WorldWideScience

Sample records for network overlay geolocation

  1. Overlay networks toward information networking

    CERN Document Server

    Tarkoma, Sasu

    2010-01-01

    With their ability to solve problems in massive information distribution and processing, while keeping scaling costs low, overlay systems represent a rapidly growing area of R&D with important implications for the evolution of Internet architecture. Inspired by the author's articles on content based routing, Overlay Networks: Toward Information Networking provides a complete introduction to overlay networks. Examining what they are and what kind of structures they require, the text covers the key structures, protocols, and algorithms used in overlay networks. It reviews the current state of th

  2. Distributed Semantic Overlay Networks

    Science.gov (United States)

    Doulkeridis, Christos; Vlachou, Akrivi; Nørvåg, Kjetil; Vazirgiannis, Michalis

    Semantic Overlay Networks (SONs) have been recently proposed as a way to organize content in peer-to-peer (P2P) networks. The main objective is to discover peers with similar content and then form thematically focused peer groups. Efficient content retrieval can be performed by having queries selectively forwarded only to relevant groups of peers to the query. As a result, less peers need to be contacted, in order to answer a query. In this context, the challenge is to generate SONs in a decentralized and distributed manner, as the centralized assembly of global information is not feasible. Different approaches for exploiting the generated SONs for content retrieval have been proposed in the literature, which are examined in this chapter, with a particular focus on SON interconnections for efficient search. Several applications, such as P2P document and image retrieval, can be deployed over generated SONs, motivating the need for distributed and truly scalable SON creation. Therefore, recently several research papers focus on SONs as stated in our comprehensive overview of related work in the field of semantic overlay networks. A classification of existing algorithms according to a set of qualitative criteria is also provided. In spite of the rich existing work in the field of SONs, several challenges have not been efficiently addressed yet, therefore, future promising research directions are pointed out and discussed at the end of this chapter.

  3. MIPv6 Experimental Evaluation using Overlay Networks

    OpenAIRE

    Soto, Ignacio; Vidales, Pablo; Carlos J. Bernardos; Cottingham, David; Baliosian, Javier; Crowcroft, Jon

    2007-01-01

    The commercial deployment of Mobile IPv6 has been hastened by the concepts of Integrated Wireless Networks and Overlay Networks, which are present in the notion of the forthcoming generation of wireless communications. Individual wireless access networks show limitations that can be overcome through the integration of different technologies into a single unified platform (i.e., 4G systems). This paper summarises practical experiments performed to evaluate the impact of inter-ne...

  4. Enhanced Precision Geolocation in 4G Wireless Networks

    Science.gov (United States)

    2013-03-01

    mobile user location for wideband CDMA cellular systems,” IEEE Transactions on Wireless Communications, vol. 1, no. 3, pp. 439–447, Jul. 2002. [12...errors. 14. SUBJECT TERMS geolocation, algorithms, 4G mobile communication, optimization, WiMAX, Wireless networks 15. NUMBER OF PAGES 251 16. PRICE... mobile subscriber position as the intersection of three range circles. . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Figure 3. The case of

  5. Capacity of Intelligent Underlay and Overlay Network

    DEFF Research Database (Denmark)

    Ling, Yim; Elling, Jan; Nielsen, Thomas Toftegaard

    1996-01-01

    This paper suggests a method of dimensioning the cell configuration of radio sites in a cellular network using the intelligent overlay and underlay (IOU) technique. The traffic capacity has been analysed by means of a teletraffic model, which is developed based on the classical theory of overflow...... traffic. The formulas of the model have been implemented with the use of MatLab. To verify the model, measurement methods have been developed to collect the teletraffic information in a real-live GSM network. The measured data indicates that the teletraffic model describes the capacity with high accuracy...... and therefore can be used to dimension the network. The model shows that the increase of capacity for a GSM network with 34 frequencies is about 30%. Further capacity enhancement can be achieved by intelligent frequency planning method which is currently being developed...

  6. Community overlays upon real-world complex networks

    NARCIS (Netherlands)

    Ge, X.; Wang, H.

    2012-01-01

    Many networks are characterized by the presence of communities, densely intra-connected groups with sparser inter-connections between groups. We propose a community overlay network representation to capture large-scale properties of communities. A community overlay Go can be constructed upon a

  7. Distributed geolocation algorithm in mobile ad hoc networks using received signal strength differences

    Science.gov (United States)

    Guo, Shanzeng; Tang, Helen

    2012-05-01

    Future military wireless communication in a battlefield will be mobile ad hoc in nature. The ability to geolocate and track both friendly forces and enemies is very important in military command and control operations. However, current mobile ad hoc networks (MANET) have no capabilities to geolocate radio emitters that belong to enemy mobile ad hoc networks. This paper presents a distributed geolocation algorithm using received signal strength differences to geolocate enemy radio emitters by leveraging friendly force MANET infrastructure, and proposes a communication protocol for radio emitter geolocation applications. An enemy's radio emitter signal is detected, and its signal strength is measured by the nodes in a friendly mobile ad hoc network. The identity of the enemy radio emitter is extracted from the decoded message header of the medium access control layer. By correlating and associating the enemy's radio emitter identity with its received signal strength, the enemy radio emitter is identified. The enemy's radio emitter identity and its received signal strength are distributed and shared among friendly mobile ad hoc nodes. Using received signal strength differences, a master friendly node can calculate the enemy's radio emitter geolocation, and build a recognized MANET picture (RMP). This MANET picture is then distributed to all friendly nodes for effective command and control operations. An advantage of this method is that mobile ad hoc nodes do not need special RF antennas to geolocate the enemy radio emitter as conventional electronic warfare techniques do. MATLAB-based simulations are presented to evaluate the accuracy and reliability of the proposed distributed geolocation algorithm under different MANET placements.

  8. On-demand Overlay Networks for Large Scientific Data Transfers

    Energy Technology Data Exchange (ETDEWEB)

    Ramakrishnan, Lavanya [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Guok, Chin [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Jackson, Keith [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Kissel, Ezra [Univ. of Delaware, Newark, DE (United States); Swany, D. Martin [Univ. of Delaware, Newark, DE (United States); Agarwal, Deborah [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2009-10-12

    Large scale scientific data transfers are central to scientific processes. Data from large experimental facilities have to be moved to local institutions for analysis or often data needs to be moved between local clusters and large supercomputing centers. In this paper, we propose and evaluate a network overlay architecture to enable highthroughput, on-demand, coordinated data transfers over wide-area networks. Our work leverages Phoebus and On-demand Secure Circuits and AdvanceReservation System (OSCARS) to provide high performance wide-area network connections. OSCARS enables dynamic provisioning of network paths with guaranteed bandwidth and Phoebus enables the coordination and effective utilization of the OSCARS network paths. Our evaluation shows that this approach leads to improved end-to-end data transfer throughput with minimal overheads. The achievedthroughput using our overlay was limited only by the ability of the end hosts to sink the data.

  9. Using overlay network architectures for scalable video distribution

    Science.gov (United States)

    Patrikakis, Charalampos Z.; Despotopoulos, Yannis; Fafali, Paraskevi; Cha, Jihun; Kim, Kyuheon

    2004-11-01

    Within the last years, the enormous growth of Internet based communication as well as the rapid increase of available processing power has lead to the widespread use of multimedia streaming as a means to convey information. This work aims at providing an open architecture designed to support scalable streaming to a large number of clients using application layer multicast. The architecture is based on media relay nodes that can be deployed transparently to any existing media distribution scheme, which can support media streamed using the RTP and RTSP protocols. The architecture is based on overlay networks at application level, featuring rate adaptation mechanisms for responding to network congestion.

  10. Lightweight storage and overlay networks for fault tolerance.

    Energy Technology Data Exchange (ETDEWEB)

    Oldfield, Ron A.

    2010-01-01

    The next generation of capability-class, massively parallel processing (MPP) systems is expected to have hundreds of thousands to millions of processors, In such environments, it is critical to have fault-tolerance mechanisms, including checkpoint/restart, that scale with the size of applications and the percentage of the system on which the applications execute. For application-driven, periodic checkpoint operations, the state-of-the-art does not provide a scalable solution. For example, on today's massive-scale systems that execute applications which consume most of the memory of the employed compute nodes, checkpoint operations generate I/O that consumes nearly 80% of the total I/O usage. Motivated by this observation, this project aims to improve I/O performance for application-directed checkpoints through the use of lightweight storage architectures and overlay networks. Lightweight storage provide direct access to underlying storage devices. Overlay networks provide caching and processing capabilities in the compute-node fabric. The combination has potential to signifcantly reduce I/O overhead for large-scale applications. This report describes our combined efforts to model and understand overheads for application-directed checkpoints, as well as implementation and performance analysis of a checkpoint service that uses available compute nodes as a network cache for checkpoint operations.

  11. On cooperative and efficient overlay network evolution based on a group selection pattern.

    Science.gov (United States)

    Nakao, Akihiro; Wang, Yufeng

    2010-04-01

    In overlay networks, the interplay between network structure and dynamics remains largely unexplored. In this paper, we study dynamic coevolution between individual rational strategies (cooperative or defect) and the overlay network structure, that is, the interaction between peer's local rational behaviors and the emergence of the whole network structure. We propose an evolutionary game theory (EGT)-based overlay topology evolution scheme to drive a given overlay into the small-world structure (high global network efficiency and average clustering coefficient). Our contributions are the following threefold: From the viewpoint of peers' local interactions, we explicitly consider the peer's rational behavior and introduce a link-formation game to characterize the social dilemma of forming links in an overlay network. Furthermore, in the evolutionary link-formation phase, we adopt a simple economic process: Each peer keeps one link to a cooperative neighbor in its neighborhood, which can slightly speed up the convergence of cooperation and increase network efficiency; from the viewpoint of the whole network structure, our simulation results show that the EGT-based scheme can drive an arbitrary overlay network into a fully cooperative and efficient small-world structure. Moreover, we compare our scheme with a search-based economic model of network formation and illustrate that our scheme can achieve the experimental and analytical results in the latter model. In addition, we also graphically illustrate the final overlay network structure; finally, based on the group selection model and evolutionary set theory, we theoretically obtain the approximate threshold of cost and draw the conclusion that the small value of the average degree and the large number of the total peers in an overlay network facilitate the evolution of cooperation.

  12. Twitter User Geolocation Using a Unified Text and Network Prediction Model

    OpenAIRE

    Rahimi, Afshin; Cohn, Trevor; Baldwin, Timothy

    2015-01-01

    We propose a label propagation approach to geolocation prediction based on Modified Adsorption, with two enhancements:(1) the removal of "celebrity" nodes to increase location homophily and boost tractability, and (2) he incorporation of text-based geolocation priors for test users. Experiments over three Twitter benchmark datasets achieve state-of-the-art results, and demonstrate the effectiveness of the enhancements.

  13. A Measurement Study of the Structured Overlay Network in P2P File-Sharing Systems

    Directory of Open Access Journals (Sweden)

    Mo Zhou

    2007-08-01

    Full Text Available The architecture of P2P file-sharing applications has been developing to meet the needs of large scale demands. The structured overlay network, also known as DHT, has been used in these applications to improve the scalability, and robustness of the system, and to make it free from single-point failure. We believe that the measurement study of the overlay network used in the real file-sharing P2P systems can provide guidance for the designing of such systems, and improve the performance of the system. In this paper, we perform the measurement in two different aspects. First, a modified client is designed to provide view to the overlay network from a single-user vision. Second, the instances of crawler programs deployed in many nodes managed to crawl the user information of the overlay network as much as possible. We also find a vulnerability in the overlay network, combined with the character of the DNS service, a more serious DDoS attack can be launched.

  14. Distributed evaluation of continuous equi-join queries over large structured overlay networks

    NARCIS (Netherlands)

    S. Idreos (Stratos); C. Tryfonopoulos; M. Koubarakis (Manolis)

    2006-01-01

    textabstractWe study the problem of continuous relational query processing in Internet-scale overlay networks realized by distributed hash tables. We concentrate on the case of continuous two-way equi-join queries. Joins are hard to evaluate in a distributed continuous query environment because data

  15. A Secure and Stable Multicast Overlay Network with Load Balancing for Scalable IPTV Services

    Directory of Open Access Journals (Sweden)

    Tsao-Ta Wei

    2012-01-01

    Full Text Available The emerging multimedia Internet application IPTV over P2P network preserves significant advantages in scalability. IPTV media content delivered in P2P networks over public Internet still preserves the issues of privacy and intellectual property rights. In this paper, we use SIP protocol to construct a secure application-layer multicast overlay network for IPTV, called SIPTVMON. SIPTVMON can secure all the IPTV media delivery paths against eavesdroppers via elliptic-curve Diffie-Hellman (ECDH key exchange on SIP signaling and AES encryption. Its load-balancing overlay tree is also optimized from peer heterogeneity and churn of peer joining and leaving to minimize both service degradation and latency. The performance results from large-scale simulations and experiments on different optimization criteria demonstrate SIPTVMON's cost effectiveness in quality of privacy protection, stability from user churn, and good perceptual quality of objective PSNR values for scalable IPTV services over Internet.

  16. Microeconomics-based resource allocation in overlay networks by using non-strategic behavior modeling

    Science.gov (United States)

    Analoui, Morteza; Rezvani, Mohammad Hossein

    2011-01-01

    Behavior modeling has recently been investigated for designing self-organizing mechanisms in the context of communication networks in order to exploit the natural selfishness of the users with the goal of maximizing the overall utility. In strategic behavior modeling, the users of the network are assumed to be game players who seek to maximize their utility with taking into account the decisions that the other players might make. The essential difference between the aforementioned researches and this work is that it incorporates the non-strategic decisions in order to design the mechanism for the overlay network. In this solution concept, the decisions that a peer might make does not affect the actions of the other peers at all. The theory of consumer-firm developed in microeconomics is a model of the non-strategic behavior that we have adopted in our research. Based on it, we have presented distributed algorithms for peers' "joining" and "leaving" operations. We have modeled the overlay network as a competitive economy in which the content provided by an origin server can be viewed as commodity and the origin server and the peers who multicast the content to their downside are considered as the firms. On the other hand, due to the dual role of the peers in the overlay network, they can be considered as the consumers as well. On joining to the overlay economy, each peer is provided with an income and tries to get hold of the service regardless to the behavior of the other peers. We have designed the scalable algorithms in such a way that the existence of equilibrium price (known as Walrasian equilibrium price) is guaranteed.

  17. A Prediction System Using a P2P Overlay Network for a Bus Arrival System

    Directory of Open Access Journals (Sweden)

    Ssu-Hsuan Lu

    2014-01-01

    Full Text Available Along with the evolution of times and the surge of metropolitan populations, government agencies often promote the construction of public transport. Unlike rail transportation or rapid transit systems, it is often difficult to estimate the vehicle arrival times at each station in a bus transportation system due to metropolitan transportation congestion. Traffic status is often monitored using wireless sensor networks (WSNs. However, WSNs are always separated from one another spatially. Recent studies have considered the connection of multiple sensor networks. This study considers a combination view of peer-to-peer (P2P overlay networks and WSN architecture to predict bus arrival times. Each bus station, which is also a P2P overlay peer, is connected in a P2P overlay network. A sensor installed in each bus can receive data via peers to obtain the moving speed of a bus. Then, each peer can exchange its data to predict bus arrival times at bus stations. This method can considerably increase the accuracy with which bus arrival times can be predicted and can provide traffic status with high precision. Furthermore, these data can also be used to plan new bus routes according to the information gathered.

  18. PLATON: Peer-to-Peer load adjusting tree overlay networks

    NARCIS (Netherlands)

    Lymberopoulos, L.; Pittaras, C.; Grammatikou, M.; Papavassiliou, S.; Maglaris, V.

    2011-01-01

    Peer-to-Peer systems supporting multi attribute and range queries use a number of techniques to partition the multi dimensional data space among participating peers. Load-balancing of data accross peer partitions is necessary in order to avoid the presence of network hotspots which may cause

  19. The Effects of a Dynamic Spectrum Access Overlay in LTE-Advanced Networks

    Energy Technology Data Exchange (ETDEWEB)

    Juan D. Deaton; Ryan E. lrwin; Luiz A. DaSilva

    2011-05-01

    As early as 2014, wireless network operators spectral capacity will be overwhelmed by a data tsunami brought on by new devices and applications. To augment spectral capacity, operators could deploy a Dynamic Spectrum Access (DSA) overlay. In the light of the many planned Long Term Evolution (LTE) network deployments, the affects of a DSA overlay have not been fully considered into the existing LTE standards. Coalescing many different aspects of DSA, this paper develops the Spectrum Accountability (SA) framework. The SA framework defines specific network element functionality, protocol interfaces, and signaling flow diagrams for LTE to support service requests and enforce rights of responsibilities of primary and secondary users, respectively. We also include a network simulation to quantify the benefits of using DSA channels to augment capacity. Based on our simulation we show that, network operators can benefit up to %40 increase in operating capacity when sharing DSA bands to augment spectral capacity. With our framework, this paper could serve as an guide in developing future LTE network standards that include DSA.

  20. Secret Forwarding of Events over Distributed Publish/Subscribe Overlay Network.

    Directory of Open Access Journals (Sweden)

    Young Yoon

    Full Text Available Publish/subscribe is a communication paradigm where loosely-coupled clients communicate in an asynchronous fashion. Publish/subscribe supports the flexible development of large-scale, event-driven and ubiquitous systems. Publish/subscribe is prevalent in a number of application domains such as social networking, distributed business processes and real-time mission-critical systems. Many publish/subscribe applications are sensitive to message loss and violation of privacy. To overcome such issues, we propose a novel method of using secret sharing and replication techniques. This is to reliably and confidentially deliver decryption keys along with encrypted publications even under the presence of several Byzantine brokers across publish/subscribe overlay networks. We also propose a framework for dynamically and strategically allocating broker replicas based on flexibly definable criteria for reliability and performance. Moreover, a thorough evaluation is done through a case study on social networks using the real trace of interactions among Facebook users.

  1. Optimización multiobjetivo para enrutamiento multicast en overlay networks utilizando algoritmos evolutivos Multiobjective Optimization for Multicast Routing in Overlay Networks using Evolutionary Algorithms

    Directory of Open Access Journals (Sweden)

    Juan Carlos Montoya M.

    2008-06-01

    Full Text Available Multicast juega un papel muy importante para soportar una nueva generación de aplicaciones. En la actualidad y por diferentes razones, técnicas y no técnicas, multicast IP no ha sido totalmente adoptado en Internet. Durante los últimos a˜nos, un área de investigación activa es la de implementar este tipo de tráfico desde la perspectiva del nivel de aplicación, donde la funcionalidad de multicast no es responsabilidad de los enrutadores sino de los hosts, a lo que se le conoce como Multicast Overlay Network (MON. En este artículo se plantea el enrutamiento en MON como un problema de Optimización Multiobjetivo (MOP donde se optimizan dos funciones: 1 el retardo total extremo a extremo del árbol multicast, y 2 la máxima utilización de los enlaces. La optimización simultánea de estas dos funciones es un problema NP completo y para resolverlo se propone utilizar Algoritmos Evolutivos Multiobjetivos (MOEA, específicamente NSGAIMulticast plays an important role in supporting a new generation of applications. At present and for different reasons, technical and non–technical, multicast IP hasn’t yet been totally adopted for Internet. During recent years, an active area of research is that of implementing this kind of traffic in the application layer where the multicast functionality isn´t a responsibility of the routers but that of the hosts, which we know as Multicast Overlay Networks (MON. In this article, routing in an MON is put forward as a multiobjective optimization problem (MOP where two functions are optimized: 1 the total end to end delay of the multicast tree and 2 the maximum link utilization. The simultaneous optimization of these two functions is an NP–Complete problem and to solve this we suggest using Multiobjective Evolutionary Algorithms (MOEA, specifically NSGA–II.

  2. Modeling and simulation of adaptive Neuro-fuzzy based intelligent system for predictive stabilization in structured overlay networks

    Directory of Open Access Journals (Sweden)

    Ramanpreet Kaur

    2017-02-01

    Full Text Available Intelligent prediction of neighboring node (k well defined neighbors as specified by the dht protocol dynamism is helpful to improve the resilience and can reduce the overhead associated with topology maintenance of structured overlay networks. The dynamic behavior of overlay nodes depends on many factors such as underlying user’s online behavior, geographical position, time of the day, day of the week etc. as reported in many applications. We can exploit these characteristics for efficient maintenance of structured overlay networks by implementing an intelligent predictive framework for setting stabilization parameters appropriately. Considering the fact that human driven behavior usually goes beyond intermittent availability patterns, we use a hybrid Neuro-fuzzy based predictor to enhance the accuracy of the predictions. In this paper, we discuss our predictive stabilization approach, implement Neuro-fuzzy based prediction in MATLAB simulation and apply this predictive stabilization model in a chord based overlay network using OverSim as a simulation tool. The MATLAB simulation results present that the behavior of neighboring nodes is predictable to a large extent as indicated by the very small RMSE. The OverSim based simulation results also observe significant improvements in the performance of chord based overlay network in terms of lookup success ratio, lookup hop count and maintenance overhead as compared to periodic stabilization approach.

  3. Efficient content distribution for peer-to-peer overlays on mobile ad hoc networks

    Directory of Open Access Journals (Sweden)

    Afzal Mawji

    2011-07-01

    Full Text Available Peer-to-peer (P2P networks existing on a MANET are a natural evolution since both are decentralized and have dynamic topologies. As MANETs grow in use due to the increasing popularity of wireless mesh and 4G networks, it is expected that P2P applications will remain as a popular means of obtaining files. Network coding has been shown as an efficient means of sharing large files in a P2P network. With network coding, all file blocks have the same relative importance. This paper presents an efficient content distribution scheme that uses network coding to share large files in a P2P overlay running on a MANET. Peers request file blocks from multiple server nodes and servers multicast blocks to multiple receivers, providing efficient multipoint-to-multipoint communication. Simulation results show that compared to other common download techniques, the proposed scheme performs very well, having lower download time and energy consumption. Also, more peers participate in uploading the file, resulting in greater fairness.

  4. An efficient mechanism for dynamic multicast traffic grooming in overlay IP/MPLS over WDM networks

    Science.gov (United States)

    Yu, Xiaojun; Xiao, Gaoxi; Cheng, Tee Hiang

    2014-08-01

    This paper proposes an efficient overlay multicast provisioning (OMP) mechanism for dynamic multicast traffic grooming in overlay IP/MPLS over WDM networks. To facilitate request provisioning, OMP jointly utilizes a data learning (DL) scheme on the IP/MPLS layer for logical link cost estimation, and a lightpath fragmentation (LPF) based method on the WDM layer for improving resource sharing in grooming process. Extensive simulations are carried out to evaluate the performance of OMP mechanism under different traffic loads, with either limited or unlimited port resources. Simulation results demonstrate that OMP significantly outperforms the existing methods. To evaluate the respective influences of the DL scheme and the LPF method on OMP performance, provisioning mechanisms only utilizing either the IP/MPLS layer DL scheme or the WDM layer LPF method are also devised. Comparison results show that both DL and LPF methods help improve OMP blocking performance, and contribution from the DL scheme is more significant when the fixed routing and first-fit wavelength assignment (RWA) strategy is adopted on the WDM layer. Effects of a few other factors, including definition of connection cost to be reported by the WDM layer to the IP/MPLS layer and WDM-layer routing method, on OMP performance are also evaluated.

  5. Analysis And Augmentation Of Timing Advance Based Geolocation In Lte Cellular Networks

    Science.gov (United States)

    2016-12-01

    of Sight ODTOA Observed Time-Difference-of-Arrival OFDM Orthogonal Frequency-Division Multiplexing OFDMA Orthogonal Frequency-Division Multiple ...Access PCell Primary Serving Cell PDCCH Physical Downlink Control Channel PDCP Packet Data Convergence Protocol PDF Probability Density Function PMF...primarily responsible for managing user mobility in various time division multiple access-based cellular networks. Specifically, this is accomplished via

  6. Self-Adapting Routing Overlay Network for Frequently Changing Application Traffic in Content-Based Publish/Subscribe System

    Directory of Open Access Journals (Sweden)

    Meng Chi

    2014-01-01

    Full Text Available In the large-scale distributed simulation area, the topology of the overlay network cannot always rapidly adapt to frequently changing application traffic to reduce the overall traffic cost. In this paper, we propose a self-adapting routing strategy for frequently changing application traffic in content-based publish/subscribe system. The strategy firstly trains the traffic information and then uses this training information to predict the application traffic in the future. Finally, the strategy reconfigures the topology of the overlay network based on this predicting information to reduce the overall traffic cost. A predicting path is also introduced in this paper to reduce the reconfiguration numbers in the process of the reconfigurations. Compared to other strategies, the experimental results show that the strategy proposed in this paper could reduce the overall traffic cost of the publish/subscribe system in less reconfigurations.

  7. IP Infrastructure Geolocation

    Science.gov (United States)

    2015-03-01

    Provider ITDK Internet Topology Data Kit LIS Location Information Server NPS Naval Postgraduate School PC Personal Computer POP Point of Presence PTR...Information Server (LIS) [6]. Before IETF protocols are enhanced with geolocation features, the location of an Internet device has to be deduced by other...environments may rely on WPS for geolocation. WPS de- vices geolocate their location by querying public WiFi location databases with the Ba- sic Service

  8. Geolocation by light

    DEFF Research Database (Denmark)

    Lisovski, Simeon; Hewson, Chris M.; Klaassen, Raymond H. G.

    2012-01-01

    1. Geolocation by light allows for tracking animal movements, based on measurements of light intensity over time by a data-logging device (‘geolocator’). Recent developments of ultra-light devices (... factors that influence light intensities. We demonstrated their effect on the measurement of day /night length, time of solar midnight /noon and the resulting position estimates using light measurements from stationary geolocators at known places and from geolocators mounted on birds. Furthermore, we...

  9. HTML5 Geolocation

    CERN Document Server

    Holdener, Anthony

    2011-01-01

    Truly revolutionary: now you can write geolocation applications directly in the browser, rather than develop native apps for particular devices. This concise book demonstrates the W3C Geolocation API in action, with code and examples to help you build HTML5 apps using the "write once, deploy everywhere" model. Along the way, you get a crash course in geolocation, browser support, and ways to integrate the API with common geo tools like Google Maps. Learn how geo information is gathered from different sources, depending on the deviceDiscover how coordinate systems work, including geodetic syst

  10. TinCan: User-Defined P2P Virtual Network Overlays for Ad-hoc Collaboration

    Directory of Open Access Journals (Sweden)

    Pierre St Juste

    2014-10-01

    Full Text Available Virtual private networking (VPN has become an increasingly important component of a collaboration environment because it ensures private, authenticated communication among participants, using existing collaboration tools, where users are distributed across multiple institutions and can be mobile. The majority of current VPN solutions are based on a centralized VPN model, where all IP traffic is tunneled through a VPN gateway. Nonetheless, there are several use case scenarios that require a model where end-to-end VPN links are tunneled upon existing Internet infrastructure in a peer-to-peer (P2P fashion, removing the bottleneck of a centralized VPN gateway. We propose a novel virtual network — TinCan — based on peerto-peer private network tunnels. It reuses existing standards and implementations of services for discovery notification (XMPP, reflection (STUN and relaying (TURN, facilitating configuration. In this approach, trust relationships maintained by centralized (or federated services are automatically mapped to TinCan links. In one use scenario, TinCan allows unstructured P2P overlays connecting trusted end-user devices — while only requiring VPN software on user devices and leveraging online social network (OSN infrastructure already widely deployed. This paper describes the architecture and design of TinCan and presents an experimental evaluation of a prototype supporting Windows, Linux, and Android mobile devices. Results quantify the overhead introduced by the network virtualization layer, and the resource requirements imposed on services needed to bootstrap TinCan links.

  11. Aggregated journal–journal citation relations in scopus and web of science matched and compared in terms of networks, maps, and interactive overlays

    NARCIS (Netherlands)

    Leydesdorff, L.; de Moya-Anegón, F.; de Nooy, W.

    We compare the network of aggregated journal–journal citation relations provided by the Journal Citation Reports (JCR) 2012 of the Science Citation Index (SCI) and Social Sciences Citation Index (SSCI) with similar data based on Scopus 2012. First, global and overlay maps were developed for the 2

  12. Geolocation Technologies Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Magnoli, D E

    2003-06-02

    This paper is the final report for LL998 In Situ Sensing Subtask 7 (Geo-location) undertaken for NNSA NA-22 enabling technologies R&D for Counterproliferation Detection. A few state-of-the-art resolution parameters are presented for accelerometers, indoor and outdoor GPS (Global Positioning Satellite) systems, and INSs (Inertial Navigation Systems). New technologies are described, including one which has demonstrated the ability to track within a building to a resolution of under a foot.

  13. Scheduled MAC in Beacon Overlay Networks for Underwater Localization and Time-Synchronization

    NARCIS (Netherlands)

    van Kleunen, W.A.P.; Meratnia, Nirvana; Havinga, Paul J.M.

    2011-01-01

    In this article we introduce a MAC protocol designed for underwater localization and time-synchronisation. The MAC protocol assumes a network of static reference nodes and allows blind nodes to be localized by listening-only to the beacon messages. Such a system is known to be very scalable. We show

  14. On the Capacity of a GSM Frequency Hopping network with Intelligent Underlayer-Overlayer

    DEFF Research Database (Denmark)

    Nielsen, Thomas Toftegaard; Wigard, Jeroen; Mogensen, Preben Elgaard

    1997-01-01

    This paper describes a method to increase the capacity of a digital cellular network, like GSM, without having to increase the number of available frequencies or base stations. The idea is to split the frequency spectrum into two bands. One consisting of frequencies that can only be used when...

  15. Streaming Multimedia via Overlay Networks using Wi-Fi Peer-to-Peer Connections

    DEFF Research Database (Denmark)

    Poderys, Justas; Soler, José

    2017-01-01

    Short range ad-hoc wireless networks can be used to deliver streaming multimedia for information, entertainment and advertisement purposes. To enable short-range communication between various devices, the Wi-Fi Alliance proposed an extension to the IEEE802.11 Wi-Fi standard called Wi-Fi Peer-to-P....... The evaluation is done by streaming Live and Video-on-Demand multimedia among the different size user groups and observing the streaming multimedia Quality-of-Service parameters....

  16. A Traffic Prediction Model for Self-Adapting Routing Overlay Network in Publish/Subscribe System

    Directory of Open Access Journals (Sweden)

    Meng Chi

    2017-01-01

    Full Text Available In large-scale location-based service, an ideal situation is that self-adapting routing strategies use future traffic data as input to generate a topology which could adapt to the changing traffic well. In the paper, we propose a traffic prediction model for the broker in publish/subscribe system, which can predict the traffic of the link in future by neural network. We first introduced our traffic prediction model and then described the model integration. Finally, the experimental results show that our traffic prediction model could predict the traffic of link well.

  17. Neighbor Selection in Peer-to-Peer Overlay Networks: A Swarm Intelligence Approach

    Science.gov (United States)

    Liu, Hongbo; Abraham, Ajith; Badr, Youakim

    Peer-to-peer (P2P) topology has a significant influence on the performance, search efficiency and functionality, and scalability of the application. In this chapter, we investigate a multi-swarm approach to the problem of neighbor selection in P2P networks. Particle swarm share some common characteristics with P2P in the dynamic socially environment. Each particle encodes the upper half of the peer-connection matrix through the undirected graph, which reduces the search space dimension. The portion of the adjustment to the velocity influenced by the individual’s cognition, the group cognition from multi-swarms, and the social cognition from the whole swarm, makes an important influence on the particles’ ergodic and synergetic performance. We also attempt to theoretically prove that the multi-swarm optimization algorithm converges with a probability of 1 towards the global optima. The performance of our approach is evaluated and compared with other two different algorithms. The results indicate that it usually required shorter time to obtain better results than the other considered methods, specially for large scale problems.

  18. Using a geolocation social networking application to calculate the population density of sex-seeking gay men for research and prevention services.

    Science.gov (United States)

    Delaney, Kevin P; Kramer, Michael R; Waller, Lance A; Flanders, W Dana; Sullivan, Patrick S

    2014-11-18

    In the United States, human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS) continues to have a heavy impact on men who have sex with men (MSM). Among MSM, black men under the age of 30 are at the most risk for being diagnosed with HIV. The US National HIV/AIDS strategy recommends intensifying efforts in communities that are most heavily impacted; to do so requires new methods for identifying and targeting prevention resources to young MSM, especially young MSM of color. We piloted a methodology for using the geolocation features of social and sexual networking applications as a novel approach to calculating the local population density of sex-seeking MSM and to use self-reported age and race from profile postings to highlight areas with a high density of minority and young minority MSM in Atlanta, Georgia. We collected data from a geographically systematic sample of points in Atlanta. We used a sexual network mobile phone app and collected application profile data, including age, race, and distance from each point, for either the 50 closest users or for all users within a 2-mile radius of sampled points. From these data, we developed estimates of the spatial density of application users in the entire city, stratified by race. We then compared the ratios and differences between the spatial densities of black and white users and developed an indicator of areas with the highest density of users of each race. We collected data from 2666 profiles at 79 sampled points covering 883 square miles; overlapping circles of data included the entire 132.4 square miles in Atlanta. Of the 2666 men whose profiles were observed, 1563 (58.63%) were white, 810 (30.38%) were black, 146 (5.48%) were another race, and 147 (5.51%) did not report a race in their profile. The mean age was 31.5 years, with 591 (22.17%) between the ages of 18-25, and 496 (18.60%) between the ages of 26-30. The mean spatial density of observed profiles was 33 per square mile, but the

  19. Internet Geo-Location

    Science.gov (United States)

    2017-12-01

    Latency Inflation in AT&T’s Network ........................................................................................... 25 6.2 Comparison of...associated with latitude-longitude coordinates, we ignore error distances below 10 km. .... 16 Figure 14: Fiber Conduits in USA ...24 Figure 21: Inflation in AT&T’s network

  20. Camera Geolocation From Mountain Images

    Science.gov (United States)

    2015-09-17

    be reliably extracted from query images. However, in real-life scenarios the skyline in a query image may be blurred or invisible , due to occlusions...extracted from multiple mountain ridges is critical to reliably geolocating challenging real-world query images with blurred or invisible mountain skylines...Buddemeier, A. Bissacco, F. Brucher, T. Chua, H. Neven, and J. Yagnik, “Tour the world: building a web -scale landmark recognition engine,” in Proc. of

  1. Phase difference of arrival geolocation

    Science.gov (United States)

    Mason, John J.; Romero, Louis (

    2017-05-16

    Geolocation is performed by receiving, at a plurality of non-earthbound platforms each moving in a known manner within a spatial coordinate system, a radio frequency (RF) signal transmitted from a transmitter at an unknown location on earth within the spatial coordinate system. For each of the platforms, a phase change of the received frequency carrier is measured over the same duration of time. The measured phase changes are combined to determine the transmitter location.

  2. Instant HTML5 geolocation how-to

    CERN Document Server

    Werdmuller, Ben

    2013-01-01

    Filled with practical, step-by-step instructions and clear explanations for the most important and useful tasks. The book will take a how-to approach, focusing on recipes that demonstrate geolocation in HTML5.This book is for web developers who want to incorporate geolocation technology into their applications. Previous knowledge about geolocation software or standards is not required. However, this book assumes a general understanding of web technologies, and both Javascript and jQuery in particular.

  3. Improving concrete overlay construction.

    Science.gov (United States)

    2010-03-01

    Several road construction projects involving concrete overlays at the state and county levels in Iowa in 2009 were studied for : construction techniques and methods. The projects that were evaluated consisted of sites in four Iowa counties: Osceola, ...

  4. RADAR PPI Scope Overlay

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — RADAR PPI Scope Overlays are used to position a RADAR image over a station at the correct resolution. The archive maintains several different RADAR resolution types,...

  5. TinCan: User-Defined P2P Virtual Network Overlays for Ad-hoc Collaboration

    OpenAIRE

    Pierre St Juste; Kyuho Jeong; Heungsik Eom; Corey Baker; Renato Figueiredo

    2014-01-01

    Virtual private networking (VPN) has become an increasingly important component of a collaboration environment because it ensures private, authenticated communication among participants, using existing collaboration tools, where users are distributed across multiple institutions and can be mobile. The majority of current VPN solutions are based on a centralized VPN model, where all IP traffic is tunneled through a VPN gateway. Nonetheless, there are several use case scenarios that require a m...

  6. Multi-level Reconfigurable Self-organization in Overlay Services

    NARCIS (Netherlands)

    Pournaras, E.

    2013-01-01

    Large-scale decentralized systems organized in overlay networks are complex to manage. Such systems integrate organizational complexity in the application-level resulting in low abstraction and modularity in their services. This thesis introduces a multi-level conceptual architecture for overlay

  7. Resilient overlay design in DWDM systems

    Directory of Open Access Journals (Sweden)

    Parodi Cecilia

    2016-01-01

    Full Text Available The goal of this work is to design a minimum cost resilient overlay network, where a data network is on top of a transport network. Two major challenges are addressed. On one hand, a single failure in the transport network causes multiple simultaneous failures; on the other, the multicommodity flow must respect integrality. An integer programming formulation is presented to design an overlay, meeting the previous constraints. We prove the problem belongs to the class NP-Hard. Then, a decomposition approach is introduced, where the problem is solved in two steps by means of relaxations of the original formulation. Experiments carried out with real-life instances, coming from the Uruguayan telecommunication operator, show that the approach is competitive with respect to previous metaheuristics, to know, Tabu-Search (TS and Variable Neighborhood Search (VNS. A modest percentage of cost-reduction is achieved in some instances, which means millionaire savings in practice.

  8. VT Data - Overlay District 20170710, South Burlington

    Data.gov (United States)

    Vermont Center for Geographic Information — Overlay data for the City of South Burlington included in this data:Flood Plain Overlay DistrictTraffic Overlay DistrictInterstate Highway Overlay DistrictData not...

  9. Electrically conductive polymer concrete overlays

    Science.gov (United States)

    Fontana, J. J.; Webster, R. P.

    1984-08-01

    The use of cathodic protection to prevent the corrosion of reinforcing steel in concrete structures has been well established. Application of a durable, skid-resistant electrically conductive polymer concrete overlay would advance the use of cathodic protection for the highway industry. Laboratory studies indicate that electrically conductive polymer concrete overlays using conductive fillers, such as calcined coke breeze, in conjunction with polyester or vinyl ester resins have resistivities of 1 to 10 ohm-cm. Both multiple-layer and premixed mortar-type overlays were made. Shear bond strengths of the conductive overlays to concrete substrates vary from 600 to 1300 psi, with the premixed overlays having bond strengths 50 to 100% higher than the multiple-layer overlays.

  10. Target noise in overlay metrology

    Science.gov (United States)

    Seligson, Joel L.; Adel, Mike E.; Izikson, Pavel; Levinski, Vladimir; Yaffe, Dan

    2004-05-01

    We have developed a method for calculating the statistical effects of spatial noise on the overlay measurement extracted from a given overlay target. The method has been applied to two kinds of overlay targets on three process layers, and the new metric, Target Noise, has been shown to correlate well to the random component of Overlay Mark Fidelity. A significant difference in terms of robustness has been observed between AIM targets and conventional Frame-in-Frame targets. The results fit well into the spatial noise hierarchy presented in this paper.

  11. IPv6 Geolocation Using Latency Constraints

    Science.gov (United States)

    2014-03-01

    Association for Internet Data Analysis CDF cumulative distribution function CIDR Classless Inter-domain Routing CBG Constraint Based Geolocation DNS...called blocks or prefixes. Blocks can span non-Classless Inter-domain Routing ( CIDR ) subsets of the address. Most ge- olocation database entries are

  12. Overlay Spectrum Sharing using Improper Gaussian Signaling

    KAUST Repository

    Amin, Osama

    2016-11-30

    Improper Gaussian signaling (IGS) scheme has been recently shown to provide performance improvements in interference limited networks as opposed to the conventional proper Gaussian signaling (PGS) scheme. In this paper, we implement the IGS scheme in overlay cognitive radio system, where the secondary transmitter broadcasts a mixture of two different signals. The first signal is selected from the PGS scheme to match the primary message transmission. On the other hand, the second signal is chosen to be from the IGS scheme in order to reduce the interference effect on the primary receiver. We then optimally design the overlay cognitive radio to maximize the secondary link achievable rate while satisfying the primary network quality of service requirements. In particular, we consider full and partial channel knowledge scenarios and derive the feasibility conditions of operating the overlay cognitive radio systems. Moreover, we derive the superiority conditions of the IGS schemes over the PGS schemes supported with closed form expressions for the corresponding power distribution and the circularity coefficient and parameters. Simulation results are provided to support our theoretical derivations.

  13. Trends in MODIS Geolocation Error Analysis

    Science.gov (United States)

    Wolfe, R. E.; Nishihama, Masahiro

    2009-01-01

    Data from the two MODIS instruments have been accurately geolocated (Earth located) to enable retrieval of global geophysical parameters. The authors describe the approach used to geolocate with sub-pixel accuracy over nine years of data from M0DIS on NASA's E0S Terra spacecraft and seven years of data from MODIS on the Aqua spacecraft. The approach uses a geometric model of the MODIS instruments, accurate navigation (orbit and attitude) data and an accurate Earth terrain model to compute the location of each MODIS pixel. The error analysis approach automatically matches MODIS imagery with a global set of over 1,000 ground control points from the finer-resolution Landsat satellite to measure static biases and trends in the MO0lS geometric model parameters. Both within orbit and yearly thermally induced cyclic variations in the pointing have been found as well as a general long-term trend.

  14. Radio Frequency Emitter Geolocation Using Cubesats

    Science.gov (United States)

    2014-03-27

    Earth, which reduces error. The solution described uses the geocentric coordinate system. TDOA for each satellite pair is defined as the time from...Principles and Applications. Springer, 2013. [5] D. J. Torrieri, “Statistical theory of passive location systems,” IEEE Transactions on Aerospace and...geolocation,” 20 August 2013, AFRL/RVSV. [30] G. W. Stewart, “Gershgorin theory for the generalized eigenvalue problem,” Mathematics of Computation, vol. 29

  15. Overlay similarity: a new overlay index for metrology tool and scanner overlay fingerprint methodology

    Science.gov (United States)

    Ke, Chih-Ming; Kao, Ching-Pin; Wang, Yu-Hsi; Hu, Jimmy; Chang, Chen-Yu; Tsai, Ya-Jung; Yen, Anthony; Lin, Burn J.

    2009-03-01

    For different CD metrologies like average CD from CD SEM and optical CD (OCD) from scatterometry, CD point-to-point R2 has been well adopted as the CD correlation index. For different overlay metrologies like image-based box-in-box overlay and scatterometry-based overlay, we propose the cosine similarity as the correlation index of overlay. The cosine similarity is a measure of similarity between two vectors of n dimensions by finding the cosine of the angle between them, often used to compare documents in text mining. It has been widely used in web and document search engines and can be used as the similarity index of overlay tool-to-tool matching and scanner tool-to-tool or day-to-day fingerprint. In this paper, we demonstrate that the cosine similarity has a very high sensitivity to the overly tool performance. We compared the similarities of three generations (A1, A2, A3) of the overlay tools of venders A and B and found that after target re-training and TIS correction on each tool A1 similarity to A3 can be improved from 0.9837 to 0.9951. Overlay point-to-point matching with A3 vs. A1 can be reduced from 4.8 to 2.1 nm. The tool precision similarities, i.e. tool self best similarity, for A1, A2, A3 and B are 0.9986, 0.9990, 0.9995, and 0.9994 respectively. From this table, we demonstrate that we can use old-generation overlay tool with suitable hardware maintenance, to match to the latest-generation overlay tool.

  16. Distributed Overlay Anycast Table using Space filling curves

    OpenAIRE

    Mykoniati, Eleni; Latif, Laurence; Landa, Raul; Yang, Ben; Clegg, Richard G.; Griffin, David; Rio, Miguel

    2013-01-01

    In this paper we present the \\emph{Distributed Overlay Anycast Table}, a structured overlay that implements application-layer anycast, allowing the discovery of the closest host that is a member of a given group. One application is in locality-aware peer-to-peer networks, where peers need to discover low-latency peers participating in the distribution of a particular file or stream. The DOAT makes use of network delay coordinates and a space filling curve to achieve locality-aware routing acr...

  17. A probabilistic algorithm to process geolocation data.

    Science.gov (United States)

    Merkel, Benjamin; Phillips, Richard A; Descamps, Sébastien; Yoccoz, Nigel G; Moe, Børge; Strøm, Hallvard

    2016-01-01

    The use of light level loggers (geolocators) to understand movements and distributions in terrestrial and marine vertebrates, particularly during the non-breeding period, has increased dramatically in recent years. However, inferring positions from light data is not straightforward, often relies on assumptions that are difficult to test, or includes an element of subjectivity. We present an intuitive framework to compute locations from twilight events collected by geolocators from different manufacturers. The procedure uses an iterative forward step selection, weighting each possible position using a set of parameters that can be specifically selected for each analysis. The approach was tested on data from two wide-ranging seabird species - black-browed albatross Thalassarche melanophris and wandering albatross Diomedea exulans - tracked at Bird Island, South Georgia, during the two most contrasting periods of the year in terms of light regimes (solstice and equinox). Using additional information on travel speed, sea surface temperature and land avoidance, our approach was considerably more accurate than the traditional threshold method (errors reduced to medians of 185 km and 145 km for solstice and equinox periods, respectively). The algorithm computes stable results with uncertainty estimates, including around the equinoxes, and does not require calibration of solar angles. Accuracy can be increased by assimilating information on travel speed and behaviour, as well as environmental data. This framework is available through the open source R package probGLS, and can be applied in a wide range of biologging studies.

  18. Exploiting Deep Matching and SAR Data for the Geo-Localization Accuracy Improvement of Optical Satellite Images

    Directory of Open Access Journals (Sweden)

    Nina Merkle

    2017-06-01

    Full Text Available Improving the geo-localization of optical satellite images is an important pre-processing step for many remote sensing tasks like monitoring by image time series or scene analysis after sudden events. These tasks require geo-referenced and precisely co-registered multi-sensor data. Images captured by the high resolution synthetic aperture radar (SAR satellite TerraSAR-X exhibit an absolute geo-location accuracy within a few decimeters. These images represent therefore a reliable source to improve the geo-location accuracy of optical images, which is in the order of tens of meters. In this paper, a deep learning-based approach for the geo-localization accuracy improvement of optical satellite images through SAR reference data is investigated. Image registration between SAR and optical images requires few, but accurate and reliable matching points. These are derived from a Siamese neural network. The network is trained using TerraSAR-X and PRISM image pairs covering greater urban areas spread over Europe, in order to learn the two-dimensional spatial shifts between optical and SAR image patches. Results confirm that accurate and reliable matching points can be generated with higher matching accuracy and precision with respect to state-of-the-art approaches.

  19. Advanced overlay analysis through design based metrology

    Science.gov (United States)

    Ji, Sunkeun; Yoo, Gyun; Jo, Gyoyeon; Kang, Hyunwoo; Park, Minwoo; Kim, Jungchan; Park, Chanha; Yang, Hyunjo; Yim, Donggyu; Maruyama, Kotaro; Park, Byungjun; Yamamoto, Masahiro

    2015-03-01

    As design rule shrink, overlay has been critical factor for semiconductor manufacturing. However, the overlay error which is determined by a conventional measurement with an overlay mark based on IBO and DBO often does not represent the physical placement error in the cell area. The mismatch may arise from the size or pitch difference between the overlay mark and the cell pattern. Pattern distortion caused by etching or CMP also can be a source of the mismatch. In 2014, we have demonstrated that method of overlay measurement in the cell area by using DBM (Design Based Metrology) tool has more accurate overlay value than conventional method by using an overlay mark. We have verified the reproducibility by measuring repeatable patterns in the cell area, and also demonstrated the reliability by comparing with CD-SEM data. We have focused overlay mismatching between overlay mark and cell area until now, further more we have concerned with the cell area having different pattern density and etch loading. There appears a phenomenon which has different overlay values on the cells with diverse patterning environment. In this paper, the overlay error was investigated from cell edge to center. For this experiment, we have verified several critical layers in DRAM by using improved(Better resolution and speed) DBM tool, NGR3520.

  20. SMEX02 Land Surface Information: Geolocation, Surface Roughness, and Photographs

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set combines various ancillary data (geolocation, surface roughness, and photographs) collected for the Iowa Soil Moisture Experiment 2002 (SMEX02) study...

  1. Sentinel-1A Product Geolocation Accuracy: Commissioning Phase Results

    Directory of Open Access Journals (Sweden)

    Adrian Schubert

    2015-07-01

    Full Text Available Sentinel-1A (S1A is an Earth observation satellite carrying a state-of-the-art Synthetic Aperture Radar (SAR imaging instrument. It was launched by the European Space Agency (ESA on 3 April 2014. With the end of the in-orbit commissioning phase having been completed at the end of September 2014, S1A data products are already consistently providing highly accurate geolocation. StripMap (SM mode products were acquired regularly and tested for geolocation accuracy and consistency during dedicated corner reflector (CR campaigns. At the completion of this phase, small geometric inconsistencies had been understood and mitigated, with the high quality of the final product geolocation estimates reflecting the mission’s success thus far. This paper describes the measurement campaign, the methods used during geolocation estimation, and presents best estimates of the product Absolute Location Error (ALE available at the beginning of S1A’s operational phase.

