoring system. An additional focus of the study is on ensuring wireless sensors can survive for long periods without human intervention. Toward this end, the life-expectancy of the wireless sensors has been enhanced by embedding efficient power management schemes in the sensors while integrating solar panels for power harvesting. The dynamic characteristics of the NCB under daily traffic and wind loads were extracted from the vibration response of the bridge deck and towers. These results have been compared to a high-fidelity finite element model of the bridge.

  14. Wireless Seismometer for Venus

    NASA Technical Reports Server (NTRS)

    Ponchak, George E.; Scardelletti, Maximilian C.; Taylor, Brandt; Beard, Steve; Clougherty, Brian; Meredith, Roger D.; Beheim, Glenn M.; Kiefer, Walter S.; Hunter, Gary W.

    2014-01-01

    Measuring the seismic activity of Venus is critical to understanding its composition and interior dynamics. Because Venus has an average surface temperature of 462 C and the challenge of providing cooling to multiple seismometers, a high temperature, wireless sensor using a wide bandgap semiconductor is an attractive option. This paper presents progress towards a seismometer sensor with wireless capabilities for Venus applications. A variation in inductance of a coil caused by a 1 cm movement of a ferrite probe held in the coil and attached to a balanced leaf-spring seismometer causes a variation of 80 MHz in the transmitted signal from the oscillator sensor system at 420 C, which correlates to a 10 kHz mm sensitivity when the ferrite probe is located at the optimum location in the coil.

  15. Hierarchical Microaggressions in Higher Education

    ERIC Educational Resources Information Center

    Young, Kathryn; Anderson, Myron; Stewart, Saran

    2015-01-01

    Although there has been substantial research examining the effects of microaggressions in the public sphere, there has been little research that examines microaggressions in the workplace. This study explores the types of microaggressions that affect employees at universities. We coin the term "hierarchical microaggression" to represent…

  16. Hierarchical storage management system evaluation

    NASA Technical Reports Server (NTRS)

    Woodrow, Thomas S.

    1993-01-01

    The Numerical Aerodynamic Simulation (NAS) Program at NASA Ames Research Center has been developing a hierarchical storage management system, NAStore, for some 6 years. This evaluation compares functionality, performance, reliability, and other factors of NAStore and three commercial alternatives. FileServ is found to be slightly better overall than NAStore and DMF. UniTree is found to be severely lacking in comparison.

  17. Memory Stacking in Hierarchical Networks.

    PubMed

    Westö, Johan; May, Patrick J C; Tiitinen, Hannu

    2016-02-01

    Robust representations of sounds with a complex spectrotemporal structure are thought to emerge in hierarchically organized auditory cortex, but the computational advantage of this hierarchy remains unknown. Here, we used computational models to study how such hierarchical structures affect temporal binding in neural networks. We equipped individual units in different types of feedforward networks with local memory mechanisms storing recent inputs and observed how this affected the ability of the networks to process stimuli context dependently. Our findings illustrate that these local memories stack up in hierarchical structures and hence allow network units to exhibit selectivity to spectral sequences longer than the time spans of the local memories. We also illustrate that short-term synaptic plasticity is a potential local memory mechanism within the auditory cortex, and we show that it can bring robustness to context dependence against variation in the temporal rate of stimuli, while introducing nonlinearities to response profiles that are not well captured by standard linear spectrotemporal receptive field models. The results therefore indicate that short-term synaptic plasticity might provide hierarchically structured auditory cortex with computational capabilities important for robust representations of spectrotemporal patterns. PMID:26654206

  18. Beamstrahlung Photon Load on the TESLA Extraction Septum Blade(LCC-0104)

    SciTech Connect

    Seryi, A

    2003-10-02

    This note describes work performed in the framework of the International Linear Collider Technical Review Committee [1] to estimate the power load on the TESLA extraction septum blade due to beamstrahlung photons. It is shown, that under realistic conditions the photon load can be several orders of magnitude higher than what was estimated in the TESLA TDR [2] for the ideal Gaussian beams, potentially representing a serious limitation of the current design.

  19. Team one (GA/MCA) effort of the DOE 12 Tesla Coil Development Program. 12 Tesla ETF toroidal field coil helium bath cooled NbTi alloy concept

    SciTech Connect

    Not Available

    1980-07-01

    This report presents the conceptual design of an ETF compatible toroidal field coil, employing helium bath cooled NbTi alloy conductor. The ten TF-coil array generates a peak field of 11-1/2 tesla at 2.87 m radius, corresponding to a major axis field of 6.1 tesla. The 10 kA conductor is an uninsulated, unsoldered Rutherford cable, employing NbTiTa ally as developed in Phase I of this effort. The conductor is encased within a four element frame of stainless steel strips to provide hoop and bearing load support.

  20. Image Information Mining Utilizing Hierarchical Segmentation

    NASA Technical Reports Server (NTRS)

    Tilton, James C.; Marchisio, Giovanni; Koperski, Krzysztof; Datcu, Mihai

    2002-01-01

    The Hierarchical Segmentation (HSEG) algorithm is an approach for producing high quality, hierarchically related image segmentations. The VisiMine image information mining system utilizes clustering and segmentation algorithms for reducing visual information in multispectral images to a manageable size. The project discussed herein seeks to enhance the VisiMine system through incorporating hierarchical segmentations from HSEG into the VisiMine system.

  1. Developing a new wireless sensor network platform and its application in precision agriculture.

    PubMed

    Aquino-Santos, Raúl; González-Potes, Apolinar; Edwards-Block, Arthur; Virgen-Ortiz, Raúl Alejandro

    2011-01-01

    Wireless sensor networks are gaining greater attention from the research community and industrial professionals because these small pieces of "smart dust" offer great advantages due to their small size, low power consumption, easy integration and support for "green" applications. Green applications are considered a hot topic in intelligent environments, ubiquitous and pervasive computing. This work evaluates a new wireless sensor network platform and its application in precision agriculture, including its embedded operating system and its routing algorithm. To validate the technological platform and the embedded operating system, two different routing strategies were compared: hierarchical and flat. Both of these routing algorithms were tested in a small-scale network applied to a watermelon field. However, we strongly believe that this technological platform can be also applied to precision agriculture because it incorporates a modified version of LORA-CBF, a wireless location-based routing algorithm that uses cluster-based flooding. Cluster-based flooding addresses the scalability concerns of wireless sensor networks, while the modified LORA-CBF routing algorithm includes a metric to monitor residual battery energy. Furthermore, results show that the modified version of LORA-CBF functions well with both the flat and hierarchical algorithms, although it functions better with the flat algorithm in a small-scale agricultural network. PMID:22346622

  2. Developing a New Wireless Sensor Network Platform and Its Application in Precision Agriculture

    PubMed Central

    Aquino-Santos, Raúl; González-Potes, Apolinar; Edwards-Block, Arthur; Virgen-Ortiz, Raúl Alejandro

    2011-01-01

    Wireless sensor networks are gaining greater attention from the research community and industrial professionals because these small pieces of “smart dust” offer great advantages due to their small size, low power consumption, easy integration and support for “green” applications. Green applications are considered a hot topic in intelligent environments, ubiquitous and pervasive computing. This work evaluates a new wireless sensor network platform and its application in precision agriculture, including its embedded operating system and its routing algorithm. To validate the technological platform and the embedded operating system, two different routing strategies were compared: hierarchical and flat. Both of these routing algorithms were tested in a small-scale network applied to a watermelon field. However, we strongly believe that this technological platform can be also applied to precision agriculture because it incorporates a modified version of LORA-CBF, a wireless location-based routing algorithm that uses cluster-based flooding. Cluster-based flooding addresses the scalability concerns of wireless sensor networks, while the modified LORA-CBF routing algorithm includes a metric to monitor residual battery energy. Furthermore, results show that the modified version of LORA-CBF functions well with both the flat and hierarchical algorithms, although it functions better with the flat algorithm in a small-scale agricultural network. PMID:22346622

  3. Launching a Wireless Laptop Program

    ERIC Educational Resources Information Center

    Grignano, Domenic

    2007-01-01

    In this article, the author, as a technology director for East Rock Magnet School in New Haven, Connecticut, a federal government test site for laptop learning, shares his secrets to a successful implementation of a wireless laptop program: (1) Build a wireless foundation; (2) Do not choose the cheapest model just because of budget; (3) A sturdy…

  4. Unpowered wireless ultrasound tomography system

    NASA Astrophysics Data System (ADS)

    Zahedi, Farshad; Huang, Haiying

    2016-04-01

    In this paper, an unpowered wireless ultrasound tomography system is presented. The system consists of two subsystems; the wireless interrogation unit (WIU) and three wireless nodes installed on the structure. Each node is designed to work in generation and sensing modes, but operates at a specific microwave frequency. Wireless transmission of the ultrasound signals between the WIU and the wireless nodes is achieved by converting ultrasound signals to microwave signals and vice versa, using a microwave carrier signal. In the generation mode, both a carrier signal and an ultrasound modulated microwave signal are transmitted to the sensor nodes. Only the node whose operating frequency matches the carrier signal will receive these signals and demodulate them to recover the original ultrasound signal. In the sensing mode, a microwave carrier signal with two different frequency components matching the operating frequencies of the sensor nodes is broadcasted by the WIU. The sensor nodes, in turn, receive the corresponding carrier signals, modulate it with the ultrasound sensing signal, and wirelessly transmit the modulated signal back to the WIU. The demodulation of the sensing signals is performed in the WIU using a digital signal processing. Implementing a software receiver significantly reduces the complexity and the cost of the WIU. A wireless ultrasound tomography system is realized by interchanging the carrier frequencies so that the wireless transducers can take turn to serve as the actuator and sensors.

  5. Feasibility Study of a HOM IOT for TESLA

    NASA Astrophysics Data System (ADS)

    Schütt, Petra; Weiland, Thomas; Gamp, Alexander; Lu, Fuhai

    1997-05-01

    For the TESLA linear collider 1.3 GHz RF sources with 10 MW peak power and about 70% efficiency are needed. As an alternative to the development of a Multibeam-Klystron, we investigate the feasibility of an IOT (Inductive Output Tube). This is a very compact RF source: The time structure of the beam is produced by a gated emission cathode and the output cavity is directly adjacent to the anode. Unlike IOTs, conventional klystrons lose some of their design efficiency when they are operated below saturation, because only the RF component of the beam is reduced and not the DC beam current. In contrast to this the cathode current of an IOT is controlled by the drive power. In order to keep the gun voltage low, we investigate a device with a hollow beam where the output cavity is excited in a higher order mode (HOM), as was recently suggested by CPI(E.Lien, H.Bohlen, US Patent Application Serial No. 08/413,034). Computer simulations are carried out with the CAD-system MAFIA. First, an existing Klystrode TM IOT built by CPI is analysed. Simulation results will be shown and compared to experimental data. Based upon this experience, a design strategy is discussed for the HOM IOT.

  6. A Passively-Suspended Tesla Pump Left Ventricular Assist Device

    PubMed Central

    Izraelev, Valentin; Weiss, William J.; Fritz, Bryan; Newswanger, Raymond K.; Paterson, Eric G.; Snyder, Alan; Medvitz, Richard B.; Cysyk, Joshua; Pae, Walter E.; Hicks, Dennis; Lukic, Branka; Rosenberg, Gerson

    2009-01-01

    The design and initial test results of a new passively suspended Tesla type LAVD blood pump are described. CFD analysis was used in the design of the pump. Overall size of the prototype device is 50 mm in diameter and 75 mm in length. The pump rotor has a density lower than that of blood and when spinning inside the stator in blood it creates a buoyant centering force that suspends the rotor in the radial direction. The axial magnetic force between the rotor and stator restrain the rotor in the axial direction. The pump is capable of pumping up to 10 liters/min at a 70 mmHg head rise at 8000 RPM. The pump has demonstrated a normalized index of hemolysis level below .02 mg/dL for flows between 2 and 9.7 L/min. An inlet pressure sensor has also been incorporated into the inlet cannula wall and will be used for control purposes. One initial in vivo study showed an encouraging result. Further CFD modeling refinements are planned as well as endurance testing of the device. PMID:19770799

  7. Design and prototype fabrication of a 30 tesla cryogenic magnet

    NASA Technical Reports Server (NTRS)

    Prok, G. M.; Swanson, M. C.; Brown, G. V.

    1977-01-01

    A liquid-neon-cooled magnet has been designed to produce 30 teslas in steady operation. Its feasibility was established by a previously reported parametric study. To ensure the correctness of the heat transfer relationships used, supercritical neon heat transfer tests were made. Other tests made before the final design included tests on the effect of the magnetic field on pump motors; tensile-shear tests on the cryogenic adhesives; and simulated flow studies for the coolant. The magnet will be made of two pairs of coils, cooled by forced convection of supercritical neon. Heat from the supercritical neon will be rejected through heat exchangers which are made of roll-bonded copper panels and are submerged in a pool of saturated liquid neon. A partial mock-up coil was wound to identify the tooling required to wind the magnet. This was followed by winding a prototype pair of coils. The prototype winding established procedures for fabricating the final magnet and revealed slight changes needed in the final design.

  8. Cascading Tesla Oscillating Flow Diode for Stirling Engine Gas Bearings

    NASA Technical Reports Server (NTRS)

    Dyson, Rodger

    2012-01-01

    Replacing the mechanical check-valve in a Stirling engine with a micromachined, non-moving-part flow diode eliminates moving parts and reduces the risk of microparticle clogging. At very small scales, helium gas has sufficient mass momentum that it can act as a flow controller in a similar way as a transistor can redirect electrical signals with a smaller bias signal. The innovation here forces helium gas to flow in predominantly one direction by offering a clear, straight-path microchannel in one direction of flow, but then through a sophisticated geometry, the reversed flow is forced through a tortuous path. This redirection is achieved by using microfluid channel flow to force the much larger main flow into this tortuous path. While microdiodes have been developed in the past, this innovation cascades Tesla diodes to create a much higher pressure in the gas bearing supply plenum. In addition, the special shape of the leaves captures loose particles that would otherwise clog the microchannel of the gas bearing pads.

  9. Views of wireless network systems.

    SciTech Connect

    Young, William Frederick; Duggan, David Patrick

    2003-10-01

    Wireless networking is becoming a common element of industrial, corporate, and home networks. Commercial wireless network systems have become reliable, while the cost of these solutions has become more affordable than equivalent wired network solutions. The security risks of wireless systems are higher than wired and have not been studied in depth. This report starts to bring together information on wireless architectures and their connection to wired networks. We detail information contained on the many different views of a wireless network system. The method of using multiple views of a system to assist in the determination of vulnerabilities comes from the Information Design Assurance Red Team (IDART{trademark}) Methodology of system analysis developed at Sandia National Laboratories.

  10. 78 FR 20628 - Wireless Metering Challenge

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-05

    ... of Energy Efficiency and Renewable Energy Wireless Metering Challenge AGENCY: Office of Energy... (EERE) requests comments on the draft version of the Wireless Power Meter Challenge Specification. This... development of new technologies in the wireless electric metering space. DATES: Comments on the Wireless...

  11. Wireless Technology in K-12 Education

    ERIC Educational Resources Information Center

    Walery, Darrell

    2004-01-01

    Many schools begin implementing wireless technology slowly by creating wireless "hotspots" on the fly. This is accomplished by putting a wireless access point on a cart along with a set of wireless laptop computers. A teacher can then wheel the cart anywhere in the school that has a network drop, plug the access point in and have an instant…

  12. Dynamics of hierarchical Brownian oscillators

    NASA Astrophysics Data System (ADS)

    Knapp, E. W.

    1988-11-01

    Two hierarchical Brownian oscillator models are introduced by using a discretized Brownian oscillator model. The dynamical behavior of these models is solved exactly. Closed-form expressions for the intermediate scattering function and the energy relaxation function governing the frequency-dependent specific heat are given. A general relationship between the two relaxation functions is established. The case of a rectangular distribution of activation energies for the different hierarchy levels of the oscillator is considered in more detail. There the energy relaxation function decays with a logarithmic slope and the intermediate scattering function exhibits an algebraic long-time decay. The two hierarchical Brownian oscillator models have the same dynamical behavior though they possess a quite different coupling scheme.

  13. Parallel hierarchical method in networks

    NASA Astrophysics Data System (ADS)

    Malinochka, Olha; Tymchenko, Leonid

    2007-09-01

    This method of parallel-hierarchical Q-transformation offers new approach to the creation of computing medium - of parallel -hierarchical (PH) networks, being investigated in the form of model of neurolike scheme of data processing [1-5]. The approach has a number of advantages as compared with other methods of formation of neurolike media (for example, already known methods of formation of artificial neural networks). The main advantage of the approach is the usage of multilevel parallel interaction dynamics of information signals at different hierarchy levels of computer networks, that enables to use such known natural features of computations organization as: topographic nature of mapping, simultaneity (parallelism) of signals operation, inlaid cortex, structure, rough hierarchy of the cortex, spatially correlated in time mechanism of perception and training [5].

  14. Hierarchical Bayesian inverse reinforcement learning.

    PubMed

    Choi, Jaedeug; Kim, Kee-Eung

    2015-04-01

    Inverse reinforcement learning (IRL) is the problem of inferring the underlying reward function from the expert's behavior data. The difficulty in IRL mainly arises in choosing the best reward function since there are typically an infinite number of reward functions that yield the given behavior data as optimal. Another difficulty comes from the noisy behavior data due to sub-optimal experts. We propose a hierarchical Bayesian framework, which subsumes most of the previous IRL algorithms as well as models the sub-optimality of the expert's behavior. Using a number of experiments on a synthetic problem, we demonstrate the effectiveness of our approach including the robustness of our hierarchical Bayesian framework to the sub-optimal expert behavior data. Using a real dataset from taxi GPS traces, we additionally show that our approach predicts the driving behavior with a high accuracy. PMID:25291805

  15. Topological properties of hierarchical networks

    NASA Astrophysics Data System (ADS)

    Agliari, Elena; Barra, Adriano; Galluzzi, Andrea; Guerra, Francesco; Tantari, Daniele; Tavani, Flavia

    2015-06-01

    Hierarchical networks are attracting a renewal interest for modeling the organization of a number of biological systems and for tackling the complexity of statistical mechanical models beyond mean-field limitations. Here we consider the Dyson hierarchical construction for ferromagnets, neural networks, and spin glasses, recently analyzed from a statistical-mechanics perspective, and we focus on the topological properties of the underlying structures. In particular, we find that such structures are weighted graphs that exhibit a high degree of clustering and of modularity, with a small spectral gap; the robustness of such features with respect to the presence of thermal noise is also studied. These outcomes are then discussed and related to the statistical-mechanics scenario in full consistency. Last, we look at these weighted graphs as Markov chains and we show that in the limit of infinite size, the emergence of ergodicity breakdown for the stochastic process mirrors the emergence of metastabilities in the corresponding statistical mechanical analysis.

  16. Multicast Routing of Hierarchical Data

    NASA Technical Reports Server (NTRS)

    Shacham, Nachum

    1992-01-01

    The issue of multicast of broadband, real-time data in a heterogeneous environment, in which the data recipients differ in their reception abilities, is considered. Traditional multicast schemes, which are designed to deliver all the source data to all recipients, offer limited performance in such an environment, since they must either force the source to overcompress its signal or restrict the destination population to those who can receive the full signal. We present an approach for resolving this issue by combining hierarchical source coding techniques, which allow recipients to trade off reception bandwidth for signal quality, and sophisticated routing algorithms that deliver to each destination the maximum possible signal quality. The field of hierarchical coding is briefly surveyed and new multicast routing algorithms are presented. The algorithms are compared in terms of network utilization efficiency, lengths of paths, and the required mechanisms for forwarding packets on the resulting paths.

  17. Hierarchical structure of biological systems

    PubMed Central

    Alcocer-Cuarón, Carlos; Rivera, Ana L; Castaño, Victor M

    2014-01-01

    A general theory of biological systems, based on few fundamental propositions, allows a generalization of both Wierner and Berthalanffy approaches to theoretical biology. Here, a biological system is defined as a set of self-organized, differentiated elements that interact pair-wise through various networks and media, isolated from other sets by boundaries. Their relation to other systems can be described as a closed loop in a steady-state, which leads to a hierarchical structure and functioning of the biological system. Our thermodynamical approach of hierarchical character can be applied to biological systems of varying sizes through some general principles, based on the exchange of energy information and/or mass from and within the systems. PMID:24145961

  18. Hierarchical Molecular Modelling with Ellipsoids

    SciTech Connect

    Max, N

    2004-03-29

    Protein and DNA structures are represented at varying levels of details using ellipsoidal RGBA textured splats. The splat texture at each level is generated by rendering its children in a hierarchical model, from a distribution of viewing directions, and averaging the result. For rendering, the ellipsoids to be used are chosen adaptively, depending on the distance to the viewpoint. This technique is applied to visualize DNA coiling around nucleosomes in chromosomes.

  19. A wireless ballistocardiographic chair.

    PubMed

    Junnila, Sakari; Akhbardeh, Alireza; Barna, Laurentiu C; Defee, Irek; Varri, Alpo

    2006-01-01

    This paper presents a wireless ballistocardiographic chair developed for the Proactive Health Monitoring project in the Institute of Signal Processing. EMFi sensors are used for BCG measurement and IEEE 802.15.4 RF link for radio communication between the chair and a PC. The chair measures two BCG signals from the seat and the backrest and a rough ECG signal from the armrests of the chair. The R-spike of the ECG signal can be used as a synchronisation point to extract individual BCG cardiac cycles. Also, two developed methods for extracting BCG cycles without using a reference ECG signal are presented and compared. PMID:17946348

  20. Deployable wireless Fresnel lens

    NASA Technical Reports Server (NTRS)

    Kennedy, Timothy F. (Inventor); Fink, Patrick W. (Inventor); Chu, Andrew W. (Inventor); Lin, Gregory Y. (Inventor)

    2013-01-01

    Apparatus and methods for enhancing the gain of a wireless signal are provided. In at least one specific embodiment, the apparatus can include a screen comprised of one or more electrically conductive regions for reflecting electromagnetic radiation and one or more non-conductive regions for permitting electromagnetic radiation therethrough. The one or more electrically conductive regions can be disposed adjacent to at least one of the one or more non-conductive regions. The apparatus can also include a support member disposed about at least a portion of the screen. The screen can be capable of collapsing by twisting the support member in opposite screw senses to form interleaved concentric sections.

  1. Wireless Headset Communication System

    NASA Technical Reports Server (NTRS)

    Lau, Wilfred K.; Swanson, Richard; Christensen, Kurt K.

    1995-01-01

    System combines features of pagers, walkie-talkies, and cordless telephones. Wireless headset communication system uses digital modulation on spread spectrum to avoid interference among units. Consists of base station, 4 radio/antenna modules, and as many as 16 remote units with headsets. Base station serves as network controller, audio-mixing network, and interface to such outside services as computers, telephone networks, and other base stations. Developed for use at Kennedy Space Center, system also useful in industrial maintenance, emergency operations, construction, and airport operations. Also, digital capabilities exploited; by adding bar-code readers for use in taking inventories.

  2. Wireless passive radiation sensor

    SciTech Connect

    Pfeifer, Kent B; Rumpf, Arthur N; Yelton, William G; Limmer, Steven J

    2013-12-03

    A novel measurement technique is employed using surface acoustic wave (SAW) devices, passive RF, and radiation-sensitive films to provide a wireless passive radiation sensor that requires no batteries, outside wiring, or regular maintenance. The sensor is small (<1 cm.sup.2), physically robust, and will operate unattended for decades. In addition, the sensor can be insensitive to measurement position and read distance due to a novel self-referencing technique eliminating the need to measure absolute responses that are dependent on RF transmitter location and power.

  3. Prospective Real Time Head Motion Correction Using Inductively Coupled Wireless NMR Probes

    PubMed Central

    Sengupta, Saikat; Tadanki, Sasidhar; Gore, John C.; Welch, E. Brian

    2014-01-01

    Purpose Head motion continues to be a major source of artifacts and data quality degradation in MRI. The goal of this work was to develop and demonstrate a novel technique for prospective, 6 degrees of freedom (6DOF) rigid body motion estimation and real time motion correction using inductively coupled wireless nuclear magnetic resonance (NMR) probe markers. Methods Three wireless probes that are inductively coupled with the scanner’s RF setup serve as fiducials on the subject’s head. A 12 ms linear navigator module is interleaved with the imaging sequence for head position estimation, and scan geometry is updated in real time for motion compensation. Flip angle amplification in the markers allows the use of extremely small navigator flip angles (~1°). A novel algorithm is presented to identify marker positions in the absence of marker specific receive channels. The method is demonstrated for motion correction in 1 mm3 gradient recalled echo experiments in phantoms and humans. Results Significant improvement of image quality is demonstrated in phantoms and human volunteers under different motion conditions. Conclusion A novel real time 6 DOF head motion correction technique based on wireless NMR probes is demonstrated in high resolution imaging at 7 Tesla. PMID:24243810

  4. High power Tesla driven miniature plasma opening switch

    NASA Astrophysics Data System (ADS)

    Kumar, Rajesh

    The plasma opening switch (POS) is used in pulsed power systems where a very fast opening and high current switch is required. Plasma is injected into the switch, which carries a large conduction current, before it opens in a process that lasts for a few nanosecond and transfers the current to a parallel-connected load at a much increased voltage and with a much shorter rise time. The conduction and opening times of the switch are dependent on plasma parameters such as the distribution, speed and species, all of which are determined by the plasma source. Most of the earlier reported work involves large dimension POSs and a correspondingly high input current (more than 100 kA) and uses carbon plasma. One main objective of the present research was to achieve a low input current (20 kA) and miniaturised POS by using hydrogen plasma rather than carbon plasma on account of its lower mass. A cable gun was selected for producing the plasma, since although this produces both hydrogen and carbon plasma these arise different times during its operation.. For the present application a Tesla transformer was used in preference to a Marx generator to produce an initial high voltage pulse for the system, on the basis of its simpler design and cost effectiveness. This transformer together with an associated water PFL (pulse forming line) and pressurised switch was capable of producing a load current in excess of 20 kA with a rise time of 53 ns, which was fed through the POS to the final load. Special diagnostics arrangements were necessary to measure the fast high current and voltage pulse a in nonintrusive way. Faraday cups and a high speed camera were used to measure the plasma parameters. The overall system built (i.e. including the POS) is capable of producing a 22 kA current with a rise time of 5 ns, and of generating a power of more than 10 GW..

  5. Household wireless electroencephalogram hat

    NASA Astrophysics Data System (ADS)

    Szu, Harold; Hsu, Charles; Moon, Gyu; Yamakawa, Takeshi; Tran, Binh

    2012-06-01

    We applied Compressive Sensing to design an affordable, convenient Brain Machine Interface (BMI) measuring the high spatial density, and real-time process of Electroencephalogram (EEG) brainwaves by a Smartphone. It is useful for therapeutic and mental health monitoring, learning disability biofeedback, handicap interfaces, and war gaming. Its spec is adequate for a biomedical laboratory, without the cables hanging over the head and tethered to a fixed computer terminal. Our improved the intrinsic signal to noise ratio (SNR) by using the non-uniform placement of the measuring electrodes to create the proximity of measurement to the source effect. We computing a spatiotemporal average the larger magnitude of EEG data centers in 0.3 second taking on tethered laboratory data, using fuzzy logic, and computing the inside brainwave sources, by Independent Component Analysis (ICA). Consequently, we can overlay them together by non-uniform electrode distribution enhancing the signal noise ratio and therefore the degree of sparseness by threshold. We overcame the conflicting requirements between a high spatial electrode density and precise temporal resolution (beyond Event Related Potential (ERP) P300 brainwave at 0.3 sec), and Smartphone wireless bottleneck of spatiotemporal throughput rate. Our main contribution in this paper is the quality and the speed of iterative compressed image recovery algorithm based on a Block Sparse Code (Baranuick et al, IEEE/IT 2008). As a result, we achieved real-time wireless dynamic measurement of EEG brainwaves, matching well with traditionally tethered high density EEG.

  6. Biomonitoring with Wireless Communications

    SciTech Connect

    Budinger, Thomas F.

    2003-03-01

    This review is divided into three sections: technologies for monitoring physiological parameters; biosensors for chemical assays and wireless communications technologies including image transmissions. Applications range from monitoring high risk patients for heart, respiratory activity and falls to sensing levels of physical activity in military, rescue, and sports personnel. The range of measurements include, heart rate, pulse wave form, respiratory rate, blood oxygen, tissue pCO2, exhaled carbon dioxide and physical activity. Other feasible measurements will employ miniature chemical laboratories on silicon or plastic chips. The measurements can be extended to clinical chemical assays ranging from common blood assays to protein or specialized protein measurements (e.g., troponin, creatine, and cytokines such as TNF and IL6). Though the feasibility of using wireless technology to communicate vital signs has been demonstrated 32 years ago (1) it has been only recently that practical and portable devices and communications net works have become generally available for inexpensive deployment of comfortable and affordable devices and systems.

  7. Smart programmable wireless microaccelerometers

    NASA Astrophysics Data System (ADS)

    Varadan, Vijay K.; Subramanian, Hareesh; Varadan, Vasundara V.

    1998-07-01

    The integration of MEMS, SAW devices and required microelectronics and conformal antenna to realize a programmable wireless accelerometer is presented in this paper. This unique combination of technologies results in a novel accelerometer that can be remotely sensed by a microwave system with the advantage of no power requirements at the sensor site. The microaccelerometer presented is simple in construction and easy to manufacture with existing silicon micromachining techniques. Programmable accelerometers can be achieved with splitfinger interdigital transducers (IDTs) as reflecting structures. If IDTs are short circuited or capacitively loaded, the wave propagates without any reflection whereas in an open circuit configuration, the IDTs reflect the incoming SAW signal. The programmable accelerometers can thus be achieved by using an external circuitry on a semiconductor chip using hybrid technology. The relatively small size of the sensor makes it an ideal conformal sensor. The accelerometer finds application as air bag deployment sensors, vibration sensors for noise control, deflection and strain sensors, inertial and dimensional positioning systems, ABS/traction control, smart suspension, active roll stabilization and four wheel steering. The wireless accelerometer is very attractive to study the response of a `dummy' in automobile crash test.

  8. Radio Relays Improve Wireless Products

    NASA Technical Reports Server (NTRS)

    2009-01-01

    Signal Hill, California-based XCOM Wireless Inc. developed radio frequency micromachine (RF MEMS) relays with a Phase II Small Business Innovation Research (SBIR) contract through NASA?s Jet Propulsion Laboratory. In order to improve satellite communication systems, XCOM produced wireless RF MEMS relays and tunable capacitors that use metal-to-metal contact and have the potential to outperform most semiconductor technologies while using less power. These relays are used in high-frequency test equipment and instrumentation, where increased speed can mean significant cost savings. Applications now also include mainstream wireless applications and greatly improved tactical radios.

  9. Wireless Communications in Smart Grid

    NASA Astrophysics Data System (ADS)

    Bojkovic, Zoran; Bakmaz, Bojan

    Communication networks play a crucial role in smart grid, as the intelligence of this complex system is built based on information exchange across the power grid. Wireless communications and networking are among the most economical ways to build the essential part of the scalable communication infrastructure for smart grid. In particular, wireless networks will be deployed widely in the smart grid for automatic meter reading, remote system and customer site monitoring, as well as equipment fault diagnosing. With an increasing interest from both the academic and industrial communities, this chapter systematically investigates recent advances in wireless communication technology for the smart grid.

  10. Wireless device monitoring methods, wireless device monitoring systems, and articles of manufacture

    DOEpatents

    McCown, Steven H.; Derr, Kurt W.; Rohde, Kenneth W.

    2012-05-08

    Wireless device monitoring methods, wireless device monitoring systems, and articles of manufacture are described. According to one embodiment, a wireless device monitoring method includes accessing device configuration information of a wireless device present at a secure area, wherein the device configuration information comprises information regarding a configuration of the wireless device, accessing stored information corresponding to the wireless device, wherein the stored information comprises information regarding the configuration of the wireless device, comparing the device configuration information with the stored information, and indicating the wireless device as one of authorized and unauthorized for presence at the secure area using the comparing.

  11. A survey on routing protocols for large-scale wireless sensor networks.

    PubMed

    Li, Changle; Zhang, Hanxiao; Hao, Binbin; Li, Jiandong

    2011-01-01

    With the advances in micro-electronics, wireless sensor devices have been made much smaller and more integrated, and large-scale wireless sensor networks (WSNs) based the cooperation among the significant amount of nodes have become a hot topic. "Large-scale" means mainly large area or high density of a network. Accordingly the routing protocols must scale well to the network scope extension and node density increases. A sensor node is normally energy-limited and cannot be recharged, and thus its energy consumption has a quite significant effect on the scalability of the protocol. To the best of our knowledge, currently the mainstream methods to solve the energy problem in large-scale WSNs are the hierarchical routing protocols. In a hierarchical routing protocol, all the nodes are divided into several groups with different assignment levels. The nodes within the high level are responsible for data aggregation and management work, and the low level nodes for sensing their surroundings and collecting information. The hierarchical routing protocols are proved to be more energy-efficient than flat ones in which all the nodes play the same role, especially in terms of the data aggregation and the flooding of the control packets. With focus on the hierarchical structure, in this paper we provide an insight into routing protocols designed specifically for large-scale WSNs. According to the different objectives, the protocols are generally classified based on different criteria such as control overhead reduction, energy consumption mitigation and energy balance. In order to gain a comprehensive understanding of each protocol, we highlight their innovative ideas, describe the underlying principles in detail and analyze their advantages and disadvantages. Moreover a comparison of each routing protocol is conducted to demonstrate the differences between the protocols in terms of message complexity, memory requirements, localization, data aggregation, clustering manner and

  12. A Survey on Routing Protocols for Large-Scale Wireless Sensor Networks

    PubMed Central

    Li, Changle; Zhang, Hanxiao; Hao, Binbin; Li, Jiandong

    2011-01-01

    With the advances in micro-electronics, wireless sensor devices have been made much smaller and more integrated, and large-scale wireless sensor networks (WSNs) based the cooperation among the significant amount of nodes have become a hot topic. “Large-scale” means mainly large area or high density of a network. Accordingly the routing protocols must scale well to the network scope extension and node density increases. A sensor node is normally energy-limited and cannot be recharged, and thus its energy consumption has a quite significant effect on the scalability of the protocol. To the best of our knowledge, currently the mainstream methods to solve the energy problem in large-scale WSNs are the hierarchical routing protocols. In a hierarchical routing protocol, all the nodes are divided into several groups with different assignment levels. The nodes within the high level are responsible for data aggregation and management work, and the low level nodes for sensing their surroundings and collecting information. The hierarchical routing protocols are proved to be more energy-efficient than flat ones in which all the nodes play the same role, especially in terms of the data aggregation and the flooding of the control packets. With focus on the hierarchical structure, in this paper we provide an insight into routing protocols designed specifically for large-scale WSNs. According to the different objectives, the protocols are generally classified based on different criteria such as control overhead reduction, energy consumption mitigation and energy balance. In order to gain a comprehensive understanding of each protocol, we highlight their innovative ideas, describe the underlying principles in detail and analyze their advantages and disadvantages. Moreover a comparison of each routing protocol is conducted to demonstrate the differences between the protocols in terms of message complexity, memory requirements, localization, data aggregation, clustering manner

  13. Entropy bounds for hierarchical molecular networks.

    PubMed

    Dehmer, Matthias; Borgert, Stephan; Emmert-Streib, Frank

    2008-01-01

    In this paper we derive entropy bounds for hierarchical networks. More precisely, starting from a recently introduced measure to determine the topological entropy of non-hierarchical networks, we provide bounds for estimating the entropy of hierarchical graphs. Apart from bounds to estimate the entropy of a single hierarchical graph, we see that the derived bounds can also be used for characterizing graph classes. Our contribution is an important extension to previous results about the entropy of non-hierarchical networks because for practical applications hierarchical networks are playing an important role in chemistry and biology. In addition to the derivation of the entropy bounds, we provide a numerical analysis for two special graph classes, rooted trees and generalized trees, and demonstrate hereby not only the computational feasibility of our method but also learn about its characteristics and interpretability with respect to data analysis. PMID:18769487

  14. Ultrasonic wireless health monitoring

    NASA Astrophysics Data System (ADS)

    Petit, Lionel; Lefeuvre, Elie; Guyomar, Daniel; Richard, Claude; Guy, Philippe; Yuse, Kaori; Monnier, Thomas

    2006-03-01

    The integration of autonomous wireless elements in health monitoring network increases the reliability by suppressing power supplies and data transmission wiring. Micro-power piezoelectric generators are an attractive alternative to primary batteries which are limited by a finite amount of energy, a limited capacity retention and a short shelf life (few years). Our goal is to implement such an energy harvesting system for powering a single AWT (Autonomous Wireless Transmitter) using our SSH (Synchronized Switch Harvesting) method. Based on a non linear process of the piezoelement voltage, this SSH method optimizes the energy extraction from the mechanical vibrations. This AWT has two main functions : The generation of an identifier code by RF transmission to the central receiver and the Lamb wave generation for the health monitoring of the host structure. A damage index is derived from the variation between the transmitted wave spectrum and a reference spectrum. The same piezoelements are used for the energy harvesting function and the Lamb wave generation, thus reducing mass and cost. A micro-controller drives the energy balance and synchronizes the functions. Such an autonomous transmitter has been evaluated on a 300x50x2 mm 3 composite cantilever beam. Four 33x11x0.3 mm 3 piezoelements are used for the energy harvesting and for the wave lamb generation. A piezoelectric sensor is placed at the free end of the beam to track the transmitted Lamb wave. In this configuration, the needed energy for the RF emission is 0.1 mJ for a 1 byte-information and the Lamb wave emission requires less than 0.1mJ. The AWT can harvested an energy quantity of approximately 20 mJ (for a 1.5 Mpa lateral stress) with a 470 μF storage capacitor. This corresponds to a power density near to 6mW/cm 3. The experimental AWT energy abilities are presented and the damage detection process is discussed. Finally, some envisaged solutions are introduced for the implementation of the required data

  15. Some physical applications of random hierarchical matrices

    SciTech Connect

    Avetisov, V. A.; Bikulov, A. Kh.; Vasilyev, O. A.; Nechaev, S. K.; Chertovich, A. V.

    2009-09-15

    The investigation of spectral properties of random block-hierarchical matrices as applied to dynamic and structural characteristics of complex hierarchical systems with disorder is proposed for the first time. Peculiarities of dynamics on random ultrametric energy landscapes are discussed and the statistical properties of scale-free and polyscale (depending on the topological characteristics under investigation) random hierarchical networks (graphs) obtained by multiple mapping are considered.

  16. Note: Tesla based pulse generator for electrical breakdown study of liquid dielectrics

    NASA Astrophysics Data System (ADS)

    Veda Prakash, G.; Kumar, R.; Patel, J.; Saurabh, K.; Shyam, A.

    2013-12-01

    In the process of studying charge holding capability and delay time for breakdown in liquids under nanosecond (ns) time scales, a Tesla based pulse generator has been developed. Pulse generator is a combination of Tesla transformer, pulse forming line, a fast closing switch, and test chamber. Use of Tesla transformer over conventional Marx generators makes the pulse generator very compact, cost effective, and requires less maintenance. The system has been designed and developed to deliver maximum output voltage of 300 kV and rise time of the order of tens of nanoseconds. The paper deals with the system design parameters, breakdown test procedure, and various experimental results. To validate the pulse generator performance, experimental results have been compared with PSPICE simulation software and are in good agreement with simulation results.

  17. Simple RF design for human functional and morphological cardiac imaging at 7 tesla

    NASA Astrophysics Data System (ADS)

    Versluis, M. J.; Tsekos, N.; Smith, N. B.; Webb, A. G.

    2009-09-01

    Morphological and functional cardiac MRI can potentially benefit greatly from the recent advent of commercial high-field (7 tesla and above) MRI systems. However, conventional hardware configurations at lower field using a body-coil for homogeneous transmission are not available at these field strengths. Sophisticated multiple-transmit-channel systems have been shown to be able to image the human heart at 7 tesla but such systems are currently not widely available. In this paper, we empirically optimize the design of a simple quadrature coil for cardiac imaging at 7 tesla. The size, geometry, and position have been chosen to produce a B1 field with no tissue-induced signal voids within the heart. Standard navigator echoes for gating were adapted for operation at the heart/lung interface, directly along the head-foot direction. Using this setup, conventional and high-resolution cine functional imaging have been successfully performed, as has morphological imaging of the right coronary artery.

  18. Note: Tesla based pulse generator for electrical breakdown study of liquid dielectrics.

    PubMed

    Veda Prakash, G; Kumar, R; Patel, J; Saurabh, K; Shyam, A

    2013-12-01

    In the process of studying charge holding capability and delay time for breakdown in liquids under nanosecond (ns) time scales, a Tesla based pulse generator has been developed. Pulse generator is a combination of Tesla transformer, pulse forming line, a fast closing switch, and test chamber. Use of Tesla transformer over conventional Marx generators makes the pulse generator very compact, cost effective, and requires less maintenance. The system has been designed and developed to deliver maximum output voltage of 300 kV and rise time of the order of tens of nanoseconds. The paper deals with the system design parameters, breakdown test procedure, and various experimental results. To validate the pulse generator performance, experimental results have been compared with PSPICE simulation software and are in good agreement with simulation results. PMID:24387484

  19. Liquid neon heat transfer as applied to a 30 tesla cryomagnet

    NASA Technical Reports Server (NTRS)

    Papell, S. S.; Hendricks, R. C.