  2. Assessment of an air pollution monitoring network to generate urban air pollution maps using Shannon information index, fuzzy overlay, and Dempster-Shafer theory, A case study: Tehran, Iran

    Science.gov (United States)

    Pahlavani, Parham; Sheikhian, Hossein; Bigdeli, Behnaz

    2017-10-01

    Air pollution assessment is an imperative part of megacities planning and control. Hence, a new comprehensive approach for air pollution monitoring and assessment was introduced in this research. It comprises of three main sections: optimizing the existing air pollutant monitoring network, locating new stations to complete the coverage of the existing network, and finally, generating an air pollution map. In the first section, Shannon information index was used to find less informative stations to be candidate for removal. Then, a methodology was proposed to determine the areas which are not sufficiently covered by the current network. These areas are candidates for establishing new monitoring stations. The current air pollution monitoring network of Tehran was used as a case study, where the air pollution issue has been worsened due to the huge population, considerable commuters' absorption and topographic barriers. In this regard, O3, NO, NO2, NOx, CO, PM10, and PM2.5 were considered as the main pollutants of Tehran. Optimization step concluded that all the 16 active monitoring stations should be preserved. Analysis showed that about 35% of the Tehran's area is not properly covered by monitoring stations and about 30% of the area needs additional stations. The winter period in Tehran always faces the most severe air pollution in the year. Hence, to produce the air pollution map of Tehran, three-month of winter measurements of the mentioned pollutants, repeated for five years in the same period, were selected and extended to the entire area using the kriging method. Experts specified the contribution of each pollutant in overall air pollution. Experts' rankings aggregated by a fuzzy-overlay process. Resulted maps characterized the study area with crucial air pollution situation. According to the maps, more than 45% of the city area faced high pollution in the study period, while only less than 10% of the area showed low pollution. This situation confirms the need

  3. Sexual practices in geolocation between men’s: bodies, pleasures, technologies

    Directory of Open Access Journals (Sweden)

    Walter Couto

    2016-07-01

    Full Text Available Locative media, geolocation applications, as well as homosocialization web spaces are problematized so as to promote some separation from the traps of normalization and pathologization. These unfold themselves into prosthetic pleasures that take their place in the experiencing of bodies and of their multiplicity linked to technologies of (deterritorialization. We question how Psychology can think of concepts/devices towards the new sexes/genders/pleasures of digital social networks and towards the normative traps that pose themselves at the interactions of these spaces.

  4. VT Data - Scenic Overlay District 20110301, Winhall

    Data.gov (United States)

    Vermont Center for Geographic Information — Scenic Restriction overaly districts for the Town of Winhall, Vermont. Other overlay districts (Transfer of Development Rights, and Conservation & Recreational...

  5. PRICISE TARGET GEOLOCATION AND TRACKING BASED ON UAV VIDEO IMAGERY

    Directory of Open Access Journals (Sweden)

    H. R. Hosseinpoor

    2016-06-01

    Full Text Available There is an increasingly large number of applications for Unmanned Aerial Vehicles (UAVs from monitoring, mapping and target geolocation. However, most of commercial UAVs are equipped with low-cost navigation sensors such as C/A code GPS and a low-cost IMU on board, allowing a positioning accuracy of 5 to 10 meters. This low accuracy cannot be used in applications that require high precision data on cm-level. This paper presents a precise process for geolocation of ground targets based on thermal video imagery acquired by small UAV equipped with RTK GPS. The geolocation data is filtered using an extended Kalman filter, which provides a smoothed estimate of target location and target velocity. The accurate geo-locating of targets during image acquisition is conducted via traditional photogrammetric bundle adjustment equations using accurate exterior parameters achieved by on board IMU and RTK GPS sensors, Kalman filtering and interior orientation parameters of thermal camera from pre-flight laboratory calibration process. The results of this study compared with code-based ordinary GPS, indicate that RTK observation with proposed method shows more than 10 times improvement of accuracy in target geolocation.

  6. Congestion and Error Control in Overlay Networks

    OpenAIRE

    Constantinescu, Doru; Erman, David; Dragos ILIE; Popescu, Adrian

    2007-01-01

    In recent years, Internet has known an unprecedented growth, which, in turn, has lead to an increased demand for real-time and multimedia applications that have high Quality-of-Service (QoS) demands. This evolution lead to difficult challenges for the Internet Service Providers (ISPs) to provide good QoS for their clients as well as for the ability to provide differentiated service subscriptions for those clients who are willing to pay more for value added services. Furthermore, a tremendous ...

  7. Overlays for plain jointed concrete pavements

    Science.gov (United States)

    Gulden, W.; Brown, D.

    1984-09-01

    This report describes the construction and performance of 4 concrete and 16 asphalt overlay test sections after nine years of traffic. The test sections were placed on I-85 which carries a substantial number of heavy trucks to determine what treatments and overlay type and thickness would give acceptable performance. The concrete overlay sections were placed in 1975 and consisted of 3 inch, 4 1/2 inch, and 6 inch CRC and 6 inch jointed PCC with 15 ft. and 30 ft. joint spacing. The asphalt sections were placed in 1976 with the variables being overlay thickness of 2 inches, 4 inches, and 6 inches and the placement of two geotextiles and strips of a waterproofing membrane for each overlay thickness. An Arkansas base test section was also included in the experiment.

  8. [Archival tags and geolocation methods for marine animals: A review].

    Science.gov (United States)

    Zhang, Tian-feng; Fan, Wei; Dai, Yang

    2015-11-01

    Archival tags, a group of data storable electronic tags, are widely used as strong tools for obtaining long term and large scale activity information of marine animals, specifically highly migratory oceanic fishes, and corresponding environmental data. Though retrieving tags is an indispensable step for obtaining data, which is a shortage of archival tags, a series of achievements have been made on marine animals by using archival tags since the 1990s. With the appearance of pop-up satellite tag, which solved the problem of data retrieving and was fully independent of the fishing, both breadth and depth of marine animals' studies are extended by the end of the 1990s. Geolocation based on light intensity is the key to estimate marine animals' movement and has achieved some progress in the past 20 years. However, the accuracy of geolocation for latitude is not high enough, and there is still much room for improvement. To date, most geolocation methods that use ambient daylight involve identifying the times when the sun is at a precisely known zenith angle (e.g., sunrise and sunset). The problem of estimating longitude has been proved easy to solve, but accurate latitude estimates remain elusive. This paper mainly introduced two tags, i. e., archival tags and pop-up tags, and three geolocation methods, i.e. , 1) the "fixed reference" method, 2) the "variable reference" method, and 3) the "reflection" method. We also presented a prospect analysis on archival tags and possible research direction of geolocation methods. We believed that miniaturization and multi-sensor integration are the trends for electronic tags while more environmental factors such as depth, SST (sea surface temperature) or magnetic field intensity, instead of single factor, as auxiliary parameters would be used for improving the geolocation accuracy in the future.

  9. Geolocation of North Sea cod (Gadus morhua) using Hidden Markov Models and behavioural switching

    DEFF Research Database (Denmark)

    Pedersen, Martin Wæver; Righton, David; Thygesen, Uffe Høgsbro

    2008-01-01

    When geolocating fish based on archival tag data, a realistic assessment of uncertainty is essential. Here, we describe an application of a novel Fokker–Planck-based method to geolocate Atlantic cod (Gadus morhua) in the North Sea area. In this study, the geolocation relies mainly on matching tidal...

  10. a Geographic Data Gathering System for Image Geolocalization Refining

    Science.gov (United States)

    Semaan, B.; Servières, M.; Moreau, G.; Chebaro, B.

    2017-09-01

    Image geolocalization has become an important research field during the last decade. This field is divided into two main sections. The first is image geolocalization that is used to find out which country, region or city the image belongs to. The second one is refining image localization for uses that require more accuracy such as augmented reality and three dimensional environment reconstruction using images. In this paper we present a processing chain that gathers geographic data from several sources in order to deliver a better geolocalization than the GPS one of an image and precise camera pose parameters. In order to do so, we use multiple types of data. Among this information some are visible in the image and are extracted using image processing, other types of data can be extracted from image file headers or online image sharing platforms related information. Extracted information elements will not be expressive enough if they remain disconnected. We show that grouping these information elements helps finding the best geolocalization of the image.

  11. Geolocating fish using Hidden Markov Models and Data Storage Tags

    DEFF Research Database (Denmark)

    Thygesen, Uffe Høgsbro; Pedersen, Martin Wæver; Madsen, Henrik

    2009-01-01

    Geolocation of fish based on data from archival tags typically requires a statistical analysis to reduce the effect of measurement errors. In this paper we present a novel technique for this analysis, one based on Hidden Markov Models (HMM's). We assume that the actual path of the fish is generated...

  12. Geolocation error tracking of ZY-3 three line cameras

    Science.gov (United States)

    Pan, Hongbo

    2017-01-01

    The high-accuracy geolocation of high-resolution satellite images (HRSIs) is a key issue for mapping and integrating multi-temporal, multi-sensor images. In this manuscript, we propose a new geometric frame for analysing the geometric error of a stereo HRSI, in which the geolocation error can be divided into three parts: the epipolar direction, cross base direction, and height direction. With this frame, we proved that the height error of three line cameras (TLCs) is independent of nadir images, and that the terrain effect has a limited impact on the geolocation errors. For ZY-3 error sources, the drift error in both the pitch and roll angle and its influence on the geolocation accuracy are analysed. Epipolar and common tie-point constraints are proposed to study the bundle adjustment of HRSIs. Epipolar constraints explain that the relative orientation can reduce the number of compensation parameters in the cross base direction and have a limited impact on the height accuracy. The common tie points adjust the pitch-angle errors to be consistent with each other for TLCs. Therefore, free-net bundle adjustment of a single strip cannot significantly improve the geolocation accuracy. Furthermore, the epipolar and common tie-point constraints cause the error to propagate into the adjacent strip when multiple strips are involved in the bundle adjustment, which results in the same attitude uncertainty throughout the whole block. Two adjacent strips-Orbit 305 and Orbit 381, covering 7 and 12 standard scenes separately-and 308 ground control points (GCPs) were used for the experiments. The experiments validate the aforementioned theory. The planimetric and height root mean square errors were 2.09 and 1.28 m, respectively, when two GCPs were settled at the beginning and end of the block.

  13. Overlay degradation induced by film stress

    Science.gov (United States)

    Huang, Chi-hao; Liu, Yu-Lin; Luo, Shing-Ann; Yang, Mars; Yang, Elvis; Hung, Yung-Tai; Luoh, Tuung; Yang, T. H.; Chen, K. C.

    2017-03-01

    The semiconductor industry has continually sought the approaches to produce memory devices with increased memory cells per memory die. One way to meet the increasing storage capacity demand and reduce bit cost of NAND flash memories is 3D stacked flash cell array. In constructing 3D NAND flash memories, increasing the number of stacked layers to build more memory cell number per unit area necessitates many high-aspect-ratio etching processes accordingly the incorporation of thick and unique etching hard-mask scheme has been indispensable. However, the ever increasingly thick requirement on etching hard-mask has made the hard-mask film stress control extremely important for maintaining good process qualities. The residual film stress alters the wafer shape consequently several process impacts have been readily observed across wafer, such as wafer chucking error on scanner, film peeling, materials coating and baking defects, critical dimension (CD) non-uniformity and overlay degradation. This work investigates the overlay and residual order performance indicator (ROPI) degradation coupling with increasingly thick advanced patterning film (APF) etching hard-mask. Various APF films deposited by plasma enhanced chemical vapor deposition (PECVD) method under different deposition temperatures, chemicals combinations, radio frequency powers and chamber pressures were carried out. And -342MPa to +80MPa film stress with different film thicknesses were generated for the overlay performance study. The results revealed the overlay degradation doesn't directly correlate with convex or concave wafer shapes but the magnitude of residual APF film stress, while increasing the APF thickness will worsen the overlay performance and ROPI strongly. High-stress APF film was also observed to enhance the scanner chucking difference and lead to more serious wafer to wafer overlay variation. To reduce the overlay degradation from ever increasingly thick APF etching hard-mask, optimizing the

  14. Network mapping and usage determination

    CSIR Research Space (South Africa)

    Senekal, FP

    2007-07-01

    Full Text Available detection. Based on this information, topology determination techniques can be applied to infer network structure from the information. Techniques to visualise the information are discussed. IP geolocation (the ability to associate a geographical coordinate...

  15. Within a Stone's Throw: Proximal Geolocation of Internet Users via Covert Wireless Signaling

    Energy Technology Data Exchange (ETDEWEB)

    Paul, Nathanael R [ORNL; Shue, Craig [Worcester Polytechnic Institute, Worcester; Taylor, Curtis [Worcester Polytechnic Institute, Worcester

    2013-01-01

    While Internet users may often believe they have anonymity online, a culmination of technologies and recent research may allow an adversary to precisely locate an online user s geophysical location. In many cases, such as peer-to-peer applications, an adversary can easily use a target s IP address to quickly obtain the general geographical location of the target. Recent research has scoped this general area to a 690m (0.43 mile) radius circle. In this work, we show how an adversary can exploit Internet communication for geophysical location by embedding covert signals in communication with a target on a remote wireless local area network. We evaluated the approach in two common real-world settings: a residential neighborhood and an apartment building. In the neighborhood case, we used a single-blind trial in which an observer located a target network to within three houses in less than 40 minutes. Directional antennas may have allowed even more precise geolocation. This approach had only a 0.38% false positive rate, despite 24,000 observed unrelated packets and many unrelated networks. This low rate allowed the observer to exclude false locations and continue searching for the target. Our results enable law enforcement or copyright holders to quickly locate online Internet users without requiring time-consuming subpoenas to Internet Service Providers. Other privacy use cases include rapidly locating individuals based on their online speech or interests. We hope to raise awareness of these issues and to spur discussion on privacy and geolocating techniques.

  16. Scalable Lunar Surface Networks and Adaptive Orbit Access Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Innovative network architecture, protocols, and algorithms are proposed for both lunar surface networks and orbit access networks. Firstly, an overlaying...

  17. Real-Time Geolocation with a Satellite Formation

    OpenAIRE

    Leiter, Noam

    2013-01-01

    Space-borne geolocation with a small satellite formation could provide accurate tracking of a Mars rover, a redundant navigation system in a jammed GNNS environment, or a cost-effective system for autonomously locating distress signals. In this study we demonstrate how a cluster of two or three Low Earth Orbit (LEO) satellites performing sequential time difference of arrival measurements could accurately determine the position of a terrestrial source emitting electromagnetic pulses. Whereas T...

  18. Credit card fraud detection using neural network and geolocation

    Science.gov (United States)

    Gulati, Aman; Dubey, Prakash; MdFuzail, C.; Norman, Jasmine; Mangayarkarasi, R.

    2017-11-01

    The most acknowledged payment mode is credit card for both disconnected and online mediums in today's day and age. It facilitates cashless shopping everywhere in the world. It is the most widespread and reasonable approach with regards to web based shopping, paying bills, what's more, performing other related errands. Thus danger of fraud exchanges utilizing credit card has likewise been expanding. In the Current Fraud Detection framework, false exchange is recognized after the transaction is completed. As opposed to the current system, the proposed system presents a methodology which facilitates the detection of fraudulent exchanges while they are being processed, this is achieved by means of Behaviour and Locational Analysis(Neural Logic) which considers a cardholder's way of managing money and spending pattern. A deviation from such a pattern will then lead to the system classifying it as suspicious transaction and will then be handled accordingly.

  19. Patent Overlay Mapping: Visualizing Technological Distance

    CERN Document Server

    Kay, Luciano; Youtie, Jan; Porter, Alan L; Rafols, Ismael

    2012-01-01

    The purpose of this paper is to present a new global patent map that represents all technological categories, and a method to locate patent data of individual organizations and technological fields on the global map. This second patent overlay map technique is shown to be of potential interest to support competitive intelligence and policy decision-making. The global patent map is based on similarities in citing-to-cited relationships between categories of the International Patent Classification (IPC) of European Patent Office (EPO) patents from 2000 to 2006. This patent dataset, extracted from PatStat database, represents more than 760,000 patent records in more than 400 IPC categories. To illustrate the kind of analytical support offered by this approach, the paper shows the overlay of nanotechnology-related patenting activities of two companies and two different nanotechnology subfields on to the global patent map. The exercise shows the potential of patent overlay maps to visualize technological areas and...

  20. Weld overlay coatings for erosion control

    Energy Technology Data Exchange (ETDEWEB)

    Levin, B.; DuPont, J.N.; Marder, A.R.

    1993-03-03

    A literature review was made. In spite of similarities between abrasive wear and solid particle erosion, weld overlay hardfacing alloys that exhibit high abrasion resistance may not necessarily have good erosion resistance. The performance of weld overlay hardfacing alloys in erosive environments has not been studied in detail. It is believed that primary-solidified hard phases such as carbides and intermetallic compounds have a strong influence on erosion resistance of weld overlay hardfacing alloys. However, relationships between size, shape, and volume fraction of hard phases in a hardfacing alloys and erosion resistance were not established. Almost all hardfacing alloys can be separated into two major groups based upon chemical compositions of the primary solidified hard phases: (a) carbide hardening alloys (Co-base/carbide, WC-Co and some Fe base superalloys); and (b) intermetallic hardening alloys (Ni-base alloys, austenitic steels, iron-aluminides).

  1. Exploring overlay journals: the RIOJA project

    CERN Multimedia

    CERN. Geneva

    2007-01-01

    Researchers in cosmology and astrophysics depend on the arXiv repository for the registration and dissemination of their work, as well as for current awareness, yet they continue to submit papers to journals for review. Could rapid quality certification be overlaid directly onto the arXiv repository? This presentation introduces the RIOJA (Repository Interface to Overlaid Journal Archives) project, on which a group of cosmology researchers from the UK is working with UCL Library Services and Cornell University. The project is creating a tool to support the overlay of journals onto repositories, and will demonstrate a cosmology journal overlaid on top of arXiv. RIOJA will also work with the cosmology community to explore the social and economic aspects of journal overlay in this discipline: what other value, besides the quality stamp, does journal publication typically add? What are the costs of the ideal overlay journal for this community, and how could those costs be recovered? Would researchers real...

  2. DCM: device correlated metrology for overlay measurements

    Science.gov (United States)

    Chen, Charlie; Huang, George K. C.; Pai, Yuan Chi; Wu, Jimmy C. H.; Cheng, Yu Wei; Hsu, Simon C. C.; Yu, Chun Chi; Amir, Nuriel; Choi, Dongsub; Itzkovich, Tal; Tarshish-Shapir, Inna; Tien, David C.; Huang, Eros; Kuo, Kelly T. L.; Kato, Takeshi; Inoue, Osamu; Kawada, Hiroki; Okagawa, Yutaka; Huang, Luis; Hsu, Matthew; Su, Amei

    2013-04-01

    One of the main issues with overlay error metrology accuracy is the bias between results based on overlay (OVL) targets and actual device overlay error. In this study, we introduce the concept of Device Correlated Metrology (DCM), which is a systematic approach to quantifying and overcoming the bias between target-based overlay results and device overlay issues. For systematically quantifying the bias components between target and device, we introduce a new hybrid target integrating an optical OVL target with a device mimicking CD-SEM (Critical Dimension - Scanning Electron Microscope) target. The hybrid OVL target is designed to accurately represent the process influence found on the real device. In the general case, the CD-SEM can measure the bias between target and device on the same layer at AEI (After Etch Inspection) for all layers, the OVL between layers at AEI for most cases and at ADI (After Develop Inspection) for limited cases such as DPL (Double Patterning Lithography). The results shown demonstrate that for the new process compatible hybrid targets the bias between target and device is small, of the order of CD-SEM measurement uncertainty. Direct OVL measurements by CD-SEM show excellent correlation with optical OVL measurements in certain conditions. This correlation helps verify the accuracy of the optical measurement results and is applicable for imaging based OVL metrology methods using AIM or AIMid OVL targets, and scatterometry-based overlay methods such as SCOL (Scatterometry OVL). Future plans include broadening the hybrid target design to better mimic each layer's process conditions such as pattern density. We are also designing hybrid targets for memory devices.

  3. 3D Geolocation of current pulses in clouds using a 6-axis EB vector sensor Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Lightning discharges within or near critical facilities can disrupt activities or result in damage. Although existing lightning locating systems can geolocate...

  4. Effect of geolocators on migration and subsequent breeding performance of a long-distance passerine migrant.

    Directory of Open Access Journals (Sweden)

    Debora Arlt

    Full Text Available Geolocators are small light-weight data loggers used to track individual migratory routes, and their use has increased exponentially in birds. However, the effects of geolocators on individual performance are still poorly known. We studied geolocator effects on a long-distance migrating passerine bird, the northern wheatear (Oenanthe oenanthe L.. We asked the general question of whether geolocators affect migratory behaviour and subsequent reproductive performance of small passerines by comparing arrival time, breeding time, breeding success and survival of geolocator versus control birds of known identity and breeding history. During two years geolocator birds (n=37 displayed a lower apparent survival (30% as compared to controls (45%, n=164. Furthermore, returning geolocator birds (n=12 arrived on average 3.5 days later, started laying eggs 6.3 days later, and had lower nest success (25% than control birds (78%. Our results suggest that geolocators affect migratory performance with carry-over effects to the timing of breeding and reproductive success in the subsequent breeding season. We discuss the implications of such geolocator effects for the study of migratory strategies of small passerines in general and suggest how to identify and investigate such effects in the future.

  5. KML Super Overlay to WMS Translator

    Science.gov (United States)

    Plesea, Lucian

    2007-01-01

    This translator is a server-based application that automatically generates KML super overlay configuration files required by Google Earth for map data access via the Open Geospatial Consortium WMS (Web Map Service) standard. The translator uses a set of URL parameters that mirror the WMS parameters as much as possible, and it also can generate a super overlay subdivision of any given area that is only loaded when needed, enabling very large areas of coverage at very high resolutions. It can make almost any dataset available as a WMS service visible and usable in any KML application, without the need to reformat the data.

  6. An Efficient Method for Performance Evaluation of Femto-Macro Overlay Systems

    DEFF Research Database (Denmark)

    Huang, Yue-Cai; Ko, King-Tim; Huang, Qian

    2011-01-01

    This paper considers a two-tier femto-macro overlay network architecture, where groups of femtocells are overlaid by macrocells. The capacity of the femtocells is limited, thus redirection of blocked femto calls to the overlaid macrocell is used as a QoS assurance strategy. Similar overflow appro...

  7. Improved Intelligent Underlay-Overlay Combined with Frequency Hopping in GSM

    DEFF Research Database (Denmark)

    Wigard, Jeroen; Nielsen, Thomas Toftegaard; Mogensen, Preben Elgaard

    1997-01-01

    IUO (intelligent underlay-overlay) in a combination with random frequency hopping in GSM is analysed. Several improvements to the original IUO concept analysed in Nielsen et al. (1997) are introduced. With the improved IUO concept it is possible to load a network configuration consisting of 4...

  8. Cracking and debonding of a thin fiber reinforced concrete overlay.

    Science.gov (United States)

    2017-04-01

    Previous field studies suggested that macro-fibers incorporated in thin overlay pavements will result in reduced crack opening widths, vertical deflections, and debonding rates compared to that of unreinforced overlays. A simple finite element (FE) m...

  9. Colors, colored overlays, and reading skills

    Directory of Open Access Journals (Sweden)

    Arcangelo eUccula

    2014-07-01

    Full Text Available In this article, we are concerned with the role of colors in reading written texts. It has been argued that colored overlays applied above written texts positively influence both reading fluency and reading speed. These effects would be particularly evident for those individuals affected by the so called Meares-Irlen syndrome, i.e. who experience eyestrain and/or visual distortions – e.g. color, shape or movement illusions – while reading. This condition would interest the 12-14% of the general population and up to the 46% of the dyslexic population. Thus, colored overlays have been largely employed as a remedy for some aspects of the difficulties in reading experienced by dyslexic individuals, as fluency and speed. Despite the wide use of colored overlays, how they exert their effects has not been made clear yet. Also, according to some researchers, the results supporting the efficacy of colored overlays as a tool for helping readers are at least controversial. Furthermore, the very nature of the Meares-Irlen syndrome has been questioned. Here we provide a concise, critical review of the literature.

  10. CO Chemisorption at Metal Surfaces and Overlayers

    DEFF Research Database (Denmark)

    Hammer, Bjørk; Morikawa, Y.; Nørskov, Jens Kehlet

    1996-01-01

    A database of ab initio calculations of the chemisorption energy of CO over Ni(111), Cu(111), Ru(0001), Pd(111), Ag(111), Pt(111), Au(111), Cu3Pt(111), and some metallic overlayer structures is presented. The trends can be reproduced with a simple model describing the interaction between the meta...

  11. Information Exchange rather than Topology Awareness: Cooperation between P2P Overlay and Traffic Engineering

    Directory of Open Access Journals (Sweden)

    Jia Zhao

    2014-01-01

    Full Text Available Solutions to the routing strategic conflict between noncooperative P2P overlay and ISP underlay go separate ways: hyperselfishness and cooperation. Unpredictable (possibly adverse impact of the hyperselfish topology awareness, which is adopted in both overlay routing and traffic engineering, has not been sufficiently studied in the literature. Topology-related information exchange in a cooperatively efficient way should be highlighted to alleviate the cross-layer conflict. In this paper, we first illustrate the hyperselfish weakness with two dynamic noncooperative game models in which hyperselfish overlay or underlay has to accept a suboptimal profit. Then we build a synergistic cost-saving (SC game model to reduce the negative effects of noncooperation. In the SC model, through information exchange, that is, the classified path-delay metrics for P2P overlay and peer locations for underlay, P2P overlay selects proximity as well as saving traffic transit cost for underlay, and ISP underlay adjusts routing to optimize network cost as well as indicating short delay paths for P2P. Simulations based on the real and generated topologies validate cost improvement by SC model and find a proper remote threshold value to limit P2P traffic from remote area, cross-AS, or cross-ISP.

  12. GPS-free geolocation using LoRa in low-power WANs

    DEFF Research Database (Denmark)

    Fargas, Bernat Carbones; Petersen, Martin Nordal

    2017-01-01

    Internet of Things (IoT) has been growing over the last few years in multiple applications and due to a growing need for geolocation and tracking capabilities, an innovative opportunity arises. Whereas geolocation is traditionally based on GPS units this paper reports on a design and implementation...

  13. Overlay metrology tool calibration using blossom

    Science.gov (United States)

    Binns, Lewis A.; Smith, Nigel P.; Dasari, Prasad

    2008-03-01

    As overlay budgets continue to shrink, there is an increasing need to more fully characterize the tools used to measure overlay. In a previous paper, it was shown how a single-layer Blossom overlay target could be utilized to measure aberrations across the field of view of an overlay tool in an efficient and low-cost manner. In this paper, we build upon this method, and discuss the results obtained, and experiences gained in applying this method to a fleet of currently operational overlay tools. In particular, the post-processing of the raw calibration data is discussed in detail, and a number of different approaches are considered. The quadrant-based and full-field based methods described previously are compared, along with a half-field method. In each case we examine a number of features, including the trade off between ease of use (including the total number of measurements required) versus sensitivity / potential signal to noise ratio. We also examine how some techniques are desensitized to specific types of tool or mark aberration, and suggest how to combine these with non-desensitized methods to quickly identify these anomalies. There are two distinct applications of these tool calibration methods. Firstly, they can be used as part of the tool build and qualification process, to provide absolute metrics of imaging quality. Secondly, they can be of significant assistance in diagnosing tool or metrology issues or providing preventative maintenance diagnostics, as (as shown previously) under normal operation the results show very high consistency, even compared to aggressive overlay requirements. Previous work assumed that the errors in calibration, from reticle creation through to the metrology itself, would be Gaussian in nature; in this paper we challenge that assumption, and examine a specific scenario that would lead to very non-Gaussian behavior. In the tool build / qualification application, most scenarios lead to a systematic trend being superimposed

  14. ZY3-02 Laser Altimeter Footprint Geolocation Prediction.

    Science.gov (United States)

    Xie, Junfeng; Tang, Xinming; Mo, Fan; Li, Guoyuan; Zhu, Guangbin; Wang, Zhenming; Fu, Xingke; Gao, Xiaoming; Dou, Xianhui

    2017-09-21

    Successfully launched on 30 May 2016, ZY3-02 is the first Chinese surveying and mapping satellite equipped with a lightweight laser altimeter. Calibration is necessary before the laser altimeter becomes operational. Laser footprint location prediction is the first step in calibration that is based on ground infrared detectors, and it is difficult because the sample frequency of the ZY3-02 laser altimeter is 2 Hz, and the distance between two adjacent laser footprints is about 3.5 km. In this paper, we build an on-orbit rigorous geometric prediction model referenced to the rigorous geometric model of optical remote sensing satellites. The model includes three kinds of data that must be predicted: pointing angle, orbit parameters, and attitude angles. The proposed method is verified by a ZY3-02 laser altimeter on-orbit geometric calibration test. Five laser footprint prediction experiments are conducted based on the model, and the laser footprint prediction accuracy is better than 150 m on the ground. The effectiveness and accuracy of the on-orbit rigorous geometric prediction model are confirmed by the test results. The geolocation is predicted precisely by the proposed method, and this will give a reference to the geolocation prediction of future land laser detectors in other laser altimeter calibration test.

  15. ZY3-02 Laser Altimeter Footprint Geolocation Prediction

    Directory of Open Access Journals (Sweden)

    Junfeng Xie

    2017-09-01

    Full Text Available Successfully launched on 30 May 2016, ZY3-02 is the first Chinese surveying and mapping satellite equipped with a lightweight laser altimeter. Calibration is necessary before the laser altimeter becomes operational. Laser footprint location prediction is the first step in calibration that is based on ground infrared detectors, and it is difficult because the sample frequency of the ZY3-02 laser altimeter is 2 Hz, and the distance between two adjacent laser footprints is about 3.5 km. In this paper, we build an on-orbit rigorous geometric prediction model referenced to the rigorous geometric model of optical remote sensing satellites. The model includes three kinds of data that must be predicted: pointing angle, orbit parameters, and attitude angles. The proposed method is verified by a ZY3-02 laser altimeter on-orbit geometric calibration test. Five laser footprint prediction experiments are conducted based on the model, and the laser footprint prediction accuracy is better than 150 m on the ground. The effectiveness and accuracy of the on-orbit rigorous geometric prediction model are confirmed by the test results. The geolocation is predicted precisely by the proposed method, and this will give a reference to the geolocation prediction of future land laser detectors in other laser altimeter calibration test.

  16. ATLAS Pile-up and Overlay Simulation

    CERN Document Server

    Novak, Tadej; The ATLAS collaboration

    2017-01-01

    The high luminosity of the LHC results in a significant background to interesting physics events known as pile-up. ATLAS uses several methods for simulating the effects of pile-up. The mostly used method is a direct simulation of background events where multiple simulated background events are combined for each physics event. For some physics processes, a more accurate simulation can be achieved by overlaying real proton-proton collisions on a simulated hard-scatter process. Overlay is also being investigated for a premixed pile-up background to reduce CPU usage and I/O stress during the simulation. Embedding replaces the muons found in Z→mumu decays in data with simulated taus at the same 4-momenta, thus preserving the underlying event and pileup from the original data event. This talk compares the pile-up simulation methods used at the ATLAS experiment pointing their benefits and drawbacks.

  17. Overlay cognitive radio systems with adaptive two-way relaying

    KAUST Repository

    Hyadi, Amal

    2013-12-01

    In this paper, we propose a spectrum sharing mechanism with a two-phase two-way relaying protocol for an overlay cognitive network. The system comprises two primary users (PUs) and two secondary users (SUs). One of the SUs acts as a relay for the PUs and gains spectrum sharing as long as he respects outage probability constraints of the primary system. Moreover, we consider that the relaying node performs an optimal power allocation scheme that minimizes the outage performance of the secondary receiver. Closed form expressions for the outage probability are derived for the cases of Decode-and-Forward (DF), Amplify-and-Forward (AF), and adaptive relaying. Numerical simulations are presented to illustrate and compare the obtained results. © 2013 IEEE.

  18. Assessing costs of carrying geolocators using feather corticosterone in two species of aerial insectivore.

    Science.gov (United States)

    Fairhurst, Graham D; Berzins, Lisha L; Bradley, David W; Laughlin, Andrew J; Romano, Andrea; Romano, Maria; Scandolara, Chiara; Ambrosini, Roberto; Dawson, Russell D; Dunn, Peter O; Hobson, Keith A; Liechti, Felix; Marchant, Tracy A; Norris, D Ryan; Rubolini, Diego; Saino, Nicola; Taylor, Caz M; Whittingham, Linda A; Clark, Robert G

    2015-05-01

    Despite benefits of using light-sensitive geolocators to track animal movements and describe patterns of migratory connectivity, concerns have been raised about negative effects of these devices, particularly in small species of aerial insectivore. Geolocators may act as handicaps that increase energetic expenditure, which could explain reported effects of geolocators on survival. We tested this 'Energetic Expenditure Hypothesis' in 12 populations of tree swallows (Tachycineta bicolor) and barn swallows (Hirundo rustica) from North America and Europe, using measurements of corticosterone from feathers (CORTf) grown after deployment of geolocators as a measure of physiology relevant to energetics. Contrary to predictions, neither among- (both species) nor within-individual (tree swallows only) levels of CORTf differed with respect to instrumentation. Thus, to the extent that CORTf reflects energetic expenditure, geolocators apparently were not a strong handicap for birds that returned post-deployment. While this physiological evidence suggests that information about migration obtained from returning geolocator-equipped swallows is unbiased with regard to levels of stress, we cannot discount the possibility that corticosterone played a role in reported effects of geolocators on survival in birds, and suggest that future studies relate corticosterone to antecedent factors, such as reproductive history, and to downstream fitness costs.

  19. Life extension of boilers using weld overlay protection

    Energy Technology Data Exchange (ETDEWEB)

    Lai, G.; Hulsizer, P. [Welding Services Inc., Norcross, GA (United States); Brooks, R. [Welding Services Inc., Welding Services Europe, Spijkenisse (Netherlands)

    1998-12-31

    The presentation describes the status of modern weld overlay technology for refurbishment, upgrading and life extension of boilers. The approaches to life extension of boilers include field overlay application, shop-fabricated panels for replacement of the worn, corroded waterwall and shop-fabricated overlay tubing for replacement of individual tubes in superheaters, generating banks and other areas. The characteristics of weld overlay products are briefly described. Also discussed are successful applications of various corrosion-resistant overlays for life extension of boiler tubes in waste-to-energy boilers, coal-fired boilers and chemical recovery boilers. Types of corrosion and selection of weld overlay alloys in these systems are also discussed. (orig.) 14 refs.

  20. The hilum overlay sign in a child

    Directory of Open Access Journals (Sweden)

    M J Van Wyk

    2010-12-01

    Full Text Available A 9-month-old girl presented with a 1-month history of coughing. A chest X-ray (CXR was performed, and the antero-posterior view demonstrated the hilum overlay sign. Furthermore, there was absence of the azygo-oesophageal line and bilateral paraspinal lines. The lateral CXR revealed a posterior mediastinal mass. Subsequently, a computed tomogram of the chest confirmed a posterior mediastinal mass, with calcifications and intraspinal extension consistent with neuroblastoma. Histological analysis confirmed this mass as a neuroblastoma.

  1. Overlay performance with advanced ATHENA trademark alignment strategies

    CERN Document Server

    Huijbregtse, Jeroen; Jeunink, Andre; Megens, Henry; Navarro, Ramon; Simons, Geert; Swinnen, Bart; Tolsma, Hoite; Van Bilsen, Frank; Van Haren, Richard

    2003-01-01

    The introduction of the ATHENA**T**M alignment sensor has made advanced applications of the sensor data increasingly important to meet the tightening overlay specifications for future technology nodes. As part of the total overlay budget, the effects of different alignment strategies on overlay performance need to be investigated. Keeping in mind that such strategies are simple and easy to use, two developments are addressed: advanced alignment recipes and advanced mark designs. (Edited abstract) 8 Refs.

  2. VT Data - Cons/Rec Overlay District 20110301, Winhall

    Data.gov (United States)

    Vermont Center for Geographic Information — Conservation and Recreatioal Protection overaly districts for the Town of Winhall, Vermont. Other overlay districts (Transfer of Development Rights, and Scenic...

  3. IceBridge NSERC L1B Geolocated Meteorologic and Surface Temperature Data, Version 1

    Data.gov (United States)

    National Aeronautics and Space Administration — The IceBridge National Suborbital Education & Research Center (NSERC) L1B Geolocated Meteorologic and Surface Temperature (IAMET1B) data set is a collection of...

  4. IceBridge Photon Counting Lidar L1B Unclassified Geolocated Photon Elevations V001

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set contains geolocated photon elevations captured over Antarctica using the Sigma Space photon counting lidar. The data were collected by scientists...

  5. MLS/Aura L1 Orbit/Attitude and Tangent Point Geolocation Data V004

    Data.gov (United States)

    National Aeronautics and Space Administration — ML1OA is the EOS Aura Microwave Limb Sounder (MLS) product containing the level 1 orbit attitude and tangent point geolocation data. The current version is 4.2. Data...

  6. IceBridge UAF Lidar Profiler L1B Geolocated Surface Elevation Triplets

    Data.gov (United States)

    National Aeronautics and Space Administration — The NASA IceBridge UAF Lidar Profiler L1B Geolocated Surface Elevation Triplets data set contains surface profiles of Alaska Glaciers acquired using the airborne...

  7. MLS/Aura L1 Orbit/Attitude and Tangent Point Geolocation Data V002

    Data.gov (United States)

    National Aeronautics and Space Administration — ML1OA is the EOS Aura Microwave Limb Sounder (MLS) product containing the level 1 orbit attitude and tangent point geolocation data. The current version is 2.3. Data...

  8. MODIS/Terra Geolocation Fields 5-Min L1A Swath 1km V005

    Data.gov (United States)

    National Aeronautics and Space Administration — The geolocation fields are calculated for each 1 km MODIS Instantaneous Field of Views (IFOV) for all orbits daily. The locations and ancillary information...

  9. IceBridge LVIS L1B Geolocated Return Energy Waveforms V002

    Data.gov (United States)

    National Aeronautics and Space Administration — The IceBridge LVIS L1B Geolocated Return Energy Waveforms (ILVIS1B) data set contains Greenland and Antarctica laser altimetry return energy waveform measurements...

  10. IceBridge NSERC L1B Geolocated Meteorologic and Surface Temperature Data

    Data.gov (United States)

    National Aeronautics and Space Administration — The IceBridge National Suborbital Education & Research Center (NSERC) L1B Geolocated Meteorologic and Surface Temperature (IAMET1B) data set is a collection of...

  11. IceBridge Geometrics 823A Cesium Magnetometer L2 Geolocated Magnetic Anomalies, Version 1

    Data.gov (United States)

    National Aeronautics and Space Administration — The NASA IceBridge Geometrics 823A Cesium Magnetometer L2 Geolocated Magnetic Anomalies (IMGEO2) data set contains magnetic anomaly measurements taken over...

  12. IceBridge Riegl Laser Altimeter L2 Geolocated Surface Elevation Triplets V001

    Data.gov (United States)

    National Aeronautics and Space Administration — The IceBridge Riegl Laser Altimeter L2 Geolocated Surface Elevation Triplets (ILUTP2) data set contains surface range values for Antarctica and Greenland derived...

  13. Pre-IceBridge MCoRDS L1B Geolocated Radar Echo Strength Profiles

    Data.gov (United States)

    National Aeronautics and Space Administration — The Pre-IceBridge MCoRDS L1B Geolocated Radar Echo Strength Profiles (BRMCR1B) data set contains Arctic and Antarctic radio echo-sounding measurements taken from the...

  14. IceBridge HiCARS 1 L2 Geolocated Ice Thickness

    Data.gov (United States)

    National Aeronautics and Space Administration — The NASA IceBridge HiCARS 1 Level-2 Geolocated Ice Thickness (IR1HI2) data set contains Ice Thickness, Surface Elevations, and Bed Elevation measurements taken over...

  15. AIRS/Aqua Level 1B Infrared (IR) geolocated and calibrated radiances V005

    Data.gov (United States)

    National Aeronautics and Space Administration — The AIRS Infrared (IR) level 1B data set contains AIRS infrared calibrated and geolocated radiances in milliWatts/m^2/cm^-1/steradian. This data set is generated...

  16. IceBridge Geometrics 823A Cesium Magnetometer L2 Geolocated Magnetic Anomalies

    Data.gov (United States)

    National Aeronautics and Space Administration — The NASA IceBridge Geometrics 823A Cesium Magnetometer L2 Geolocated Magnetic Anomalies (IMGEO2) data set contains magnetic anomaly measurements taken over...

  17. IceBridge Riegl Laser Altimeter L2 Geolocated Surface Elevation Triplets

    Data.gov (United States)

    National Aeronautics and Space Administration — The IceBridge Riegl Laser Altimeter L2 Geolocated Surface Elevation Triplets (ILUTP2) data set contains surface range values for Antarctica and Greenland derived...

  18. Assessment of the NOAA S-NPP VIIRS Geolocation Reprocessing Improvements

    Directory of Open Access Journals (Sweden)

    Wenhui Wang

    2017-09-01

    Full Text Available Long-term time series analysis requires consistent data records from satellites. The Visible Infrared Imaging Radiometer Suite (VIIRS onboard the Suomi National Polar orbiting Partner (S-NPP satellite launched in 2011 requires a major effort to produce consistently calibrated sensor data records (SDR. Accurate VIIRS geolocation products are critical to other VIIRS products and products from other instruments on the S-NPP satellite. This paper presents methods for assessing major improvements to the VIIRS geolocation products in the ongoing National Oceanic and Atmospheric Administration (NOAA/Center for Satellite Applications and Research (STAR reprocessing that incorporates all corrections in calibration parameters and SDR algorithms since launch to present. In this study, we analyzed the history of VIIRS geometric calibration parameter updates to identify optimal parameters to account for geolocation errors in the early days of the mission. A sample area located in North Western Africa was selected for validation purposes after analyzing global VIIRS and Landsat control point matching results. Geolocation products over the study region were reprocessed and I-bands/M-bands geolocation improvements were characterized by comparing geolocation errors before and after the reprocessing. Our results indicate that all short-term geolocation anomalies before the latest operational geometric calibration parameter update on 22 August 2013 were effectively minimized after reprocessing, with geolocation errors reduced from −47.1 ± 83.8 m to −23.3 ± 51.1 m (along scan and from −15.6 ± 43.6 m to −5.9 ± 37.7 m (along track. Terrain correction for the VIIRS Day-Night-Band (DNB was not implemented in the NOAA operational processing until 22 May 2015. In the reprocessing, it will be implemented to the entire DNB geolocation data record. DNB reprocessing improvement due to this implementation was evaluated using nighttime observations over point

  19. Investigation of Iron Aluminide Weld Overlays

    Energy Technology Data Exchange (ETDEWEB)

    Banovic, S.W.; DuPont, J.B.; Levin, B.F.; Marder, A.R.

    1999-08-02

    Conventional fossil fired boilers have been retrofitted with low NO(sub)x burners in order for the power plants to comply with new clean air regulations. Due to the operating characteristics of these burners, boiler tube sulfidation corrosion typically has been enhanced resulting in premature tube failure. To protect the existing panels from accelerated attack, weld overlay coatings are typically being applied. By depositing an alloy that offers better corrosion resistance than the underlying tube material, the wastage rates can be reduced. While Ni-based and stainless steel compositions are presently providing protection, they are expensive and susceptible to failure via corrosion-fatigue due to microsegregation upon solidification. Another material system presently under consideration for use as a coating in the oxidation/sulfidation environments is iron-aluminum. These alloys are relatively inexpensive, exhibit little microsegregation, and show excellent corrosion resistance. However, their use is limited due to weldability issues and their lack of corrosion characterization in simulated low NO(sub)x gas compositions. Therefore a program was initiated in 1996 to evaluate the use of iron-aluminum weld overlay coatings for erosion/corrosion protection of boiler tubes in fossil fired boilers with low NO(sub)x burners. Investigated properties included weldability, corrosion behavior, erosion resistance, and erosion-corrosion performance.

  20. Cognitive Radio and TV White Space Communications: TV White Space Geo-location Database System

    OpenAIRE

    Zurutuza, Naroa

    2011-01-01

    The aim of this thesis is to research in the use of emerging TV white space communications, implementing a geo-location database system. For that, some research and theoretical studies related to cognitive radio and TV white space communications will be done first, focusing on current activities, standarization processes, commercial approaches and related projects. Once the background and the present TV white space communications status is analyzed, a geolocation database system will be desig...

  1. Towards Dynamic Real-Time Geo-location Databases for TV White Spaces

    OpenAIRE

    Saeed, Ahmed; Ibrahim, Mohamed; Youssef, Moustafa; Harras, Khaled A.

    2013-01-01

    Recent FCC regulations on TV white spaces allow geo-location databases to be the sole source of spectrum information for White Space Devices (WSDs). Geo-location databases protect TV band incumbents by keeping track of TV transmitters and their protected service areas based on their location, transmission parameters and sophisticated propagation models. In this article, we argue that keeping track of both TV transmitters and TV receivers (i.e. TV sets) can achieve significant improvement in t...

  2. Experimental Simulation-Based Performance Evaluation of an SMS-Based Emergency Geolocation Notification System

    OpenAIRE

    Isibor Osebor; Sanjay Misra; Nicholas Omoregbe; Adewole Adewumi; Luis Fernandez-Sanz

    2017-01-01

    In an emergency, a prompt response can save the lives of victims. This statement generates an imperative issue in emergency medical services (EMS). Designing a system that brings simplicity in locating emergency scenes is a step towards improving response time. This paper therefore implemented and evaluated the performance of an SMS-based emergency geolocation notification system with emphasis on its SMS delivery time and the system’s geolocation and dispatch time. Using the RAS metrics recom...

  3. Disambiguation of Patent Inventors and Assignees Using High-Resolution Geolocation Data

    CERN Document Server

    Morrison, Greg; Pammolli, Fabio

    2016-01-01

    Patent data represent a significant source of information on innovation and the evolution of technology through networks of citations, co-invention and co-assignment of new patents. A major obstacle to extracting useful information from this data is the problem of name disambiguation: linking alternate spellings of individuals or institutions to a single identifier to uniquely determine the parties involved in the creation of a technology. In this paper, we describe a new algorithm that uses high-resolution geolocation to disambiguate both inventor and assignees on more than 3.6 million patents found in the European Patent Office (EPO), under the Patent Cooperation treaty (PCT), and in the US Patent and Trademark Office (USPTO). We show that our algorithm has both high precision and recall in comparison to a manual disambiguation of EPO assignee names in Boston and Paris, and show it performs well for a benchmark of USPTO inventor names that can be linked to a high-resolution address (but poorly for inventors...

  4. Disambiguation of patent inventors and assignees using high-resolution geolocation data

    Science.gov (United States)

    Morrison, Greg; Riccaboni, Massimo; Pammolli, Fabio

    2017-01-01

    Patent data represent a significant source of information on innovation, knowledge production, and the evolution of technology through networks of citations, co-invention and co-assignment. A major obstacle to extracting useful information from this data is the problem of name disambiguation: linking alternate spellings of individuals or institutions to a single identifier to uniquely determine the parties involved in knowledge production and diffusion. In this paper, we describe a new algorithm that uses high-resolution geolocation to disambiguate both inventors and assignees on about 8.5 million patents found in the European Patent Office (EPO), under the Patent Cooperation Treaty (PCT), and in the US Patent and Trademark Office (USPTO). We show this disambiguation is consistent with a number of ground-truth benchmarks of both assignees and inventors, significantly outperforming the use of undisambiguated names to identify unique entities. A significant benefit of this work is the high quality assignee disambiguation with coverage across the world coupled with an inventor disambiguation (that is competitive with other state of the art approaches) in multiple patent offices. PMID:28509897

  5. Finite elements simulation of reflective cracking in asphaltic overlays

    NARCIS (Netherlands)

    Scarpas, A.; De Bondt, A.H.

    Overlaying is one of the most popular and cost effective techniques of rehabilitation of cracked pavements. The placing of reinforcement between the overlay and the top layer of the cracked pavement is currently being utilised as a possible technique for delaying the development of cracks into the

  6. Finite elements simulation of reflective cracking in asphaltic overlays

    NARCIS (Netherlands)

    Scarpas, A.; De Bondt, A.H.

    1996-01-01

    Overlaying is one of the most popular and cost effective techniques of rehabilitation of cracked pavements. The placing of reinforcement between the overlay and the top layer of the cracked pavement is currently being utilised as a possible technique for delaying the development of cracks into the

  7. Strategic intelligence on emerging technologies: Scientometric overlay mapping

    NARCIS (Netherlands)

    Rotolo, D.; Rafols, I.; Hopkins, M.M.; Leydesdorff, L.

    This paper examines the use of scientometric overlay mapping as a tool of “strategic intelligence” to aid the governing of emerging technologies. We develop an integrative synthesis of different overlay mapping techniques and associated perspectives on technological emergence across geographical,

  8. Improving text recognition by distinguishing scene and overlay text

    Science.gov (United States)

    Quehl, Bernhard; Yang, Haojin; Sack, Harald

    2015-02-01

    Video texts are closely related to the content of a video. They provide a valuable source for indexing and interpretation of video data. Text detection and recognition task in images or videos typically distinguished between overlay and scene text. Overlay text is artificially superimposed on the image at the time of editing and scene text is text captured by the recording system. Typically, OCR systems are specialized on one kind of text type. However, in video images both types of text can be found. In this paper, we propose a method to automatically distinguish between overlay and scene text to dynamically control and optimize post processing steps following text detection. Based on a feature combination a Support Vector Machine (SVM) is trained to classify scene and overlay text. We show how this distinction in overlay and scene text improves the word recognition rate. Accuracy of the proposed methods has been evaluated by using publicly available test data sets.

  9. Weld overlay cladding with iron aluminides

    Energy Technology Data Exchange (ETDEWEB)

    Goodwin, G.M. [Oak Ridge National Lab., TN (United States)

    1995-08-01

    The hot and cold cracking tendencies of some early iron aluminide alloy compositions have limited their use in applications where good weldability is required. Using hot crack testing techniques invented at ORNL, and experimental determinations of preheat and postweld heat treatment needed to avoid cold cracking, we have developed iron aluminide filler metal compositions which can be successfully used to weld overlay clad various substrate materials, including 9Cr-1Mo steel, 2-1/4Cr-1Mo steel, and 300-series austenitic stainless steels. Dilution must be carefully controlled to avoid crack-sensitive deposit compositions. The technique used to produce the current filler metal compositions is aspiration-casting, i.e. drawing the liquid from the melt into glass rods. Future development efforts will involve fabrication of composite wires of similar compositions to permit mechanized gas tungsten arc (GTA) and/or gas metal arc (GMA) welding.