    1975-01-01

    Since superconducting magnets cooled by liquid helium are limited to magnetic fields of about 18 teslas, the design of a 30 tesla cryomagnet necessitates forced convection liquid neon heat transfer in small coolant channels. As these channels are too small to handle the vapor flow if the coolant were to boil, the design philosophy calls for suppressing boiling by subjecting the fluid to high pressures. Forced convection heat transfer data are obtained by using a blowdown technique to force the fluid vertically through a resistance-heated instrumented tube. The data are obtained at inlet temperatures between 28 and 34 K and system pressures between 28 to 29 bars. Data correlation is limited to a very narrow range of test conditions, since the tests were designed to simulate the heat transfer characteristics in the coolant channels of the 30 tesla cryomagnet concerned. The results can therefore be applied directly to the design of the magnet system.-

  20. Interactive explorations of hierarchical segmentations

    NASA Technical Reports Server (NTRS)

    Tilton, James C.

    1992-01-01

    The authors report on the implementation of an interactive tool, called HSEGEXP, to interactively explore the hierarchical segmentation produced by the iterative parallel region growing (IPRG) algorithm to select the best segmentation result. This combination of the HSEGEXP tool with the IPRG algorithm amounts to a computer-assisted image segmentation system guided by human interaction. The initial application of the HSEGEXP tool is in the refinement of ground reference data based on the IPRG/HSEGEXP segmentation of the corresponding remotely sensed image data. The HSEGEXP tool is being used to help evaluate the effectiveness of an automatic 'best' segmentation process under development.

  1. Hierarchical clustering using mutual information

    NASA Astrophysics Data System (ADS)

    Kraskov, A.; Stögbauer, H.; Andrzejak, R. G.; Grassberger, P.

    2005-04-01

    We present a conceptually simple method for hierarchical clustering of data called mutual information clustering (MIC) algorithm. It uses mutual information (MI) as a similarity measure and exploits its grouping property: The MI between three objects X, Y, and Z is equal to the sum of the MI between X and Y, plus the MI between Z and the combined object (XY). We use this both in the Shannon (probabilistic) version of information theory and in the Kolmogorov (algorithmic) version. We apply our method to the construction of phylogenetic trees from mitochondrial DNA sequences and to the output of independent components analysis (ICA) as illustrated with the ECG of a pregnant woman.

  2. Wireless Damage Location Sensing System

    NASA Technical Reports Server (NTRS)

    Woodard, Stanley E. (Inventor); Taylor, Bryant Douglas (Inventor)

    2012-01-01

    A wireless damage location sensing system uses a geometric-patterned wireless sensor that resonates in the presence of a time-varying magnetic field to generate a harmonic response that will experience a change when the sensor experiences a change in its geometric pattern. The sensing system also includes a magnetic field response recorder for wirelessly transmitting the time-varying magnetic field and for wirelessly detecting the harmonic response. The sensing system compares the actual harmonic response to a plurality of predetermined harmonic responses. Each predetermined harmonic response is associated with a severing of the sensor at a corresponding known location thereof so that a match between the actual harmonic response and one of the predetermined harmonic responses defines the known location of the severing that is associated therewith.

  3. Wireless Josephson amplifier

    SciTech Connect

    Narla, A.; Sliwa, K. M.; Hatridge, M.; Shankar, S.; Frunzio, L.; Schoelkopf, R. J.; Devoret, M. H.

    2014-06-09

    Josephson junction parametric amplifiers are playing a crucial role in the readout chain in superconducting quantum information experiments. However, their integration with current 3D cavity implementations poses the problem of transitioning between waveguide, coax cables, and planar circuits. Moreover, Josephson amplifiers require auxiliary microwave components, like directional couplers and/or hybrids, that are sources of spurious losses and impedance mismatches that limit measurement efficiency and amplifier tunability. We have developed a wireless architecture for these parametric amplifiers that eliminates superfluous microwave components and interconnects. This greatly simplifies their assembly and integration into experiments. We present an experimental realization of such a device operating in the 9–11 GHz band with about 100 MHz of amplitude gain-bandwidth product, on par with devices mounted in conventional sample holders. The simpler impedance environment presented to the amplifier also results in increased amplifier tunability.

  4. Wireless Josephson Junction Arrays

    NASA Astrophysics Data System (ADS)

    Adams, Laura

    2015-03-01

    We report low temperature, microwave transmission measurements on a wireless two- dimensional network of Josephson junction arrays composed of superconductor-insulator -superconductor tunnel junctions. Unlike their biased counterparts, by removing all electrical contacts to the arrays and superfluous microwave components and interconnects in the transmission line, we observe new collective behavior in the transmission spectra. In particular we will show emergent behavior that systematically responds to changes in microwave power at fixed temperature. Likewise we will show the dynamic and collective response of the arrays while tuning the temperature at fixed microwave power. We discuss these spectra in terms of the Berezinskii-Kosterlitz-Thouless phase transition and Shapiro steps. We gratefully acknowledge the support Prof. Steven Anlage at the University of Maryland and Prof. Allen Goldman at the University of Minnesota. Physics and School of Engineering and Applied Sciences.

  5. Wireless power transfer system

    DOEpatents

    Wu, Hunter; Sealy, Kylee; Gilchrist, Aaron

    2016-02-23

    A system includes a first stage of an inductive power transfer system with an LCL load resonant converter with a switching section, an LCL tuning circuit, and a primary receiver pad. The IPT system includes a second stage with a secondary receiver pad, a secondary resonant circuit, a secondary rectification circuit, and a secondary decoupling converter. The secondary receiver pad connects to the secondary resonant circuit. The secondary resonant circuit connects to the secondary rectification circuit. The secondary rectification circuit connects to the secondary decoupling converter. The second stage connects to a load. The load includes an energy storage element. The second stage and load are located on a vehicle and the first stage is located at a fixed location. The primary receiver pad wirelessly transfers power to the secondary receiver pad across a gap when the vehicle positions the secondary receiver pad with respect to the primary receiver pad.

  6. WIRELESS MINE WIDE TELECOMMUNICATIONS TECHNOLOGY

    SciTech Connect

    Zvi H. Meiksin

    2002-04-01

    Two industrial prototype units for through-the-earth wireless communication were constructed and tested. Preparation for a temporary installation in NIOSH's Lake Lynn mine for the through-the-earth and the in-mine system were completed. Progress was made in the programming of the in-mine system to provide data communication. Work has begun to implement a wireless interface between equipment controllers and our in-mine system.

  7. Wireless Power Transfer

    SciTech Connect

    2013-07-22

    Wireless Power Transfer is an innovative approach using magnetic resonance coupling of air core transformers designed for today's growing plug-in electric vehicle market. This technology can provide a convenient, safe and flexible means to charge electric vehicles under stationary and dynamic conditions. Plug-in Electric Vehicles (PEV) are burdened by the need for cable and plug charger, galvanic isolation of the on-board electronics, bulk and cost of this charger and the large energy storage system (ESS) packs needed. With a system where you have to physically plug in there are a number of occasions where the owner could very well forget to charge the vehicle. For stationary applications (like charging of a PHEV at home), ORNL's innovative wireless power transfer technology adds a convenience factor compared to actually plugging in which will mean that the vehicle will have a full charge every morning. Electric vehicle charging must be safe, compact and efficient in order to be convenient for customers. By reconfiguring the transformer and altering the resonance frequency, energy is transferred to the battery with lower energy losses and with fewer demands on the primary circuit by the rest of the transformer system. The ORNL discovery shows that sufficient power for the battery can be transferred from the primary to secondary circuits without significant energy losses if the operating frequency is set at 50% to 95% of the resonance frequency of the circuit. The electrical power is then transmitted to the chargeable battery, which is electrically coupled to the secondary circuit through the air core transformer. Some advantages include: Reduced energy losses during transfer of energy to the battery; A charge potential that is relatively unaffected by up to 25% misalignment of vehicle; and Other receiving components draw less power from the primary circuit. These advantages allow wireless power technology applications to expand at the workplace and beyond as the

  8. Wireless Power Transfer

    ScienceCinema

    None

    2013-11-19

    Wireless Power Transfer is an innovative approach using magnetic resonance coupling of air core transformers designed for today's growing plug-in electric vehicle market. This technology can provide a convenient, safe and flexible means to charge electric vehicles under stationary and dynamic conditions. Plug-in Electric Vehicles (PEV) are burdened by the need for cable and plug charger, galvanic isolation of the on-board electronics, bulk and cost of this charger and the large energy storage system (ESS) packs needed. With a system where you have to physically plug in there are a number of occasions where the owner could very well forget to charge the vehicle. For stationary applications (like charging of a PHEV at home), ORNL's innovative wireless power transfer technology adds a convenience factor compared to actually plugging in which will mean that the vehicle will have a full charge every morning. Electric vehicle charging must be safe, compact and efficient in order to be convenient for customers. By reconfiguring the transformer and altering the resonance frequency, energy is transferred to the battery with lower energy losses and with fewer demands on the primary circuit by the rest of the transformer system. The ORNL discovery shows that sufficient power for the battery can be transferred from the primary to secondary circuits without significant energy losses if the operating frequency is set at 50% to 95% of the resonance frequency of the circuit. The electrical power is then transmitted to the chargeable battery, which is electrically coupled to the secondary circuit through the air core transformer. Some advantages include: Reduced energy losses during transfer of energy to the battery; A charge potential that is relatively unaffected by up to 25% misalignment of vehicle; and Other receiving components draw less power from the primary circuit. These advantages allow wireless power technology applications to expand at the workplace and beyond as the

  9. Test results of a single aperture 10 tesla dipole model magnet for the Large Hadron Collider

    SciTech Connect

    Yamamoto, Akira; Shintomi, Takakazu; Kimura, Nobuhiro

    1996-07-01

    A single aperture dipole magnet has been developed with a design magnetic field of 10 tesla by using Nb-Ti/Cu conductor to be operated at 1.8 K in pressurized super fluid helium. The magnet features double shell coil design by using high keystone Rutherford cable and compact non-magnetic steel collars to be adaptable in split/symmetric coil/collar design for twin aperture dipoles. A design central magnetic field of 10 tesla has been successfully achieved in excitation at 1.95 K in pressurized superfluid helium. Test results of the magnet with a summary of the design and fabrication will be presented.

  10. Cold- and Beam Test of the First Prototypes of the Superstructure for the TESLA Collider

    SciTech Connect

    Baboi, Nicoleta

    2003-08-08

    After three years of preparation, two superstructures, each made of two superconducting 7-cell weakly coupled subunits, have been installed in the TESLA Test Facility linac (TTF) for the cold- and beam-test. The energy stability, the HOMs damping, the frequency and the field adjustment methods were tested. The measured results confirmed expectation on the superstructure performance and proved that alternative layout for the 800 GeV upgrade of the TESLA collider, as it was proposed in TDR, is feasible. We report on the test and give here an overview of its results which are commented in more detail elsewhere in these Proceedings.

  11. Wireless Instrumentation Use on Launch Vehicles

    NASA Technical Reports Server (NTRS)

    Sherman, Aaron

    2010-01-01

    This slide presentation reviews the results of a study on the use of wireless instrumentation and sensors on future launch vehicles. The use of wireless technologies would if feasible would allow for fewer wires, and allow for more flexibility. However, it was generally concluded that wireless solutions are not currently ready to replace wired technologies for launch vehicles. The recommendations of the study were to continue to use wired sensors as the primary choice for vehicle instrumentation, and to continue to assess needs and use wireless instrumentation where appropriate. The future work includes support efforts for wireless technologies, and continue to monitor the development of wireless solutions.

  12. Dynamic Organization of Hierarchical Memories.

    PubMed

    Kurikawa, Tomoki; Kaneko, Kunihiko

    2016-01-01

    In the brain, external objects are categorized in a hierarchical way. Although it is widely accepted that objects are represented as static attractors in neural state space, this view does not take account interaction between intrinsic neural dynamics and external input, which is essential to understand how neural system responds to inputs. Indeed, structured spontaneous neural activity without external inputs is known to exist, and its relationship with evoked activities is discussed. Then, how categorical representation is embedded into the spontaneous and evoked activities has to be uncovered. To address this question, we studied bifurcation process with increasing input after hierarchically clustered associative memories are learned. We found a "dynamic categorization"; neural activity without input wanders globally over the state space including all memories. Then with the increase of input strength, diffuse representation of higher category exhibits transitions to focused ones specific to each object. The hierarchy of memories is embedded in the transition probability from one memory to another during the spontaneous dynamics. With increased input strength, neural activity wanders over a narrower state space including a smaller set of memories, showing more specific category or memory corresponding to the applied input. Moreover, such coarse-to-fine transitions are also observed temporally during transient process under constant input, which agrees with experimental findings in the temporal cortex. These results suggest the hierarchy emerging through interaction with an external input underlies hierarchy during transient process, as well as in the spontaneous activity. PMID:27618549

  13. Hierarchical classification of glycoside hydrolases.

    PubMed

    Naumoff, D G

    2011-06-01

    This review deals with structural and functional features of glycoside hydrolases, a widespread group of enzymes present in almost all living organisms. Their catalytic domains are grouped into 120 amino acid sequence-based families in the international classification of the carbohydrate-active enzymes (CAZy database). At a higher hierarchical level some of these families are combined in 14 clans. Enzymes of the same clan have common evolutionary origin of their genes and share the most important functional characteristics such as composition of the active center, anomeric configuration of cleaved glycosidic bonds, and molecular mechanism of the catalyzed reaction (either inverting, or retaining). There are now extensive data in the literature concerning the relationship between glycoside hydrolase families belonging to different clans and/or included in none of them, as well as information on phylogenetic protein relationship within particular families. Summarizing these data allows us to propose a multilevel hierarchical classification of glycoside hydrolases and their homologs. It is shown that almost the whole variety of the enzyme catalytic domains can be brought into six main folds, large groups of proteins having the same three-dimensional structure and the supposed common evolutionary origin. PMID:21639842

  14. The Supervised Hierarchical Dirichlet Process.

    PubMed

    Dai, Andrew M; Storkey, Amos J

    2015-02-01

    We propose the supervised hierarchical Dirichlet process (sHDP), a nonparametric generative model for the joint distribution of a group of observations and a response variable directly associated with that whole group. We compare the sHDP with another leading method for regression on grouped data, the supervised latent Dirichlet allocation (sLDA) model. We evaluate our method on two real-world classification problems and two real-world regression problems. Bayesian nonparametric regression models based on the Dirichlet process, such as the Dirichlet process-generalised linear models (DP-GLM) have previously been explored; these models allow flexibility in modelling nonlinear relationships. However, until now, hierarchical Dirichlet process (HDP) mixtures have not seen significant use in supervised problems with grouped data since a straightforward application of the HDP on the grouped data results in learnt clusters that are not predictive of the responses. The sHDP solves this problem by allowing for clusters to be learnt jointly from the group structure and from the label assigned to each group. PMID:26353239

  15. Source Authentication for Code Dissemination Supporting Dynamic Packet Size in Wireless Sensor Networks †

    PubMed Central

    Kim, Daehee; Kim, Dongwan; An, Sunshin

    2016-01-01

    Code dissemination in wireless sensor networks (WSNs) is a procedure for distributing a new code image over the air in order to update programs. Due to the fact that WSNs are mostly deployed in unattended and hostile environments, secure code dissemination ensuring authenticity and integrity is essential. Recent works on dynamic packet size control in WSNs allow enhancing the energy efficiency of code dissemination by dynamically changing the packet size on the basis of link quality. However, the authentication tokens attached by the base station become useless in the next hop where the packet size can vary according to the link quality of the next hop. In this paper, we propose three source authentication schemes for code dissemination supporting dynamic packet size. Compared to traditional source authentication schemes such as μTESLA and digital signatures, our schemes provide secure source authentication under the environment, where the packet size changes in each hop, with smaller energy consumption. PMID:27409616

  16. Source Authentication for Code Dissemination Supporting Dynamic Packet Size in Wireless Sensor Networks.

    PubMed

    Kim, Daehee; Kim, Dongwan; An, Sunshin

    2016-01-01

    Code dissemination in wireless sensor networks (WSNs) is a procedure for distributing a new code image over the air in order to update programs. Due to the fact that WSNs are mostly deployed in unattended and hostile environments, secure code dissemination ensuring authenticity and integrity is essential. Recent works on dynamic packet size control in WSNs allow enhancing the energy efficiency of code dissemination by dynamically changing the packet size on the basis of link quality. However, the authentication tokens attached by the base station become useless in the next hop where the packet size can vary according to the link quality of the next hop. In this paper, we propose three source authentication schemes for code dissemination supporting dynamic packet size. Compared to traditional source authentication schemes such as μTESLA and digital signatures, our schemes provide secure source authentication under the environment, where the packet size changes in each hop, with smaller energy consumption. PMID:27409616

  17. 3.0 Tesla vs 1.5 Tesla breast magnetic resonance imaging in newly diagnosed breast cancer patients

    PubMed Central

    Butler, Reni S; Chen, Christine; Vashi, Reena; Hooley, Regina J; Philpotts, Liane E

    2013-01-01

    AIM: To compare 3.0 Tesla (T) vs 1.5T magnetic resonance (MR) imaging systems in newly diagnosed breast cancer patients. METHODS: Upon Institutional Review Board approval, a Health Insurance Portability and Accountability Act-compliant retrospective review of 147 consecutive 3.0T MR examinations and 98 consecutive 1.5T MR examinations in patients with newly diagnosed breast cancer between 7/2009 and 5/2010 was performed. Eleven patients who underwent neoadjuvant chemotherapy in the 3.0T group were excluded. Mammographically occult suspicious lesions (BIRADS Code 4 and 5) additional to the index cancer in the ipsilateral and contralateral breast were identified. Lesion characteristics and pathologic diagnoses were recorded, and results achieved with both systems compared. Statistical significance was analyzed using Fisher’s exact test. RESULTS: In the 3.0T group, 206 suspicious lesions were identified in 55% (75/136) of patients and 96% (198/206) of these lesions were biopsied. In the 1.5T group, 98 suspicious lesions were identified in 53% (52/98) of patients and 90% (88/98) of these lesions were biopsied. Biopsy results yielded additional malignancies in 24% of patients in the 3.0T group vs 14% of patients in the 1.5T group (33/136 vs 14/98, P = 0.07). Average size and histology of the additional cancers was comparable. Of patients who had a suspicious MR imaging study, additional cancers were found in 44% of patients in the 3.0T group vs 27% in the 1.5T group (33/75 vs 14/52, P = 0.06), yielding a higher positive predictive value (PPV) for biopsies performed with the 3.0T system. CONCLUSION: 3.0T MR imaging detected more additional malignancies in patients with newly diagnosed breast cancer and yielded a higher PPV for biopsies performed with the 3.0T system. PMID:24003354

  18. The Case for a Hierarchical Cosmology

    ERIC Educational Resources Information Center

    Vaucouleurs, G. de

    1970-01-01

    The development of modern theoretical cosmology is presented and some questionable assumptions of orthodox cosmology are pointed out. Suggests that recent observations indicate that hierarchical clustering is a basic factor in cosmology. The implications of hierarchical models of the universe are considered. Bibliography. (LC)

  19. Discursive Hierarchical Patterning in Economics Cases

    ERIC Educational Resources Information Center

    Lung, Jane

    2011-01-01

    This paper attempts to apply Lung's (2008) model of the discursive hierarchical patterning of cases to a closer and more specific study of Economics cases and proposes a model of the distinct discursive hierarchical patterning of the same. It examines a corpus of 150 Economics cases with a view to uncovering the patterns of discourse construction.…

  20. Hierarchical Latent Trait Approach in Test Analysis.

    ERIC Educational Resources Information Center

    Dimitrov, Dimiter M.

    An approach is described that reveals the hierarchical test structure (HTS) based on the cognitive demands of the test items, and conducts a linear trait modeling by using the HST elements as item difficulty components. This approach, referred to as the Hierarchical Latent Trait Approach (HLTA), employs an algorithm that allows all test items to…

  1. Hierarchical Classes Modeling of Rating Data

    ERIC Educational Resources Information Center

    Van Mechelen, Iven; Lombardi, Luigi; Ceulemans, Eva

    2007-01-01

    Hierarchical classes (HICLAS) models constitute a distinct family of structural models for N-way N-mode data. All members of the family include N simultaneous and linked classifications of the elements of the N modes implied by the data; those classifications are organized in terms of hierarchical, if-then-type relations. Moreover, the models are…

  2. Genetic Network Inference Using Hierarchical Structure.

    PubMed

    Kimura, Shuhei; Tokuhisa, Masato; Okada-Hatakeyama, Mariko

    2016-01-01

    Many methods for inferring genetic networks have been proposed, but the regulations they infer often include false-positives. Several researchers have attempted to reduce these erroneous regulations by proposing the use of a priori knowledge about the properties of genetic networks such as their sparseness, scale-free structure, and so on. This study focuses on another piece of a priori knowledge, namely, that biochemical networks exhibit hierarchical structures. Based on this idea, we propose an inference approach that uses the hierarchical structure in a target genetic network. To obtain a reasonable hierarchical structure, the first step of the proposed approach is to infer multiple genetic networks from the observed gene expression data. We take this step using an existing method that combines a genetic network inference method with a bootstrap method. The next step is to extract a hierarchical structure from the inferred networks that is consistent with most of the networks. Third, we use the hierarchical structure obtained to assign confidence values to all candidate regulations. Numerical experiments are also performed to demonstrate the effectiveness of using the hierarchical structure in the genetic network inference. The improvement accomplished by the use of the hierarchical structure is small. However, the hierarchical structure could be used to improve the performances of many existing inference methods. PMID:26941653

  3. A Survey on Clustering Routing Protocols in Wireless Sensor Networks

    PubMed Central

    Liu, Xuxun

    2012-01-01

    The past few years have witnessed increased interest in the potential use of wireless sensor networks (WSNs) in a wide range of applications and it has become a hot research area. Based on network structure, routing protocols in WSNs can be divided into two categories: flat routing and hierarchical or clustering routing. Owing to a variety of advantages, clustering is becoming an active branch of routing technology in WSNs. In this paper, we present a comprehensive and fine grained survey on clustering routing protocols proposed in the literature for WSNs. We outline the advantages and objectives of clustering for WSNs, and develop a novel taxonomy of WSN clustering routing methods based on complete and detailed clustering attributes. In particular, we systematically analyze a few prominent WSN clustering routing protocols and compare these different approaches according to our taxonomy and several significant metrics. Finally, we summarize and conclude the paper with some future directions. PMID:23112649

  4. Communications device identification methods, communications methods, wireless communications readers, wireless communications systems, and articles of manufacture

    DOEpatents

    Steele, Kerry D [Kennewick, WA; Anderson, Gordon A [Benton City, WA; Gilbert, Ronald W [Morgan Hill, CA

    2011-02-01

    Communications device identification methods, communications methods, wireless communications readers, wireless communications systems, and articles of manufacture are described. In one aspect, a communications device identification method includes providing identification information regarding a group of wireless identification devices within a wireless communications range of a reader, using the provided identification information, selecting one of a plurality of different search procedures for identifying unidentified ones of the wireless identification devices within the wireless communications range, and identifying at least some of the unidentified ones of the wireless identification devices using the selected one of the search procedures.

  5. Hierarchically nanostructured materials for sustainable environmental applications

    PubMed Central

    Ren, Zheng; Guo, Yanbing; Liu, Cai-Hong; Gao, Pu-Xian

    2013-01-01

    This review presents a comprehensive overview of the hierarchical nanostructured materials with either geometry or composition complexity in environmental applications. The hierarchical nanostructures offer advantages of high surface area, synergistic interactions, and multiple functionalities toward water remediation, biosensing, environmental gas sensing and monitoring as well as catalytic gas treatment. Recent advances in synthetic strategies for various hierarchical morphologies such as hollow spheres and urchin-shaped architectures have been reviewed. In addition to the chemical synthesis, the physical mechanisms associated with the materials design and device fabrication have been discussed for each specific application. The development and application of hierarchical complex perovskite oxide nanostructures have also been introduced in photocatalytic water remediation, gas sensing, and catalytic converter. Hierarchical nanostructures will open up many possibilities for materials design and device fabrication in environmental chemistry and technology. PMID:24790946

  6. Processing of hierarchical syntactic structure in music

    PubMed Central

    Koelsch, Stefan; Rohrmeier, Martin; Torrecuso, Renzo; Jentschke, Sebastian

    2013-01-01

    Hierarchical structure with nested nonlocal dependencies is a key feature of human language and can be identified theoretically in most pieces of tonal music. However, previous studies have argued against the perception of such structures in music. Here, we show processing of nonlocal dependencies in music. We presented chorales by J. S. Bach and modified versions in which the hierarchical structure was rendered irregular whereas the local structure was kept intact. Brain electric responses differed between regular and irregular hierarchical structures, in both musicians and nonmusicians. This finding indicates that, when listening to music, humans apply cognitive processes that are capable of dealing with long-distance dependencies resulting from hierarchically organized syntactic structures. Our results reveal that a brain mechanism fundamental for syntactic processing is engaged during the perception of music, indicating that processing of hierarchical structure with nested nonlocal dependencies is not just a key component of human language, but a multidomain capacity of human cognition. PMID:24003165

  7. Hierarchically Nanostructured Materials for Sustainable Environmental Applications

    NASA Astrophysics Data System (ADS)

    Ren, Zheng; Guo, Yanbing; Liu, Cai-Hong; Gao, Pu-Xian

    2013-11-01

    This article presents a comprehensive overview of the hierarchical nanostructured materials with either geometry or composition complexity in environmental applications. The hierarchical nanostructures offer advantages of high surface area, synergistic interactions and multiple functionalities towards water remediation, environmental gas sensing and monitoring as well as catalytic gas treatment. Recent advances in synthetic strategies for various hierarchical morphologies such as hollow spheres and urchin-shaped architectures have been reviewed. In addition to the chemical synthesis, the physical mechanisms associated with the materials design and device fabrication have been discussed for each specific application. The development and application of hierarchical complex perovskite oxide nanostructures have also been introduced in photocatalytic water remediation, gas sensing and catalytic converter. Hierarchical nanostructures will open up many possibilities for materials design and device fabrication in environmental chemistry and technology.

  8. Hierarchically nanostructured materials for sustainable environmental applications.

    PubMed

    Ren, Zheng; Guo, Yanbing; Liu, Cai-Hong; Gao, Pu-Xian

    2013-01-01

    This review presents a comprehensive overview of the hierarchical nanostructured materials with either geometry or composition complexity in environmental applications. The hierarchical nanostructures offer advantages of high surface area, synergistic interactions, and multiple functionalities toward water remediation, biosensing, environmental gas sensing and monitoring as well as catalytic gas treatment. Recent advances in synthetic strategies for various hierarchical morphologies such as hollow spheres and urchin-shaped architectures have been reviewed. In addition to the chemical synthesis, the physical mechanisms associated with the materials design and device fabrication have been discussed for each specific application. The development and application of hierarchical complex perovskite oxide nanostructures have also been introduced in photocatalytic water remediation, gas sensing, and catalytic converter. Hierarchical nanostructures will open up many possibilities for materials design and device fabrication in environmental chemistry and technology. PMID:24790946

  9. Adaptive Sampling in Hierarchical Simulation

    SciTech Connect

    Knap, J; Barton, N R; Hornung, R D; Arsenlis, A; Becker, R; Jefferson, D R

    2007-07-09

    We propose an adaptive sampling methodology for hierarchical multi-scale simulation. The method utilizes a moving kriging interpolation to significantly reduce the number of evaluations of finer-scale response functions to provide essential constitutive information to a coarser-scale simulation model. The underlying interpolation scheme is unstructured and adaptive to handle the transient nature of a simulation. To handle the dynamic construction and searching of a potentially large set of finer-scale response data, we employ a dynamic metric tree database. We study the performance of our adaptive sampling methodology for a two-level multi-scale model involving a coarse-scale finite element simulation and a finer-scale crystal plasticity based constitutive law.

  10. Hierarchical condensation near phase equilibrium

    NASA Astrophysics Data System (ADS)

    Olemskoi, A. I.; Yushchenko, O. V.; Borisyuk, V. N.; Zhilenko, T. I.; Kosminska, Yu. O.; Perekrestov, V. I.

    2012-06-01

    A novel mechanism of new phase formation is studied both experimentally and theoretically in the example of quasi-equilibrium stationary condensation in an ion-plasma sputterer. Copper condensates are obtained to demonstrate that a specific network structure is formed as a result of self-assembly in the course of deposition. The fractal pattern related is inherent in the phenomena of diffusion limited aggregation. Condensate nuclei are shown to form statistical ensemble of hierarchically subordinated objects distributed in ultrametric space. The Langevin equation and the Fokker-Planck equation related are found to describe stationary distribution of thermodynamic potential variations at condensation. Time dependence of the formation probability of branching structures is found to clarify the experimental situation.

  11. Core Recursive Hierarchical Image Segmentation

    NASA Technical Reports Server (NTRS)

    Tilton, James

    2011-01-01

    The Recursive Hierarchical Image Segmentation (RHSEG) software has been repackaged to provide a version of the RHSEG software that is not subject to patent restrictions and that can be released to the general public through NASA GSFC's Open Source release process. Like the Core HSEG Software Package, this Core RHSEG Software Package also includes a visualization program called HSEGViewer along with a utility program HSEGReader. It also includes an additional utility program called HSEGExtract. The unique feature of the Core RHSEG package is that it is a repackaging of the RHSEG technology designed to specifically avoid the inclusion of the certain software technology. Unlike the Core HSEG package, it includes the recursive portions of the technology, but does not include processing window artifact elimination technology.

  12. Cluster assembly of hierarchical nanostructures

    SciTech Connect

    Siegel, R.W.

    1992-02-01

    In the past few years, atom clusters with diameters in the range of 2--20 nm of a variety of materials, including both metals and ceramics, have been synthesized by evaporation and condensation in high-purity gases and subsequently consolidated in situ under ultrahigh vacuum conditions to create nanophase materials. These new utlrafine-grained materials have properties that are often significantly different and considerably improved relative to those of their coarser-grained counterparts owing to both their small grain-size scale and the large percentage of their atoms in grain boundary environments. Since their properties can be engineered during the synthesis and processing steps, cluster-assembled materials appear to have significant potential for the introduction of a hierarchy of both structure and properties. Some of the recent research on nanophase materials related to properties and scale are reviewed and some of the possibilities for synthesizing hierarchical nanostructures via cluster assembly are considered.

  13. Hierarchical analysis of molecular spectra

    SciTech Connect

    Davis, M.J.

    1996-03-01

    A novel representation of molecular spectra in terms of hierarchical trees has proven to be an important aid for the study of many significant problems in gas-phase chemical dynamics. Trees are generated from molecular spectra by monitoring the changes that occur in a spectrum as resolution is changed in a continuous manner. A tree defines a genealogy among all lines of a spectrum. This allows for a detailed understanding of the assignment of features of a spectrum that may be difficult to obtain any other way as well as an understanding of intramolecular energy transfer time scales, mechanisms, and pathways. The methodology has been applied to several problems: transition state spectroscopy, intramolecular energy transfer in highly excited molecules, high-resolution overtone spectroscopy, and the nature of the classical-quantum correspondence when there is classical chaos (``quantum chaos``).

  14. Prospects for 6 to 10 tesla magnets for a TEVATRON upgrade

    SciTech Connect

    Mantsch, Paul M.

    1988-07-08

    The first SSC physics is at least 10 years away. An upgrade of the Fermilab Tevatron will ensure the continuity of a vigorous high-energy physics program until the SSC turns on. Three basic proposals are under consideration: /bar p/p at 3 /times/ 10/sup 31/ --Increase luminosity by improvements to the p source. pp at 1 TeV and 2 /times/ 10/sup 32/--Move the main ring to a new tunnel, build a second Tevatron ring, and /bar p/p > 1.5 TeV and 7 /times/ 10/sup 30/--Replace the tevatron with a higher energy ring. The last two options requires about a hundred 6.6-tesla dipoles in addition to a ring of Tevatron strength (4.4 T) magnets. These higher-field magnets are necessary in both rings to lengthen the straight sections in order to realize the collision optics. The third option requires a ring of magnets of 6.6 T or slightly higher to replace the present Tevatron plus a number of special 8--9 tesla magnets. The viability of the high-energy option then depends on the practicality of sizable numbers of reliable 8--9 tesla dipoles as well as 800 6.6-tesla dipoles. The following develops a specification for an 8.8 T dipole, examines the design considerations and reviews the current state of high-field magnet development. 22 figs., 3 tabs.

  15. Shot noise startup of the 6 nm SASE FEL at the TESLA test facility

    NASA Astrophysics Data System (ADS)

    Pierini, P.; Fawley, W. M.

    1996-02-01

    We present here the results of an extensive simulation activity for the TESLA SASE FEL. We have used the program GINGER to determine the FEL saturation length and the power fluctuations from shot to shot. The spectral properties of the output power and the correlation functions are investigated and compared with available theoretical models.

  16. The development of a TESLA recirculator with superconducting accelerating structures in Ukraine

    NASA Astrophysics Data System (ADS)

    Guk, I. S.; Dovbnya, A. N.

    2008-12-01

    The recirculator project, which is to be built at the National Science Center, Kharkov Institute of Physics and Technology (NSC KIPT), is presented. The basic solutions incorporated in the design are given. The TESLA superconducting section is chosen as the accelerating structure of an accelerating complex.

  17. 77 FR 60672 - Grant of Authority for Subzone Status; Tesla Motors, Inc., (Electric Passenger Vehicles), Palo...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-04

    ..., notice inviting public comment has been given in the Federal Register (77 FR 2269, 1-17-2012) and the... Foreign-Trade Zones Board Grant of Authority for Subzone Status; Tesla Motors, Inc., (Electric Passenger... establish a special-purpose subzone at the electric passenger vehicle manufacturing facilities of...

  18. Design study of 15-Tesla RHQT Nb3Al block type dipole magnet

    SciTech Connect

    Yamada, R.; Ambrosio, G.; Barzi, E.; Kashikin, V.; Kikuchi, A.; Novitski, I.; Takeuchi, T.; Wake, M.; Zlobin, A.; /Fermilab /NIMC, Tsukuba /KEK, Tsukuba

    2005-09-01

    The design study of the block type 15-Tesla RHQT Nb{sub 3}Al dipole magnet, and its merits over Nb{sub 3}Sn magnets are presented. The copper stabilized RHQT Nb{sub 3}Al strand is now becoming commercially available for the application to the accelerator magnets. A 1 mm diameter RHQT Nb{sub 3}Al strand with filament size about 50 {mu}, non-copper Jc about 1000 A/mm{sup 2} at 15 Tesla at 4.2K, copper ratio of 50%, can now be produced over several hundred meters. The stress and strain characteristics of the Nb{sub 3}Al strand are superior to the Nb{sub 3}Sn strand. Another advantage is that it can tolerate a longitudinal strain up to 0.55%. The RHQT Nb{sub 3}Al Rutherford cable will have less chance of contamination of the stabilizer, compared to Nb{sub 3}Sn cable. These characteristics of the RHQT Nb{sub 3}Al will be beneficial for designing and producing 15-Tesla dipole magnets. An example 15-Tesla magnet cross section, utilizing the RHQT Nb{sub 3}Sn strand is presented. A systematic investigation on RHQT Nb{sub 3}Al strands, its Rutherford cables, and building a small racetrack magnet for cable testing are proposed.

  19. Encouraging a "Romantic Understanding" of Science: The Effect of the Nikola Tesla Story

    ERIC Educational Resources Information Center

    Hadzigeorgiou, Yannis; Klassen, Stephen; Klassen, Cathrine Froese

    2012-01-01

    The purpose of this paper is to discuss and apply the notion of romantic understanding by outlining its features and its potential role in science education, to identify its features in the story of Nikola Tesla, and to describe an empirical study conducted to determine the effect of telling such a story to Grade 9 students. Elaborated features of…

  20. VCSEL arrays for optical wireless systems

    NASA Astrophysics Data System (ADS)

    Tada, Katsuhisa; Nitatori, Koichi; Iwamoto, Takashi; Miura, Takamitsu; Sakai, Masahisa

    2001-05-01

    Now we have studied the development of the optical devices used in optical wireless communication systems. For optical wireless systems, the emitted light should have an intensity distribution in the shape of a pill-box. Use of VCSEL array was believed to allow the emitted light to have pill-box distribution and we performed the study concerning the optimum VCSEL array for optical wireless systems. This article describes the development of the VCSEL array for optical wireless systems.

  1. Proposal of Wireless Traffic Control Schemes for Wireless LANs

    NASA Astrophysics Data System (ADS)

    Hiraguri, Takefumi; Ichikawa, Takeo; Iizuka, Masataka; Kubota, Shuji

    This paper proposes two traffic control schemes to support the communication quality of multimedia streaming services such as VoIP and audio/video over IEEE 802.11 wireless LAN systems. The main features of the proposed scheme are bandwidth control for each flow of the multimedia streaming service and load balancing between access points (APs) of the wireless LAN by using information of data link, network and transport layers. The proposed schemes are implemented on a Linux machine which is called the wireless traffic controller (WTC). The WTC connects a high capacity backbone network and an access network to which the APs are attached. We evaluated the performance of the proposed WTC and confirmed that the communication quality of the multimedia streaming would be greatly improved by using this technique.

  2. Wireless Andrew: Everywhere You Want To Be.

    ERIC Educational Resources Information Center

    Futhey, Tracy

    2000-01-01

    Describes the wireless local area network at Carnegie Mellon University. Highlights include classroom applications, particularly in the Business School; the use of laptop computers configured with wireless technology; handheld computers, including use for testing; and assuring appropriate uses of wireless technology. (LRW)

  3. 77 FR 64446 - Wireless Microphones Proceeding

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-22

    ... Docket No. 02-380, Second Memorandum Opinion and Order, 75 FR 75814, 25 FCC Rcd 18661 (2010) (TV White... Rulemaking, 75 FR 3622, 75 FR 3682, 25 FCC Rcd 643 (2010) (Wireless Microphones Order and Wireless... Memorandum Opinion and Order, 77 FR 29236, 27 FCC Rcd 3692 (2012). Background In the Wireless...

  4. A Wireless Communications Systems Laboratory Course

    ERIC Educational Resources Information Center

    Guzelgoz, Sabih; Arslan, Huseyin

    2010-01-01

    A novel wireless communications systems laboratory course is introduced. The course teaches students how to design, test, and simulate wireless systems using modern instrumentation and computer-aided design (CAD) software. One of the objectives of the course is to help students understand the theoretical concepts behind wireless communication…

  5. Exploring the hierarchical structure in road network

    NASA Astrophysics Data System (ADS)

    He, Jing; Zhang, Hong; Lan, Tian; Cao, Weiwei; Wu, Xun

    2015-12-01

    Hierarchical structure of road network has received intensive attention either in urban planning or multi-scale representation. On the one hand, high-efficiency traffic flow counts on a reasonable hierarchical structure. On the other hand, it is a guide-line for cartographic generalization of road network. The paper attempts to investigate the hierarchical structure of a road network from two perspectives, a) the ht-index in terms of the degree connectivity, which was proposed to quantify the scaling and hierarchical structure of the network, b) the renormalization process, originated from complex network analysis, which is able to uncover the self-similarity of a network and reveal its hierarchical structure. We argue that the first point exhibits a big picture of the whole network, revealing the depth of the hierarchy, while the second point further illustrates how the nodes are organized to form a hierarchical structure at different scales. The hierarchical structures of 6 road networks in reality are examined accordingly. Results show that both indices are able to reveal the complexity of the hierarchy of a network. These conclusions can be beneficial to the road network generalization.

  6. Wireless device monitoring systems and monitoring devices, and associated methods

    DOEpatents

    McCown, Steven H; Derr, Kurt W; Rohde, Kenneth W

    2014-05-27

    Wireless device monitoring systems and monitoring devices include a communications module for receiving wireless communications of a wireless device. Processing circuitry is coupled with the communications module and configured to process the wireless communications to determine whether the wireless device is authorized or unauthorized to be present at the monitored area based on identification information of the wireless device. Methods of monitoring for the presence and identity of wireless devices are also provided.