  10. Geolocation of a Known Altitude Target Using TDOA and GROA in the Presence of Receiver Location Uncertainty

    Directory of Open Access Journals (Sweden)

    Bing Deng

    2016-01-01

    Full Text Available This paper considers the problem of geolocating a target on the Earth surface using the target signal time difference of arrival (TDOA and gain ratio of arrival (GROA measurements when the receiver positions are subject to random errors. The geolocation Cramer-Rao lower bound (CRLB is derived and the performance improvement due to the use of target altitude information is quantified. An algebraic geolocation solution is developed and its approximate efficiency under small Gaussian noise is established analytically. Its sensitivity to the target altitude error is also studied. Simulations justify the validity of the theoretical developments and illustrate the good performance of the proposed geolocation method.

  11. VIIRS/NPP Moderate Resolution Terrain Corrected Geolocation 6-Min L1 Swath 750m Light V001

    Data.gov (United States)

    National Aeronautics and Space Administration — The Visible Infrared Imaging Radiometer Suite (VIIRS) Moderate Resolution Terrain Correction Geolocation (VNP03MODLL) Version 1 product from the Suomi National...

  12. Sentinel-1A/B Combined Product Geolocation Accuracy

    Directory of Open Access Journals (Sweden)

    Adrian Schubert

    2017-06-01

    Full Text Available Sentinel-1A and -1B are twin spaceborne synthetic aperture radar (SAR sensors developed and operated by the European Space Agency under the auspices of the Copernicus Earth observation programme. Launched in April 2014 and April 2016, Sentinel-1A and -1B are currently operating in tandem, in a common orbital configuration to provide an increased revisit frequency. In-orbit commissioning was completed for each unit within months of their respective launches, and level-1 SAR products generated by the operational SAR processor have been geometrically calibrated. In order to compare and monitor the geometric characteristics of the level-1 products from both units, as well as to investigate potential improvements, products from both satellites have been monitored since their respective commissioning phases. In this study, we present geolocation accuracy estimates for both Sentinel-1 units based on the time series of level-1 products collected thus far. While both units were demonstrated to be performing consistently, and providing SAR data products according to the nominal product specifications, a subtle beam- and mode-dependent azimuth bias common to the data from both units was identified. A method for removing the bias is proposed, and the corresponding improvement to the geometric accuracies is demonstrated and quantified.

  13. Impact of Improper Gaussian Signaling on the Achievable Rate of Overlay Cognitive Radio

    KAUST Repository

    Amin, Osama

    2017-05-12

    Improper Gaussian signaling (IGS) has been recently shown to provide performance improvements in underlay cognitive radio systems as opposed to the conventional proper Gaussian signaling (PGS) scheme. For the first time, this paper implements IGS scheme in overlay cognitive radio system, where the secondary transmitter broadcasts a mixture of two different signals. The first signal is selected from the PGS scheme to support the primary message transmission. On the other hand, the second signal is chosen to be from the IGS scheme in order to reduce the interference effect on the primary receiver. We then optimally design the overlay cognitive radio that employs IGS to maximize the secondary link achievable rate while satisfying the minimum rate requirement of the primary network. In particular, we derive closed form expressions for the circularity coefficient used in the IGS scheme and the power distribution parameters. Simulation results are provided to support our theoretical derivations.

  14. Automatic geolocation of targets tracked by aerial imaging platforms using satellite imagery

    Science.gov (United States)

    Shukla, P. K.; Goel, S.; Singh, P.; Lohani, B.

    2014-11-01

    Tracking of targets from aerial platforms is an important activity in several applications, especially surveillance. Knowled ge of geolocation of these targets adds additional significant and useful information to the application. This paper determines the geolocation of a target being tracked from an aerial platform using the technique of image registration. Current approaches utilize a POS to determine the location of the aerial platform and then use the same for geolocation of the targets using the principle of photogrammetry. The constraints of cost and low-payload restrict the applicability of this approach using UAV platforms. This paper proposes a methodology for determining the geolocation of a target tracked from an aerial platform in a partially GPS devoid environment. The method utilises automatic feature based registration technique of a georeferenced satellite image with an ae rial image which is already stored in UAV's database to retrieve the geolocation of the target. Since it is easier to register subsequent aerial images due to similar viewing parameters, the subsequent overlapping images are registered together sequentially thus resulting in the registration of each of the images with georeferenced satellite image thus leading to geolocation of the target under interest. Using the proposed approach, the target can be tracked in all the frames in which it is visible. The proposed concept is verified experimentally and the results are found satisfactory. Using the proposed method, a user can obtain location of target of interest as well features on ground without requiring any POS on-board the aerial platform. The proposed approach has applications in surveillance for target tracking, target geolocation as well as in disaster management projects like search and rescue operations.

  15. Solidification paths in modified Inconel 625 weld overlay material

    DEFF Research Database (Denmark)

    Chandrasekaran, Karthik; Tiedje, Niels Skat; Hald, John

    2009-01-01

    Inconel 625 is commonly used for overlay welding to protect the base metal against high temperature corrosion. The efficiency of corrosion protection depends on effective mixing of the overlay weld with the base metal and the subsequent segregation of alloy elements during solidification......, focus is put on how the composition of the dendrite core is affected by modifications to the alloy. It has previously been shown that when the overlay material corrodes, the corrosion take place in the dendrite core. Therefore, the discussion will be directed towards explaining the extent to which...

  16. Weld overlay cladding with iron aluminides

    Energy Technology Data Exchange (ETDEWEB)

    Goodwin, G.M. [Oak Ridge National Lab., TN (United States)

    1997-12-01

    The author has established a range of compositions for these alloys within which hot cracking resistance is very good, and within which cold cracking can be avoided in many instances by careful control of welding conditions, particularly preheat and postweld heat treatment. For example, crack-free butt welds have been produced for the first time in 12-mm thick wrought Fe{sub 3}Al plate. Cold cracking, however, still remains an issue in many cases. The author has developed a commercial source for composite weld filler metals spanning a wide range of achievable aluminum levels, and are pursuing the application of these filler metals in a variety of industrial environments. Welding techniques have been developed for both the gas tungsten arc and gas metal arc processes, and preliminary work has been done to utilize the wire arc process for coating of boiler tubes. Clad specimens have been prepared for environmental testing in-house, and a number of components have been modified and placed in service in operating kraft recovery boilers. In collaboration with a commercial producer of spiral weld overlay tubing, the author is attempting to utilize the new filler metals for this novel application.

  17. Mixed effects of geolocators on reproduction and survival of Cerulean Warblers, a canopy-dwelling, long-distance migrant

    Science.gov (United States)

    Douglas W. Raybuck; Jeffrey L. Larkin; Scott H. Stoleson; Than J. Boves

    2017-01-01

    Light-level geolocators, miniature devices used for tracking avian migration over the full annual cycle, are being widely deployed on small migratory passerines. However, the effects of carrying geolocators on the breeding biology of songbirds are unclear, and variable species- and guild-specific conclusions have been drawn regarding their effects on return rates (...

  18. nowCOAST's Map Service for Political Map Overlays

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Map Information: This nowCOAST map service provides map overlays depicting the boundaries of U.S. states, territories, counties and townships/county subdivisions,...

  19. Tests of HMA overlays using geosynthetics to reduce reflection cracking.

    Science.gov (United States)

    2009-12-01

    The primary objective of this field phase of the research project was to evaluate geosynthetic : products placed under or within hot mix asphalt overlays to reduce the severity or delay the appearance of : reflection cracks and to calibrate and valid...

  20. An Overlay Architecture for Throughput Optimal Multipath Routing

    Science.gov (United States)

    2017-01-14

    throughput optimal routing policy that has been studied for decades. Its strength lies in discovering multipath routes and utilizing them optimally... computing differential backlogs across the overlay edges, e.g. node 2 computes W 62,5 = Q 6 2 − Q 6 5 and W 6 2,6 = Q 6 2 − Q 6 6. Simulation results in...require the threshold computation and associated knowledge of the underlay topology. Overlay Backpressure (OBP): Redefine the differential backlog as, W

  1. Geospatial-temporal semantic graph representations of trajectories from remote sensing and geolocation data

    Science.gov (United States)

    Perkins, David Nikolaus; Brost, Randolph; Ray, Lawrence P.

    2017-08-08

    Various technologies for facilitating analysis of large remote sensing and geolocation datasets to identify features of interest are described herein. A search query can be submitted to a computing system that executes searches over a geospatial temporal semantic (GTS) graph to identify features of interest. The GTS graph comprises nodes corresponding to objects described in the remote sensing and geolocation datasets, and edges that indicate geospatial or temporal relationships between pairs of nodes in the nodes. Trajectory information is encoded in the GTS graph by the inclusion of movable nodes to facilitate searches for features of interest in the datasets relative to moving objects such as vehicles.

  2. Robust overlay metrology with differential Mueller matrix calculus.

    Science.gov (United States)

    Chen, Xiuguo; Gu, Honggang; Jiang, Hao; Zhang, Chuanwei; Liu, Shiyuan

    2017-04-17

    Overlay control is of vital importance to good device performances in semiconductor manufacturing. In this work, the differential Mueller matrix calculus is introduced to investigate the Mueller matrices of double-patterned gratings with overlay displacements, which helps to reveal six elementary optical properties hidden in the Mueller matrices. We find and demonstrate that, among these six elementary optical properties, the linear birefringence and dichroism, LB' and LD', along the ± 45° axes show a linear response to the overlay displacement and are zero when the overlay displacement is absent at any conical mounting. Although the elements from the two 2 × 2 off-diagonal blocks of the Mueller matrix have a similar property to LB' and LD', as reported in the literature, we demonstrate that it is only valid at a special conical mounting with the plane of incidence parallel to grating lines. The better property of LB' and LD' than the Mueller matrix elements of the off-diagonal blocks in the presence of overlay displacement verifies them to be a more robust indicator for the diffraction-based overlay metrology.

  3. Analyzing Forest Inventory Data from Geo-Located Photographs

    Science.gov (United States)

    Toivanen, Timo; Tergujeff, Renne; Andersson, Kaj; Molinier, Matthieu; Häme, Tuomas

    2015-04-01

    Forests are widely monitored using a variety of remote sensing data and techniques. Remote sensing offers benefits compared to traditional in-situ forest inventories made by experts. One of the main benefits is that the number of ground reference plots can be significantly reduced. Remote sensing of forests can provide reduced costs and time requirement compared to full forest inventories. The availability of ground reference data has been a bottleneck in remote sensing analysis over wide forested areas, as the acquisition of this data is an expensive and slow process. In this paper we present a tool for estimating forest inventory data from geo-located photographs. The tool can be used to estimate in-situ forest inventory data including estimated biomass, tree species, tree height and diameter. The collected in-situ forest measurements can be utilized as a ground reference material for spaceborne or airborne remote sensing data analysis. The GPS based location information with measured forest data makes it possible to introduce measurements easily as in-situ reference data. The central projection geometry of digital photographs allows the use of the relascope principle [1] to measure the basal area of stems per area unit, a variable very closely associated with tree biomass. Relascope is applied all over the world for forest inventory. Experiments with independent ground reference data have shown that in-situ data analysed from photographs can be utilised as reference data for satellite image analysis. The concept was validated by comparing mobile measurements with 54 independent ground reference plots from the Hyytiälä forest research station in Finland [2]. Citizen scientists could provide the manpower for analysing photographs from forests on a global level and support researchers working on tasks related to forests. This low-cost solution can also increase the coverage of forest management plans, particularly in regions where possibilities to invest on

  4. Device-correlated metrology for overlay measurements

    Science.gov (United States)

    Chen, Charlie; Huang, George K. C.; Pai, Yuan Chi; Wu, Jimmy C. H.; Cheng, Yu Wei; Hsu, Simon C. C.; Yu, Chun Chi; Amir, Nuriel; Choi, Dongsub; Itzkovich, Tal; Tarshish-Shapir, Inna; Tien, David C.; Huang, Eros; Kuo, Kelly T. L.; Kato, Takeshi; Inoue, Osamu; Kawada, Hiroki; Okagawa, Yutaka; Huang, Luis; Hsu, Matthew; Su, Amei

    2014-10-01

    One of the main issues with accuracy is the bias between the overlay (OVL) target and actual device OVL. In this study, we introduce the concept of device-correlated metrology (DCM), which is a systematic approach to quantify and overcome the bias between target-based OVL results and device OVL values. In order to systematically quantify the bias components between target and device, we introduce a new hybrid target integrating an optical OVL target with a device mimicking critical dimension scanning electron microscope (CD-SEM) target. The hybrid OVL target is designed to accurately represent the process influence on the actual device. In the general case, the CD-SEM can measure the bias between the target and device on the same layer after etch inspection (AEI) for all layers, the OVL between layers at AEI for most cases and after develop inspection for limited cases such as double-patterning layers. The results have shown that for the innovative process compatible hybrid targets the bias between the target and device is small, within the order of CD-SEM noise. Direct OVL measurements by CD-SEM show excellent correlation between CD-SEM and optical OVL measurements at certain conditions. This correlation helps verify the accuracy of the optical measurement results and is applicable for the imaging base OVL method using several target types advance imaging metrology, advance imaging metrology in die OVL, and the scatterometrybase OVL method. Future plans include broadening the hybrid target design to better mimic each layer process conditions such as pattern density. Additionally, for memory devices we are developing hybrid targets which enable other methods of accuracy verification.

  5. CLON: Overlay Networks and Gossip Protocols for Cloud Environments

    Science.gov (United States)

    Matos, Miguel; Sousa, António; Pereira, José; Oliveira, Rui; Deliot, Eric; Murray, Paul

    Although epidemic or gossip-based multicast is a robust and scalable approach to reliable data dissemination, its inherent redundancy results in high resource consumption on both links and nodes. This problem is aggravated in settings that have costlier or resource constrained links as happens in Cloud Computing infrastructures composed by several interconnected data centers across the globe.

  6. Accurate and efficient long-range lightning geo-location using a VLF radio atmospheric waveform bank

    Science.gov (United States)

    Said, Ryan Khalil

    2009-07-01

    On average there are ˜50 lightning flashes worldwide every second, with activity varying by region and season. Many systems currently exist that detect and locate lightning flashes for a broad range of commercial and scientific applications, including air traffic control, insurance claims, climate modeling, and the investigation of secondary atmospheric and magnetospheric electrical phenomena. These lightning detection systems have varying degrees of coverage area and location accuracy. Commercial ground-based systems that excel at locating return strokes in cloud-to-ground lightning use radio detection in the LF (30-300 kHz) band to provide very accurate location data, with a typical accuracy of ˜0.5 km, but they require a dense network of receivers separated by ˜400 km and are therefore primarily limited to monitoring the land areas within the network. In addition to radiating in the LF band, each lightning strike generates a broadband electromagnetic pulse containing frequencies from a few Hz through to the optical band with a peak component at VLF (3-30 kHz). Radio waves at VLF propagate through the waveguide formed by the Earth and the ionosphere with relatively low attenuation (˜3 dB per 1000 km), enabling the detection of these pulses, called radio atmospherics, at great distances from the lightning strike. Several existing networks utilize this efficient guiding to geo-locate lightning strikes often at distances greater than 5000 km from a given receiver. However, the Earth-ionosphere waveguide also presents a complex and time-varying channel that heavily disperses the pulse as it propagates away from the strike location. These networks fail to adequately address the path-dependence of the received impulse and suffer a lower location accuracy as a result (˜20 km). A new technique of long-range global lightning location is presented that both takes advantage of the efficient propagation at VLF and addresses the path-dependence of the propagation channel

  7. Analytical geolocation and three-dimensional localisation by time difference of arrival

    NARCIS (Netherlands)

    Naus, H.W.L.

    2016-01-01

    Geolocation based on time differences of arrival measured by three sensors is studied. Closed-form analytical solutions are derived, even for the cases where one or more sensors are not located on the earth. Exploiting four sensors, full three-dimensional localisation is achieved as well. These

  8. Non-Linear Optimization Applied to Angle-of-Arrival Satellite-Based Geolocation

    Science.gov (United States)

    2014-06-19

    the subject because it is expected to be the most challenging subject for geolocation. 15 An SV could be a dead satellite or space junk . These may be in...12 2.2 Space Vehicle Path . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 2.3 Triangulation Algorithm...39 3.1.2 Space Vehicle Generation . . . . . . . . . . . . . . . . . . . . . . 40 3.1.3 Satellite Generation

  9. Technique for Geolocation of EMI Emitters by O3B Satellites

    Science.gov (United States)

    2016-06-01

    electronic warfare GEO geosynchronous orbit GHz gigahertz GPS Global Positioning System HEO highly elliptical orbit HTS high throughput satellite Hz...altitude MEO medium Earth orbit SATCOM satellite communications SIGINT signals intelligence SMAD Space Mission Analysis and Design STK Systems Tool...having a basic understanding of satellite communications (SATCOM) and orbital mechanics, as the underlying concepts used in techniques for geolocation of

  10. Systematic analysis of geo-location and spectrum sensing as access methods to TV white space

    CSIR Research Space (South Africa)

    Mauwa, H

    2016-11-01

    Full Text Available in the literature have placed much emphasis on the limitations of the spectrum sensing approach and mainly based on the developed world environment ignoring the performance requirements of the geo-location database approach and how the absence of these requirements...

  11. FLightR: an r package for reconstructing animal paths from solar geolocation loggers

    NARCIS (Netherlands)

    Rakhimberdiev, E.; Saveliev, A.; Piersma, T.; Karagicheva, J.

    2017-01-01

    1. Solar geolocators are relatively cheap and simple tools which are widely used to study the migration of animals,especially birds. The methods to estimate the geographic positions from the light-intensity patterns collectedby these loggers, however, are still under development.2. The accurate

  12. OVERLAY DENTURES: A REVIEW AND REPORT OF FOUR CASES

    Directory of Open Access Journals (Sweden)

    Deeksha SHARMA

    2013-12-01

    Full Text Available Patients with ectodermal dysplasia or having under‑ gone cleft surgery with anodontia or hypodontia, hypo‑ plastic conical teeth and patients with severely worn dentition are difficult to treat because of the poor remaining tooth structure. These patients often exhibit loss of vertical dimension of occlusion and aesthetic problems and usually need complex prosthetic treatments. Financial constraints or other priorities often restrict one from choosing the most desirable treatment. The overlay removable denture is a covering prosthesis partially supported by natural teeth, tooth roots, or dental implants, providing an efficient alter‑ native of treatment. Clinical reports describe the various applications of overlay dentures.

  13. Measured residual stresses in overlay pipe weldments removed from service

    Energy Technology Data Exchange (ETDEWEB)

    Shack, W.J.

    1985-02-01

    Surface and throughwall residual stresses were measured on an elbow-to-pipe weldment that had been removed from the Hatch-2 reactor about a year after the application of a weld overlay. The results were compared with experimental measurements on three mock-up weldments and with finite-element calculations. The comparison shows that there are significant differences in the form and magnitude of the residual stress distributions. However, even after more than a year of service, the residual stresses over most of the inner surface of the actual plant weldment with an overlay were strongly compressive. 3 refs., 7 figs.

  14. Scopus and Web-of-Science 2012 compared in terms of aggregated journal-journal citation relations: Global maps and interactive overlays

    NARCIS (Netherlands)

    Leydesdorff, L.; de Moya-Anegón, F.; de Nooy, W.; Noyons, E.

    2014-01-01

    We compare the networks of aggregated journal-journal citation relations as provided by the Journal Citation Reports (JCR) 2012 of the Science and Social Science Citation Indexes (SCI and SSCI) with similar data for 2012 based on Scopus. First, we develop basemaps and overlays for the two sets

  15. Reproducing and Extending Real Testbed Evaluation of GeoNetworking Implementation in Simulated Networks

    OpenAIRE

    Tao, Ye; Tsukada, Manabu; LI, Xin; Kakiuchi, Masatoshi; Esaki, Hiroshi

    2016-01-01

    International audience; Vehicular Ad-hoc Network (VANET) is a type of Mobile Ad-hoc Network (MANET) which is specialized for vehicle communication. GeoNetworking is a new standardized network layer protocol for VANET which employs geolocation based routing. However, conducting large scale experiments in GeoNetworking softwares is extremely difficult, since it requires many extra factors such as vehicles, stuff, place, terrain, etc. In this paper, we propose a method to reproduce realistic res...

  16. VIIRS/NPP Imagery Resolution Terrain-Corrected Geolocation L1 6-Min Swath 375m NRT

    Data.gov (United States)

    National Aeronautics and Space Administration — The VNP03IMG, a Near Real Time (NRT) product, includes the geolocation fields that are calculated for each VIIRS imagery resolution band (I-band) Line of sight (LOS)...

  17. VIIRS/NPP Moderate Resolution Terrain-Corrected Geolocation L1 6-Min Swath 750m NRT

    Data.gov (United States)

    National Aeronautics and Space Administration — The VNP03MOD_NRT, a Near Real Time (NRT) product, includes the geolocation fields that are calculated for each VIIRS moderate resolution band (M-band) Line of sight...

  18. MODIS/Terra Near Real Time (NRT) Geolocation Angles Daily L2G Global 1km SIN Grid Day

    Data.gov (United States)

    National Aeronautics and Space Administration — The MODIS Near Real Time (NRT) Global Geolocation Angle (MODMGGAD) files contain information on solar illumination and instrument viewing geometry angles. These data...

  19. MODIS/Aqua Near Real Time (NRT) Geolocation Angles Daily L2G Global 1km SIN Grid Day

    Data.gov (United States)

    National Aeronautics and Space Administration — The MODIS Near Real Time (NRT) Global Geolocation Angle (MODMGGAD) files contain information on solar illumination and instrument viewing geometry angles. These data...

  20. IceBridge CMG GT-1A Gravimeter L2 Geolocated Free Air Gravity Disturbances V001

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set contains geolocated free air gravity disturbances derived from measurements taken over Antarctica using the GT-1A gravity meter S-019. The data were...

  1. Mapping (USPTO) patent data using overlays to Google Maps

    NARCIS (Netherlands)

    Leydesdorff, L.; Bornmann, L.

    2012-01-01

    A technique is developed using patent information available online (at the U.S. Patent and Trademark Office) for the generation of Google Maps. The overlays indicate both the quantity and the quality of patents at the city level. This information is relevant for research questions in technology

  2. Continued implementation of high performance thin overlays in Texas districts.

    Science.gov (United States)

    2017-06-22

    As part of Research Project 0-5598, outputs include guidelines and specifications on how a district can design and construct long-life overlays using the concept of balanced mix design; and training materials describing the best ways to select, desig...

  3. Nullspace MUSIC and Improved Radio Frequency Emitter Geolocation from a Mobile Antenna Array

    Science.gov (United States)

    Kintz, Andrew L.

    This work advances state-of-the-art Radio Frequency (RF) emitter geolocation from an airborne or spaceborne antenna array. With an antenna array, geolocation is based on Direction of Arrival (DOA) estimation algorithms such as MUSIC. The MUSIC algorithm applies to arbitrary arrays of polarization sensitive antennas and yields high resolution. However, MUSIC fails to obtain its theoretical resolution for simultaneous, closely spaced, co-frequency signals. We propose the novel Nullspace MUSIC algorithm, which outperforms MUSIC and its existing modifications while maintaining MUSIC(apostrophe)s fundamental orthogonality test. Nullspace MUSIC applies a divide-and-conquer approach and estimates a single DOA at a time. Additionally, an antenna array on an aircraft cannot be perfectly calibrated. RF waves are blocked, reflected, and scattered in a time-varying fashion by the platform around the antenna array. Consequently, full-wave electromagnetics simulations or demanding measurements of the entire platform cannot eliminate the mismatch between the true, in-situ antenna patterns and the antenna patterns that are available for DOA estimation (the antenna array manifold). Platform-induced manifold mismatch severely degrades MUSIC(apostrophe)s resolution and accuracy. We show that Nullspace MUSIC improves DOA accuracy for well separated signals that are incident on an airborne antenna array. Conventionally, geolocation from a mobile platform draws Lines of Bearing (LOB) from the antenna array along the DOAs to find the locations where the DOAs intersect with the ground. However, averaging the LOBs in the global coordinate system yields large errors due to geometric dilution of precision. Since averaging positions fails, a single emitter is typically located by finding the position on the ground that yields the Minimum Apparent Angular Error (MAAE) for the DOA estimates over a flight. We extend the MAAE approach to cluster LOBs from multiple emitters. MAAE clustering

  4. Experimental Simulation-Based Performance Evaluation of an SMS-Based Emergency Geolocation Notification System.

    Science.gov (United States)

    Osebor, Isibor; Misra, Sanjay; Omoregbe, Nicholas; Adewumi, Adewole; Fernandez-Sanz, Luis

    2017-01-01

    In an emergency, a prompt response can save the lives of victims. This statement generates an imperative issue in emergency medical services (EMS). Designing a system that brings simplicity in locating emergency scenes is a step towards improving response time. This paper therefore implemented and evaluated the performance of an SMS-based emergency geolocation notification system with emphasis on its SMS delivery time and the system's geolocation and dispatch time. Using the RAS metrics recommended by IEEE for evaluation, the designed system was found to be efficient and effective as its reliability stood within 62.7% to 70.0% while its availability stood at 99% with a downtime of 3.65 days/year.

  5. Experimental Simulation-Based Performance Evaluation of an SMS-Based Emergency Geolocation Notification System

    Directory of Open Access Journals (Sweden)

    Isibor Osebor

    2017-01-01

    Full Text Available In an emergency, a prompt response can save the lives of victims. This statement generates an imperative issue in emergency medical services (EMS. Designing a system that brings simplicity in locating emergency scenes is a step towards improving response time. This paper therefore implemented and evaluated the performance of an SMS-based emergency geolocation notification system with emphasis on its SMS delivery time and the system’s geolocation and dispatch time. Using the RAS metrics recommended by IEEE for evaluation, the designed system was found to be efficient and effective as its reliability stood within 62.7% to 70.0% while its availability stood at 99% with a downtime of 3.65 days/year.

  6. Visualization of Disciplinary Profiles: Enhanced Science Overlay Maps

    Directory of Open Access Journals (Sweden)

    Stephen Carley

    2017-08-01

    Full Text Available Purpose: The purpose of this study is to modernize previous work on science overlay maps by updating the underlying citation matrix, generating new clusters of scientific disciplines, enhancing visualizations, and providing more accessible means for analysts to generate their own maps. Design/methodology/approach: We use the combined set of 2015 Journal Citation Reports for the Science Citation Index (n of journals = 8,778 and the Social Sciences Citation Index (n = 3,212 for a total of 11,365 journals. The set of Web of Science Categories in the Science Citation Index and the Social Sciences Citation Index increased from 224 in 2010 to 227 in 2015. Using dedicated software, a matrix of 227 × 227 cells is generated on the basis of whole-number citation counting. We normalize this matrix using the cosine function. We first develop the citing-side, cosine-normalized map using 2015 data and VOSviewer visualization with default parameter values. A routine for making overlays on the basis of the map (“wc15.exe” is available at http://www.leydesdorff.net/wc15/index.htm. Findings: Findings appear in the form of visuals throughout the manuscript. In Figures 1–9 we provide basemaps of science and science overlay maps for a number of companies, universities, and technologies. Research limitations: As Web of Science Categories change and/or are updated so is the need to update the routine we provide. Also, to apply the routine we provide users need access to the Web of Science. Practical implications: Visualization of science overlay maps is now more accurate and true to the 2015 Journal Citation Reports than was the case with the previous version of the routine advanced in our paper. Originality/value: The routine we advance allows users to visualize science overlay maps in VOSviewer using data from more recent Journal Citation Reports.

  7. On the Design of Energy Efficient Optical Networks with Software Defined Networking Control Across Core and Access Networks

    DEFF Research Database (Denmark)

    Wang, Jiayuan; Yan, Ying; Dittmann, Lars

    2013-01-01

    This paper presents a Software Defined Networking (SDN) control plane based on an overlay GMPLS control model. The SDN control platform manages optical core networks (WDM/DWDM networks) and the associated access networks (GPON networks), which makes it possible to gather global information...

  8. Application of Interfacial Propagation and Kinking Crack Concept to ECC/Concrete Overlay Repair System

    Directory of Open Access Journals (Sweden)

    Yaw ChiaHwan

    2014-01-01

    Full Text Available Research on the application of ultraductile engineered cementitious composite (ECC as overlay in the repair of deteriorated concrete structures is performed in this paper. Also, interfacial crack kinking and trapping mechanism experimentally observed in ECC/concrete overlay repair system are described by comparison of toughness and energy release rate. The mechanism involves cycles of extension, kinking, and arrest of interfacial crack into the overlay. Experimental testing of overlay repair system reveals significant improvements in load carrying capacity and ductility over conventional concrete overlay. The commonly observed overlay system failure mode of delamination or spalling is eliminated when ECC is applied. These failure modes are suppressed when ECC is used as an ideal and durable candidate overlay repair material.

  9. Complexity Leadership Theory: A United States Marine Corps Historical Overlay

    Science.gov (United States)

    2017-05-25

    the concept of the Young Turks became an important and frequently replicated, informal small innovation group in the Marine Corps. In another...globalized environment, leading transformational innovation has become more complex and dynamic. Complexity Leadership Theory (CLT) attempts to reconcile...information age organizations. This monograph overlays CLT on two periods of significant warfare innovation in the Marine Corps to evaluate the role of

  10. Perceived effects of coloured overlays on reading material in persons with albinism

    Directory of Open Access Journals (Sweden)

    N. T. Makgaba

    2008-01-01

    Full Text Available Persons with albinism often complain of glare when reading. They may therefore benefit from coloured filter overlays just as they benefit from tinted lenses. The purpose of this study was to assess the effectof coloured overlays on print perception in persons with oculocutaneous albinism (OCA.   Fifty subjects were included in this study, their ages ranged from 12 to 31 years with a mean of 16.12 years (SD = ± 4.56 years.  Following refraction and subsequent compensation for refractive errors, subjective perception of print was examined with the subject looking at the Wilkins® reading rate test chart with and without colored filter overlay/s.  The subjects were asked to respond to questions previously used in a questionnaire by Wilkins (2001. The percentage frequencies of positive (beneficial responses were used to decide whether or not a particular overlay would enhance reading performance.  McNemar’s test was used to establish significant differences between responses to questions without and with overlays. All single overlays gave greater percentages of positive responses (92.0-97.2% than without overlay (85.2%.  The single overlay that provided the highest positive responses was blue (97.2% and the least was purple (92.0%. All double overlays, except grey/grey (82.0% gave greater positive responses than without overlay (85.2%. Aqua/blue gave the greatest positive responses (possible benefits (97.2%, followed by rose/rose (96.8%.  Comparing the responses without overlay with single and double overlays, the difference in responses to the five questions was only significant (p < 0.05 with regard to brightness of the surface. The results suggest that overlays provided a more glare-free reading surface than without an overlay. It was, therefore concluded that the best advantage of the coloured overlays was in glare reduction.  Although this study showed that there were more subjects who preferred single blue and aqua/blue double

  11. Ground truth data generation for skull-face overlay.

    Science.gov (United States)

    Ibáñez, O; Cavalli, F; Campomanes-Álvarez, B R; Campomanes-Álvarez, C; Valsecchi, A; Huete, M I

    2015-05-01

    Objective and unbiased validation studies over a significant number of cases are required to get a more solid picture on craniofacial superimposition reliability. It will not be possible to compare the performance of existing and upcoming methods for craniofacial superimposition without a common forensic database available for the research community. Skull-face overlay is a key task within craniofacial superimposition that has a direct influence on the subsequent task devoted to evaluate the skull-face relationships. In this work, we present the procedure to create for the first time such a dataset. We have also created a database with 19 skull-face overlay cases for which we are trying to overcome legal issues that allow us to make it public. The quantitative analysis made in the segmentation and registration stages, together with the visual assessment of the 19 face-to-face overlays, allows us to conclude that the results can be considered as a gold standard. With such a ground truth dataset, a new horizon is opened for the development of new automatic methods whose performance could be now objectively measured and compared against previous and future proposals. Additionally, other uses are expected to be explored to better understand the visual evaluation process of craniofacial relationships in craniofacial identification. It could be very useful also as a starting point for further studies on the prediction of the resulting facial morphology after corrective or reconstructive interventionism in maxillofacial surgery.

  12. The Development of An Analytical Overlay Design Procedure

    Directory of Open Access Journals (Sweden)

    Djunaedi Kosasih

    2008-01-01

    Full Text Available Pavement structural evaluation using pavement modulus values resulting from back calculation process on non-destructive deflection data has been adopted to quantify objectively the conditions of existing pavements under various traffic loading and environmental conditions. However, such an advanced technique is not yet followed widely by advances in analytical overlay design procedures. One possible reason is perhaps due to its requirement to perform complex computations. A new module of computer program BackCalc has been developed to do that task based on the allowable maximum deflection criterion specified by the Asphalt Institute’83. The rationale is that adequate overlay thickness will be computed by iteration to result in theoretical maximum deflection that closely matches against the specified allowable maximum deflection. This paper outlines the major components of the program module illustrated by using a practical example. The overlay thickness obtained was found to be comparable with that of the known AASHTO’93 method

  13. PEMODELAN PROTOTYPE TRACKING DENGAN PEMANFAATAN GEOLOCATION SEBAGAI GPS (GLOBAL POSITIONING SYSTEM BERBASIS WEB MOBILE PADA JASA PENGIRIMAN JNE SEMARANG

    Directory of Open Access Journals (Sweden)

    Ika Tri Meilani

    2016-03-01

    Full Text Available JNE merupakan perusahaan yang bergerak dibidang pengiriman barang atau dokumen yang sangat maju, karena banyak dimanfaatkan berbagai toko online dalam melakukan pengiriman barang pada customer. Sementara itu, tingkat kejahatan dijalanan semakin meningkat di berbagai kota di Indonesia. Sehingga diperlukan antisipasi pengamanan pada sebuah pengiriman untuk meningkatkan kepercayaan customer dan memberi rasa aman pada bagian pengangkutan. Selain dari sisi pengamanan, tingkat efisiensi waktu dalam pengiriman dapat berpengaruh pada tingkat kinerja perusahaan. Maka diperlukan sebuah sistem yang mampu memonitoring pengangkutan dan melakukan estimasi waktu secara efisien dalam membatasi waktu pengiriman dengan memanfaatkan geolocation sebagai GPS dengan menggunakan metode prototype model. Maka dapat diambil kesimpulan bahwa Pemodelan Prototype Tracking dengan Pemanfaat Geolocation sebagai GPS dapat dimanfaatkan sebagai media dalam memonitor pengiriman barang secara visual (Map. Kata Kunci : Tracking, Jasa Pengiriman, Geolocation, Google Map, GPS.

  14. Effects of geolocators on hatching success, return rates, breeding movements, and change in body mass in 16 species of Arctic-breeding shorebirds

    NARCIS (Netherlands)

    Weiser, Emily L; Lanctot, Richard B.; Brown, Stephen C; Alves, José A.; Battley, Phil; Bentzen, Rebecca; Bêty, Joël; Bishop, Mary Anne; Boldenow, Megan; Bollache, Loïc; Casler, Bruce; Christie, Maureen; T. Coleman, Jonathan; Conklin, Jesse; B. English, Willow; Gates, H. River; Gilg, Olivier; Giroux, Marie-Andrée; Gosbell, Ken; Hassell, Chris J.; Helmericks, Jim; Johnson, Andrew; Katrínardóttir, Borgný; Koivula, Kari; Kwon, Eunbi; Lamarre, Jean-Francois; Lang, Johannes; Lank, David B.; Lecomte, Nicolas; Liebezeit, Joe; Loverti, Vanessa; McKinnon, Laura; Minton, Clive D. T.; Mizrahi, David; Minton, Clive D. T.; Nol, Erica; Pakanen, Veli-Matti; Perz, Johanna; Porter, Ron; Rausch, Jennie; Reneerkens, Jeroen; Rönkä, Nelli; Saalfeld, Sarah; Senner, Nathan; Sittler, Benoit; Smith, Paul A.; Sowl, Kristine; Taylor, Audrey; Ward, David H.; Yezerinac, Stephen; Sandercock, Brett K.

    2016-01-01

    Background: Geolocators are useful for tracking movements of long-distance migrants, but potential negative effects on birds have not been well studied. We tested for effects of geolocators (0.8–2.0 g total, representing 0.1–3.9 % of mean body mass) on 16 species of migratory shorebirds, including

  15. Year-round tracking of small trans-Saharan migrants using light-level geolocators.

    Directory of Open Access Journals (Sweden)

    Erich Bächler

    Full Text Available Since 1899 ringing (or banding remained the most important source of information about migration routes, stopover sites and wintering grounds for birds that are too small to carry satellite-based tracking systems. Despite the large quantity of migrating birds ringed in their breeding areas in Europe, the number of ring recoveries from sub-Saharan Africa is very low and therefore the whereabouts of most small bird species outside the breeding season remain a mystery. With new miniaturized light-level geolocators it is now possible to look beyond the limits of ring recovery data. Here we show for the first time year round tracks of a near passerine trans-Saharan migrant, the European Hoopoe (Upupa epops epops. Three birds wintered in the Sahel zone of Western Africa where they remained stationary for most of the time. One bird chose a south-easterly route following the Italian peninsula. Birds from the same breeding population used different migration routes and wintering sites, suggesting a low level of migratory connectivity between breeding and wintering areas. Our tracking of a near passerine bird, the European Hoopoe, with light-level geolocators opens a new chapter in the research of Palaearctic-African bird migration as this new tool revolutionizes our ability to discover migration routes, stopover sites and wintering grounds of small birds.

  16. Year-round tracking of small trans-Saharan migrants using light-level geolocators.

    Science.gov (United States)

    Bächler, Erich; Hahn, Steffen; Schaub, Michael; Arlettaz, Raphaël; Jenni, Lukas; Fox, James W; Afanasyev, Vsevolod; Liechti, Felix

    2010-03-05

    Since 1899 ringing (or banding) remained the most important source of information about migration routes, stopover sites and wintering grounds for birds that are too small to carry satellite-based tracking systems. Despite the large quantity of migrating birds ringed in their breeding areas in Europe, the number of ring recoveries from sub-Saharan Africa is very low and therefore the whereabouts of most small bird species outside the breeding season remain a mystery. With new miniaturized light-level geolocators it is now possible to look beyond the limits of ring recovery data. Here we show for the first time year round tracks of a near passerine trans-Saharan migrant, the European Hoopoe (Upupa epops epops). Three birds wintered in the Sahel zone of Western Africa where they remained stationary for most of the time. One bird chose a south-easterly route following the Italian peninsula. Birds from the same breeding population used different migration routes and wintering sites, suggesting a low level of migratory connectivity between breeding and wintering areas. Our tracking of a near passerine bird, the European Hoopoe, with light-level geolocators opens a new chapter in the research of Palaearctic-African bird migration as this new tool revolutionizes our ability to discover migration routes, stopover sites and wintering grounds of small birds.

  17. Ductile film delamination from compliant substrates using hard overlayers

    Science.gov (United States)

    Cordill, M.J.; Marx, V.M.; Kirchlechner, C.

    2014-01-01

    Flexible electronic devices call for copper and gold metal films to adhere well to polymer substrates. Measuring the interfacial adhesion of these material systems is often challenging, requiring the formulation of different techniques and models. Presented here is a strategy to induce well defined areas of delamination to measure the adhesion of copper films on polyimide substrates. The technique utilizes a stressed overlayer and tensile straining to cause buckle formation. The described method allows one to examine the effects of thin adhesion layers used to improve the adhesion of flexible systems. PMID:25641995

  18. Opportunistic transmitter selection for selfless overlay cognitive radios

    KAUST Repository

    Shaqfeh, Mohammad

    2013-11-01

    We propose an opportunistic strategy to grant channel access to the primary and secondary transmitters in causal selfless overlay cognitive radios over block-fading channels. The secondary transmitter helps the primary transmitter by relaying the primary messages opportunistically, aided by a buffer to store the primary messages temporarily. The optimal channel-aware transmitter- selection strategy is the solution of the maximization of the average secondary rate under the average primary rate requirement and the buffer stability constraints. Numerical results demonstrate the gains of the proposed opportunistic selection strategy. © 2013 IEEE.

  19. The Effects of Cognitive Jamming on Wireless Sensor Networks Used for Geolocation

    Science.gov (United States)

    2012-03-01

    With the increase of location based services (e.g. cell phones and Facebook Check In service) comes the increased dependence on this tech- nology. The...The first eight digits are always 0014.4F01. The last eight digits are device dependent and printed on a sticker visible through the translucent...plastic on the radio antenna fin. A typical sticker would show something like 0000.77AE, implying an IEEE address for that SPOT of 0014.4F01.0000.77AE [24

  20. Examination of overlay pipe weldments removed from the Hatch-2 reactor

    Energy Technology Data Exchange (ETDEWEB)

    Park, J.Y.; Kupperman, D.S.; Shack, W.J.

    1985-02-01

    Laboratory ultrasonic examination (UT), dye penetrant examination (PT), metallography, and sensitization measurements were performed on Type 304 stainless steel overlay pipe weldments from the Hatch-2 BWR to determine the effectiveness of UT through overlays and the effects of the overlays on crack propagation in the weldments. Little correlation was observed between the results of earlier in-service ultrasonic inspection and the results of PT and destructive examination. Considerable difficulty was encountered in correctly detecting the presence of cracks by UT in the laboratory. Blunting of the crack tip by the weld overlay was observed, but there was no evidence of tearing or throughwall extension of the crack beyond the blunted region.

  1. Beyond Space For Spatial Networks

    CERN Document Server

    Expert, Paul; Blondel, Vincent D; Lambiotte, Renaud

    2010-01-01

    Many complex systems are organized in the form of a network embedded in space. Important examples include the physical Internet infrastucture, road networks, flight connections, brain functional networks and social networks. The effect of space on network topology has recently come under the spotlight because of the emergence of pervasive technologies based on geo-localization, which constantly fill databases with people's movements and thus reveal their trajectories and spatial behaviour. Extracting patterns and regularities from the resulting massive amount of human mobility data requires the development of appropriate tools for uncovering information in spatially-embedded networks. In contrast with most works that tend to apply standard network metrics to any type of network, we argue in this paper for a careful treatment of the constraints imposed by space on network topology. In particular, we focus on the problem of community detection and propose a modularity function adapted to spatial networks. We sh...

  2. Annual cycle and migration strategies of a trans-Saharan migratory songbird : A geolocator study in the great reed warbler

    NARCIS (Netherlands)

    Lemke, Hilger W.; Tarka, Maja; Klaassen, Raymond H. G.; Akesson, Mikael; Bensch, Staffan; Hasselquist, Dennis; Hansson, Bengt

    2013-01-01

    Recent technological advancements now allow us to obtain geographical position data for a wide range of animal movements. Here we used light-level geolocators to study the annual migration cycle in great reed warblers (Acrocephalus arundinaceus), a passerine bird breeding in Eurasia and wintering in

  3. A hidden Markov model for reconstructing animal paths from solar geolocation loggers using templates for light intensity

    NARCIS (Netherlands)

    Rakhimberdiev, Eldar; Winkler, David W; Bridge, Eli; Seavy, Nathaniel E; Sheldon, Daniel; Piersma, Theunis; Saveliev, Anatoly

    2015-01-01

    BACKGROUND: Solar archival tags (henceforth called geolocators) are tracking devices deployed on animals to reconstruct their long-distance movements on the basis of locations inferred post hoc with reference to the geographical and seasonal variations in the timing and speeds of sunrise and sunset.

  4. A hidden Markov model for reconstructing animal paths from solar geolocation loggers using templates for light intensity

    NARCIS (Netherlands)

    Rakhimberdiev, E.; Winkler, D.W.; Bridge, E.; Seavy, N.E.; Sheldon, D.; Piersma, T.; Saveliev, A.

    2015-01-01

    Background: Solar archival tags (henceforth called geolocators) are tracking devices deployed on animals to reconstructtheir long-distance movements on the basis of locations inferred post hoc with reference to the geographical andseasonal variations in the timing and speeds of sunrise and sunset.

  5. COMMUNICATION: Multielectrode arrays with elastomeric microstructured overlays for extracellular recordings from patterned neurons

    Science.gov (United States)

    Claverol-Tinturé, E.; Ghirardi, M.; Fiumara, F.; Rosell, X.; Cabestany, J.

    2005-06-01

    Multielectrode array technology constitutes a promising approach for the characterization of the activity-dependent neuronal plasticity underlying information processing in the nervous system. For this purpose, long-term monitoring and stimulation of cultured neuronal networks with one-to-one neuron-sensor interfacing is advantageous. Existing neurochips that meet these specifications have made use of custom 3D structures requiring clean-room intensive microfabrication techniques. Low-cost fabrication procedures with potential for mass production would facilitate progress in the area. To this end, we have developed a sandwich structure comprising an elastomeric film, microstructured by replica moulding and microhole punching, for neuronal patterning, and a standard planar microelectrode array (MEA), for stimulation and recording. The elastomeric film includes microwells for cell body confinement, and microchannels capable of guiding neurites for network topology specification. The device is formed by overlaying the elastomeric structures on planar arrays. The combination of replica moulding, rapid prototyping and planar MEAs results in low-cost neurochips accessible to most neurophysiology labs. Single neuron patterning and recordings of extracellular potentials are demonstrated.

  6. Trends in Development of Weld Overlaying During The 21ST Century

    Directory of Open Access Journals (Sweden)

    Nikolov Mitko

    2014-08-01

    Full Text Available The present article discusses the trends in the development of welding and weld overlaying on the threshold of the new millennium and during it. It presents the trends in the production of welding materials for welding and weld overlaying in industrially developed and developing countries. The structure of welding methods is also shown, giving priority to its development until 2020.

  7. The use of fiber reinforcement in latex modified concrete overlay : final report.

    Science.gov (United States)

    2016-12-01

    The requirement to quickly reopen highways in North Carolina has motivated the increased use of rapid-setting concrete in overlays. The addition of polymer latex to the material has been used to increase the service life of the overlays. The latex mo...

  8. Towards Autonomous Modular UAV Missions: The Detection, Geo-Location and Landing Paradigm.

    Science.gov (United States)

    Kyristsis, Sarantis; Antonopoulos, Angelos; Chanialakis, Theofilos; Stefanakis, Emmanouel; Linardos, Christos; Tripolitsiotis, Achilles; Partsinevelos, Panagiotis

    2016-11-03

    Nowadays, various unmanned aerial vehicle (UAV) applications become increasingly demanding since they require real-time, autonomous and intelligent functions. Towards this end, in the present study, a fully autonomous UAV scenario is implemented, including the tasks of area scanning, target recognition, geo-location, monitoring, following and finally landing on a high speed moving platform. The underlying methodology includes AprilTag target identification through Graphics Processing Unit (GPU) parallelized processing, image processing and several optimized locations and approach algorithms employing gimbal movement, Global Navigation Satellite System (GNSS) readings and UAV navigation. For the experimentation, a commercial and a custom made quad-copter prototype were used, portraying a high and a low-computational embedded platform alternative. Among the successful targeting and follow procedures, it is shown that the landing approach can be successfully performed even under high platform speeds.

  9. Geo-Located Tweets. Enhancing Mobility Maps and Capturing Cross-Border Movement.

    Directory of Open Access Journals (Sweden)

    Justine I Blanford

    Full Text Available Capturing human movement patterns across political borders is difficult and this difficulty highlights the need to investigate alternative data streams. With the advent of smart phones and the ability to attach accurate coordinates to Twitter messages, users leave a geographic digital footprint of their movement when posting tweets. In this study we analyzed 10 months of geo-located tweets for Kenya and were able to capture movement of people at different temporal (daily to periodic and spatial (local, national to international scales. We were also able to capture both long and short distances travelled, highlighting regional connections and cross-border movement between Kenya and the surrounding countries. The findings from this study has broad implications for studying movement patterns and mapping inter/intra-region movement dynamics.

  10. Towards Autonomous Modular UAV Missions: The Detection, Geo-Location and Landing Paradigm

    Directory of Open Access Journals (Sweden)

    Sarantis Kyristsis

    2016-11-01

    Full Text Available Nowadays, various unmanned aerial vehicle (UAV applications become increasingly demanding since they require real-time, autonomous and intelligent functions. Towards this end, in the present study, a fully autonomous UAV scenario is implemented, including the tasks of area scanning, target recognition, geo-location, monitoring, following and finally landing on a high speed moving platform. The underlying methodology includes AprilTag target identification through Graphics Processing Unit (GPU parallelized processing, image processing and several optimized locations and approach algorithms employing gimbal movement, Global Navigation Satellite System (GNSS readings and UAV navigation. For the experimentation, a commercial and a custom made quad-copter prototype were used, portraying a high and a low-computational embedded platform alternative. Among the successful targeting and follow procedures, it is shown that the landing approach can be successfully performed even under high platform speeds.

  11. A Robust Routing Strategy for Density Spanner based Wireless Ad Hoc Networks

    OpenAIRE

    Divi Mydhili1; K.R.R.Mohana Rao2

    2012-01-01

    An important problem for wireless ad hoc networks has been to design overlay networks that allow time- and energy-efficient routing. Many local-control strategies for maintaining such overlay networks have already been suggested, but most of them are based on an oversimplified wireless communication model. We address cooperative caching in wireless networks, where the nodes may be mobile and exchange information in a peer-to-peer fashion. We consider both cases of nodes with large and small-s...

  12. Effect of PCC Joint Skew on Reflective Cracking in HMA Overlays

    CERN Document Server

    Ghauch, By Ziad G

    2011-01-01

    Reflective cracking is a relatively premature distress that occurs in HMA materials overlaying cracked and jointed underlying pavements. The high concentration of stresses and strains in the vicinity of the discontinuity of the old pavement causes the cracks to reflect into the newly placed HMA overlay. While it is a common practice to use skewed transverse joints in rigid pavements to improve the latter's performance, the impact of such a practice on the cracking of a potential HMA overlay has not been examined so far. In this context, this study investigates the effect of using skewed transverse joints in rigid pavements on reflective cracking development in the HMA overlay. Advanced three-dimensional Finite Element models including viscoelastic material properties for the HMA overlay, 3D beam modeling of dowel bars, non-uniform tire-pavement contact stresses, friction interfaces, and infinite boundary elements were constructed for both normal and skewed transverse joints using ABAQUS v-6.11. The potential ...