  7. Evolutionary games in wireless networks.

    PubMed

    Tembine, Hamidou; Altman, Eitan; El-Azouzi, Rachid; Hayel, Yezekael

    2010-06-01

    We consider a noncooperative interaction among a large population of mobiles that interfere with each other through many local interactions. The first objective of this paper is to extend the evolutionary game framework to allow an arbitrary number of mobiles that are involved in a local interaction. We allow for interactions between mobiles that are not necessarily reciprocal. We study 1) multiple-access control in a slotted Aloha-based wireless network and 2) power control in wideband code-division multiple-access wireless networks. We define and characterize the equilibrium (called evolutionarily stable strategy) for these games and study the influence of wireless channels and pricing on the evolution of dynamics and the equilibrium. PMID:19963703

  8. Wireless Communications in Reverberant Environments

    NASA Astrophysics Data System (ADS)

    Measel, Ryan Thomas

    Implementation of WLANs in reverberant environments, such as industrial facilities, naval vessels, aircraft, and spacecraft, has proven challenging, because rich electromagnetic scattering can degrade link quality through multipath interference. As a result, the adoption of Wireless LANs in these environments has been slow. Previous studies concerning reverberant environments have focused on characterizing electromagnetic properties for the purpose of electromagnetic compatibility testing. Little attention has been given to the performance of wireless communications. In this effort, the effect of electromagnetic reverberance on wireless communications is investigated in order to assess the feasibility of WLAN deployment. Work centered around two experimental measurement campaigns. The first campaign was performed in coupled reverberation chambers. The reverberation chambers provided a controllable environment which was configured to emulate the reverberance of below-deck spaces on a naval vessel. The process for quantifying and configuring the electromagnetic properties of a reverberation chamber is presented. The second campaign was performed on a naval vessel. Experimentation was conducted in a variety of locations on the ship. Locations were selected to represent a wide range of practical environments. Across both campaigns, several environment and node parameters were evaluated: level of reverberance, cavity coupling (effective aperture size), and LOS versus NLOS links. Additionally, advanced physical layer schemes and reconfigurable antennas are presented as methods to improve performance and mitigate multipath interference. To perform this work, a measurement platform and testing protocol were developed for systematic characterization of wireless communications in reverberant environments. The primary contributions of this work are empirical characterization of wireless communications in reverberant environments, approaches to improving the performance of

  9. Secure Adaptive Topology Control for Wireless Ad-Hoc Sensor Networks

    PubMed Central

    Hsueh, Ching-Tsung; Li, Yu-Wei; Wen, Chih-Yu; Ouyang, Yen-Chieh

    2010-01-01

    This paper presents a secure decentralized clustering algorithm for wireless ad-hoc sensor networks. The algorithm operates without a centralized controller, operates asynchronously, and does not require that the location of the sensors be known a priori. Based on the cluster-based topology, secure hierarchical communication protocols and dynamic quarantine strategies are introduced to defend against spam attacks, since this type of attacks can exhaust the energy of sensor nodes and will shorten the lifetime of a sensor network drastically. By adjusting the threshold of infected percentage of the cluster coverage, our scheme can dynamically coordinate the proportion of the quarantine region and adaptively achieve the cluster control and the neighborhood control of attacks. Simulation results show that the proposed approach is feasible and cost effective for wireless sensor networks. PMID:22205866

  10. NASA thesaurus. Volume 1: Hierarchical Listing

    NASA Technical Reports Server (NTRS)

    1988-01-01

    There are over 17,000 postable terms and nearly 4,000 nonpostable terms approved for use in the NASA scientific and technical information system in the Hierarchical Listing of the NASA Thesaurus. The generic structure is presented for many terms. The broader term and narrower term relationships are shown in an indented fashion that illustrates the generic structure better than the more widely used BT and NT listings. Related terms are generously applied, thus enhancing the usefulness of the Hierarchical Listing. Greater access to the Hierarchical Listing may be achieved with the collateral use of Volume 2 - Access Vocabulary and Volume 3 - Definitions.

  11. NASA Thesaurus. Volume 1: Hierarchical listing

    NASA Technical Reports Server (NTRS)

    1982-01-01

    There are 16,713 postable terms and 3,716 nonpostable terms approved for use in the NASA scientific and technical information system in the Hierarchical Listing of the NASA Thesaurus. The generic structure is presented for many terms. The broader term and narrower term relationships are shown in an indented fashion that illustrates the generic structure better than the more widely used BT and NT listings. Related terms are generously applied, thus enhancing the usefulness of the Hierarchical Listing. Greater access to the Hierarchical Listing may be achieved with the collateral use of Volume 2 - Access Vocabulary.

  12. NASA thesaurus. Volume 1: Hierarchical listing

    NASA Technical Reports Server (NTRS)

    1985-01-01

    There are 16,835 postable terms and 3,765 nonpostable terms approved for use in the NASA scientific and technical information system in the Hierarchical Listing of the NASA Thesaurus. The generic structure is presented for many terms. The broader term and narrower term relationships are shown in an indented fashion that illustrates the generic structure better than the more widely used BT and NT listings. Related terms are generously applied, thus enhancing the usefulness of the Hierarchical Listing. Greater access to the Hierarchical Listing may be achieved with the collateral use of Volume 2 - Access Vocabulary.

  13. Wireless Technologies Implications for Power Systems

    SciTech Connect

    Fuhr, Peter L; Manges, Wayne W; Schweitzer, Patrick; Kagan, Hesh

    2010-01-01

    Wireless technologies have advanced well beyond simple SCADA radio systems and point-to-point links. The current applications supported by industrial-grade wireless sensors and systems range from field measurements (classic I/O) to voice, video, asset tracking, mobile operators, etc. Which such a wide array of supported applications, the belief that wireless technology will only impact power systems in terms of wireless sensors is shortsighted. This paper, coauthored by a group of individuals intimately involved in the general realm of industrial wireless , presents a simple snapshot of current radio technologies that are used (or seriously contemplated for use) in power systems.

  14. Wireless Augmented Reality Communication System

    NASA Technical Reports Server (NTRS)

    Devereaux, Ann (Inventor); Jedrey, Thomas (Inventor); Agan, Martin (Inventor)

    2015-01-01

    A portable unit is for video communication to select a user name in a user name network. A transceiver wirelessly accesses a communication network through a wireless connection to a general purpose node coupled to the communication network. A user interface can receive user input to log on to a user name network through the communication network. The user name network has a plurality of user names, at least one of the plurality of user names is associated with a remote portable unit, logged on to the user name network and available for video communication.

  15. WIRELESS FOR A NUCLEAR FACILITY

    SciTech Connect

    Shull, D; Joe Cordaro, J

    2007-03-28

    The introduction of wireless technology into a government site where nuclear material is processed and stored brings new meaning to the term ''harsh environment''. At SRNL, we are attempting to address not only the harsh RF and harsh physical environment common to industrial facilities, but also the ''harsh'' regulatory environment necessitated by the nature of the business at our site. We will discuss our concepts, processes, and expected outcomes in our attempts to surmount the roadblocks and reap the benefits of wireless in our ''factory''.

  16. Wireless technology for integrated manufacturing

    SciTech Connect

    Manges, W.W.; Allgood, G.O.; Shourbaji, A.A.

    1996-08-01

    This paper describes the ground breaking work in Oak Ridge facilities that now leads us to the brink of the wireless revolution in manufacturing. The focus is on solving tough technological problems necessary for success and addressing the critical issues of throughput, security, reliability, and robustness in applying wireless technology to manufacturing processes. Innovative solutions to these problems are highlighted through detailed designs and testbed implementations that demonstrate key concepts. The DOE-Oak Ridge complex represented by the Oak Ridge Centers for Manufacturing Technologies (ORCMT) continues to develop these technologies and will continue to focus on solving tough manufacturing problems.

  17. Wireless Ways: Business and Personal Applications of Wireless Technology.

    ERIC Educational Resources Information Center

    Chung, Joe

    2001-01-01

    Describes the Art Technology Group (ATG), an electronic business and customer management company, and the work they have done with wireless technology. Highlights include designing virtual offices and supporting the resulting virtual community; the mobility it allows; problems with bandwidth; and display issues. (LRW)

  18. Cross-Layer Protocol Combining Tree Routing and TDMA Slotting in Wireless Sensor Networks

    NASA Astrophysics Data System (ADS)

    Bai, Ronggang; Ji, Yusheng; Lin, Zhiting; Wang, Qinghua; Zhou, Xiaofang; Qu, Yugui; Zhao, Baohua

    Being different from other networks, the load and direction of data traffic for wireless sensor networks are rather predictable. The relationships between nodes are cooperative rather than competitive. These features allow the design approach of a protocol stack to be able to use the cross-layer interactive way instead of a hierarchical structure. The proposed cross-layer protocol CLWSN optimizes the channel allocation in the MAC layer using the information from the routing tables, reduces the conflicting set, and improves the throughput. Simulations revealed that it outperforms SMAC and MINA in terms of delay and energy consumption.

  19. A comparative study of routing protocols of heterogeneous wireless sensor networks.

    PubMed

    Han, Guangjie; Jiang, Xu; Qian, Aihua; Rodrigues, Joel J P C; Cheng, Long

    2014-01-01

    Recently, heterogeneous wireless sensor network (HWSN) routing protocols have drawn more and more attention. Various HWSN routing protocols have been proposed to improve the performance of HWSNs. Among these protocols, hierarchical HWSN routing protocols can improve the performance of the network significantly. In this paper, we will evaluate three hierarchical HWSN protocols proposed recently--EDFCM, MCR, and EEPCA--together with two previous classical routing protocols--LEACH and SEP. We mainly focus on the round of the first node dies (also called the stable period) and the number of packets sent to sink, which is an important aspect to evaluate the monitoring ability of a protocol. We conduct a lot of experiments and simulations on Matlab to analyze the performance of the five routing protocols. PMID:25050393

  20. Hierarchical model for distributed seismicity

    SciTech Connect

    Tejedor, Alejandro; Gomez, Javier B.; Pacheco, Amalio F.

    2010-07-15

    A cellular automata model for the interaction between seismic faults in an extended region is presented. Faults are represented by boxes formed by a different number of sites and located in the nodes of a fractal tree. Both the distribution of box sizes and the interaction between them is assumed to be hierarchical. Load particles are randomly added to the system, simulating the action of external tectonic forces. These particles fill the sites of the boxes progressively. When a box is full it topples, some of the particles are redistributed to other boxes and some of them are lost. A box relaxation simulates the occurrence of an earthquake in the region. The particle redistributions mostly occur upwards (to larger faults) and downwards (to smaller faults) in the hierarchy producing new relaxations. A simple and efficient bookkeeping of the information allows the running of systems with more than fifty million faults. This model is consistent with the definition of magnitude, i.e., earthquakes of magnitude m take place in boxes with a number of sites ten times bigger than those boxes responsible for earthquakes with a magnitude m-1 which are placed in the immediate lower level of the hierarchy. The three parameters of the model have a geometrical nature: the height or number of levels of the fractal tree, the coordination of the tree and the ratio of areas between boxes in two consecutive levels. Besides reproducing several seismicity properties and regularities, this model is used to test the performance of some precursory patterns.

  1. Dynamic visualization of hierarchical data

    NASA Astrophysics Data System (ADS)

    Senay, Hikmet; Saltz, Jeffrey S.

    1997-06-01

    Many business data applications involve several hierarchies reflecting inherent structure of the underlying domains. Often, these hierarchies are presented in a spreadsheet like format, showing a single hierarchy in a tabular form with drill down and roll up capabilities. Although this approach works for simple hierarchies and small data sets, they tend to break as the hierarchies become more complex or the size of data set increases. An alternative approach, which has the potential to work equally well with complex hierarchies and large data sets, is to devise a visualization front-end for dynamically altering and displaying views of data under user control. Toward this end, we have developed a prototype of a visualization tool to view large financial data sets which typically involve multiple hierarchies. The tool not only acts as a data presentation medium, but also serves as a graphical means to form complex queries and interact with data. Its presentation structure uses hierarchical labels, which may be drilled down or rolled up, and displayable cell objects, which may have arbitrary complexity. Its data interface allows users to select data of interest, map data parameters to visual attributes, set threshold values to focus on interesting data, and read data values associated with cell objects.

  2. Geophysical Inversion Through Hierarchical Scheme

    NASA Astrophysics Data System (ADS)

    Furman, A.; Huisman, J. A.

    2010-12-01

    Geophysical investigation is a powerful tool that allows non-invasive and non-destructive mapping of subsurface states and properties. However, non-uniqueness associated with the inversion process prevents the quantitative use of these methods. One major direction researchers are going is constraining the inverse problem by hydrological observations and models. An alternative to the commonly used direct inversion methods are global optimization schemes (such as genetic algorithms and Monte Carlo Markov Chain methods). However, the major limitation here is the desired high resolution of the tomographic image, which leads to a large number of parameters and an unreasonably high computational effort when using global optimization schemes. Two innovative schemes are presented here. First, a hierarchical approach is used to reduce the computational effort for the global optimization. Solution is achieved for coarse spatial resolution, and this solution is used as the starting point for finer scheme. We show that the computational effort is reduced in this way dramatically. Second, we use a direct ERT inversion as the starting point for global optimization. In this case preliminary results show that the outcome is not necessarily beneficial, probably because of spatial mismatch between the results of the direct inversion and the true resistivity field.

  3. A Hierarchical Analysis of Environmental Attitudes.

    ERIC Educational Resources Information Center

    Richmond, James M.; Baumgart, Neil

    1981-01-01

    Reported is a reanalysis of responses of a survey of environmental attitudes of English high school students. The purpose of the analysis was to try to determine if there was a hierarchical relationship among the items. Relationships were identified. (RH)

  4. Hierarchically Structured Nanomaterials for Electrochemical Energy Conversion.

    PubMed

    Trogadas, Panagiotis; Ramani, Vijay; Strasser, Peter; Fuller, Thomas F; Coppens, Marc-Olivier

    2016-01-01

    Hierarchical nanomaterials are highly suitable as electrocatalysts and electrocatalyst supports in electrochemical energy conversion devices. The intrinsic kinetics of an electrocatalyst are associated with the nanostructure of the active phase and the support, while the overall properties are also affected by the mesostructure. Therefore, both structures need to be controlled. A comparative state-of-the-art review of catalysts and supports is provided along with detailed synthesis methods. To further improve the design of these hierarchical nanomaterials, in-depth research on the effect of materials architecture on reaction and transport kinetics is necessary. Inspiration can be derived from nature, which is full of very effective hierarchical structures. Developing fundamental understanding of how desired properties of biological systems are related to their hierarchical architecture can guide the development of novel catalytic nanomaterials and nature-inspired electrochemical devices. PMID:26549054

  5. Hierarchically UVO patterned elastomeric and thermoplastic structures

    NASA Astrophysics Data System (ADS)

    Chen, Ying; Kulkarni, Manish; Marshall, Allan; Karim, Alamgir

    2014-03-01

    We demonstrate a simple yet versatile method to fabricate tunable hierarchical micro-nanostructures on flexible Poly(dimethylsiloxane) (PDMS) elastomer and thermoplastic polymer surface by a two-step process. Nanoscale patterned PDMS was obtained by imprinting compact disc (CD)/digital video disc (DVD) patterns. The second micro pattern was superposed by selective densification of PDMS by exposing to ultraviolet-ozone radiation (UVO) through micro-patterned TEM grid as a mask. The nanoscale patterns are preserved through UVO exposure step leading to formation of deep hierarchical patterns, so that for a 19 um square mesh, the micro pattern has a depth of 600nm with 6h PDMS UVO exposure time. This simple method can be promoted to fabricate hierarchical structures of thermoplastic materials (such as polystyrene), from which the mechanism of capillary imprinting and thermal stability of hierarchical patterns are investigated. This study is potentially important to various applications ranging from biomimetic scaffolds to solar cell.

  6. Hierarchically sculptured plant surfaces and superhydrophobicity.

    PubMed

    Koch, Kerstin; Bohn, Holger Florian; Barthlott, Wilhelm

    2009-12-15

    More than 400 million years of evolution of land plants led to a high diversity of adapted surface structures. Superhydrophobic biological surfaces are of special interest for the development of biomimetic materials for self-cleaning, drag reduction, and energy conservation. The key innovation in superhydrophobic biological surfaces is hierarchical sculpturing. In plants, a hydrophobic wax coating creates water-repelling surfaces that in combination with two or more levels of sculpturing leads to superhydrophobicity. Hierarchical structuring is of special interest for technical "biomimetic" materials with low adhesion and self-cleaning properties. Here we introduce hierarchical surface sculptures of plants with up to six levels. The article gives an overview of the composition of hierarchical surfaces for superhydrophobicity and their use as models for the development of artificial self-cleaning or drag-reducing surfaces. PMID:19634871

  7. Hierarchical mutual information for the comparison of hierarchical community structures in complex networks.

    PubMed

    Perotti, Juan Ignacio; Tessone, Claudio Juan; Caldarelli, Guido

    2015-12-01

    The quest for a quantitative characterization of community and modular structure of complex networks produced a variety of methods and algorithms to classify different networks. However, it is not clear if such methods provide consistent, robust, and meaningful results when considering hierarchies as a whole. Part of the problem is the lack of a similarity measure for the comparison of hierarchical community structures. In this work we give a contribution by introducing the hierarchical mutual information, which is a generalization of the traditional mutual information and makes it possible to compare hierarchical partitions and hierarchical community structures. The normalized version of the hierarchical mutual information should behave analogously to the traditional normalized mutual information. Here the correct behavior of the hierarchical mutual information is corroborated on an extensive battery of numerical experiments. The experiments are performed on artificial hierarchies and on the hierarchical community structure of artificial and empirical networks. Furthermore, the experiments illustrate some of the practical applications of the hierarchical mutual information, namely the comparison of different community detection methods and the study of the consistency, robustness, and temporal evolution of the hierarchical modular structure of networks. PMID:26764762

  8. Hierarchical mutual information for the comparison of hierarchical community structures in complex networks

    NASA Astrophysics Data System (ADS)

    Perotti, Juan Ignacio; Tessone, Claudio Juan; Caldarelli, Guido

    2015-12-01

    The quest for a quantitative characterization of community and modular structure of complex networks produced a variety of methods and algorithms to classify different networks. However, it is not clear if such methods provide consistent, robust, and meaningful results when considering hierarchies as a whole. Part of the problem is the lack of a similarity measure for the comparison of hierarchical community structures. In this work we give a contribution by introducing the hierarchical mutual information, which is a generalization of the traditional mutual information and makes it possible to compare hierarchical partitions and hierarchical community structures. The normalized version of the hierarchical mutual information should behave analogously to the traditional normalized mutual information. Here the correct behavior of the hierarchical mutual information is corroborated on an extensive battery of numerical experiments. The experiments are performed on artificial hierarchies and on the hierarchical community structure of artificial and empirical networks. Furthermore, the experiments illustrate some of the practical applications of the hierarchical mutual information, namely the comparison of different community detection methods and the study of the consistency, robustness, and temporal evolution of the hierarchical modular structure of networks.

  9. A hierarchical, ontology-driven Bayesian concept for ubiquitous medical environments--a case study for pulmonary diseases.

    PubMed

    Maragoudakis, Manolis; Lymberopoulos, Dimitrios; Fakotakis, Nikos; Spiropoulos, Kostas

    2008-01-01

    The present paper extends work on an existing computer-based Decision Support System (DSS) that aims to provide assistance to physicians as regards to pulmonary diseases. The extension deals with allowing for a hierarchical decomposition of the task, at different levels of domain granularity, using a novel approach, i.e. Hierarchical Bayesian Networks. The proposed framework uses data from various networking appliances such as mobile phones and wireless medical sensors to establish a ubiquitous environment for medical treatment of pulmonary diseases. Domain knowledge is encoded at the upper levels of the hierarchy, thus making the process of generalization easier to accomplish. The experimental results were carried out under the Pulmonary Department, University Regional Hospital Patras, Patras, Greece. They have supported our initial beliefs about the ability of Bayesian networks to provide an effective, yet semantically-oriented, means of prognosis and reasoning under conditions of uncertainty. PMID:19163541

  10. Wireless communication and their mathematics

    NASA Astrophysics Data System (ADS)

    Komaki, Shozo

    2015-05-01

    Mobile phone and smart phone are penetrating into social use. To develop these system, various type of theoretical works based on mathematics are done, such as radio propagation theory, traffic theory, security coding and wireless device etc. In this speech, I will mention about the related mathematics and problems in it.

  11. Socially Aware Heterogeneous Wireless Networks.

    PubMed

    Kosmides, Pavlos; Adamopoulou, Evgenia; Demestichas, Konstantinos; Theologou, Michael; Anagnostou, Miltiades; Rouskas, Angelos

    2015-01-01

    The development of smart cities has been the epicentre of many researchers' efforts during the past decade. One of the key requirements for smart city networks is mobility and this is the reason stable, reliable and high-quality wireless communications are needed in order to connect people and devices. Most research efforts so far, have used different kinds of wireless and sensor networks, making interoperability rather difficult to accomplish in smart cities. One common solution proposed in the recent literature is the use of software defined networks (SDNs), in order to enhance interoperability among the various heterogeneous wireless networks. In addition, SDNs can take advantage of the data retrieved from available sensors and use them as part of the intelligent decision making process contacted during the resource allocation procedure. In this paper, we propose an architecture combining heterogeneous wireless networks with social networks using SDNs. Specifically, we exploit the information retrieved from location based social networks regarding users' locations and we attempt to predict areas that will be crowded by using specially-designed machine learning techniques. By recognizing possible crowded areas, we can provide mobile operators with recommendations about areas requiring datacell activation or deactivation. PMID:26110402

  12. Wireless transmission by plasmonic antennas

    NASA Astrophysics Data System (ADS)

    Merlo, Juan M.; Calm, Yitzi M.; Rose, Aaron H.; Burns, Michael J.; Naughton, Michael J.

    Radio frequency (RF) communication is fundamental to many modern technologies. The idea of a simple rescaling of RF theory to the visible frequency range is not a direct issue, due in part to the finite conductivity in the optical range of commonly-used metals (e.g. Ag, Au). In this context, wireless communication using plasmonic antennas is a very recent concept with potential importance in an on-chip technology application. Here, we propose a plasmonic antenna system capable of wireless transmission-at-a-distance equivalent to at least four free-space wavelengths from the emitter. We demonstrate that it is possible to transmit information with maximum signal strength of -6.9 dB at three free-space wavelengths with a signal-to-noise ratio of -13 dB, good enough to be considered as an efficient wireless system. Theoretical calculations agree with our experimental results and open the possibility to future optimizations of the proposed plasmonic wireless system.

  13. Breaking Free with Wireless Networks.

    ERIC Educational Resources Information Center

    Fleischman, John

    2002-01-01

    Discusses wireless local area networks (LANs) which typically consist of laptop computers that connect to fixed access points via infrared or radio signals. Topics include wide area networks; personal area networks; problems, including limitations of available bandwidth, interference, and security concerns; use in education; interoperability;…

  14. Gigabit Wireless for Network Connectivity

    ERIC Educational Resources Information Center

    Schoedel, Eric

    2009-01-01

    Uninterrupted, high-bandwidth network connectivity is crucial for higher education. Colleges and universities increasingly adopt gigabit wireless solutions because of their fiber-equivalent performance, quick implementation, and significant return on investment. For just those reasons, Rush University Medical Center switched from free space optics…

  15. Underwater optical wireless communication network

    NASA Astrophysics Data System (ADS)

    Arnon, Shlomi

    2010-01-01

    The growing need for underwater observation and subsea monitoring systems has stimulated considerable interest in advancing the enabling technologies of underwater wireless communication and underwater sensor networks. This communication technology is expected to play an important role in investigating climate change, in monitoring biological, biogeochemical, evolutionary, and ecological changes in the sea, ocean, and lake environments, and in helping to control and maintain oil production facilities and harbors using unmanned underwater vehicles (UUVs), submarines, ships, buoys, and divers. However, the present technology of underwater acoustic communication cannot provide the high data rate required to investigate and monitor these environments and facilities. Optical wireless communication has been proposed as the best alternative to meet this challenge. Models are presented for three kinds of optical wireless communication links: (a) a line-of-sight link, (b) a modulating retroreflector link, and (c) a reflective link, all of which can provide the required data rate. We analyze the link performance based on these models. From the analysis, it is clear that as the water absorption increases, the communication performance decreases dramatically for the three link types. However, by using the scattered light it was possible to mitigate this decrease in some cases. It is concluded from the analysis that a high-data-rate underwater optical wireless network is a feasible solution for emerging applications such as UUV-to-UUV links and networks of sensors, and extended ranges in these applications could be achieved by applying a multi-hop concept.

  16. Socially Aware Heterogeneous Wireless Networks

    PubMed Central

    Kosmides, Pavlos; Adamopoulou, Evgenia; Demestichas, Konstantinos; Theologou, Michael; Anagnostou, Miltiades; Rouskas, Angelos

    2015-01-01

    The development of smart cities has been the epicentre of many researchers’ efforts during the past decade. One of the key requirements for smart city networks is mobility and this is the reason stable, reliable and high-quality wireless communications are needed in order to connect people and devices. Most research efforts so far, have used different kinds of wireless and sensor networks, making interoperability rather difficult to accomplish in smart cities. One common solution proposed in the recent literature is the use of software defined networks (SDNs), in order to enhance interoperability among the various heterogeneous wireless networks. In addition, SDNs can take advantage of the data retrieved from available sensors and use them as part of the intelligent decision making process contacted during the resource allocation procedure. In this paper, we propose an architecture combining heterogeneous wireless networks with social networks using SDNs. Specifically, we exploit the information retrieved from location based social networks regarding users’ locations and we attempt to predict areas that will be crowded by using specially-designed machine learning techniques. By recognizing possible crowded areas, we can provide mobile operators with recommendations about areas requiring datacell activation or deactivation. PMID:26110402

  17. The Wireless Student & the Library.

    ERIC Educational Resources Information Center

    Drew, Bill

    2002-01-01

    Describes a program at the State University of New York College of Agriculture and Technology at Morrisville (SUNY-Morrisville) developed with IBM called ThinkPad University that integrates computers into the teaching and learning environment. Explains a partnership with Raytheon that provides wireless connectivity; and discusses changes in…

  18. Hierarchical Nanoceramics for Industrial Process Sensors

    SciTech Connect

    Ruud, James, A.; Brosnan, Kristen, H.; Striker, Todd; Ramaswamy, Vidya; Aceto, Steven, C.; Gao, Yan; Willson, Patrick, D.; Manoharan, Mohan; Armstrong, Eric, N., Wachsman, Eric, D.; Kao, Chi-Chang

    2011-07-15

    This project developed a robust, tunable, hierarchical nanoceramics materials platform for industrial process sensors in harsh-environments. Control of material structure at multiple length scales from nano to macro increased the sensing response of the materials to combustion gases. These materials operated at relatively high temperatures, enabling detection close to the source of combustion. It is anticipated that these materials can form the basis for a new class of sensors enabling widespread use of efficient combustion processes with closed loop feedback control in the energy-intensive industries. The first phase of the project focused on materials selection and process development, leading to hierarchical nanoceramics that were evaluated for sensing performance. The second phase focused on optimizing the materials processes and microstructures, followed by validation of performance of a prototype sensor in a laboratory combustion environment. The objectives of this project were achieved by: (1) synthesizing and optimizing hierarchical nanostructures; (2) synthesizing and optimizing sensing nanomaterials; (3) integrating sensing functionality into hierarchical nanostructures; (4) demonstrating material performance in a sensing element; and (5) validating material performance in a simulated service environment. The project developed hierarchical nanoceramic electrodes for mixed potential zirconia gas sensors with increased surface area and demonstrated tailored electrocatalytic activity operable at high temperatures enabling detection of products of combustion such as NOx close to the source of combustion. Methods were developed for synthesis of hierarchical nanostructures with high, stable surface area, integrated catalytic functionality within the structures for gas sensing, and demonstrated materials performance in harsh lab and combustion gas environments.

  19. Deployable Wireless Camera Penetrators

    NASA Technical Reports Server (NTRS)

    Badescu, Mircea; Jones, Jack; Sherrit, Stewart; Wu, Jiunn Jeng

    2008-01-01

    A lightweight, low-power camera dart has been designed and tested for context imaging of sampling sites and ground surveys from an aerobot or an orbiting spacecraft in a microgravity environment. The camera penetrators also can be used to image any line-of-sight surface, such as cliff walls, that is difficult to access. Tethered cameras to inspect the surfaces of planetary bodies use both power and signal transmission lines to operate. A tether adds the possibility of inadvertently anchoring the aerobot, and requires some form of station-keeping capability of the aerobot if extended examination time is required. The new camera penetrators are deployed without a tether, weigh less than 30 grams, and are disposable. They are designed to drop from any altitude with the boost in transmitting power currently demonstrated at approximately 100-m line-of-sight. The penetrators also can be deployed to monitor lander or rover operations from a distance, and can be used for surface surveys or for context information gathering from a touch-and-go sampling site. Thanks to wireless operation, the complexity of the sampling or survey mechanisms may be reduced. The penetrators may be battery powered for short-duration missions, or have solar panels for longer or intermittent duration missions. The imaging device is embedded in the penetrator, which is dropped or projected at the surface of a study site at 90 to the surface. Mirrors can be used in the design to image the ground or the horizon. Some of the camera features were tested using commercial "nanny" or "spy" camera components with the charge-coupled device (CCD) looking at a direction parallel to the ground. Figure 1 shows components of one camera that weighs less than 8 g and occupies a volume of 11 cm3. This camera could transmit a standard television signal, including sound, up to 100 m. Figure 2 shows the CAD models of a version of the penetrator. A low-volume array of such penetrator cameras could be deployed from an

  20. Hazmat Cam Wireless Video System

    SciTech Connect

    Kevin L. Young

    2006-02-01

    This paper describes the Hazmat Cam Wireless Video System and its application to emergency response involving chemical, biological or radiological contamination. The Idaho National Laboratory designed the Hazmat Cam Wireless Video System to assist the National Guard Weapons of Mass Destruction - Civil Support Teams during their mission of emergency response to incidents involving weapons of mass destruction. The lightweight, handheld camera transmits encrypted, real-time video from inside a contaminated area, or hot-zone, to a command post located a safe distance away. The system includes a small wireless video camera, a true-diversity receiver, viewing console, and an optional extension link that allows the command post to be placed up to five miles from danger. It can be fully deployed by one person in a standalone configuration in less than 10 minutes. The complete system is battery powered. Each rechargeable camera battery powers the camera for 3 hours with the receiver and video monitor battery lasting 22 hours on a single charge. The camera transmits encrypted, low frequency analog video signals to a true-diversity receiver with three antennas. This unique combination of encryption and transmission technologies delivers encrypted, interference-free images to the command post under conditions where other wireless systems fail. The lightweight camera is completely waterproof for quick and easy decontamination after use. The Hazmat Cam Wireless Video System is currently being used by several National Guard Teams, the US Army, and by fire fighters. The system has been proven to greatly enhance situational awareness during the crucial, initial phase of a hazardous response allowing commanders to make better, faster, safer decisions.

  1. 7 tesla T2*-weighted MRI as a tool to improve detection of focal cortical dysplasia.

    PubMed

    Veersema, Tim J; van Eijsden, Pieter; Gosselaar, Peter H; Hendrikse, Jeroen; Zwanenburg, Jaco J M; Spliet, Wim G M; Aronica, Eleonora; Braun, Kees P J; Ferrier, Cyrille H

    2016-09-01

    Focal cortical dysplasia is one of the most common underlying pathologies in patients who undergo surgery for refractory epilepsy. Absence of a MRI-visible lesion necessitates additional diagnostic tests and is a predictor of poor surgical outcome. We describe a series of six patients with refractory epilepsy due to histopathologically-confirmed focal cortical dysplasia, for whom pre-surgical 7 tesla T2*-weighted MRI was acquired. In four of six patients, T2* sequences showed areas of marked superficial hypointensity, co-localizing with the epileptogenic lesion. 7 tesla T2* hypointensities overlying focal cortical dysplasia may represent leptomeningeal venous vascular abnormalities associated with the underlying dysplastic cortex. Adding T2* sequences to the MRI protocol may aid in the detection of focal cortical dysplasias. PMID:27435411

  2. A high-field (30 Tesla) pulsed magnet instrument for single-crystal scattering studies

    NASA Astrophysics Data System (ADS)

    Islam, Zahirul; Nojiri, Hiroyuki; Narumi, Yasuo; Lang, Jonathan

    2010-03-01

    Pulsed magnets have emerged as a viable approach at synchrotron x-ray facilities for studying materials in high magnetic fields. We are developing a new high-field (30 Tesla) pulsed magnet system for single-crystal x-ray diffraction studies. It consists of a single 18mm-bore solenoid, designed and built at Tohoku University using high-tensile-strength and high conductivity CuAg wires. A dual-cryostat scheme has been developed at Advanced Photon Source in order to cool the coil using liquid nitrogen and the sample using a closed-cycle cryostat independently. Liquid nitrogen cooling allows repetition rate of a few minutes for peak fields near 30 Tesla. This scheme is unique in that it allows the applied magnetic field to be parallel to the scattering plane. Time-resolved scattering data are typically collected using a fast one-dimensional strip detector. Opportunities and challenges for experiments and instrumentation will be discussed.

  3. Design study of steady-state 30-tesla liquid-neon-cooled magnet

    NASA Technical Reports Server (NTRS)

    Prok, G. M.; Brown, G. V.

    1976-01-01

    A design for a 30-tesla, liquid-neon-cooled magnet was reported which is capable of continuous operation. Cooled by nonboiling, forced-convection heat transfer to liquid neon flowing at 2.8 cu m/min in a closed, pressurized heat-transfer loop and structurally supported by a tapered structural ribbon, the tape-wound coils with a high-purity-aluminum conductor will produce over 30 teslas for 1 minute at 850 kilowatts. The magnet will have an inside diameter of 7.5 centimeters and an outside diameter of 54 centimeters. The minimum current density at design field will be 15.7 kA/sq cm.

  4. Hierarchical model for distributed seismicity.

    PubMed

    Tejedor, Alejandro; Gómez, Javier B; Pacheco, Amalio F

    2010-07-01

    A cellular automata model for the interaction between seismic faults in an extended region is presented. Faults are represented by boxes formed by a different number of sites and located in the nodes of a fractal tree. Both the distribution of box sizes and the interaction between them is assumed to be hierarchical. Load particles are randomly added to the system, simulating the action of external tectonic forces. These particles fill the sites of the boxes progressively. When a box is full it topples, some of the particles are redistributed to other boxes and some of them are lost. A box relaxation simulates the occurrence of an earthquake in the region. The particle redistributions mostly occur upwards (to larger faults) and downwards (to smaller faults) in the hierarchy producing new relaxations. A simple and efficient bookkeeping of the information allows the running of systems with more than fifty million faults. This model is consistent with the definition of magnitude, i.e., earthquakes of magnitude m take place in boxes with a number of sites ten times bigger than those boxes responsible for earthquakes with a magnitude m-1 which are placed in the immediate lower level of the hierarchy. The three parameters of the model have a geometrical nature: the height or number of levels of the fractal tree, the coordination of the tree and the ratio of areas between boxes in two consecutive levels. Besides reproducing several seismicity properties and regularities, this model is used to test the performance of some precursory patterns. PMID:20866700

  5. NUCLEAR PHYSICS: The First Nine-Cell TESLA Cavity Made in China

    NASA Astrophysics Data System (ADS)

    Lu, Xiang-Yang; Quan, Sheng-Wen; Zhang, Bao-Cheng; Hao, Jian-Kui; Zhu, Feng; Lin, Lin; Xu, Wen-Can; Wang, Er-Dong; Wang, Fang; Jin, Song; Xin, Tian-Mu; Yao, Zhong-Yuan; Chen, Jia-Er; Zhao, Kui

    2008-11-01

    A totally home-made 9-cell TESLA type superconducting cavity is made at Peking University. The cavity fabrication is according to DESY specification. The cavity is made of high purity niobium from OTIC, Ningxia. The electron beam welding is carried out at Harbin Institute of Technology, Harbin. By the cooperation, the cavity is tested at Thomas Jefferson National Accelerator Facility, USA. The preliminary result shows the acceleration gradient Eacc is 23MV/m without quench and has potential for improvement.

  6. A modified post damping ring bunch compressor beamline for the TESLA linear collider

    SciTech Connect

    Philippe R.-G. Piot; Winfried Decking

    2004-03-23

    We propose a modified bunch compressor beamline, downstream of the damping ring, for the TESLA linear collider. This modified beamline uses a third harmonic radio-frequency section based on the 3.9 GHz superconducting cavity under development at Fermilab. In our design the beam deceleration is about {approx}50 MeV instead of {approx}450 MeV in the original design proposed.

  7. Assessment of MRI Issues at 3 Tesla for a New Metallic Tissue Marker

    PubMed Central

    Cronenweth, Charlotte M.; Shellock, Frank G.

    2015-01-01

    Purpose. To assess the MRI issues at 3 Tesla for a metallic tissue marker used to localize removal areas of tissue abnormalities. Materials and Methods. A newly designed, metallic tissue marker (Achieve Marker, CareFusion, Vernon Hills, IL) used to mark biopsy sites, particularly in breasts, was assessed for MRI issues which included standardized tests to determine magnetic field interactions (i.e., translational attraction and torque), MRI-related heating, and artifacts at 3 Tesla. Temperature changes were determined for the marker using a gelled-saline-filled phantom. MRI was performed at a relatively high specific absorption rate (whole body averaged SAR, 2.9-W/kg). MRI artifacts were evaluated using T1-weighted, spin echo and gradient echo pulse sequences. Results. The marker displayed minimal magnetic field interactions (2-degree deflection angle and no torque). MRI-related heating was only 0.1°C above background heating (i.e., the heating without the tissue marker present). Artifacts seen as localized signal loss were relatively small in relation to the size and shape of the marker. Conclusions. Based on the findings, the new metallic tissue marker is acceptable or “MR Conditional” (using current labeling terminology) for a patient undergoing an MRI procedure at 3 Tesla or less. PMID:26266051

  8. An 8-GW long-pulse generator based on Tesla transformer and pulse forming network.

    PubMed

    Su, Jiancang; Zhang, Xibo; Li, Rui; Zhao, Liang; Sun, Xu; Wang, Limin; Zeng, Bo; Cheng, Jie; Wang, Ying; Peng, Jianchang; Song, Xiaoxin

    2014-06-01

    A long-pulse generator TPG700L based on a Tesla transformer and a series pulse forming network (PFN) is constructed to generate intense electron beams for the purpose of high power microwave (HPM) generation. The TPG700L mainly consists of a 12-stage PFN, a built-in Tesla transformer in a pulse forming line, a three-electrode gas switch, a transmission line with a trigger, and a load. The Tesla transformer and the compact PFN are the key technologies for the development of the TPG700L. This generator can output electrical pulses with a width as long as 200 ns at a level of 8 GW and a repetition rate of 50 Hz. When used to drive a relative backward wave oscillator for HPM generation, the electrical pulse width is about 100 ns on a voltage level of 520 kV. Factors affecting the pulse waveform of the TPG700L are also discussed. At present, the TPG700L performs well for long-pulse HPM generation in our laboratory. PMID:24985810

  9. A Tesla-type repetitive nanosecond pulse generator for solid dielectric breakdown research.

    PubMed

    Zhao, Liang; Pan, Ya Feng; Su, Jian Cang; Zhang, Xi Bo; Wang, Li Min; Fang, Jin Peng; Sun, Xu; Lui, Rui

    2013-10-01

    A Tesla-type repetitive nanosecond pulse generator including a pair of electrode and a matched absorption resistor is established for the application of solid dielectric breakdown research. As major components, a built-in Tesla transformer and a gas-gap switch are designed to boost and shape the output pulse, respectively; the electrode is to form the anticipated electric field; the resistor is parallel to the electrode to absorb the reflected energy from the test sample. The parameters of the generator are a pulse width of 10 ns, a rise and fall time of 3 ns, and a maximum amplitude of 300 kV. By modifying the primary circuit of the Tesla transformer, the generator can produce both positive and negative pulses at a repetition rate of 1-50 Hz. In addition, a real-time measurement and control system is established based on the solid dielectric breakdown requirements for this generator. With this system, experiments on test samples made of common insulation materials in pulsed power systems are conducted. The preliminary experimental results show that the constructed generator is capable to research the solid dielectric breakdown phenomenon on a nanosecond time scale. PMID:24182170

  10. 7-Tesla MRI demonstrates absence of structural lesions in patients with vestibular paroxysmia.

    PubMed

    Rommer, Paulus S; Wiest, Gerald; Kronnerwetter, Claudia; Zach, Heidemarie; Loader, Benjamin; Elwischger, Kirsten; Trattnig, Siegfried

    2015-01-01

    Vestibular parxoysmia (VP) is a rare vestibular disorder. A neurovascular cross-compression (NVCC) between the vestibulochochlear nerve and an artery seems to be responsible for short attacks of vertigo in this entity. An NVCC can be seen in up to every fourth subject. The significance of these findings is not clear, as not all subjects suffer from symptoms. The aim of the present study was to assess possible structural lesions of the vestibulocochlear nerve by means of high field magnetic resonance imaging (MRI), and whether high field MRI may help to differentiate symptomatic from asymptomatic subjects. 7 Tesla MRI was performed in six patients with VP and confirmed NVCC seen on 1.5 and 3.0 MRI. No structural abnormalities were detected in any of the patients in 7 Tesla MRI. These findings imply that high field MRI does not help to differentiate between symptomatic and asymptomatic NVCC and that the symptoms of VP are not caused by structural nerve lesions. This supports the hypothesis that the nystagmus associated with VP has to be conceived pathophysiologically as an excitatory vestibular phenomenon, being not related to vestibular hypofunction. 7 Tesla MRI outperforms conventional MRI in image resolution and may be useful in vestibular disorders. PMID:26106306

  11. 7-Tesla MRI demonstrates absence of structural lesions in patients with vestibular paroxysmia

    PubMed Central

    Rommer, Paulus S.; Wiest, Gerald; Kronnerwetter, Claudia; Zach, Heidemarie; Loader, Benjamin; Elwischger, Kirsten; Trattnig, Siegfried

    2015-01-01

    Vestibular parxoysmia (VP) is a rare vestibular disorder. A neurovascular cross-compression (NVCC) between the vestibulochochlear nerve and an artery seems to be responsible for short attacks of vertigo in this entity. An NVCC can be seen in up to every fourth subject. The significance of these findings is not clear, as not all subjects suffer from symptoms. The aim of the present study was to assess possible structural lesions of the vestibulocochlear nerve by means of high field magnetic resonance imaging (MRI), and whether high field MRI may help to differentiate symptomatic from asymptomatic subjects. 7 Tesla MRI was performed in six patients with VP and confirmed NVCC seen on 1.5 and 3.0 MRI. No structural abnormalities were detected in any of the patients in 7 Tesla MRI. These findings imply that high field MRI does not help to differentiate between symptomatic and asymptomatic NVCC and that the symptoms of VP are not caused by structural nerve lesions. This supports the hypothesis that the nystagmus associated with VP has to be conceived pathophysiologically as an excitatory vestibular phenomenon, being not related to vestibular hypofunction. 7 Tesla MRI outperforms conventional MRI in image resolution and may be useful in vestibular disorders. PMID:26106306

  12. Construction of TAMU3: A 14 Tesla Nb3Sn Model Dipole

    NASA Astrophysics Data System (ADS)

    Holik, Eddie; Blackburn, Raymond; Diaczenko, Nick; Elliott, Tim; Jaisle, Andrew; McInturff, Alfred; McIntyre, Peter; Sattarov, Dior

    2010-10-01

    The third phase of the Texas A&M University Accelerator Research Lab's ``Stress-Managed'' high field magnet campaign has coil modules for the assembly of TAMU3. The third phase is the high field, Bmax >= 12 -- 14 Tesla, proof of principle test of the ``Stress-Managed'' coil fabrication design philosophy. Earlier dipole phases operated in the 5 -- 8 Tesla range using NbTi and early bronze (ITER) Nb3Sn based superconductor. These third phase dipole winding modules use the tin rich multi-filament Nb3Sn/Cu composite strand with its enhanced engineering current density therefore have the possibility of producing magnetic fields > 14 Tesla, when combined with the evolution of much higher efficiency insulation. There are five modules under construction altogether, which are at various stages. The best performing pair during testing of these modules will comprise the upper and lower modules of TAMU4, a 4x2 cm aperture accelerator prototype dipole. There has also been progress in the fabrication and measurement techniques necessary to validate more accurately the ``Stress-Management'' approach.