  13. Strain Response of Hot-Mix Asphalt Overlays for Bottom-Up Reflective Cracking

    CERN Document Server

    Ghauch, Ziad G

    2011-01-01

    This paper examines the strain response of typical HMA overlays above jointed PCC slabs prone to bottom-up reflective cracking. The occurrence of reflective cracking under the combined effect of traffic and environmental loading significantly reduces the design life of the HMA overlays and can lead to its premature failure. In this context, viscoelastic material properties combined with cyclic vehicle loadings and pavement temperature distribution were implemented in a series of FE models in order to study the evolution of horizontal tensile and shear strains at the bottom of the HMA overlay. The effect of several design parameters, such as subbase and subgrade moduli, vehicle speed, overlay thickness, and temperature condition, on the horizontal and shear strain response was investigated. Results obtained show that the rate of horizontal and shear strain increase at the bottom of the HMA overlay drop with higher vehicle speed, higher subgrade modulus, and higher subbase modulus. Moreover, the rate of horizon...

  14. Axial compression behavior of concrete masonry wallettes strengthened with cement mortar overlays

    Directory of Open Access Journals (Sweden)

    F. L. De Oliveira

    Full Text Available This paper presents the results of a series of axial compression tests on concrete block wallettes coated with cement mortar overlays. Different types of mortars and combinations with steel welded meshes and fibers were tested. The experimental results were discussed based on different theoretical approaches: analytical and Finite Element Method models. The main conclusions are: a the application of mortar overlays increases the wall strength, but not in a uniform manner; b the strengthening efficiency of wallettes loaded in axial compression is not proportional to the overlay mortar strength because it can be affected by the failure mechanisms of the wall; c steel mesh reinforced overlays in combination with high strength mortar show better efficiency, because the steel mesh mitigates the damage effects in the block wall and in the overlays themselves; d simplified theoretical methods of analysis as described in this paper can give satisfactory predictions of masonry wall behavior up to a certain level.

  15. Hybrid image potential states in molecular overlayers on graphene

    Science.gov (United States)

    Wella, Sasfan Arman; Sawada, Hiroyuki; Kawaguchi, Nana; Muttaqien, Fahdzi; Inagaki, Kouji; Hamada, Ikutaro; Morikawa, Yoshitada; Hamamoto, Yuji

    2017-11-01

    The structural and electronic properties of naphthalene adsorbed on graphene are studied from first principles using the van der Waals density functional method. It is shown that naphthalene molecules are stabilized by forming a superstructure with the periodicity of (2 √{3 }×2 √{3 }) and a tilted molecular adsorption geometry on graphene, in good agreement with the scanning tunneling microscopy (STM) experiments on highly oriented pyrolytic graphite. Our results predict that image potential states (IPSs) are induced by intermolecular interaction on the naphthalene overlayer, hybridizing with the IPSs derived from graphene. The resultant hybrid IPSs are characterized by anisotropic effective mass reflecting the molecular structure of naphthalene. By means of STM simulations, we reveal that one of the hybrid IPSs manifests itself as an oval protrusion distinguishable from naphthalene molecular orbitals, which identifies the origin of an experimental STM image previously attributed to the lowest unoccupied molecular orbital of naphthalene.

  16. Low-energy photoelectron transmission through aerosol overlayers

    Science.gov (United States)

    Amanatidis, Stavros; Yoder, Bruce L.; Signorell, Ruth

    2017-06-01

    The transmission of low-energy (squalane, squalene, and di-ethyl-hexyl-sebacate shells. The photoelectrons are exclusively formed in the core of the particles by two-photon ionization. The total photoelectron yield recorded as a function of shell thicknesses (1-80 nm) shows a bi-exponential attenuation. For all substances, the damping parameter for shell thicknesses below 15 nm lies around 8 to 9 nm and is tentatively assigned to the electron attenuation length at electron kinetic energies of ≲1 eV. The significantly larger damping parameters for thick shells (>20 nm) are presumably a consequence of distorted core-shell structures. A first comparison of aerosol and traditional thin film overlayer methods is provided.

  17. Application of DBM system to overlay verification and wiggling quantification for advanced process

    Science.gov (United States)

    Lee, Taehyeong; Kim, Jungchan; Yoo, Gyun; Park, Chanha; Yang, Hyunjo; Yim, Donggyu; Park, Byoungjun; Maruyama, Kotaro; Yamamoto, Masahiro

    2012-03-01

    With the shrinkage of semiconductor device scales, advanced semiconductor industries face tremendous challenges in process control. As lithography and etch processes are pushed to get smaller dimensions, the overlay and wiggling control are hot issues due to the limiting of pattern performance. Many chip makers are using Double Patterning Technology (DPT) process to overcome design rule limitations but they are also concerned about overlay control. In DPT process, obtaining accurate overlay data by measuring overlay marks with traditional metrology is difficult because of the difference of shape and position between cell pattern and overlay marks. Cell to overlay mark miss-match will occur when there is lens aberration or mask registration error. Therefore, the best way to obtain accurate overlay data without error is to measure the real cell itself. The overlay of the cell array using DPT process can be measured by analyzing the relative position of the 2nd exposed pattern to the 1st exposed pattern. But it is not easy to clearly distinguish a 1st layer and 2nd layer in a patterned cell array image using CD SEM. The Design Based Metrology (DBM)-system can help identify which cell pattern is a 1st or 2nd layer, so overlay error between the 1st and 2nd layers at DPT process can be checked clearly. Another noticeable problem in advanced processing is wiggling. The wiggling of a pattern become severe by the etch process and must be controlled to meet electrical characteristics of what the semiconductor device requires. The 1st stage of wiggling control is to understand the level of wiggling which is crucial to device performance. The DBM-system also can be used for quantification of wiggling by determining specially designed parameters. In this paper we introduce overlay verification and wiggling quantification through new methodology for advanced memory devices.

  18. Computer vision and soft computing for automatic skull-face overlay in craniofacial superimposition.

    Science.gov (United States)

    Campomanes-Álvarez, B Rosario; Ibáñez, O; Navarro, F; Alemán, I; Botella, M; Damas, S; Cordón, O

    2014-12-01

    Craniofacial superimposition can provide evidence to support that some human skeletal remains belong or not to a missing person. It involves the process of overlaying a skull with a number of ante mortem images of an individual and the analysis of their morphological correspondence. Within the craniofacial superimposition process, the skull-face overlay stage just focuses on achieving the best possible overlay of the skull and a single ante mortem image of the suspect. Although craniofacial superimposition has been in use for over a century, skull-face overlay is still applied by means of a trial-and-error approach without an automatic method. Practitioners finish the process once they consider that a good enough overlay has been attained. Hence, skull-face overlay is a very challenging, subjective, error prone, and time consuming part of the whole process. Though the numerical assessment of the method quality has not been achieved yet, computer vision and soft computing arise as powerful tools to automate it, dramatically reducing the time taken by the expert and obtaining an unbiased overlay result. In this manuscript, we justify and analyze the use of these techniques to properly model the skull-face overlay problem. We also present the automatic technical procedure we have developed using these computational methods and show the four overlays obtained in two craniofacial superimposition cases. This automatic procedure can be thus considered as a tool to aid forensic anthropologists to develop the skull-face overlay, automating and avoiding subjectivity of the most tedious task within craniofacial superimposition. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  19. OMI/Aura Level 1B UV Global Geolocated Earthshine Radiances 1-orbit L2 Swath 13x24 km V003 (OML1BRUG) at GES DISC

    Data.gov (United States)

    National Aeronautics and Space Administration — The Aura Ozone Monitoring Instrument (OMI) Level-1B (L1B) Geo-located Earth View UV Radiance, Global-Mode (OML1BRUG) Version-3 product is now available to public...

  20. The concept of 'overlay' in relation to the Open Archives Initiative Protocol for Metadata Harvesting (OAI-PMH)

    OpenAIRE

    Enger, Magnus

    2005-01-01

    The evolution of scholarly documentation is discussed in light of the theory of the "ecology of documentation". The OAI-PMH is presented, and a survey of features found in existing service providers/overlays is presented. A prototype overlay incorporating features of wikis and "tagging" is presented along with some thoughts on how overlays may evolve and differentiate in the future.

  1. Focused-ion-beam overlay-patterning of three-dimensional diamond structures for advanced single-photon properties

    Science.gov (United States)

    Jiang, Qianqing; Liu, Dongqi; Liu, Gangqin; Chang, Yanchun; Li, Wuxia; Pan, Xinyu; Gu, Changzhi

    2014-07-01

    Sources of single photons are of fundamental importance in many applications as to provide quantum states for quantum communication and quantum information processing. Color centers in diamond are prominent candidates to generate and manipulate quantum states of light, even at room temperature. However, the efficiency of photon collection of the color centers in bulk diamond is greatly reduced by refraction at the diamond/air interface. To address this issue, diamond structuring has been investigated by various methods. Among them, focused-ion-beam (FIB) direct patterning has been recognized as the most favorable technique. But it has been noted that diamond tends to present significant challenges in FIB milling, e.g., the susceptibility of forming charging related artifacts and topographical features. In this work, periodically-positioned-rings and overlay patterning with stagger-superimposed-rings were proposed to alleviate some problems encountered in FIB milling of diamond, for improved surface morphology and shape control. Cross-scale network and uniform nanostructure arrays have been achieved in single crystalline diamond substrates. High quality diamond solid immersion lens and nanopillars were sculptured with a nitrogen-vacancy center buried at the desired position. Compared with the film counterpart, an enhancement of about ten folds in single photon collection efficiency was achieved with greatly improved signal to noise ratio. All these results indicate that FIB milling through over-lay patterning could be an effective approach to fabricate diamond structures, potentially for quantum information studies.

  2. Service delivery aspects in a reconfigurable photonic access network

    NARCIS (Netherlands)

    Roy, R.; Manhoudt, Gert; van Etten, Wim

    2008-01-01

    We discuss service delivery aspects in a reconfigurable photonic access network. The network is viewed as a stack of logical PONs in which a DWDM overlay is used over TDM PONs operating in their native format. The use of optical routers in the network allows for a dynamic change in the network

  3. The performances of different overlay mark types at 65nm node on 300-mm wafers

    Science.gov (United States)

    Tseng, H. T.; Lin, Ling-Chieh; Huang, I. H.; Lin, Benjamin S.; Huang, Chin-Chou K.; Huang, Chien-Jen

    2005-05-01

    The integrated circuit (IC) manufacturing factories have measured overlay with conventional "box-in-box" (BiB) or "frame-in-frame" (FiF) structures for many years. Since UMC played as a roll of world class IC foundry service provider, tighter and tighter alignment accuracy specs need to be achieved from generation to generation to meet any kind of customers' requirement, especially according to International Technology Roadmap for Semiconductors (ITRS) 2003 METROLOGY section1. The process noises resulting from dishing, overlay mark damaging by chemical mechanism polishing (CMP), and the variation of film thickness during deposition are factors which can be very problematic in mark alignment. For example, the conventional "box-in-box" overlay marks could be damaged easily by CMP, because the less local pattern density and wide feature width of the box induce either dishing or asymmetric damages for the measurement targets, which will make the overlay measurement varied and difficult. After Advanced Imaging Metrology (AIM) overlay targets was introduced by KLA-Tencor, studies in the past shown AIM was more robust in overlay metrology than conventional FiF or BiB targets. In this study, the applications of AIM overlay marks under different process conditions will be discussed and compared with the conventional overlay targets. To evaluate the overlay mark performance against process variation on 65nm technology node in 300-mm wafer, three critical layers were chosen in this study. These three layers were Poly, Contact, and Cu-Metal. The overlay targets used for performance comparison were BiB and Non-Segmented AIM (NS AIM) marks. We compared the overlay mark performance on two main areas. The first one was total measurement uncertainty (TMU)3 related items that include Tool Induced Shift (TIS) variability, precision, and matching. The other area is the target robustness against process variations. Based on the present study AIM mark demonstrated an equal or better

  4. Overlay performance assessment of MAPPER's FLX-1200 (Conference Presentation)

    Science.gov (United States)

    Lattard, Ludovic; Servin, Isabelle; Pradelles, Jonathan; Blancquaert, Yoann; Rademaker, Guido; Pain, Laurent; de Boer, Guido; Brandt, Pieter; Dansberg, Michel; Jager, Remco J. A.; Peijster, Jerry J. M.; Slot, Erwin; Steenbrink, Stijn W. H. K.; Vergeer, Niels; Wieland, Marco

    2017-04-01

    Mapper Lithography has introduced its first product, the FLX-1200, which is installed at CEA-Leti in Grenoble (France). This is a mask less lithography system, based on massively parallel electron-beam writing with high-speed optical data transport for switching the electron beams. This FLX platform is initially targeted for 1 wph performance for 28 nm technology nodes, but can also be used for less demanding imaging. The electron source currently integrated is capable of scaling to 10 wph at the same resolution performance, which will be implemented by gradually upgrading the illumination optics. The system has an optical alignment system enabling mix-and-match with optical 193 nm immersion systems using standard NVSM marks. The tool at CEA-Leti is in-line with a Sokudo Duo clean track. Mapper Lithography and CEA-Leti are working in collaboration to develop turnkey solution for specific applications. At previous conferences we have presented imaging results including 28nm node resolution, cross wafer CDu of 2.5nm 3 and a throughput of half a wafer per hour, overhead times included. At this conference we will present results regarding the overlay performance of the FLX-1200. In figure 2 an initial result towards measuring the overlay performance of the FLX-1200 is shown. We have exposed a wafer twice without unloading the wafer in between exposures. In the first exposure half of a dense dot array is exposed. In the second exposure the remainder of the dense dot array is exposed. After development the wafer has been inspected using a CD-SEM at 480 locations distributed over an area of 100mm x 100mm. For each SEM image the shift of the pattern written in the first exposure relative to the pattern written in the second exposure is measured. Cross wafer this shift is 7 nm u+3s in X and 5 nm u+3s in Y. The next step is to evaluate the impact of unloading and loading of the wafer in between exposures. At the conference the latest results will be presented.

  5. Structured P2P Overlay of Mobile Brokers for Realizing Publish/Subscribe Communication in VANET

    Directory of Open Access Journals (Sweden)

    Tulika Pandey

    2014-01-01

    Full Text Available Publish/subscribe communication paradigm provides asynchrony and decoupling, making it an elegant alternative for designing applications in distributed and dynamic environment such as vehicular ad hoc networks (VANETs. In this paradigm, the broker is the most important component that decouples other two components, namely, publisher and subscriber. Previous research efforts have either utilized the deployment of distributed brokers on stationary road side info-stations or have assigned the role of broker to any moving vehicle on ad hoc basis. In one approach, lots of preinstalled infrastructures are needed whereas, in another, the quality of service is not guaranteed due to unpredictable moving and stopping patterns of vehicles. In this paper, we present the architecture of distributed mobile brokers which are dynamically reconfigurable in the form of structured P2P overlay and act as rendezvous points for matching publications and subscriptions. We have taken city buses in urban settings to act as mobile brokers whereas other vehicles are considered to be in role of publishers and subscribers. These mobile brokers also assist in locating a vehicle for successful and timely transfer of notifications. We have performed an extensive simulation study to compare our approach with previously proposed approaches. Simulation results establish the applicability of our approach.

  6. Structured P2P Overlay of Mobile Brokers for Realizing Publish/Subscribe Communication in VANET

    Science.gov (United States)

    Pandey, Tulika; Garg, Deepak; Gore, Manoj Madhava

    2014-01-01

    Publish/subscribe communication paradigm provides asynchrony and decoupling, making it an elegant alternative for designing applications in distributed and dynamic environment such as vehicular ad hoc networks (VANETs). In this paradigm, the broker is the most important component that decouples other two components, namely, publisher and subscriber. Previous research efforts have either utilized the deployment of distributed brokers on stationary road side info-stations or have assigned the role of broker to any moving vehicle on ad hoc basis. In one approach, lots of preinstalled infrastructures are needed whereas, in another, the quality of service is not guaranteed due to unpredictable moving and stopping patterns of vehicles. In this paper, we present the architecture of distributed mobile brokers which are dynamically reconfigurable in the form of structured P2P overlay and act as rendezvous points for matching publications and subscriptions. We have taken city buses in urban settings to act as mobile brokers whereas other vehicles are considered to be in role of publishers and subscribers. These mobile brokers also assist in locating a vehicle for successful and timely transfer of notifications. We have performed an extensive simulation study to compare our approach with previously proposed approaches. Simulation results establish the applicability of our approach. PMID:24523629

  7. Spatial Point Data Analysis of Geolocated Tweets in the First Day of Eid Al-Fitr 2017 in Java Island

    Science.gov (United States)

    Wibowo, T. W.

    2017-12-01

    Eid Al-Fitr is a worldwide Muslim feast day, which in Indonesia generally accompanied by tradition of going home (mudik). The demographic patterns at the time of the holiday are generally shifted, in which some urban residents will travel to their hometowns. The impact of this shifting is that there is a quite massive mobility of the population, which is generally accompanied by traffic congestion. The presence of location sensors on smartphone devices, open the opportunity to map the movement of the population in realtime or near-realtime. Especially now that social media applications have been integrated with the capability to include location information. One of the popular social media applications in Indonesia is Twitter, which provides microblogging facilities to its users. This study aims to analyze the pattern of Geolocated Tweets data uploaded by Twitter users on the first day of Eid Al-Fitr (1 Syawal 1438H). Geolocated Tweets data mining is done by using Streaming API (Application Programming Interface) and Python programming language. There are 13,224 Geolocated Tweets points obtained at the location of the study. Various point data analysis techniques applied to the data have been collected, such as density analysis, pattern analysis, and proximity analysis. In general, active Twitter users are dominated by residents in major cities, such as Jakarta, Bandung, Surabaya, Yogyakarta, Surakarta and Semarang. The results of the analysis can be used to determine whether the Geolocated Tweets data mined by the Streaming API method can be used to represent the movement of the population when mudik.

  8. A hidden Markov model for reconstructing animal paths from solar geolocation loggers using templates for light intensity.

    Science.gov (United States)

    Rakhimberdiev, Eldar; Winkler, David W; Bridge, Eli; Seavy, Nathaniel E; Sheldon, Daniel; Piersma, Theunis; Saveliev, Anatoly

    2015-01-01

    Solar archival tags (henceforth called geolocators) are tracking devices deployed on animals to reconstruct their long-distance movements on the basis of locations inferred post hoc with reference to the geographical and seasonal variations in the timing and speeds of sunrise and sunset. The increased use of geolocators has created a need for analytical tools to produce accurate and objective estimates of migration routes that are explicit in their uncertainty about the position estimates. We developed a hidden Markov chain model for the analysis of geolocator data. This model estimates tracks for animals with complex migratory behaviour by combining: (1) a shading-insensitive, template-fit physical model, (2) an uncorrelated random walk movement model that includes migratory and sedentary behavioural states, and (3) spatially explicit behavioural masks. The model is implemented in a specially developed open source R package FLightR. We used the particle filter (PF) algorithm to provide relatively fast model posterior computation. We illustrate our modelling approach with analysis of simulated data for stationary tags and of real tracks of both a tree swallow Tachycineta bicolor migrating along the east and a golden-crowned sparrow Zonotrichia atricapilla migrating along the west coast of North America. We provide a model that increases accuracy in analyses of noisy data and movements of animals with complicated migration behaviour. It provides posterior distributions for the positions of animals, their behavioural states (e.g., migrating or sedentary), and distance and direction of movement. Our approach allows biologists to estimate locations of animals with complex migratory behaviour based on raw light data. This model advances the current methods for estimating migration tracks from solar geolocation, and will benefit a fast-growing number of tracking studies with this technology.

  9. wayGoo: a platform for geolocating and managing indoor and outdoor spaces

    Science.gov (United States)

    Thomopoulos, Stelios C. A.; Karafylli, Christina; Karafylli, Maria; Motos, Dionysis; Lampropoulos, Vassilis; Dimitros, Kostantinos; Margonis, Christos

    2016-05-01

    wayGoo2 is a platform for Geolocating and Managing indoor and outdoor spaces and content with multidimensional indoor and outdoor Navigation and Guidance. Its main components are a Geographic Information System, a back-end server, front-end applications and a web-based Content Management System (CMS). It constitutes a fully integrated 2D/3D space and content management system that creates a repository that consists of a database, content components and administrative data. wayGoo can connect to any third party database and event management data-source. The platform is secure as the data is only available through a Restful web service using https security protocol in conjunction with an API key used for authentication. To enhance users experience, wayGoo makes the content available by extracting components out of the repository and constructing targeted applications. The wayGoo platform supports geo-referencing of indoor and outdoor information and use of metadata. It also allows the use of existing information such as maps and databases. The platform enables planning through integration of content that is connected either spatially, temporally or contextually, and provides immediate access to all spatial data through interfaces and interactive 2D and 3D representations. wayGoo constitutes a mean to document and preserve assets through computerized techniques and provides a system that enhances the protection of your space, people and guests when combined with wayGoo notification and alert system. It constitutes a strong marketing tool providing staff and visitors with an immersive tool for navigation in indoor spaces and allowing users to organize their agenda and to discover events through wayGoo event scheduler and recommendation system. Furthermore, the wayGoo platform can be used in Security applications and event management, e.g. CBRNE incidents, man-made and natural disasters, etc., to document and geolocate information and sensor data (off line and real time

  10. Asphalt Concrete Overlay Optimization Based on Pavement Performance Models

    Directory of Open Access Journals (Sweden)

    Jan Mikolaj

    2017-01-01

    Full Text Available The life cycle length of pavement with asphalt concrete material (ACM surfacing is significantly influenced, in addition to transport loading and climatic conditions, by design method and rehabilitation timing. Appropriate overlay thickness calculation and estimation of optimal rehabilitation time are crucial to maximizing life cycle length and, concurrently, reducing road administration costs and road user costs. This article describes a comprehensive method of ACM rehabilitation design. For optimization of life cycle cost analysis (LCCA based design, mathematical analytical solution in combination with experimental verification of physical, mechanical, and fatigue characteristics is utilized. Pavement performance, that is, functions mathematically describing pavement’s degradation characteristics of operational capability, is represented by longitudinal and transverse unevenness; these are used to describe relations between traffic loading and pavement’s bearing capacity on 1 : 1 scale. Optimizing of rehabilitation plan is carried out by making a cost benefit analysis (CBA for several rehabilitation scenarios in which different rehabilitation timing produces different capital cost requirements and social benefits. Rehabilitation scenarios differ in technology, the design of which needs to be mathematically optimized, and timing of rehabilitation execution. This article includes a case study for the sake of illustration of practical results and verification of applicability of used methodology.

  11. Augmented Endoscopic Images Overlaying Shape Changes in Bone Cutting Procedures.

    Science.gov (United States)

    Nakao, Megumi; Endo, Shota; Nakao, Shinichi; Yoshida, Munehito; Matsuda, Tetsuya

    2016-01-01

    In microendoscopic discectomy for spinal disorders, bone cutting procedures are performed in tight spaces while observing a small portion of the target structures. Although optical tracking systems are able to measure the tip of the surgical tool during surgery, the poor shape information available during surgery makes accurate cutting difficult, even if preoperative computed tomography and magnetic resonance images are used for reference. Shape estimation and visualization of the target structures are essential for accurate cutting. However, time-varying shape changes during cutting procedures are still challenging issues for intraoperative navigation. This paper introduces a concept of endoscopic image augmentation that overlays shape changes to support bone cutting procedures. This framework handles the history of the location of the measured drill tip as a volume label and visualizes the remains to be cut overlaid on the endoscopic image in real time. A cutting experiment was performed with volunteers, and the feasibility of this concept was examined using a clinical navigation system. The efficacy of the cutting aid was evaluated with respect to the shape similarity, total moved distance of a cutting tool, and required cutting time. The results of the experiments showed that cutting performance was significantly improved by the proposed framework.

  12. Design of ultra high performance concrete as an overlay in pavements and bridge decks.

    Science.gov (United States)

    2014-08-01

    The main objective of this research was to develop ultra-high performance concrete (UHPC) as a reliable, economic, low carbon foot : print and durable concrete overlay material that can offer shorter traffic closures due to faster construction. The U...

  13. The Effect of Colored Overlays on Reading Fluency in Individuals with Dyslexia.

    Science.gov (United States)

    Denton, Tiffany Freeze; Meindl, James N

    2016-09-01

    Colored overlays, one type of tinted filter, are plastic reading sheets tinted with color and placed over text to eliminate or alleviate a wide range of reading difficulties such as low reading rate, accuracy, and comprehension. The effects of colored overlays on reading problems associated with dyslexia were investigated in this study via a multielement design. Reading fluency was assessed when participants read with and without colored overlays. Undifferentiated responding, or decreased accuracy, resulted across three participants, suggesting that colored overlays were ineffective and potentially detrimental to participants' reading abilities. As a result, empirically validated reading techniques were implemented across individuals. These findings are discussed and recommendations are made in regards to the use of research-based reading interventions.

  14. Texas flexible pavements and overlays : calibration plans for M-E models and related software.

    Science.gov (United States)

    2013-06-01

    This five-year project was initiated to collect materials and pavement performance data on a minimum of 100 highway test sections around the State of Texas, incorporating flexible pavements and overlays. Besides being used to calibrate and validate m...

  15. Cracking and debonding of a thin fiber reinforced concrete overlay : research brief.

    Science.gov (United States)

    2017-03-01

    Experimental tests found that the tensile interfacial energy : increased with fiber-reinforcement. Also bond tests indicated : that interfacial fracture occurred through the overlay mixture and : was proportional to the number of fibers which interse...

  16. Evaluation of a thin-bonded Portland cement concrete pavement overlay.

    Science.gov (United States)

    1996-01-01

    This report discusses the performance of the Virginia Department of Transportation's first modern rehabilitation project involving a thin-bonded portland cement concrete overlay of an existing jointed concrete pavement. The performance of the rigid o...

  17. Use of infrared thermography to detect thermal segregation in asphalt overlay and reflective cracking potential.

    Science.gov (United States)

    2015-03-01

    The objectives of this study were to assess whether temperature differentials measured using Infrared : Thermography (IRT) occur in an overlay built on top of discontinuities such as joints and cracks and to : study the horizontal and vertical therma...

  18. ViTexOCR; a script to extract text overlays from digital video

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The ViTexOCR script presents a new method for extracting navigation data from videos with text overlays using optical character recognition (OCR) software. Over the...

  19. Effect of SiO2 Overlayer on WO3 Sensitivity to Ammonia

    Directory of Open Access Journals (Sweden)

    Vibha Srivastava

    2010-06-01

    Full Text Available Ammonia gas sensing properties of tungsten trioxide thick film sensor was investigated. The doping of noble catalysts such as Pt, Pd, Au enhanced the gas sensitivity. Platinum doping was found to result in highest sensitivity. Remarkable sensitivity enhancement was realized by coating WO3 thick film sensors with SiO2 overlayer. Sol gel process derived silica overlayer increased ammonia gas sensitivity for doped as well as undoped sensor.

  20. Reducing the overlay metrology sensitivity to perturbations of the measurement stack

    Science.gov (United States)

    Zhou, Yue; Park, DeNeil; Gutjahr, Karsten; Gottipati, Abhishek; Vuong, Tam; Bae, Sung Yong; Stokes, Nicholas; Jiang, Aiqin; Hsu, Po Ya; O'Mahony, Mark; Donini, Andrea; Visser, Bart; de Ruiter, Chris; Grzela, Grzegorz; van der Laan, Hans; Jak, Martin; Izikson, Pavel; Morgan, Stephen

    2017-03-01

    Overlay metrology setup today faces a continuously changing landscape of process steps. During Diffraction Based Overlay (DBO) metrology setup, many different metrology target designs are evaluated in order to cover the full process window. The standard method for overlay metrology setup consists of single-wafer optimization in which the performance of all available metrology targets is evaluated. Without the availability of external reference data or multiwafer measurements it is hard to predict the metrology accuracy and robustness against process variations which naturally occur from wafer-to-wafer and lot-to-lot. In this paper, the capabilities of the Holistic Metrology Qualification (HMQ) setup flow are outlined, in particular with respect to overlay metrology accuracy and process robustness. The significance of robustness and its impact on overlay measurements is discussed using multiple examples. Measurement differences caused by slight stack variations across the target area, called grating imbalance, are shown to cause significant errors in the overlay calculation in case the recipe and target have not been selected properly. To this point, an overlay sensitivity check on perturbations of the measurement stack is presented for improvement of the overlay metrology setup flow. An extensive analysis on Key Performance Indicators (KPIs) from HMQ recipe optimization is performed on µDBO measurements of product wafers. The key parameters describing the sensitivity to perturbations of the measurement stack are based on an intra-target analysis. Using advanced image analysis, which is only possible for image plane detection of μDBO instead of pupil plane detection of DBO, the process robustness performance of a recipe can be determined. Intra-target analysis can be applied for a wide range of applications, independent of layers and devices.

  1. Turisbook: Social Network of Tourism with Geographical Information

    Science.gov (United States)

    García, Eva; García, Antonio; de-Marcos, Luis; Hilera, José-Ramón

    This article presents the social network of tourism Turisbook. This social network allows sharing information and opinions about worldwide travel destinations. It incorporates a geo-location system of points on a map, so that user can search quickly and easily tourist points in a given area. The system allows users to upload their own tourist points with associated information and photos. In this manner, the system feeds with user contributions, allowing discovering places that usually do not appear in traditional guidebooks.

  2. VMCast: A VM-Assisted Stability Enhancing Solution for Tree-Based Overlay Multicast.

    Directory of Open Access Journals (Sweden)

    Weidong Gu

    Full Text Available Tree-based overlay multicast is an effective group communication method for media streaming applications. However, a group member's departure causes all of its descendants to be disconnected from the multicast tree for some time, which results in poor performance. The above problem is difficult to be addressed because overlay multicast tree is intrinsically instable. In this paper, we proposed a novel stability enhancing solution, VMCast, for tree-based overlay multicast. This solution uses two types of on-demand cloud virtual machines (VMs, i.e., multicast VMs (MVMs and compensation VMs (CVMs. MVMs are used to disseminate the multicast data, whereas CVMs are used to offer streaming compensation. The used VMs in the same cloud datacenter constitute a VM cluster. Each VM cluster is responsible for a service domain (VMSD, and each group member belongs to a specific VMSD. The data source delivers the multicast data to MVMs through a reliable path, and MVMs further disseminate the data to group members along domain overlay multicast trees. The above approach structurally improves the stability of the overlay multicast tree. We further utilized CVM-based streaming compensation to enhance the stability of the data distribution in the VMSDs. VMCast can be used as an extension to existing tree-based overlay multicast solutions, to provide better services for media streaming applications. We applied VMCast to two application instances (i.e., HMTP and HCcast. The results show that it can obviously enhance the stability of the data distribution.

  3. Hybrid Terrestrial-Satellite DVB/IP Infrastructure in Overlay Constellations for Triple-Play Services Access in Rural Areas

    Directory of Open Access Journals (Sweden)

    E. Pallis

    2010-01-01

    Full Text Available This paper discusses the convergence of digital broadcasting and Internet technologies, by elaborating on the design, implementation, and performance evaluation of a hybrid terrestrial/satellite networking infrastructure, enabling triple-play services access in rural areas. At local/district level, the paper proposes the exploitation of DVB-T platforms in regenerative configurations for creating terrestrial DVB/IP backhaul between the core backbone (in urban areas and a number of intermediate communication nodes distributed within the DVB-T broadcasting footprint (in rural areas. In this way, triple play services that are available at the core backbone, are transferred via the regenerative DVB-T/IP backhaul to the entire district and can be accessed by rural users via the corresponding intermediate node. On the other hand, at regional/national level, the paper proposes the exploitation of a satellite interactive digital video broadcasting platform (DVB S2/RCS as an overlay network that interconnects the regenerative DVB-T/IP platforms, as well as individual users, and services providers, to each other. Performance of the proposed hybrid terrestrial/satellite networking environment is validated through experimental tests that were conducted under real transmission/reception conditions (for the terrestrial segment and via simulation experiments (for the satellite segment at a prototype network infrastructure.

  4. implementation of internet protocol network architecture

    African Journals Online (AJOL)

    User

    ABSTRACT. Advances in multimedia technologies and development of overlay networks foster the opportu- nity for creating new value-added services over the current Internet. In this paper, a new service network architecture that supports multiparty multimedia conferencing applications, character- istics of which include ...

  5. Using the overlay assay to qualitatively measure bacterial production of and sensitivity to pneumococcal bacteriocins.

    Science.gov (United States)

    Maricic, Natalie; Dawid, Suzanne

    2014-09-30

    Streptococcus pneumoniae colonizes the highly diverse polymicrobial community of the nasopharynx where it must compete with resident organisms. We have shown that bacterially produced antimicrobial peptides (bacteriocins) dictate the outcome of these competitive interactions. All fully-sequenced pneumococcal strains harbor a bacteriocin-like peptide (blp) locus. The blp locus encodes for a range of diverse bacteriocins and all of the highly conserved components needed for their regulation, processing, and secretion. The diversity of the bacteriocins found in the bacteriocin immunity region (BIR) of the locus is a major contributor of pneumococcal competition. Along with the bacteriocins, immunity genes are found in the BIR and are needed to protect the producer cell from the effects of its own bacteriocin. The overlay assay is a quick method for examining a large number of strains for competitive interactions mediated by bacteriocins. The overlay assay also allows for the characterization of bacteriocin-specific immunity, and detection of secreted quorum sensing peptides. The assay is performed by pre-inoculating an agar plate with a strain to be tested for bacteriocin production followed by application of a soft agar overlay containing a strain to be tested for bacteriocin sensitivity. A zone of clearance surrounding the stab indicates that the overlay strain is sensitive to the bacteriocins produced by the pre-inoculated strain. If no zone of clearance is observed, either the overlay strain is immune to the bacteriocins being produced or the pre-inoculated strain does not produce bacteriocins. To determine if the blp locus is functional in a given strain, the overlay assay can be adapted to evaluate for peptide pheromone secretion by the pre-inoculated strain. In this case, a series of four lacZ-reporter strains with different pheromone specificity are used in the overlay.

  6. Evaluation of Tizian overlays by means of a swept source optical coherence tomography system

    Science.gov (United States)

    Marcauteanu, Corina; Sinescu, Cosmin; Negrutiu, Meda Lavinia; Stoica, Eniko Tunde; Topala, Florin; Duma, Virgil Florin; Bradu, Adrian; Podoleanu, Adrian Gh.

    2016-03-01

    The teeth affected by pathologic attrition can be restored by a minimally invasive approach, using Tizian overlays. In this study we prove the advantages of a fast swept source (SS) OCT system in the evaluation of Tizian overlays placed in an environment characterized by high occlusal forces. 12 maxillary first premolars were extracted and prepared for overlays. The Tizian overlays were subjected to 3000 alternating cycles of thermo-cycling (from -10°C to +50°C) and to mechanical occlusal overloads (at 800 N). A fast SS OCT system was used to evaluate the Tizian overlays before and after the mechanical and thermal straining. The SS (Axsun Technologies, Billerica, MA) has a central wavelength of 1060 nm, sweeping range of 106 nm (quoted at 10 dB) and a 100 kHz line rate. The depth resolution of the system, measured experimentally in air was 10 μm. The imaging system used for this study offers high spatial resolutions in both directions, transversal and longitudinal of around 10 μm, a high sensitivity, and it is also able to acquire entire tridimensional (3D)/volume reconstructions as fast as 2.5 s. Once the full dataset was acquired, rendered high resolutions en-face projections could be produced. Using them, the overlay (i.e., cement) abutment tooth interfaces were remarked both on B-scans/two-dimensional (2D) sections and in the 3D reconstructions. Using the system several open interfaces were possible to detect. The fast SS OCT system thus proves useful in the evaluation of zirconia reinforced composite overlays, placed in an environment characterized by high occlusal forces.

  7. The power of vertical geolocation of atmospheric profiles from GNSS radio occultation.

    Science.gov (United States)

    Scherllin-Pirscher, Barbara; Steiner, Andrea K; Kirchengast, Gottfried; Schwärz, Marc; Leroy, Stephen S

    2017-02-16

    High-resolution measurements from Global Navigation Satellite System (GNSS) radio occultation (RO) provide atmospheric profiles with independent information on altitude and pressure. This unique property is of crucial advantage when analyzing atmospheric characteristics that require joint knowledge of altitude and pressure or other thermodynamic atmospheric variables. Here we introduce and demonstrate the utility of this independent information from RO and discuss the computation, uncertainty, and use of RO atmospheric profiles on isohypsic coordinates-mean sea level altitude and geopotential height-as well as on thermodynamic coordinates (pressure and potential temperature). Using geopotential height as vertical grid, we give information on errors of RO-derived temperature, pressure, and potential temperature profiles and provide an empirical error model which accounts for seasonal and latitudinal variations. The observational uncertainty of individual temperature/pressure/potential temperature profiles is about 0.7 K/0.15%/1.4 K in the tropopause region. It gradually increases into the stratosphere and decreases toward the lower troposphere. This decrease is due to the increasing influence of background information. The total climatological error of mean atmospheric fields is, in general, dominated by the systematic error component. We use sampling error-corrected climatological fields to demonstrate the power of having different and accurate vertical coordinates available. As examples we analyze characteristics of the location of the tropopause for geopotential height, pressure, and potential temperature coordinates as well as seasonal variations of the midlatitude jet stream core. This highlights the broad applicability of RO and the utility of its versatile vertical geolocation for investigating the vertical structure of the troposphere and stratosphere.

  8. Geolocators reveal migration and pre-breeding behaviour of the critically endangered Balearic Shearwater Puffinus mauretanicus.

    Science.gov (United States)

    Guilford, Tim; Wynn, Russell; McMinn, Miguel; Rodríguez, Ana; Fayet, Annette; Maurice, Lou; Jones, Alice; Meier, Rhiannon

    2012-01-01

    Using combined miniature archival light and salt-water immersion loggers, we characterise the year-round individual at-sea movements of Europe's only critically endangered seabird, the Balearic shearwater Puffinus mauretanicus, for the first time. Focusing on the non-breeding period, we show that all of the 26 breeding birds tracked from their breeding site on Mallorca in the Mediterranean Sea successfully made a 2-4 month migration into the Atlantic Ocean, where they utilised well-defined core areas off Portuguese and French coasts. As well as identifying high-risk areas in the Atlantic, our results confirm that breeding birds spend most of the year concentrated around productive waters of the Iberian shelf in the western Mediterranean. Migration phenology appeared largely unrelated to the subsequent (distinctly synchronous) breeding attempt, suggesting that any carry-over effects were compensated for during a long pre-laying period spent over winter in the Mediterranean. Using the light and salt-water immersion data alone we were also able to characterise the pattern of pre-laying visits to the colony in considerable detail, demonstrating that breeding pairs appear to coordinate their over-day visits using a high frequency of night-time visits throughout the winter. Our study shows that geolocation technology is a valuable tool for assessing the spatial distribution of risks to this critically endangered species, and also provides a low-impact method for remotely observing the detailed behaviour of seabird species that may be sensitive to disturbance from traditional study methods.

  9. Geolocation of man-made reservoirs across terrains of varying complexity using GIS

    Science.gov (United States)

    Mixon, D.M.; Kinner, D.A.; Stallard, R.F.; Syvitski, J.P.M.

    2008-01-01

    The Reservoir Sedimentation Survey Information System (RESIS) is one of the world's most comprehensive databases of reservoir sedimentation rates, comprising nearly 6000 surveys for 1819 reservoirs across the continental United States. Sediment surveys in the database date from 1904 to 1999, though more than 95% of surveys were entered prior to 1980, making RESIS largely a historical database. The use of this database for large-scale studies has been limited by the lack of precise coordinates for the reservoirs. Many of the reservoirs are relatively small structures and do not appear on current USGS topographic maps. Others have been renamed or have only approximate (i.e. township and range) coordinates. This paper presents a method scripted in ESRI's ARC Macro Language (AML) to locate the reservoirs on digital elevation models using information available in RESIS. The script also delineates the contributing watersheds and compiles several hydrologically important parameters for each reservoir. Evaluation of the method indicates that, for watersheds larger than 5 km2, the correct outlet is identified over 80% of the time. The importance of identifying the watershed outlet correctly depends on the application. Our intent is to collect spatial data for watersheds across the continental United States and describe the land use, soils, and topography for each reservoir's watershed. Because of local landscape similarity in these properties, we show that choosing the incorrect watershed does not necessarily mean that the watershed characteristics will be misrepresented. We present a measure termed terrain complexity and examine its relationship to geolocation success rate and its influence on the similarity of nearby watersheds. ?? 2008 Elsevier Ltd. All rights reserved.

  10. Survivable resource orchestration for optically interconnected data center networks.

    Science.gov (United States)

    Zhang, Qiong; She, Qingya; Zhu, Yi; Wang, Xi; Palacharla, Paparao; Sekiya, Motoyoshi

    2014-01-13

    We propose resource orchestration schemes in overlay networks enabled by optical network virtualization. Based on the information from underlying optical networks, our proposed schemes provision the fewest data centers to guarantee K-connect survivability, thus maintaining resource availability for cloud applications under any failure.

  11. An approach to a transparent self-healing meshed network

    DEFF Research Database (Denmark)

    Larsen, Claus Popp; Limal, Emmanuel

    1997-01-01

    A method of implementing a transparent self-healing meshed network is described here. In case of a cable break or signal detoriation, this network will perform protection switching without needing direct correspondance with the overlaying management system. This causes simpler network management ...

  12. Isotopes and trace elements as geo-location markers for biosecurity: determining the origin of exotic pests.

    Science.gov (United States)

    Holder, Peter W.; Armstrong, Karen; Clough, Tim; Frew, Russell; van Hale, Robert; Baker, Joel A.; Millet, Marc-Alban

    2010-05-01

    Background. The benefits of accurate point of origin discrimination in biosecurity include achieving appropriate operational responses in exotic pest eradication and post-border incursion campaigns, and identifying risk pathways. Reading natural abundance biogeochemical markers via mass spectrometry methods is a powerful tool for tracing ecological pathways and provenance determination of agricultural products and items of forensic interest. However, the application of these methods to trace insects - man's most damaging competitors - has been underutilised to date and our understanding in this field is still in a phase of basic development. Stable isotope ratio analyses using δ2H, δ13C have given spatial resolution in the monarch butterfly, single host system in eastern North America. Subsequently, the same method was employed in an attempt to determine the origin of important biosecurity pests in New Zealand. However, the results were contentious as the accuracy and limitations of the method in a biosecurity application were unknown. Further investigation has shown the value of existing invertebrate stable isotope geo-location methodology (i.e., using only two light elements) is tenuous in the biosecurity context, where the sample sizes are usually only one or two insects, and the specimens are generally polyphagous and accidentally introduced, and so from an unknown and unpredictable place, point in time and host: The spatial distribution of 2H in New Zealand may not be reliable over insect life-span time-scales; and fractional variables are un-quantified and potentially overwhelm any New Zealand signal. Further, the geo-location value of 13C is uncertain, especially for polyphagous insects. Research aims. The internationally distributed Helicoverpa armigera [Noctuidae] is being used to examine the processes fundamental to the location-to-plant-to-insect biogeochemical profile imprinting in phytophagous insects, including the turn over of elements in adult

  13. A comparative study of three commonly used two-dimensional overlay generation methods in bite mark analysis

    OpenAIRE

    Pajnigara, Nilufer Gev; Balpande, Apeksha S; Motwani, Mukta B; Choudhary, Anuraag; Thakur, Samantha; Pajnigara, Natasha G

    2017-01-01

    Aim: The present study attempts to compare the bite mark overlays generated by three different methods. The objectives of the study were to compare the three commonly used techniques for overlay generation and to evaluate the interobserver reliability in assessing bite marks by these methods. Materials and Methods: Overlays were produced from the biting surfaces of six upper and six lower anterior teeth of 30 dental study models using the following three methods: (a) Hand tracing from wax imp...

  14. Infrared differential interference contrast microscopy for overlay metrology on 3D-interconnect bonded wafers

    Science.gov (United States)

    Ku, Yi-sha; Shyu, Deh-Ming; Lin, Yeou-Sung; Cho, Chia-Hung

    2013-04-01

    Overlay metrology for stacked layers will be playing a key role in bringing 3D IC devices into manufacturing. However, such bonded wafer pairs present a metrology challenge for optical microscopy tools by the opaque nature of silicon. Using infrared microscopy, silicon wafers become transparent to the near-infrared (NIR) wavelengths of the electromagnetic spectrum, enabling metrology at the interface of bonded wafer pairs. Wafers can be bonded face to face (F2F) or face to back (F2B) which the stacking direction is dictated by how the stacks are carried in the process and functionality required. For example, Memory stacks tend to use F2B stacking enables a better managed design. Current commercial tools use single image technique for F2F bonding overlay measurement because depth of focus is sufficient to include both surfaces; and use multiple image techniques for F2B overlay measurement application for the depth of focus is no longer sufficient to include both stacked wafer surfaces. There is a need to specify the Z coordinate or stacking wafer number through the silicon when visiting measurement wafer sites. Two shown images are of the same (X, Y) but separate Z location acquired at focus position of each wafer surface containing overlay marks. Usually the top surface image is bright and clear; however, the bottom surface image is somewhat darker and noisier as an adhesive layer is used in between to bond the silicon wafers. Thus the top and bottom surface images are further processed to achieve similar brightness and noise level before merged for overlay measurement. This paper presents a special overlay measurement technique, using the infrared differential interference contrast (DIC) microscopy technique to measure the F2B wafer bonding overlay by a single shot image. A pair of thinned wafers at 50 and 150 μm thickness is bonded on top of a carrier wafer to evaluate the bonding overlay. It works on the principle of interferometry to gain information about the

  15. Overlay control methodology comparison: field-by-field and high-order methods

    Science.gov (United States)

    Huang, Chun-Yen; Chiu, Chui-Fu; Wu, Wen-Bin; Shih, Chiang-Lin; Huang, Chin-Chou Kevin; Huang, Healthy; Choi, DongSub; Pierson, Bill; Robinson, John C.

    2012-03-01

    Overlay control in advanced integrated circuit (IC) manufacturing is becoming one of the leading lithographic challenges in the 3x and 2x nm process nodes. Production overlay control can no longer meet the stringent emerging requirements based on linear composite wafer and field models with sampling of 10 to 20 fields and 4 to 5 sites per field, which was the industry standard for many years. Methods that have emerged include overlay metrology in many or all fields, including the high order field model method called high order control (HOC), and field by field control (FxFc) methods also called correction per exposure. The HOC and FxFc methods were initially introduced as relatively infrequent scanner qualification activities meant to supplement linear production schemes. More recently, however, it is clear that production control is also requiring intense sampling, similar high order and FxFc methods. The added control benefits of high order and FxFc overlay methods need to be balanced with the increased metrology requirements, however, without putting material at risk. Of critical importance is the proper control of edge fields, which requires intensive sampling in order to minimize signatures. In this study we compare various methods of overlay control including the performance levels that can be achieved.

  16. Characterisation of hydrocarbonaceous overlayers important in metal-catalysed selective hydrogenation reactions

    Energy Technology Data Exchange (ETDEWEB)

    Lennon, David; Warringham, Robbie [School of Chemistry, Joseph Black Building, University of Glasgow, Glasgow G12 8QQ (United Kingdom); Guidi, Tatiana [ISIS Facility, STFC Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 0QX (United Kingdom); Parker, Stewart F., E-mail: stewart.parker@stfc.ac.uk [ISIS Facility, STFC Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 0QX (United Kingdom)

    2013-12-12

    Highlights: • Inelastic neutron scattering spectroscopy of a commercial dehydrogenation catalyst. • The overlayer present on the catalyst is predominantly aliphatic. • A population of strongly hydrogen bonded hydroxyls is also present. - Abstract: The hydrogenation of alkynes to alkenes over supported metal catalysts is an important industrial process and it has been shown that hydrocarbonaceous overlayers are important in controlling selectivity profiles of metal-catalysed hydrogenation reactions. As a model system, we have selected propyne hydrogenation over a commercial Pd(5%)/Al{sub 2}O{sub 3} catalyst. Inelastic neutron scattering studies show that the C–H stretching mode ranges from 2850 to 3063 cm{sup −1}, indicating the mostly aliphatic nature of the overlayer and this is supported by the quantification of the carbon and hydrogen on the surface. There is also a population of strongly hydrogen-bonded hydroxyls, their presence would indicate that the overlayer probably contains some oxygen functionality. There is little evidence for any olefinic or aromatic species. This is distinctly different from the hydrogen-poor overlayers that are deposited on Ni/Al{sub 2}O{sub 3} catalysts during methane reforming.

  17. Residual stress determination in a dissimilar weld overlay pipe by neutron diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Woo, Wanchuck, E-mail: chuckwoo@kaeri.re.kr [Neutron Science Division, Korea Atomic Energy Research Institute, Daejeon 305-353 (Korea, Republic of); Em, Vyacheslav [Neutron Science Division, Korea Atomic Energy Research Institute, Daejeon 305-353 (Korea, Republic of); Hubbard, Camden R. [Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Lee, Ho-Jin [Nuclear Materials Research Center, Korea Atomic Energy Research Institute, Daejeon 305-353 (Korea, Republic of); Park, Kwang Soo [Corporate R and D Institute, Doosan Heavy Industries and Construction, Changwon 641-792 (Korea, Republic of)

    2011-10-15

    Highlights: {yields} Determined residual stress distribution in a dissimilar weld overlay pipe. {yields} Consists of a ferritic (SA508), austenitic (F316L) steels, Alloy 182 consumable. {yields} Measured significant compression (-600 MPa) near the inner wall of overlay. {yields} Validate integrity of the inner wall for the pressurized nozzle nuclear structure. - Abstract: Residual stresses were determined through the thickness of a dissimilar weld overlay pipe using neutron diffraction. The specimen has a complex joining structure consisting of a ferritic steel (SA508), austenitic steel (F316L), Ni-based consumable (Alloy 182), and overlay of Ni-base superalloy (Alloy 52M). It simulates pressurized nozzle components, which have been a critical issue under the severe crack condition of nuclear power reactors. Two neutron diffractometers with different spatial resolutions have been utilized on the identical specimen for comparison. The macroscopic 'stress-free' lattice spacing (d{sub o}) was also obtained from both using a 2-mm width comb-like coupon. The results show significant changes in residual stresses from tension (300-400 MPa) to compression (-600 MPa) through the thickness of the dissimilar weld overlay pipe specimen.

  18. Design and development of a mobile image overlay system for needle interventions.

    Science.gov (United States)

    Anand, M; King, F; Ungi, T; Lasso, A; Rudan, J; Jayender, J; Fritz, J; Carrino, J A; Jolesz, F A; Fichtinger, G

    2014-01-01

    Previously, a static and adjustable image overlay systems were proposed for aiding needle interventions. The system was either fixed to a scanner or mounted over a large articulated counterbalanced arm. Certain drawbacks associated with these systems limited the clinical translation. In order to minimize these limitations, we present the mobile image overlay system with the objective of reduced system weight, smaller dimension, and increased tracking accuracy. The design study includes optimal workspace definition, selection of display device, mirror, and laser source. The laser plane alignment, phantom design, image overlay plane calibration, and system accuracy validation methods are discussed. The virtual image is generated by a tablet device and projected into the patient by using a beamsplitter mirror. The viewbox weight (1.0 kg) was reduced by 8.2 times and image overlay plane tracking precision (0.21 mm, STD = 0.05) was improved by 5 times compared to previous system. The automatic self-calibration of the image overlay plane was achieved in two simple steps and can be done away from patient table. The fiducial registration error of the physical phantom to scanned image volume registration was 1.35 mm (STD = 0.11). The reduced system weight and increased accuracy of optical tracking should enable the system to be hand held by the physician and explore the image volume over the patient for needle interventions.

  19. Image based overlay measurement improvements of 28nm FD-SOI CMOS front-end critical steps

    Science.gov (United States)

    Dettoni, F.; Shapoval, T.; Bouyssou, R.; Itzkovich, T.; Haupt, R.; Dezauzier, C.

    2017-03-01

    Technology shrinkage leads to tight specifications in advanced semiconductor industries. For several years', metrology for lithography has been a key technology to address this challenge and to improve yield. More specifically overlay metrology is the object of special attention for tool suppliers and semiconductor manufacturers. This work focuses on Image Based Overlay (IBO) metrology for 28 nm FD-SOI CMOS front-end critical steps (gate and contact). With Overlay specifications below 10 nm, accuracy of the measurement is critical. In this study we show specific cases where target designs need to be optimized in order to minimize process effects (CMP, etch, deposition, etc.) that could lead to overlay measurement errors. Another important aspect of the metrology target is that its design must be device-like in order to better control and correct overlay errors leading to yield loss. Methodologies to optimize overlay metrology recipes are also presented. If the process effects cannot be removed entirely by target design optimization, recipe parameters have to be carefully chosen and controlled to minimize the influence of the target imperfection on measured overlay. With target asymmetry being one of the main contributors to those residual overlay measurement errors the Qmerit accuracy flag can be used to quantify the measurement error and recipe parameters can be set accordingly in order to minimize the target asymmetry impact. Reference technique measurements (CD-SEM) were used to check accuracy of the optimized overlay measurements.

  20. Weld overlay coatings for erosion control. Task A: Literature review, progress report

    Energy Technology Data Exchange (ETDEWEB)

    Levin, B.; DuPont, J.N.; Marder, A.R.

    1993-03-03

    A literature review was made. In spite of similarities between abrasive wear and solid particle erosion, weld overlay hardfacing alloys that exhibit high abrasion resistance may not necessarily have good erosion resistance. The performance of weld overlay hardfacing alloys in erosive environments has not been studied in detail. It is believed that primary-solidified hard phases such as carbides and intermetallic compounds have a strong influence on erosion resistance of weld overlay hardfacing alloys. However, relationships between size, shape, and volume fraction of hard phases in a hardfacing alloys and erosion resistance were not established. Almost all hardfacing alloys can be separated into two major groups based upon chemical compositions of the primary solidified hard phases: (a) carbide hardening alloys (Co-base/carbide, WC-Co and some Fe base superalloys); and (b) intermetallic hardening alloys (Ni-base alloys, austenitic steels, iron-aluminides).

  1. Residual stress determination in an overlay dissimilar welded pipe by neutron diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Woo, Wan Chuck [ORNL; Em, Vyacheslav [Korea Atomic Energy Research Institute; Hubbard, Camden R [ORNL; Lee, Ho-Jin [Korea Atomic Energy Research Institute; Park, Kwang Soo [Doosan Heavy Industries & Construction

    2011-01-01

    Residual stresses were determined through the thickness of a dissimilar weld overlay pipe using neutron diffraction. The specimen has a complex joining structure consisting of a ferritic steel (SA508), austenitic steel (F316L), Ni-based consumable (Alloy 182), and overlay of Ni-base superalloy (Alloy 52M). It simulates pressurized nozzle components, which have been a critical issue under the severe crack condition of nuclear power reactors. Two neutron diffractometers with different spatial resolutions have been utilized on the identical specimen for comparison. The macroscopic 'stress-free' lattice spacing (d{sub o}) was also obtained from both using a 2-mm width comb-like coupon. The results show significant changes in residual stresses from tension (300-400 MPa) to compression (-600 MPa) through the thickness of the dissimilar weld overlay pipe specimen.

  2. Studying protein-protein interactions via blot overlay/far western blot.

    Science.gov (United States)

    Hall, Randy A

    2015-01-01

    Blot overlay is a useful method for studying protein-protein interactions. This technique involves fractionating proteins on SDS-PAGE, blotting to nitrocellulose or PVDF membrane, and then incubating with a probe of interest. The probe is typically a protein that is radiolabeled, biotinylated, or simply visualized with a specific antibody. When the probe is visualized via antibody detection, this technique is often referred to as "Far Western blot." Many different kinds of protein-protein interactions can be studied via blot overlay, and the method is applicable to screens for unknown protein-protein interactions as well as to the detailed characterization of known interactions.

  3. Development of a New Geospatial Data Sharing/overlay System for Land Environmental Studies - Ceres GAIA -

    Science.gov (United States)

    Tateishi, R.; Sri Sumantyo, J. T.; Miyazaki, A.; Sumitani, H.

    2012-07-01

    A new geospatial data sharing/overlay system, CEReS Gaia, has developed. The purpose of the system development is to promote land surface environmental studies. The system has developed to meet the requirements by academic users who wish easy data analysis by using his/her own data with existing other data. The system has the following features; a) internationally unlimited expansion of servers, b) multi-language capability (currently, only English), c) free access without user registration, d) data upload/download by registered users, e) capability to overlay user's data on other registered data, f) option of open or selective data distribution.

  4. Performance Evaluation of Cognitive Interference Channels Using a Spectrum Overlay Strategy

    Science.gov (United States)

    Knoblock, Eric J.

    2018-01-01

    The use of cognitive radios (CR) and cooperative communications techniques may assist in interference mitigation via sensing of the environment and dynamically altering communications parameters through the use of various mechanisms - one of which is the overlay technique. This report provides a performance analysis of an interference channel with a cognitive transceiver operating in an overlay configuration to evaluate the gains from using cognition. As shown in this report, a cognitive transceiver can simultaneously share spectrum while enhancing performance of non-cognitive nodes via knowledge of the communications channel as well as knowledge of neighboring users' modulation and coding schemes.

  5. Description of the signal and background event mixing as implemented in the Marlin processor OverlayTiming

    CERN Document Server

    Schade, P

    2011-01-01

    This note documents OverlayTiming, a processor in the Marlin software frame- work. OverlayTiming can model the timing structure of a linear collider bunch train and offers the possibility to merge simulated physics events with beam-beam background events. In addition, a realistic structure of the detector readout can be imitated by defining readout time windows for each subdetector.

  6. A comparative study of three commonly used two-dimensional overlay generation methods in bite mark analysis.

    Science.gov (United States)

    Pajnigara, Nilufer Gev; Balpande, Apeksha S; Motwani, Mukta B; Choudhary, Anuraag; Thakur, Samantha; Pajnigara, Natasha G

    2017-01-01

    The present study attempts to compare the bite mark overlays generated by three different methods. The objectives of the study were to compare the three commonly used techniques for overlay generation and to evaluate the interobserver reliability in assessing bite marks by these methods. Overlays were produced from the biting surfaces of six upper and six lower anterior teeth of 30 dental study models using the following three methods: (a) Hand tracing from wax impressions, (b) radiopaque impression method and (c) computer-based method. The computer-based method was found to be the most accurate method. Of the two hand tracing methods, radiopaque wax impression method was better than the wax impression method for overlay generation. It is recommended that forensic odontologists use computerized method, but the use of hand tracing overlays in bite mark comparison cases using radiopaque wax impression method can also be done where sophisticated software and trained persons in forensic odontology are not available.

  7. First principles analysis of hydrogen chemisorption on Pd-Re alloyed overlayers and alloyed surfaces

    DEFF Research Database (Denmark)

    Pallassana, Venkataraman; Neurock, Matthew; Hansen, Lars Bruno

    2000-01-01

    Gradient corrected periodic density functional theory (DFT-GGA) slab calculations were used to examine the chemisorption of atomic hydrogen on various Pd-Re alloyed overlayers and uniformly alloyed surfaces. Adsorption was examined at 33% surface coverage, where atomic hydrogen preferred the thre...

  8. Assessing the Crossdisciplinarity of Technology-Enhanced Learning with Science Overlay Maps and Diversity Measures

    Science.gov (United States)

    Kalz, Marco; Specht, Marcus

    2014-01-01

    This paper deals with the assessment of the crossdisciplinarity of technology-enhanced learning (TEL). Based on a general discussion of the concept interdisciplinarity and a summary of the discussion in the field, two empirical methods from scientometrics are introduced and applied. Science overlay maps and the Rao-Stirling diversity index are…

  9. Posterior open occlusion management by registration of overlay removable partial denture: A clinical report.

    Science.gov (United States)

    Nosouhian, Saeid; Davoudi, Amin; Derhami, Mohammad

    2015-01-01

    This clinical report describes prosthetic rehabilitation of posterior open bite relationship in a patient with several missing teeth and skeletal Class III malocclusion. Primary diagnostic esthetic evaluations were performed by mounting casts in centric relation and estimating lost vertical dimension of occlusion. Exclusive treatments were designated by applying overlay removable partial denture with external attachment systems for higher retentions.

  10. Posterior open occlusion management by registration of overlay removable partial denture: A clinical report

    OpenAIRE

    Saeid Nosouhian; Amin Davoudi; Mohammad Derhami

    2015-01-01

    This clinical report describes prosthetic rehabilitation of posterior open bite relationship in a patient with several missing teeth and skeletal Class III malocclusion. Primary diagnostic esthetic evaluations were performed by mounting casts in centric relation and estimating lost vertical dimension of occlusion. Exclusive treatments were designated by applying overlay removable partial denture with external attachment systems for higher retentions.

  11. Posterior open occlusion management by registration of overlay removable partial denture: A clinical report

    Directory of Open Access Journals (Sweden)

    Saeid Nosouhian

    2015-01-01

    Full Text Available This clinical report describes prosthetic rehabilitation of posterior open bite relationship in a patient with several missing teeth and skeletal Class III malocclusion. Primary diagnostic esthetic evaluations were performed by mounting casts in centric relation and estimating lost vertical dimension of occlusion. Exclusive treatments were designated by applying overlay removable partial denture with external attachment systems for higher retentions.

  12. Condition of concrete overlays on Route 60 over Lynnhaven Inlet after 10 years.

    Science.gov (United States)

    2009-01-01

    In 1996, 16 high performance concrete overlays were placed on two 28-span bridges on Route 60 over the Lynnhaven Inlet in Virginia Beach, Virginia. Thirteen concrete mixtures included a variety of combinations of silica fume (SF), fly ash, slag, late...

  13. Interactive overlay maps for US Patent (USPTO) data based on International Patent Classifications (IPC)

    NARCIS (Netherlands)

    Leydesdorff, L.; Kushnir, D.; Rafols, I.

    2014-01-01

    We report on the development of an interface to the US Patent and Trademark Office (USPTO) that allows for the mapping of patent portfolios as overlays to basemaps constructed from citation relations among all patents contained in this database during the period 1976-2011. Both the interface and the

  14. Robotic weld overlay coatings for erosion control. Final technical progress report, July 1992--July 1995

    Energy Technology Data Exchange (ETDEWEB)

    Levin, B.F.; DuPont, J.N.; Marder, A.R.

    1995-10-15

    The erosion behavior of weld overlay coatings has been studied. Eleven weld overlay alloys were deposited on 1018 steel substrates using the plasma arc welding process and erosion tested at 400{degrees}C at 90{degrees} and 30{degrees} particle impact angles. The microstructure of each coating was characterized before erosion testing. A relative ranking of the coatings erosion resistance was developed by determining the steady state erosion rates. Ultimet, Inconel-625, and 316L SS coatings showed the best erosion resistance at both impact angles. It was found that weld overlays that exhibit good abrasion resistance did not show good erosion resistance. Erosion tests were also performed for selected wrought materials with chemical composition similar to weld overlays. Eroded surfaces of the wrought and weld alloys were examined by Scanning Electron Microscopy (SEM). Microhardness tests were performed on the eroded samples below the erosion surface to determine size of the plastically deformed region. It was found that one group of coatings experienced significant plastic deformation as a result of erosion while the other did not. It was also established that, in the steady state erosion regime, the size of the plastically deformed region is constant.

  15. Shadow Segmentation and Augmentation Using á-overlay Models that Account for Penumbra

    DEFF Research Database (Denmark)

    Nielsen, Michael; Madsen, Claus B.

    2006-01-01

    that an augmented virtual object can cast an exact shadow. The penumbras (half-shadows) must be taken into account so that we can model the soft shadows.We hope to achieve this by modelling the shadow regions (umbra and penumbra alike) with a transparent overlay. This paper reviews the state-of-the-art shadow...

  16. Arbitration Intervention Worker (AIW) Services: Case Management Overlay in a Juvenile Diversion Program

    Science.gov (United States)

    Poythress, Norman G.; Dembo, Richard; DuDell, Gary; Wareham, Jennifer

    2006-01-01

    In this issue we describe a clinical trials study of the impact of adding specific case manager overlay services to "treatment as usual" services for youths in a Juvenile Arbitration Program. In this first article we describe the experimental intervention, the Arbitration Intervention Worker (AIW) service, which was provided to a randomly selected…

  17. The Effects of Letter Spacing and Coloured Overlays on Reading Speed and Accuracy in Adult Dyslexia

    Science.gov (United States)

    Sjoblom, Amanda M.; Eaton, Elizabeth; Stagg, Steven D.

    2016-01-01

    Background: Zorzi et al. (2012, Proc. Natl. Acad. Sci. U.S.A., 109, 11455) found evidence that extra-large letter spacing aids children with dyslexia, but the evidence for the coloured overlays is contradictory (e.g., Henderson et al., 2013, "J. Res. Special Educ. Needs," 13, 57; Wilkins, 2002, "Ophthalmic Physiol. Opt.," 22,…

  18. Evaluation of a conventional chip seal under an overlay to mitigate reflective cracking (informal).

    Science.gov (United States)

    2015-03-01

    The Billings District initiated an experimental project in placing a conventional : chip seal (as an interlayer) on an existing pavement prior to an overlay : (composed of a 0.25 PMS thickness). The intent of the chip seal (CS) was to : seal exist...

  19. Fluorogenic membrane overlays to enumerate total coliforms, Escherichia coli, and total Vibrionaceae in shellfish and seawater

    Science.gov (United States)

    Three assays were developed to enumerate total coliforms, Escherichia coli, and total Vibrionaceae in shellfish and other foods and in seawater and other environmental samples. Assays involve membrane overlays of overnight colonies on non-selective agar plates to detect ß-glucuronidase and lysyl am...

  20. Heavy Vehicle Simulator aided evaluation of overlays on pavements with active cracks

    CSIR Research Space (South Africa)

    Viljoen, AW

    1987-07-01

    Full Text Available their effects by means of field data from actual pavements. The South African Heavy Simulator was also used to evaluate a variety of conventional and innovative asphaltic overlays on a severely cracked concrete pavement of which the mechanisms and extent...

  1. Science overlay maps: a new tool for research policy and library management

    NARCIS (Netherlands)

    Rafols, I.; Porter, A.L.; Leydesdorff, L.

    2010-01-01

    We present a novel approach to visually locate bodies of research within the sciences, both at each moment of time and dynamically. This article describes how this approach fits with other efforts to locally and globally map scientific outputs. We then show how these science overlay maps help

  2. Posterior open occlusion management by registration of overlay removable partial denture: A clinical report

    Science.gov (United States)

    Nosouhian, Saeid; Davoudi, Amin; Derhami, Mohammad

    2015-01-01

    This clinical report describes prosthetic rehabilitation of posterior open bite relationship in a patient with several missing teeth and skeletal Class III malocclusion. Primary diagnostic esthetic evaluations were performed by mounting casts in centric relation and estimating lost vertical dimension of occlusion. Exclusive treatments were designated by applying overlay removable partial denture with external attachment systems for higher retentions. PMID:26929544

  3. Overlay excursion management through sample plan optimization and cycle time reduction

    Science.gov (United States)

    Chen, Xuemei; Hung, Ming-Yeon; Kuo, Kelly; Fu, Steven; Shanthikumar, Geoge; Mao, Zhoujie; Deng, Shiming; Hazari, Viral; Monahan, Kevin M.; Slessor, Mike D.; Lev, Amir

    2003-05-01

    As fabs transition from 200 to 300mm wafers with shrinking design rules, the risk and cost associated with overlay excursions become more severe. This significantly impacts the overall litho-cell efficiency. Effective detection, identification, and reduction of overlay excursions are essential for realizing the productivity and cost benefits of the technology shifts. We have developed a comprehensive overlay excursion management method that encompasses baseline variation analysis, statistical separation and characterization of excursion signatures and their frequencies, as well as selection of sampling plans and control methods that minimize material at risk due to excursion. A novel baseline variance estimation method is developed that takes into account the spatial signature and temporal behavior of the litho-cell overlay correction mechanisms. Spatial and temporal excursion signatures are identified and incorporated in a cost model that estimates the material at risk in an excursion cycle. The material at risk associated with various sampling plans, control charts, and cycle times is assessed considering various lot disposition and routing decisions. These results are then used in determining an optimal sampling and control strategy for effective excursion management. In this paper, we describe and demonstrate the effectiveness of the methods using actual 300mm fab overlay data from several critical layers. With a thorough assessment of the actual baseline and excursion distributions, we quantify the amount of wafer-to-wafer and within-wafer sampling necessary for detecting excursions with minimal material at risk. We also evaluate the impact of shorter cycle time and faster response to excursion, which is made possible through automation and alternative metrology configurations.

  4. From Geo-Social to Geo-Local: The Flows and Biases of Volunteered Geographic Information

    Science.gov (United States)

    Stephens, Monica

    2012-01-01

    This dissertation analyzes the geography of information in the 21st century where BigData, social networks, user generated production of content and geography combine to create new and complex patterns of space, context and sociability. Both online and offline, social networks are creating a space that simultaneously unifies individuals and…

  5. Generic Network Location Service

    Directory of Open Access Journals (Sweden)

    Laban Mwansa

    2010-11-01

    Full Text Available This work presents the Generic Network Location Service based on the Chord implementation utilizing data structures called distributed hash tables (DHT or structured overlay networks, which are used to build scalable self-managing distributed systems. The provided algorithms guarantee resilience in the presence of dynamism: they guarantee consistent lookup results in the presence of nodes failing and leaving. Generic Network Location Service provides a Location Service system based on DHT technology, which is storing device location records in nodes within a Chord DHT. Location records are consisting of network device identification keys as attributes, which are used to create replicas of additional location records through established Chord hashing mechanisms. Storing device location records, in places address-able (using the DHT lookup by individual location record keys provides a simple way of implementing transla¬tion functions similar to well¬ known network services (e.g. ARP, DNS, ENUM. The generic network location ser¬vice presented in the paper is not supposed to be a substitu¬tion of the existing translation techniques (e.g. ARP, DNS, ENUM, but it is considered as an overlay service that uses data available in existing systems and provides some translations currently unavailable.

  6. Fundamental structures of dynamic social networks

    DEFF Research Database (Denmark)

    Sekara, Vedran; Stopczynski, Arkadiusz; Jørgensen, Sune Lehmann

    2016-01-01

    , and the productivity of teams. Although there has been much progress on understanding complex networks over the past decade, little is known about the regularities governing the microdynamics of social networks. Here, we explore the dynamic social network of a densely-connected population of ∼1,000 individuals...... and their interactions in the network of real-world person-to-person proximity measured via Bluetooth, as well as their telecommunication networks, online social media contacts, geolocation, and demographic data. These high-resolution data allow us to observe social groups directly, rendering community detection...... a pattern of recurring meetings across weeks and months, each with varying degrees of regularity. Taken together, these findings provide a powerful simplification of the social network, where cores represent fundamental structures expressed with strong temporal and spatial regularity. Using this framework...

  7. An Ubiquitous and Non Intrusive System for Pervasive Advertising using NFC and Geolocation Technologies and Air Hand Gestures

    Directory of Open Access Journals (Sweden)

    Francisco M. Borrego-Jaraba

    2014-01-01

    Full Text Available In this paper we present a pervasive proposal for advertising using mobile phones, Near Field Communication, geolocation and air hand gestures. Advertising post built by users in public/private spaces can store multiple ads containing any kind of textual, graphic or multimedia information. Ads are automatically shows in the mobile phone of the users using a notification based process considering relative user location between the posts and the user preferences. Moreover, ads can be stored and retrieved from the post using hand gestures and Near Field Communication technology. Secure management of information about users, posts, and notifications and the use of instant messaging enable the development of systems to extend the current advertising strategies based on Web, large displays or digital signage.

  8. ATLAS simulation using real data: Embedding and overlay

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00053405; The ATLAS collaboration

    2017-01-01

    For some physics processes studied with the ATLAS detector, a more accurate simulation in some respects can be achieved by including real data into simulated events, with substantial potential improvements in the CPU, disk space, and memory usage of the standard simulation configuration, at the cost of significant database and networking challenges. Real proton-proton background events can be overlaid (at the detector digitization output stage) on a simulated hard-scatter process, to account for pileup background (from nearby bunch crossings), cavern background, and detector noise. A similar method is used to account for the large underlying event from heavy ion collisions, rather than directly simulating the full collision. Embedding replaces the muons found in Z→μμ decays in data with simulated taus at the same 4-momenta, thus preserving the underlying event and pileup from the original data event. In all these cases, care must be taken to exactly match detector conditions (beamspot, magnetic fields, al...

  9. ATLAS Simulation using Real Data: Embedding and Overlay

    CERN Document Server

    Haas, Andy; The ATLAS collaboration

    2016-01-01

    For some physics processes studied with the ATLAS detector, a more accurate simulation in some respects can be achieved by including real data into simulated events, with substantial potential improvements in the CPU, disk space, and memory usage of the standard simulation configuration, at the cost of significant database and networking challenges. Real proton-proton background events can be overlaid (at the detector digitization output stage) on a simulated hard-scatter process, to account for pileup background (from nearby bunch crossings), cavern background, and detector noise. A similar method is used to account for the large underlying event from heavy ion collisions, rather than directly simulating the full collision. Embedding replaces the muons found in Z->mumu decays in data with simulated taus at the same 4-momenta, thus preserving the underlying event and pileup from the original data event. In all these cases, care must be taken to exactly match detector conditions (beamspot, magnetic fields, ali...

  10. SENSING SLOW MOBILITY AND INTERESTING LOCATIONS FOR LOMBARDY REGION (ITALY: A CASE STUDY USING POINTWISE GEOLOCATED OPEN DATA

    Directory of Open Access Journals (Sweden)

    M. A. Brovelli

    2016-06-01

    Full Text Available During the past years Web 2.0 technologies have caused the emergence of platforms where users can share data related to their activities which in some cases are then publicly released with open licenses. Popular categories for this include community platforms where users can upload GPS tracks collected during slow travel activities (e.g. hiking, biking and horse riding and platforms where users share their geolocated photos. However, due to the high heterogeneity of the information available on the Web, the sole use of these user-generated contents makes it an ambitious challenge to understand slow mobility flows as well as to detect the most visited locations in a region. Exploiting the available data on community sharing websites allows to collect near real-time open data streams and enables rigorous spatial-temporal analysis. This work presents an approach for collecting, unifying and analysing pointwise geolocated open data available from different sources with the aim of identifying the main locations and destinations of slow mobility activities. For this purpose, we collected pointwise open data from the Wikiloc platform, Twitter, Flickr and Foursquare. The analysis was confined to the data uploaded in Lombardy Region (Northern Italy – corresponding to millions of pointwise data. Collected data was processed through the use of Free and Open Source Software (FOSS in order to organize them into a suitable database. This allowed to run statistical analyses on data distribution in both time and space by enabling the detection of users’ slow mobility preferences as well as places of interest at a regional scale.

  11. Recovery of Bennu's orientation for the OSIRIS-REx mission: implications for the spin state accuracy and geolocation errors

    Science.gov (United States)

    Mazarico, Erwan; Rowlands, David D.; Sabaka, Terence J.; Getzandanner, Kenneth M.; Rubincam, David P.; Nicholas, Joseph B.; Moreau, Michael C.

    2017-10-01

    The goal of the OSIRIS-REx mission is to return a sample of asteroid material from near-Earth asteroid (101955) Bennu. The role of the navigation and flight dynamics team is critical for the spacecraft to execute a precisely planned sampling maneuver over a specifically selected landing site. In particular, the orientation of Bennu needs to be recovered with good accuracy during orbital operations to contribute as small an error as possible to the landing error budget. Although Bennu is well characterized from Earth-based radar observations, its orientation dynamics are not sufficiently known to exclude the presence of a small wobble. To better understand this contingency and evaluate how well the orientation can be recovered in the presence of a large 1° wobble, we conduct a comprehensive simulation with the NASA GSFC GEODYN orbit determination and geodetic parameter estimation software. We describe the dynamic orientation modeling implemented in GEODYN in support of OSIRIS-REx operations and show how both altimetry and imagery data can be used as either undifferenced (landmark, direct altimetry) or differenced (image crossover, altimetry crossover) measurements. We find that these two different types of data contribute differently to the recovery of instrument pointing or planetary orientation. When upweighted, the absolute measurements help reduce the geolocation errors, despite poorer astrometric (inertial) performance. We find that with no wobble present, all the geolocation requirements are met. While the presence of a large wobble is detrimental, the recovery is still reliable thanks to the combined use of altimetry and imagery data.

  12. An Efficient Vector-Raster Overlay Algorithm for High-Accuracy and High-Efficiency Surface Area Calculations of Irregularly Shaped Land Use Patches

    Directory of Open Access Journals (Sweden)

    Peng Xie

    2017-05-01

    Full Text Available The Earth’s surface is uneven, and conventional area calculation methods are based on the assumption that the projection plane area can be obtained without considering the actual undulation of the Earth’s surface and by simplifying the Earth’s shape to be a standard ellipsoid. However, the true surface area is important for investigating and evaluating land resources. In this study, the authors propose a new method based on an efficient vector-raster overlay algorithm (VROA-based method to calculate the surface areas of irregularly shaped land use patches. In this method, a surface area raster file is first generated based on the raster-based digital elevation model (raster-based DEM. Then, a vector-raster overlay algorithm (VROA is used that considers the precise clipping of raster cells using the vector polygon boundary. Xiantao City, Luotian County, and the Shennongjia Forestry District, which are representative of a plain landform, a hilly topography, and a mountain landscape, respectively, are selected to calculate the surface area. Compared with a traditional method based on triangulated irregular networks (TIN-based method, our method significantly reduces the processing time. In addition, our method effectively improves the accuracy compared with another traditional method based on raster-based DEM (raster-based method. Therefore, the method satisfies the requirements of large-scale engineering applications.

  13. Efficient star-topology solving local minima for geolocation in real UMTS networks: an experimental assessment with real data

    DEFF Research Database (Denmark)

    García-Fernández, Juan Antonio; Jurado-Navas, Antonio; Fernández-Navarro, Mariano

    2015-01-01

    Hyperbolic radio-location systems possess intrinsic uncertainty that depends on the Node B stations geometry when an iterative positioning algorithm like for instance, Levenberg–Marquardt,is employed to determine an estimate of the mobile station position. This inherent uncertainty arises from...... of avoiding any local minima. In this manner, errors in the positioning algorithm are only due to multipath environment and co-channel interference, ensuring that local minima do not affect the result offered by the positioning method. A provisional patent application based on this method has been filed...

  14. A novel approach for latent print identification using accurate overlays to prioritize reference prints.

    Science.gov (United States)

    Gantz, Daniel T; Gantz, Donald T; Walch, Mark A; Roberts, Maria Antonia; Buscaglia, JoAnn

    2014-12-01

    A novel approach to automated fingerprint matching and scoring that produces accurate locally and nonlinearly adjusted overlays of a latent print onto each reference print in a corpus is described. The technology, which addresses challenges inherent to latent prints, provides the latent print examiner with a prioritized ranking of candidate reference prints based on the overlays of the latent onto each candidate print. In addition to supporting current latent print comparison practices, this approach can make it possible to return a greater number of AFIS candidate prints because the ranked overlays provide a substantial starting point for latent-to-reference print comparison. To provide the image information required to create an accurate overlay of a latent print onto a reference print, "Ridge-Specific Markers" (RSMs), which correspond to short continuous segments of a ridge or furrow, are introduced. RSMs are reliably associated with any specific local section of a ridge or a furrow using the geometric information available from the image. Latent prints are commonly fragmentary, with reduced clarity and limited minutiae (i.e., ridge endings and bifurcations). Even in the absence of traditional minutiae, latent prints contain very important information in their ridges that permit automated matching using RSMs. No print orientation or information beyond the RSMs is required to generate the overlays. This automated process is applied to the 88 good quality latent prints in the NIST Special Database (SD) 27. Nonlinear overlays of each latent were produced onto all of the 88 reference prints in the NIST SD27. With fully automated processing, the true mate reference prints were ranked in the first candidate position for 80.7% of the latents tested, and 89.8% of the true mate reference prints ranked in the top ten positions. After manual post-processing of those latents for which the true mate reference print was not ranked first, these frequencies increased to 90

  15. OMI/Aura Level 1B VIS Global Geolocated Earth Shine Radiances 1-orbit L2 Swath 13x24 km V003 (OML1BRVG) at GES DISC

    Data.gov (United States)

    National Aeronautics and Space Administration — The Aura Ozone Monitoring Instrument (OMI) Level-1B (L1B) Geo-located Earth View VIS Radiance, Global-Mode (OML1BRVG) Version-3 product is now available to public...

  16. Combined Conjunctival Autograft and Overlay Amniotic Membrane Transplantation; a Novel Surgical Treatment for Pterygium

    Directory of Open Access Journals (Sweden)

    Siamak Zarei Ghanavati

    2014-01-01

    Full Text Available The authors report the long-term results of combined conjunctival autograft and overlay amniotic membrane transplantation (AMT for treatment of pterygium as a new surgical technique. Nineteen patients including 12 male and 7 female subjects with pterygium (primary, 14 cases; recurrent, 5 cases underwent combined conjunctival autograft and overlay AMT and were followed from 10 to 26 months. Mean age was 44.21±12.49 (range, 29.0-73.0 years. In one patient with grade T3 primary pterygium, the lesion recurred (5.2%, recurrence rate. No intra-and postoperative complication developed. This procedure seems a safe and effective surgical technique for pterygium treatment. Protection of the ocular surface during the early postoperative period reduces the friction-induced inflammation and might be helpful to prevent the recurrence.

  17. Combined conjunctival autograft and overlay amniotic membrane transplantation; a novel surgical treatment for pterygium.

    Science.gov (United States)

    Ghanavati, Siamak Zarei; Shousha, Mohamed Abou; Betancurt, Carolina; Perez, Victor L

    2014-01-01

    The authors report the long-term results of combined conjunctival autograft and overlay amniotic membrane transplantation (AMT) for treatment of pterygium as a new surgical technique. Nineteen patients including 12 male and 7 female subjects with pterygium (primary, 14 cases; recurrent, 5 cases) underwent combined conjunctival autograft and overlay AMT and were followed from 10 to 26 months. Mean age was 44.21±12.49 (range, 29.0-73.0) years. In one patient with grade T3 primary pterygium, the lesion recurred (5.2%, recurrence rate). No intra-and postoperative complication developed. This procedure seems a safe and effective surgical technique for pterygium treatment. Protection of the ocular surface during the early postoperative period reduces the friction-induced inflammation and might be helpful to prevent the recurrence.

  18. Impact of organic overlayers on a-Si:H/c-Si surface potential

    KAUST Repository

    Seif, Johannes P.

    2017-04-11

    Bilayers of intrinsic and doped hydrogenated amorphous silicon, deposited on crystalline silicon (c-Si) surfaces, simultaneously provide contact passivation and carrier collection in silicon heterojunction solar cells. Recently, we have shown that the presence of overlaying transparent conductive oxides can significantly affect the c-Si surface potential induced by these amorphous silicon stacks. Specifically, deposition on the hole-collecting bilayers can result in an undesired weakening of contact passivation, thereby lowering the achievable fill factor in a finished device. We test here a variety of organic semiconductors of different doping levels, overlaying hydrogenated amorphous silicon layers and silicon-based hole collectors, to mitigate this effect. We find that these materials enhance the c-Si surface potential, leading to increased implied fill factors. This opens opportunities for improved device performance.

  19. Automatic Generation of Overlays and Offset Values Based on Visiting Vehicle Telemetry and RWS Visuals

    Science.gov (United States)

    Dunne, Matthew J.

    2011-01-01

    The development of computer software as a tool to generate visual displays has led to an overall expansion of automated computer generated images in the aerospace industry. These visual overlays are generated by combining raw data with pre-existing data on the object or objects being analyzed on the screen. The National Aeronautics and Space Administration (NASA) uses this computer software to generate on-screen overlays when a Visiting Vehicle (VV) is berthing with the International Space Station (ISS). In order for Mission Control Center personnel to be a contributing factor in the VV berthing process, computer software similar to that on the ISS must be readily available on the ground to be used for analysis. In addition, this software must perform engineering calculations and save data for further analysis.

  20. Problems with using overlay mapping for planning and their implications for geographic information systems

    Science.gov (United States)

    Bailey, Robert G.

    1988-01-01

    As part of the planning process, maps of natural factors are often superimposed in order to identify areas which are suitable or unsuitable for a particular type of resource management. Overlay maps may also be used to identify analysis areas for predictive modeling of resource productivity and ecological response to management. Current interest in applying computer-assisted mapping technology to making overlay maps is drawing attention to geographic information systems for this purpose. The resultant maps, however, may be so inaccurate or unable to capture significant units of productivity and ecological response that they could lead to imperfect or false conclusions. Recommendations are made on how to proceed in light of these problems.

  1. Clinical Applications of a CT Window Blending Algorithm: RADIO (Relative Attenuation-Dependent Image Overlay).

    Science.gov (United States)

    Mandell, Jacob C; Khurana, Bharti; Folio, Les R; Hyun, Hyewon; Smith, Stacy E; Dunne, Ruth M; Andriole, Katherine P

    2017-06-01

    A methodology is described using Adobe Photoshop and Adobe Extendscript to process DICOM images with a Relative Attenuation-Dependent Image Overlay (RADIO) algorithm to visualize the full dynamic range of CT in one view, without requiring a change in window and level settings. The potential clinical uses for such an algorithm are described in a pictorial overview, including applications in emergency radiology, oncologic imaging, and nuclear medicine and molecular imaging.

  2. RESTORING A DAMAGED 16-YEAR -OLD INSULATING POLYMER CONCRETE DIKE OVERLAY: REPAIR MATERIALS AND TECHNOLOGIES.

    Energy Technology Data Exchange (ETDEWEB)

    SUGAMA,T.

    2007-01-01

    The objective of this program was to design and formulate organic polymer-based material systems suitable for repairing and restoring the overlay panels of insulating lightweight polymer concrete (ILPC) from the concrete floor and slope wall of a dike at KeySpan liquefied natural gas (LNG) facility in Greenpoint, Brooklyn, NY, just over sixteen years ago. It also included undertaking a small-scale field demonstration to ensure that the commercial repairing technologies were applicable to the designed and formulated materials.

  3. Abrasive Wear Resistance of Overlay Composite Alloy with Addition of Carbide Powders

    OpenAIRE

    Tadao, ARAKI; Minoru, NISHIDA; Akio, HIROSE; Kouji, YANO; HIroshi, FUJITA; Faculty of Eng., Ehime University; Faculty of Eng., Ehime University; Faculty of Eng., Osaka University; Kawasaki Steel Co., Ltd.; Tokuden Co., Ltd.

    1993-01-01

    The overall objective of this project is to provide data showing how carbide powder in addition to base alloy powder can be used effectively to increase hardness of overlay alloy and resistance to abrasive wear. An experimental study was performed to examine combinations of base alloy powders and reinforcing powders. The base alloy powders considered were stainless steel, Ni-base alloy, Co-base alloy and high speed steel powder, while reinforcing powders considered were metal-carbide and cera...

  4. Ellipsometric study of ambient-produced overlayer growth rate on YBa2Cu3O(7-x) films

    Science.gov (United States)

    Sieg, Robert M.; Alterovitz, Samuel A.; Warner, Joseph D.

    1993-01-01

    An ellipsometric study of ambient-reaction-produced BaCO3 overlayer growth on laser-ablated YBCO is presented as a function of time. The effects of the anisotropy of YBCO on the ellipsometric data inversion process are discussed, and it is concluded that with certain restrictions on the data acquisition method, the anisotropic substrate can be adequately modeled by its isotropic pseudodielectric function for the purpose of overlayer thickness estimation. It is found that after an initial period of rapid growth attributed to the chemical reaction of the exposed surface bonds, the BaCO3 overlayer growth is linear at 1-2 A per day. This slow growth rate is attributed to the complexity of the BaCO3-forming reaction, together with the need for ambient reactants to diffuse through the overlayer.

  5. Texas flexible pavements and overlays : interim report for phases 2 and 3 - data collection and model calibration.

    Science.gov (United States)

    2017-05-01

    This five-year project was initiated to collect materials and pavement performance data on a minimum of 100 : highway test sections around the state of Texas, incorporating both flexible pavements and overlays. Besides : being used to calibrate and v...

  6. Enhancement of electron-phonon coupling in Cs-overlayered intercalated bilayer graphene.

    Science.gov (United States)

    Kleeman, J; Sugawara, K; Sato, T; Takahashi, T

    2016-05-25

    We have performed high-resolution angle-resolved photoemission spectroscopy (ARPES) on cesium (Cs) intercalated bilayer graphene with a Cs overlayer (Cs-C8CsC8). Low-energy electron diffraction shows a (2  ×  2) pattern consistent with intercalation of a Cs layer similar to bulk C8Cs, in addition to the signature of a nearly commensurate superstructure created by the Cs overlayer. ARPES results reveal folding of the π bands due to the periodic (2  ×  2) potential of the intercalated Cs atoms, together with a free-electron-like state at the [Formula: see text] point. Significant mass renormalization is observed in the band dispersion near the Fermi level, indicative of strong electron-phonon coupling. Based on analysis of the self-energy, we find anisotropic electron-phonon coupling with an estimated strength of [Formula: see text]  ±  0.02 in the K-[Formula: see text] direction, and [Formula: see text] in the K-M direction. This coupling is much larger than that of other doped graphenes, and comparable to superconducting bulk GICs. We attribute this large electron-phonon coupling constant to the presence of the Cs overlayer, which highly dopes [Formula: see text] bands, and creates a structure similar to stage-I graphite intercalation compounds.

  7. Restoration of the Occlusal Vertical Dimension with an Overlay Removable Partial Denture: A Clinical Report.

    Science.gov (United States)

    Zanardi, Piero Rocha; Santos, Mayara Silva; Stegun, Roberto Chaib; Sesma, Newton; Costa, Bruno; Laganá, Dalva Cruz

    2016-10-01

    The process of tooth loss throughout life associated with severe occlusal wear may pose a challenge in the rehabilitation of partially edentulous arches. In these cases, many therapeutic procedures are necessary because each tooth must be restored to obtain the correct anatomical contour and recover the occlusal vertical dimension (OVD). A removable partial denture (RPD) with occlusal/incisal coverage, also known as an overlay RPD, is an alternative treatment option with fewer interventions, and, consequently, lower cost. This clinical report reviews the principles involved in the clinical indication for an overlay RPD, as well as the necessary planning and execution, to discuss the feasibility and clinical effectiveness of this treatment, identifying the indications, advantages, and disadvantages of this procedure through the presentation of a clinical case. The overlay RPD can be an alternative treatment for special situations involving partially edentulous arches in patients who need reestablishment of the OVD and/or realignment of the occlusal plane, and it can be used as a temporary or definitive treatment. The main advantages of this type of treatment are its simplicity, reversibility, and relatively low cost; however, further studies are needed to ensure the efficacy of this treatment option. © 2015 by the American College of Prosthodontists.

  8. Use of the Soft-agar Overlay Technique to Screen for Bacterially Produced Inhibitory Compounds.

    Science.gov (United States)

    Hockett, Kevin L; Baltrus, David A

    2017-01-14

    The soft-agar overlay technique was originally developed over 70 years ago and has been widely used in several areas of microbiological research, including work with bacteriophages and bacteriocins, proteinaceous antibacterial agents. This approach is relatively inexpensive, with minimal resource requirements. This technique consists of spotting supernatant from a donor strain (potentially harboring a toxic compound(s)) onto a solidified soft agar overlay that is seeded with a bacterial test strain (potentially sensitive to the toxic compound(s)). We utilized this technique to screen a library of Pseudomonas syringae strains for intraspecific killing. By combining this approach with a precipitation step and targeted gene deletions, multiple toxic compounds produced by the same strain can be differentiated. The two antagonistic agents commonly recovered using this technique are bacteriophages and bacteriocins. These two agents can be differentiated using two simple additional tests. Performing a serial dilution on a supernatant containing bacteriophage will result in individual plaques becoming less in number with greater dilution, whereas serial dilution of a supernatant containing bacteriocin will result a clearing zone that becomes uniformly more turbid with greater dilution. Additionally, a bacteriophage will produce a clearing zone when spotted onto a fresh soft agar overlay seeded with the same strain, whereas a bacteriocin will not produce a clearing zone when transferred to a fresh soft agar lawn, owing to the dilution of the bacteriocin.

  9. Energy Efficiency in MIMO Underlay and Overlay Device-to-Device Communications and Cognitive Radio Systems

    Science.gov (United States)

    Zappone, Alessio; Matthiesen, Bho; Jorswieck, Eduard Axel

    2017-02-01

    This paper addresses the problem of resource allocation for systems in which a primary and a secondary link share the available spectrum by an underlay or overlay approach. After observing that such a scenario models both cognitive radio and D2D communications, we formulate the problem as the maximization of the secondary energy efficiency subject to a minimum rate requirement for the primary user. This leads to challenging non-convex, fractional problems. In the underlay scenario, we obtain the global solution by means of a suitable reformulation. In the overlay scenario, two algorithms are proposed. The first one yields a resource allocation fulfilling the first-order optimality conditions of the resource allocation problem, by solving a sequence of easier fractional problems. The second one enjoys a weaker optimality claim, but an even lower computational complexity. Numerical results demonstrate the merits of the proposed algorithms both in terms of energy-efficient performance and complexity, also showing that the two proposed algorithms for the overlay scenario perform very similarly, despite the different complexity.

  10. Iron aluminide weld overlay coatings for boiler tube protection in coal-fired low NOx boilers

    Energy Technology Data Exchange (ETDEWEB)

    Banovic, S.W.; DuPont, J.N.; Marder, A.R. [Lehigh Univ., Bethlehem, PA (United States). Energy Research Center

    1997-12-01

    Iron aluminide weld overlay coatings are currently being considered for enhanced sulfidation resistance in coal-fired low NO{sub x} boilers. The use of these materials is currently limited due to hydrogen cracking susceptibility, which generally increases with an increase in aluminum concentration of the deposit. The overall objective of this program is to attain an optimum aluminum content with good weldability and improved sulfidation resistance with respect to conventional materials presently in use. Research has been initiated using Gas Tungsten Arc Welding (GTAW) in order to achieve this end. Under different sets of GTAW parameters (wire feed speed, current), both single and multiple pass overlays were produced. Characterization of all weldments was conducted using light optical microscopy, scanning electron microscopy, and electron probe microanalysis. Resultant deposits exhibited a wide range of aluminum contents (5--43 wt%). It was found that the GTAW overlays with aluminum contents above {approximately}10 wt% resulted in cracked coatings. Preliminary corrosion experiments of 5 to 10 wt% Al cast alloys in relatively simple H{sub 2}/H{sub 2}S gas mixtures exhibited corrosion rates lower than 304 stainless steel.

  11. NATO Education and Training Network

    Science.gov (United States)

    2012-02-01

    F-22 1.9.2.10 NETN Service Manager ..................................................................................................... F...Version Description Pitch Actors MSG-068 CGF Pitch Booster 1.2 Private Simulation Network Overlay Pitch NETN Service Manager MSG-068 Test tool for NETN...IEEE 1516-2010 1 Pitch NETN Service Manager Service Manager NETN Service Manager IEEE 1516-2010 1 Pitch Recorder Pitch Recorder Recorder IEEE 1516

  12. Intra-field on-product overlay improvement by application of RegC and TWINSCAN corrections

    Science.gov (United States)

    Sharoni, Ofir; Dmitriev, Vladimir; Graitzer, Erez; Perets, Yuval; Gorhad, Kujan; van Haren, Richard; Cekli, Hakki E.; Mulkens, Jan

    2015-03-01

    The on product overlay specification and Advanced Process Control (APC) is getting extremely challenging particularly after the introduction of multi-patterning applications like Spacer Assisted Double Patterning (SADP) and multipatterning techniques like N-repetitive Litho-Etch steps (LEN, N >= 2). When the latter is considered, most of the intrafield overlay contributors drop out of the overlay budget. This is a direct consequence of the fact that the scanner settings (like dose, illumination settings, etc.) as well as the subsequent processing steps can be made very similar for two consecutive Litho-Etch layers. The major overlay contributor that may require additional attention is the Image Placement Error (IPE). When the inter-layer overlay is considered, controlling the intra-field overlay contribution gets more complicated. In addition to the IPE contribution, the TWINSCANTM lens fingerprint in combination with the exposure settings is going to play a role as well. Generally speaking, two subsequent functional layers have different exposure settings. This results in a (non-reticle) additional overlay contribution. In this paper, we have studied the wafer overlay correction capability by RegC® in addition to the TWINSCANTM intrafield corrections to improve the on product overlay performance. RegC® is a reticle intra-volume laser writing technique that causes a predictable deformation element (RegC® deformation element) inside the quartz (Qz) material of a reticle. This technique enables to post-process an existing reticle to correct for instance for IPE. Alternatively, a pre-determined intra-field fingerprint can be added to the reticle such that it results in a straight field after exposure. This second application might be very powerful to correct for instance for (cold) lens fingerprints that cannot be corrected by the scanner itself. Another possible application is the intra-field processing fingerprint. One should realize that a RegC® treatment of a

  13. Three-dimensional magnetic resonance imaging overlay to assist with percutaneous transhepatic access at the time of cardiac catheterization

    Directory of Open Access Journals (Sweden)

    Wendy Whiteside

    2015-01-01

    Full Text Available Multimodality image overlay is increasingly used for complex interventional procedures in the cardiac catheterization lab. We report a case in which three-dimensional magnetic resonance imaging (3D MRI overlay onto live fluoroscopic imaging was utilized to safely obtain transhepatic access in a 12-year-old patient with prune belly syndrome, complex and distorted abdominal anatomy, and a vascular mass within the liver.

  14. Marginal quality and fracture strength of root-canal treated mandibular molars with overlay restorations after thermocycling and mechanical loading.

    Science.gov (United States)

    Dere, Mustafa; Ozcan, Mutlu; Göhring, Till N

    2010-08-01

    To evaluate marginal quality, fracture modes, and loads-to-failure of different overlay restorations in rootcanal treated molars in a laboratory setup. Thirty-two mandibular first molars were randomly assigned to four groups (n = 8): UTR= untreated (control), RCT-COM= root canal treated (RCT)+ lab-made composite overlay, RCT-FRC= RCT+composite resin overlay with two layers of multidirectional woven glass fibers; RCT-CER: RCT+ceramic overlay. The teeth in all groups were subjected to thermocycling and mechanical loading (TCML) in a computer-controlled masticator (1,200,000 loads, 49 N, 1.7 Hz, 3000 temperature cycles of 5°C to 50°C). Marginal adaptation was evaluated before and after TCML with scanning electron microscopy at 200X at the tooth-to-luting composite (IF1) and luting composite-to restoration (IF2) interfaces. After TCML, all specimens were loaded to failure in a universal testing machine at 0.5 mm/min. Data were analyzed with ANOVA and Bonferroni correction. Marginal adaptation decreased from 93 ± 3.4 to 82 ± 6.5 % at IF1 after TCML (p > 0.001) but the decrease was not significant between the groups (p = 0.8130). At IF2, ceramic overlays showed about 10% lower marginal adaptation than composite overlays (p composite delamination from the glass-fiber weaver layer. As cusp-covering overlay restorations in root canal treated molars, composite resin overlays with and without fiber reinforcement performed similar to intact teeth with varying failure types. While intact teeth failed exclusively in reparable modes, all other restorations failed in a catastrophic manner, except half of the fiber reinforced composite group.