  13. An 8-GW long-pulse generator based on Tesla transformer and pulse forming network

    NASA Astrophysics Data System (ADS)

    Su, Jiancang; Zhang, Xibo; Li, Rui; Zhao, Liang; Sun, Xu; Wang, Limin; Zeng, Bo; Cheng, Jie; Wang, Ying; Peng, Jianchang; Song, Xiaoxin

    2014-06-01

    A long-pulse generator TPG700L based on a Tesla transformer and a series pulse forming network (PFN) is constructed to generate intense electron beams for the purpose of high power microwave (HPM) generation. The TPG700L mainly consists of a 12-stage PFN, a built-in Tesla transformer in a pulse forming line, a three-electrode gas switch, a transmission line with a trigger, and a load. The Tesla transformer and the compact PFN are the key technologies for the development of the TPG700L. This generator can output electrical pulses with a width as long as 200 ns at a level of 8 GW and a repetition rate of 50 Hz. When used to drive a relative backward wave oscillator for HPM generation, the electrical pulse width is about 100 ns on a voltage level of 520 kV. Factors affecting the pulse waveform of the TPG700L are also discussed. At present, the TPG700L performs well for long-pulse HPM generation in our laboratory.

  14. A Tesla-type repetitive nanosecond pulse generator for solid dielectric breakdown research

    NASA Astrophysics Data System (ADS)

    Zhao, Liang; Pan, Ya Feng; Su, Jian Cang; Zhang, Xi Bo; Wang, Li Min; Fang, Jin Peng; Sun, Xu; Lui, Rui

    2013-10-01

    A Tesla-type repetitive nanosecond pulse generator including a pair of electrode and a matched absorption resistor is established for the application of solid dielectric breakdown research. As major components, a built-in Tesla transformer and a gas-gap switch are designed to boost and shape the output pulse, respectively; the electrode is to form the anticipated electric field; the resistor is parallel to the electrode to absorb the reflected energy from the test sample. The parameters of the generator are a pulse width of 10 ns, a rise and fall time of 3 ns, and a maximum amplitude of 300 kV. By modifying the primary circuit of the Tesla transformer, the generator can produce both positive and negative pulses at a repetition rate of 1-50 Hz. In addition, a real-time measurement and control system is established based on the solid dielectric breakdown requirements for this generator. With this system, experiments on test samples made of common insulation materials in pulsed power systems are conducted. The preliminary experimental results show that the constructed generator is capable to research the solid dielectric breakdown phenomenon on a nanosecond time scale.

  15. An 8-GW long-pulse generator based on Tesla transformer and pulse forming network

    SciTech Connect

    Su, Jiancang; Zhang, Xibo; Li, Rui; Zhao, Liang Sun, Xu; Wang, Limin; Zeng, Bo; Cheng, Jie; Wang, Ying; Peng, Jianchang; Song, Xiaoxin

    2014-06-15

    A long-pulse generator TPG700L based on a Tesla transformer and a series pulse forming network (PFN) is constructed to generate intense electron beams for the purpose of high power microwave (HPM) generation. The TPG700L mainly consists of a 12-stage PFN, a built-in Tesla transformer in a pulse forming line, a three-electrode gas switch, a transmission line with a trigger, and a load. The Tesla transformer and the compact PFN are the key technologies for the development of the TPG700L. This generator can output electrical pulses with a width as long as 200 ns at a level of 8 GW and a repetition rate of 50 Hz. When used to drive a relative backward wave oscillator for HPM generation, the electrical pulse width is about 100 ns on a voltage level of 520 kV. Factors affecting the pulse waveform of the TPG700L are also discussed. At present, the TPG700L performs well for long-pulse HPM generation in our laboratory.

  16. Wireless optical links for avionics applications

    NASA Astrophysics Data System (ADS)

    Chan, Eric; Koshinz, Dennis; Krug, William; Hager, Harold

    2011-06-01

    Recently there has been strong interest in wireless optical (WO) communication link applications in airplanes and avionics platforms for size, weight, power, cost, and electromagnetic interference (EMI) reduction. Wireless optical link has additional advantage of providing network security because the optical signal from wireless optical link is well confined within an airplane or avionics vehicle. In this paper we discuss some potential wireless optical link applications in commercial airplanes and the challenges in the implementation of wireless optical links for these applications. We will present our experimental results on using white LED (WLED), visible laser source and free-space small-form-factor (SFF) optical transceivers to demonstrate the viability of applying wireless optical links in avionics platforms.

  17. Performance Analysis of IIUM Wireless Campus Network

    NASA Astrophysics Data System (ADS)

    Abd Latif, Suhaimi; Masud, Mosharrof H.; Anwar, Farhat

    2013-12-01

    International Islamic University Malaysia (IIUM) is one of the leading universities in the world in terms of quality of education that has been achieved due to providing numerous facilities including wireless services to every enrolled student. The quality of this wireless service is controlled and monitored by Information Technology Division (ITD), an ISO standardized organization under the university. This paper aims to investigate the constraints of wireless campus network of IIUM. It evaluates the performance of the IIUM wireless campus network in terms of delay, throughput and jitter. QualNet 5.2 simulator tool has employed to measure these performances of IIUM wireless campus network. The observation from the simulation result could be one of the influencing factors in improving wireless services for ITD and further improvement.

  18. 75 FR 8400 - In the Matter of Certain Wireless Communications System Server Software, Wireless Handheld...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-24

    ... and Battery Packs; Notice of Investigation AGENCY: U.S. International Trade Commission. ACTION... server software, wireless handheld devices and battery packs by reason of infringement of certain claims... importation of certain wireless communications system server software, wireless handheld devices or...

  19. Wireless Sensor Needs Defined by SBIR Topics

    NASA Technical Reports Server (NTRS)

    Studor, George F.

    2010-01-01

    This slide presentation reviews the needs for wireless sensor technology from various U.S. government agencies as exhibited by an analysis of Small Business Innovation Research (SBIR) solicitations. It would appear that a multi-agency group looking at overlapping wireless sensor needs and technology projects is desired. Included in this presentation is a review of the NASA SBIR process, and an examination of some of the SBIR projects from NASA, and other agencies that involve wireless sensor development

  20. Statistical label fusion with hierarchical performance models

    PubMed Central

    Asman, Andrew J.; Dagley, Alexander S.; Landman, Bennett A.

    2014-01-01

    Label fusion is a critical step in many image segmentation frameworks (e.g., multi-atlas segmentation) as it provides a mechanism for generalizing a collection of labeled examples into a single estimate of the underlying segmentation. In the multi-label case, typical label fusion algorithms treat all labels equally – fully neglecting the known, yet complex, anatomical relationships exhibited in the data. To address this problem, we propose a generalized statistical fusion framework using hierarchical models of rater performance. Building on the seminal work in statistical fusion, we reformulate the traditional rater performance model from a multi-tiered hierarchical perspective. This new approach provides a natural framework for leveraging known anatomical relationships and accurately modeling the types of errors that raters (or atlases) make within a hierarchically consistent formulation. Herein, we describe several contributions. First, we derive a theoretical advancement to the statistical fusion framework that enables the simultaneous estimation of multiple (hierarchical) performance models within the statistical fusion context. Second, we demonstrate that the proposed hierarchical formulation is highly amenable to the state-of-the-art advancements that have been made to the statistical fusion framework. Lastly, in an empirical whole-brain segmentation task we demonstrate substantial qualitative and significant quantitative improvement in overall segmentation accuracy. PMID:24817809

  1. Hierarchical regression for analyses of multiple outcomes.

    PubMed

    Richardson, David B; Hamra, Ghassan B; MacLehose, Richard F; Cole, Stephen R; Chu, Haitao

    2015-09-01

    In cohort mortality studies, there often is interest in associations between an exposure of primary interest and mortality due to a range of different causes. A standard approach to such analyses involves fitting a separate regression model for each type of outcome. However, the statistical precision of some estimated associations may be poor because of sparse data. In this paper, we describe a hierarchical regression model for estimation of parameters describing outcome-specific relative rate functions and associated credible intervals. The proposed model uses background stratification to provide flexible control for the outcome-specific associations of potential confounders, and it employs a hierarchical "shrinkage" approach to stabilize estimates of an exposure's associations with mortality due to different causes of death. The approach is illustrated in analyses of cancer mortality in 2 cohorts: a cohort of dioxin-exposed US chemical workers and a cohort of radiation-exposed Japanese atomic bomb survivors. Compared with standard regression estimates of associations, hierarchical regression yielded estimates with improved precision that tended to have less extreme values. The hierarchical regression approach also allowed the fitting of models with effect-measure modification. The proposed hierarchical approach can yield estimates of association that are more precise than conventional estimates when one wishes to estimate associations with multiple outcomes. PMID:26232395

  2. Self-assembled biomimetic superhydrophobic hierarchical arrays.

    PubMed

    Yang, Hongta; Dou, Xuan; Fang, Yin; Jiang, Peng

    2013-09-01

    Here, we report a simple and inexpensive bottom-up technology for fabricating superhydrophobic coatings with hierarchical micro-/nano-structures, which are inspired by the binary periodic structure found on the superhydrophobic compound eyes of some insects (e.g., mosquitoes and moths). Binary colloidal arrays consisting of exemplary large (4 and 30 μm) and small (300 nm) silica spheres are first assembled by a scalable Langmuir-Blodgett (LB) technology in a layer-by-layer manner. After surface modification with fluorosilanes, the self-assembled hierarchical particle arrays become superhydrophobic with an apparent water contact angle (CA) larger than 150°. The throughput of the resulting superhydrophobic coatings with hierarchical structures can be significantly improved by templating the binary periodic structures of the LB-assembled colloidal arrays into UV-curable fluoropolymers by a soft lithography approach. Superhydrophobic perfluoroether acrylate hierarchical arrays with large CAs and small CA hysteresis can be faithfully replicated onto various substrates. Both experiments and theoretical calculations based on the Cassie's dewetting model demonstrate the importance of the hierarchical structure in achieving the final superhydrophobic surface states. PMID:23786830

  3. Analysis hierarchical model for discrete event systems

    NASA Astrophysics Data System (ADS)

    Ciortea, E. M.

    2015-11-01

    The This paper presents the hierarchical model based on discrete event network for robotic systems. Based on the hierarchical approach, Petri network is analysed as a network of the highest conceptual level and the lowest level of local control. For modelling and control of complex robotic systems using extended Petri nets. Such a system is structured, controlled and analysed in this paper by using Visual Object Net ++ package that is relatively simple and easy to use, and the results are shown as representations easy to interpret. The hierarchical structure of the robotic system is implemented on computers analysed using specialized programs. Implementation of hierarchical model discrete event systems, as a real-time operating system on a computer network connected via a serial bus is possible, where each computer is dedicated to local and Petri model of a subsystem global robotic system. Since Petri models are simplified to apply general computers, analysis, modelling, complex manufacturing systems control can be achieved using Petri nets. Discrete event systems is a pragmatic tool for modelling industrial systems. For system modelling using Petri nets because we have our system where discrete event. To highlight the auxiliary time Petri model using transport stream divided into hierarchical levels and sections are analysed successively. Proposed robotic system simulation using timed Petri, offers the opportunity to view the robotic time. Application of goods or robotic and transmission times obtained by measuring spot is obtained graphics showing the average time for transport activity, using the parameters sets of finished products. individually.

  4. Hierarchical Ensemble Methods for Protein Function Prediction

    PubMed Central

    2014-01-01

    Protein function prediction is a complex multiclass multilabel classification problem, characterized by multiple issues such as the incompleteness of the available annotations, the integration of multiple sources of high dimensional biomolecular data, the unbalance of several functional classes, and the difficulty of univocally determining negative examples. Moreover, the hierarchical relationships between functional classes that characterize both the Gene Ontology and FunCat taxonomies motivate the development of hierarchy-aware prediction methods that showed significantly better performances than hierarchical-unaware “flat” prediction methods. In this paper, we provide a comprehensive review of hierarchical methods for protein function prediction based on ensembles of learning machines. According to this general approach, a separate learning machine is trained to learn a specific functional term and then the resulting predictions are assembled in a “consensus” ensemble decision, taking into account the hierarchical relationships between classes. The main hierarchical ensemble methods proposed in the literature are discussed in the context of existing computational methods for protein function prediction, highlighting their characteristics, advantages, and limitations. Open problems of this exciting research area of computational biology are finally considered, outlining novel perspectives for future research. PMID:25937954

  5. Wireless magnetothermal deep brain stimulation.

    PubMed

    Chen, Ritchie; Romero, Gabriela; Christiansen, Michael G; Mohr, Alan; Anikeeva, Polina

    2015-03-27

    Wireless deep brain stimulation of well-defined neuronal populations could facilitate the study of intact brain circuits and the treatment of neurological disorders. Here, we demonstrate minimally invasive and remote neural excitation through the activation of the heat-sensitive capsaicin receptor TRPV1 by magnetic nanoparticles. When exposed to alternating magnetic fields, the nanoparticles dissipate heat generated by hysteresis, triggering widespread and reversible firing of TRPV1(+) neurons. Wireless magnetothermal stimulation in the ventral tegmental area of mice evoked excitation in subpopulations of neurons in the targeted brain region and in structures receiving excitatory projections. The nanoparticles persisted in the brain for over a month, allowing for chronic stimulation without the need for implants and connectors. PMID:25765068

  6. [Wireless human body communication technology].

    PubMed

    Sun, Lei; Zhang, Xiaojuan

    2014-12-01

    The Wireless Body Area Network (WBAN) is a key part of the wearable monitoring technologies, which has many communication technologies to choose from, like Bluetooth, ZigBee, Ultra Wideband, and Wireless Human Body Communication (WHBC). As for the WHBC developed in recent years, it is worthy to be further studied. The WHBC has a strong momentum of growth and a natural advantage in the formation of WBAN. In this paper, we first briefly describe the technical background of WHBC, then introduce theoretical model of human-channel communication and digital transmission machine based on human channel. And finally we analyze various of the interference of the WHBC and show the AFH (Adaptive Frequency Hopping) technology which can effectively deal with the interference. PMID:25868265

  7. Biomedical Wireless Ambulatory Crew Monitor

    NASA Technical Reports Server (NTRS)

    Chmiel, Alan; Humphreys, Brad

    2009-01-01

    A compact, ambulatory biometric data acquisition system has been developed for space and commercial terrestrial use. BioWATCH (Bio medical Wireless and Ambulatory Telemetry for Crew Health) acquires signals from biomedical sensors using acquisition modules attached to a common data and power bus. Several slots allow the user to configure the unit by inserting sensor-specific modules. The data are then sent real-time from the unit over any commercially implemented wireless network including 802.11b/g, WCDMA, 3G. This system has a distributed computing hierarchy and has a common data controller on each sensor module. This allows for the modularity of the device along with the tailored ability to control the cards using a relatively small master processor. The distributed nature of this system affords the modularity, size, and power consumption that betters the current state of the art in medical ambulatory data acquisition. A new company was created to market this technology.

  8. Wireless Augmented Reality Communication System

    NASA Technical Reports Server (NTRS)

    Devereaux, Ann (Inventor); Jedrey, Thomas (Inventor); Agan, Martin (Inventor)

    2014-01-01

    The system of the present invention is a highly integrated radio communication system with a multimedia co-processor which allows true two-way multimedia (video, audio, data) access as well as real-time biomedical monitoring in a pager-sized portable access unit. The system is integrated in a network structure including one or more general purpose nodes for providing a wireless-to-wired interface. The network architecture allows video, audio and data (including biomedical data) streams to be connected directly to external users and devices. The portable access units may also be mated to various non-personal devices such as cameras or environmental sensors for providing a method for setting up wireless sensor nets from which reported data may be accessed through the portable access unit. The reported data may alternatively be automatically logged at a remote computer for access and viewing through a portable access unit, including the user's own.

  9. Wireless augmented reality communication system

    NASA Technical Reports Server (NTRS)

    Devereaux, Ann (Inventor); Jedrey, Thomas (Inventor); Agan, Martin (Inventor)

    2006-01-01

    The system of the present invention is a highly integrated radio communication system with a multimedia co-processor which allows true two-way multimedia (video, audio, data) access as well as real-time biomedical monitoring in a pager-sized portable access unit. The system is integrated in a network structure including one or more general purpose nodes for providing a wireless-to-wired interface. The network architecture allows video, audio and data (including biomedical data) streams to be connected directly to external users and devices. The portable access units may also be mated to various non-personal devices such as cameras or environmental sensors for providing a method for setting up wireless sensor nets from which reported data may be accessed through the portable access unit. The reported data may alternatively be automatically logged at a remote computer for access and viewing through a portable access unit, including the user's own.

  10. Wireless autonomous device data transmission

    NASA Technical Reports Server (NTRS)

    Sammel, Jr., David W. (Inventor); Cain, James T. (Inventor); Mickle, Marlin H. (Inventor); Mi, Minhong (Inventor)

    2013-01-01

    A method of communicating information from a wireless autonomous device (WAD) to a base station. The WAD has a data element having a predetermined profile having a total number of sequenced possible data element combinations. The method includes receiving at the WAD an RF profile transmitted by the base station that includes a triggering portion having a number of pulses, wherein the number is at least equal to the total number of possible data element combinations. The method further includes keeping a count of received pulses and wirelessly transmitting a piece of data, preferably one bit, to the base station when the count reaches a value equal to the stored data element's particular number in the sequence. Finally, the method includes receiving the piece of data at the base station and using the receipt thereof to determine which of the possible data element combinations the stored data element is.

  11. Self-Powered Wireless Sensors

    NASA Technical Reports Server (NTRS)

    Dynys, Fred; Sayir, Ali

    2008-01-01

    NASA's integrated vehicle health management (IVHM) program offers the potential to improve aeronautical safety, reduce cost and improve performance by utilizing networks of wireless sensors. Development of sensor systems for engine hot sections will provide real-time data for prognostics and health management of turbo-engines. Sustainable power to embedded wireless sensors is a key challenge for prolong operation. Harvesting energy from the environment has emerged as a viable technique for power generation. Thermoelectric generators provide a direct conversion of heat energy to electrical energy. Micro-power sources derived from thermoelectric films are desired for applications in harsh thermal environments. Silicon based alloys are being explored for applications in high temperature environments containing oxygen. Chromium based p-type Si/Ge alloys exhibit Seebeck coefficients on the order of 160 micro V/K and low thermal conductance of 2.5 to 5 W/mK. Thermoelectric properties of bulk and thin film silicides will be discussed

  12. Wireless communication devices and movement monitoring methods

    DOEpatents

    Skorpik, James R.

    2006-10-31

    Wireless communication devices and movement monitoring methods are described. In one aspect, a wireless communication device includes a housing, wireless communication circuitry coupled with the housing and configured to communicate wireless signals, movement circuitry coupled with the housing and configured to provide movement data regarding movement sensed by the movement circuitry, and event processing circuitry coupled with the housing and the movement circuitry, wherein the event processing circuitry is configured to process the movement data, and wherein at least a portion of the event processing circuitry is configured to operate in a first operational state having a different power consumption rate compared with a second operational state.

  13. Semantic wireless body area networks.

    PubMed

    Nimmala, Venkatarama S R; Penders, Julien; van Hyfte, Dirk; Brands, Michael; Gyselinckx, Bert

    2008-01-01

    In this paper we introduce the concept of semantic Wireless Body Area Network (sWBAN). First the method for semantic interpretation of body sensor data is developed. This method is then illustrated for the case of ECG monitoring, providing the user with real-time monitoring and interpretation of heart activity. Finally, possible extensions of the method to data fusion and context-aware monitoring are discussed. PMID:19163441

  14. Space Shuttle Wireless Crew Communications

    NASA Technical Reports Server (NTRS)

    Armstrong, R. W.; Doe, R. A.

    1982-01-01

    The design, development, and performance characteristics of the Space Shuttle's Wireless Crew Communications System are discussed. This system allows Space Shuttle crews to interface with the onboard audio distribution system without the need for communications umbilicals, and has been designed through the adaptation of commercially available hardware in order to minimize development time. Testing aboard the Space Shuttle Orbiter Columbia has revealed no failures or design deficiencies.

  15. Freshness-preserving non-interactive hierarchical key agreement protocol over WHMS.

    PubMed

    Kim, Hyunsung

    2014-01-01

    The digitization of patient health information (PHI) for wireless health monitoring systems (WHMSs) has brought many benefits and challenges for both patients and physicians. However, security, privacy and robustness have remained important challenges for WHMSs. Since the patient's PHI is sensitive and the communication channel, i.e., the Internet, is insecure, it is important to protect them against unauthorized entities, i.e., attackers. Otherwise, failure to do so will not only lead to the compromise of a patient's privacy, but will also put his/her life at risk. This paper proposes a freshness-preserving non-interactive hierarchical key agreement protocol (FNKAP) for WHMSs. The FNKAP is based on the concept of the non-interactive identity-based key agreement for communication efficiency. It achieves patient anonymity between a patient and physician, session key secrecy and resistance against various security attacks, especially including replay attacks. PMID:25513824

  16. Freshness-Preserving Non-Interactive Hierarchical Key Agreement Protocol over WHMS

    PubMed Central

    Kim, Hyunsung

    2014-01-01

    The digitization of patient health information (PHI) for wireless health monitoring systems (WHMSs) has brought many benefits and challenges for both patients and physicians. However, security, privacy and robustness have remained important challenges for WHMSs. Since the patient's PHI is sensitive and the communication channel, i.e., the Internet, is insecure, it is important to protect them against unauthorized entities, i.e., attackers. Otherwise, failure to do so will not only lead to the compromise of a patient's privacy, but will also put his/her life at risk. This paper proposes a freshness-preserving non-interactive hierarchical key agreement protocol (FNKAP) for WHMSs. The FNKAP is based on the concept of the non-interactive identity-based key agreement for communication efficiency. It achieves patient anonymity between a patient and physician, session key secrecy and resistance against various security attacks, especially including replay attacks. PMID:25513824

  17. Superoleophobic Surfaces Obtained via Hierarchical Metallic Meshes.

    PubMed

    Grynyov, Roman; Bormashenko, Edward; Whyman, Gene; Bormashenko, Yelena; Musin, Albina; Pogreb, Roman; Starostin, Anton; Valtsifer, Viktor; Strelnikov, Vladimir; Schechter, Alex; Kolagatla, Srikanth

    2016-05-01

    Hierarchical metallic surfaces demonstrating pronounced water and oil repellence are reported. The surfaces were manufactured with stainless-steel microporous meshes, which were etched with perfluorononanoic acid. As a result, a hierarchical relief was created, characterized by roughness at micro- and sub-microscales. Pronounced superoleophobicity was registered with regard to canola, castor, sesame, flax, crude (petroleum), and engine oils. Relatively high sliding angles were recorded for 5 μL turpentine, olive, and silicone oil droplets. The stability of the Cassie-like air trapping wetting state, established with water/ethanol solutions, is reported. The omniphobicity of the surfaces is due to the interplay of their hierarchical relief and surface fluorination. PMID:27077637

  18. Hierarchical Micro-Nano Coatings by Painting

    NASA Astrophysics Data System (ADS)

    Kirveslahti, Anna; Korhonen, Tuulia; Suvanto, Mika; Pakkanen, Tapani A.

    2016-03-01

    In this paper, the wettability properties of coatings with hierarchical surface structures and low surface energy were studied. Hierarchically structured coatings were produced by using hydrophobic fumed silica nanoparticles and polytetrafluoroethylene (PTFE) microparticles as additives in polyester (PES) and polyvinyldifluoride (PVDF). These particles created hierarchical micro-nano structures on the paint surfaces and lowered or supported the already low surface energy of the paint. Two standard application techniques for paint application were employed and the presented coatings are suitable for mass production and use in large surface areas. By regulating the particle concentrations, it was possible to modify wettability properties gradually. Highly hydrophobic surfaces were achieved with the highest contact angle of 165∘. Dynamic contact angle measurements were carried out for a set of selected samples and low hysteresis was obtained. Produced coatings possessed long lasting durability in the air and in underwater conditions.

  19. Optimal retesting configurations for hierarchical group testing

    PubMed Central

    Black, Michael S.; Bilder, Christopher R.; Tebbs, Joshua M.

    2014-01-01

    SUMMARY Hierarchical group testing is widely used to test individuals for diseases. This testing procedure works by first amalgamating individual specimens into groups for testing. Groups testing negatively have their members declared negative. Groups testing positively are subsequently divided into smaller subgroups and are then retested to search for positive individuals. In our paper, we propose a new class of informative retesting procedures for hierarchical group testing that acknowledges heterogeneity among individuals. These procedures identify the optimal number of groups and their sizes at each testing stage in order to minimize the expected number of tests. We apply our proposals in two settings: 1) HIV testing programs that currently use three-stage hierarchical testing and 2) chlamydia and gonorrhea screening practices that currently use individual testing. For both applications, we show that substantial savings can be realized by our new procedures. PMID:26166904

  20. A hierarchical cellular logic for pyramid computers

    SciTech Connect

    Tanimoto, S.L.

    1984-11-01

    Hierarchical structure occurs in biological vision systems and there is good reason to incorporate it into a model of computation for processing binary images. A mathematical formalism is presented which can describe a wide variety of operations useful in image processing and graphics. The formalism allows for two kinds of simple transformations on the values (called pyramids) of a set of cells called a hierarchical domain: the first are binary operations on boolean values, and the second are neighborhood-matching operations. The implied model of computation is more structured than previously discussed pyramidal models, and is more readily realized in parallel hardware, while it remains sufficiently rich to provide efficient solutions to a wide variety of problems. The model has a simplicity which is due to the restricted nature of the operations and the implied synchronization across the hierarchical domain. A corresponding algebraic simplicity in the logic makes possible the concise representation of many cellular-data operations.

  1. Hierarchical bioinspired adhesive surfaces-a review.

    PubMed

    Brodoceanu, D; Bauer, C T; Kroner, E; Arzt, E; Kraus, T

    2016-01-01

    The extraordinary adherence and climbing agility of geckos on rough surfaces has been attributed to the multiscale hierarchical structures on their feet. Hundreds of thousands of elastic hairs called setae, each of which split into several spatulae, create a large number of contact points that generate substantial adhesion through van der Waals interactions. The hierarchical architecture provides increased structural compliance on surfaces with roughness features ranging from micrometers to millimeters. We review synthetic adhesion surfaces that mimic the naturally occurring hierarchy with an emphasis on microfabrication strategies, material choice and the adhesive performance achieved. PMID:27529743

  2. Hierarchical Analysis of the Omega Ontology

    SciTech Connect

    Joslyn, Cliff A.; Paulson, Patrick R.

    2009-12-01

    Initial delivery for mathematical analysis of the Omega Ontology. We provide an analysis of the hierarchical structure of a version of the Omega Ontology currently in use within the US Government. After providing an initial statistical analysis of the distribution of all link types in the ontology, we then provide a detailed order theoretical analysis of each of the four main hierarchical links present. This order theoretical analysis includes the distribution of components and their properties, their parent/child and multiple inheritance structure, and the distribution of their vertical ranks.

  3. Hierarchical social networks and information flow

    NASA Astrophysics Data System (ADS)

    López, Luis; F. F. Mendes, Jose; Sanjuán, Miguel A. F.

    2002-12-01

    Using a simple model for the information flow on social networks, we show that the traditional hierarchical topologies frequently used by companies and organizations, are poorly designed in terms of efficiency. Moreover, we prove that this type of structures are the result of the individual aim of monopolizing as much information as possible within the network. As the information is an appropriate measurement of centrality, we conclude that this kind of topology is so attractive for leaders, because the global influence each actor has within the network is completely determined by the hierarchical level occupied.

  4. Interface fluctuations on a hierarchical lattice

    NASA Astrophysics Data System (ADS)

    Iglói, Ferenc; Szalma, Ferenc

    1996-08-01

    We consider interface fluctuations on a two-dimensional layered lattice where the couplings follow a hierarchical sequence. This problem is equivalent to the diffusion process of a quantum particle in the presence of a one-dimensional hierarchical potential. According to a modified Harris criterion, this type of perturbation is relevant and one expects anomalous fluctuating behavior. By transfer-matrix techniques and by an exact renormalization-group transformation we have obtained analytical results for the interface fluctuation exponents, which are discontinuous at the homogeneous lattice limit.

  5. Hierarchical assembly of diphenylalanine into dendritic nanoarchitectures.

    PubMed

    Han, Tae Hee; Oh, Jun Kyun; Lee, Gyoung-Ja; Pyun, Su-Il; Kim, Sang Ouk

    2010-09-01

    Highly ordered, multi-dimensional dendritic nanoarchitectures were created via self-assembly of diphenylalanine from an acidic buffer solution. The self-similarity of dendritic structures was characterized by examining their fractal dimensions with the box-counting method. The fractal dimension was determined to be 1.7, which demonstrates the fractal dimension of structures generated by diffusion limited aggregation on a two-dimensional substrate surface. By confining the dendritic assembly of diphenylalanine within PDMS microchannels, the self-similar dendritic growth could be hierarchically directed to create linearly assembled nanoarchitectures. Our approach offers a novel pathway for creating and directing hierarchical nanoarchitecture from biomolecular assembly. PMID:20605423

  6. On the Feasibility of Wireless Multimedia Sensor Networks over IEEE 802.15.5 Mesh Topologies

    PubMed Central

    Garcia-Sanchez, Antonio-Javier; Losilla, Fernando; Rodenas-Herraiz, David; Cruz-Martinez, Felipe; Garcia-Sanchez, Felipe

    2016-01-01

    Wireless Multimedia Sensor Networks (WMSNs) are a special type of Wireless Sensor Network (WSN) where large amounts of multimedia data are transmitted over networks composed of low power devices. Hierarchical routing protocols typically used in WSNs for multi-path communication tend to overload nodes located within radio communication range of the data collection unit or data sink. The battery life of these nodes is therefore reduced considerably, requiring frequent battery replacement work to extend the operational life of the WSN system. In a wireless sensor network with mesh topology, any node may act as a forwarder node, thereby enabling multiple routing paths toward any other node or collection unit. In addition, mesh topologies have proven advantages, such as data transmission reliability, network robustness against node failures, and potential reduction in energy consumption. This work studies the feasibility of implementing WMSNs in mesh topologies and their limitations by means of exhaustive computer simulation experiments. To this end, a module developed for the Synchronous Energy Saving (SES) mode of the IEEE 802.15.5 mesh standard has been integrated with multimedia tools to thoroughly test video sequences encoded using H.264 in mesh networks. PMID:27164106

  7. On the Feasibility of Wireless Multimedia Sensor Networks over IEEE 802.15.5 Mesh Topologies.

    PubMed

    Garcia-Sanchez, Antonio-Javier; Losilla, Fernando; Rodenas-Herraiz, David; Cruz-Martinez, Felipe; Garcia-Sanchez, Felipe

    2016-01-01

    Wireless Multimedia Sensor Networks (WMSNs) are a special type of Wireless Sensor Network (WSN) where large amounts of multimedia data are transmitted over networks composed of low power devices. Hierarchical routing protocols typically used in WSNs for multi-path communication tend to overload nodes located within radio communication range of the data collection unit or data sink. The battery life of these nodes is therefore reduced considerably, requiring frequent battery replacement work to extend the operational life of the WSN system. In a wireless sensor network with mesh topology, any node may act as a forwarder node, thereby enabling multiple routing paths toward any other node or collection unit. In addition, mesh topologies have proven advantages, such as data transmission reliability, network robustness against node failures, and potential reduction in energy consumption. This work studies the feasibility of implementing WMSNs in mesh topologies and their limitations by means of exhaustive computer simulation experiments. To this end, a module developed for the Synchronous Energy Saving (SES) mode of the IEEE 802.15.5 mesh standard has been integrated with multimedia tools to thoroughly test video sequences encoded using H.264 in mesh networks. PMID:27164106

  8. Decentralized System Identification Using Stochastic Subspace Identification for Wireless Sensor Networks

    PubMed Central

    Cho, Soojin; Park, Jong-Woong; Sim, Sung-Han

    2015-01-01

    Wireless sensor networks (WSNs) facilitate a new paradigm to structural identification and monitoring for civil infrastructure. Conventional structural monitoring systems based on wired sensors and centralized data acquisition systems are costly for installation as well as maintenance. WSNs have emerged as a technology that can overcome such difficulties, making deployment of a dense array of sensors on large civil structures both feasible and economical. However, as opposed to wired sensor networks in which centralized data acquisition and processing is common practice, WSNs require decentralized computing algorithms to reduce data transmission due to the limitation associated with wireless communication. In this paper, the stochastic subspace identification (SSI) technique is selected for system identification, and SSI-based decentralized system identification (SDSI) is proposed to be implemented in a WSN composed of Imote2 wireless sensors that measure acceleration. The SDSI is tightly scheduled in the hierarchical WSN, and its performance is experimentally verified in a laboratory test using a 5-story shear building model. PMID:25856325

  9. Wireless Laptops and Local Area Networks.

    ERIC Educational Resources Information Center

    Tolson, Stephanie Diane

    2001-01-01

    Describes experiences at St. Louis Community College at Florissant Valley (Missouri) with the use of wireless technology and a local area network for library bibliographic instruction. Discusses faculty input and attitudes; technical challenges; and experiences at other community colleges that have found wireless connections more economical than…

  10. Home and School Technology: Wired versus Wireless.

    ERIC Educational Resources Information Center

    Van Horn, Royal

    2001-01-01

    Presents results of informal research on smart homes and appliances, structured home wiring, whole-house audio/video distribution, hybrid cable, and wireless networks. Computer network wiring is tricky to install unless all-in-one jacketed cable is used. Wireless phones help installers avoid pre-wiring problems in homes and schools. (MLH)

  11. Wireless power transfer to a cardiac implant

    NASA Astrophysics Data System (ADS)

    Kim, Sanghoek; Ho, John S.; Chen, Lisa Y.; Poon, Ada S. Y.

    2012-08-01

    We analyze wireless power transfer between a source and a weakly coupled implant on the heart. Numerical studies show that mid-field wireless powering achieves much higher power transfer efficiency than traditional inductively coupled systems. With proper system design, power sufficient to operate typical cardiac implants can be received by millimeter-sized coils.

  12. Tips for Implementing a Wireless Network

    ERIC Educational Resources Information Center

    Walery, Darrell

    2005-01-01

    This article provides a quick start guide to provide educators with the basic points to consider before installing a wireless network in the school. Since many school districts have already implemented wireless networks, there is a lot of information available online to assist in the process.

  13. Progressive Image Coding by Hierarchical Linear Approximation.

    ERIC Educational Resources Information Center

    Wu, Xiaolin; Fang, Yonggang

    1994-01-01

    Proposes a scheme of hierarchical piecewise linear approximation as an adaptive image pyramid. A progressive image coder comes naturally from the proposed image pyramid. The new pyramid is semantically more powerful than regular tessellation but syntactically simpler than free segmentation. This compromise between adaptability and complexity…

  14. Performance Measurement Framework for Hierarchical Text Classification.

    ERIC Educational Resources Information Center

    Sun, Aixin; Lim, Ee-Peng; Ng, Wee-Keong

    2003-01-01

    Discusses hierarchical text classification for electronic information retrieval and the measures used to evaluate performance. Proposes new performance measures that consist of category similarity measures and distance-based measures that consider the contributions of misclassified documents, and explains a blocking measure that identifies…

  15. A Hierarchical Grouping of Great Educators

    ERIC Educational Resources Information Center

    Barker, Donald G.

    1977-01-01

    Great educators of history were categorized on the basis of their: aims of education, fundamental ideas, and educational theories. They were classed by Ward's method of hierarchical analysis into six groupings: Socrates, Ausonius, Jerome, Abelard; Quintilian, Origen, Melanchthon, Ascham, Loyola; Alciun, Comenius; Vittorino, Basedow, Pestalozzi,…

  16. Hierarchical interconnection networks for multicomputer systems

    SciTech Connect

    Dandamudi, S.P. ); Eager, D.L. )

    1990-06-01

    Multicomputer systems are distributed-memory MIMD systems. Communication in these systems occurs through explicit message passing. Therefore, the underlying processor interconnection network plays an important and direct role in determining their performance. Several types f interconnection networks have been proposed. Unfortunately, no network is universally better. Ideally, therefore, systems should use more than one such network. Furthermore, systems that have large numbers of processors should be able to exploit locality in communication in order to obtain improved performance. This paper proposes the use of hierarchical interconnection networks to meet both these requirements. A performance analysis of a class of hierarchical interconnection networks is presented. This analysis includes both static analysis (queuing delays are neglected) and queuing analysis. In both cases, the hierarchical networks are shown to have better cost-benefit ratios. The queuing analysis is also validated (within our model) by several simulation experiments. The impact of two performance enhancement schemes---replication of links and improved routing algorithms---on hierarchical interconnection network performance is also presented.

  17. Hierarchical coefficient of a multifractal based network

    NASA Astrophysics Data System (ADS)

    Moreira, Darlan A.; Lucena, Liacir dos Santos; Corso, Gilberto

    2014-02-01

    The hierarchical property for a general class of networks stands for a power-law relation between clustering coefficient, CC and connectivity k: CC∝kβ. This relation is empirically verified in several biologic and social networks, as well as in random and deterministic network models, in special for hierarchical networks. In this work we show that the hierarchical property is also present in a Lucena network. To create a Lucena network we use the dual of a multifractal lattice ML, the vertices are the sites of the ML and links are established between neighbouring lattices, therefore this network is space filling and planar. Besides a Lucena network shows a scale-free distribution of connectivity. We deduce a relation for the maximal local clustering coefficient CCimax of a vertex i in a planar graph. This condition expresses that the number of links among neighbour, N△, of a vertex i is equal to its connectivity ki, that means: N△=ki. The Lucena network fulfils the condition N△≃ki independent of ki and the anisotropy of ML. In addition, CCmax implies the threshold β=1 for the hierarchical property for any scale-free planar network.

  18. Parallel temporal dynamics in hierarchical cognitive control.

    PubMed

    Ranti, Carolyn; Chatham, Christopher H; Badre, David

    2015-09-01

    Cognitive control allows us to follow abstract rules in order to choose appropriate responses given our desired outcomes. Cognitive control is often conceptualized as a hierarchical decision process, wherein decisions made at higher, more abstract levels of control asymmetrically influence lower-level decisions. These influences could evolve sequentially across multiple levels of a hierarchical decision, consistent with much prior evidence for central bottlenecks and seriality in decision-making processes. However, here, we show that multiple levels of hierarchical cognitive control are processed primarily in parallel. Human participants selected responses to stimuli using a complex, multiply contingent (third order) rule structure. A response deadline procedure allowed assessment of the accuracy and timing of decisions made at each level of the hierarchy. In contrast to a serial decision process, error rates across levels of the decision mostly declined simultaneously and at identical rates, with only a slight tendency to complete the highest level decision first. Simulations with a biologically plausible neural network model demonstrate how such parallel processing could emerge from a previously developed hierarchically nested frontostriatal architecture. Our results support a parallel processing model of cognitive control, in which uncertainty on multiple levels of a decision is reduced simultaneously. PMID:26051820

  19. A Hierarchical Process-Dissociation Model

    ERIC Educational Resources Information Center

    Rouder, Jeffrey N.; Lu, Jun; Morey, Richard D.; Sun, Dongchu; Speckman, Paul L.

    2008-01-01

    In fitting the process-dissociation model (L. L. Jacoby, 1991) to observed data, researchers aggregate outcomes across participant, items, or both. T. Curran and D. L. Hintzman (1995) demonstrated how biases from aggregation may lead to artifactual support for the model. The authors develop a hierarchical process-dissociation model that does not…

  20. Cognitive Diagnostic Analysis Using Hierarchically Structured Skills

    ERIC Educational Resources Information Center

    Su, Yu-Lan

    2013-01-01

    This dissertation proposes two modified cognitive diagnostic models (CDMs), the deterministic, inputs, noisy, "and" gate with hierarchy (DINA-H) model and the deterministic, inputs, noisy, "or" gate with hierarchy (DINO-H) model. Both models incorporate the hierarchical structures of the cognitive skills in the model estimation…

  1. Transforming Hierarchical Relationships in Student Conduct Administration

    ERIC Educational Resources Information Center

    Jacobson, Kelly A.