  15. Considerations for Software Defined Networking (SDN): Approaches and use cases

    Science.gov (United States)

    Bakshi, K.

    Software Defined Networking (SDN) is an evolutionary approach to network design and functionality based on the ability to programmatically modify the behavior of network devices. SDN uses user-customizable and configurable software that's independent of hardware to enable networked systems to expand data flow control. SDN is in large part about understanding and managing a network as a unified abstraction. It will make networks more flexible, dynamic, and cost-efficient, while greatly simplifying operational complexity. And this advanced solution provides several benefits including network and service customizability, configurability, improved operations, and increased performance. There are several approaches to SDN and its practical implementation. Among them, two have risen to prominence with differences in pedigree and implementation. This paper's main focus will be to define, review, and evaluate salient approaches and use cases of the OpenFlow and Virtual Network Overlay approaches to SDN. OpenFlow is a communication protocol that gives access to the forwarding plane of a network's switches and routers. The Virtual Network Overlay relies on a completely virtualized network infrastructure and services to abstract the underlying physical network, which allows the overlay to be mobile to other physical networks. This is an important requirement for cloud computing, where applications and associated network services are migrated to cloud service providers and remote data centers on the fly as resource demands dictate. The paper will discuss how and where SDN can be applied and implemented, including research and academia, virtual multitenant data center, and cloud computing applications. Specific attention will be given to the cloud computing use case, where automated provisioning and programmable overlay for scalable multi-tenancy is leveraged via the SDN approach.

  16. Pattern recognition and data mining techniques to identify factors in wafer processing and control determining overlay error

    Science.gov (United States)

    Lam, Auguste; Ypma, Alexander; Gatefait, Maxime; Deckers, David; Koopman, Arne; van Haren, Richard; Beltman, Jan

    2015-03-01

    On-product overlay can be improved through the use of context data from the fab and the scanner. Continuous improvements in lithography and processing performance over the past years have resulted in consequent overlay performance improvement for critical layers. Identification of the remaining factors causing systematic disturbances and inefficiencies will further reduce overlay. By building a context database, mappings between context, fingerprints and alignment & overlay metrology can be learned through techniques from pattern recognition and data mining. We relate structure (`patterns') in the metrology data to relevant contextual factors. Once understood, these factors could be moved to the known effects (e.g. the presence of systematic fingerprints from reticle writing error or lens and reticle heating). Hence, we build up a knowledge base of known effects based on data. Outcomes from such an integral (`holistic') approach to lithography data analysis may be exploited in a model-based predictive overlay controller that combines feedback and feedforward control [1]. Hence, the available measurements from scanner, fab and metrology equipment are combined to reveal opportunities for further overlay improvement which would otherwise go unnoticed.

  17. Visually assessed colour overlay features in shear-wave elastography for breast masses: quantification and diagnostic performance.

    Science.gov (United States)

    Gweon, Hye Mi; Youk, Ji Hyun; Son, Eun Ju; Kim, Jeong-Ah

    2013-03-01

    To determine whether colour overlay features can be quantified by the standard deviation (SD) of the elasticity measured in shear-wave elastography (SWE) and to evaluate the diagnostic performance for breast masses. One hundred thirty-three breast lesions in 119 consecutive women who underwent SWE before US-guided core needle biopsy or surgical excision were analysed. SWE colour overlay features were assessed using two different colour overlay pattern classifications. Quantitative SD of the elasticity value was measured with the region of interest including the whole breast lesion. For the four-colour overlay pattern, the area under the ROC curve (Az) was 0.947; with a cutoff point between pattern 2 and 3, sensitivity and specificity were 94.4 % and 81.4 %. According to the homogeneity of the elasticity, the Az was 0.887; with a cutoff point between reasonably homogeneous and heterogeneous, sensitivity and specificity were 86.1 % and 82.5 %. For the SD of the elasticity, the Az was 0.944; with a cutoff point of 12.1, sensitivity and specificity were 88.9 % and 89.7 %. The colour overlay features showed significant correlations with the quantitative SD of the elasticity (P colour overlay features and the SD of the elasticity in SWE showed excellent diagnostic performance and showed good correlations between them.

  18. Overlay of conventional angiographic and en-face OCT images enhances their interpretation

    Directory of Open Access Journals (Sweden)

    Pool Chris W

    2005-06-01

    Full Text Available Abstract Background Combining characteristic morphological and functional information in one image increases pathophysiologic understanding as well as diagnostic accuracy in most clinical settings. En-face optical coherence tomography (OCT provides a high resolution, transversal OCT image of the macular area combined with a confocal image of the same area (OCT C-scans. Creating an overlay image of a conventional angiographic image onto an OCT image, using the confocal part to facilitate transformation, combines structural and functional information of the retinal area of interest. This paper describes the construction of such overlay images and their aid in improving the interpretation of OCT C-scans. Methods In various patients, en-face OCT C-scans (made with a prototype OCT-Ophthalmoscope (OTI, Canada in use at the Department of Ophthalmology (Academic Medical Centre, Amsterdam, The Netherlands and conventional fluorescein angiography (FA were performed. ImagePro, with a custom made plug-in, was used to make an overlay-image. The confocal part of the OCT C-scan was used to spatially transform the FA image onto the OCT C-scan, using the vascular arcades as a reference. To facilitate visualization the transformed angiographic image and the OCT C-scan were combined in an RGB image. Results The confocal part of the OCT C-scan could easily be fused with angiographic images. Overlay showed a direct correspondence between retinal thickening and FA leakage in Birdshot retinochoroiditis, localized the subretinal neovascular membrane and correlated anatomic and vascular leakage features in myopia, and showed the extent of retinal and pigment epithelial detachment in retinal angiomatous proliferation as FA leakage was subject to blocked fluorescence. The overlay mode provided additional insight not readily available in either mode alone. Conclusion Combining conventional angiographic images and en-face OCT C-scans assists in the interpretation of both

  19. Framework for near-field-communication-based geo-localization and personalization for Android-based smartphones--application in hospital environments.

    Science.gov (United States)

    Meng, Philipp; Fehre, Karsten; Rappelsberger, Andrea; Adlassnig, Klaus-Peter

    2014-01-01

    Various applications using near field communication (NFC) have been developed for the medical sector. As a method of short-range wireless contact-driven data transfer, NFC is a useful tool in medicine. It can be used to transfer data such as blood pressure, control adherence to medication, or transmit in vivo data. The first proposed general framework uses NFC as a mechanism for indoor geo-localization in hospitals. NFC geo-localization is economical compared to classical concepts using indoor GPS or WLAN triangulation, and the granularity of location retrieval can be defined at a tag level. Using this framework, we facilitate the development of medical applications that require exact indoor geo-localization. Multi-user Android systems are addressed in the second framework. Using private NFC tags, users are able to carry on their personal settings for enabled applications. This eliminates the need for multiple user accounts on common Android devices, improves usability, and eases technical administration. Based on the prototypes presented here, we show a novel concept of using NFC-enabled Android devices in hospital environments.

  20. Corrosion resistance and microstructure of alloy 625 weld overlay on ASTM A516 grade 70

    Energy Technology Data Exchange (ETDEWEB)

    Moradi, Mohammad J. [Amirkabir Univ. of Technology, Tehran (Iran, Islamic Republic of). Petroleum Engineering Dept.; Ketabchi, Mostafa [Amirkabir Univ. of Technology, Tehran (Iran, Islamic Republic of). Mining and Metallurgical Engineering Dept.

    2016-02-01

    Nickel-based alloys are a crucial class of materials because of their excellent corrosion resistance. In the present study, single layer and two layers alloy 625 weld overlays were deposited by GTAW process on A516 grade 70 carbon steel. The dilution in terms of Fe, Ni, Mo and Nb content was calculated in 30 points of weld overlay. Microstructure observations showed that alloy 625 had austenitic structure with two types of Laves and NbC secondary phases. The uniform and pitting corrosion resistance of alloy 625 weld overlay as casted and as forged were evaluated in accordance with ASTM G48-2011 standard at different temperatures to determine the weight loss and critical pitting temperature. For achieving a better comparison, samples from alloy 625 as casted and as forged were tested under the same conditions. The results point out that single layer alloy 625 weld overlay is not suitable for chloride containing environments, two layers alloy 625 weld overlay and alloy 625 as casted have acceptable corrosion resistance and almost the same critical pitting temperature. Alloy 625 as forged has the best corrosion resistance and the highest critical pitting temperature among all test specimens. Also, the corrosion behavior was evaluated in accordance with ASTM G28 standard. The corrosion rate of single layer weld overlay was unacceptable. The average corrosion rate of two layers weld overlay and in casted condition were 35.82 and 33.01 mpy, respectively. [German] Nickellegierungen sind aufgrund ihres exzellenten Korrosionswiderstandes eine bedeutende Werkstoffklasse. In der diesem Beitrag zugrunde liegenden Studie wurden mittels WIG-Schweissens ein- und zweilagige Schweissplattierungen auf den Kohlenstoffstahl A516 (Grade 70) aufgebracht. Die Vermischung in Form des Fe-, Ni-, Mo- und Nb-Gehaltes wurde an 30 Punkten der Schweissplattierungen berechnet. Die mikrostrukturellen Untersuchungen ergaben, dass die Legierung 625 eine austenitische Struktur mit zwei Arten von

  1. Learning GIS and exploring geolocated data with the all-in-one Geolokit toolbox for Google Earth

    Science.gov (United States)

    Watlet, A.; Triantafyllou, A.; Bastin, C.

    2016-12-01

    GIS software are today's essential tools to gather and visualize geological data, to apply spatial and temporal analysis and finally, to create and share interactive maps for further investigations in geosciences. Such skills are especially essential to learn for students who go through fieldtrips, samples collections or field experiments. However, time is generally missing to teach in detail all the aspects of visualizing geolocated geoscientific data. For these purposes, we developed Geolokit: a lightweight freeware dedicated to geodata visualization and written in Python, a high-level, cross-platform programming language. Geolokit software is accessible through a graphical user interface, designed to run in parallel with Google Earth, benefitting from the numerous interactive capabilities. It is designed as a very user-friendly toolbox that allows `geo-users' to import their raw data (e.g. GPS, sample locations, structural data, field pictures, maps), to use fast data analysis tools and to visualize these into the Google Earth environment using KML code; with no require of third party software, except Google Earth itself. Geolokit comes with a large number of geosciences labels, symbols, colours and placemarks and is applicable to display several types of geolocated data, including: Multi-points datasets Automatically computed contours of multi-points datasets via several interpolation methods Discrete planar and linear structural geology data in 2D or 3D supporting large range of structures input format Clustered stereonets and rose diagrams 2D cross-sections as vertical sections Georeferenced maps and grids with user defined coordinates Field pictures using either geo-tracking metadata from a camera built-in GPS module, or the same-day track of an external GPS In the end, Geolokit is helpful for quickly visualizing and exploring data without losing too much time in the numerous capabilities of GIS software suites. We are looking for students and teachers to

  2. Characterizing SMS spam in a large cellular network via mining victim spam reports

    OpenAIRE

    Skudlark, Ann

    2015-01-01

    In this paper a study of SMS messages in a large US based cellular carrier utilizing both customer reported SMS spam and network Call Detail Records (CDRs) is conducted to develop a comprehensive understanding of SMS spam in order to develop strategies and approaches to detect and control SMS spam activity. The analysis provides insights into content classification of spam campaigns as well as spam characteristics based on sending patterns, tenure and geolocation.

  3. Resource and power management in next generation networks

    OpenAIRE

    Limani Fazliu, Zana

    2017-01-01

    The limits of today's cellular communication systems are constantly being tested by the exponential increase in mobile data traffic, a trend which is poised to continue well into the next decade. Densification of cellular networks, by overlaying smaller cells, i.e., micro, pico and femtocells, over the traditional macrocell, is seen as an inevitable step in enabling future networks to support the expected increases in data rate demand. Next generation networks will most certainly be more hete...

  4. A Production Proven Technique For Machine-To-Machine Overlay Matching

    Science.gov (United States)

    Cummings, Michael J.; Haley, Norman J.; Ngo, Ken T.; Schaller, John W.

    1989-07-01

    The natural progression of today's semiconductor industry is toward smaller geometric features and registration requirements. Typically, this progression results in high capital equipment investments, along with a large capacity reduction per investment dollar for most lithographic exposure processes. One major cause for the capacity loss is the industry's willingness to migrate from full-field scanning projection printers to a lower throughput field-by-field alignment step-and-repeat exposure system. Standard Microsystems Corporation (SMC) sought to achieve higher performance on its scanners without compromising throughput. The original goal at SMC was to improve Perkin-Elmer's Micralign 641 HT machine-to-machine registration specification of ± 0.30 micron to less than ± 0.25 micron. With this in mind, we set out to investigate the true alignment and registration limitations of a Micralign Model 600 HT Series Projection Aligner. Although SMC was apparently successful at matching two Micralign 641 HT systems to ± 0.25 micron by manually reading verniers, this technique proved to be time consuming and prone to human error. Electrical probing of wafers was considered, but the special masks and processing steps and its destructive nature were considered undesirable. For this study, an automatic optical overlay measurement system was used to optimize overlay on the SMC Micralign systems. The results were enlightening. The specified overlay of ± 0.30 micron for 98% of the data improved to better than ± 0.25 micron, 3 sigma. These results were achieved without the use of Automatic Magnification Compensation (AVM/AMC). We also discovered that many otherwise transparent mechanical/optical anomalies, such as contamination and scan interference, could be readily identified. Experimental data is presented and the beneficial application of this technique to a production process is discussed.

  5. Association of Lateral Crural Overlay Technique With Strength of the Lower Lateral Cartilages.

    Science.gov (United States)

    Insalaco, Louis; Rashes, Emma R; Rubin, Samuel J; Spiegel, Jeffrey H

    2017-12-01

    The lateral crural overlay technique is a powerful technique for altering nasal tip projection and rotation. By overlapping and thus shortening the lateral crura, the nasal tip is shortened and rotated upward, thus decreasing projection and increasing rotation. There is no data to show the association of this technique with the strength of the lower lateral cartilage. Strengthening of the lower lateral cartilages would presumably lead to resistance to external nasal valve collapse and improved airway. In this cadaver study, we set out to determine the differences in the strength and resilience of the lateral crura after performing lateral crural overlay using 2 different techniques. Seven individual lower lateral cartilages were harvested from 6 cadavers for analysis. Each of the 7 cartilages was included sequentially in 3 test groups in the following order: a preprocedure group (preP), a postprocedure group (postP) in which the lateral crural overlay technique was performed, and a postprocedure with glue group (postPG) in which cyanoacrylate glue was added to the postP cartilages to simulate cartilage healing. A force gauge was used to measure the force required to deflect the lower lateral cartilages distances from 1 to 6 mm. Differences measured in newtons (N) for strength and resilience of lateral crura between the preP, postP, and postPG groups. A statistically significant increase in lower lateral cartilage resilience was noted between the preP and postPG groups at all distances of tip deflection (1 mm, 0.20 vs 0.70 N; P strength and resilience to the lateral crura of the lower lateral cartilages, which should in turn decrease the likelihood of external nasal valve collapse postoperatively. NA.

  6. Passivating surface states on water splitting hematite photoanodes with alumina overlayers

    KAUST Repository

    Le Formal, Florian

    2011-01-24

    Hematite is a promising material for inexpensive solar energy conversion via water splitting but has been limited by the large overpotential (0.5-0.6 V) that must be applied to afford high water oxidation photocurrent. This has conventionally been addressed by coating it with a catalyst to increase the kinetics of the oxygen evolution reaction. However, surface recombination at trapping states is also thought to be an important factor for the overpotential, and herein we investigate a strategy to passivate trapping states using conformal overlayers applied by atomic layer deposition. While TiO2 overlayers show no beneficial effect, we find that an ultra-thin coating of Al2O3 reduces the overpotential required with state-of-the-art nano-structured photo-anodes by as much as 100 mV and increases the photocurrent by a factor of 3.5 (from 0.24 mA cm-2 to 0.85 mA cm-2) at +1.0 V vs. the reversible hydrogen electrode (RHE) under standard illumination conditions. The subsequent addition of Co2+ ions as a catalyst further decreases the overpotential and leads to a record photocurrent density at 0.9 V vs. RHE (0.42 mA cm-2). A detailed investigation into the effect of the Al2O3 overlayer by electrochemical impedance and photoluminescence spectroscopy reveals a significant change in the surface capacitance and radiative recombination, respectively, which distinguishes the observed overpotential reduction from a catalytic effect and confirms the passivation of surface states. Importantly, this work clearly demonstrates that two distinct loss processes are occurring on the surface of high-performance hematite and suggests a viable route to individually address them. © The Royal Society of Chemistry 2011.

  7. Formate stability and carbonate hydrogenation on strained Cu overlayers on Pt(111)

    DEFF Research Database (Denmark)

    Schumacher, Nana Maria Pii; Andersson, Klas Jerker; Nerlov, Jesper

    2008-01-01

    Formate (HCOO) synthesis, decomposition and the hydrogenation of carbonate (CO3) on Cu overlayers deposited on a Pt(111) single crystal are investigated to examine the reactivity of a Cu surface under tensile strain with defects present. Formate is synthesized from a 0.5 bar mixture of 70% CO2 an...... of formate on the surface, or any other hydrogenation product, could not be established during or after H2 exposure by PM-IRRAS, EELS or TPD. Even so, the results suggest that carbonate and its hydrogenation may constitute a relevant pathway to methanol production....

  8. Stabilizing hybrid perovskites against moisture and temperature via non-hydrolytic atomic layer deposited overlayers

    Energy Technology Data Exchange (ETDEWEB)

    Kim, In Soo; Martinson, Alex B. F.

    2015-01-01

    A novel non-hydrolytic (nh) surface chemistry is utilized to allow the direct synthesis of pinhole-fee oxide overlayers directly on conventional hybrid perovskite halide absorbers without damage. Utilizing water-free ALD Al2O3 passivation, a minimum of ten-fold increase in stability against relative humidity (RH) 85% was achieved along with a dramatically improved thermal resistance (up to 250 °C). Moreover, we extend this approach to synthesize nh-TiO2 directly on hybrid perovskites to establish its potential in inverted photovoltaic devices as a dual stabilizing and electron accepting layer, as evidenced by photoluminescence (PL) quenching.

  9. A comparative study of three commonly used two-dimensional overlay generation methods in bite mark analysis

    Science.gov (United States)

    Pajnigara, Nilufer Gev; Balpande, Apeksha S; Motwani, Mukta B; Choudhary, Anuraag; Thakur, Samantha; Pajnigara, Natasha G

    2017-01-01

    Aim: The present study attempts to compare the bite mark overlays generated by three different methods. The objectives of the study were to compare the three commonly used techniques for overlay generation and to evaluate the interobserver reliability in assessing bite marks by these methods. Materials and Methods: Overlays were produced from the biting surfaces of six upper and six lower anterior teeth of 30 dental study models using the following three methods: (a) Hand tracing from wax impressions, (b) radiopaque impression method and (c) computer-based method. Results: The computer-based method was found to be the most accurate method. Of the two hand tracing methods, radiopaque wax impression method was better than the wax impression method for overlay generation. Conclusions: It is recommended that forensic odontologists use computerized method, but the use of hand tracing overlays in bite mark comparison cases using radiopaque wax impression method can also be done where sophisticated software and trained persons in forensic odontology are not available. PMID:29391724

  10. Use of Hydrogen Chemisorption and Ethylene Hydrogenation as Predictors for Aqueous Phase Reforming of Lactose over Ni@Pt and Co@Pt Bimetallic Overlayer Catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Lai, Qinghua; Skoglund, Michael D.; Zhang, Chen; Morris, Allen R.; Holles, Joseph H.

    2016-10-20

    Overlayer Pt on Ni (Ni@Pt) or Co (Co@Pt) were synthesized and tested for H2 generation from APR of lactose. H2 chemisorption descriptor showed that Ni@Pt and Co@Pt overlayer catalysts had reduced H2 adsorption strength compared to a Pt only catalyst, which agree with computational predictions. The overlayer catalysts also demonstrated lower activity for ethylene hydrogenation than the Pt only catalyst, which likely resulted from decreased H2 binding strength decreasing the surface coverage of H2. XAS results showed that overlayer catalysts exhibited higher white line intensity than the Pt catalyst, which indicates a negative d-band shift for the Pt overlayer, further providing evidence for overlayer formation. Lactose APR studies showed that lactose can be used as feedstock to produce H2 and CO under desirable reaction conditions. The Pt active sites of Ni@Pt and Co@Pt overlayer catalysts showed significantly enhanced H2 production selectivity and activity when compared with that of a Pt only catalyst. The single deposition overlayer with the largest d-band shift showed the highest H2 activity. The results suggest that overlayer formation using directed deposition technique could modify the behavior of the surface metal and ultimately modify the APR activity.

  11. Mapping the geography of science: distribution patterns and networks of relations among cities and institutes

    NARCIS (Netherlands)

    Leydesdorff, L.; Persson, O.

    2010-01-01

    Using Google Earth, Google Maps, and/or network visualization programs such as Pajek, one can overlay the network of relations among addresses in scientific publications onto the geographic map. The authors discuss the pros and cons of various options, and provide software (freeware) for bridging

  12. Broker Placement in Latency-aware Peer-to-Peer Networks

    NARCIS (Netherlands)

    Garbacki, P.; Epema, D.; van Steen, M.R.

    2008-01-01

    In large peer-to-peer (P2P) overlay networks, nodes usually share resources to support all kinds of applications. In such networks, a subset of the nodes may assume the role of broker in order to act as intermediaries for finding the shared resources. When some notion of distance between nodes such

  13. Internet factories: Creating application-specific networks on-demand

    NARCIS (Netherlands)

    Strijkers, R.J.; Makkes, M.X.; Laat, C. de; Meijer, R.J.

    2014-01-01

    We introduce the concept of Internet factories. Internet factories structure the task of creating and managing application-specific overlay networks using infrastructure-as-a-service clouds. We describe the Internet factory architecture and report on a proof of concept with three examples that

  14. Cluster-based service discovery for heterogeneous wireless sensor networks

    NARCIS (Netherlands)

    Marin Perianu, Raluca; Scholten, Johan; Havinga, Paul J.M.; Hartel, Pieter H.

    We propose an energy-efficient service discovery protocol for heterogeneous wireless sensor networks that interact with the users in open and dynamic environments. Our solution exploits a cluster overlay, where the clusterhead nodes form a distributed service registry. A service lookup results in

  15. Cluster-based service discovery for heterogeneous wireless sensor networks

    NARCIS (Netherlands)

    Marin Perianu, Raluca; Scholten, Johan; Havinga, Paul J.M.; Hartel, Pieter H.

    2007-01-01

    We propose an energy-efficient service discovery protocol for heterogeneous wireless sensor networks. Our solution exploits a cluster overlay, where the clusterhead nodes form a distributed service registry. A service lookup results in visiting only the clusterhead nodes. We aim for minimizing the

  16. Spatial Analysis for Potential Water Catchment Areas using GIS: Weighted Overlay Technique

    Science.gov (United States)

    Awanda, Disyacitta; Anugrah Nurul, H.; Musfiroh, Zahrotul; Dinda Dwi, N. P.

    2017-12-01

    The development of applied GIS is growing rapidly and has been widely applied in various fields. Preparation of a model to obtain information is one of the benefits of GIS. Obtaining information for water resources such as water catchment areas is one part of GIS modelling. Water catchment model can be utilized to see the distribution of potential and ability of a region in water absorbing. The use of overlay techniques with the weighting obtained from the literature from previous research is used to build the model. Model builder parameters are obtained through remote sensing interpretation techniques such as land use, landforms, and soil texture. Secondary data such as rock type maps are also used as water catchment model parameters. The location of this research is in the upstream part of the Opak river basin. The purpose of this research is to get information about potential distribution of water catchment area with overlay technique. The results of this study indicate the potential of water catchment areas with excellent category, good, medium, poor and very poor. These results may indicate that the Upper river basin is either good or in bad condition, so it can be used for better water resources management policy determination.

  17. A high-accuracy surgical augmented reality system using enhanced integral videography image overlay.

    Science.gov (United States)

    Zhang, Xinran; Chen, Guowen; Liao, Hongen

    2015-01-01

    Image guided surgery has been used in clinic to improve the surgery safety and accuracy. Augmented reality (AR) technique, which can provide intuitive image guidance, has been greatly evolved these years. As one promising approach of surgical AR systems, integral videography (IV) autostereoscopic image overlay has achieved accurate fusion of full parallax guidance into surgical scene. This paper describes an image enhanced high-accuracy IV overlay system. A flexible optical image enhancement system (IES) is designed to increase the resolution and quality of IV image. Furthermore, we introduce a novel IV rendering algorithm to promote the spatial accuracy with the consideration of distortion introduced by micro lens array. Preliminary experiments validated that the image accuracy and resolution are improved with the proposed methods. The resolution of the IV image could be promoted to 1 mm for a micro lens array with pitch of 2.32 mm and IES magnification value of 0.5. The relative deviation of accuracy in depth and lateral directions are -4.68 ± 0.83% and -9.01 ± 0.42%.

  18. Electron coincidence studies of sulfur-overlayers on Cu(001) and Ni(001) surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Di Filippo, G., E-mail: gianluca.filippo@fau.de [Max-Planck Institut für Mikrostrukturphysik, Weinberg 2, 06120 Halle (Germany); Schumann, F.O.; Patil, S.; Wei, Z. [Max-Planck Institut für Mikrostrukturphysik, Weinberg 2, 06120 Halle (Germany); Stefani, G. [CNISM and Dipartimento di Scienze, Università Roma Tre, Via della Vasca Navale 84, 00146 Rome (Italy); Fratesi, G. [Dipartimento di Fisica, Università degli Studi di Milano, Via Celoria 16, 20133 Milan (Italy); Trioni, M.I. [CNR – National Research Council of Italy, ISTM, Via Golgi 19, 20133 Milan (Italy); Kirschner, J. [Max-Planck Institut für Mikrostrukturphysik, Weinberg 2, 06120 Halle (Germany)

    2016-08-15

    Highlights: • The LVV Auger decay of different sulfur-overlayers is investigated. • The decay can be described within a two-step model. • The Auger line shapes furnish information on the electronic structure at the surface. • The e–e correlation energy is hardly affected by coverage or substrate variations. - Abstract: We have prepared different sulfur-overlayers on Cu(001) and Ni(001) surfaces which differ in their coverage and local environment of the S adatoms. Via photon absorption we excited the S 2p level and studied the subsequent Auger decay with a coincidence spectrometer. We discuss the variation of the coincidence rate as a function of the energy sum of the photo-Auger electron pair. This is linked to the binding energy of the double-hole state. We find that the photon energy has no dramatic influence on the spectra. Differences are observed when the local environment of sulfur is changed. The observed spectral changes are mainly ascribable to the variation of the density of states at the different surfaces. On the contrary, the strength of electron–electron correlation at the surface states is hardly affected by coverage or substrate variation.

  19. Bandwidth and power allocation for two-way relaying in overlay cognitive radio systems

    KAUST Repository

    Alsharoa, Ahmad M.

    2014-12-01

    In this paper, the problem of both bandwidth and power allocation for two-way multiple relay systems in overlay cognitive radio (CR) setup is investigated. In the CR overlay mode, primary users (PUs) cooperate with cognitive users (CUs) for mutual benefits. In our framework, we propose that the CUs are allowed to allocate a part of the PUs spectrum to perform their cognitive transmission. In return, acting as an amplify-and-forward two-way relays, they are used to support PUs to achieve their target data rates over the remaining bandwidth. More specifically, CUs acts as relays for the PUs and gain some spectrum as long as they respect a specific power budget and primary quality-of-service constraints. In this context, we first derive closed-form expressions for optimal transmit power allocated to PUs and CUs in order to maximize the cognitive objective. Then, we employ a strong optimization tool based on particle swarm optimization algorithm to find the optimal relay amplification gains and optimal cognitive released bandwidths as well. Our numerical results illustrate the performance of our proposed algorithm for different utility metrics and analyze the impact of some system parameters on the achieved performance.

  20. Composite optical fiber polarizer with ternary copolymer overlay for large range modulation of phase difference

    Science.gov (United States)

    Cui, Minxin; Tian, Xiujie; Zou, Gang; Zhu, Bing; Zhang, Qijin

    2017-04-01

    In this work, a ternary copolymer composed of (E)-2-(4-((4-isocyanophenyl) diazenyl) phenoxy) ethyl methacrylate (2-CN), methacrylisobutyl polyhedral oligomeric silsesquioxane (MAPOSS) and 2,2,2-trifluoroethyl methacrylate (TFEMA) is synthesized and used as the overlay for composite optical fiber, in which cage-like POSS component and fluorine-containing component are used to reduce refractive index, and azobenzene component is used to finely manipulate the refractive indices in two orthogonal directions through photo-induced orientation under irradiation of polarized light. Before irradiation, the refractive index of terpolymer (1.4503) is slightly higher than that of the core material (1.4489) of commercial silica single-mode fiber, which is obtained by optimizing the amount of each monomer. After the irradiation of 435 nm polarized light, refractive indices of the overlay in two orthogonal directions decrease, and two values have been finely manipulated so that one is higher and another is lower than the refractive index of the fiber core by optimizing irradiation time. In this way, a radial loss type fiber polarization modulator is obtained. By changing the polarization direction of the irradiation at 435 nm, the polarization of propagating light at 1550 nm in the fiber can also be modulated continuously. The maximum change of phase difference is about 300°, making the device useful as a quarter-wave plate or a half-wave plate.

  1. Hot Corrosion of Inconel 625 Overlay Weld Cladding in Smelting Off-Gas Environment

    Science.gov (United States)

    Mohammadi Zahrani, E.; Alfantazi, A. M.

    2013-10-01

    Degradation mechanisms and hot corrosion behavior of weld overlay alloy 625 were studied. Phase structure, morphology, thermal behavior, and chemical composition of deposited salt mixture on the weld overlay were characterized utilizing XRD, SEM/EDX, DTA, and ICP/OES, respectively. Dilution level of Fe in the weldment, dendritic structure, and degradation mechanisms of the weld were investigated. A molten phase formed on the weld layer at the operating temperature range of the boiler, which led to the hot corrosion attack in the water wall and the ultimate failure. Open circuit potential and weight-loss measurements and potentiodynamic polarization were carried out to study the hot corrosion behavior of the weld in the simulated molten salt medium at 873 K, 973 K, and 1073 K (600 °C, 700 °C, and 800 °C). Internal oxidation and sulfidation plus pitting corrosion were identified as the main hot corrosion mechanisms in the weld and boiler tubes. The presence of a significant amount of Fe made the dendritic structure of the weld susceptible to preferential corrosion. Preferentially corroded (Mo, Nb)-depleted dendrite cores acted as potential sites for crack initiation from the surface layer. The penetration of the molten phase into the cracks accelerated the cracks' propagation mainly through the dendrite cores and further crack branching/widening.

  2. Development of a novel accelerometer based on an overlay detection bridge

    Science.gov (United States)

    Chunhui, Du; Changde, He; Xiaoyang, Ge; Yongping, Zhang; Jiaqi, Yu; Xiaopeng, Song; Wendong, Zhang

    2013-02-01

    This paper describes the design, simulation, processing and test result of a high sensitivity accelerometer based on the piezoresistive effect which uses an overlay bridge detection method. The structure of this accelerometer is supersymmetric “mass-beams". This accelerometer has 8 beams, where two varistors are put in the two ends. Four varistors compose a Wheatstone bridge and the output voltages of the 4 Wheatstone bridges have been superimposed as the final output voltage. The sensitivity of the accelerometer can be improved effectively by these clever methods. A simplified mathematical model has been created to analyze the mechanical properties of the sensor, then the finite element modeling and simulation have been used to verify the feasibility of the accelerometer. The results show that the sensitivity of the accelerometer is 1.1381 mV/g, which is about four times larger than that of the single bridge accelerometers and series bridge sensor. The bandwidth is 0-1000 Hz which is equal to that of the single bridge accelerometers and the series bridge sensor. The comparison reveals that the new overlay detection bridge method can improve the sensitivity of the sensor in the same bandwidth. Meanwhile, this method provides an effective method to improve the sensitivity of piezoresistive sensors.

  3. Evaluating the mechanical performance of Very Thin Asphalt Overlay (VTAO as a sustainable rehabilitation strategy in urban pavements

    Directory of Open Access Journals (Sweden)

    M. Sol-Sánchez

    2017-07-01

    Full Text Available Very Thin Asphalt Overlay (VTAO has been introduced as an alternative to traditional thick overlays, seal coats, and micro-surfacings. Nonetheless, there are some challenges that still remain regarding the application of VTAOs (such as mixture type, cohesiveness, wear resistance, cracking and durability, particularly in heavy traffic urban areas. Therefore, this paper presents an extensive comparative evaluation of the mechanical performance, durability and safety issues (cohesiveness, adhesiveness, ageing, cracking, plastic deformation, permeability, macrotexture, skid and wear resistance, and fuel resistance of a VTAO (20 mm thick and a high performance BBTM 11B (35 mm thick, commonly used as an open-graded mixture for pavement overlays. The results demonstrated that VTAO is an appropriate material for urban pavements as it provides good durability and resistance to the propagation of defects. Nonetheless, further studies are required to improve its behavior under distresses related to plastic deformations and safety properties.

  4. Annual cycle and migration strategies of a trans-Saharan migratory songbird: a geolocator study in the great reed warbler.

    Directory of Open Access Journals (Sweden)

    Hilger W Lemke

    Full Text Available Recent technological advancements now allow us to obtain geographical position data for a wide range of animal movements. Here we used light-level geolocators to study the annual migration cycle in great reed warblers (Acrocephalus arundinaceus, a passerine bird breeding in Eurasia and wintering in sub-Saharan Africa. We were specifically interested in seasonal strategies in routes and schedules of migration. We found that the great reed warblers (all males, no females were included migrated from the Swedish breeding site in early August. After spending up to three weeks at scattered stopover sites in central to south-eastern Europe, they resumed migration and crossed the Mediterranean Sea and Sahara Desert without lengthy stopovers. They then spread out over a large overwintering area and each bird utilised two (or even three main wintering sites that were spatially separated by a distinct mid-winter movement. Spring migration initiation date differed widely between individuals (1-27 April. Several males took a more westerly route over the Sahara in spring than in autumn, and in general there were fewer long-distance travels and more frequent shorter stopovers, including one in northern Africa, in spring. The shorter stopovers made spring migration on average faster than autumn migration. There was a strong correlation between the spring departure dates from wintering sites and the arrival dates at the breeding ground. All males had a high migration speed in spring despite large variation in departure dates, indicating a time-minimization strategy to achieve an early arrival at the breeding site; the latter being decisive for high reproductive success in great reed warblers. Our results have important implications for the understanding of long-distance migrants' ability to predict conditions at distant breeding sites and adapt to rapid environmental change.

  5. Annual cycle and migration strategies of a trans-Saharan migratory songbird: a geolocator study in the great reed warbler.

    Science.gov (United States)

    Lemke, Hilger W; Tarka, Maja; Klaassen, Raymond H G; Åkesson, Mikael; Bensch, Staffan; Hasselquist, Dennis; Hansson, Bengt

    2013-01-01

    Recent technological advancements now allow us to obtain geographical position data for a wide range of animal movements. Here we used light-level geolocators to study the annual migration cycle in great reed warblers (Acrocephalus arundinaceus), a passerine bird breeding in Eurasia and wintering in sub-Saharan Africa. We were specifically interested in seasonal strategies in routes and schedules of migration. We found that the great reed warblers (all males, no females were included) migrated from the Swedish breeding site in early August. After spending up to three weeks at scattered stopover sites in central to south-eastern Europe, they resumed migration and crossed the Mediterranean Sea and Sahara Desert without lengthy stopovers. They then spread out over a large overwintering area and each bird utilised two (or even three) main wintering sites that were spatially separated by a distinct mid-winter movement. Spring migration initiation date differed widely between individuals (1-27 April). Several males took a more westerly route over the Sahara in spring than in autumn, and in general there were fewer long-distance travels and more frequent shorter stopovers, including one in northern Africa, in spring. The shorter stopovers made spring migration on average faster than autumn migration. There was a strong correlation between the spring departure dates from wintering sites and the arrival dates at the breeding ground. All males had a high migration speed in spring despite large variation in departure dates, indicating a time-minimization strategy to achieve an early arrival at the breeding site; the latter being decisive for high reproductive success in great reed warblers. Our results have important implications for the understanding of long-distance migrants' ability to predict conditions at distant breeding sites and adapt to rapid environmental change.

  6. Migration routes and staging areas of trans-Saharan Turtle Doves appraised from light-level geolocators.

    Directory of Open Access Journals (Sweden)

    Cyril Eraud

    Full Text Available The identification of migration routes, wintering grounds and stopover sites are crucial issues for the understanding of the Palearctic-African bird migration system as well as for the development of relevant conservation strategies for trans-Saharan migrants. Using miniaturized light-level geolocators we report a comprehensive and detailed year round track of a granivorous trans-Saharan migrant, the European Turtle Dove (Streptopelia turtur. From five recovered loggers, our data provide new insights on migratory journeys and winter destinations of Turtle Doves originating from a breeding population in Western France. Data confirm that Turtle Doves wintered in West Africa. The main wintering area encompassed Western Mali, the Inner Delta Niger and the Malian/Mauritanian border. Some individuals also extended their wintering ranges over North Guinea, North-West of Burkina Faso and the Ivory-Coast. Our results reveal that all individuals did not spend the winter period at a single location; some of them experienced a clear eastward shift of several hundred kilometres. We also found evidence for a loop migration pattern, with a post-breeding migration flyway lying west of the spring route. Finally, we found that on their way back to breeding grounds Turtle Doves needed to refuel after crossing the Sahara desert. Contrary to previous suggestions, our data reveal that birds used stopover sites for several weeks, presumably in Morocco and North Algeria. This later finding is a crucial issue for future conservation strategies because environmental conditions on these staging areas might play a pivotal role in population dynamics of this declining species.

  7. Combination of at-sea activity, geolocation and feather stable isotopes documents where and when seabirds moult

    Directory of Open Access Journals (Sweden)

    Yves eCherel

    2016-02-01

    Full Text Available Key facets of the foraging ecology of seabirds during the inter-breeding period still remain poorly understood because of the difficulty of studying them at sea, including during the energy-demanding moulting stage. Here, the extent to which three sympatric petrels (Antarctic and thin-billed prions, and blue petrel from the subantarctic Kerguelen Islands modify their foraging ecology during moult was investigated using a combination of complementary tools, namely miniaturized saltwater immersion geolocators (GLS and the isotopic method. Firstly, moulting behaviour was first characterized in the blue petrel, a reference species that is known to renew its plumage in autumn. GLS and feather stable isotopes (13C as a proxy of the birds’ foraging habitat indicated that the post-breeding moult of blue petrel occurred in Antarctic waters. Importantly, activity recorders showed that moult was marked by a strong peak in time spent daily sitting on water, which thereafter declined to lower values during the remaining winter months. Secondly, the peak in time spent sitting on water was used as a proxy to characterize the contrasted moult strategies of the two prion species. As blue petrels demonstrated, thin-billed prions moulted during the post-breeding period in cold Antarctic waters where they fed primarily on low trophic level prey, most likely Antarctic krill (15N as a proxy of the birds’ diet. By contrast, Antarctic prions presented an unexpected pre-breeding moult of longer duration that took place further north, in warm subtropical waters. Interestingly, the two Antarctic moulting species, the blue petrel and thin-billed prion, renewed their plumage at the same time and within the same oceanic zone that is likely to be a previously undescribed hot spot of seabird diversity during the Austral autumn. The study contributes to a growing body of evidence that closely-related species exhibit various foraging strategies allowing ecological

  8. A comparative study between xerographic, computer-assisted overlay generation and animated-superimposition methods in bite mark analyses.

    Science.gov (United States)

    Tai, Meng Wei; Chong, Zhen Feng; Asif, Muhammad Khan; Rahmat, Rabiah A; Nambiar, Phrabhakaran

    2016-09-01

    This study was to compare the suitability and precision of xerographic and computer-assisted methods for bite mark investigations. Eleven subjects were asked to bite on their forearm and the bite marks were photographically recorded. Alginate impressions of the subjects' dentition were taken and their casts were made using dental stone. The overlays generated by xerographic method were obtained by photocopying the subjects' casts and the incisal edge outlines were then transferred on a transparent sheet. The bite mark images were imported into Adobe Photoshop® software and printed to life-size. The bite mark analyses using xerographically generated overlays were done by comparing an overlay to the corresponding printed bite mark images manually. In computer-assisted method, the subjects' casts were scanned into Adobe Photoshop®. The bite mark analyses using computer-assisted overlay generation were done by matching an overlay and the corresponding bite mark images digitally using Adobe Photoshop®. Another comparison method was superimposing the cast images with corresponding bite mark images employing the Adobe Photoshop® CS6 and GIF-Animator©. A score with a range of 0-3 was given during analysis to each precision-determining criterion and the score was increased with better matching. The Kruskal Wallis H test showed significant difference between the three sets of data (H=18.761, pbite mark analysis using the computer-assisted animated-superimposition method was the most accurate, followed by the computer-assisted overlay generation and lastly the xerographic method. The superior precision contributed by digital method is discernible despite the human skin being a poor recording medium of bite marks. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  9. DEVELOPMENT OF A NEW GEOSPATIAL DATA SHARING/OVERLAY SYSTEM FOR LAND ENVIRONMENTAL STUDIES – CERES GAIA –

    Directory of Open Access Journals (Sweden)

    R. Tateishi

    2012-07-01

    Full Text Available A new geospatial data sharing/overlay system, CEReS Gaia, has developed. The purpose of the system development is to promote land surface environmental studies. The system has developed to meet the requirements by academic users who wish easy data analysis by using his/her own data with existing other data. The system has the following features; a internationally unlimited expansion of servers, b multi-language capability (currently, only English, c free access without user registration, d data upload/download by registered users, e capability to overlay user’s data on other registered data, f option of open or selective data distribution.

  10. Loss Performance Modeling for Hierarchical Heterogeneous Wireless Networks With Speed-Sensitive Call Admission Control

    DEFF Research Database (Denmark)

    Huang, Qian; Huang, Yue-Cai; Ko, King-Tim

    2011-01-01

    A hierarchical overlay structure is an alternative solution that integrates existing and future heterogeneous wireless networks to provide subscribers with better mobile broadband services. Traffic loss performance in such integrated heterogeneous networks is necessary for an operator's network...... dimensioning and planning. This paper investigates the computationally efficient loss performance modeling for multiservice in hierarchical heterogeneous wireless networks. A speed-sensitive call admission control (CAC) scheme is considered in our model to assign overflowed calls to appropriate tiers...

  11. Enabling Wireless Power Transfer in Cellular Networks: Architecture, Modeling and Deployment

    OpenAIRE

    Huang, Kaibin; Lau, Vincent K. N.

    2012-01-01

    Microwave power transfer (MPT) delivers energy wirelessly from stations called power beacons (PBs) to mobile devices by microwave radiation. This provides mobiles practically infinite battery lives and eliminates the need of power cords and chargers. To enable MPT for mobile charging, this paper proposes a new network architecture that overlays an uplink cellular network with randomly deployed PBs for powering mobiles, called a hybrid network. The deployment of the hybrid network under an out...

  12. Analyzing the Bitcoin Network: The First Four Years

    Directory of Open Access Journals (Sweden)

    Matthias Lischke

    2016-03-01

    Full Text Available In this explorative study, we examine the economy and transaction network of the decentralized digital currency Bitcoin during the first four years of its existence. The objective is to develop insights into the evolution of the Bitcoin economy during this period. For this, we establish and analyze a novel integrated dataset that enriches data from the Bitcoin blockchain with off-network data such as business categories and geo-locations. Our analyses reveal the major Bitcoin businesses and markets. Our results also give insights on the business distribution by countries and how businesses evolve over time. We also show that there is a gambling network that features many very small transactions. Furthermore, regional differences in the adoption and business distribution could be found. In the network analysis, the small world phenomenon is investigated and confirmed for several subgraphs of the Bitcoin network.

  13. Accelerated testing for studying pavement design and performance (FY 2000) : effectiveness of fiber reinforced and plain, ultra-thin concrete overlays on Portland Cement Concrete Pavement (PCCP).

    Science.gov (United States)

    2003-11-01

    The objective of the research was to compare the performance of fiber reinforced and plain PCC concrete overlay when used as a thin non-dowelled overlay on top of a rubblized, distressed concrete pavement. The experiment was conducted at the Accelera...

  14. Behaviour of Parallel Coupled Microstrip Band Pass Filter and Simple Microstripline due to Thin-Film Al2O3 Overlay

    Directory of Open Access Journals (Sweden)

    S. B. Rane

    1996-01-01

    Full Text Available The X-band behaviour of a seven-section parallel-coupled microstrip band pass filter and microstripline due to thin-film Al2O3 overlay of different thickness is reported in this paper. This Al2O3 film can give a homogeneous overlay structure. There is a substantial increase in the bandwidth due to the overlay, the pass band extending towards higher frequency side. In most of the cases, an increase in the pass band transmittance of a microstripline also increases due to a thin-film Al2O3 overlay, especially for frequencies less than 9.0 GHz. At higher frequencies, random variations are observed. It is felt that thin-film overlays can be used to modify the microstripline circuit properties, thereby avoiding costly and time consuming elaborate design procedures.

  15. Processing moldable tasks on the grid: Late job binding with lightweight user-level overlay

    CERN Document Server

    Moscicki, J T; Sloot, P M A; Lamanna, M

    2011-01-01

    Independent observations and everyday user experience indicate that performance and reliability of large grid infrastructures may suffer from large and unpredictable variations. In this paper we study the impact of the job queuing time on processing of moldable tasks which are commonly found in large-scale production grids. We use the mean value and variance of makespan as the quality of service indicators. We develop a general task processing model to provide a quantitative comparison between two models: early and late job binding in a user-level overlay applied to the EGEE Grid infrastructure. We find that the late-binding model effectively defines a transformation of the distribution of makespan according to the Central Limit Theorem. As demonstrated by Monte Carlo simulations using real job traces, this transformation allows to substantially reduce the mean value and variance of makespan. For certain classes of applications task granularity may be adjusted such that a speedup of an order of magnitude or m...

  16. Application of Groundwater Vulnerability Overlay and Index Methods to the Jijel Plain Area (Algeria).

    Science.gov (United States)

    Boufekane, Abdelmadjid; Saighi, Omar

    2018-01-01

    Today, scientists are deeply concerned by the vulnerability of groundwater reservoirs to pollution. Relatively simple overlay and index methods can be used to produce groundwater vulnerability maps in geographic information system. In addition, this study deals with contamination from nonpoint sources. In this study, two such models, DRASTIC and GOD, were applied in the Jijel Plain area of northeast Algeria and compared with measured groundwater nitrate concentrations. This showed that results from DRASTIC were better than GOD, 69% correlation with nitrate compared to 56%. DRASTIC was better able to identify vulnerable zones along the river valleys. The DRASTIC model was then modified using the nitrate concentrations to optimize the rating score given within each parameter range and sensitivity analysis to change the weighting given for each parameter. These combined changes gave a final Pearson's correlation of 83% with nitrate. This showed that recharge, aquifer type, and topography were the key factors in controlling vulnerability to nitrate pollution. © 2017, National Ground Water Association.

  17. Low Pressure Plasma Sprayed Overlay Coatings for GRCop-84 Combustion Chamber Liners for Reusable Launch Vehicles

    Science.gov (United States)

    Raj, S. V.; Barrett, C.; Ghosn, L. J.; Lerch, B.; Robinson,; Thorn, G.

    2005-01-01

    An advanced Cu-8(at.%)Cr-4%Nb alloy developed at NASA's Glenn Research Center, and designated as GRCop-84, is currently being considered for use as combustor chamber liners and nozzle ramps in NASA s future generations of reusable launch vehicles (RLVs). However, past experience has shown that unprotected copper alloys undergo an environmental attack called "blanching" in rocket engines using liquid hydrogen as fuel and liquid oxygen as the oxidizer. Potential for sulfidation attack of the liners in hydrocarbon-fueled engines is also of concern. Protective overlay coatings alloys are being developed for GRCop-84. The development of this coatings technology has involved a combination of modeling, coatings development and characterization, and process optimization. Coatings have been low pressure plasma sprayed on GRCop-84 substrates of various geometries and shapes. Microstructural, mechanical property data and thermophysical results on the coated substrates are presented and discussed.

  18. Interactive Overlays: A New Method for Generating Global Journal Maps from Web-of-Science Data

    CERN Document Server

    Leydesdorff, Loet

    2011-01-01

    Recent advances in methods and techniques enable us to develop an interactive overlay to the global map of science based on aggregated citation relations among the 9,162 journals contained in the Science Citation Index and Social Science Citation Index 2009 combined. The resulting mapping is provided by VOSViewer. We first discuss the pros and cons of the various options: cited versus citing, multidimensional scaling versus spring-embedded algorithms, VOSViewer versus Gephi, and the various clustering algorithms and similarity criteria. Our approach focuses on the positions of journals in the multidimensional space spanned by the aggregated journal-journal citations. A number of choices can be left to the user, but we provide default options reflecting our preferences. Some examples are also provided; for example, the potential of using this technique to assess the interdisciplinarity of organizations and/or document sets.

  19. Large-Scale Overlays and Trends: Visually Mining, Panning and Zooming the Observable Universe.

    Science.gov (United States)

    Luciani, Timothy Basil; Cherinka, Brian; Oliphant, Daniel; Myers, Sean; Wood-Vasey, W Michael; Labrinidis, Alexandros; Marai, G Elisabeta

    2014-07-01

    We introduce a web-based computing infrastructure to assist the visual integration, mining and interactive navigation of large-scale astronomy observations. Following an analysis of the application domain, we design a client-server architecture to fetch distributed image data and to partition local data into a spatial index structure that allows prefix-matching of spatial objects. In conjunction with hardware-accelerated pixel-based overlays and an online cross-registration pipeline, this approach allows the fetching, displaying, panning and zooming of gigabit panoramas of the sky in real time. To further facilitate the integration and mining of spatial and non-spatial data, we introduce interactive trend images-compact visual representations for identifying outlier objects and for studying trends within large collections of spatial objects of a given class. In a demonstration, images from three sky surveys (SDSS, FIRST and simulated LSST results) are cross-registered and integrated as overlays, allowing cross-spectrum analysis of astronomy observations. Trend images are interactively generated from catalog data and used to visually mine astronomy observations of similar type. The front-end of the infrastructure uses the web technologies WebGL and HTML5 to enable cross-platform, web-based functionality. Our approach attains interactive rendering framerates; its power and flexibility enables it to serve the needs of the astronomy community. Evaluation on three case studies, as well as feedback from domain experts emphasize the benefits of this visual approach to the observational astronomy field; and its potential benefits to large scale geospatial visualization in general.

  20. Minus Piggyback Lens Overlaying ReSTOR® Multifocal Lens in High Myopia

    Directory of Open Access Journals (Sweden)

    Isha Gupta

    2013-06-01

    Full Text Available Background: We report the case of a 40-year-old female patient treated with implantation of the Acrysof® IQ ReSTOR® lens (Alcon, Fort Worth, Tex., USA with overlaying Acrysof EXpand® minus piggyback lens (Alcon. Methods: The patient had high myopia and was diagnosed with presbyopia and bilateral posterior subcapsular cataract. She desired to be spectacle-free and opted to undergo bilateral placement of the ReSTOR multifocal lens. The necessary intraocular lens (IOL power was +3.5 in the right eye and +4.0 in the left eye, though the range of commercially available ReSTOR lenses is +6.0 to +34.0 D. In order to achieve emmetropia in this case of high myopia, it was determined that an EXpand minus piggyback lens would be necessary. Results: Implantation of the ReSTOR lens with overlaying EXpand minus piggyback lens was performed successfully and without complication. At 5 months postoperatively, the patient had 20/20 uncorrected visual acuity in both eyes. She reported a high level of satisfaction and was able to return to her daily activities including reading and driving without spectacles. Conclusion: We report successful primary implantation of AcrySof EXpand minus piggyback lenses overlying the AcrySof IQ ReSTOR lens in a patient with high myopia. Long-term follow-up and further evaluation is necessary to establish piggyback IOL implantation with multifocal IOL as an accepted treatment for high myopia with presbyopia.

  1. Influence of overlay restorative materials and load cusps on the fatigue resistance of endodontically treated molars.

    Science.gov (United States)

    Magne, Pascal; Knezevic, Alena

    2009-10-01

    To assess the influence of restorative materials and load cusps on the fatigue resistance of endodontically treated molars. Thirty extracted molars received root canal treatment followed by a standardized tooth preparation (3-mm cuspal reduction and immediate dentin sealing). Twenty Cerec 3 overlays (Sirona Dental Systems) were milled in the ceramic Vita MKII block (Vident; groups MKIIGL and MKIIGL-Z, oven-glazed), and 10 restorations were duplicated with a composite resin (Miris 2, Coltane/Whaledent; group M2). The fitting surfaces of the restorations were hydrofluoric acid etched (porcelain only) and silanated. Preparations were airborne-particle abraded and etched. All restorations were luted with preheated Filtek Z100 (3M ESPE) and subjected to cyclic isometric chewing (5 Hz) starting at 200 N (5,000 cycles), followed by stages of 400, 600, 800, 1,000, 1,200, and 1,400 N at a maximum of 30,000 cycles each. A stainless steel load sphere was used for groups MKIIGL and M2, while a composite resin load sphere was used in group MKIIGL-Z. All samples were loaded until fracture or to a maximum of 185,000 cycles. Groups were compared using the Kaplan-Meier survival curves (P = .05). None of the molars restored with porcelain withstood all 185,000 loading cycles (survival = 0%). The mean fracture load for MKIIGL was 1,060 N and for MKIIGL-Z, 1,280 N. In group M2, the survival rate was 50%. The rate of fracture below the CEJ was 40%, 30%, and 20% for MKIIGL, MKIIGL-Z, and M2, respectively. Miris 2 overlays showed higher fatigue resistance than MKII porcelain (P = .01) when loaded with a stainless steel antagonist.

  2. An Efficient, Scalable and Robust P2P Overlay for Autonomic Communication

    Science.gov (United States)

    Li, Deng; Liu, Hui; Vasilakos, Athanasios

    The term Autonomic Communication (AC) refers to self-managing systems which are capable of supporting self-configuration, self-healing and self-optimization. However, information reflection and collection, lack of centralized control, non-cooperation and so on are just some of the challenges within AC systems. Since many self-* properties (e.g. selfconfiguration, self-optimization, self-healing, and self-protecting) are achieved by a group of autonomous entities that coordinate in a peer-to-peer (P2P) fashion, it has opened the door to migrating research techniques from P2P systems. P2P's meaning can be better understood with a set of key characteristics similar to AC: Decentralized organization, Self-organizing nature (i.e. adaptability), Resource sharing and aggregation, and Fault-tolerance. However, not all P2P systems are compatible with AC. Unstructured systems are designed more specifically than structured systems for the heterogeneous Internet environment, where the nodes' persistence and availability are not guaranteed. Motivated by the challenges in AC and based on comprehensive analysis of popular P2P applications, three correlative standards for evaluating the compatibility of a P2P system with AC are presented in this chapter. According to these standards, a novel Efficient, Scalable and Robust (ESR) P2P overlay is proposed. Differing from current structured and unstructured, or meshed and tree-like P2P overlay, the ESR is a whole new three dimensional structure to improve the efficiency of routing, while information exchanges take in immediate neighbors with local information to make the system scalable and fault-tolerant. Furthermore, rather than a complex game theory or incentive mechanism, asimple but effective punish mechanism has been presented based on a new ID structure which can guarantee the continuity of each node's record in order to discourage negative behavior on an autonomous environment as AC.

  3. Overlay accuracy on a flexible web with a roll printing process based on a roll-to-roll system.

    Science.gov (United States)

    Chang, Jaehyuk; Lee, Sunggun; Lee, Ki Beom; Lee, Seungjun; Cho, Young Tae; Seo, Jungwoo; Lee, Sukwon; Jo, Gugrae; Lee, Ki-yong; Kong, Hyang-Shik; Kwon, Sin

    2015-05-01

    For high-quality flexible devices from printing processes based on Roll-to-Roll (R2R) systems, overlay alignment during the patterning of each functional layer poses a major challenge. The reason is because flexible substrates have a relatively low stiffness compared with rigid substrates, and they are easily deformed during web handling in the R2R system. To achieve a high overlay accuracy for a flexible substrate, it is important not only to develop web handling modules (such as web guiding, tension control, winding, and unwinding) and a precise printing tool but also to control the synchronization of each unit in the total system. A R2R web handling system and reverse offset printing process were developed in this work, and an overlay between the 1st and 2nd layers of ±5μm on a 500 mm-wide film was achieved at a σ level of 2.4 and 2.8 (x and y directions, respectively) in a continuous R2R printing process. This paper presents the components and mechanisms used in reverse offset printing based on a R2R system and the printing results including positioning accuracy and overlay alignment accuracy.

  4. Interactive overlays of journals and the measurement of interdisciplinarity on the basis of aggregated journal-journal citations

    NARCIS (Netherlands)

    Leydesdorff, L.; Rafols, I.; Chen, C.

    2013-01-01

    Using the option Analyze Results with the Web of Science, one can directly generate overlays onto global journal maps of science. The maps are based on the 10,000+ journals contained in the Journal Citation Reports (JCR) of the Science and Social Sciences Citation Indices (2011). The disciplinary

  5. Journal maps, interactive overlays, and the measurement of interdisciplinarity on the basis of Scopus data (1996-2012)

    NARCIS (Netherlands)

    Leydesdorff, L.; de Moya-Anegón, F.; Guerrero-Bote, V.P.

    2015-01-01

    Using Scopus data, we construct a global map of science based on aggregated journal-journal citations from 1996-2012 (N of journals = 20,554). This base map enables users to overlay downloads from Scopus interactively. Using a single year (e.g., 2012), results can be compared with mappings based on

  6. Experimental and numerical analyses of PCC overlays on PCC slabs-on-grade subjected to climatic loading

    National Research Council Canada - National Science Library

    Kim, Seong-Min; Kim Nelson, Patricia

    2004-01-01

    ... of bonded Portland cement concrete (PCC) overlays on PCC slabs-on-grade. Delamination is often due to an inadequacy in one (or more) pavement design variables: the pavement design, the Portland cement materials and mix design, the climatic conditions at the time of construction, and the methods of construction. This led the Federal Highway Ad...

  7. Fracture patterns of glass-ionomer cement overlays versus stainless steel bands during endodontic treatment: an ex-vivo study.

    Science.gov (United States)

    Pakdeethai, S; Abuzar, M; Parashos, P

    2013-12-01

    To compare fracture patterns of posterior teeth temporized with: mesio-occlusal-distal (MOD) glass-ionomer cement (GIC) interim restorations, stainless steel (SS) bands, GIC dome overlays and GIC dome overlays with occlusal temporary restorations. The root canals of 92 extracted human premolars and molars were prepared with rotary NiTi instruments and dressed with calcium hydroxide paste prior to cavity preparation for standardized MOD restorations. Teeth were divided into four groups (n = 23) and temporarily restored with: GIC interim restorations (GIC group), stainless steel bands (SS group), GIC dome overlays (GIC-O group) or GIC dome overlays with intermediate restorative material (IRM) in the access cavities (GIC-IRM group). Teeth were subjected to compressive axial load until fracture; fracture forces and fracture modes were recorded. Statistical analysis included Kaplan-Meier plots, Cox proportional hazards model, one-way analysis of variance, chi-square and Fisher's exact tests. There was a significantly higher risk of failure in the GIC group compared with the SS (P steel bands may only need to be used in extensively broken-down teeth or in the presence of parafunctional habits. © 2013 International Endodontic Journal. Published by John Wiley & Sons Ltd.

  8. Microstructure and Mechanical Properties of Inconel 625 Alloy on Low Carbon Steel by Heat Treatment after Overlay Welding

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Seungpil; Jang, Jaeho; Kim, Jungsoo; Kim, Byung Jun; Sohn, Keun Yong; Nam, Dae-Geun [Korea Institute of Industrial Technology, Busan (Korea, Republic of)

    2016-08-15

    Overlay welding technique is one of methods used to improve metal mechanical properties such as strength, toughness and corrosion resistance. Generally, Inconel 625 alloy is used for overlay welding layer on low carbon steels for economic consideration. However, the method produces some problems in the microstructure of the cast structure and some defects, caused by the elevated temperatures of the overlay process. To resolve these problems, heat treatments are required. In this study, Inconel 625 alloy was welded on a low carbon steel by the overlay welding process to investigate the resulting microstructure and mechanical properties. A double heat treatment was performed to improve the mechanical properties of the welding and substrate layers. It was found that Inconel 625 alloy had an austenite microstructure after the first heat treatment, but the low carbon steel had a ferrite-pearlite microstructure after the second heat treatment. After the double heat treatment, the sample showed the optimum hardness because of grain refinement and homogenization of the microstructure.

  9. Evaluation of iron aluminide weld overlays for erosion - corrosion resistant boiler tube coatings in low NO{sub x} boilers

    Energy Technology Data Exchange (ETDEWEB)

    DuPont, J.N.; Banovic, S.W.; Marder, A.R. [Lehigh Univ., Bethlehem, PA (United States)

    1996-08-01

    Low NOx burners are being installed in many fossil fired power plants in order to comply with new Clean Air Regulations. Due to the operating characteristics of these burners, boiler tube sulfidation corrosion is often enhanced and premature tube failures can occur. Failures due to oxidation and solid particle erosion are also a concern. A program was initiated in early 1996 to evaluate the use of iron aluminide weld overlays for erosion/corrosion protection of boiler tubes in Low NOx boilers. Composite iron/aluminum wires will be used with the Gas Metal Arc Welding (GMAW) process to prepare overlays on boiler tubes steels with aluminum contents from 8 to 16wt%. The weldability of the composite wires will be evaluated as a function of chemical composition and welding parameters. The effect of overlay composition on corrosion (oxidation and sulfidation) and solid particle erosion will also be evaluated. The laboratory studies will be complemented by field exposures of both iron aluminide weld overlays and co-extruded tubing under actual boiler conditions.

  10. Migration routes and strategies in a highly aerial migrant, the common swift Apus apus, revealed by light-level geolocators.

    Directory of Open Access Journals (Sweden)

    Susanne Åkesson

    Full Text Available The tracking of small avian migrants has only recently become possible by the use of small light-level geolocators, allowing the reconstruction of whole migration routes, as well as timing and speed of migration and identification of wintering areas. Such information is crucial for evaluating theories about migration strategies and pinpointing critical areas for migrants of potential conservation value. Here we report data about migration in the common swift, a highly aerial and long-distance migrating species for which only limited information based on ringing recoveries about migration routes and wintering areas is available. Six individuals were successfully tracked throughout a complete migration cycle from Sweden to Africa and back. The autumn migration followed a similar route in all individuals, with an initial southward movement through Europe followed by a more southwest-bound course through Western Sahara to Sub-Saharan stopovers, before a south-eastward approach to the final wintering areas in the Congo basin. After approximately six months at wintering sites, which shifted in three of the individuals, spring migration commenced in late April towards a restricted stopover area in West Africa in all but one individual that migrated directly towards north from the wintering area. The first part of spring migration involved a crossing of the Gulf of Guinea in those individuals that visited West Africa. Spring migration was generally wind assisted within Africa, while through Europe variable or head winds were encountered. The average detour at about 50% could be explained by the existence of key feeding sites and wind patterns. The common swift adopts a mixed fly-and-forage strategy, facilitated by its favourable aerodynamic design allowing for efficient use of fuel. This strategy allowed swifts to reach average migration speeds well above 300 km/day in spring, which is higher than possible for similar sized passerines. This study

  11. Migration routes and strategies in a highly aerial migrant, the common swift Apus apus, revealed by light-level geolocators.

    Science.gov (United States)

    Åkesson, Susanne; Klaassen, Raymond; Holmgren, Jan; Fox, James W; Hedenström, Anders

    2012-01-01

    The tracking of small avian migrants has only recently become possible by the use of small light-level geolocators, allowing the reconstruction of whole migration routes, as well as timing and speed of migration and identification of wintering areas. Such information is crucial for evaluating theories about migration strategies and pinpointing critical areas for migrants of potential conservation value. Here we report data about migration in the common swift, a highly aerial and long-distance migrating species for which only limited information based on ringing recoveries about migration routes and wintering areas is available. Six individuals were successfully tracked throughout a complete migration cycle from Sweden to Africa and back. The autumn migration followed a similar route in all individuals, with an initial southward movement through Europe followed by a more southwest-bound course through Western Sahara to Sub-Saharan stopovers, before a south-eastward approach to the final wintering areas in the Congo basin. After approximately six months at wintering sites, which shifted in three of the individuals, spring migration commenced in late April towards a restricted stopover area in West Africa in all but one individual that migrated directly towards north from the wintering area. The first part of spring migration involved a crossing of the Gulf of Guinea in those individuals that visited West Africa. Spring migration was generally wind assisted within Africa, while through Europe variable or head winds were encountered. The average detour at about 50% could be explained by the existence of key feeding sites and wind patterns. The common swift adopts a mixed fly-and-forage strategy, facilitated by its favourable aerodynamic design allowing for efficient use of fuel. This strategy allowed swifts to reach average migration speeds well above 300 km/day in spring, which is higher than possible for similar sized passerines. This study demonstrates that new

  12. Pengembangan Sistem Informasi Geografis Berbasis Node.JS untuk Pemetaan Mesin dan Tracking Engineer dengan Pemanfaatan Geolocation pada PT IBM Indonesia

    Directory of Open Access Journals (Sweden)

    RACHMAT FAJRIN

    2017-09-01

    Full Text Available PT IBM memiliki banyak klien di Indonesia, ini membuat persebaran produk (dalam hal ini mesin atm yang semakin meluas di wilayah Indonesia. Hal ini memicu PT IBM untuk menempatkan engineer dibanyak wilayah untuk memenuhi kebutuhan services dan maintenance. Untuk itu dalam penelitian ini dikembangkan sebuah sistem informasi geografis untuk pemetaan mesin dan tracking engineer dengan pemanfaatan geolocation yang bertujuan untuk menampilkan peta digital beserta lokasi mesin dan engineer di seluruh Indonesia, yang akan memudahkan PT IBM dalam pemberian tugas kepada engineer untuk services dan maintenance ke lokasi mesin terdekat. Sistem ini dibangun menggunakan beberapa software open source yaitu, Node.JS dan Express.JS yang merupakan server-side javascript web platform, Handlebars untuk template engine, MySQL sebagai database storage, Postman yang berfungsi sebagai API (Application Program Interface testing, Google Maps API untuk implementasi peta digital dan juga Firebase Cloud Messaging (FCM untuk platform mengirim notifikasi dari web ke device engineer.Pengembangan Sistem Informasi Geografis Berbasis Node.JS untuk Pemetaan Mesin dan Tracking Engineer dengan Pemanfaatan Geolocation pada PT IBM Indonesia

  13. Social Networking Privacy—Who’s Stalking You?

    OpenAIRE

    Gan, Diane; Lily R. Jenkins

    2015-01-01

    This research investigates the privacy issues that exist on social networking sites. It is reasonable to assume that many Twitter users are unaware of the dangers of uploading a tweet to their timeline which can be seen by anyone. Enabling geo-location tagging on tweets can result in personal information leakage, which the user did not intend to be public and which can seriously affect that user’s privacy and anonymity online. This research demonstrates that key information can easily be retr...

  14. Coloured overlays and precision-tinted lenses: poor repeatability in a sample of adults and children diagnosed with visual stress

    Science.gov (United States)

    Suttle, Catherine M; Barbur, John; Conway, Miriam L

    2017-07-01

    Visual stress consists of perceived distortions or discomfort while reading. It is claimed that these symptoms are alleviated by viewing through coloured lenses or overlays, with a specific colour required for each individual. This has been explained on the basis of altered visual cortex excitation as affected by the spectral content of the viewing light. If symptoms are indeed alleviated by a particular colour that has an impact on the individual's visual system, we would expect that selection of the most beneficial colour would be repeatable. The aim of this study was to determine whether this is the case. Twenty-one participants (mean age 26 years (range 8-55 years); 12 female, nine male) with visual stress and no other uncorrected ocular or visual anomaly were recruited. Each participant selected the colour most beneficial in alleviating their symptoms from a standard set of 10 coloured overlays, and underwent intuitive colorimetry in which the most beneficial of a wide range of chromatic illuminance settings was selected. Without prescribing an overlay at the first appointment, this process was repeated on a second occasion at a mean of 25 days later. About half of the participants (n = 10) chose the same (n = 7) or similar (with one common colour in both choices; n = 3) coloured overlay on the two occasions, while 11 participants chose a completely different overlay colour. Across all participants, the colorimetry setting shifted by, on average, 9.6 just noticeable differences, indicating that the colours were perceptually very different. These findings suggest that people with visual stress are unlikely to find exactly the same colour to be optimal on different occasions, and raise questions about the need for precise colour specification in tinted lenses for visual stress. © 2017 The Authors Ophthalmic & Physiological Optics © 2017 The College of Optometrists.

  15. A Facile Surface Passivation of Hematite Photoanodes with TiO2 Overlayers for Efficient Solar Water Splitting.

    Science.gov (United States)

    Ahmed, Mahmoud G; Kretschmer, Imme E; Kandiel, Tarek A; Ahmed, Amira Y; Rashwan, Farouk A; Bahnemann, Detlef W

    2015-11-04

    The surface modification of semiconductor photoelectrodes with passivation overlayers has recently attracted great attention as an effective strategy to improve the charge-separation and charge-transfer processes across semiconductor-liquid interfaces. It is usually carried out by employing the sophisticated atomic layer deposition technique, which relies on reactive and expensive metalorganic compounds and vacuum processing, both of which are significant obstacles toward large-scale applications. In this paper, a facile water-based solution method has been developed for the modification of nanostructured hematite photoanode with TiO2 overlayers using a water-soluble titanium complex (i.e., titanium bis(ammonium lactate) dihydroxide, TALH). The thus-fabricated nanostructured hematite photoanodes have been characterized by X-ray diffraction, scanning electron microscopy, and X-ray photoelectron spectroscopy. Photoelectrochemical measurements indicated that a nanostructured hematite photoanodes modified with a TiO2 overlayer exhibited a photocurrent response ca. 4.5 times higher (i.e., 1.2 mA cm(-2) vs RHE) than that obtained on the bare hematite photoanode (i.e., 0.27 mA cm(-2) vs RHE) measured under standard illumination conditions. Moreover, a cathodic shift of ca. 190 mV in the water oxidation onset potential was achieved. These results are discussed and explored on the basis of steady-state polarization, transient photocurrent response, open-circuit potential, intensity-modulated photocurrent spectroscopy, and impedance spectroscopy measurements. It is concluded that the TiO2 overlayer passivates the surface states and suppresses the surface electron-hole recombination, thus increasing the generated photovoltage and the band bending. The present method for the hematite electrode modification with a TiO2 overlayer is effective and simple and might find broad applications in the development of stable and high-performance photoelectrodes.

  16. Social Networking Privacy—Who’s Stalking You?

    Directory of Open Access Journals (Sweden)

    Diane Gan

    2015-03-01

    Full Text Available This research investigates the privacy issues that exist on social networking sites. It is reasonable to assume that many Twitter users are unaware of the dangers of uploading a tweet to their timeline which can be seen by anyone. Enabling geo-location tagging on tweets can result in personal information leakage, which the user did not intend to be public and which can seriously affect that user’s privacy and anonymity online. This research demonstrates that key information can easily be retrieved using the starting point of a single tweet with geo-location turned on. A series of experiments have been undertaken to determine how much information can be obtained about a particular individual using only social networking sites and freely available mining tools. The information gathered enabled the target subjects to be identified on other social networking sites such as Foursquare, Instagram, LinkedIn, Facebook and Google+, where more personal information was leaked. The tools used are discussed, the results of the experiments are presented and the privacy implications are examined.

  17. Influence of geolocation and ethnicity on the phenotypic expression of primary Sjogren's syndrome at diagnosis in 8310 patients : a cross-sectional study from the Big Data Sjogren Project Consortium

    NARCIS (Netherlands)

    Brito-Zeron, Pilar; Acar-Denizli, Nihan; Zeher, Margit; Rasmussen, Astrid; Seror, Raphaele; Theander, Elke; Li, Xiaomei; Baldini, Chiara; Gottenberg, Jacques-Eric; Danda, Debashish; Quartuccio, Luca; Priori, Roberta; Hernandez-Molina, Gabriela; Kruize, Aike A.; Valim, Valeria; Kvarnstrom, Marika; Sene, Damien; Gerli, Roberto; Praprotnik, Sonja; Isenberg, David; Solans, Roser; Rischmueller, Maureen; Kwok, Seung-Ki; Nordmark, Gunnel; Suzuki, Yasunori; Giacomelli, Roberto; Devauchelle-Pensec, Valerie; Bombardieri, Michele; Hofauer, Benedikt; Bootsma, Hendrika; Brun, Johan G.; Fraile, Guadalupe; Carsons, Steven E.; Gheita, Tamer A.; Morel, Jacques; Vollenveider, Cristina; Atzeni, Fabiola; Retamozo, Soledad; Horvath, Ildiko Fanny; Sivils, Kathy; Mandl, Thomas; Sandhya, Pulukool; De Vita, Salvatore; Sanchez-Guerrero, Jorge; van der Heijden, Eefje; Moca Trevisani, Virginia Fernandes; Wahren-Herlenius, Marie; Mariette, Xavier; Ramos-Casals, Manuel

    Objectives To analyse the influence of geolocation and ethnicity on the clinical presentation of primary Sjgren's syndrome (SjS) at diagnosis. Methods The Big Data Sjogren Project Consortium is an international, multicentre registry designed in 2014. By January 2016, 20 centres from five continents

  18. Literature, Geolocation and Wikidata

    DEFF Research Database (Denmark)

    Nielsen, Finn Årup

    2016-01-01

    Littar was the second-prize winning entry in an app competition. It implemented a system for visualizing places mentioned in individual literary works. Wikidata acted as the backend for the system. Here I describe the Littar system and also some of the issues I encountered while developing the sy...... the system: How locations and literature can be related, what types of location-literature relations are possible within Wiki-data, what limitations there are and what questions we may ask once we have enough data in Wikidata....

  19. Investigation of the weldability of iron-aluminum-chromium overlay coatings for corrosion protection in oxidizing/sulfidizing environments

    Science.gov (United States)

    Regina, Jonathan R.

    The current study investigated the effect of chromium additions on the hydrogen cracking susceptibility of Fe-Al weld overlay claddings containing chromium additions. It was found that the weldability of FeAlCr claddings was a function of both the aluminum and chromium concentrations of the weld coatings. Weld overlay compositions that were not susceptible to hydrogen cracking were identified and the underlying mechanism behind the hydrogen cracking phenomenon was investigated further. It was concluded that the cracking behavior of the FeAlCr welds depended strongly on the microstructure of the weld fusion zone. Although it was found that the cracking susceptibility was influenced by the presence of Fe-Al intermetallic phases (namely Fe3 Al and FeAl), the cracking behavior of FeAlCr weld overlay claddings also depended on the size and distribution of carbide and oxide particles present within the weld structure. These particles acted as hydrogen trapping sites, which are areas where free hydrogen segregates and can no longer contribute to the hydrogen embrittlement of the metal. It was determined that in practical applications of these FeAlCr weld overlay coatings, carbon should be present within these welds to reduce the amount of hydrogen available for hydrogen cracking. Based on the weldability results of the FeAlCr weld claddings, coating compositions that were able to be deposited crack-free were used for long-term corrosion testing in a simulated low NOx environment. These alloys were compared to a Ni-based superalloy (622), which is commonly utilized as boiler tube coatings in power plant furnaces for corrosion protection. It was found that the FeAlCr alloys demonstrated superior corrosion resistance when compared to the Ni-based superalloy. Due to the excellent long-term corrosion behavior of FeAlCr weld overlays that were immune to hydrogen cracking, it was concluded that select FeAlCr weld overlay compositions would make excellent corrosion resistant

  20. Analysing human mobility patterns of hiking activities through complex network theory.

    Science.gov (United States)

    Lera, Isaac; Pérez, Toni; Guerrero, Carlos; Eguíluz, Víctor M; Juiz, Carlos

    2017-01-01

    The exploitation of high volume of geolocalized data from social sport tracking applications of outdoor activities can be useful for natural resource planning and to understand the human mobility patterns during leisure activities. This geolocalized data represents the selection of hike activities according to subjective and objective factors such as personal goals, personal abilities, trail conditions or weather conditions. In our approach, human mobility patterns are analysed from trajectories which are generated by hikers. We propose the generation of the trail network identifying special points in the overlap of trajectories. Trail crossings and trailheads define our network and shape topological features. We analyse the trail network of Balearic Islands, as a case of study, using complex weighted network theory. The analysis is divided into the four seasons of the year to observe the impact of weather conditions on the network topology. The number of visited places does not decrease despite the large difference in the number of samples of the two seasons with larger and lower activity. It is in summer season where it is produced the most significant variation in the frequency and localization of activities from inland regions to coastal areas. Finally, we compare our model with other related studies where the network possesses a different purpose. One finding of our approach is the detection of regions with relevant importance where landscape interventions can be applied in function of the communities.

  1. Equipment stainless steel entire versus steels bimetallics clad or overlay; Utilizacao de equipamentos de processo construidos em aco inoxidavel integral versus acos bimetalicos cladeado ou 'overlay'

    Energy Technology Data Exchange (ETDEWEB)

    Batista, Itamar da Silva; Lima, Jadival Carneiro de; Leal, Murilo Fonseca; Cardoso, Amauri dos Santos; Jorjan, Roberto [PETROBRAS S.A., Sao Francisco do Conde, BA (Brazil). Refinaria Landulfo Alves Mataripen (RLAM)

    2008-07-01

    This study does not recommend the use of a pressure vessel made of integral stainless steel, due to the failure mechanisms under stress corrosion assisted by chlorides or polythionic acid. Are presented case studies of literature and analysis of reports of proceedings of RLAM reactors, showing that the materials produced by bimetallic clad overlay or are more appropriate, in terms of integrity, for use in equipment that the internal environment requires austenitic stainless steel specification.

  2. Stellite weld overlay of valves: analysis of the damaging process; Depots stellites de robinetterie: synthese des mecanismes de degradation

    Energy Technology Data Exchange (ETDEWEB)

    Cleurennec, M.; Cauvin, R. [Electricite de France (EDF/GDL), 93 - Saint-Denis (France). Groupe des Labs

    1998-07-01

    Up to day, morethan 150 expertises have been performed on Stellite sealing surfaces of valves from EDF PWR units. These expertises deal with valves coming from many different pipes of the primary circuit. Expertises are decided following leaks during operation or defects observed during maintenance. The first step of our work leads to a characterization and classification of the different types of defects of Stellite weld overlay. We mainly find two types of defects: defects produced during fabrication, linked to the welding process, and defects developed during operation, mainly mechanical cracking and generalized corrosion. A data base was created; the analysis shows a correlation between fabrication defects and severe operating loadings or environments giving a qualitative understanding of damaging process of Stellites weld overlay. The corrective solutions involve both conception or fabrication and operating conditions. (authors)

  3. Pavement structure mechanics response of flexible on semi-flexible overlay that based on the old cement concrete pavement damage

    Directory of Open Access Journals (Sweden)

    Jiang Ruinan

    2015-01-01

    Full Text Available The old cement pavement damage status directly affect the design of the paving renovation. Based on the state of the old road investigation, combined with the research data at home and abroad, use the control index that average deflection, deflection value and CBR value to determine the reasonable time to overlay. Draw up the typical pavement structure according to the principle of combination of old cement pavement overlay structure design, and calculated that the tensile stress and shear stress in asphalt layer ,semi-flexible layer and the tensile in the old cement pavement adopting BISA3.0 statics finite element analysis model when modulus in the old road was diminishing. Use the computed result to analyses the influence of old road damage condition the influence of pavement structure.

  4. Structure determination of a multilayer with an island-like overlayer using hard x-ray photoelectron spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Isomura, N., E-mail: isomura@mosk.tytlabs.co.jp; Kataoka, K.; Horibuchi, K.; Dohmae, K.; Kitazumi, K.; Takahashi, N.; Kimoto, Y. [Toyota Central R& D Laboratories, Inc., 41-1 Yokomichi, Nagakute, Aichi 480-1192 (Japan); Oji, H.; Cui, Y.-T.; Son, J.-Y. [Japan Synchrotron Radiation Research Institute (JASRI), 1-1-1 Kouto, Sayo, Hyogo 679-5198 (Japan)

    2016-07-27

    We use hard X-ray photoelectron spectroscopy (HAXPES) to obtain the surface structure of a multilayer Au/SiO{sub 2}/Si substrate sample with an island-like overlayer. Photoelectron intensities are measured as a function of incident photon energy (PE) and take-off angle (TOA, measured from the sample surface). The Au layer coverage and Au and SiO{sub 2} layer thicknesses are obtained by the PE dependence, and are used for the following TOA analysis. The Au island lateral width in the cross section is obtained by the TOA dependence, including information about surface roughness, in consideration of the island shadowing at small TOAs. In both cases, curve-fitting analysis is conducted. The surface structure, which consists of layer thicknesses, overlayer coverage and island width, is determined nondestructively by a combination of PE and TOA dependent HAXPES measurements.

  5. Theoretical simulations of atomic and polyatomic bombardment of an organic overlayer on a metallic substrate

    CERN Document Server

    Krantzman, K D; Delcorte, A; Garrison, B J

    2003-01-01

    Our previous molecular dynamics simulations on initial test systems have laid the foundation for understanding some of the effects of polyatomic bombardment. In this paper, we describe simulations of the bombardment of a more realistic model system, an overlayer of sec-butyl-terminated polystyrene tetramers on a Ag left brace 1 1 1 right brace substrate. We have used this model system to study the bombardment with Xe and SF sub 5 projectiles at kinetic energies ranging from 0.50 to 5.0 keV. SF sub 5 sputters more molecules than Xe, but a higher percentage of these are damaged rather than ejected intact when the bombarding energy is greater than 0.50 keV. Therefore, at energies comparable to experimental values, the efficiency, measured as the yield-to-damage ratio, is greater with Xe than SF sub 5. Stable and intact molecules are generally produced by upward moving substrate atoms, while fragments are produced by the upward and lateral motion of reflected projectile atoms and fragments from the target molecul...

  6. 3-D augmented reality for MRI-guided surgery using integral videography autostereoscopic image overlay.

    Science.gov (United States)

    Liao, Hongen; Inomata, Takashi; Sakuma, Ichiro; Dohi, Takeyoshi

    2010-06-01

    A 3-D augmented reality navigation system using autostereoscopic images was developed for MRI-guided surgery. The 3-D images are created by employing an animated autostereoscopic image, integral videography (IV), which provides geometrically accurate 3-D spatial images and reproduces motion parallax without using any supplementary eyeglasses or tracking devices. The spatially projected 3-D images are superimposed onto the surgical area and viewed via a half-silvered mirror. A fast and accurate spatial image registration method was developed for intraoperative i.v. image-guided therapy. Preliminary experiments showed that the total system error in patient-to-image registration was 0.90 +/- 0.21 mm, and the procedure time for guiding a needle toward a target was shortened by 75%. An animal experiment was also conducted to evaluate the performance of the system. The feasibility studies showed that augmented reality of the image overlay system could increase the surgical instrument placement accuracy and reduce the procedure time as a result of intuitive 3-D viewing.

  7. Visual Overlay on OpenStreetMap Data to Support Spatial Exploration of Urban Environments

    Directory of Open Access Journals (Sweden)

    Chandan Kumar

    2015-01-01

    Full Text Available Increasing volumes of spatial data about urban areas are captured and made available via volunteered geographic information (VGI sources, such as OpenStreetMap (OSM. Hence, new opportunities arise for regional exploration that can lead to improvements in the lives of citizens through spatial decision support. We believe that the VGI data of the urban environment could be used to present a constructive overview of the regional infrastructure with the advent of web technologies. Current location-based services provide general map-based information for the end users with conventional local search functionality, and hence, the presentation of the rich urban information is limited. In this work, we analyze the OSM data to classify the geo entities into consequential categories with facilities, landscape and land use distribution. We employ a visual overlay of heat map and interactive visualizations to present the regional characterization on OSM data classification. In the proposed interface, users are allowed to express a variety of spatial queries to exemplify their geographic interests. They can compare the characterization of urban areas with respect to multiple spatial dimensions of interest and can search for the most suitable region. The search experience is further enhanced via efficient optimization and interaction methods to support the decision making of end users. We report the end user acceptability and efficiency of the proposed system via usability studies and performance analysis comparison.

  8. Interaction of epitaxial silicene with overlayers formed by exposure to Al atoms and O2 molecules.

    Science.gov (United States)

    Friedlein, R; Van Bui, H; Wiggers, F B; Yamada-Takamura, Y; Kovalgin, A Y; de Jong, M P

    2014-05-28

    As silicene is not chemically inert, the study and exploitation of its electronic properties outside of ultrahigh vacuum environments require the use of insulating capping layers. In order to understand if aluminum oxide might be a suitable encapsulation material, we used high-resolution synchrotron photoelectron spectroscopy to study the interactions of Al atoms and O2 molecules, as well as the combination of both, with epitaxial silicene on thin ZrB2(0001) films grown on Si(111). The deposition of Al atoms onto silicene, up to the coverage of about 0.4 Al per Si atoms, has little effect on the chemical state of the Si atoms. The silicene-terminated surface is also hardly affected by exposure to O2 gas, up to a dose of 4500 L. In contrast, when Al-covered silicene is exposed to the same dose, a large fraction of the Si atoms becomes oxidized. This is attributed to dissociative chemisorption of O2 molecules by Al atoms at the surface, producing reactive atomic oxygen species that cause the oxidation. It is concluded that aluminum oxide overlayers prepared in this fashion are not suitable for encapsulation since they do not prevent but actually enhance the degradation of silicene.

  9. Overlay of neuromagnetic current-density images and morphological MR images

    Science.gov (United States)

    Fuchs, Manfred; Wischmann, Hans-Aloys; Doessel, Olaf

    1992-09-01

    Neuromagnetic imaging is a relatively new diagnostic tool for examination of electric activities in the nervous system. It is based on the noninvasive detection of extremely weak magnetic fields around the human body with superconducting quantum interference device (SQUID) detectors. `Equivalent current dipoles' and linear estimation reconstructions of current distributions both with spherical volume conductor models are used to localize the neural activity. For practical use in medical diagnosis a combination of the abstract neuromagnetic images with magnetic resonance (MR)- or computer tomography (CT)-images is required in order to match the functional activity with anatomy and morphology. The neuromagnetic images can be overlayed onto three-dimensional morphological images with spatially arbitrarily selectable slices. The matching of both imaging modalities is discussed. Based on the detection of auditory evoked magnetic fields, neuromagnetic images are reconstructed with linear estimation theory algorithms. The MR images are used as a-priori information of the volume conductor geometry and they allow an attachment of functional and morphological properties.

  10. Optical resonance analysis of reflected long period fiber gratings with metal film overlay

    Science.gov (United States)

    Zhang, Guiju; Cao, Bing; Wang, Chinua; Zhao, Minfu

    2008-11-01

    We present the experimental results of a novel single-ended reflecting surface plasma resonance (SPR) based long period fiber grating (LPFG) sensor. A long period fiber grating sensing device is properly designed and fabricated with a pulsed CO2 laser writing system. Different nm-thick thin metal films are deposited on the fiber cladding and the fiber end facet for the excitation of surface plasma waves (SPWs) and the reflection of the transmission spectrum of the LPFG with doubled interaction between metal-dielectric interfaces of the fiber to enhance the SPW of the all-fiber SPR-LPFG sensing system. Different thin metal films with different thicknesses are investigated. The effect of the excited SPW transmission along the fiber cladding-metal interface with silver and aluminum films is observed. It is found that different thicknesses of the metal overlay show different resonant behaviors in terms of resonance peak situation, bandwidth and energy loss. Within a certain range, thinner metal film shows narrower bandwidth and deeper peak loss.

  11. Overlay Cognitive Radios With Channel-Aware Adaptive Link Selection and Buffer-Aided Relaying

    KAUST Repository

    Shaqfeh, Mohammad

    2015-08-01

    The aim of this work is to maximize the long-term average achievable rate region of a primary and a secondary source-destination pairs operating in an overlay setup over block-fading channels. To achieve this objective, we propose an opportunistic strategy to grant channel access to the primary and secondary sources based on the channel conditions in order to exploit the available multiple-link diversity gains in the system. The secondary source has causal knowledge of the primary messages and it acts as a relay of the primary source in return for getting access to the channel. To maximize the gains of relaying, the relay and destination are equipped with buffers to enable the use of channel-aware adaptive link selection. We propose and optimize different link selection policies and characterize their expected achievable rates. Also, we provide several numerical results to demonstrate the evident mutual benefits of buffer-aided cooperation and adaptive link selection to the primary and the secondary source-destination pairs. © 1972-2012 IEEE.

  12. Ultra-Deep Bone Diagnostics with Fat-Skin Overlayers Using New Pulsed Photothermal Radar

    Science.gov (United States)

    Sreekumar, K.; Mandelis, A.

    2013-09-01

    The constraints imposed by the laser safety (maximum permissible exposure) ceiling on pump laser energy and the strong attenuation of thermal-wave signals in tissues significantly limit the photothermally active depth in most biological specimens to a level which is normally insufficient for practical applications (a few mm below the skin surface). A theoretical approach for improvement of the signal-to-noise ratio (SNR), minimizing the static (dc) component of the photothermal (PT) signal and making use of the PT radiometric nonlinearity has been introduced. At low frequencies fixed-pulse-width chirps of large peak power were found to be superior to all other equal energy modalities, with an SNR improvement by up to two orders of magnitude. Compared to radar peak delay and amplitude, the long-delayed radar output amplitude is found to be more sensitive to subsurface conditions. Two-dimensional spatial plots of this parameter depicting the back-surface conditions of bones with and without fat tissue overlayers are presented. Pulsed-chirp radar thermography has been demonstrated to monitor the degree of demineralization in goat rib bone with a substantial SNR and spatial resolution that is not practicable with harmonic radars of the same energy density.

  13. Synchrotron radiation photoemission study of metal overlayers on hydrogenated amorphous silicon at room temperature

    Energy Technology Data Exchange (ETDEWEB)

    Pi, J.

    1990-09-21

    In this dissertation, metals deposited on a hydrogenated amorphous silicon (a-Si:H) film at room temperature are studied. The purpose of this work is mainly understanding the electronic properties of the interface, using high-resolution synchrotron radiation photoemission techniques as a probe. Atomic hydrogen plays an important role in passivating dangling bonds of a-Si:H films, thus reducing the gap-state distribution. In addition, singly bonded hydrogen also reduces states at the top of the valence band which are now replaced by deeper Si-H bonding states. The interface is formed by evaporating metal on an a-Si:H film in successive accumulations at room temperature. Au, Ag, and Cr were chosen as the deposited metals. Undoped films were used as substrates. Since some unique features can be found in a-Si:H, such as surface enrichment of hydrogen diffused from the bulk and instability of the free surface, we do not expect the metals/a-Si:H interface to behave exactly as its crystalline counterpart. Metal deposits, at low coverages, are found to gather preferentially around regions deficient in hydrogen. As the thickness is increased, some Si atoms in those regions are likely to leave their sites to intermix with metal overlayers like Au and Cr. 129 refs., 30 figs.

  14. Wafer-based aberration metrology for lithographic systems using overlay measurements on targets imaged from phase-shift gratings.

    Science.gov (United States)

    van Haver, Sven; Coene, Wim M J; D'havé, Koen; Geypen, Niels; van Adrichem, Paul; de Winter, Laurens; Janssen, Augustus J E M; Cheng, Shaunee

    2014-04-20

    In this paper, a new methodology is presented to derive the aberration state of a lithographic projection system from wafer metrology data. For this purpose, new types of phase-shift gratings (PSGs) are introduced, with special features that give rise to a simple linear relation between the PSG image displacement and the phase aberration function of the imaging system. By using the PSGs as the top grating in a diffraction-based overlay stack, their displacement can be measured as an overlay error using a standard wafer metrology tool. In this way, the overlay error can be used as a measurand based on which the phase aberration function in the exit pupil of the lithographic system can be reconstructed. In practice, the overlay error is measured for a set of different PSG targets, after which this information serves as input to a least-squares optimization problem that, upon solving, provides estimates for the Zernike coefficients describing the aberration state of the lithographic system. In addition to a detailed method description, this paper also deals with the additional complications that arise when the method is implemented experimentally and this leads to a number of model refinements and a required calibration step. Finally, the overall performance of the method is assessed through a number of experiments in which the aberration state of the lithographic system is intentionally detuned and subsequently estimated by the new method. These experiments show a remarkably good agreement, with an error smaller than 5  mλ, among the requested aberrations, the aberrations measured by the on-tool aberration sensor, and the results of the new wafer-based method.

  15. Distributed fiber optic sensor-enhanced detection and prediction of shrinkage-induced delamination of ultra-high-performance concrete overlay

    Science.gov (United States)

    Bao, Yi; Valipour, Mahdi; Meng, Weina; Khayat, Kamal H.; Chen, Genda

    2017-08-01

    This study develops a delamination detection system for smart ultra-high-performance concrete (UHPC) overlays using a fully distributed fiber optic sensor. Three 450 mm (length) × 200 mm (width) × 25 mm (thickness) UHPC overlays were cast over an existing 200 mm thick concrete substrate. The initiation and propagation of delamination due to early-age shrinkage of the UHPC overlay were detected as sudden increases and their extension in spatial distribution of shrinkage-induced strains measured from the sensor based on pulse pre-pump Brillouin optical time domain analysis. The distributed sensor is demonstrated effective in detecting delamination openings from microns to hundreds of microns. A three-dimensional finite element model with experimental material properties is proposed to understand the complete delamination process measured from the distributed sensor. The model is validated using the distributed sensor data. The finite element model with cohesive elements for the overlay-substrate interface can predict the complete delamination process.

  16. TEM Microstructure and Chemical Composition of Transition Zone Between Steel Tube and An Inconel 625 Weld Overlay Coating Produced by CMT Method

    National Research Council Canada - National Science Library

    M. Rozmus-Górnikowska; M. Blicharski

    2017-01-01

    The aim of this work was to investigate the microstructure and chemical composition of the transition zone between 16Mo3 steel and Inconel 625 weld overlay coating produced by the Cold Metal Transfer (CMT) method...

  17. Assessment of Weld Overlays for Mitigating Primary Water Stress Corrosion Cracking at Nickel Alloy Butt Welds in Piping Systems Approved for Leak-Before-Break

    Energy Technology Data Exchange (ETDEWEB)

    Sullivan, Edward J.; Anderson, Michael T.

    2012-08-01

    This TLR provides an assessment of weld overlays as a mitigation strategy for PWSCC, and includes an assessment of the WOL-related inspection requirements of Code Case N-770-1, as conditioned in §50.55a.

  18. Thermo-Mechanical Analysis of a Single-Pass Weld Overlay and Girth Welding in Lined Pipe

    Science.gov (United States)

    Obeid, Obeid; Alfano, Giulio; Bahai, Hamid

    2017-08-01

    The paper presents a nonlinear heat-transfer and mechanical finite-element (FE) analyses of a two-pass welding process of two segments of lined pipe made of a SUS304 stainless steel liner and a C-Mn steel pipe. The two passes consist of the single-pass overlay welding (inner lap weld) of the liner with the C-Mn steel pipe for each segment and the single-pass girth welding (outer butt weld) of the two segments. A distributed power density of the moving welding torch and a nonlinear heat-transfer coefficient accounting for both radiation and convection have been used in the analysis and implemented in user subroutines for the FE code ABAQUS. The modeling procedure has been validated against previously published experimental results for stainless steel and carbon steel welding separately. The model has been then used to determine the isotherms induced by the weld overlay and the girth welding and to clarify their influence on the transient temperature field and residual stress in the lined pipe. Furthermore, the influence of the cooling time between weld overlay and girth welding and of the welding speed have been examined thermally and mechanically as they are key factors that can affect the quality of lined pipe welding.

  19. Energy-Efficient Cluster-Based Service Discovery in Wireless Sensor Networks

    NARCIS (Netherlands)

    Marin Perianu, Raluca; Scholten, Johan; Havinga, Paul J.M.; Hartel, Pieter H.

    2006-01-01

    We propose an energy-efficient service discovery protocol for wireless sensor networks. Our solution exploits a cluster overlay, where the clusterhead nodes form a distributed service registry. A service lookup results in visiting only the clusterhead nodes. We aim for minimizing the communication

  20. Delay-Tolerant Networking for Space Flight Operations: Design and Development

    Science.gov (United States)

    Burleigh, Scott

    2008-01-01

    Large-scale future space exploration will offer complex communication challenges that may be best addressed by establishing a network infrastructure. The Internet protocols are not well suited for operation of a network over interplanetary distances; a Delay-Tolerant Networking (DTN) architecture has been proposed instead. DTN is now a rapidly growing research field, but most implementations are mainly aimed at supporting applications of DTN technology to terrestrial networking problems. Those implementations are not necessarily suitable for deployment in an interplanetary network. Interplanetary Overlay Network (ION) is an implementation of the DTN architecture that is specifically designed for use in resource-constrained embedded systems, such as interplanetary robotic spacecraft.

  1. Combining Unsupervised Anomaly Detection and Neural Networks for Driver Identification

    Directory of Open Access Journals (Sweden)

    Thitaree Tanprasert

    2017-01-01

    Full Text Available This paper proposes an algorithm for real-time driver identification using the combination of unsupervised anomaly detection and neural networks. The proposed algorithm uses nonphysiological signals as input, namely, driving behavior signals from inertial sensors (e.g., accelerometers and geolocation signals from GPS sensors. First anomaly detection is performed to assess if the current driver is whom he/she claims to be. If an anomaly is detected, the algorithm proceeds to find relevant features in the input signals and use neural networks to identify drivers. To assess the proposed algorithm, real-world data are collected from ten drivers who drive different vehicles on several routes in real-world traffic conditions. Driver identification is performed on each of the seven-second-long driving behavior signals and geolocation signals in a streaming manner. It is shown that the proposed algorithm can achieve relatively high accuracy and identify drivers within 13 seconds. The proposed algorithm also outperforms the previously proposed driver identification algorithms. Furthermore, to demonstrate how the proposed algorithm can be deployed in real-world applications, results from real-world data associated with each operation of the proposed algorithm are shown step-by-step.

  2. A path-following driver-vehicle model with neuromuscular dynamics, including measured and simulated responses to a step in steering angle overlay

    Science.gov (United States)

    Cole, David J.

    2012-04-01

    An existing driver-vehicle model with neuromuscular dynamics is improved in the areas of cognitive delay, intrinsic muscle dynamics and alpha-gamma co-activation. The model is used to investigate the influence of steering torque feedback and neuromuscular dynamics on the vehicle response to lateral force disturbances. When steering torque feedback is present, it is found that the longitudinal position of the lateral disturbance has a significant influence on whether the driver's reflex response reinforces or attenuates the effect of the disturbance. The response to angle and torque overlay inputs to the steering system is also investigated. The presence of the steering torque feedback reduced the disturbing effect of torque overlay and angle overlay inputs. Reflex action reduced the disturbing effect of a torque overlay input, but increased the disturbing effect of an angle overlay input. Experiments on a driving simulator showed that measured handwheel angle response to an angle overlay input was consistent with the response predicted by the model with reflex action. However, there was significant intra- and inter-subject variability. The results highlight the significance of a driver's neuromuscular dynamics in determining the vehicle response to disturbances.