    2013-01-01

    Conflict transformation theory provided a philosophical lens for this critical cultural, constructivist study, wherein four student conduct administrators who engage in leveling hierarchical relationships with students in conduct processes shared ways they make meaning of their professional practice. Through informal, unstructured interviews, a…

  2. Managing Clustered Data Using Hierarchical Linear Modeling

    ERIC Educational Resources Information Center

    Warne, Russell T.; Li, Yan; McKyer, E. Lisako J.; Condie, Rachel; Diep, Cassandra S.; Murano, Peter S.

    2012-01-01

    Researchers in nutrition research often use cluster or multistage sampling to gather participants for their studies. These sampling methods often produce violations of the assumption of data independence that most traditional statistics share. Hierarchical linear modeling is a statistical method that can overcome violations of the independence…

  3. Metal oxide nanostructures with hierarchical morphology

    DOEpatents

    Ren, Zhifeng; Lao, Jing Yu; Banerjee, Debasish

    2007-11-13

    The present invention relates generally to metal oxide materials with varied symmetrical nanostructure morphologies. In particular, the present invention provides metal oxide materials comprising one or more metallic oxides with three-dimensionally ordered nanostructural morphologies, including hierarchical morphologies. The present invention also provides methods for producing such metal oxide materials.

  4. Types of Online Hierarchical Repository Structures

    ERIC Educational Resources Information Center

    Hershkovitz, Arnon; Azran, Ronit; Hardof-Jaffe, Sharon; Nachmias, Rafi

    2011-01-01

    This study presents an empirical investigation of online hierarchical repositories of items presented to university students in Web-supported course websites, using Web mining methods. To this end, data from 1747 courses were collected, and the use of online repositories of content items in these courses was examined. At a later stage, courses…

  5. Hierarchical Forms Processing in Adults and Children

    ERIC Educational Resources Information Center

    Harrison, Tamara B.; Stiles, Joan

    2009-01-01

    Two experiments examined child and adult processing of hierarchical stimuli composed of geometric forms. Adults (ages 18-23 years) and children (ages 7-10 years) performed a forced-choice task gauging similarity between visual stimuli consisting of large geometric objects (global level) composed of small geometric objects (local level). The…

  6. Rehabilitation Goals: Their Hierarchical and Multifaceted Nature.

    ERIC Educational Resources Information Center

    Livneh, Hanoch

    1988-01-01

    Rehabilitation goals are analyzed from a hierarchical, multifaceted perspective, illustrating reduction of the ultimate goal of life adjustment to smaller goals. Addressed are: the contexts within which rehabilitation takes place, the activity levels defining human performance, and the functional levels achieved. A matrix of 12 sets of goals is…

  7. Optimization of hierarchical management of technological processes

    NASA Astrophysics Data System (ADS)

    Bayas, Marcia M.; Dubovoy, B. M.; Shegebaeva, Jibek; Gromaszek, Konrad

    2015-12-01

    The advisability of clustering of control tasks providing reduction of information flows needed to coordinate operational processes is demonstrated. Criterion and algorithm for optimal aggregation are proposed. The influence of the hierarchical structure of control system on the filling factor of information flow matrix is discussed.

  8. Value of 3 Tesla diffusion-weighted magnetic resonance imaging for assessing liver fibrosis

    PubMed Central

    Papalavrentios, Lavrentios; Sinakos, Emmanouil; Chourmouzi, Danai; Hytiroglou, Prodromos; Drevelegas, Konstantinos; Constantinides, Manos; Drevelegas, Antonios; Talwalkar, Jayant; Akriviadis, Evangelos

    2015-01-01

    Background Limited data are available regarding the role of magnetic resonance imaging (MRI), particularly the new generation 3 Tesla technology, and especially diffusion-weighted imaging (DWI) in predicting liver fibrosis. The aim of our pilot study was to assess the clinical performance of the apparent diffusion coefficient (ADC) of liver parenchyma for the assessment of liver fibrosis in patients with non-alcoholic fatty liver disease (NAFLD). Methods 18 patients with biopsy-proven NAFLD underwent DWI with 3 Tesla MRI. DWI was performed with single-shot echo-planar technique at b values of 0-500 and 0-1000 s/mm2. ADC was measured in four locations in the liver and the mean ADC value was used for analysis. Staging of fibrosis was performed according to the METAVIR system. Results The median age of patients was 52 years (range 23-73). The distribution of patients in different fibrosis stages was: 0 (n=1), 1 (n=7), 2 (n=1), 3 (n=5), 4 (n=4). Fibrosis stage was poorly associated with ADC at b value of 0-500 s/mm2 (r= -0.30, P=0.27). However it was significantly associated with ADC at b value of 0-1000 s/mm2 (r= -0.57, P=0.01). For this b value (0-1000 s/mm2) the area under receiver-operating characteristic curve was 0.93 for fibrosis stage ≥3 and the optimal ADC cut-off value was 1.16 ×10-3 mm2/s. Conclusion 3 Tesla DWI can possibly predict the presence of advanced fibrosis in patients with NAFLD. PMID:25608776

  9. Evaluation of wireless data communications at KSC

    NASA Technical Reports Server (NTRS)

    Gejji, Raghvendra R.

    1995-01-01

    This project is motivated by the need for temporary or emergency provisioning of LAN service at KSC. The main goal of the project was to evaluate existing wireless bridge equipment in the KSC environment. Wireless bridge equipment can be used to make a wireless connection between two remotely located LAN segments. This report describes the experimental setup used to evaluate the equipment, including antenna connections, workstation connections, bridge software and workstation software The rangefinder program on the bridge was used to gather data about how the RF propagation environment at KSC affects the performance of the wireless bridge. Data was gathered for indoor as well as outdoor propagation. The report concludes with recommendations on how to take into account the particular terrain and building structures at KSC to design future applications of wireless bridges.

  10. Science and Technology of the TESLA Electron-Positron Linear Collider

    NASA Astrophysics Data System (ADS)

    Wagner, Albrecht

    2002-07-01

    Recent analyses of the long term future of particles physics in Asia, Europe, and the U.S.A. have led to the consensus that the next major facility to be built to unravel the secrets of the micro-cosmos is an electron-positron linear collider in the energy range of 500 to 1000 GeV. This collider should be constructed in an as timely fashion as possible to overlap with the Large Hadron Collider, under construction at CERN. Here, the scientific potential and the technological aspects of the TESLA projects, a superconducting collider with an integrated X-ray laser laboratory, are summarised.

  11. Cavity control system advanced modeling and simulations for TESLA linear accelerator and free electron laser

    NASA Astrophysics Data System (ADS)

    Czarski, Tomasz; Romaniuk, Ryszard S.; Pozniak, Krzysztof T.; Simrock, Stefan

    2004-07-01

    The cavity control system for the TESLA -- TeV-Energy Superconducting Linear Accelerator project is initially introduced. The elementary analysis of the cavity resonator on RF (radio frequency) level and low level frequency with signal and power considerations is presented. For the field vector detection the digital signal processing is proposed. The electromechanical model concerning Lorentz force detuning is applied for analyzing the basic features of the system performance. For multiple cavities driven by one klystron the field vector sum control is considered. Simulink model implementation is developed to explore the feedback and feed-forward system operation and some experimental results for signals and power considerations are presented.

  12. Experimental determination of magnetohydrodynamic seawater thruster performance in a two Tesla test facility

    SciTech Connect

    Picologlou, B.; Doss, E.; Black, D.; Sikes, W.C.

    1992-09-01

    A two Tesla test facility was designed, built, and operated to investigate the performance of magnetohydrodynamic (MHD) seawater thrusters. The results of this investigation are used to validate MHD thruster performance computer models. The facility test loop, its components, and their design are presented in detail. Additionally, the test matrix and its rational are discussed. finally, representative experimental results of the test program are presented, and are compared to pretest computer model predictions. Good agreement between predicted and measured data has served to validate the thruster performance computer models.

  13. Experimental determination of magnetohydrodynamic seawater thruster performance in a two Tesla test facility

    SciTech Connect

    Picologlou, B.; Doss, E.; Black, D. ); Sikes, W.C. )

    1992-01-01

    A two Tesla test facility was designed, built, and operated to investigate the performance of magnetohydrodynamic (MHD) seawater thrusters. The results of this investigation are used to validate MHD thruster performance computer models. The facility test loop, its components, and their design are presented in detail. Additionally, the test matrix and its rational are discussed. finally, representative experimental results of the test program are presented, and are compared to pretest computer model predictions. Good agreement between predicted and measured data has served to validate the thruster performance computer models.

  14. 3.0 Tesla magnetic resonance imaging: A new standard in liver imaging?

    PubMed Central

    Girometti, Rossano

    2015-01-01

    An ever-increasing number of 3.0 Tesla (T) magnets are installed worldwide. Moving from the standard of 1.5 T to higher field strength implies a number of potential advantage and drawbacks, requiring careful optimization of imaging protocols or implementation of novel hardware components. Clinical practice and literature review suggest that state-of-the-art 3.0 T is equivalent to 1.5 T in the assessment of focal liver lesions and diffuse liver disease. Therefore, further technical improvements are needed in order to fully exploit the potential of higher field strength. PMID:26244063

  15. Large scale Tesla coil guided discharges initiated by femtosecond laser filamentation in air

    NASA Astrophysics Data System (ADS)

    Arantchouk, L.; Point, G.; Brelet, Y.; Prade, B.; Carbonnel, J.; André, Y.-B.; Mysyrowicz, A.; Houard, A.

    2014-07-01

    The guiding of meter scale electric discharges produced in air by a Tesla coil is realized in laboratory using a focused terawatt laser pulse undergoing filamentation. The influence of the focus position, the laser arrival time, or the gap length is studied to determine the best conditions for efficient laser guiding. Discharge parameters such as delay, jitter, and resistance are characterized. An increase of the discharge length by a factor 5 has been achieved with the laser filaments, corresponding to a mean breakdown field of 2 kV/cm for a 1.8 m gap length. Consecutive guided discharges at a repetition rate of 10 Hz are also reported.

  16. Adapting TESLA technology for future cw light sources using HoBiCaT.

    PubMed

    Kugeler, O; Neumann, A; Anders, W; Knobloch, J

    2010-07-01

    The HoBiCaT facility has been set up and operated at the Helmholtz-Zentrum-Berlin and BESSY since 2005. Its purpose is testing superconducting cavities in cw mode of operation and it was successfully demonstrated that TESLA pulsed technology can be used for cw mode of operation with only minor changes. Issues that were addressed comprise of elevated dynamic thermal losses in the cavity walls, necessary modifications in the cryogenics and the cavity processing, the optimum choice of operational parameters such as cavity temperature or bandwidth, the characterization of higher order modes in the cavity, and the usability of existing tuners and couplers for cw. PMID:20687747

  17. Adapting TESLA technology for future cw light sources using HoBiCaT

    NASA Astrophysics Data System (ADS)

    Kugeler, O.; Neumann, A.; Anders, W.; Knobloch, J.

    2010-07-01

    The HoBiCaT facility has been set up and operated at the Helmholtz-Zentrum-Berlin and BESSY since 2005. Its purpose is testing superconducting cavities in cw mode of operation and it was successfully demonstrated that TESLA pulsed technology can be used for cw mode of operation with only minor changes. Issues that were addressed comprise of elevated dynamic thermal losses in the cavity walls, necessary modifications in the cryogenics and the cavity processing, the optimum choice of operational parameters such as cavity temperature or bandwidth, the characterization of higher order modes in the cavity, and the usability of existing tuners and couplers for cw.

  18. Incidental optochiasmatic cavernoma: Case report of an unusual finding on 3 Tesla MRI.

    PubMed

    Trentadue, Mirko; Pozzi Mucelli, Roberto; Piovan, Enrico; Pizzini, Francesca Benedetta

    2016-08-01

    Cavernoma is a vascular hamartoma, which represents 10-20% of all central nervous system vascular malformations. The majority (80%) of them are supratentorial, while involvement of the cranial nerves and the optic pathways is extremely rare. The main clinical presentation of optochiasmatic cavernomas consists of chiasmatic apoplexy, which is a neurosurgical emergency. Here, we report a case in which the finding was incidentally detected in a 49-year-old man. We describe the imaging characteristics of the lesion in such a rare location, highlighting the role of magnetic resonance imaging (MRI) (specifically 3 Tesla) in the management of asymptomatic patients. PMID:27145992

  19. Poly-coil design for a 60 tesla quasi-stationary magnet

    NASA Astrophysics Data System (ADS)

    Boenig, H. J.; Campbell, L. J.; Hodgdon, M. L.; Lopez, E. A.; Rickel, D. G.; Rogers, J. D.; Schillig, J. B.; Sims, J. R.; Pernambuco-Wise, P.; Schneider-Muntau, H. J.

    1993-02-01

    Among the new facilities to be offered by the National Science Foundation through the National High Magnetic Field Laboratory (NHMFL) are pulsed fields that can only be achieved at a national user facility by virtue of their strength, duration, and volume. In particular, a 44 mm bore pulsed magnet giving a 60 tesla field for 100 ms is in the final design stage. This magnet will be powered by a 1.4 GW motor-generator at Los Alamos and is an important step toward proving design principles that will be needed for the higher field quasi-stationary pulsed magnets that this power source is capable of driving.

  20. Liquid neon heat transfer as applied to a 30 tesla cryomagnet

    NASA Technical Reports Server (NTRS)

    Papell, S. S.; Hendricks, R. C.

    1975-01-01

    A 30-tesla magnet design is studied which calls for forced convection liquid neon heat transfer in small coolant channels. The design also requires suppressing boiling by subjecting the fluid to high pressures through use of magnet coils enclosed in a pressure vessel which is maintained at the critical pressure of liquid neon. This high pressure reduces the possibility of the system flow instabilities which may occur at low pressures. The forced convection heat transfer data presented were obtained by using a blowdown technique to force the fluid to flow vertically through a resistance heated, instrumented tube.

  1. 47 CFR 27.1305 - Shared wireless broadband network.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 2 2012-10-01 2012-10-01 false Shared wireless broadband network. 27.1305... MISCELLANEOUS WIRELESS COMMUNICATIONS SERVICES 700 MHz Public/Private Partnership § 27.1305 Shared wireless broadband network. The Shared Wireless Broadband Network developed by the 700 MHz Public/Private...

  2. World Without Wires: Is Your District Ready to Go Wireless?

    ERIC Educational Resources Information Center

    Villano, Matt

    2005-01-01

    In this article, the author presents the latest wireless equipments available in market. For starters, wireless networks offer mobility and flexibility: users of laptops, PDAs, tablet PCs, and wireless Voice over IP telephones can move freely about campus while staying connected to the Internet. There are two kinds of wireless networks: ad-hoc, or…

  3. Capacity Limit, Link Scheduling and Power Control in Wireless Networks

    ERIC Educational Resources Information Center

    Zhou, Shan

    2013-01-01

    The rapid advancement of wireless technology has instigated the broad deployment of wireless networks. Different types of networks have been developed, including wireless sensor networks, mobile ad hoc networks, wireless local area networks, and cellular networks. These networks have different structures and applications, and require different…

  4. Nanotribological and wetting performance of hierarchical patterns.

    PubMed

    Grewal, H S; Piao, Shuxue; Cho, Il-Joo; Jhang, Kyung-Young; Yoon, Eui-Sung

    2016-01-21

    Surface modification is a promising method to solve the tribological problems in microsystems. To modify the surface, we fabricated hierarchical patterns with different pitches of nano-scale features and different surface chemistries. Micro- and nano-patterns with similar geometrical configurations were also fabricated for comparison. The nano-tribological behavior of the patterns was investigated using an atomic force microscope at different relative humidity levels (5% to 80%) and applied normal loads (40 nN to 120 nN) under a constant sliding velocity. The results showed significant enhancement in the de-wetting and tribological performance of the hierarchical patterns compared with those of flat and micro- and nano-patterned surfaces. The PTFE-coated hierarchical patterns showed similar dynamic contact angles (advancing and receding) to those of the real lotus leaf. The influence of relative humidity on adhesion and friction behavior was found to be significant for all the tested surfaces. The tribological performance was improved as the pitch of the nano-scale geometry of the hierarchical pattern increased, even though the wetting property was not influenced significantly. A model was proposed based on the role of intermolecular force to explain the effect of the pitch of the hierarchical patterns on the adhesion and friction behavior. According to the model based on the molecular force, the contact between a ball and the patterned surface was a multi-asperity contact, contrary to the single-asperity contact predicted by the Johnson-Kendall-Roberts (JKR) and Maugis-Dugdale (MD) models. The strong intermolecular forces, which are activated in the confined spaces between the adjacent nano-pillars and the ball, contributed to the contact area and hence the adhesion and friction forces. PMID:26549103

  5. Inference and Hierarchical Modeling in the Social Sciences.

    ERIC Educational Resources Information Center

    Draper, David

    1995-01-01

    The use of hierarchical models in social science research is discussed, with emphasis on causal inference and consideration of the limitations of hierarchical models. The increased use of Gibbs sampling and other Markov-chain Monte Carlo methods in the application of hierarchical models is recommended. (SLD)

  6. Application of a hierarchical structure stochastic learning automation

    NASA Technical Reports Server (NTRS)

    Neville, R. G.; Chrystall, M. S.; Mars, P.

    1979-01-01

    A hierarchical structure automaton was developed using a two state stochastic learning automato (SLA) in a time shared model. Application of the hierarchical SLA to systems with multidimensional, multimodal performance criteria is described. Results of experiments performed with the hierarchical SLA using a performance index with a superimposed noise component of ? or - delta distributed uniformly over the surface are discussed.

  7. Incorporating Usability Criteria into the Development of Animated Hierarchical Maps

    ERIC Educational Resources Information Center

    Shih, Yu-Cheng; Huang, Pei-Ren; Chen, Sherry Y.

    2013-01-01

    Nowadays, Web-based learning systems have become popular because they can provide multiple tools, among which hierarchical maps are widely used to support teaching and learning. However, traditional hierarchical maps may let learners easily get lost within large information space. This study proposes an animated hierarchical map to address this…

  8. Wireless Luminescence Integrated Sensors (WLIS)

    SciTech Connect

    Simpson, M.L.; Sayler, G.S.

    2003-11-10

    The goal of this project was the development of a family of wireless, single-chip, luminescence-sensing devices to solve a number of difficult distributed measurement problems in areas ranging from environmental monitoring and assessment to high-throughput screening of combinatorial chemistry libraries. These wireless luminescence integrated sensors (WLIS) consist of a microluminometer, wireless data transmitter, and RF power input circuit all realized in a standard integrated circuit (IC) process with genetically engineered, whole-cell, bioluminescent bioreporters encapsulated and deposited on the IC. The end product is a family of compact, low-power, rugged, low-cost sensors. As part of this program they developed an integrated photodiode/signal-processing scheme with an rms noise level of 175 electrons/second for a 13-minute integration time, and a quantum efficiency of 66% at the 490-nm bioluminescent wavelength. this performance provided a detection limit of < 1000 photons/second. Although sol-gel has previously been used to encapsulate yeast cells, the reaction conditions necessary for polymerization (primarily low pH) have beforehand proven too harsh for bacterial cell immobilizations. Utilizing sonication methods, they have were able to initiate polymerization under pH conditions conductive to cell survival. both a toluene bioreporter (Pseudomonas putida TVA8) and a naphthalene bioreporter (Pseudomonas fluorescens HK44) were successfully encapsulated in sol-gel and shown to produce a fairly significant bioluminescent response. In addition to the previously developed naphthalene- and toluene-sensitive bioreporters, they developed a yeast-based xenoestrogen reporter. This technology has been licensed by Micro Systems Technologies, a startup company in Dayton, Ohio for applications in environmental containments monitoring, and for detecting weapons of mass destruction (i.e. homeland security).

  9. Passive wireless ultrasonic transducer systems

    NASA Astrophysics Data System (ADS)

    Zhong, C. H.; Croxford, A. J.; Wilcox, P. D.

    2014-02-01

    Inductive coupling and capacitive coupling both offer simple solutions to wirelessly probe ultrasonic transducers. This paper investigates the theory and feasibility of such system in the context of non-destructive evaluation (NDE) applications. Firstly, the physical principles and construction of an inductively coupled transducer system (ICTS) and a capacitively coupled transducer system (CCTS) are introduced. Then the development of a transmission line model with the measured impedance of a bonded piezoelectric ceramic disc representing a sensor attached to an arbitrary solid substrate for both systems is described. The models are validated experimentally. Several applications of CCTS are presented, such CCTS for the underwater and through-composite testing.

  10. Cooperative Synchronization in Wireless Networks

    NASA Astrophysics Data System (ADS)

    Etzlinger, Bernhard; Wymeersch, Henk; Springer, Andreas

    2014-06-01

    Synchronization is a key functionality in wireless network, enabling a wide variety of services. We consider a Bayesian inference framework whereby network nodes can achieve phase and skew synchronization in a fully distributed way. In particular, under the assumption of Gaussian measurement noise, we derive two message passing methods (belief propagation and mean field), analyze their convergence behavior, and perform a qualitative and quantitative comparison with a number of competing algorithms. We also show that both methods can be applied in networks with and without master nodes. Our performance results are complemented by, and compared with, the relevant Bayesian Cram\\'er-Rao bounds.

  11. Packet Controller For Wireless Headset

    NASA Technical Reports Server (NTRS)

    Christensen, Kurt K.; Swanson, Richard J.

    1993-01-01

    Packet-message controller implements communications protocol of network of wireless headsets. Designed for headset application, readily adapted to other uses; slight modification enables controller to implement Integrated Services Digital Network (ISDN) X.25 protocol, giving far-reaching applications in telecommunications. Circuit converts continuous voice signals into digital packets of data and vice versa. Operates in master or slave mode. Controller reduced to single complementary metal oxide/semiconductor integrated-circuit chip. Occupies minimal space in headset and consumes little power, extending life of headset battery.

  12. WMSA for wireless communication applications

    NASA Astrophysics Data System (ADS)

    Vats, Monika; Agarwal, Alok; Kumar, Ravindra

    2016-03-01

    Modified rectangular compact microstrip patch antenna having finite ground plane is proposed in this paper. Wideband Microstrip Antenna (WMSA) is achieved by corner cut and inserting air gaps inside the edges of the radiating patch having finite ground plane. The obtained impedance bandwidth for 10 dB return loss for the operating frequency f0 = 2.09 GHz is 28.7 % (600 MHz), which is very high as compared to the bandwidth obtained for the conventional microstrip antenna. Compactness with wide bandwidth of this antenna is practically useful for the wireless communication systems.

  13. Wireless power transfer magnetic couplers

    DOEpatents

    Wu, Hunter; Gilchrist, Aaron; Sealy, Kylee

    2016-01-19

    A magnetic coupler is disclosed for wireless power transfer systems. A ferrimagnetic component is capable of guiding a magnetic field. A wire coil is wrapped around at least a portion of the ferrimagnetic component. A screen is capable of blocking leakage magnetic fields. The screen may be positioned to cover at least one side of the ferrimagnetic component and the coil. A distance across the screen may be at least six times an air gap distance between the ferrimagnetic component and a receiving magnetic coupler.

  14. Fly-by-Wireless Update

    NASA Technical Reports Server (NTRS)

    Studor, George

    2010-01-01

    The presentation reviews what is meant by the term 'fly-by-wireless', common problems and motivation, provides recent examples, and examines NASA's future and basis for collaboration. The vision is to minimize cables and connectors and increase functionality across the aerospace industry by providing reliable, lower cost, modular, and higher performance alternatives to wired data connectivity to benefit the entire vehicle/program life-cycle. Focus areas are system engineering and integration methods to reduce cables and connectors, vehicle provisions for modularity and accessibility, and a 'tool box' of alternatives to wired connectivity.

  15. Partnership Opportunities with AFRC for Wireless Systems Flight Testing

    NASA Technical Reports Server (NTRS)

    Hang, Richard

    2015-01-01

    The presentation will overview the flight test capabilities at NASA Armstrong Flight Research Center (AFRC), to open up partnership collaboration opportunities for Wireless Community to conduct flight testing of aerospace wireless technologies. Also, it will brief the current activities on wireless sensor system at AFRC through SBIR (Small Business Innovation Research) proposals, and it will show the current areas of interest on wireless technologies that AFRC would like collaborate with Wireless Community to further and testing.

  16. In vivo sensitivity estimation and imaging acceleration with rotating RF coil arrays at 7 Tesla

    NASA Astrophysics Data System (ADS)

    Li, Mingyan; Jin, Jin; Zuo, Zhentao; Liu, Feng; Trakic, Adnan; Weber, Ewald; Zhuo, Yan; Xue, Rong; Crozier, Stuart

    2015-03-01

    Using a new rotating SENSitivity Encoding (rotating-SENSE) algorithm, we have successfully demonstrated that the rotating radiofrequency coil array (RRFCA) was capable of achieving a significant reduction in scan time and a uniform image reconstruction for a homogeneous phantom at 7 Tesla. However, at 7 Tesla the in vivo sensitivity profiles (B1-) become distinct at various angular positions. Therefore, sensitivity maps at other angular positions cannot be obtained by numerically rotating the acquired ones. In this work, a novel sensitivity estimation method for the RRFCA was developed and validated with human brain imaging. This method employed a library database and registration techniques to estimate coil sensitivity at an arbitrary angular position. The estimated sensitivity maps were then compared to the acquired sensitivity maps. The results indicate that the proposed method is capable of accurately estimating both magnitude and phase of sensitivity at an arbitrary angular position, which enables us to employ the rotating-SENSE algorithm to accelerate acquisition and reconstruct image. Compared to a stationary coil array with the same number of coil elements, the RRFCA was able to reconstruct images with better quality at a high reduction factor. It is hoped that the proposed rotation-dependent sensitivity estimation algorithm and the acceleration ability of the RRFCA will be particularly useful for ultra high field MRI.

  17. Encouraging a "Romantic Understanding" of Science: The Effect of the Nikola Tesla Story

    NASA Astrophysics Data System (ADS)

    Hadzigeorgiou, Yannis; Klassen, Stephen; Klassen, Cathrine Froese

    2012-08-01

    The purpose of this paper is to discuss and apply the notion of romantic understanding by outlining its features and its potential role in science education, to identify its features in the story of Nikola Tesla, and to describe an empirical study conducted to determine the effect of telling such a story to Grade 9 students. Elaborated features of the story are the humanization of meaning, an association with heroes and heroic qualities, the limits of reality and extremes of experience, a sense of wonder, and a contesting of conventions and conventional ideas. The study demonstrates the learning benefits of encouraging a romantic understanding through a story that is structured explicitly around the identified features, in this instance in the context of the production and transmission of alternating current electricity. Quantitative and qualitative analyses of journal entries showed that the group of students who were encouraged to understand the concept of alternating current romantically (the experimental group) became more involved with both the content and the context of the story than a comparison group of students who were taught the concept explicitly, without a context (the control group). The students in the experimental group also performed statistically better on a science-content test taken 1 week and again 8 weeks after the indicated teaching intervention. This finding, along with the content analyses of students' journals, provided evidence of romantic understanding of the science content for those students who listened to the Tesla story.

  18. In vivo sensitivity estimation and imaging acceleration with rotating RF coil arrays at 7 Tesla.

    PubMed

    Li, Mingyan; Jin, Jin; Zuo, Zhentao; Liu, Feng; Trakic, Adnan; Weber, Ewald; Zhuo, Yan; Xue, Rong; Crozier, Stuart

    2015-03-01

    Using a new rotating SENSitivity Encoding (rotating-SENSE) algorithm, we have successfully demonstrated that the rotating radiofrequency coil array (RRFCA) was capable of achieving a significant reduction in scan time and a uniform image reconstruction for a homogeneous phantom at 7 Tesla. However, at 7 Tesla the in vivo sensitivity profiles (B1(-)) become distinct at various angular positions. Therefore, sensitivity maps at other angular positions cannot be obtained by numerically rotating the acquired ones. In this work, a novel sensitivity estimation method for the RRFCA was developed and validated with human brain imaging. This method employed a library database and registration techniques to estimate coil sensitivity at an arbitrary angular position. The estimated sensitivity maps were then compared to the acquired sensitivity maps. The results indicate that the proposed method is capable of accurately estimating both magnitude and phase of sensitivity at an arbitrary angular position, which enables us to employ the rotating-SENSE algorithm to accelerate acquisition and reconstruct image. Compared to a stationary coil array with the same number of coil elements, the RRFCA was able to reconstruct images with better quality at a high reduction factor. It is hoped that the proposed rotation-dependent sensitivity estimation algorithm and the acceleration ability of the RRFCA will be particularly useful for ultra high field MRI. PMID:25635352

  19. Wakefield and RF Kicks Due to Coupler Asymmetry in TESLA-Type Accelerating Cavities

    SciTech Connect

    Bane, K.L.F.; Adolphsen, C.; Li, Z.; Dohlus, M.; Zagorodnov, I.; Gonin, I.; Lunin, A.; Solyak, N.; Yakovlev, V.; Gjonaj, E.; Weiland, T.; /Darmstadt, Tech. Hochsch.

    2008-07-07

    In a future linear collider, such as the International Linear Collider (ILC), trains of high current, low emittance bunches will be accelerated in a linac before colliding at the interaction point. Asymmetries in the accelerating cavities of the linac will generate fields that will kick the beam transversely and degrade the beam emittance and thus the collider performance. In the main linac of the ILC, which is filled with TESLA-type superconducting cavities, it is the fundamental (FM) and higher mode (HM) couplers that are asymmetric and thus the source of such kicks. The kicks are of two types: one, due to (the asymmetry in) the fundamental RF fields and the other, due to transverse wakefields that are generated by the beam even when it is on axis. In this report we calculate the strength of these kicks and estimate their effect on the ILC beam. The TESLA cavity comprises nine cells, one HM coupler in the upstream end, and one (identical, though rotated) HM coupler and one FM coupler in the downstream end (for their shapes and location see Figs. 1, 2) [1]. The cavity is 1.1 m long, the iris radius 35 mm, and the coupler beam pipe radius 39 mm. Note that the couplers reach closer to the axis than the irises, down to a distance of 30 mm.

  20. Unpowered wireless analog resistance sensor

    NASA Astrophysics Data System (ADS)

    Andringa, Matthew M.; Neikirk, Dean P.; Wood, Sharon L.

    2004-07-01

    Our society depends heavily on a network of buildings, bridges and roadways. In order to properly maintain this civil infrastructure and avoid damage and costly repairs due to structural failure, it is necessary to monitor the health of these structures. Sensors must frequently be placed in inaccessible locations under harsh conditions and should ideally last the lifetime of the structure the sensors are monitoring. This paper presents the development of a low cost, passive, un-powered wireless analog resistance sensor. The sensor was originally designed for monitoring corrosion in concrete, but there are many other potential applications including remote temperature monitoring, embedded accelerometers, and embedded strain gauges. The passive wireless nature makes the sensor ideally suited for embedding in inaccessible locations under harsh conditions. The sensor consists of a resonant inductor-capacitor circuit containing a resistive transducer. The sensor is interrogated by measuring the impedance through a remote, magnetically coupled reader loop. The width of the resonance is directly related to the resistance of the transducer. The sensor has been simulated under a variety of conditions using a circuit model and compared to actual test sensors built and evaluated in the laboratory.

  1. Wireless Augmented Reality Prototype (WARP)

    NASA Technical Reports Server (NTRS)

    Devereaux, A. S.

    1999-01-01

    Initiated in January, 1997, under NASA's Office of Life and Microgravity Sciences and Applications, the Wireless Augmented Reality Prototype (WARP) is a means to leverage recent advances in communications, displays, imaging sensors, biosensors, voice recognition and microelectronics to develop a hands-free, tetherless system capable of real-time personal display and control of computer system resources. Using WARP, an astronaut may efficiently operate and monitor any computer-controllable activity inside or outside the vehicle or station. The WARP concept is a lightweight, unobtrusive heads-up display with a wireless wearable control unit. Connectivity to the external system is achieved through a high-rate radio link from the WARP personal unit to a base station unit installed into any system PC. The radio link has been specially engineered to operate within the high- interference, high-multipath environment of a space shuttle or space station module. Through this virtual terminal, the astronaut will be able to view and manipulate imagery, text or video, using voice commands to control the terminal operations. WARP's hands-free access to computer-based instruction texts, diagrams and checklists replaces juggling manuals and clipboards, and tetherless computer system access allows free motion throughout a cabin while monitoring and operating equipment.

  2. Wireless Microstimulators for Neural Prosthetics

    PubMed Central

    Sahin, Mesut; Pikov, Victor

    2016-01-01

    One of the roadblocks in the field of neural prosthetics is the lack of microelectronic devices for neural stimulation that can last a lifetime in the central nervous system. Wireless multi-electrode arrays are being developed to improve the longevity of implants by eliminating the wire interconnects as well as the chronic tissue reactions due to the tethering forces generated by these wires. An area of research that has not been sufficiently investigated is a simple single-channel passive microstimulator that can collect the stimulus energy that is transmitted wirelessly through the tissue and immediately convert it into the stimulus pulse. For example, many neural prosthetic approaches to intraspinal microstimulation require only a few channels of stimulation. Wired spinal cord implants are not practical for human subjects because of the extensive flexions and rotations that the spinal cord experiences. Thus, intraspinal microstimulation may be a pioneering application that can benefit from submillimetersize floating stimulators. Possible means of energizing such a floating microstimulator, such as optical, acoustic, and electromagnetic waves, are discussed. PMID:21488815

  3. Evaluation of wireless Local Area Networks

    NASA Astrophysics Data System (ADS)

    McBee, Charles L.

    1993-09-01

    This thesis is an in-depth evaluation of the current wireless Local Area Network (LAN) technologies. Wireless LAN's consist of three technologies: they are infrared light, microwave, and spread spectrum. When the first wireless LAN's were introduced, they were unfavorably labeled slow, expensive, and unreliable. The wireless LAN's of today are competitively priced, more secure, easier to install, and provide equal to or greater than the data throughput of unshielded twisted pair cable. Wireless LAN's are best suited for organizations that move office staff frequently, buildings that have historical significance, or buildings that have asbestos. Additionally, an organization may realize a cost savings of between $300 to $1,200 each time a node is moved. Current wireless LAN technologies have a positive effect on LAN standards being developed by the Defense Information System Agency (DISA). DoD as a whole is beginning to focus on wireless LAN's and mobile communications. If system managers want to remain successful, they need to stay abreast of this technology.

  4. Non-contrast-enhanced MR portography and hepatic venography with time-spatial labeling inversion pulses: comparison at 1.5 Tesla and 3 Tesla

    PubMed Central

    Isoda, Hiroyoshi; Furuta, Akihiro; Togashi, Kaori

    2015-01-01

    Background A 3 Tesla (3 T) magnetic resonance (MR) scanner is a promising tool for upper abdominal MR angiography. However, there is no report focused on the image quality of non-contrast-enhanced MR portography and hepatic venography at 3 T. Purpose To compare and evaluate images of non-contrast-enhanced MR portography and hepatic venography with time-spatial labeling inversion pulses (Time-SLIP) at 1.5 Tesla (1.5 T) and 3 T. Material and Methods Twenty-five healthy volunteers were examined using respiratory-triggered three-dimensional balanced steady-state free-precession (bSSFP) with Time-SLIP. For portography, we used one tagging pulse (selective inversion recovery) and one non-selective inversion recovery pulse; for venography, two tagging pulses were used. The relative signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were quantified, and the quality of visualization was evaluated. Results The CNRs of the main portal vein, right portal vein, and left portal vein at 3 T were better than at 1.5 T. The image quality scores for the portal branches of segment 4, 5, and 8 were significantly higher at 3 T than at 1.5 T. The CNR of the right hepatic vein (RHV) at 3 T was significantly lower than at 1.5 T. The image quality scores of RHV and the middle hepatic vein were higher at 1.5 T than at 3 T. For RHV visualization, the difference was statistically significant. Conclusion Non-contrast-enhanced MR portography with Time-SLIP at 3 T significantly improved visualization of the peripheral branch in healthy volunteers compared with1.5 T. Non-contrast-enhanced MR hepatic venography at 1.5 T was better than at 3 T. PMID:26019890

  5. Sleep Deprivation Attack Detection in Wireless Sensor Network

    NASA Astrophysics Data System (ADS)

    Bhattasali, Tapalina; Chaki, Rituparna; Sanyal, Sugata

    2012-02-01

    Deployment of sensor network in hostile environment makes it mainly vulnerable to battery drainage attacks because it is impossible to recharge or replace the battery power of sensor nodes. Among different types of security threats, low power sensor nodes are immensely affected by the attacks which cause random drainage of the energy level of sensors, leading to death of the nodes. The most dangerous type of attack in this category is sleep deprivation, where target of the intruder is to maximize the power consumption of sensor nodes, so that their lifetime is minimized. Most of the existing works on sleep deprivation attack detection involve a lot of overhead, leading to poor throughput. The need of the day is to design a model for detecting intrusions accurately in an energy efficient manner. This paper proposes a hierarchical framework based on distributed collaborative mechanism for detecting sleep deprivation torture in wireless sensor network efficiently. Proposed model uses anomaly detection technique in two steps to reduce the probability of false intrusion.

  6. Particle swarm optimization for the clustering of wireless sensors

    NASA Astrophysics Data System (ADS)

    Tillett, Jason C.; Rao, Raghuveer M.; Sahin, Ferat; Rao, T. M.

    2003-07-01

    Clustering is necessary for data aggregation, hierarchical routing, optimizing sleep patterns, election of extremal sensors, optimizing coverage and resource allocation, reuse of frequency bands and codes, and conserving energy. Optimal clustering is typically an NP-hard problem. Solutions to NP-hard problems involve searches through vast spaces of possible solutions. Evolutionary algorithms have been applied successfully to a variety of NP-hard problems. We explore one such approach, Particle Swarm Optimization (PSO), an evolutionary programming technique where a 'swarm' of test solutions, analogous to a natural swarm of bees, ants or termites, is allowed to interact and cooperate to find the best solution to the given problem. We use the PSO approach to cluster sensors in a sensor network. The energy efficiency of our clustering in a data-aggregation type sensor network deployment is tested using a modified LEACH-C code. The PSO technique with a recursive bisection algorithm is tested against random search and simulated annealing; the PSO technique is shown to be robust. We further investigate developing a distributed version of the PSO algorithm for clustering optimally a wireless sensor network.

  7. EM threat analysis for wireless systems.

    SciTech Connect

    Burkholder, R. J. (Ohio State University Electroscience Laboratory); Mariano, Robert J.; Schniter, P. (Ohio State University Electroscience Laboratory); Gupta, I. J. (Ohio State University Electroscience Laboratory)

    2006-06-01

    Modern digital radio systems are complex and must be carefully designed, especially when expected to operate in harsh propagation environments. The ability to accurately predict the effects of propagation on wireless radio performance could lead to more efficient radio designs as well as the ability to perform vulnerability analyses before and after system deployment. In this report, the authors--experts in electromagnetic (EM) modeling and wireless communication theory--describe the construction of a simulation environment that is capable of quantifying the effects of wireless propagation on the performance of digital communication.

  8. Hierarchical curiosity loops and active sensing.

    PubMed

    Gordon, Goren; Ahissar, Ehud

    2012-08-01

    A curious agent acts so as to optimize its learning about itself and its environment, without external supervision. We present a model of hierarchical curiosity loops for such an autonomous active learning agent, whereby each loop selects the optimal action that maximizes the agent's learning of sensory-motor correlations. The model is based on rewarding the learner's prediction errors in an actor-critic reinforcement learning (RL) paradigm. Hierarchy is achieved by utilizing previously learned motor-sensory mapping, which enables the learning of other mappings, thus increasing the extent and diversity of knowledge and skills. We demonstrate the relevance of this architecture to active sensing using the well-studied vibrissae (whiskers) system, where rodents acquire sensory information by virtue of repeated whisker movements. We show that hierarchical curiosity loops starting from optimally learning the internal models of whisker motion and then extending to object localization result in free-air whisking and object palpation, respectively. PMID:22386787

  9. Biomimetic silicification of demineralized hierarchical collagenous tissues

    PubMed Central

    Ryou, Heonjune; Diogenes, Anibal; Yiu, Cynthia K.Y.; Mazzoni, Annalisa; Chen, Ji-hua; Arola, Dwayne D.; Hargreaves, Kenneth M.; Pashley, David H.; Tay, Franklin R.

    2013-01-01

    Unlike man-made composite materials, natural biominerals containing composites usually demonstrate different levels of sophisticated hierarchical structures which are responsible for their mechanical properties and other metabolic functions. However, the complex spatial organizations of the organic-inorganic phases are far beyond what they be achieved by contemporary engineering techniques. Here, we demonstrate that carbonated apatite present in collagen matrices derived from fish scale and bovine bone may be replaced by amorphous silica, using an approach that simulates what is utilized by phylogenetically ancient glass sponges. The structural hierarchy of these collagen-based biomaterials is replicated by the infiltration and condensation of fluidic polymer-stabilized silicic acid precursors within the intrafibrillar milieu of type I collagen fibrils. This facile biomimetic silicification strategy may be used for fabricating silica-based, three-dimensional functional materials with specific morphological and hierarchical requirements. PMID:23586938

  10. An Hierarchical approach to Big Data

    NASA Astrophysics Data System (ADS)

    Allen, Mark G.; Fernique, Pierre

    2015-08-01

    The increasing volumes of astronomical data require practical methods for data access, visualisation and analysis. Hierarchical methods based on sky tessellation techniques enable a multi-resolution approach to astronomy data from the individual pixels up to the whole sky. The Hierarchical Progressive Survey (HiPS) scheme based on the HEALPix is able to describe images, catalogues and 3-dimensional data cubes and is a practical solution for managing large volumes of heterogeneous data. We present the development of HiPS, and its implementation for ~200 diverse data sets at the CDS and other data centres. We highlight the ease of implementation and the use of HiPS with Aladin Lite and other applications.

  11. First-passage phenomena in hierarchical networks

    NASA Astrophysics Data System (ADS)

    Tavani, Flavia; Agliari, Elena

    2016-02-01

    In this paper we study Markov processes and related first-passage problems on a class of weighted, modular graphs which generalize the Dyson hierarchical model. In these networks, the coupling strength between two nodes depends on their distance and is modulated by a parameter σ . We find that, in the thermodynamic limit, ergodicity is lost and the "distant" nodes cannot be reached. Moreover, for finite-sized systems, there exists a threshold value for σ such that, when σ is relatively large, the inhomogeneity of the coupling pattern prevails and "distant" nodes are hardly reached. The same analysis is carried on also for generic hierarchical graphs, where interactions are meant to involve p -plets (p >2 ) of nodes, finding that ergodicity is still broken in the thermodynamic limit, but no threshold value for σ is evidenced, ultimately due to a slow growth of the network diameter with the size.

  12. Non-Homogeneous Fractal Hierarchical Weighted Networks

    PubMed Central

    Dong, Yujuan; Dai, Meifeng; Ye, Dandan

    2015-01-01

    A model of fractal hierarchical structures that share the property of non-homogeneous weighted networks is introduced. These networks can be completely and analytically characterized in terms of the involved parameters, i.e., the size of the original graph Nk and the non-homogeneous weight scaling factors r1, r2, · · · rM. We also study the average weighted shortest path (AWSP), the average degree and the average node strength, taking place on the non-homogeneous hierarchical weighted networks. Moreover the AWSP is scrupulously calculated. We show that the AWSP depends on the number of copies and the sum of all non-homogeneous weight scaling factors in the infinite network order limit. PMID:25849619

  13. Hierarchical networks, power laws, and neuronal avalanches

    NASA Astrophysics Data System (ADS)

    Friedman, Eric J.; Landsberg, Adam S.

    2013-03-01

    We show that in networks with a hierarchical architecture, critical dynamical behaviors can emerge even when the underlying dynamical processes are not critical. This finding provides explicit insight into current studies of the brain's neuronal network showing power-law avalanches in neural recordings, and provides a theoretical justification of recent numerical findings. Our analysis shows how the hierarchical organization of a network can itself lead to power-law distributions of avalanche sizes and durations, scaling laws between anomalous exponents, and universal functions—even in the absence of self-organized criticality or critical points. This hierarchy-induced phenomenon is independent of, though can potentially operate in conjunction with, standard dynamical mechanisms for generating power laws.

  14. Hierarchical porous polymer scaffolds from block copolymers.

    PubMed

    Sai, Hiroaki; Tan, Kwan Wee; Hur, Kahyun; Asenath-Smith, Emily; Hovden, Robert; Jiang, Yi; Riccio, Mark; Muller, David A; Elser, Veit; Estroff, Lara A; Gruner, Sol M; Wiesner, Ulrich

    2013-08-01

    Hierarchical porous polymer materials are of increasing importance because of their potential application in catalysis, separation technology, or bioengineering. Examples for their synthesis exist, but there is a need for a facile yet versatile conceptual approach to such hierarchical scaffolds and quantitative characterization of their nonperiodic pore systems. Here, we introduce a synthesis method combining well-established concepts of macroscale spinodal decomposition and nanoscale block copolymer self-assembly with porosity formation on both length scales via rinsing with protic solvents. We used scanning electron microscopy, small-angle x-ray scattering, transmission electron tomography, and nanoscale x-ray computed tomography for quantitative pore-structure characterization. The method was demonstrated for AB- and ABC-type block copolymers, and resulting materials were used as scaffolds for calcite crystal growth. PMID:23908232

  15. Hierarchical structure of the logical Internet graph

    NASA Astrophysics Data System (ADS)

    Ge, Zihui; Figueiredo, Daniel R.; Jaiswal, Sharad; Gao, Lixin

    2001-07-01

    The study of the Internet topology has recently received much attention from the research community. In particular, the observation that the network graph has interesting properties, such as power laws, that might be explored in a myriad of ways. Most of the work in characterizing the Internet graph is based on the physical network graph, i.e., the connectivity graph. In this paper we investigate how logical relationships between nodes of the AS graph can be used to gain insight to its structure. We characterize the logical graph using various metrics and identify the presence of power laws in the number of customers that a provider has. Using these logical relationships we define a structural model of the AS graph. The model highlights the hierarchical nature of logical relationships and the preferential connection to larger providers. We also investigate the consistency of this model over time and observe interesting properties of the hierarchical structure.

  16. Hierarchical Robot Control In A Multisensor Environment

    NASA Astrophysics Data System (ADS)

    Bhanu, Bir; Thune, Nils; Lee, Jih Kun; Thune, Mari

    1987-03-01

    Automatic recognition, inspection, manipulation and assembly of objects will be a common denominator in most of tomorrow's highly automated factories. These tasks will be handled by intelligent computer controlled robots with multisensor capabilities which contribute to desired flexibility and adaptability. The control of a robot in such a multisensor environment becomes of crucial importance as the complexity of the problem grows exponentially with the number of sensors, tasks, commands and objects. In this paper we present an approach which uses CAD (Computer-Aided Design) based geometric and functional models of objects together with action oriented neuroschemas to recognize and manipulate objects by a robot in a multisensor environment. The hierarchical robot control system is being implemented on a BBN Butterfly multi processor. Index terms: CAD, Hierarchical Control, Hypothesis Generation and Verification, Parallel Processing, Schemas

  17. Noise enhances information transfer in hierarchical networks.

    PubMed

    Czaplicka, Agnieszka; Holyst, Janusz A; Sloot, Peter M A

    2013-01-01

    We study the influence of noise on information transmission in the form of packages shipped between nodes of hierarchical networks. Numerical simulations are performed for artificial tree networks, scale-free Ravasz-Barabási networks as well for a real network formed by email addresses of former Enron employees. Two types of noise are considered. One is related to packet dynamics and is responsible for a random part of packets paths. The second one originates from random changes in initial network topology. We find that the information transfer can be enhanced by the noise. The system possesses optimal performance when both kinds of noise are tuned to specific values, this corresponds to the Stochastic Resonance phenomenon. There is a non-trivial synergy present for both noisy components. We found also that hierarchical networks built of nodes of various degrees are more efficient in information transfer than trees with a fixed branching factor. PMID:23390574

  18. Noise enhances information transfer in hierarchical networks

    PubMed Central

    Czaplicka, Agnieszka; Holyst, Janusz A.; Sloot, Peter M. A.

    2013-01-01

    We study the influence of noise on information transmission in the form of packages shipped between nodes of hierarchical networks. Numerical simulations are performed for artificial tree networks, scale-free Ravasz-Barabási networks as well for a real network formed by email addresses of former Enron employees. Two types of noise are considered. One is related to packet dynamics and is responsible for a random part of packets paths. The second one originates from random changes in initial network topology. We find that the information transfer can be enhanced by the noise. The system possesses optimal performance when both kinds of noise are tuned to specific values, this corresponds to the Stochastic Resonance phenomenon. There is a non-trivial synergy present for both noisy components. We found also that hierarchical networks built of nodes of various degrees are more efficient in information transfer than trees with a fixed branching factor. PMID:23390574

  19. Hierarchical Fiber Structures Made by Electrospinning Polymers

    NASA Astrophysics Data System (ADS)

    Reneker, Darrell H.

    2009-03-01

    A filter for water purification that is very thin, with small interstices and high surface area per unit mass, can be made with nanofibers. The mechanical strength of a very thin sheet of nanofibers is not great enough to withstand the pressure drop of the fluid flowing through. If the sheet of nanofibers is made thicker, the strength will increase, but the flow will be reduced to an impractical level. An optimized filter can be made with nanometer scale structures supported on micron scale structures, which are in turn supported on millimeter scale structures. This leads to a durable hierarchical structure to optimize the filtration efficiency with a minimum amount of material. Buckling coils,ootnotetextTao Han, Darrell H Reneker, Alexander L. Yarin, Polymer, Volume 48, issue 20 (September 21, 2007), p. 6064-6076. electrical bending coilsootnotetextDarrell H. Reneker and Alexander L. Yarin, Polymer, Volume 49, Issue 10 (2008) Pages 2387-2425, DOI:10.1016/j.polymer.2008.02.002. Feature Article. and pendulum coilsootnotetextT. Han, D.H. Reneker, A.L. Yarin, Polymer, Volume 49, (2008) Pages 2160-2169, doi:10.1016/jpolymer.2008.01.0487878. spanning dimensions from a few microns to a few centimeters can be collected from a single jet by controlling the position and motion of a collector. Attractive routes to the design and construction of hierarchical structures for filtration are based on nanofibers supported on small coils that are in turn supported on larger coils, which are supported on even larger overlapping coils. ``Such top-down'' hierarchical structures are easy to make by electrospinning. In one example, a thin hierarchical structure was made, with a high surface area and small interstices, having an open area of over 50%, with the thinnest fibers supported at least every 15 microns.

  20. Modular, Hierarchical Learning By Artificial Neural Networks

    NASA Technical Reports Server (NTRS)

    Baldi, Pierre F.; Toomarian, Nikzad

    1996-01-01

    Modular and hierarchical approach to supervised learning by artificial neural networks leads to neural networks more structured than neural networks in which all neurons fully interconnected. These networks utilize general feedforward flow of information and sparse recurrent connections to achieve dynamical effects. The modular organization, sparsity of modular units and connections, and fact that learning is much more circumscribed are all attractive features for designing neural-network hardware. Learning streamlined by imitating some aspects of biological neural networks.

  1. Learning by imitation: a hierarchical approach.

    PubMed

    Byrne, R W; Russon, A E

    1998-10-01

    To explain social learning without invoking the cognitively complex concept of imitation, many learning mechanisms have been proposed. Borrowing an idea used routinely in cognitive psychology, we argue that most of these alternatives can be subsumed under a single process, priming, in which input increases the activation of stored internal representations. Imitation itself has generally been seen as a "special faculty." This has diverted much research towards the all-or-none question of whether an animal can imitate, with disappointingly inconclusive results. In the great apes, however, voluntary, learned behaviour is organized hierarchically. This means that imitation can occur at various levels, of which we single out two clearly distinct ones: the "action level," a rather detailed and linear specification of sequential acts, and the "program level," a broader description of subroutine structure and the hierarchical layout of a behavioural "program." Program level imitation is a high-level, constructive mechanism, adapted for the efficient learning of complex skills and thus not evident in the simple manipulations used to test for imitation in the laboratory. As examples, we describe the food-preparation techniques of wild mountain gorillas and the imitative behaviour of orangutans undergoing "rehabilitation" to the wild. Representing and manipulating relations between objects seems to be one basic building block in their hierarchical programs. There is evidence that great apes suffer from a stricter capacity limit than humans in the hierarchical depth of planning. We re-interpret some chimpanzee behaviour previously described as "emulation" and suggest that all great apes may be able to imitate at the program level. Action level imitation is seldom observed in great ape skill learning, and may have a largely social role, even in humans. PMID:10097023

  2. Asymptotic analysis of hierarchical martensitic microstructure

    NASA Astrophysics Data System (ADS)

    Cesana, Pierluigi; Porta, Marcel; Lookman, Turab

    2014-12-01

    We consider a hierarchical nested microstructure, which also contains a point of singularity (disclination) at the origin, observed in lead orthovanadate. We show how to exactly compute the energy cost and associated displacement field within linearized elasticity by enforcing geometric compatibility of strains across interfaces of the three-phase mixture of distortions (variants) in the microstructure. We prove that the mechanical deformation is purely elastic and discuss the behavior of the system close to the origin.

  3. Ecobionanocomposites: Hierarchical supramolecular materials incorporating stereocomplexation

    NASA Astrophysics Data System (ADS)

    Dorgan, John

    2015-03-01

    Polylactides (PLAs) are a leading class of renewable plastics with several favorable sustainability metrics. However, for many applications basic PLA has insufficient properties. The combination of nanoscopic filler particles can be combined with the phenomena of stereocomplexation to create a new class of hierarchically structured materials. Recent progress on the development of these novel ecobionanocomposites is discussed. The following grants are deeply appreciated: USDA 2012-33610-19945 and NSF CMMI 1335338.

  4. TRANSIMS and the hierarchical data format

    SciTech Connect

    Bush, B.W.

    1997-06-12

    The Hierarchical Data Format (HDF) is a general-purposed scientific data format developed at the National Center for Supercomputing Applications. It supports metadata, compression, and a variety of data structures (multidimensional arrays, raster images, tables). FORTRAN 77 and ANSI C programming interfaces are available for it and a wide variety of visualization tools read HDF files. The author discusses the features of this file format and its possible uses in TRANSIMS.

  5. Hierarchical optimization for neutron scattering problems

    NASA Astrophysics Data System (ADS)

    Bao, Feng; Archibald, Rick; Bansal, Dipanshu; Delaire, Olivier

    2016-06-01

    We present a scalable optimization method for neutron scattering problems that determines confidence regions of simulation parameters in lattice dynamics models used to fit neutron scattering data for crystalline solids. The method uses physics-based hierarchical dimension reduction in both the computational simulation domain and the parameter space. We demonstrate for silicon that after a few iterations the method converges to parameters values (interatomic force-constants) computed with density functional theory simulations.

  6. Metal hierarchical patterning by direct nanoimprint lithography

    PubMed Central

    Radha, Boya; Lim, Su Hui; Saifullah, Mohammad S. M.; Kulkarni, Giridhar U.

    2013-01-01

    Three-dimensional hierarchical patterning of metals is of paramount importance in diverse fields involving photonics, controlling surface wettability and wearable electronics. Conventionally, this type of structuring is tedious and usually involves layer-by-layer lithographic patterning. Here, we describe a simple process of direct nanoimprint lithography using palladium benzylthiolate, a versatile metal-organic ink, which not only leads to the formation of hierarchical patterns but also is amenable to layer-by-layer stacking of the metal over large areas. The key to achieving such multi-faceted patterning is hysteretic melting of ink, enabling its shaping. It undergoes transformation to metallic palladium under gentle thermal conditions without affecting the integrity of the hierarchical patterns on micro- as well as nanoscale. A metallic rice leaf structure showing anisotropic wetting behavior and woodpile-like structures were thus fabricated. Furthermore, this method is extendable for transferring imprinted structures to a flexible substrate to make them robust enough to sustain numerous bending cycles. PMID:23446801

  7. Hierarchical structure of Turkey's foreign trade

    NASA Astrophysics Data System (ADS)

    Kantar, Ersin; Deviren, Bayram; Keskin, Mustafa

    2011-10-01

    We examine the hierarchical structures of Turkey's foreign trade by using real prices of their commodity export and import move together over time. We obtain the topological properties among the countries based on Turkey's foreign trade during the 1996-2010 period by using the concept of hierarchical structure methods (minimal spanning tree, (MST) and hierarchical tree, (HT)). These periods are divided into two subperiods, such as 1996-2002 and 2003-2010, in order to test various time-window and observe the temporal evolution. We perform the bootstrap techniques to investigate a value of the statistical reliability to the links of the MSTs and HTs. We also use a clustering linkage procedure in order to observe the cluster structure much better. From the structural topologies of these trees, we identify different clusters of countries according to their geographical location and economic ties. Our results show that the DE (Germany), UK (United Kingdom), FR (France), IT (Italy) and RU (Russia) are more important within the network, due to a tighter connection with other countries. We have also found that these countries play a significant role for Turkey's foreign trade and have important implications for the design of portfolio and investment strategies.

  8. Resilient 3D hierarchical architected metamaterials.

    PubMed

    Meza, Lucas R; Zelhofer, Alex J; Clarke, Nigel; Mateos, Arturo J; Kochmann, Dennis M; Greer, Julia R

    2015-09-15

    Hierarchically designed structures with architectural features that span across multiple length scales are found in numerous hard biomaterials, like bone, wood, and glass sponge skeletons, as well as manmade structures, like the Eiffel Tower. It has been hypothesized that their mechanical robustness and damage tolerance stem from sophisticated ordering within the constituents, but the specific role of hierarchy remains to be fully described and understood. We apply the principles of hierarchical design to create structural metamaterials from three material systems: (i) polymer, (ii) hollow ceramic, and (iii) ceramic-polymer composites that are patterned into self-similar unit cells in a fractal-like geometry. In situ nanomechanical experiments revealed (i) a nearly theoretical scaling of structural strength and stiffness with relative density, which outperforms existing nonhierarchical nanolattices; (ii) recoverability, with hollow alumina samples recovering up to 98% of their original height after compression to ≥ 50% strain; (iii) suppression of brittle failure and structural instabilities in hollow ceramic hierarchical nanolattices; and (iv) a range of deformation mechanisms that can be tuned by changing the slenderness ratios of the beams. Additional levels of hierarchy beyond a second order did not increase the strength or stiffness, which suggests the existence of an optimal degree of hierarchy to amplify resilience. We developed a computational model that captures local stress distributions within the nanolattices under compression and explains some of the underlying deformation mechanisms as well as validates the measured effective stiffness to be interpreted as a metamaterial property. PMID:26330605

  9. The traveling salesman problem: a hierarchical model.

    PubMed

    Graham, S M; Joshi, A; Pizlo, Z

    2000-10-01

    Our review of prior literature on spatial information processing in perception, attention, and memory indicates that these cognitive functions involve similar mechanisms based on a hierarchical architecture. The present study extends the application of hierarchical models to the area of problem solving. First, we report results of an experiment in which human subjects were tested on a Euclidean traveling salesman problem (TSP) with 6 to 30 cities. The subject's solutions were either optimal or near-optimal in length and were produced in a time that was, on average, a linear function of the number of cities. Next, the performance of the subjects is compared with that of five representative artificial intelligence and operations research algorithms, that produce approximate solutions for Euclidean problems. None of these algorithms was found to be an adequate psychological model. Finally, we present a new algorithm for solving the TSP, which is based on a hierarchical pyramid architecture. The performance of this new algorithm is quite similar to the performance of the subjects. PMID:11126941

  10. Hierarchical image classification in the bioscience literature.

    PubMed

    Kim, Daehyun; Yu, Hong

    2009-01-01

    Our previous work has shown that images appearing in bioscience articles can be classified into five types: Gel-Image, Image-of-Thing, Graph, Model, and Mix. For this paper, we explored and analyzed features strongly associated with each image type and developed a hierarchical image classification approach for classifying an image into one of the five types. First, we applied texture features to separate images into two groups: 1) a texture group comprising Gel Image, Image-of-Thing, and Mix, and 2) a non-texture group comprising Graph and Model. We then applied entropy, skewness, and uniformity for the first group, and edge difference, uniformity, and smoothness for the second group to classify images into specific types. Our results show that hierarchical image classification accurately divided images into the two groups during the initial classification and that the overall accuracy of the image classification was higher than that of our previous approach. In particular, the recall of hierarchical image classification was greatly improved due to the high accuracy of the initial classification. PMID:20351874

  11. Hierarchically Structured Materials for Lithium Batteries

    SciTech Connect

    Xiao, Jie; Zheng, Jianming; Li, Xiaolin; Shao, Yuyan; Zhang, Jiguang

    2013-09-25

    Lithium-ion battery (LIB) is one of the most promising power sources to be deployed in electric vehicles (EV), including solely battery powered vehicles, plug-in hybrid electric vehicles, and hybrid electrical vehicles. With the increasing demand on devices of high energy densities (>500 Wh/kg) , new energy storage systems, such as lithium-oxygen (Li-O2) batteries and other emerging systems beyond the conventional LIB also attracted worldwide interest for both transportation and grid energy storage applications in recent years. It is well known that the electrochemical performances of these energy storage systems depend not only on the composition of the materials, but also on the structure of electrode materials used in the batteries. Although the desired performances characteristics of batteries often have conflict requirements on the micro/nano-structure of electrodes, hierarchically designed electrodes can be tailored to satisfy these conflict requirements. This work will review hierarchically structured materials that have been successfully used in LIB and Li-O2 batteries. Our goal is to elucidate 1) how to realize the full potential of energy materials through the manipulation of morphologies, and 2) how the hierarchical structure benefits the charge transport, promotes the interfacial properties, prolongs the electrode stability and battery lifetime.

  12. Hierarchically structured materials for lithium batteries

    NASA Astrophysics Data System (ADS)

    Xiao, Jie; Zheng, Jianming; Li, Xiaolin; Shao, Yuyan; Zhang, Ji-Guang

    2013-10-01

    The lithium-ion battery (LIB) is one of the most promising power sources to be deployed in electric vehicles, including solely battery powered vehicles, plug-in hybrid electric vehicles, and hybrid electric vehicles. With the increasing demand for devices of high-energy densities (>500 Wh kg-1), new energy storage systems, such as lithium-oxygen (Li-O2) batteries and other emerging systems beyond the conventional LIB, have attracted worldwide interest for both transportation and grid energy storage applications in recent years. It is well known that the electrochemical performance of these energy storage systems depends not only on the composition of the materials, but also on the structure of the electrode materials used in the batteries. Although the desired performance characteristics of batteries often have conflicting requirements with the micro/nano-structure of electrodes, hierarchically designed electrodes can be tailored to satisfy these conflicting requirements. This work will review hierarchically structured materials that have been successfully used in LIB and Li-O2 batteries. Our goal is to elucidate (1) how to realize the full potential of energy materials through the manipulation of morphologies, and (2) how the hierarchical structure benefits the charge transport, promotes the interfacial properties and prolongs the electrode stability and battery lifetime.

  13. Hierarchically structured materials for lithium batteries.

    PubMed

    Xiao, Jie; Zheng, Jianming; Li, Xiaolin; Shao, Yuyan; Zhang, Ji-Guang

    2013-10-25

    The lithium-ion battery (LIB) is one of the most promising power sources to be deployed in electric vehicles, including solely battery powered vehicles, plug-in hybrid electric vehicles, and hybrid electric vehicles. With the increasing demand for devices of high-energy densities (>500 Wh kg(-1)), new energy storage systems, such as lithium-oxygen (Li-O2) batteries and other emerging systems beyond the conventional LIB, have attracted worldwide interest for both transportation and grid energy storage applications in recent years. It is well known that the electrochemical performance of these energy storage systems depends not only on the composition of the materials, but also on the structure of the electrode materials used in the batteries. Although the desired performance characteristics of batteries often have conflicting requirements with the micro/nano-structure of electrodes, hierarchically designed electrodes can be tailored to satisfy these conflicting requirements. This work will review hierarchically structured materials that have been successfully used in LIB and Li-O2 batteries. Our goal is to elucidate (1) how to realize the full potential of energy materials through the manipulation of morphologies, and (2) how the hierarchical structure benefits the charge transport, promotes the interfacial properties and prolongs the electrode stability and battery lifetime. PMID:24067410

  14. The generality of negative hierarchically restrictive behaviours.

    PubMed

    Brown, Jennie; Trafimow, David; Gregory, W Larry

    2005-03-01

    Previous research has shown that when an actor engages in a negative hierarchically restrictive behaviour, a strong correspondent trait attribution is made and this behaviour is expected to generalize across situations (Trafimow, 2001). This paper discusses three experiments that examined the effects of extreme situations and perceived morality of the actor on the way in which participants make trait attributions, and the extent to which those behaviours are expected to generalize to other situations. Findings from Experiments 1 and 2 indicate that even negative hierarchically restrictive behaviours do not always lead to strong correspondent inferences if the situation in which the initial behaviour was performed was sufficiently extreme. Experiment 3 served to support these findings and cleared up questions from the first two experiments. Findings supported the hypothesis that some situations inhibit negative trait attributions and behaviour generalizations. Furthermore, findings indicate that the perception of the morality of the actor determines whether or not a negative hierarchically restrictive behaviour will lead to a negative trait attribution and generalization. PMID:15901388

  15. [Comparative hierarchic structure of the genetic language].

    PubMed

    Ratner, V A

    1993-05-01

    The genetical texts and genetic language are built according to hierarchic principle and contain no less than 6 levels of coding sequences, separated by marks of punctuation, separation and indication: codons, cistrons, scriptons, replicons, linkage groups, genomes. Each level has all the attributes of the language. This hierarchic system expresses some general properties and regularities. The rules of genetic language being determined, the variability of genetical texts is generated by block-modular combinatorics on each level. Between levels there are some intermediate sublevels and module types capable of being combined. The genetic language is compared with two different independent linguistic systems: human natural languages and artificial programming languages. Genetic language is a natural one by its origin, but it is a typical technical language of the functioning genetic regulatory system--by its predestination. All three linguistic systems under comparison have evident similarity of the organization principles and hierarchical structures. This argues for similarity of their principles of appearance and evolution. PMID:8335232

  16. Hierarchical Bayesian model updating for structural identification

    NASA Astrophysics Data System (ADS)

    Behmanesh, Iman; Moaveni, Babak; Lombaert, Geert; Papadimitriou, Costas

    2015-12-01

    A new probabilistic finite element (FE) model updating technique based on Hierarchical Bayesian modeling is proposed for identification of civil structural systems under changing ambient/environmental conditions. The performance of the proposed technique is investigated for (1) uncertainty quantification of model updating parameters, and (2) probabilistic damage identification of the structural systems. Accurate estimation of the uncertainty in modeling parameters such as mass or stiffness is a challenging task. Several Bayesian model updating frameworks have been proposed in the literature that can successfully provide the "parameter estimation uncertainty" of model parameters with the assumption that there is no underlying inherent variability in the updating parameters. However, this assumption may not be valid for civil structures where structural mass and stiffness have inherent variability due to different sources of uncertainty such as changing ambient temperature, temperature gradient, wind speed, and traffic loads. Hierarchical Bayesian model updating is capable of predicting the overall uncertainty/variability of updating parameters by assuming time-variability of the underlying linear system. A general solution based on Gibbs Sampler is proposed to estimate the joint probability distributions of the updating parameters. The performance of the proposed Hierarchical approach is evaluated numerically for uncertainty quantification and damage identification of a 3-story shear building model. Effects of modeling errors and incomplete modal data are considered in the numerical study.

  17. Hierarchical models of animal abundance and occurrence

    USGS Publications Warehouse

    Royle, J. Andrew; Dorazio, R.M.

    2006-01-01

    Much of animal ecology is devoted to studies of abundance and occurrence of species, based on surveys of spatially referenced sample units. These surveys frequently yield sparse counts that are contaminated by imperfect detection, making direct inference about abundance or occurrence based on observational data infeasible. This article describes a flexible hierarchical modeling framework for estimation and inference about animal abundance and occurrence from survey data that are subject to imperfect detection. Within this framework, we specify models of abundance and detectability of animals at the level of the local populations defined by the sample units. Information at the level of the local population is aggregated by specifying models that describe variation in abundance and detection among sites. We describe likelihood-based and Bayesian methods for estimation and inference under the resulting hierarchical model. We provide two examples of the application of hierarchical models to animal survey data, the first based on removal counts of stream fish and the second based on avian quadrat counts. For both examples, we provide a Bayesian analysis of the models using the software WinBUGS.

  18. Resilient 3D hierarchical architected metamaterials

    PubMed Central

    Meza, Lucas R.; Zelhofer, Alex J.; Clarke, Nigel; Mateos, Arturo J.; Kochmann, Dennis M.; Greer, Julia R.

    2015-01-01

    Hierarchically designed structures with architectural features that span across multiple length scales are found in numerous hard biomaterials, like bone, wood, and glass sponge skeletons, as well as manmade structures, like the Eiffel Tower. It has been hypothesized that their mechanical robustness and damage tolerance stem from sophisticated ordering within the constituents, but the specific role of hierarchy remains to be fully described and understood. We apply the principles of hierarchical design to create structural metamaterials from three material systems: (i) polymer, (ii) hollow ceramic, and (iii) ceramic–polymer composites that are patterned into self-similar unit cells in a fractal-like geometry. In situ nanomechanical experiments revealed (i) a nearly theoretical scaling of structural strength and stiffness with relative density, which outperforms existing nonhierarchical nanolattices; (ii) recoverability, with hollow alumina samples recovering up to 98% of their original height after compression to ≥50% strain; (iii) suppression of brittle failure and structural instabilities in hollow ceramic hierarchical nanolattices; and (iv) a range of deformation mechanisms that can be tuned by changing the slenderness ratios of the beams. Additional levels of hierarchy beyond a second order did not increase the strength or stiffness, which suggests the existence of an optimal degree of hierarchy to amplify resilience. We developed a computational model that captures local stress distributions within the nanolattices under compression and explains some of the underlying deformation mechanisms as well as validates the measured effective stiffness to be interpreted as a metamaterial property. PMID:26330605

  19. Hierarchical microimaging of bone structure and function.

    PubMed

    Müller, Ralph

    2009-07-01

    With recent advances in molecular medicine and disease treatment in osteoporosis, quantitative image processing of three-dimensional bone structures is critical in the context of bone quality assessment. Biomedical imaging technology such as MRI or CT is readily available, but few attempts have been made to expand the capabilities of these systems by integrating quantitative analysis tools and by exploring structure-function relationships in a hierarchical fashion. Nevertheless, such quantitative end points are an important factor for success in basic research and in the development of novel therapeutic strategies. CT is key to these developments, as it images and quantifies bone in three dimensions and provides multiscale biological imaging capabilities with isotropic resolutions of a few millimeters (clinical CT), a few tens of micrometers (microCT) and even as high as 100 nanometers (nanoCT). The technology enables the assessment of the relationship between microstructural and ultrastructural measures of bone quality and certain diseases or therapies. This Review focuses on presenting strategies for three-dimensional approaches to hierarchical biomechanical imaging in the study of microstructural and ultrastructural bone failure. From this Review, it can be concluded that biomechanical imaging is extremely valuable for the study of bone failure mechanisms at different hierarchical levels. PMID:19568252

  20. System and method for time synchronization in a wireless network

    DOEpatents

    Gonia, Patrick S.; Kolavennu, Soumitri N.; Mahasenan, Arun V.; Budampati, Ramakrishna S.

    2010-03-30

    A system includes multiple wireless nodes forming a cluster in a wireless network, where each wireless node is configured to communicate and exchange data wirelessly based on a clock. One of the wireless nodes is configured to operate as a cluster master. Each of the other wireless nodes is configured to (i) receive time synchronization information from a parent node, (ii) adjust its clock based on the received time synchronization information, and (iii) broadcast time synchronization information based on the time synchronization information received by that wireless node. The time synchronization information received by each of the other wireless nodes is based on time synchronization information provided by the cluster master so that the other wireless nodes substantially synchronize their clocks with the clock of the cluster master.

  1. Comparison of different undulator schemes with superimposed alternating gradients for the VUV-FEL at the TESLA Test Facility

    SciTech Connect

    Pflueger, J.; Nikitina, Y.M.

    1995-12-31

    For the VUV-FEL at the TESLA Test Facility an undulator with a total length of 30 m is needed. In this study three different approaches to realize an undulator with a sinusoidal plus a superimposed quadrupolar field were studied with the 3D code MAFIA.

  2. Design considerations and analysis of potential applications of a high power ultraviolet FEL at the TESLA test facility at DESY

    NASA Astrophysics Data System (ADS)

    Pagani, C.; Saldin, E. L.; Schneidmiller, E. A.; Yurkov, M. V.

    1999-02-01

    A possibility of constructing a high power ultraviolet free electron laser at the TESLA test facility at DESY is discussed. The proposed facility consists of a tunable master oscillator (P av˜10 mW, P peak˜10 kW, λ≃200-350 nm) and an FEL amplifier with a tapered undulator. The average and peak radiation power at the exit of the FEL amplifier is about 7 kW and 220 GW, respectively. Installation of such a facility can significantly extend scientific potential of the TESLA test facility. The UV free electron laser can be used to construct a polarized, monochromatic gamma-source with the ultimate yield up to 10 12 gamma-quanta per second and the maximal energy of about 100 MeV. An intensive gamma-source can also form the base for constructing the test facility for the TESLA positron generation system. Another accelerator application of the proposed facility is verification of the main technical solutions for the laser and the optical system to be used in the gamma-gamma option of the TESLA collider. A high average power UV laser is also promising for industrial applications.

  3. Does Magnetic Resonance Brain Scanning at 3.0 Tesla Pose a Hyperthermic Challenge to Term Neonates?

    PubMed

    Cawley, Paul; Few, Karen; Greenwood, Richard; Malcolm, Paul; Johnson, Glyn; Lally, Pete; Thayyil, Sudhin; Clarke, Paul

    2016-08-01

    Next-generation 3-Tesla magnetic resonance (MR) scanners offer improved neonatal neuroimaging, but the greater associated radiofrequency radiation may increase the risk of hyperthermia. Safety data for neonatal 3-T MR scanning are lacking. We measured rectal temperatures continuously in 25 neonates undergoing 3-T brain MR imaging and observed no significant hyperthermic threat. PMID:27318382

  4. Toward cardiac electrophysiological mapping based on micro-Tesla NMR: a novel modality for localizing the cardiac reentry

    NASA Astrophysics Data System (ADS)

    Kim, Kiwoong

    2012-06-01

    Matching the proton magnetic resonance frequency to the frequency of a periodic electrophysiological excitation of myocardium enables direct localization of the cardiac reentry by magnetic resonance imaging techniques. The feasibility of this new idea has been demonstrated by conducting a numerical simulation based on a realistic heart model and experimental parameters in SQUID-based micro-Tesla NMR.

  5. Wireless Sensing Opportunities for Aerospace Applications

    NASA Technical Reports Server (NTRS)

    Wilson, William; Atkinson, Gary

    2007-01-01

    Wireless sensors and sensor networks is an emerging technology area with many applications within the aerospace industry. Integrated vehicle health monitoring (IVHM) of aerospace vehicles is needed to ensure the safety of the crew and the vehicle, yet often high costs, weight, size and other constraints prevent the incorporation of instrumentation onto spacecraft. This paper presents a few of the areas such as IVHM, where new wireless sensing technology is needed on both existing vehicles as well as future spacecraft. From ground tests to inflatable structures to the International Space Station, many applications could receive benefits from small, low power, wireless sensors. This paper also highlights some of the challenges that need to overcome when implementing wireless sensor networks for aerospace vehicles.

  6. Terahertz wireless communications based on photonics technologies.

    PubMed

    Nagatsuma, Tadao; Horiguchi, Shogo; Minamikata, Yusuke; Yoshimizu, Yasuyuki; Hisatake, Shintaro; Kuwano, Shigeru; Yoshimoto, Naoto; Terada, Jun; Takahashi, Hiroyuki

    2013-10-01

    There has been an increasing interest in the application of terahertz (THz) waves to broadband wireless communications. In particular, use of frequencies above 275 GHz is one of the strong concerns among radio scientists and engineers, because these frequency bands have not yet been allocated at specific active services, and there is a possibility to employ extremely large bandwidths for ultra-broadband wireless communications. Introduction of photonics technologies for signal generation, modulation and detection is effective not only to enhance the bandwidth and/or the data rate, but also to combine fiber-optic (wired) and wireless networks. This paper reviews recent progress in THz wireless communications using telecom-based photonics technologies towards 100 Gbit/s. PMID:24104286

  7. On computer vision in wireless sensor networks.

    SciTech Connect

    Berry, Nina M.; Ko, Teresa H.

    2004-09-01

    Wireless sensor networks allow detailed sensing of otherwise unknown and inaccessible environments. While it would be beneficial to include cameras in a wireless sensor network because images are so rich in information, the power cost of transmitting an image across the wireless network can dramatically shorten the lifespan of the sensor nodes. This paper describe a new paradigm for the incorporation of imaging into wireless networks. Rather than focusing on transmitting images across the network, we show how an image can be processed locally for key features using simple detectors. Contrasted with traditional event detection systems that trigger an image capture, this enables a new class of sensors which uses a low power imaging sensor to detect a variety of visual cues. Sharing these features among relevant nodes cues specific actions to better provide information about the environment. We report on various existing techniques developed for traditional computer vision research which can aid in this work.

  8. Epidemic Propagation In Overlaid Wireless Networks

    SciTech Connect

    Yanmaz, Evsen

    2008-01-01

    Witb tbe emergence of computer worms tbat can spread over air interfaces, wireless ad boc and sensor networks can be vulnerable to node compromises even if the deployed network is not connected to the backbone. Depending on the physical topology of the wireless network, even a single infected node can compromise the whole network. In this work, epidemic (e.g., worm) propagation in a static wireless network is studied, where a number of inCected mobile nodes are injected over the existing network. It is shown that the epidemic spread threshold and size depend on the physical topology of the underlying static wireless network as well as the mobility model employed by the infected mobile nodes. More specifically, results show that in a Cully-connected static wirelessnctwork targeted attacks are more effective, wbereas Cor a random topology random attacks can be sufficient to compromise the whole network.

  9. Feasibility study of wireless power transmission systems

    NASA Technical Reports Server (NTRS)

    Robinson, W. J., Jr.

    1968-01-01

    Wireless microwave or laser energy transfers power from a manned earth-orbiting central station to unmanned astronomical substations. More efficient systems are required for the microwave power transmission.

  10. Wireless technology in disease management and medicine.

    PubMed

    Clifford, Gari D; Clifton, David

    2012-01-01

    Healthcare information, and to some extent patient management, is progressing toward a wireless digital future. This change is driven partly by a desire to improve the current state of medicine using new technologies, partly by supply-and-demand economics, and partly by the utility of wireless devices. Wired technology can be cumbersome for patient monitoring and can restrict the behavior of the monitored patients, introducing bias or artifacts. However, wireless technologies, while mitigating some of these issues, have introduced new problems such as data dropout and "information overload" for the clinical team. This review provides an overview of current wireless technology used for patient monitoring and disease management. We identify some of the major related issues and describe some existing and possible solutions. In particular, we discuss the rapidly evolving fields of telemedicine and mHealth in the context of increasingly resource-constrained healthcare systems. PMID:22053737

  11. Securing radars using secure wireless sensor networking

    NASA Astrophysics Data System (ADS)

    Tahmoush, David

    2014-06-01

    Radar sensors can be viewed as a limited wireless sensor network consisting of radar transmitter nodes, target nodes, and radar receiver nodes. The radar transmitter node sends a communication signal to the target node which then reflects it in a known pattern to the radar receiver nodes. This type of wireless sensor network is susceptible to the same types of attacks as a traditional wireless sensor network, but there is less opportunity for defense. The target nodes in the network are unable to validate the return signal, and they are often uncooperative. This leads to ample opportunities for spoofing and man-in-the-middle attacks. This paper explores some of the fundamental techniques that can be used against a limited wireless network system as well as explores the techniques that can be used to counter them.

  12. Wireless Networking for Control: Technologies and Models

    NASA Astrophysics Data System (ADS)

    Johansson, Mikael; Jäntti, Riku

    This chapter discusses technologies and models for low power wireless industrial communication. The aim of the text is to narrow the gap between the models used in the theoretical control literature with models that arise when tools from communication theory are used to model emerging standards for industrial wireless. The chapter provides a tutorial overview covering basic concepts and models for wireless propagation, medium access control, multi-hop networking, routing and transport protocols. Throughout, an effort is made to describe both key technologies and associated models of control-relevant characteristics such as latency and loss. Some existing and emerging specifications and standards, including Zigbee, WirelessHART and ISA100, are described in some detail, and links are made between the developed models and useful network abstractions for control design.

  13. MC-CDMA for optical wireless communications

    NASA Astrophysics Data System (ADS)

    Luan, Yingzi; Jiang, Guang; Li, Jiandong

    2005-11-01

    MC-CDMA is a spectrum-efficient modulation in RF systems. Here it is used in optical wireless communications. Performance is simulated by using multiuser detection. Spatial Diversity is also considered and analyzed.

  14. Wireless powering of e -swimmers

    PubMed Central

    Roche, Jérome; Carrara, Serena; Sanchez, Julien; Lannelongue, Jérémy; Loget, Gabriel; Bouffier, Laurent; Fischer, Peer; Kuhn, Alexander

    2014-01-01

    Miniaturized structures that can move in a controlled way in solution and integrate various functionalities are attracting considerable attention due to the potential applications in fields ranging from autonomous micromotors to roving sensors. Here we introduce a concept which allows, depending on their specific design, the controlled directional motion of objects in water, combined with electronic functionalities such as the emission of light, sensing, signal conversion, treatment and transmission. The approach is based on electric field-induced polarization, which triggers different chemical reactions at the surface of the object and thereby its propulsion. This results in a localized electric current that can power in a wireless way electronic devices in water, leading to a new class of electronic swimmers (e-swimmers). PMID:25330809

  15. Reliability of wireless sensor networks.

    PubMed

    Dâmaso, Antônio; Rosa, Nelson; Maciel, Paulo

    2014-01-01

    Wireless Sensor Networks (WSNs) consist of hundreds or thousands of sensor nodes with limited processing, storage, and battery capabilities. There are several strategies to reduce the power consumption of WSN nodes (by increasing the network lifetime) and increase the reliability of the network (by improving the WSN Quality of Service). However, there is an inherent conflict between power consumption and reliability: an increase in reliability usually leads to an increase in power consumption. For example, routing algorithms can send the same packet though different paths (multipath strategy), which it is important for reliability, but they significantly increase the WSN power consumption. In this context, this paper proposes a model for evaluating the reliability of WSNs considering the battery level as a key factor. Moreover, this model is based on routing algorithms used by WSNs. In order to evaluate the proposed models, three scenarios were considered to show the impact of the power consumption on the reliability of WSNs. PMID:25157553

  16. Low Frequency Wireless Communications Technology

    SciTech Connect

    Bartone, Erik J; Carbone, John F

    2004-01-27

    The purpose of this project was to demonstrate Nxegen's real-time wireless electricity monitoring and load management technologies in selected commercial, industrial, and municipal end user facilities. The purpose of which is to demonstrate the ability for Nxegen's technology to collect real-time electricity data to a central location (Nxegen's Network Operation Center "NOC"), aggregate customer load profiles into portfolios of profiles, and be able to dispatch load curtailment commands from the NOC to individual customer loads to demonstrate the ability to integrate demand resources into the overall electric utility system for the purpose of; (1) improving overall system reliability, (2) reducing wholesale electric generation prices (locational marginal prices "LMP"), and (3) reducing congestion costs in energy constrained areas (southwest Connecticut).

  17. Wireless Orbiter Hang-Angle Inclinometer System

    NASA Technical Reports Server (NTRS)

    Lucena, Angel; Perotti, Jose; Green, Eric; Byon, Jonathan; Burns, Bradley; Mata, Carlos; Randazzo, John; Blalock, Norman

    2011-01-01

    A document describes a system to reliably gather the hang-angle inclination of the orbiter. The system comprises a wireless handheld master station (which contains the main station software) and a wireless remote station (which contains the inclinometer sensors, the RF transceivers, and the remote station software). The remote station is designed to provide redundancy to the system. It includes two RF transceivers, two power-management boards, and four inclinometer sensors.

  18. Routing Security in Ad Hoc Wireless Networks

    NASA Astrophysics Data System (ADS)

    Pervaiz, Mohammad O.; Cardei, Mihaela; Wu, Jie

    Wireless networks provide rapid, untethered access to information and computing, eliminating the barriers of distance, time, and location for many applications ranging from collaborative, distributed mobile computing to disaster recovery (such as fire, flood, earthquake), law enforcement (crowd control, search, and rescue), and military communications (command, control, surveillance, and reconnaissance). An ad hoc network is a collection of wireless mobile hosts forming a temporary network without the aid of any established infrastructure or centralized administration [11

  19. Wireless Multiplexed Surface Acoustic Wave Sensors Project

    NASA Technical Reports Server (NTRS)

    Youngquist, Robert C.

    2014-01-01

    Wireless Surface Acoustic Wave (SAW) Sensor is a new technology for obtaining multiple, real-time measurements under extreme environmental conditions. This project plans to develop a wireless multiplexed sensor system that uses SAW sensors, with no batteries or semiconductors, that are passive and rugged, can operate down to cryogenic temperatures and up to hundreds of degrees C, and can be used to sense a wide variety of parameters over reasonable distances (meters).

  20. How to model wireless mesh networks topology

    NASA Astrophysics Data System (ADS)

    Sanni, M. L.; Hashim, A. A.; Anwar, F.; Ahmed, G. S. M.; Ali, S.

    2013-12-01

    The specification of network connectivity model or topology is the beginning of design and analysis in Computer Network researches. Wireless Mesh Networks is an autonomic network that is dynamically self-organised, self-configured while the mesh nodes establish automatic connectivity with the adjacent nodes in the relay network of wireless backbone routers. Researches in Wireless Mesh Networks range from node deployment to internetworking issues with sensor, Internet and cellular networks. These researches require modelling of relationships and interactions among nodes including technical characteristics of the links while satisfying the architectural requirements of the physical network. However, the existing topology generators model geographic topologies which constitute different architectures, thus may not be suitable in Wireless Mesh Networks scenarios. The existing methods of topology generation are explored, analysed and parameters for their characterisation are identified. Furthermore, an algorithm for the design of Wireless Mesh Networks topology based on square grid model is proposed in this paper. The performance of the topology generated is also evaluated. This research is particularly important in the generation of a close-to-real topology for ensuring relevance of design to the intended network and validity of results obtained in Wireless Mesh Networks researches.

  1. Analysis and Testing of Mobile Wireless Networks

    NASA Technical Reports Server (NTRS)

    Alena, Richard; Evenson, Darin; Rundquist, Victor; Clancy, Daniel (Technical Monitor)

    2002-01-01

    Wireless networks are being used to connect mobile computing elements in more applications as the technology matures. There are now many products (such as 802.11 and 802.11b) which ran in the ISM frequency band and comply with wireless network standards. They are being used increasingly to link mobile Intranet into Wired networks. Standard methods of analyzing and testing their performance and compatibility are needed to determine the limits of the technology. This paper presents analytical and experimental methods of determining network throughput, range and coverage, and interference sources. Both radio frequency (BE) domain and network domain analysis have been applied to determine wireless network throughput and range in the outdoor environment- Comparison of field test data taken under optimal conditions, with performance predicted from RF analysis, yielded quantitative results applicable to future designs. Layering multiple wireless network- sooners can increase performance. Wireless network components can be set to different radio frequency-hopping sequences or spreading functions, allowing more than one sooner to coexist. Therefore, we ran multiple 802.11-compliant systems concurrently in the same geographical area to determine interference effects and scalability, The results can be used to design of more robust networks which have multiple layers of wireless data communication paths and provide increased throughput overall.

  2. Airborne wireless communication systems, airborne communication methods, and communication methods

    DOEpatents

    Deaton, Juan D.; Schmitt, Michael J.; Jones, Warren F.

    2011-12-13

    An airborne wireless communication system includes circuitry configured to access information describing a configuration of a terrestrial wireless communication base station that has become disabled. The terrestrial base station is configured to implement wireless communication between wireless devices located within a geographical area and a network when the terrestrial base station is not disabled. The circuitry is further configured, based on the information, to configure the airborne station to have the configuration of the terrestrial base station. An airborne communication method includes answering a 911 call from a terrestrial cellular wireless phone using an airborne wireless communication system.

  3. Wireless Network Communications Overview for Space Mission Operations

    NASA Technical Reports Server (NTRS)

    Fink, Patrick W.

    2009-01-01

    The mission of the On-Board Wireless Working Group (WWG) is to serve as a general CCSDS focus group for intra-vehicle wireless technologies. The WWG investigates and makes recommendations pursuant to standardization of applicable wireless network protocols, ensuring the interoperability of independently developed wireless communication assets. This document presents technical background information concerning uses and applicability of wireless networking technologies for space missions. Agency-relevant driving scenarios, for which wireless network communications will provide a significant return-on-investment benefiting the participating international agencies, are used to focus the scope of the enclosed technical information.

  4. Impairment of chondrocyte biosynthetic activity by exposure to 3-tesla high-field magnetic resonance imaging is temporary.

    PubMed

    Sunk, Ilse-Gerlinde; Trattnig, Siegfried; Graninger, Winfried B; Amoyo, Love; Tuerk, Birgit; Steiner, Carl-Walter; Smolen, Josef S; Bobacz, Klaus

    2006-01-01

    The influence of magnetic resonance imaging (MRI) devices at high field strengths on living tissues is unknown. We investigated the effects of a 3-tesla electromagnetic field (EMF) on the biosynthetic activity of bovine articular cartilage. Bovine articular cartilage was obtained from juvenile and adult animals. Whole joints or cartilage explants were subjected to a pulsed 3-tesla EMF; controls were left unexposed. Synthesis of sulfated glycosaminoglycans (sGAGs) was measured by using [35S]sulfate incorporation; mRNA encoding the cartilage markers aggrecan and type II collagen, as well as IL-1beta, were analyzed by RT-PCR. Furthermore, effects of the 3-tesla EMF were determined over the course of time directly after exposure (day 0) and at days 3 and 6. In addition, the influence of a 1.5-tesla EMF on cartilage sGAG synthesis was evaluated. Chondrocyte cell death was assessed by staining with Annexin V and TdT-mediated dUTP nick end labelling (TUNEL). Exposure to the EMF resulted in a significant decrease in cartilage macromolecule synthesis. Gene expression of both aggrecan and IL-1beta, but not of collagen type II, was reduced in comparison with controls. Staining with Annexin V and TUNEL revealed no evidence of cell death. Interestingly, chondrocytes regained their biosynthetic activity within 3 days after exposure, as shown by proteoglycan synthesis rate and mRNA expression levels. Cartilage samples exposed to a 1.5-tesla EMF remained unaffected. Although MRI devices with a field strength of more than 1.5 T provide a better signal-to-noise ratio and thereby higher spatial resolution, their high field strength impairs the biosynthetic activity of articular chondrocytes in vitro. Although this decrease in biosynthetic activity seems to be transient, articular cartilage exposed to high-energy EMF may become vulnerable to damage. PMID:16831232

  5. D-zero rototrack: first stage of D-zero 2 Tesla solenoid field mapping device

    SciTech Connect

    Yamada, R.; Korienek, J.; Krider, J.; Lindenmeyer, C.; Miksa, D.; Miksa, R.

    1997-09-01

    A simple and portable field mapping device was developed at Fermilab and successfully used to test the D0 2 Tesla solenoid at Toshiba Works in Japan. A description of the mechanical structure, electric driving and control system, and software of the field mapping device is given. Four Hall probe elements of Group3 Digital Gaussmeters are mounted on the radial extension arm of a carriage, which is mounted on a central rotating beam. The system gives two dimensional motions (axial and rotational) to the Hall probes. To make the system compact and portable, we used a laptop computer with PCMCIA cards. For the control system we used commercially available software LabVIEW and Motion Toolbox, and for the data analysis we used Microsoft Excel.

  6. Mapping quantal touch using 7 Tesla functional magnetic resonance imaging and single-unit intraneural microstimulation.

    PubMed

    Sanchez Panchuelo, Rosa Maria; Ackerley, Rochelle; Glover, Paul M; Bowtell, Richard W; Wessberg, Johan; Francis, Susan T; McGlone, Francis

    2016-01-01

    Using ultra-high field 7 Tesla (7T) functional magnetic resonance imaging (fMRI), we map the cortical and perceptual responses elicited by intraneural microstimulation (INMS) of single mechanoreceptive afferent units in the median nerve, in humans. Activations are compared to those produced by applying vibrotactile stimulation to the unit's receptive field, and unit-type perceptual reports are analyzed. We show that INMS and vibrotactile stimulation engage overlapping areas within the topographically appropriate digit representation in the primary somatosensory cortex. Additional brain regions in bilateral secondary somatosensory cortex, premotor cortex, primary motor cortex, insula and posterior parietal cortex, as well as in contralateral prefrontal cortex are also shown to be activated in response to INMS. The combination of INMS and 7T fMRI opens up an unprecedented opportunity to bridge the gap between first-order mechanoreceptive afferent input codes and their spatial, dynamic and perceptual representations in human cortex. PMID:27154626

  7. Counteracting radio frequency inhomogeneity in the human brain at 7 Tesla using strongly modulating pulses.

    PubMed

    Boulant, N; Mangin, J-F; Amadon, A

    2009-05-01

    We report flip angle and spoiled gradient echo measurements at 7 Tesla on human brains in three-dimensional imaging, using strongly modulating pulses to counteract the transmitted radiofrequency inhomogeneity problem. Compared with the standard square pulse results, three points of improvement are demonstrated, namely: (i) the removal of the bright center (typical at high fields when using a quadrature head coil), (ii) the substantial gain of signal in the regions of low B(1) intensity, and (iii) an increased 35% signal uniformity over the whole brain at the flip angle where maximum contrast between white and gray matter occurs. We also find by means of simulations that standard BIR-4 adiabatic pulses need several times more energy to reach a similar performance at the same field strength. PMID:19253378

  8. [MR angiography of pelvic veins and the inferior vena cava using 0.5 tesla].

    PubMed

    Haubold-Reuter, B; Nicolas, V

    1994-10-01

    The pelvic veins and/or the inferior vena cava were examined in 15 patients with pelvic vein thrombosis or retroperitoneal tumours, using phlebography or cavography and MR angiography. The latter was carried out using 0.5 Tesla with an inflow technique TR/TE 30/8 ms, flip angle 70 degrees). 3-D projection angiograms were obtained from the 2-D angiograms in the coronary plane. Image quality was generally satisfactory and the veins up to the internal iliac could be demonstrated in all cases; below this, the examination was unreliable. Comparison of the methods with reference to information of therapeutic relevance has shown that in two-thirds of all examinations (8/13) MR angiography and phlebography were of equal diagnostic value. In the presence of a renal cell carcinoma, MR angiography was unable to distinguish between thrombosis and infiltration of the vena cava. PMID:7948977

  9. Light scattering from liquid crystal director fluctuations in steady magnetic fields up to 25 tesla

    NASA Astrophysics Data System (ADS)

    Challa, Pavan K.; Curtiss, O.; Williams, J. C.; Twieg, R.; Toth, J.; McGill, S.; Jákli, A.; Gleeson, J. T.; Sprunt, S. N.

    2012-07-01

    We report on homodyne dynamic light scattering measurements of orientational fluctuation modes in both calamitic and bent-core nematic liquid crystals, carried out in the new split-helix resistive magnet at the National High Magnetic Field Laboratory. The relaxation rate and inverse scattered intensity of director fluctuations exhibit a linear dependence on field-squared up to 25 tesla, which is consistent with strictly lowest order coupling of the tensor order parameter Q to field (QαβBαBβ) in the nematic free energy. However, we also observe evidence of field dependence of certain nematic material parameters, an effect which may be expected from the mean field scaling of these quantities with the magnitude of Q and the predicted variation of Q with field.

  10. Light scattering from liquid crystal director fluctuations in steady magnetic fields up to 25 tesla.

    PubMed

    Challa, Pavan K; Curtiss, O; Williams, J C; Twieg, R; Toth, J; McGill, S; Jákli, A; Gleeson, J T; Sprunt, S N

    2012-07-01

    We report on homodyne dynamic light scattering measurements of orientational fluctuation modes in both calamitic and bent-core nematic liquid crystals, carried out in the new split-helix resistive magnet at the National High Magnetic Field Laboratory. The relaxation rate and inverse scattered intensity of director fluctuations exhibit a linear dependence on field-squared up to 25 tesla, which is consistent with strictly lowest order coupling of the tensor order parameter Q to field (Q(αβ)B(α)B(β)) in the nematic free energy. However, we also observe evidence of field dependence of certain nematic material parameters, an effect which may be expected from the mean field scaling of these quantities with the magnitude of Q and the predicted variation of Q with field. PMID:23005438

  11. Undulator system for the VUV FEL at the TESLA test facility phase-2

    NASA Astrophysics Data System (ADS)

    Pflüger, J.; Hahn, U.; Faatz, B.; Tischer, M.

    2003-07-01

    The Phase-1 of the VUV Free Electron Laser at the TESLA Test Facility finishes in fall 2002. Phase-2, an extension of Phase-1 towards shorter wavelengths is under construction and will be ready for operation in 2003. A radiation wavelength as low as 6 nm will be obtained by raising the electron energy to 1 GeV. There will be only minor changes to the undulator system. Compared to Phase-1, six instead of three undulator segments will be installed. The integrated focusing system will be replaced by an electromagnetic doublet structure. We report about the changes of the undulator, the undulator vacuum system, the separated quadrupoles including a stretched wire alignment systems and the modifications to the beam diagnostic system consisting of pick up monitors and wire scanners.

  12. A VUV free electron laser at the TESLA test facility at DESY

    NASA Astrophysics Data System (ADS)

    Rossbach, J.; Tesla Fel Study Group

    1996-02-01

    We present the layout of a single pass free electron laser (FEL) to be driven by the TESLA Test Facility (TTF) currently under construction at DESY. The TTF is a test-bed for high-gradient, high efficiency superconducting acceleration sections for a future linear collider. Due to its unrivaled ability to sustain high beam quality during acceleration, a superconducting rf linac is considered the optimum choice to drive a FEL. We aim at a photon wavelength of λ = 6 nm utilizing the TTF after it has been extended to 1 GeV beam energy. Due to lack of mirrors and seed-lasers in this wavelength regime, a single pass FEL and self-amplified spontaneous emission (SASE) is considered. A first test is foreseen at a larger photon wavelength. The overall design as well as both electron and photon beam properties are discussed.

  13. Application of FPGA technology for control of superconducting TESLA cavities in free electron laser

    NASA Astrophysics Data System (ADS)

    Pozniak, Krzysztof T.

    2006-10-01

    Contemporary fundamental research in physics, biology, chemistry, pharmacology, material technology and other uses frequently methods basing on collision of high energy particles or penetration of matter with ultra-short electromagnetic waves. Kinetic energy of involved particles, considerably greater than GeV, is generated in accelerators of unique construction. The paper presents a digest of working principles of accelerators. There are characterized research methods which use accelerators. A method to stabilize the accelerating EM field in superconducting (SC) resonant cavity was presented. An example was given of usage of TESLA cavities in linear accelerator propelling the FLASH free electron laser (FEL) in DESY, Hamburg. Electronic and photonic control system was debated. The system bases on advanced FPGA circuits and cooperating fast DSP microprocessor chips. Examples of practical solutions were described. Test results of the debated systems in the real-time conditions were given.

  14. Beam Based HOM Analysis of Accelerating Structures at the TESLA Test Facility Linac

    SciTech Connect

    Wendt, M.; Schreiber, S.; Castro, P.; Gossel, A.; Huning, M.; Devanz, G.; Jablonka, M.; Magne, C.; Napoly, O.; Baboi, N.; /SLAC

    2005-08-09

    The beam emittance in future linear accelerators for high energy physics and SASE-FEL applications depends highly on the field performance in the accelerating structures, i.e. the damping of higher order modes (HOM). Besides theoretical and laboratory analysis, a beam based analysis technique was established [1] at the TESLA Test Facility (TTF) linac. It uses a charge modulated beam of variable modulation frequency to excite dipole modes. This causes a modulation of the transverse beam displacement, which is observed at a downstream BPM and associated with a direct analysis of the modes at the HOM-couplers. A brief introduction of eigenmodes of a resonator and the concept of the wake potential is given. Emphasis is put on beam instrumentation and signal analysis aspects, required for this beam based HOM measurement technique.

  15. Preattentive mechanisms of change detection in early auditory cortex: a 7 Tesla fMRI study.

    PubMed

    Szycik, G R; Stadler, J; Brechmann, A; Münte, T F

    2013-12-01

    The auditory system continuously monitors the environment for irregularities in an automatic, preattentive fashion. This is presumably accomplished by two mechanisms: a sensory mechanism detects a deviant sound on the basis of differential refractoriness of neural populations sensitive to the standard and deviant sounds, whereas the cognitive mechanism reveals deviance by comparing incoming auditory information with a template derived from previous input. Using fast event-related high-resolution functional magnetic resonance imaging at 7 Tesla we show that both mechanisms can be mapped to different parts of the auditory cortex both at the group level and the single-subject level. The sensory mechanism is supported by primary auditory areas in Heschl's gyrus whereas the cognitive mechanism is implemented in more anterior secondary auditory areas. Both mechanisms are equally engaged by simple sine-wave tones and speech-related phonemes indicating that streams of speech and non-speech stimuli are processed in a similar fashion. PMID:23994180

  16. Fabrication and characterization of a MEMS nano-Tesla ferromagnetic-piezoelectric magnetic sensor array

    NASA Astrophysics Data System (ADS)

    Qu, Peng; Gollapudi, Sreenivasulu; Bidthanapally, Rao; Srinivasan, Gopalan; Petrov, Vladimir; Qu, Hongwei

    2016-06-01

    A self-biased MEMS magnetic sensor array with ferromagnetic-piezoelectric composites has been fabricated and characterized. The array with two Quartz-Nickel-Metglas cantilevers with nano-tesla sensitivity was fabricated by MEMS processes including silicon-quartz low temperature bonding, quartz wafer thinning, and electroplating of thick nickel thin films. Under self-biasing due to magnetization grading of ferromagnetic layer, magnetoelectric coefficients of 6.6 and 5.6 V/cm Oe and resolutions of ˜0.58 and ˜0.75 nT are obtained at the mechanical resonant frequencies of 191.5 and 184.8 Hz for the two sensors in the array, respectively. Such arrays have the potential for applications in biomagnetic imaging technologies including magneto-cardiography.

  17. Steering and focusing effects in TESLA cavity due to high order mode and input couplers

    SciTech Connect

    Piot, P.; Dohlus, M.; Flottmann, K.; Marx, M.; Wipf, S.G.; /DESY

    2005-05-01

    Many state-of-art electron accelerator proposals incorporate TESLA-type superconducting radio-frequency (rf) cavities [1]. These standing wave rf cavities include rf input couplers and a pair of high order mode (HOM) couplers to absorb the energy associated to HOM field excited as the bunch passes through the cavity. In the present paper we investigate, using numerical simulations, the impact of the input and HOM couplers on the beam dynamics to zeroth and first order in initial position, and present parametric studies of the strength of these effects for various incoming beam energies. We finally study the impact of this asymmetric field on the beam dynamics, taking as an example the low energy section of the X-ray FEL injector.

  18. Current Progress in Fabrication of a 14 Tesla Nb3Sn Dipole

    NASA Astrophysics Data System (ADS)

    Holik, Eddie, III; Benson, Christopher; Damborsky, Kyle; Diaczenko, Nick; Elliott, Tim; Garrison, Ray; Jaisle, Andrew; McInturff, Alfred; McIntyre, Peter; Sattarov, Dior

    2012-03-01

    The Accelerator Technology Laboratory at Texas A&M is fabricating a model dipole magnet, TAMU3, designed to operate at a 14 Tesla bore field. The dipole employs an advanced internal-tin Nb3Sn/Cu composite strand with enhanced current density. The coils must be processed through a heat treatment after winding, during which the Sn within the heterogeneous strands diffuse into the Cu/Nb matrix to form high-performance superconducting layers. Heat treatment of the first coil assembly revealed tin leakage from the Sn cores that was caused by omission of a pre-anneal step in the heat treatment. We are evaluating the electrical properties of the coil, the microstructure and short-sample superconducting performance of cut-off samples of current leads to determine the extent of damage to the performance of the windings. Results of those tests and plans for construction of TAMU3 will be presented.

  19. Optical Signatures from Magnetic 2-D Electron Gases in High Magnetic Fields to 60 Tesla

    SciTech Connect

    Crooker, S.A.; Kikkawa, J.M.; Awschalom, D.D.; Smorchikova, I.P.; Samarth, N.

    1998-11-08

    We present experiments in the 60 Tesla Long-Pulse magnet at the Los Alamos National High Magnetic Field Lab (NHMFL) focusing on the high-field, low temperature photoluminescence (PL) from modulation-doped ZnSe/Zn(Cd,Mn)Se single quantum wells. High-speed charge-coupled array detectors and the long (2 second) duration of the magnet pulse permit continuous acquisition of optical spectra throughout a single magnet shot. High-field PL studies of the magnetic 2D electron gases at temperatures down to 350mK reveal clear intensity oscillations corresponding to integer quantum Hall filling factors, from which we determine the density of the electron gas. At very high magnetic fields, steps in the PL energy are observed which correspond to the partial unlocking of antiferromagnetically bound pairs of Mn2+ spins.

  20. Parameter study of the VUV-FEL at the Tesla Test Facility

    SciTech Connect

    Brefeld, W.; Faatz, B.

    1995-12-31

    In this contribution we present a detailed study of the influence of the electron beam and machine parameters on the performance of the TTF VUV FEL, which is in its design stage at DESY. The TTF FEL will be a 6 nm SASE device operating with the beam provided by the Tesla Test Facility superconducting linac, driven by an rf photcathode gun. The FEL output power and saturation length have been assessed with the use of different 2D3-D steady state simulation codes. The parameter range over which the FEL would reach saturation within the specified undulator length of 25 to 30 m have been determined and checked against semi-analytical expressions.

  1. Shot noise startup of the 6 NM SASE FEL at the Tesla Test Facility

    SciTech Connect

    Pierini, P.; Fawley, W.M.

    1995-12-31

    We present here an analysis of the shot noise startup of the 6 nm SASE FEI proposal at the TESLA Test Facility in DESY The statistical of the saturation length and output power due to the intrinsic randomness of the noise startup are investigated with the use of the 2D time dependent code GINGER, that takes into account propagation effects and models shot noise. We then provide estimates for the spectral contents and linewidth of the emitted radiation and describe its spiking characteristics. The output radiation will develop superradiant spikes seeded by the shot noise in the electron beam, which can entrance the average emitted power at the expense of some spectral broadening.

  2. Magnet Design and Analysis of a 40 Tesla Long Pulse System Energized by a Battery Bank

    NASA Astrophysics Data System (ADS)

    Lv, Y. L.; Peng, T.; Wang, G. B.; Ding, T. H.; Han, X. T.; Pan, Y.; Li, L.

    2013-03-01

    A 40 tesla long pulse magnet and a battery bank as the power supply have been designed. This is now under construction at the Wuhan National High Magnetic Field Center. The 22 mm bore magnet will generate smooth pulses with duration 1 s and rise time 0.5 s. The battery bank consists of 945 12V/200 Ah lead-acid battery cells. The magnet and battery bank were optimized by codes developed in-house and by ANSYS. The coil was made from soft copper with internal reinforcement by fiber-epoxy composite; it is divided into two sections connected in series. The inner section consists of helix coils with each layer reinforced by Zylon composite. The outer section will be wound from copper sheet and externally reinforced by carbon fiber composite.

  3. A test of a 2 Tesla superconducting transmission line magnet system

    SciTech Connect

    Piekarz, Henryk; Carcagno, Ruben; Claypool, Brad; Foster, George W.; Hays, Steven L.; Huang, Yuenian; Kashikhin, Vladimir; Malamud, Ernest; Mazur, Peter O.; Nehring, Roger; Oleck, Andrew; Rabehl, Roger; Schlabach, Phil; Sylvester, Cosmore; Velev, Gueorgui; Volk, James; Wake, Masayoshi; /KEK, Tsukuba

    2005-09-01

    Superconducting transmission line magnet test system for an injector accelerator of a staged VLHC proton-proton colliding beam accelerator has been built and operated at Fermilab. The 1.5 m long, twin-aperture, combined function dipole magnet of 2 Tesla field is excited by a single turn 100 kA transmission line superconductor. The 100 kA dc current is generated using dc-dc switching converters powered by a bulk 240 kW supply. A pair of horizontally placed conventional leads facilitates transfer of this current to the magnet transmission line superconductor operating at liquid helium temperature. Fabrication of magnet components and magnet assembly work are described. The magnet test system and its operation are presented, and the performance is summarized.

  4. Increasing Reliability with Wireless Instrumentation Systems from Space Shuttle to 'Fly-By-Wireless'

    NASA Technical Reports Server (NTRS)

    Studor, George

    2004-01-01

    This slide presentation discusses some of the requirements to allow for "Fly by Wireless". Included in the discussion are: a review of new technologies by decades starting with the 1930's and going through the current decade, structural health monitoring, the requisite system designs, and the vision of flying by wireless.

  5. Low-noise nano superconducting quantum interference device operating in Tesla magnetic fields.

    PubMed

    Schwarz, Tobias; Nagel, Joachim; Wölbing, Roman; Kemmler, Matthias; Kleiner, Reinhold; Koelle, Dieter

    2013-01-22

    Superconductivity in the cuprate YBa(2)Cu(3)O(7) (YBCO) persists up to huge magnetic fields (B) up to several tens of Teslas, and sensitive direct current (dc) superconducting quantum interference devices (SQUIDs) can be realized in epitaxially grown YBCO films by using grain boundary Josephson junctions (GBJs). Here we present the realization of high-quality YBCO nanoSQUIDs, patterned by focused ion beam milling. We demonstrate low-noise performance of such a SQUID up to B = 1 T applied parallel to the plane of the SQUID loop at the temperature T = 4.2 K. The GBJs are shunted by a thin Au layer to provide nonhysteretic current voltage characteristics, and the SQUID incorporates a 90 nm wide constriction which is used for on-chip modulation of the magnetic flux through the SQUID loop. The white flux noise of the device increases only slightly from 1.3 μΦ(0)/(Hz)(1/2) at B = 0 to 2.3 μΦ(0)/(Hz))(1/2) at 1 T. Assuming that a point-like magnetic particle with magnetization in the plane of the SQUID loop is placed directly on top of the constriction and taking into account the geometry of the SQUID, we calculate a spin sensitivity S(μ)(1/2) = 62 μ(B)/(Hz))(1/2) at B = 0 and 110 μ(B)/(Hz))(1/2) at 1 T. The demonstration of low noise of such a SQUID in Tesla fields is a decisive step toward utilizing the full potential of ultrasensitive nanoSQUIDs for direct measurements of magnetic hysteresis curves of magnetic nanoparticles and molecular magnets. PMID:23252846

  6. A 10 Kelvin 3 Tesla Magnet for Space Flight ADR Systems

    NASA Technical Reports Server (NTRS)

    Tuttle, Jim; Shirron, Peter; Canavan, Edgar; DiPirro, Michael; Riall, Sara; Pourrahimi, Shahin

    2003-01-01

    Many future space flight missions are expected to use adiabatic demagnetization refrigerators (ADRs) to reach detector operating temperatures well below one Kelvin. The goal is to operate each ADR with a mechanical cooler as its heat sink, thus avoiding the use of liquid cryogens. Although mechanical coolers are being developed to operate at temperatures of 6 Kelvin and below, there is a large efficiency cost associated with operating them at the bottom of their temperature range. For the multi-stage ADR system being developed at Goddard Space Flight Center, the goal is to operate with a 10 Kelvin mechanical cooler heat sink. With currently available paramagnetic materials, the highest temperature ADR stage in such a system will require a magnetic field of approximately three Tesla. Thus the goal is to develop a small, lightweight three Tesla superconducting magnet for operation at 10 Kelvin. It is important that this magnet have a low current/field ratio. Because traditional NbTi magnets do not operate safely above about six Kelvin, a magnet with a higher Tc is required. The primary focus has been on Nb3Sn magnets. Since standard Nb3Sn wire must be coated with thick insulation, wound on a magnet mandrel and then reacted, standard Nb,Sn magnets are quite heavy and require high currents Superconducting Systems developed a Nb3Sn wire which can be drawn down to small diameter, reacted, coated with thin insulation and then wound on a small diameter coil form. By using this smaller wire and operating closer to the wire s critical current, it should be possible to reduce the mass and operating current of 10 Kelvin magnets. Using this "react-then-wind" technology, Superconducting Systems has produced prototype 10 Kelvin magnets. This paper describes the development and testing of these magnets and discusses the outlook for including 10 Kelvin magnets on space-flight missions.

  7. Intrusion detection and monitoring for wireless networks.

    SciTech Connect

    Thomas, Eric D.; Van Randwyk, Jamie A.; Lee, Erik J.; Stephano, Amanda; Tabriz, Parisa; Pelon, Kristen; McCoy, Damon (University of Colorado, Boulder); Lodato, Mark; Hemingway, Franklin; Custer, Ryan P.; Averin, Dimitry; Franklin, Jason; Kilman, Dominique Marie

    2005-11-01

    Wireless computer networks are increasing exponentially around the world. They are being implemented in both the unlicensed radio frequency (RF) spectrum (IEEE 802.11a/b/g) and the licensed spectrum (e.g., Firetide [1] and Motorola Canopy [2]). Wireless networks operating in the unlicensed spectrum are by far the most popular wireless computer networks in existence. The open (i.e., proprietary) nature of the IEEE 802.11 protocols and the availability of ''free'' RF spectrum have encouraged many producers of enterprise and common off-the-shelf (COTS) computer networking equipment to jump into the wireless arena. Competition between these companies has driven down the price of 802.11 wireless networking equipment and has improved user experiences with such equipment. The end result has been an increased adoption of the equipment by businesses and consumers, the establishment of the Wi-Fi Alliance [3], and widespread use of the Alliance's ''Wi-Fi'' moniker to describe these networks. Consumers use 802.11 equipment at home to reduce the burden of running wires in existing construction, facilitate the sharing of broadband Internet services with roommates or neighbors, and increase their range of ''connectedness''. Private businesses and government entities (at all levels) are deploying wireless networks to reduce wiring costs, increase employee mobility, enable non-employees to access the Internet, and create an added revenue stream to their existing business models (coffee houses, airports, hotels, etc.). Municipalities (Philadelphia; San Francisco; Grand Haven, MI) are deploying wireless networks so they can bring broadband Internet access to places lacking such access; offer limited-speed broadband access to impoverished communities; offer broadband in places, such as marinas and state parks, that are passed over by traditional broadband providers; and provide themselves with higher quality, more complete network coverage for use by emergency responders and other

  8. Hierarchical Clustering of Shotgun Proteomics Data

    PubMed Central

    Koskinen, Ville R.; Emery, Patrick A.; Creasy, David M.; Cottrell, John S.

    2011-01-01

    A new result report for Mascot search results is described. A greedy set cover algorithm is used to create a minimal set of proteins, which is then grouped into families on the basis of shared peptide matches. Protein families with multiple members are represented by dendrograms, generated by hierarchical clustering using the score of the nonshared peptide matches as a distance metric. The peptide matches to the proteins in a family can be compared side by side to assess the experimental evidence for each protein. If the evidence for a particular family member is considered inadequate, the dendrogram can be cut to reduce the number of distinct family members. PMID:21447708

  9. Structural analysis of hierarchically organized zeolites

    NASA Astrophysics Data System (ADS)

    Mitchell, Sharon; Pinar, Ana B.; Kenvin, Jeffrey; Crivelli, Paolo; Kärger, Jörg; Pérez-Ramírez, Javier

    2015-10-01

    Advances in materials synthesis bring about many opportunities for technological applications, but are often accompanied by unprecedented complexity. This is clearly illustrated by the case of hierarchically organized zeolite catalysts, a class of crystalline microporous solids that has been revolutionized by the engineering of multilevel pore architectures, which combine unique chemical functionality with efficient molecular transport. Three key attributes, the crystal, the pore and the active site structure, can be expected to dominate the design process. This review examines the adequacy of the palette of techniques applied to characterize these distinguishing features and their catalytic impact.

  10. Structural analysis of hierarchically organized zeolites.

    PubMed

    Mitchell, Sharon; Pinar, Ana B; Kenvin, Jeffrey; Crivelli, Paolo; Kärger, Jörg; Pérez-Ramírez, Javier

    2015-01-01

    Advances in materials synthesis bring about many opportunities for technological applications, but are often accompanied by unprecedented complexity. This is clearly illustrated by the case of hierarchically organized zeolite catalysts, a class of crystalline microporous solids that has been revolutionized by the engineering of multilevel pore architectures, which combine unique chemical functionality with efficient molecular transport. Three key attributes, the crystal, the pore and the active site structure, can be expected to dominate the design process. This review examines the adequacy of the palette of techniques applied to characterize these distinguishing features and their catalytic impact. PMID:26482337

  11. Hierarchical modelling of mobile, seeing robots

    NASA Technical Reports Server (NTRS)

    Luh, Cheng-Jye; Zeigler, Bernard P.

    1990-01-01

    This paper describes the implementation of a hierarchical robot simulation which supports the design of robots with vision and mobility. A seeing robot applies a classification expert system for visual identification of laboratory objects. The visual data acquisition algorithm used by the robot vision system has been developed to exploit multiple viewing distances and perspectives. Several different simulations have been run testing the visual logic in a laboratory environment. Much work remains to integrate the vision system with the rest of the robot system.

  12. Hierarchical nucleus segmentation in digital pathology images

    PubMed Central

    Gao, Yi; Ratner, Vadim; Zhu, Liangjia; Diprima, Tammy; Kurc, Tahsin; Tannenbaum, Allen; Saltz, Joel

    2016-01-01

    Extracting nuclei is one of the most actively studied topic in the digital pathology researches. Most of the studies directly search the nuclei (or seeds for the nuclei) from the finest resolution available. While the richest information has been utilized by such approaches, it is sometimes difficult to address the heterogeneity of nuclei in different tissues. In this work, we propose a hierarchical approach which starts from the lower resolution level and adaptively adjusts the parameters while progressing into finer and finer resolution. The algorithm is tested on brain and lung cancers images from The Cancer Genome Atlas data set. PMID:27375315

  13. Technique for fast and efficient hierarchical clustering

    DOEpatents

    Stork, Christopher

    2013-10-08

    A fast and efficient technique for hierarchical clustering of samples in a dataset includes compressing the dataset to reduce a number of variables within each of the samples of the dataset. A nearest neighbor matrix is generated to identify nearest neighbor pairs between the samples based on differences between the variables of the samples. The samples are arranged into a hierarchy that groups the samples based on the nearest neighbor matrix. The hierarchy is rendered to a display to graphically illustrate similarities or differences between the samples.

  14. Modified Recursive Hierarchical Segmentation of Data

    NASA Technical Reports Server (NTRS)

    Tilton, James C.

    2006-01-01

    An algorithm and a computer program that implements the algorithm that performs recursive hierarchical segmentation (RHSEG) of data have been developed. While the current implementation is for two-dimensional data having spatial characteristics (e.g., image, spectral, or spectral-image data), the generalized algorithm also applies to three-dimensional or higher dimensional data and also to data with no spatial characteristics. The algorithm and software are modified versions of a prior RHSEG algorithm and software, the outputs of which often contain processing-window artifacts including, for example, spurious segmentation-image regions along the boundaries of processing-window edges.

  15. Flow and transport in hierarchically fractured systems

    SciTech Connect

    Karasaki, K.

    1993-01-01

    Preliminary results indicate that flow in the saturated zone at Yucca Mountain is controlled by fractures. A current conceptual model assumes that the flow in the fracture system can be approximately by a three-dimensionally interconnected network of linear conduits. The overall flow system of rocks at Yucca Mountain is considered to consist of hierarchically structured heterogeneous fracture systems of multiple scales. A case study suggests that it is more appropriate to use the flow parameters of the large fracture system for predicting the first arrival time, rather than using the bulk average parameters of the total system.

  16. Flow and transport in hierarchically fractured systems

    SciTech Connect

    Karasaki, K.

    1993-12-31

    Preliminary results indicate that flow in the saturated zone at Yucca Mountain is controlled by fractures. A current conceptual model assumes that the flow in the fracture system can be approximated by a three-dimensionally interconnected network of linear conduits. The overall flow system of rocks at Yucca Mountain is considered to consist of hierarchically structured heterogeneous fracture systems of multiple scales. A case study suggests that it is more appropriate to use the flow parameters of the large fracture system for predicting the first arrival time, rather than using the bulk average parameters of the total system.

  17. Structural analysis of hierarchically organized zeolites

    PubMed Central

    Mitchell, Sharon; Pinar, Ana B.; Kenvin, Jeffrey; Crivelli, Paolo; Kärger, Jörg; Pérez-Ramírez, Javier

    2015-01-01

    Advances in materials synthesis bring about many opportunities for technological applications, but are often accompanied by unprecedented complexity. This is clearly illustrated by the case of hierarchically organized zeolite catalysts, a class of crystalline microporous solids that has been revolutionized by the engineering of multilevel pore architectures, which combine unique chemical functionality with efficient molecular transport. Three key attributes, the crystal, the pore and the active site structure, can be expected to dominate the design process. This review examines the adequacy of the palette of techniques applied to characterize these distinguishing features and their catalytic impact. PMID:26482337

  18. OIT Wireless Telemetry for Industrial Applications

    SciTech Connect

    Manges, WW

    2002-09-03

    The need for advanced wireless technology has been identified in the National Research Council publication (1) ''Manufacturing Process Controls for the Industries of the Future as a Critical Technology for the Future''. The deployment challenges to be overcome in order for wireless to be a viable option include: (1) eliminating interference (assuring reliable communications); (2) easing the deployment of intelligent, wireless sensors; (3) developing reliable networks (robust architectures); (4) developing remote power (long-lasting and reliable); and (5) developing standardized communication protocols. This project demonstrated the feasibility of robust wireless sensor networks that could meet these requirements for the harsh environments common to the DOE/OIT Industries of the Future. It resulted in a wireless test bed that was demonstrated in a paper mill and a steel plant. The test bed illustrated key protocols and components that would be required in a real-life, wireless network. The technologies for low power connectivity developed and demonstrated at the plant eased fears that the radios would interfere with existing control equipment. The same direct sequence, spread spectrum (DSSS) technology that helped assure the reliability of the connection also demonstrated that wireless communication was feasible in these plants without boosting the transmitted power to dangerous levels. Our experience and research have indicated that two key parameters are of ultimate importance: (1) reliability and (2) inter-system compatibility. Reliability is the key to immediate acceptance among industrial users. The importance cannot be overstated, because users will not tolerate an unreliable information network. A longer term issue that is at least as important as the reliability of a single system is the inter-system compatibility between these wireless sensor networks and other wireless systems that are part of our industries. In the long run, the ability of wireless sensor

  19. Pareto-optimal clustering scheme using data aggregation for wireless sensor networks

    NASA Astrophysics Data System (ADS)

    Azad, Puneet; Sharma, Vidushi

    2015-07-01

    The presence of cluster heads (CHs) in a clustered wireless sensor network (WSN) leads to improved data aggregation and enhanced network lifetime. Thus, the selection of appropriate CHs in WSNs is a challenging task, which needs to be addressed. A multicriterion decision-making approach for the selection of CHs is presented using Pareto-optimal theory and technique for order preference by similarity to ideal solution (TOPSIS) methods. CHs are selected using three criteria including energy, cluster density and distance from the sink. The overall network lifetime in this method with 50% data aggregation after simulations is 81% higher than that of distributed hierarchical agglomerative clustering in similar environment and with same set of parameters. Optimum number of clusters is estimated using TOPSIS technique and found to be 9-11 for effective energy usage in WSNs.

  20. Wireless integrated network sensors: toward low-cost and robust self-organizing security networks

    NASA Astrophysics Data System (ADS)

    Pottie, Gregory J.; Clare, Loren P.

    1999-01-01

    A very important benefit of continuing advances in CMOS IC technology is the ability to construct a wide variety of micro electrical mechanical systems (MEMS), including sensors and RF components. These building blocks enable the fabrication of complete systems in a low-cost module, which include sensing, signal processing, and wireless communications. Together with innovative and focused network design techniques that will make possible simple deployment and sustained low- power operation, the small size and cost can be enabling for a very large number of law enforcement and security applications, including remote reconnaissance and security zones ranging from persons to borders. We outline how the application can be exploited in the network design to enable sustained low-power operation. In particular, extensive information processing at nodes, hierarchical decision-making, and energy conserving routing and network topology management methods will be employed in the networks under development.

  1. Prevalence of and Epidemic Spreading on Hierarchical Networks

    NASA Astrophysics Data System (ADS)

    He, Jiankui; Deem, Michael

    2009-03-01

    Recent studies show that real networks are organized in a modular or even hierarchical fashion. However, there is no clear mathematical definition of hierarchy and current studies do not tell us the degree to which a network is hierarchical. In this talk, we will discuss a quantitative measurement of hierarchy. We find that networks of protein interactions, metabolic pathways, electronic circuits, power grids, and emails display strong hierarchy compared with networks generated at random or scale free networks of the Barab'asi-Albert model. Further, we investigated the spread of virus in hierarchical networks. Viral spread on hierarchical networks displays quite different pattern from scale free and random networks.

  2. Fractal image perception provides novel insights into hierarchical cognition.

    PubMed

    Martins, M J; Fischmeister, F P; Puig-Waldmüller, E; Oh, J; Geissler, A; Robinson, S; Fitch, W T; Beisteiner, R

    2014-08-01

    Hierarchical structures play a central role in many aspects of human cognition, prominently including both language and music. In this study we addressed hierarchy in the visual domain, using a novel paradigm based on fractal images. Fractals are self-similar patterns generated by repeating the same simple rule at multiple hierarchical levels. Our hypothesis was that the brain uses different resources for processing hierarchies depending on whether it applies a "fractal" or a "non-fractal" cognitive strategy. We analyzed the neural circuits activated by these complex hierarchical patterns in an event-related fMRI study of 40 healthy subjects. Brain activation was compared across three different tasks: a similarity task, and two hierarchical tasks in which subjects were asked to recognize the repetition of a rule operating transformations either within an existing hierarchical level, or generating new hierarchical levels. Similar hierarchical images were generated by both rules and target images were identical. We found that when processing visual hierarchies, engagement in both hierarchical tasks activated the visual dorsal stream (occipito-parietal cortex, intraparietal sulcus and dorsolateral prefrontal cortex). In addition, the level-generating task specifically activated circuits related to the integration of spatial and categorical information, and with the integration of items in contexts (posterior cingulate cortex, retrosplenial cortex, and medial, ventral and anterior regions of temporal cortex). These findings provide interesting new clues about the cognitive mechanisms involved in the generation of new hierarchical levels as required for fractals. PMID:24699014

  3. NASA Lunar Base Wireless System Propagation Analysis

    NASA Technical Reports Server (NTRS)

    Hwu, Shian U.; Upanavage, Matthew; Sham, Catherine C.

    2007-01-01

    There have been many radio wave propagation studies using both experimental and theoretical techniques over the recent years. However, most of studies have been in support of commercial cellular phone wireless applications. The signal frequencies are mostly at the commercial cellular and Personal Communications Service bands. The antenna configurations are mostly one on a high tower and one near the ground to simulate communications between a cellular base station and a mobile unit. There are great interests in wireless communication and sensor systems for NASA lunar missions because of the emerging importance of establishing permanent lunar human exploration bases. Because of the specific lunar terrain geometries and RF frequencies of interest to the NASA missions, much of the published literature for the commercial cellular and PCS bands of 900 and 1800 MHz may not be directly applicable to the lunar base wireless system and environment. There are various communication and sensor configurations required to support all elements of a lunar base. For example, the communications between astronauts, between astronauts and the lunar vehicles, between lunar vehicles and satellites on the lunar orbits. There are also various wireless sensor systems among scientific, experimental sensors and data collection ground stations. This presentation illustrates the propagation analysis of the lunar wireless communication and sensor systems taking into account the three dimensional terrain multipath effects. It is observed that the propagation characteristics are significantly affected by the presence of the lunar terrain. The obtained results indicate the lunar surface material, terrain geometry and antenna location are the important factors affecting the propagation characteristics of the lunar wireless systems. The path loss can be much more severe than the free space propagation and is greatly affected by the antenna height, surface material and operating frequency. The

  4. Wireless Technologies in Support of ISS Experimentation and Operations

    NASA Technical Reports Server (NTRS)

    Wagner, Raymond; Fink, Patrick

    2012-01-01

    Presentation reviews: (1) Wireless Communications (a) Internal (b) External (2) RFID (Radio Frequency Identification) (a) Existing and R&D (3) Wireless Sensor Networks (a) Existing and R&D (4) Ultra-Wide Band (UWB) (a) R&D

  5. 1. TUCKERTON WIRELESS, RADIO ROAD, PERSPECTIVE VIEW OF CONCRETE FOUNDATION ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. TUCKERTON WIRELESS, RADIO ROAD, PERSPECTIVE VIEW OF CONCRETE FOUNDATION OF RADIO STANTION WITH WIRELESS BUILDING AND SMOKESTACK IN BACKGROUND, LOOKING NORTH - Town of Tuckerton, U.S. Highway 9 & County Road 539, Tuckerton, Ocean County, NJ

  6. Wi-GIM system: a new wireless sensor network (WSN) for accurate ground instability monitoring

    NASA Astrophysics Data System (ADS)

    Mucchi, Lorenzo; Trippi, Federico; Schina, Rosa; Fornaciai, Alessandro; Gigli, Giovanni; Nannipieri, Luca; Favalli, Massimiliano; Marturia Alavedra, Jordi; Intrieri, Emanuele; Agostini, Andrea; Carnevale, Ennio; Bertolini, Giovanni; Pizziolo, Marco; Casagli, Nicola

    2016-04-01

    Landslides are among the most serious and common geologic hazards around the world. Their impact on human life is expected to increase in the next future as a consequence of human-induced climate change as well as the population growth in proximity of unstable slopes. Therefore, developing better performing technologies for monitoring landslides and providing local authorities with new instruments able to help them in the decision making process, is becoming more and more important. The recent progresses in Information and Communication Technologies (ICT) allow us to extend the use of wireless technologies in landslide monitoring. In particular, the developments in electronics components have permitted to lower the price of the sensors and, at the same time, to actuate more efficient wireless communications. In this work we present a new wireless sensor network (WSN) system, designed and developed for landslide monitoring in the framework of EU Wireless Sensor Network for Ground Instability Monitoring - Wi-GIM project (LIFE12 ENV/IT/001033). We show the preliminary performance of the Wi-GIM system after the first period of monitoring on the active Roncovetro Landslide and on a large subsiding area in the neighbourhood of Sallent village. The Roncovetro landslide is located in the province of Reggio Emilia (Italy) and moved an inferred volume of about 3 million cubic meters. Sallent village is located at the centre of the Catalan evaporitic basin in Spain. The Wi-GIM WSN monitoring system consists of three levels: 1) Master/Gateway level coordinates the WSN and performs data aggregation and local storage; 2) Master/Server level takes care of acquiring and storing data on a remote server; 3) Nodes level that is based on a mesh of peripheral nodes, each consisting in a sensor board equipped with sensors and wireless module. The nodes are located in the landslide ground perimeter and are able to create an ad-hoc WSN. The location of each sensor on the ground is

  7. Efficient scalable algorithms for hierarchically semiseparable matrices

    SciTech Connect

    Wang, Shen; Xia, Jianlin; Situ, Yingchong; Hoop, Maarten V. de

    2011-09-14

    Hierarchically semiseparable (HSS) matrix algorithms are emerging techniques in constructing the superfast direct solvers for both dense and sparse linear systems. Here, we develope a set of novel parallel algorithms for the key HSS operations that are used for solving large linear systems. These include the parallel rank-revealing QR factorization, the HSS constructions with hierarchical compression, the ULV HSS factorization, and the HSS solutions. The HSS tree based parallelism is fully exploited at the coarse level. The BLACS and ScaLAPACK libraries are used to facilitate the parallel dense kernel operations at the ne-grained level. We have appplied our new parallel HSS-embedded multifrontal solver to the anisotropic Helmholtz equations for seismic imaging, and were able to solve a linear system with 6.4 billion unknowns using 4096 processors, in about 20 minutes. The classical multifrontal solver simply failed due to high demand of memory. To our knowledge, this is the first successful demonstration of employing the HSS algorithms in solving the truly large-scale real-world problems. Our parallel strategies can be easily adapted to the parallelization of the other rank structured methods.

  8. A hierarchical exact accelerated stochastic simulation algorithm

    PubMed Central

    Orendorff, David; Mjolsness, Eric

    2012-01-01

    A new algorithm, “HiER-leap” (hierarchical exact reaction-leaping), is derived which improves on the computational properties of the ER-leap algorithm for exact accelerated simulation of stochastic chemical kinetics. Unlike ER-leap, HiER-leap utilizes a hierarchical or divide-and-conquer organization of reaction channels into tightly coupled “blocks” and is thereby able to speed up systems with many reaction channels. Like ER-leap, HiER-leap is based on the use of upper and lower bounds on the reaction propensities to define a rejection sampling algorithm with inexpensive early rejection and acceptance steps. But in HiER-leap, large portions of intra-block sampling may be done in parallel. An accept/reject step is used to synchronize across blocks. This method scales well when many reaction channels are present and has desirable asymptotic properties. The algorithm is exact, parallelizable and achieves a significant speedup over the stochastic simulation algorithm and ER-leap on certain problems. This algorithm offers a potentially important step towards efficient in silico modeling of entire organisms. PMID:23231214

  9. Hierarchical link clustering algorithm in networks

    NASA Astrophysics Data System (ADS)

    Bodlaj, Jernej; Batagelj, Vladimir

    2015-06-01

    Hierarchical network clustering is an approach to find tightly and internally connected clusters (groups or communities) of nodes in a network based on its structure. Instead of nodes, it is possible to cluster links of the network. The sets of nodes belonging to clusters of links can overlap. While overlapping clusters of nodes are not always expected, they are natural in many applications. Using appropriate dissimilarity measures, we can complement the clustering strategy to consider, for example, the semantic meaning of links or nodes based on their properties. We propose a new hierarchical link clustering algorithm which in comparison to existing algorithms considers node and/or link properties (descriptions, attributes) of the input network alongside its structure using monotonic dissimilarity measures. The algorithm determines communities that form connected subnetworks (relational constraint) containing locally similar nodes with respect to their description. It is only implicitly based on the corresponding line graph of the input network, thus reducing its space and time complexities. We investigate both complexities analytically and statistically. Using provided dissimilarity measures, our algorithm can, in addition to the general overlapping community structure of input networks, uncover also related subregions inside these communities in a form of hierarchy. We demonstrate this ability on real-world and artificial network examples.

  10. Hierarchical majorana neutrinos from democratic mass matrices

    NASA Astrophysics Data System (ADS)

    Yang, Masaki J. S.

    2016-09-01

    In this paper, we obtain the light neutrino masses and mixings consistent with the experiments, in the democratic texture approach. The essential ansatz is that νRi are assumed to transform as "right-handed fields" 2R +1R under the S3L ×S3R symmetry. The symmetry breaking terms are assumed to be diagonal and hierarchical. This setup only allows the normal hierarchy of the neutrino mass, and excludes both of inverted hierarchical and degenerated neutrinos. Although the neutrino sector has nine free parameters, several predictions are obtained at the leading order. When we neglect the smallest parameters ζν and ζR, all components of the mixing matrix UPMNS are expressed by the masses of light neutrinos and charged leptons. From the consistency between predicted and observed UPMNS, we obtain the lightest neutrino masses m1 = (1.1 → 1.4) meV, and the effective mass for the double beta decay ≃ 4.5 meV.

  11. HIERARCHICAL STAR FORMATION IN NEARBY LEGUS GALAXIES

    SciTech Connect

    Elmegreen, Debra Meloy; Elmegreen, Bruce G.; Adamo, Angela; Gouliermis, Dimitrios A.; Aloisi, Alessandra; Bright, Stacey N.; Cignoni, Michele; Lee, Janice; Sabbi, Elena; Andrews, Jennifer; Calzetti, Daniela; Annibali, Francesca; Evans, Aaron S.; Johnson, Kelsey; Gallagher III, John S.; Grebel, Eva K.; Hunter, Deidre A.; Kim, Hwihyun; Smith, Linda J.; Thilker, David; and others

    2014-05-20

    Hierarchical structure in ultraviolet images of 12 late-type LEGUS galaxies is studied by determining the numbers and fluxes of nested regions as a function of size from ∼1 to ∼200 pc, and the number as a function of flux. Two starburst dwarfs, NGC 1705 and NGC 5253, have steeper number-size and flux-size distributions than the others, indicating high fractions of the projected areas filled with star formation. Nine subregions in seven galaxies have similarly steep number-size slopes, even when the whole galaxies have shallower slopes. The results suggest that hierarchically structured star-forming regions several hundred parsecs or larger represent common unit structures. Small galaxies dominated by only a few of these units tend to be starbursts. The self-similarity of young stellar structures down to parsec scales suggests that star clusters form in the densest parts of a turbulent medium that also forms loose stellar groupings on larger scales. The presence of super star clusters in two of our starburst dwarfs would follow from the observed structure if cloud and stellar subregions more readily coalesce when self-gravity in the unit cell contributes more to the total gravitational potential.

  12. A Hierarchical Bayesian Model for Crowd Emotions

    PubMed Central

    Urizar, Oscar J.; Baig, Mirza S.; Barakova, Emilia I.; Regazzoni, Carlo S.; Marcenaro, Lucio; Rauterberg, Matthias

    2016-01-01

    Estimation of emotions is an essential aspect in developing intelligent systems intended for crowded environments. However, emotion estimation in crowds remains a challenging problem due to the complexity in which human emotions are manifested and the capability of a system to perceive them in such conditions. This paper proposes a hierarchical Bayesian model to learn in unsupervised manner the behavior of individuals and of the crowd as a single entity, and explore the relation between behavior and emotions to infer emotional states. Information about the motion patterns of individuals are described using a self-organizing map, and a hierarchical Bayesian network builds probabilistic models to identify behaviors and infer the emotional state of individuals and the crowd. This model is trained and tested using data produced from simulated scenarios that resemble real-life environments. The conducted experiments tested the efficiency of our method to learn, detect and associate behaviors with emotional states yielding accuracy levels of 74% for individuals and 81% for the crowd, similar in performance with existing methods for pedestrian behavior detection but with novel concepts regarding the analysis of crowds. PMID:27458366

  13. Hierarchical approaches to analysis of natural textures

    NASA Astrophysics Data System (ADS)

    Lutsiv, Vadim R.; Malyshev, Igor A.; Novikova, Tatiana A.

    2004-09-01

    The surface textures of natural objects often have the visible fractal-like properties. A similar pattern of texture could be found looking at the forests in the aerial photographs or at the trees in the outdoor scenes when the image spatial resolution was changed. Or the texture patterns are different at different spatial resolution levels in the aerial photographs of villages. It creates the difficulties in image segmentation and object recognition because the levels of spatial resolution necessary to get the homogeneously and correctly labeled texture regions differ for different types of landscape. E.g. if the spatial resolution was sufficient for distinguishing between the textures of agricultural fields, water, and asphalt, the texture labeled areas of forest or suburbs are hardly fragmented, because the texture peculiarities corresponding to two stable levels of texture spatial resolution will be visible in this case. A hierarchical texture analysis could solve this problem, and we did it in two different ways: we performed the texture segmentation simultaneously for several levels of image spatial resolution, or we subjected the texture labeled image of highest spatial resolution to a recurring texture segmentation using the texture cells of larger sizes. The both approaches turned out to be rather fruitful for the aerial photographs as well as for the outdoor images. They generalize and support the hierarchical image analysis technique presented in another our paper. Some of the methods applied were borrowed from the living vision systems.

  14. A neural network with modular hierarchical learning

    NASA Technical Reports Server (NTRS)

    Baldi, Pierre F. (Inventor); Toomarian, Nikzad (Inventor)

    1994-01-01

    This invention provides a new hierarchical approach for supervised neural learning of time dependent trajectories. The modular hierarchical methodology leads to architectures which are more structured than fully interconnected networks. The networks utilize a general feedforward flow of information and sparse recurrent connections to achieve dynamic effects. The advantages include the sparsity of units and connections, the modular organization. A further advantage is that the learning is much more circumscribed learning than in fully interconnected systems. The present invention is embodied by a neural network including a plurality of neural modules each having a pre-established performance capability wherein each neural module has an output outputting present results of the performance capability and an input for changing the present results of the performance capabilitiy. For pattern recognition applications, the performance capability may be an oscillation capability producing a repeating wave pattern as the present results. In the preferred embodiment, each of the plurality of neural modules includes a pre-established capability portion and a performance adjustment portion connected to control the pre-established capability portion.

  15. Improvement in Recursive Hierarchical Segmentation of Data

    NASA Technical Reports Server (NTRS)

    Tilton, James C.

    2006-01-01

    A further modification has been made in the algorithm and implementing software reported in Modified Recursive Hierarchical Segmentation of Data (GSC- 14681-1), NASA Tech Briefs, Vol. 30, No. 6 (June 2006), page 51. That software performs recursive hierarchical segmentation of data having spatial characteristics (e.g., spectral-image data). The output of a prior version of the software contained artifacts, including spurious segmentation-image regions bounded by processing-window edges. The modification for suppressing the artifacts, mentioned in the cited article, was addition of a subroutine that analyzes data in the vicinities of seams to find pairs of regions that tend to lie adjacent to each other on opposite sides of the seams. Within each such pair, pixels in one region that are more similar to pixels in the other region are reassigned to the other region. The present modification provides for a parameter ranging from 0 to 1 for controlling the relative priority of merges between spatially adjacent and spatially non-adjacent regions. At 1, spatially-adjacent-/spatially- non-adjacent-region merges have equal priority. At 0, only spatially-adjacent-region merges (no spectral clustering) are allowed. Between 0 and 1, spatially-adjacent- region merges have priority over spatially- non-adjacent ones.

  16. Hierarchically structured activated carbon for ultracapacitors

    NASA Astrophysics Data System (ADS)

    Kim, Mok-Hwa; Kim, Kwang-Bum; Park, Sun-Min; Roh, Kwang Chul

    2016-02-01

    To resolve the pore-associated bottleneck problem observed in the electrode materials used for ultracapacitors, which inhibits the transport of the electrolyte ions, we designed hierarchically structured activated carbon (HAC) by synthesizing a mesoporous silica template/carbon composite and chemically activating it to simultaneously remove the silica template and increase the pore volume. The resulting HAC had a well-designed, unique porous structure, which allowed for large interfaces for efficient electric double-layer formation. Given the unique characteristics of the HAC, we believe that the developed synthesis strategy provides important insights into the design and fabrication of hierarchical carbon nanostructures. The HAC, which had a specific surface area of 1,957 m2 g-1, exhibited an extremely high specific capacitance of 157 F g-1 (95 F cc-1), as well as a high rate capability. This indicated that it had superior energy storage capability and was thus suitable for use in advanced ultracapacitors.

  17. Bimodal Color Distribution in Hierarchical Galaxy Formation

    NASA Astrophysics Data System (ADS)

    Menci, N.; Fontana, A.; Giallongo, E.; Salimbeni, S.

    2005-10-01

    We show how the observed bimodality in the color distribution of galaxies can be explained in the framework of the hierarchical clustering picture in terms of the interplay between the properties of the merging histories and the feedback/star formation processes in the progenitors of local galaxies. Using a semianalytic model of hierarchical galaxy formation, we compute the color distributions of galaxies with different luminosities and compare them with the observations. Our fiducial model matches the fundamental properties of the observed distributions, namely: (1) the distribution of objects brighter than Mr<~-18 is clearly bimodal, with a fraction of red objects increasing with luminosity; (2) for objects brighter than Mr<~-21, the color distribution is dominated by red objects with color u-r~2.2-2.4 (3) the spread on the distribution of the red population is smaller than that of the blue population; (4) the fraction of red galaxies is larger in denser environments, even for low-luminosity objects; and (5) the bimodality in the distribution persists up to z~1.5. We discuss the role of the different physical processes included in the model in producing the above results.

  18. Hierarchical structures in a turbulent pipe flow

    NASA Astrophysics Data System (ADS)

    She, Zhen-Su; Zou, Zhengping; Zhu, Yuanjie; Zhou, Mingde

    2003-11-01

    Statistical structures of a series of longitudinal velocity fluctuation signals at different distances (10hierarchical structural (HS) model. The so-called beta-test and gamma-test are designed to study the correlation between intermittent structures of different intensities and the similarity property of the most intense structures. It is shown that at all locations the velocity fluctuations satisfy the She-Leveque hierarchical symmetry (She and Leveque, 1994). The measured HS parameters, beta and gamma, are interpreted in a fluid structure dynamics context. For instance, intense anisotropic fluid structures generated near the wall show smaller gamma and beta. As turbulence migrates into the logarithmic region, small-scale motions are generated by an energy cascade and large-scale organized structures emerge with a less singular character than the most intermittent structures of isotropic turbulence. At the center, turbulence is nearly isotropic, and beta and gamma are close to the 1994 She-Leveque predictions. A transition is observed from the logarithmic region to the center in which gamma drops and the large-scale organized structures break down. We speculate that it is due to the growing eddy viscosity effects of widely spread turbulent fluctuations. Similar effects are observed in the breakdown of the Taylor vortices in a turbulent Couette-Taylor flow at moderately high Reynolds numbers.

  19. Layer like porous materials with hierarchical structure.

    PubMed

    Roth, Wieslaw J; Gil, Barbara; Makowski, Wacław; Marszalek, Bartosz; Eliášová, Pavla

    2016-06-13

    Many chemical compositions produce layered solids consisting of extended sheets with thickness not greater than a few nanometers. The layers are weakly bonded together in a crystal and can be modified into various nanoarchitectures including porous hierarchical structures. Several classes of 2-dimensional (2D) materials have been extensively studied and developed because of their potential usefulness as catalysts and sorbents. They are discussed in this review with focus on clays, layered transition metal oxides, silicates, layered double hydroxides, metal(iv) phosphates and phosphonates, especially zirconium, and zeolites. Pillaring and delamination are the primary methods for structural modification and pore tailoring. The reported approaches are described and compared for the different classes of materials. The methods of characterization include identification by X-ray diffraction and microscopy, pore size analysis and activity assessment by IR spectroscopy and catalytic testing. The discovery of layered zeolites was a fundamental breakthrough that created unprecedented opportunities because of (i) inherent strong acid sites that make them very active catalytically, (ii) porosity through the layers and (iii) bridging of 2D and 3D structures. Approximately 16 different types of layered zeolite structures and modifications have been identified as distinct forms. It is also expected that many among the over 200 recognized zeolite frameworks can produce layered precursors. Additional advances enabled by 2D zeolites include synthesis of layered materials by design, hierarchical structures obtained by direct synthesis and top-down preparation of layered materials from 3D frameworks. PMID:26489452

  20. A self-defining hierarchical data system

    NASA Technical Reports Server (NTRS)

    Bailey, J.

    1992-01-01

    The Self-Defining Data System (SDS) is a system which allows the creation of self-defining hierarchical data structures in a form which allows the data to be moved between different machine architectures. Because the structures are self-defining they can be used for communication between independent modules in a distributed system. Unlike disk-based hierarchical data systems such as Starlink's HDS, SDS works entirely in memory and is very fast. Data structures are created and manipulated as internal dynamic structures in memory managed by SDS itself. A structure may then be exported into a caller supplied memory buffer in a defined external format. This structure can be written as a file or sent as a message to another machine. It remains static in structure until it is reimported into SDS. SDS is written in portable C and has been run on a number of different machine architectures. Structures are portable between machines with SDS looking after conversion of byte order, floating point format, and alignment. A Fortran callable version is also available for some machines.

  1. Oracle Database DBFS Hierarchical Storage Overview

    SciTech Connect

    Rivenes, A

    2011-07-25

    The National Ignition Facility (NIF) at the Lawrence Livermore National Laboratory creates large numbers of images during each shot cycle for the analysis of optics, target inspection and target diagnostics. These images must be readily accessible once they are created and available for the 30 year lifetime of the facility. The Livermore Computing Center (LC) runs a High Performance Storage System (HPSS) that is capable of storing NIF's estimated 1 petabyte of diagnostic images at a fraction of what it would cost NIF to operate its own automated tape library. With Oracle 11g Release 2 database, it is now possible to create an application transparent, hierarchical storage system using the LC's HPSS. Using the Oracle DBMS-LOB and DBMS-DBFS-HS packages a SecureFile LOB can now be archived to storage outside of the database and accessed seamlessly through a DBFS 'link'. NIF has chosen to use this technology to implement a hierarchical store for its image based SecureFile LOBs. Using a modified external store and DBFS links, files are written to and read from a disk 'staging area' using Oracle's backup utility. Database external procedure calls invoke OS based scripts to manage a staging area and the transfer of the backup files between the staging area and the Lab's HPSS.

  2. Hierarchical link clustering algorithm in networks.

    PubMed

    Bodlaj, Jernej; Batagelj, Vladimir

    2015-06-01

    Hierarchical network clustering is an approach to find tightly and internally connected clusters (groups or communities) of nodes in a network based on its structure. Instead of nodes, it is possible to cluster links of the network. The sets of nodes belonging to clusters of links can overlap. While overlapping clusters of nodes are not always expected, they are natural in many applications. Using appropriate dissimilarity measures, we can complement the clustering strategy to consider, for example, the semantic meaning of links or nodes based on their properties. We propose a new hierarchical link clustering algorithm which in comparison to existing algorithms considers node and/or link properties (descriptions, attributes) of the input network alongside its structure using monotonic dissimilarity measures. The algorithm determines communities that form connected subnetworks (relational constraint) containing locally similar nodes with respect to their description. It is only implicitly based on the corresponding line graph of the input network, thus reducing its space and time complexities. We investigate both complexities analytically and statistically. Using provided dissimilarity measures, our algorithm can, in addition to the general overlapping community structure of input networks, uncover also related subregions inside these communities in a form of hierarchy. We demonstrate this ability on real-world and artificial network examples. PMID:26172761

  3. Trabecular bone as a hierarchical material

    NASA Astrophysics Data System (ADS)

    Jasiuk, Iwona

    2004-03-01

    Trabecular bone is studied as a hierarchical material. The analysis includes the experimental characterization of bone's structure, the measurement of its mechanical properties, and the mechanics modeling at several different length scales: nanoscale (under 1 micron, crystal/fiber level), sub-microscale (1-10 microns, single lamella level), microscale (10-500 microns, single trabecula level), and mesoscale (1 mm - 10 cm, trabecular structure, random network of struts or plates). Experiments include the characterization of bone's ultrastructure using SEM (scanning electron microscopy) and TEM (transmission electron microscopy) at nano and sub-microscale levels. In addition, we use the x-ray microtomography, a nondestructive technique, which can provide the three-dimensional details of bone at mesostructural level. Measurements of mechanical properties are done using the MTS machine and nanoindentation apparatus. We use the MTS testing machine to determine constitutive relations of bone at mesoscale and the nanoindentation technique to determine the properties at lower scales. The experimental observations of bone's hierarchical structure are used in the theoretical analysis of bone's mechanical properties. The calculated results are compared with the experimentally measured ones. The material properties are determined at each scale both analytically (using micromechanics theories) and numerically (using a finite element method, a spring network, and beam network approaches). The computational challenges include a complex irregular, random structure at each level, spatial heterogeneity of bone's structure, applicability of separation of scales law, size of the representative volume element, and in general the dependence of properties on specimen size and boundary conditions.

  4. Hierarchical Star Formation in Nearby LEGUS Galaxies

    NASA Astrophysics Data System (ADS)

    Elmegreen, Debra Meloy; Elmegreen, Bruce G.; Adamo, Angela; Aloisi, Alessandra; Andrews, Jennifer; Annibali, Francesca; Bright, Stacey N.; Calzetti, Daniela; Cignoni, Michele; Evans, Aaron S.; Gallagher, John S., III; Gouliermis, Dimitrios A.; Grebel, Eva K.; Hunter, Deidre A.; Johnson, Kelsey; Kim, Hwihyun; Lee, Janice; Sabbi, Elena; Smith, Linda J.; Thilker, David; Tosi, Monica; Ubeda, Leonardo

    2014-05-01

    Hierarchical structure in ultraviolet images of 12 late-type LEGUS galaxies is studied by determining the numbers and fluxes of nested regions as a function of size from ~1 to ~200 pc, and the number as a function of flux. Two starburst dwarfs, NGC 1705 and NGC 5253, have steeper number-size and flux-size distributions than the others, indicating high fractions of the projected areas filled with star formation. Nine subregions in seven galaxies have similarly steep number-size slopes, even when the whole galaxies have shallower slopes. The results suggest that hierarchically structured star-forming regions several hundred parsecs or larger represent common unit structures. Small galaxies dominated by only a few of these units tend to be starbursts. The self-similarity of young stellar structures down to parsec scales suggests that star clusters form in the densest parts of a turbulent medium that also forms loose stellar groupings on larger scales. The presence of super star clusters in two of our starburst dwarfs would follow from the observed structure if cloud and stellar subregions more readily coalesce when self-gravity in the unit cell contributes more to the total gravitational potential.

  5. Standardization of a Hierarchical Transactive Control System

    SciTech Connect

    Hammerstrom, Donald J.; Oliver, Terry V.; Melton, Ronald B.; Ambrosio, Ron

    2010-12-03

    The authors describe work they have conducted toward the generalization and standardization of the transactive control approach that was first demonstrated in the Olympic Peninsula Project for the management of a transmission constraint. The newly generalized approach addresses several potential shortfalls of the prior approach: First, the authors have formalized a hierarchical node structure which defines the nodes and the functional signal pathways between these nodes. Second, by fully generalizing the inputs, outputs, and functional responsibilities of each node, the authors make the approach available to a much wider set of responsive assets and operational objectives. Third, the new, generalized approach defines transactive signals that include the predicted day-ahead future. This predictive feature allows the market-like bids and offers to become resolved iteratively over time, thus allowing the behaviors of responsive assets to be called upon both for the present and as future dispatch decisions are being made. The hierarchical transactive control approach is a key feature of a proposed Pacific Northwest smart grid demonstration.

  6. The concept of a hierarchical cosmos

    NASA Astrophysics Data System (ADS)

    Grujić, P. V.

    2003-10-01

    The idea of a hierachically structured cosmos can be traced back to the Presocratic Hellada. In the fifth century BC Anaxagoras from Clazomenae developed an idea of a sort of fractal material world, by introducing the concept of seeds (spermata), or homoeomeries as Aristotle dubbed it later (Grujić 2001). Anaxagoras ideas have been grossly neglected during the Middle Ages, to be invoked by a number of post-Renaissance thinkers, like Leibniz, Kant, etc, though neither of them referred to their Greek predecessor. But the real resurrections of the hierarchical paradigm started at the beginning of the last century, with Fournier and Charlier (Grujić 2002). Second half of the 20th century witnessed an intensive development of the theoretical models based on the (multi)fractal paradigm, as well as a considerable body of the observational evidence in favour of the hierarchical cosmos (Saar 1988). We overview the state of the art of the cosmological fractal concept, both within the astrophysical (Sylos Labini et al 1998), methodological (Ribeiro 2001) and epistemological (Ribeiro and Videira 1998) context.

  7. A Hierarchical Bayesian Model for Crowd Emotions.

    PubMed

    Urizar, Oscar J; Baig, Mirza S; Barakova, Emilia I; Regazzoni, Carlo S; Marcenaro, Lucio; Rauterberg, Matthias

    2016-01-01

    Estimation of emotions is an essential aspect in developing intelligent systems intended for crowded environments. However, emotion estimation in crowds remains a challenging problem due to the complexity in which human emotions are manifested and the capability of a system to perceive them in such conditions. This paper proposes a hierarchical Bayesian model to learn in unsupervised manner the behavior of individuals and of the crowd as a single entity, and explore the relation between behavior and emotions to infer emotional states. Information about the motion patterns of individuals are described using a self-organizing map, and a hierarchical Bayesian network builds probabilistic models to identify behaviors and infer the emotional state of individuals and the crowd. This model is trained and tested using data produced from simulated scenarios that resemble real-life environments. The conducted experiments tested the efficiency of our method to learn, detect and associate behaviors with emotional states yielding accuracy levels of 74% for individuals and 81% for the crowd, similar in performance with existing methods for pedestrian behavior detection but with novel concepts regarding the analysis of crowds. PMID:27458366

  8. Quark flavor mixings from hierarchical mass matrices

    NASA Astrophysics Data System (ADS)

    Verma, Rohit; Zhou, Shun

    2016-05-01

    In this paper, we extend the Fritzsch ansatz of quark mass matrices while retaining their hierarchical structures and show that the main features of the Cabibbo-Kobayashi-Maskawa (CKM) matrix V, including |V^{}_{us}| ˜eq |V^{}_{cd}|, |V^{}_{cb}| ˜eq |V^{}_{ts}| and |V^{}_{ub}|/|V^{}_{cb}| < |V^{}_{td}|/|V^{}_{ts}|, can be well understood. This agreement is observed especially when the mass matrices have non-vanishing (1, 3) and (3, 1) off-diagonal elements. The phenomenological consequences of these for the allowed texture content and gross structural features of `hierarchical' quark mass matrices are addressed from a model-independent prospective under the assumption of factorizable phases in these. The approximate and analytical expressions of the CKM matrix elements are derived and a detailed analysis reveals that such structures are in good agreement with the observed quark flavor mixing angles and the CP-violating phase at the 1σ level and call upon a further investigation of the realization of these structures from a top-down prospective.

  9. Hierarchical feature selection for erythema severity estimation

    NASA Astrophysics Data System (ADS)

    Wang, Li; Shi, Chenbo; Shu, Chang

    2014-10-01

    At present PASI system of scoring is used for evaluating erythema severity, which can help doctors to diagnose psoriasis [1-3]. The system relies on the subjective judge of doctors, where the accuracy and stability cannot be guaranteed [4]. This paper proposes a stable and precise algorithm for erythema severity estimation. Our contributions are twofold. On one hand, in order to extract the multi-scale redness of erythema, we design the hierarchical feature. Different from traditional methods, we not only utilize the color statistical features, but also divide the detect window into small window and extract hierarchical features. Further, a feature re-ranking step is introduced, which can guarantee that extracted features are irrelevant to each other. On the other hand, an adaptive boosting classifier is applied for further feature selection. During the step of training, the classifier will seek out the most valuable feature for evaluating erythema severity, due to its strong learning ability. Experimental results demonstrate the high precision and robustness of our algorithm. The accuracy is 80.1% on the dataset which comprise 116 patients' images with various kinds of erythema. Now our system has been applied for erythema medical efficacy evaluation in Union Hosp, China.

  10. Hierarchically structured activated carbon for ultracapacitors

    PubMed Central

    Kim, Mok-Hwa; Kim, Kwang-Bum; Park, Sun-Min; Roh, Kwang Chul

    2016-01-01

    To resolve the pore-associated bottleneck problem observed in the electrode materials used for ultracapacitors, which inhibits the transport of the electrolyte ions, we designed hierarchically structured activated carbon (HAC) by synthesizing a mesoporous silica template/carbon composite and chemically activating it to simultaneously remove the silica template and increase the pore volume. The resulting HAC had a well-designed, unique porous structure, which allowed for large interfaces for efficient electric double-layer formation. Given the unique characteristics of the HAC, we believe that the developed synthesis strategy provides important insights into the design and fabrication of hierarchical carbon nanostructures. The HAC, which had a specific surface area of 1,957 m2 g−1, exhibited an extremely high specific capacitance of 157 F g−1 (95 F cc−1), as well as a high rate capability. This indicated that it had superior energy storage capability and was thus suitable for use in advanced ultracapacitors. PMID:26878820

  11. Development of Arduino based wireless control system

    NASA Astrophysics Data System (ADS)

    Sun, Zhuoxiong; Dyke, Shirley J.; Pena, Francisco; Wilbee, Alana

    2015-03-01

    Over the past few decades, considerable attention has been given to structural control systems to mitigate structural vibration under natural hazards such as earthquakes and extreme weather conditions. Traditional wired structural control systems often employ a large amount of cables for communication among sensors, controllers and actuators. In such systems, implementation of wired sensors is usually quite complicated and expensive, especially on large scale structures such as bridges and buildings. To reduce the laborious installation and maintenance cost, wireless control systems (WCSs) are considered as a novel approach for structural vibration control. In this work, a WCS is developed based on the open source Arduino platform. Low cost, low power wireless sensing and communication components are built on the Arduino platform. Structural control algorithms are embedded within the wireless sensor board for feedback control. The developed WCS is first validated through a series of tests. Next, numerical simulations are performed simulating wireless control of a 3-story shear structure equipped with a semi-active control device (MR damper). Finally, experimental studies are carried out implementing the WCS on the 3-story shear structure in the Intelligent Infrastructure Systems Lab (IISL). A hydraulic shake table is used to generate seismic ground motions. The control performance is evaluated with the impact of modeling uncertainties, measurement noises as well as time delay and data loss induced by the wireless network. The developed WCS is shown to be effective in controlling structural vibrations under several historical earthquake ground motions.

  12. Visible Light Wireless Communication for Audio Signals

    NASA Astrophysics Data System (ADS)

    Vibin, A. M.; Prince, Shanthi

    2011-10-01

    In the current century there is an increased demand for broad band wireless access for satisfying different customer needs. These applications requires large amount of frequency resources for its efficient implementation. Radio Frequency techniques, which dominate the current wireless technology, have the limitation of available frequency spectrum that can be used. Researchers identified Optical Wireless Communication as a potential candidate for solving this problem. Studies shows that white light can also be used as a carrier for wireless communication and this area is generally known as Visible Light Communication. The provision of voice data and visual communications to users by using optical wireless has become a key area of research and product development. This paper discusses a novel method for transmission of voice in real time so that the system can be used for both communication and illumination simultaneously. A prototype of the system is implemented successfully and performance analyses are carried out based on the experimental results. SNR and BER calculations for the designed system is done theoretically and simulated. The developed system is having the advantages of very high band width, no interference with adjacent rooms as walls are opaque, no license is required as it doesn't cause electromagnetic interference and communication simultaneously with illumination.

  13. 47 CFR 90.1405 - Shared wireless broadband network.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 5 2012-10-01 2012-10-01 false Shared wireless broadband network. 90.1405... SERVICES PRIVATE LAND MOBILE RADIO SERVICES 700 MHz Public/Private Partnership § 90.1405 Shared wireless broadband network. The Shared Wireless Broadband Network developed by the 700 MHz Public/Private...

  14. Distributed Estimation, Coding, and Scheduling in Wireless Visual Sensor Networks

    ERIC Educational Resources Information Center

    Yu, Chao

    2013-01-01

    In this thesis, we consider estimation, coding, and sensor scheduling for energy efficient operation of wireless visual sensor networks (VSN), which consist of battery-powered wireless sensors with sensing (imaging), computation, and communication capabilities. The competing requirements for applications of these wireless sensor networks (WSN)…

  15. The Use of Mobile-Wireless Technology for Education.

    ERIC Educational Resources Information Center

    Altalib, Hasan

    This paper focuses on the use of mobile-wireless technology for education. The first section is an introduction which provides a definition of the terms. The second section discusses implementation of mobile-wireless technology in schools, providing examples from Latrobe Junior High School, where wireless laptops were issued to students and River…

  16. Wireless Local Area Networks: The Next Evolutionary Step.

    ERIC Educational Resources Information Center

    Wodarz, Nan

    2001-01-01

    The Institute of Electrical and Electronics Engineers recently approved a high-speed wireless standard that enables devices from different manufacturers to communicate through a common backbone, making wireless local area networks more feasible in schools. Schools can now use wireless access points and network cards to provide flexible…

  17. Wireless Site-specific Irrigation - The Future of Intelligent Agriculture

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A wireless site-specific irrigation system was developed with a distributed wireless sensor network. The system allows growers to remotely access field conditions and an irrigation operation at the home or office via wireless radio communication, directing individual sprinklers on how much water to ...

  18. Wireless sensor network for monitoring soil moisture and weather conditions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A wireless sensor network (WSN) was developed and deployed in three fields to monitor soil water status and collect weather data for irrigation scheduling. The WSN consists of soil-water sensors, weather sensors, wireless data loggers, and a wireless modem. Soil-water sensors were installed at three...

  19. 47 CFR 74.870 - Wireless video assist devices.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 4 2011-10-01 2011-10-01 false Wireless video assist devices. 74.870 Section... Stations § 74.870 Wireless video assist devices. Television broadcast auxiliary licensees and motion picture and television producers, as defined in § 74.801 may operate wireless video assist devices on...

  20. Using Wireless Devices to Enhance Reference and Information Services

    ERIC Educational Resources Information Center

    Forsyth, Ellen

    2006-01-01

    A growing number of libraries have installed wireless data connections as a way of providing access to the Internet for members of the public. Some libraries have used their wireless networks to enable staff to use wireless devices to increase their mobility, effectiveness and responsiveness to client need particularly in providing reference and…