  3. Novel WLL Architecture Based on Color Pixel Multiple Access Implemented on a Terrestrial Video Network as the Overlay

    DEFF Research Database (Denmark)

    Sanyal, Rajarshi; Cianca, Ernestina; Prasad, Ramjee

    2013-01-01

    Light waves of different wavelengths and frequencies manifest in various colors. Color can be formulated electronically by video processing technologies for the purpose of multimedia, image processing and entertainment. Optoelectronic devices like DWDM use optical signals of various wave lengths...

  4. Giant positive magneto-crystalline anisotropy in ferromagnetic Mn/W(001) overlayer

    Energy Technology Data Exchange (ETDEWEB)

    Ondracek, Martin; Shick, Alexander; Maca, Frantisek; Jungwirth, Tomas [Institute of Physics ASCR, Prague (Czech Republic)

    2008-07-01

    Proposal of the ferromagnetic (FM) ground state for Mn monatomic overlayer on W(001) is reported recently by Ferriani et al. on the basis of first-principles calculations. We study the magneto-crystalline anisotropy (MAE), spin (M{sub S}) and orbital (M{sub L}) magnetic moments, and tunneling anisotropic magneto-resistance (TAMR) of FM-Mn/W(001). The anisotropic properties of Mn/W(001) were investigated making use of the relativistic version of the FP-LAPW method, in which SO coupling is included in a self-consistent second-variational procedure. The magnetic force theorem was used to evaluate the MAE and the DOS anisotropy. For the Mn atom, out-of-plane M{sub S}=3.18 {mu}{sub B} and M{sub L}=0.09 {mu}{sub B} are calculated. There is a strong induced W-interface M{sub S}=-0.34 {mu}{sub B} and M{sub L}=-0.06 {mu}{sub B}. The spin and orbital polarizations of W are quickly decaying away from the interface, showing slow oscillations. When the magnetization is rotated in-plane, there is no anisotropy in M{sub S}, and a pronounced reduction of in-plane M{sub L}. Accordingly, the very big positive MAE of 5.6 meV per Mn-atom is calculated, which is shown to originate from the W contribution. In addition, the TAMR is estimated from the densities of states anisotropy.

  5. Groundwater vulnerability assessment: from overlay methods to statistical methods in the Lombardy Plain area

    Directory of Open Access Journals (Sweden)

    Stefania Stevenazzi

    2017-06-01

    Full Text Available Groundwater is among the most important freshwater resources. Worldwide, aquifers are experiencing an increasing threat of pollution from urbanization, industrial development, agricultural activities and mining enterprise. Thus, practical actions, strategies and solutions to protect groundwater from these anthropogenic sources are widely required. The most efficient tool, which helps supporting land use planning, while protecting groundwater from contamination, is represented by groundwater vulnerability assessment. Over the years, several methods assessing groundwater vulnerability have been developed: overlay and index methods, statistical and process-based methods. All methods are means to synthesize complex hydrogeological information into a unique document, which is a groundwater vulnerability map, useable by planners, decision and policy makers, geoscientists and the public. Although it is not possible to identify an approach which could be the best one for all situations, the final product should always be scientific defensible, meaningful and reliable. Nevertheless, various methods may produce very different results at any given site. Thus, reasons for similarities and differences need to be deeply investigated. This study demonstrates the reliability and flexibility of a spatial statistical method to assess groundwater vulnerability to contamination at a regional scale. The Lombardy Plain case study is particularly interesting for its long history of groundwater monitoring (quality and quantity, availability of hydrogeological data, and combined presence of various anthropogenic sources of contamination. Recent updates of the regional water protection plan have raised the necessity of realizing more flexible, reliable and accurate groundwater vulnerability maps. A comparison of groundwater vulnerability maps obtained through different approaches and developed in a time span of several years has demonstrated the relevance of the

  6. Evaluation of a portable image overlay projector for the visualisation of surgical navigation data: phantom studies.

    Science.gov (United States)

    Gavaghan, K; Oliveira-Santos, T; Peterhans, M; Reyes, M; Kim, H; Anderegg, S; Weber, S

    2012-07-01

    Presenting visual feedback for image-guided surgery on a monitor requires the surgeon to perform time-consuming comparisons and diversion of sight and attention away from the patient. Deficiencies in previously developed augmented reality systems for image-guided surgery have, however, prevented the general acceptance of any one technique as a viable alternative to monitor displays. This work presents an evaluation of the feasibility and versatility of a novel augmented reality approach for the visualisation of surgical planning and navigation data. The approach, which utilises a portable image overlay device, was evaluated during integration into existing surgical navigation systems and during application within simulated navigated surgery scenarios. A range of anatomical models, surgical planning data and guidance information taken from liver surgery, cranio-maxillofacial surgery, orthopaedic surgery and biopsy were displayed on patient-specific phantoms, directly on to the patient's skin and on to cadaver tissue. The feasibility of employing the proposed augmented reality visualisation approach in each of the four tested clinical applications was qualitatively assessed for usability, visibility, workspace, line of sight and obtrusiveness. The visualisation approach was found to assist in spatial understanding and reduced the need for sight diversion throughout the simulated surgical procedures. The approach enabled structures to be identified and targeted quickly and intuitively. All validated augmented reality scenes were easily visible and were implemented with minimal overhead. The device showed sufficient workspace for each of the presented applications, and the approach was minimally intrusiveness to the surgical scene. The presented visualisation approach proved to be versatile and applicable to a range of image-guided surgery applications, overcoming many of the deficiencies of previously described AR approaches. The approach presents an initial step

  7. Enabling multimode wireless access networks using remote radio heads

    DEFF Research Database (Denmark)

    Kardaras, Georgios; Soler, José; Dittmann, Lars

    2012-01-01

    The deployment of 4G networks is spreading rapidly providing mobile broadband services to the public. 4G technologies are designed to overlay existing 3G networks enabling reusability of several network components. In this way, the coexistence of 3G/4G standards is facilitated. This paper describes...... and management plane. Switching between wireless standards becomes easily feasible through firmware upgrading. Finally, real-time configuration of radio functionalities, such as transmit power, receiver gain, carrier frequency, channel bandwidth and others result in a modular software defined radio platform....... © 2012 ICST Institute for Computer Science, Social Informatics and Telecommunications Engineering....

  8. Network Monitoring and Diagnosis Based on Available Bandwidth Measurement

    Science.gov (United States)

    2006-05-01

    encouragements helped me pass those tough early days in the US. I would also like to thank my officemates Julio Lopez and Rajesh Balan, both system experts. With...tradeoffs of structured overlays in a dynamic non-transitive network. In MIT 6.829 Fall 2003 class project, December 2003. [52] Ramesh Govindan and Vern ...using packet quartets. In ACM SIGCOMM Internet Measurement Workshop 2002, 2002. [92] Vern Paxson. Measurements and Analysis of End-to-End Internet

  9. Incommensurate Moiré overlayer with strong local binding: CoO(111) bilayer on Ir(100)

    Science.gov (United States)

    Tröppner, C.; Schmitt, T.; Reuschl, M.; Hammer, L.; Schneider, M. A.; Mittendorfer, F.; Redinger, J.; Podloucky, R.; Weinert, M.

    2012-12-01

    Incommensurate relaxed overlayer Moiré structures are often interpreted as systems with weak lateral variations of the binding potential and thus no structural modulations in the overlayer material. We discuss here the example of a CoO(111) bilayer on Ir(100), which is a relaxed overlayer with strong structural response to the lateral modulation of interface properties but nevertheless is incommensurate. By means of density functional theory (DFT) calculations, we quantitatively reproduce all the structural parameters of the CoO(111) bilayer on Ir(100) as proposed by a recent low-energy electron diffraction analysis [Ebensperger , Phys. Rev. BPRBMDO1098-012110.1103/PhysRevB.81.235405 81, 235405 (2010)]. The calculations predict energetic degeneracies with respect to registry shifts of the CoO(111) film along [011¯]. Large-scale, low-temperature scanning tunneling microscopy topographies reveal that the true structure of the film is incommensurate in this direction, exhibiting a one-dimensional Moiré pattern with a period of about 9.4 aIr. From DFT calculations for limiting (periodic) models, we can sample the potential landscape of the cobalt and oxygen atoms in the Moiré structure across the Ir(100) unit cell. We find that despite the non-commensurability of the film, the binding to the substrate is site specific with strong attraction and repulsion points for both cobalt and oxygen atoms, leading to severe local distortions in the film. The lateral modulation of the structural elements within the oxide film can be understood as a combination of the lateral variation in the Co-Ir binding potential and additional O-Ir binding.

  10. Framework for Development of Advanced Telecommunication Services in Current and Future Converged Networks

    DEFF Research Database (Denmark)

    Soler-Lucas, José

    2006-01-01

    This thesis presents different experiences related to architectures and mechanisms for deployment of telephony services, understood as especial features complementing the basic voice service. The context for these experiences is the transition of telecommunication (telephony) networks from circuit...... been designed, implemented and tested as part of this demonstration. Performance characterization of different service implementations is also provided. Finally, a data model for an overlay network to existing telecommunication (telephony) infrastructures, allowing operational convergence is described....

  11. Electronic and structural characterizations of unreconstructed {l_brace}0001{r_brace} surfaces and the growth of graphene overlayers

    Energy Technology Data Exchange (ETDEWEB)

    Emtsev, Konstantin

    2009-06-03

    The present work is focused on the characterization of the clean unreconstructed SiC{l_brace}0001{r_brace} surfaces and the growth of graphene overlayers thereon. Electronic properties of SiC surfaces and their interfaces with graphene and few layer graphene films were investigated by means of angle resolved photoelectron spectroscopy, X-ray photoelectron spectroscopy and low energy electron diffraction. Structural characterizations of the epitaxial graphene films grown on SiC were carried out by atomic force microscopy and low energy electron microscopy. Supplementary data was obtained by scanning tunneling microscopy. (orig.)

  12. Laser-induced ferroelectric domain engineering in LiNbO3 crystals using an amorphous silicon overlayer

    Science.gov (United States)

    Zisis, G.; Martinez-Jimenez, G.; Franz, Y.; Healy, N.; Masaud, T. M.; Chong, H. M. H.; Soergel, E.; Peacock, A. C.; Mailis, S.

    2017-08-01

    We report laser-induced poling inhibition and direct poling in lithium niobate crystals (LiNbO3), covered with an amorphous silicon (a-Si) light-absorbing layer, using a visible (488 nm) continuous wave laser source. Our results show that the use of the a-Si overlayer produces deeper poling inhibited domains with minimum surface damage, as compared to previously reported UV laser writing experiments on uncoated crystals, thus increasing the applicability of this method in the production of ferroelectric domain engineered structures for nonlinear optical applications. The characteristics of the poling inhibited domains were investigated using differential etching and piezoresponse force microscopy.

  13. Gas selectivity control in Co3O4 sensor via concurrent tuning of gas reforming and gas filtering using nano-scale hetero-overlayer of catalytic oxides.

    Science.gov (United States)

    Jeong, Hyun-Mook; Jeong, Seong-Yong; Kim, Jae-Hyeok; Kim, Bo-Young; Kim, Jun-Sik; Abdel-Hady, Faissal; Wazzan, Abdulaziz A; Al-Turaif, Hamad Ali; Jang, Ho Won; Lee, Jong-Heun

    2017-11-07

    Co3O4 sensors with a nanoscale TiO2 or SnO2 catalytic overlayer were prepared by screen printing of Co3O4 yolk-shell spheres and subsequent e-beam evaporation of TiO2 and SnO2. The Co3O4 sensors with 5 nm thick TiO2 and SnO2 overlayers showed high responses (resistance ratios) to 5 ppm xylene (14.5 and 28.8) and toluene (11.7 and 16.2) at 250°C with negligible responses to interference gases such as ethanol, HCHO, CO, and benzene. In contrast, the pure Co3O4 sensor did not show remarkable selectivity toward any specific gas. The response and selectivity to methylbenzenes and ethanol could be systematically controlled by selecting the catalytic overlayer material, varying the overlayer thickness, and tuning the sensing temperature. The significant enhancement of the selectivity for xylene and toluene was attributed to the reforming of less reactive methylbenzenes into more reactive and smaller species and oxidative filtering of other interference gases, including ubiquitous ethanol. The concurrent control of the gas reforming and oxidative filtering processes using a nano-scale overlayer of catalytic oxides provides a new, general, and powerful tool for designing highly selective and sensitive oxide semiconductor gas sensors.

  14. NON LINEAR OPTIMIZATION APPLIED TO ANGLE-OF-ARRIVAL SATELLITE BASED GEO-LOCALIZATION FOR BIASED AND TIME-DRIFTING SENSORS

    Directory of Open Access Journals (Sweden)

    D. Levy

    2016-06-01

    Full Text Available Multiple sensors are used in a variety of geolocation systems. Many use Time Difference of Arrival (TDOA or Received Signal Strength (RSS measurements to estimate the most likely location of a signal. When an object does not emit an RF signal, Angle of Arrival (AOA measurements using optical or infrared frequencies become more feasible than TDOA or RSS measurements. AOA measurements can be created from any sensor platform with any sort of optical sensor, location and attitude knowledge to track passive objects. Previous work has created a non-linear optimization (NLO method for calculating the most likely estimate from AOA measurements. Two new modifications to the NLO algorithm are created and shown to correct AOA measurement errors by estimating the inherent bias and time-drift in the Inertial Measurement Unit (IMU of the AOA sensing platform. One method corrects the sensor bias in post processing while treating the NLO method as a module. The other method directly corrects the sensor bias within the NLO algorithm by incorporating the bias parameters as a state vector in the estimation process. These two methods are analyzed using various Monte-Carlo simulations to check the general performance of the two modifications in comparison to the original NLO algorithm.

  15. [A simple and reliable technique for the treatment of rhinoliquorrhoea from small defects: Free nasal mucosa overlay graft].

    Science.gov (United States)

    Armengot, Miguel; Gómez-Gómez, M José; García-Lliberós, Ainhoa

    2013-01-01

    Cerebrospinal fluid leaks to the sinonasal cavities (rhinoliquorrhoea) represent a process with diagnostic and therapeutic difficulties. The endoscopic transnasal approach is the method of choice, but with many possible variants. The purpose of this paper was to make a critical review of our diagnostic and therapeutic protocol used for 11years. We operated on 31patients. The diagnosis was based on the biochemical analysis of rhinorrhoea, CT and MRI. endoscopic nasal surgery after preoperative intrathecal injection of 5% fluorescein (2cc). Closure was performed using a free overlay graft from middle turbinate mucosa. Two patients had meningitis as the first sign. All patients were diagnosed by biochemical analysis of rhinorrhoea. CT and MRI gave clear evidence of the leakage location. The skull base defect was always less than 1cm. Fluorescein allowed clear visualisation of the fistulous area without other instruments and produced no side effects. One patient had a postoperative frontal abscess, which evolved favourably. All fistulas were closed and there was only one recurrence at 10years, which debuted as pneumococcal meningitis. Our surgical protocol, based on the use of intrathecal fluorescein and free grafting of middle turbinate mucosa overlay onto the fistulous area, achieves successful long-term results in the management of rhinoliquorrhoea secondary to small skull base defects. Copyright © 2012 Sociedad Española de Neurocirugía. Published by Elsevier España. All rights reserved.

  16. Augmented reality navigation with automatic marker-free image registration using 3-D image overlay for dental surgery.

    Science.gov (United States)

    Wang, Junchen; Suenaga, Hideyuki; Hoshi, Kazuto; Yang, Liangjing; Kobayashi, Etsuko; Sakuma, Ichiro; Liao, Hongen

    2014-04-01

    Computer-assisted oral and maxillofacial surgery (OMS) has been rapidly evolving since the last decade. State-of-the-art surgical navigation in OMS still suffers from bulky tracking sensors, troublesome image registration procedures, patient movement, loss of depth perception in visual guidance, and low navigation accuracy. We present an augmented reality navigation system with automatic marker-free image registration using 3-D image overlay and stereo tracking for dental surgery. A customized stereo camera is designed to track both the patient and instrument. Image registration is performed by patient tracking and real-time 3-D contour matching, without requiring any fiducial and reference markers. Real-time autostereoscopic 3-D imaging is implemented with the help of a consumer-level graphics processing unit. The resulting 3-D image of the patient's anatomy is overlaid on the surgical site by a half-silvered mirror using image registration and IP-camera registration to guide the surgeon by exposing hidden critical structures. The 3-D image of the surgical instrument is also overlaid over the real one for an augmented display. The 3-D images present both stereo and motion parallax from which depth perception can be obtained. Experiments were performed to evaluate various aspects of the system; the overall image overlay error of the proposed system was 0.71 mm.

  17. Combined Excimer Laser Photoablation and Amniotic Membrane Overlay for Relief of Symptomatic Discomfort in Gelatinous Drop-like Corneal Dystrophy.

    Science.gov (United States)

    Alex, Anne F; Eter, Nicole; Uhlig, Constantin E

    2015-10-01

    To describe the efficacy of combined excimer laser photoablation and amniotic overlay membrane in the relief of symptomatic discomfort in a 17-year-old patient who had gelatinous drop-like corneal dystrophy. The best-corrected visual acuity (BCVA) was measured with Snellen letters. Slit-lamp examination of the ocular surface and anterior chamber was performed at baseline. Results were photodocumented. Excimer laser photoablation was performed and subsequently 2 amniotic membranes were transconjunctivally fixated with 10.0 nylon sutures. Investigations and documentation were performed at baseline, every 2 months in the first year, and then every 6 months. The duration of follow-up was 22 months. At baseline, the BCVA was 20/70 in the right eye and 20/200 in the left eye. The patient reported distinct photophobia. Slit-lamp examination was difficult because of blepharospasm. Although gelatinous drops developed again and the BCVA decreased to 2/200, the patient reported significant relief after both microsurgical treatments and remained comfortable at 20 and 22 months. Excimer laser photocoagulation combined with amniotic membrane overlay does not stop the development of gelatinous drop-like corneal dystrophy but may improve subjective comfort. Such treatment does not hinder subsequent lamellar or penetrating grafts and is helpful in providing the necessary time for preparation of matched keratoplasties.

  18. An Investigation of GIS Overlay and PCA Techniques for Urban Environmental Quality Assessment: A Case Study in Toronto, Ontario, Canada

    Directory of Open Access Journals (Sweden)

    Kamil Faisal

    2017-03-01

    Full Text Available The United Nations estimates that the global population is going to be double in the coming 40 years, which may cause a negative impact on the environment and human life. Such an impact may instigate increased water demand, overuse of power, anthropogenic noise, etc. Thus, modelling the Urban Environmental Quality (UEQ becomes indispensable for a better city planning and an efficient urban sprawl control. This study aims to investigate the ability of using remote sensing and Geographic Information System (GIS techniques to model the UEQ with a case study in the city of Toronto via deriving different environmental, urban and socio-economic parameters. Remote sensing, GIS and census data were first obtained to derive environmental, urban and socio-economic parameters. Two techniques, GIS overlay and Principal Component Analysis (PCA, were used to integrate all of these environmental, urban and socio-economic parameters. Socio-economic parameters including family income, higher education and land value were used as a reference to assess the outcomes derived from the two integration methods. The outcomes were assessed through evaluating the relationship between the extracted UEQ results and the reference layers. Preliminary findings showed that the GIS overlay represents a better precision and accuracy (71% and 65%, respectively, comparing to the PCA technique. The outcomes of the research can serve as a generic indicator to help the authority for better city planning with consideration of all possible social, environmental and urban requirements or constraints.

  19. Computer-based production of comparison overlays from 3D-scanned dental casts for bite mark analysis.

    Science.gov (United States)

    Martin-de las Heras, Stella; Valenzuela, Aurora; Ogayar, Carlos; Valverde, A Javier; Torres, Juan Carlos

    2005-01-01

    Bite mark analysis assumes the uniqueness of the dentition can be accurately recorded on skin or an object. However, biting is a dynamic procedure involving three moving systems, the maxilla, the mandible, and the victim's reaction. Moreover, bite marks can be distorted by the anatomic location of the injury or the elasticity of the skin tissue. Therefore, the same dentition can produce bite marks that exhibit variations in appearance. The complexity of this source of evidence emphasizes the need for new 3D imaging technologies in bite mark analysis. This article presents a new software package, DentalPrint (2004, University of Granada, Department of Forensic Medicine and Forensic Odontology, Granada, Spain) that generates different comparison overlays from 3D dental cast images depending on the pressure of the bite or the distortion caused by victim-biter interaction. The procedure for generating comparison overlays is entirely automatic, thus avoiding observer bias. Moreover, the software presented here makes it impossible for third parties to manipulate or alter the 3D images, making DentalPrint suitable for bite mark analyses to be used in court proceedings.

  20. Antibacterial effects of allspice, garlic, and oregano essential oils in tomato films determined by overlay and vapor-phase methods.

    Science.gov (United States)

    Du, W-X; Olsen, C W; Avena-Bustillos, R J; McHugh, T H; Levin, C E; Mandrell, R; Friedman, Mendel

    2009-09-01

    Physical properties as well as antimicrobial activities against Escherichia coli O157:H7, Salmonella enterica, and Listeria monocytogenes of allspice, garlic, and oregano essential oils (EOs) in tomato puree film-forming solutions (TPFFS) formulated into edible films at 0.5% to 3% (w/w) concentrations were investigated in this study. Antimicrobial activities were determined by 2 independent methods: overlay of the film on top of the bacteria and vapor-phase diffusion of the antimicrobial from the film to the bacteria. The results indicate that the antimicrobial activities against the 3 pathogens were in the following order: oregano oil > allspice oil > garlic oil. Listeria monocytogenes was less resistant to EO vapors, while E. coli O157:H7 was more resistant to EOs as determined by both overlay and vapor-phase diffusion tests. The presence of plant EO antimicrobials reduced the viscosity of TPFFS at the higher shear rates, but did not affect water vapor permeability of films. EOs increased elongation and darkened the color of films. The results of the present study show that the 3 plant-derived EOs can be used to prepare tomato-based antimicrobial edible films with good physical properties for food applications by both direct contact and indirectly by vapors emanating from the films.

  1. GoDisco: Selective Gossip Based Dissemination of Information in Social Community Based Overlays

    Science.gov (United States)

    Datta, Anwitaman; Sharma, Rajesh

    We propose and investigate a gossip based, social principles and behavior inspired decentralized mechanism (GoDisco) to disseminate information in online social community networks, using exclusively social links and exploiting semantic context to keep the dissemination process selective to relevant nodes. Such a designed dissemination scheme using gossiping over a egocentric social network is unique and is arguably a concept whose time has arrived, emulating word of mouth behavior and can have interesting applications like probabilistic publish/subscribe, decentralized recommendation and contextual advertisement systems, to name a few. Simulation based experiments show that despite using only local knowledge and contacts, the system has good global coverage and behavior.

  2. Colored overlays for visual perceptual deficits in children with reading disability and attention deficit/hyperactivity disorder: are they differentially effective?

    Science.gov (United States)

    Iovino, I; Fletcher, J M; Breitmeyer, B G; Foorman, B R

    1998-12-01

    The Transient Channel Deficit (TCD) model of reading disability was evaluated by examining the effects of color overlays on the reading ability of four groups of children (n = 15 each) with reading disability and comorbid conditions involving math and ADHD. These 60 children were evaluated for reading accuracy and rate on measures of word decoding and reading comprehension under three color transparency conditions (blue, red, no overlay). Results indicated that color overlays did not differentially affect the reading performance of individuals with and without reading disabilities. However, blue transparencies significantly improved reading comprehension in all groups, and reduced reading rate. These findings indicate that the TCD model may need to be reexamined. An alternative hypothesis for the observed effects, involving facilitation of attention processes, was posted.

  3. A complete methodology towards accuracy and lot-to-lot robustness in on-product overlay metrology using flexible wavelength selection

    Science.gov (United States)

    Bhattacharyya, Kaustuve; den Boef, Arie; Noot, Marc; Adam, Omer; Grzela, Grzegorz; Fuchs, Andreas; Jak, Martin; Liao, Sax; Chang, Ken; Couraudon, Vincent; Su, Eason; Tzeng, Wilson; Wang, Cathy; Fouquet, Christophe; Huang, Guo-Tsai; Chen, Kai-Hsiung; Wang, Y. C.; Cheng, Kevin; Ke, Chih-Ming; Terng, L. G.

    2017-03-01

    The optical coupling between gratings in diffraction-based overlay triggers a swing-curve1,6 like response of the target's signal contrast and overlay sensitivity through measurement wavelengths and polarizations. This means there are distinct measurement recipes (wavelength and polarization combinations) for a given target where signal contrast and overlay sensitivity are located at the optimal parts of the swing-curve that can provide accurate and robust measurements. Some of these optimal recipes can be the ideal choices of settings for production. The user has to stay away from the non-optimal recipe choices (that are located on the undesirable parts of the swing-curve) to avoid possibilities to make overlay measurement error that can be sometimes (depending on the amount of asymmetry and stack) in the order of several "nm". To accurately identify these optimum operating areas of the swing-curve during an experimental setup, one needs to have full-flexibility in wavelength and polarization choices. In this technical publication, a diffraction-based overlay (DBO) measurement tool with many choices of wavelengths and polarizations is utilized on advanced production stacks to study swing-curves. Results show that depending on the stack and the presence of asymmetry, the swing behavior can significantly vary and a solid procedure is needed to identify a recipe during setup that is robust against variations in stack and grating asymmetry. An approach is discussed on how to use this knowledge of swing-curve to identify recipe that is not only accurate at setup, but also robust over the wafer, and wafer-to-wafer. KPIs are reported in run-time to ensure the quality / accuracy of the reading (basically acting as an error bar to overlay measurement).

  4. Energy Efficient MAC for Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Pekka KOSKELA

    2010-10-01

    Full Text Available This paper considers an overlay solution for asynchronous Medium Access Control (MAC protocols in a duty-cycled wireless sensor network (WSN. The solution extends sleeping times and corrects time drift when the sampling rate is low. The sleeping time is adjusted according to the requisite data sampling rate and the delay requirements of the prevailing application. This and the time drift correction considerably reduced idle listening and thus also decreased power consumption. When the power consumption is reduced, the life of wireless sensor nodes extends.

  5. Performance Modeling for Heterogeneous Wireless Networks with Multiservice Overflow Traffic

    DEFF Research Database (Denmark)

    Huang, Qian; Ko, King-Tim; Iversen, Villy Bæk

    2009-01-01

    Performance modeling is important for the purpose of developing efficient dimensioning tools for large complicated networks. But it is difficult to achieve in heterogeneous wireless networks, where different networks have different statistical characteristics in service and traffic models....... Multiservice loss analysis based on multi-dimensional Markov chain becomes intractable in these networks due to intensive computations required. This paper focuses on performance modeling for heterogeneous wireless networks based on a hierarchical overlay infrastructure. A method based on decomposition...... of the correlated traffic is used to achieve an approximate performance modeling for multiservice in hierarchical heterogeneous wireless networks with overflow traffic. The accuracy of the approximate performance obtained by our proposed modeling is verified by simulations....

  6. New overlay measurement technique with an i-line stepper using embedded standard field image alignment marks for wafer bonding applications

    Science.gov (United States)

    Kulse, P.; Sasai, K.; Schulz, K.; Wietstruck, M.

    2017-06-01

    In the last decades the semiconductor technology has been driven by Moore's law leading to high performance CMOS technologies with feature sizes of less than 10 nm [1]. It has been pointed out that not only scaling but also the integration of novel components and technology modules into CMOS/BiCMOS technologies is becoming more attractive to realize smart and miniaturized systems [2]. Driven by new applications in the area of communication, health and automation, new components and technology modules such as BiCMOS embedded RF-MEMS, high-Q passives, Sibased microfluidics and InP-SiGe BiCMOS heterointegration have been demonstrated [3-6]. In contrast to standard VLSI processes fabricated on front side of the silicon wafer, these new technology modules require addition backside processing of the wafer; thus an accurate alignment between the front and backside of the wafer is mandatory. In previous work an advanced back to front side alignment technique and implementation into IHP's 0.25/0.13 μm high performance SiGe:C BiCMOS backside process module has been presented [7]. The developed technique enables a high resolution and accurate lithography on the backside of BiCMOS wafer for additional backside processing. In addition to the aforementioned back side process technologies, new applications like Through-Silicon Vias (TSV) for interposers and advanced substrate technologies for 3D heterogeneous integration demand not only single wafer fabrication but also processing of wafer stacks provided by temporary and permanent wafer bonding [8]. Therefore, the available overlay measurement techniques are not suitable if overlay and alignment marks are realized at the bonding interface of a wafer stack which consists of both a silicon device and a silicon carrier wafer. The former used EVG 40NT automated overlay measurement system, which use two opposite positioned microscopes inspecting simultaneous the wafer back and front side, is not capable measuring embedded overlay

  7. Developing a Web-Based Geolocated Directory of HIV Pre-Exposure Prophylaxis-Providing Clinics: The PrEP Locator Protocol and Operating Procedures.

    Science.gov (United States)

    Siegler, Aaron J; Wirtz, Susan; Weber, Shannon; Sullivan, Patrick S

    2017-09-06

    Human immunodeficiency virus (HIV) pre-exposure prophylaxis (PrEP) is highly effective in preventing HIV transmission, yet patients interested in learning more about PrEP or in getting a PrEP prescription may not be able to find local medical providers willing to prescribe PrEP. We sought to create a national database of PrEP-providing clinics to allow for patients to have access to a unified, vetted source of PrEP providers in an easily accessible database. To develop the protocol and operating procedures for the PrEP Locator, we conducted a series of 7 key informant interviews with experts who had organized PrEP or other HIV service directories. We convened an external advisory committee and a collaborators board to gain expert and community-situated perspectives. At its public release in September 2016, the database included 1,272 PrEP-providing clinics, including clinics in all 50 states and in Puerto Rico. Web searches, referrals, and outreach to state health departments identified 58 unique lists of PrEP-providing clinics, with 33 from state health departments, 6 from government localities, 2 from professional medical organizations, and 19 from nongovernmental organizations. Out of the 2,420 clinics identified from the lists and Web searches, we removed 798 as duplicate entries, and we determined that 350 were ineligible for listing. The most common reasons for ineligibility were not having the appropriate medical licensure to prescribe PrEP (67/350) or not prescribing PrEP, based on self-report (192/350). Key informant interviews shaped important protocol decisions, such as listing clinics instead of individual clinicians as the primary data element and streamlining data collection to facilitate scalability. We developed a Web interface to provide public access to the data, with geolocated data display, search filter functionality, a webform for public suggestions of new clinics, and a publicly available directory Web tool that can be embedded in websites

  8. Sample EP Flow Analysis of Severely Damaged Networks

    Energy Technology Data Exchange (ETDEWEB)

    Werley, Kenneth Alan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); McCown, Andrew William [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-10-12

    These are slides for a presentation at the working group meeting of the WESC SREMP Software Product Integration Team on sample EP flow analysis of severely damaged networks. The following topics are covered: ERCOT EP Transmission Model; Zoomed in to Houston and Overlaying StreetAtlas; EMPACT Solve/Dispatch/Shedding Options; QACS BaseCase Power Flow Solution; 3 Substation Contingency; Gen. & Load/100 Optimal Dispatch; Dispatch Results; Shed Load for Low V; Network Damage Summary; Estimated Service Areas (Potential); Estimated Outage Areas (potential).

  9. Improved charge separation efficiency of hematite photoanodes by coating an ultrathin p-type LaFeO3 overlayer

    Science.gov (United States)

    Fang, Tao; Guo, Yongsheng; Cai, Songhua; Zhang, Ningsi; Hu, Yingfei; Zhang, Shiying; Li, Zhaosheng; Zou, Zhigang

    2017-09-01

    Many metal-oxide candidates for photoelectrochemical water splitting exhibit localized small polaron carrier conduction. Especially hematite (α-Fe2O3) photoanodes often suffer from low carrier mobility, which causes the serious bulk electron-hole recombination and greatly limits their PEC performances. In this study, the charge separation efficiency of hematite was enhanced greatly by coating an ultrathin p-type LaFeO3 overlayer. Compared to the hematite photoanodes, the solar water splitting photocurrent of the Fe2O3/LaFeO3 n-p junction exhibits a 90% increase at 1.23 V versus the reversible hydrogen electrode, due to enlarging the band bending and expanding the depletion layer.

  10. Road-runoff metal concentrations in Toledo, Ohio, and their relation to average daily traffic and age of pavement overlay.

    Science.gov (United States)

    Apul, D S; Miller, E; Jain, V

    2010-01-01

    Road runoff can contain metal concentrations and sampling of it can be expensive if auto-samplers are used. In this study, an inexpensive storm water sampling apparatus was developed and used for collecting the road runoff at eleven different sites in Toledo area. Sites were selected with the purpose of evaluating the effects of average daily traffic (ADT) and the age of pavement overlay on road runoff metal concentrations. Ag, As, Cd, and Mo concentrations were primarily below detection limit. Ba, Mn, Ni, Cu, Pb, and Zn were observed in higher concentrations but lower than pavement surface; with time, as the pavement aged, these sources appeared to be depleted as observed by lower runoff concentrations in older pavements.

  11. Development of diagnostic concentrations for insecticide resistance monitoring in soybean looper (Lepidoptera: Noctuidae) larvae using an artificial diet overlay bioassay.

    Science.gov (United States)

    Mascarenhas, R N; Boethel, D J

    2000-06-01

    Diagnostic concentrations for several standard and experimental insecticides were determined for a laboratory reference strain of soybean looper, Pseudoplusia includens (Walker), using an insecticide diet overlay bioassay to evaluate the relative susceptibility of field (P) and F1 generations of four field-collected strains of third-, fourth-, and fifth-instar soybean loopers in 1996 and 1997. Diagnostic concentrations were defined as concentrations that killed 90-95% of the susceptible individuals and were 5 ppm for permethrin, 1,300 ppm for thiodicarb, 60 ppm for chlorfenapyr, 5 ppm for emamectin benzoate, and 60 ppm for spinosad. Field strains exhibited significantly greater percentage survival than the laboratory reference strain in the permethrin bioassays in 1996 and 1997 in both the P and F1 generation bioassays and in the thiodicarb bioassays in 1997. Larvae exposed to diagnostic concentrations of the experimental insecticides chlorfenapyr, emamectin benzoate, and spinosad usually did not exhibit significantly higher percentage survival than the reference strain.

  12. Influence of different cavity preparation designs on fracture resistance of onlay and overlay restorations using different CAD/CAM materials.

    Science.gov (United States)

    Ön Salman, Gizem; Tacír, Ɣbrahim Halil; Polat, Zelal Seyfioğlu; Salman, Afşin

    2017-06-01

    To evaluate fracture strength of different preparation designed onlay and overlay restorations produced by Computer Aided Design/Computer Aided Manufacturing (CAD/CAM) and three different new ceramic-polymer blocks. Ninety-one extracted human mandibular molars were used in this study. Preparations were made as (1) Only functional cusps reduction, (2) Only functional cusps reduction+rounded shoulder finish line, (3) All cusps reduction, or (4) All cusps reduction+rounded shoulder finish line. Then these four cavity types were restored with three different materials: VITA Enamic, GC Cerasmart, Lava Ultimate. Thirteen groups were created by added control group (n= 7). Adhesive cementation was achieved by using a dual cured composite resin adhesive cement RelyX Ultimate. All samples were subjected to thermocycling for 5,000 cycles in water baths between 50°C and 55°C. The fracture resistance of specimens was determined under compressive loads along the long axis of the restored teeth at 0.5 mm/minute crosshead speed until fracture with a universal test machine. Fracture types of restored groups were evaluated. For fracture resistance data, one-way ANOVA; for correlation between material type and preparation design, two-way ANOVA were used. Percentage table and Kruskal-Wallis test were performed for analysis of fracture types. There was no significant difference between all the groups (one-way ANOVA, P> 0.05). Group 4 showed statistically higher fracture strength values than Group 1 and no significant difference was found among other preparation designs by two-way ANOVA that compared all types of preparation designs regardless of material difference (Pmaterials and type of preparations should be selected for onlay and overlay restorations produced with newly introduced ceramic-polymer CAD/CAM materials.

  13. The effect of a fiber reinforced cavity configuration on load bearing capacity and failure mode of endodontically treated molars restored with CAD/CAM resin composite overlay restorations

    NARCIS (Netherlands)

    Rocca, G.T.; Saratti, C.M.; Cattani-Lorente, M.; Feilzer, A.J.; Scherrer, S.; Krecji, I.

    2015-01-01

    Objectives To evaluate the fracture strength and the mode of failure of endodontically treated molars restored with CAD/CAM overlays with fiber reinforced composite build-up of the pulp chamber. Methods 40 Devitalized molars were cut over the CEJ and divided into five groups (n = 8). The pulp

  14. Improved antifouling properties and selective biofunctionalization of stainless steel by employing heterobifunctional silane-polyethylene glycol overlayers and avidin-biotin technology

    Science.gov (United States)

    Hynninen, Ville; Vuori, Leena; Hannula, Markku; Tapio, Kosti; Lahtonen, Kimmo; Isoniemi, Tommi; Lehtonen, Elina; Hirsimäki, Mika; Toppari, J. Jussi; Valden, Mika; Hytönen, Vesa P.

    2016-07-01

    A straightforward solution-based method to modify the biofunctionality of stainless steel (SS) using heterobifunctional silane-polyethylene glycol (silane-PEG) overlayers is reported. Reduced nonspecific biofouling of both proteins and bacteria onto SS and further selective biofunctionalization of the modified surface were achieved. According to photoelectron spectroscopy analyses, the silane-PEGs formed less than 10 Å thick overlayers with close to 90% surface coverage and reproducible chemical compositions. Consequently, the surfaces also became more hydrophilic, and the observed non-specific biofouling of proteins was reduced by approximately 70%. In addition, the attachment of E. coli was reduced by more than 65%. Moreover, the potential of the overlayer to be further modified was demonstrated by successfully coupling biotinylated alkaline phosphatase (bAP) to a silane-PEG-biotin overlayer via avidin-biotin bridges. The activity of the immobilized enzyme was shown to be well preserved without compromising the achieved antifouling properties. Overall, the simple solution-based approach enables the tailoring of SS to enhance its activity for biomedical and biotechnological applications.

  15. TEM Microstructure and Chemical Composition of Transition Zone Between Steel Tube and An Inconel 625 Weld Overlay Coating Produced by CMT Method

    OpenAIRE

    Rozmus-Górnikowska M.; Blicharski M.

    2017-01-01

    The aim of this work was to investigate the microstructure and chemical composition of the transition zone between 16Mo3 steel and Inconel 625 weld overlay coating produced by the Cold Metal Transfer (CMT) method. Investigations were primarily carried out through transmission electron microscopy (TEM) on thin foils prepared by FIB (Focus Ion Beam).

  16. TEM Microstructure and Chemical Composition of Transition Zone Between Steel Tube and An Inconel 625 Weld Overlay Coating Produced by CMT Method

    Directory of Open Access Journals (Sweden)

    Rozmus-Górnikowska M.

    2017-06-01

    Full Text Available The aim of this work was to investigate the microstructure and chemical composition of the transition zone between 16Mo3 steel and Inconel 625 weld overlay coating produced by the Cold Metal Transfer (CMT method. Investigations were primarily carried out through transmission electron microscopy (TEM on thin foils prepared by FIB (Focus Ion Beam.

  17. Adsorption and dissociation of SO3 on N-doped TiO2 supported Au overlayers investigated by van der Waals corrected DFT

    Science.gov (United States)

    Abbasi, Amirali; Sardroodi, Jaber Jahanbin

    2017-09-01

    We present a density functional theory (DFT) study of the reactivity towards SO3 adsorption and dissociation over the TiO2 supported Au overlayers. We model different adsorption configurations of SO3 on the considered structures. For all adsorption systems, we find that the interaction of SO3 molecule with the surfaces of Au atoms is strongly favored. On the TiO2 supported Au overlayer, SO3 also dissociated into SO2 and adsorbed atomic oxygen. The atomic oxygen binds directly to the Au atoms. The structural properties are explained in terms of the bond lengths, bond angles and adsorption energies. The electronic structure of the system and Mulliken population analysis were also studied for the discussion of results. The results indicate that the SO3 interaction with N-doped TiO2-supported Au overlayer is more favorable in energy than the interaction with undoped one, suggesting the increased sensing capability of N-doped TiO2-supported Au towards detection of SO3 molecule. The oxygen atoms of the SO3 molecule bind to the Au and Ti atoms of the TiO2 supported Au overlayer in a bridge geometry. The significant overlaps in the PDOSs of the Au and oxygen atoms of the SO3 molecule, as well as titanium and oxygen atoms indicate the formation of chemical bonds between these atoms. Our DFT study therefore provides a theoretical basis for why the reactivity of SO3 molecule with N-doped TiO2 supported Au overlayer may increase, thus being a helpful procedure in the development of efficient sensor devices for SO3 detection.

  18. Generation of nanocrystalline surface layer in short pulse laser processing of metal targets under conditions of spatial confinement by solid or liquid overlayer

    Science.gov (United States)

    Shugaev, Maxim V.; Shih, Cheng-Yu; Karim, Eaman T.; Wu, Chengping; Zhigilei, Leonid V.

    2017-09-01

    The effect of spatial confinement by a solid or liquid overlayer on short pulse laser-induced surface microstructure modification is investigated in a series of large-scale atomistic simulations performed for Ag targets irradiated in the regime of melting and resolidification, below the thresholds for laser spallation and ablation. For Ag targets with free surfaces, the formation of a nanocrystalline region with random crystallographic grain orientation is observed under irradiation conditions leading to the generation of numerous sub-surface voids that slow down the solidification process. When no voids are generated, the resolidification produces grains misoriented with respect to the bulk of the target by just several degrees and separated from each other by low angle grain boundaries or dislocation walls. The presence of a liquid or solid overlayer suppresses nucleation of sub-surface voids, provides an additional pathway for cooling through the heat conduction to the overlayer, and facilitates the formation of nanocrystalline structure in a region of the metal target adjacent to the overlayer. Moreover, the stabilizing effect of the solid overlayer may result in an incomplete melting of metal in the vicinity of the interface, making it possible for grains growing from the interface to retain ;memory; of the target orientation and to produce nanocrystalline interfacial region with small misorientation of grains with respect to the bulk of the target. In all simulations, the nanocrystalline layers generated by laser processing of single crystal Ag targets are characterized by a high density of stacking faults, twin boundaries, and point defects produced in the course of the rapid resolidification.

  19. Modeling and optimization of cloud-ready and content-oriented networks

    CERN Document Server

    Walkowiak, Krzysztof

    2016-01-01

    This book focuses on modeling and optimization of cloud-ready and content-oriented networks in the context of different layers and accounts for specific constraints following from protocols and technologies used in a particular layer. It addresses a wide range of additional constraints important in contemporary networks, including various types of network flows, survivability issues, multi-layer networking, and resource location. The book presents recent existing and new results in a comprehensive and cohesive way. The contents of the book are organized in five chapters, which are mostly self-contained. Chapter 1 briefly presents information on cloud computing and content-oriented services, and introduces basic notions and concepts of network modeling and optimization. Chapter 2 covers various optimization problems that arise in the context of connection-oriented networks. Chapter 3 focuses on modeling and optimization of Elastic Optical Networks. Chapter 4 is devoted to overlay networks. The book concludes w...

  20. A Fuzzy Preprocessing Module for Optimizing the Access Network Selection in Wireless Networks

    Directory of Open Access Journals (Sweden)

    Faisal Kaleem

    2013-01-01

    Full Text Available A heterogeneous wireless network is characterized by the presence of different wireless access technologies that coexist in an overlay fashion. These wireless access technologies usually differ in terms of their operating parameters. On the other hand, Mobile Stations (MSs in a heterogeneous wireless network are equipped with multiple interfaces to access different types of services from these wireless access technologies. The ultimate goal of these heterogeneous wireless networks is to provide global connectivity with efficient ubiquitous computing to these MSs based on the Always Best Connected (ABC principle. This is where the need for intelligent and efficient Vertical Handoffs (VHOs between wireless technologies in a heterogeneous environment becomes apparent. This paper presents the design and implementation of a fuzzy multicriteria based Vertical Handoff Necessity Estimation (VHONE scheme that determines the proper time for VHO, while considering the continuity and quality of the currently utilized service, and the end-users' satisfaction.

  1. Implementation of quantum key distribution network simulation module in the network simulator NS-3

    Science.gov (United States)

    Mehic, Miralem; Maurhart, Oliver; Rass, Stefan; Voznak, Miroslav

    2017-10-01

    As the research in quantum key distribution (QKD) technology grows larger and becomes more complex, the need for highly accurate and scalable simulation technologies becomes important to assess the practical feasibility and foresee difficulties in the practical implementation of theoretical achievements. Due to the specificity of the QKD link which requires optical and Internet connection between the network nodes, to deploy a complete testbed containing multiple network hosts and links to validate and verify a certain network algorithm or protocol would be very costly. Network simulators in these circumstances save vast amounts of money and time in accomplishing such a task. The simulation environment offers the creation of complex network topologies, a high degree of control and repeatable experiments, which in turn allows researchers to conduct experiments and confirm their results. In this paper, we described the design of the QKD network simulation module which was developed in the network simulator of version 3 (NS-3). The module supports simulation of the QKD network in an overlay mode or in a single TCP/IP mode. Therefore, it can be used to simulate other network technologies regardless of QKD.

  2. Design of energy efficient optical networks with software enabled integrated control plane

    DEFF Research Database (Denmark)

    Wang, Jiayuan; Yan, Ying; Dittmann, Lars

    2015-01-01

    energy consumption by proposing a new integrated control plane structure utilising Software Defined Networking technologies. The integrated control plane increases the efficiencies of exchanging control information across different network domains, while introducing new possibilities to the routing...... methods and the control over quality of service (QoS). The structure is defined as an overlay generalised multi-protocol label switching (GMPLS) control model. With the defined structure, the integrated control plane is able to gather information from different domains (i.e. optical core network...

  3. Real-time augmented reality overlay for an energy-efficient car study

    Science.gov (United States)

    Wozniak, Peter; Javahiraly, Nicolas; Curticapean, Dan

    2017-06-01

    Our university carries out various research projects. Among others, the project Schluckspecht is an interdisciplinary work on different ultra-efficient car concepts for international contests. Besides the engineering work, one part of the project deals with real-time data visualization. In order to increase the efficiency of the vehicle, an online monitoring of the runtime parameters is necessary. The driving parameters of the vehicle are transmitted to a processing station via a wireless network connection. We plan to use an augmented reality (AR) application to visualize different data on top of the view of the real car. By utilizing a mobile Android or iOS device a user can interactively view various real-time and statistical data. The car and its components are meant to be augmented by various additional information, whereby that information should appear at the correct position of the components. An engine e.g. could show the current rpm and consumption values. A battery on the other hand could show the current charge level. The goal of this paper is to evaluate different possible approaches, their suitability and to expand our application to other projects at our university.

  4. TU-FG-BRB-09: Thermoacoustic Range Verification with Perfect Co-Registered Overlay of Bragg Peak onto Ultrasound Image

    Energy Technology Data Exchange (ETDEWEB)

    Patch, S; Kireeff Covo, M; Jackson, A; Qadadha, Y; Campbell, K; Albright, R; Bloemhard, P; Donoghue, A; Siero, C; Gimpel, T; Small, S; Ninemire, B; Johnson, M; Phair, L [Lawrence Berkeley National Lab, Berkeley, CA (United States)

    2016-06-15

    Purpose: The potential of particle therapy has not yet been fully realized due to inaccuracies in range verification. The purpose of this work was to correlate the Bragg peak location with target structure, by overlaying thermoacoustic localization of the Bragg peak onto an ultrasound image. Methods: Pulsed delivery of 50 MeV protons was accomplished by a fast chopper installed between the ion source and the inflector of the 88″ cyclotron at Lawrence Berkeley National Lab. 2 Gy were delivered in 2 µs by a beam with peak current of 2 µA. Thermoacoustic emissions were detected by a cardiac array and Verasonics V1 ultrasound system, which also generated a grayscale ultrasound image. 1024 thermoacoustic pulses were averaged before filtering and one-way beamforming focused signal onto the Bragg peak location with perfect co-registration to the ultrasound images. Data was collected in a room temperature water bath and gelatin phantom with a cavity designed to mimic the intestine, in which gas pockets can displace the Bragg peak. Experiments were performed with the cavity both empty and filled with olive oil. Results: In the waterbath overlays of the Bragg peak agreed with Monte Carlo simulations to within 800±170 µm. Agreement within 1.3 ± 0.2 mm was achieved in the gelatin phantom, although relative stopping powers were estimated only to first order from CT scans. Protoacoustic signals were detected after travel from the Bragg peak through 29 mm and 65 mm of phantom material when the cavity was empty and full of olive oil, respectively. Conclusion: Protoacoustic range verification is feasible with a commercial clinical ultrasound array, but at doses exceeding the clinical realm. Further optimization of both transducer array and injection line chopper is required to enable range verification within a 2 Gy dose limit, which would enable online adaptive treatment. This work was supported in part by a UWM Intramural Instrumentation Grant and by the Director, Office

  5. Learning Networks, Networked Learning

    NARCIS (Netherlands)

    Sloep, Peter; Berlanga, Adriana

    2010-01-01

    Sloep, P. B., & Berlanga, A. J. (2011). Learning Networks, Networked Learning [Redes de Aprendizaje, Aprendizaje en Red]. Comunicar, XIX(37), 55-63. Retrieved from http://dx.doi.org/10.3916/C37-2011-02-05

  6. Wireless data over RAM's Mobitex network

    Science.gov (United States)

    Khan, M. Mobeen

    1995-12-01

    Mobitex is a mobile data technology standard created by Eritel, now a wholly owned subsidiary of Ericsson, that has been in existence for about a decade. Originally designed as a low speed (1.2 kbps) data system with a voice dispatch overlay, it was significantly enhanced in 1990 for use in North America and the UK. The enhanced system is a data-only system using cellular architecture and multi-channel frequency reuse, store-and-forward capability, and an 8 kbps over-the-air data rate. The mission of RAM Mobile Data USA Limited Partnership ('RAM') is to provide high quality, cost efficient, wireless data communications solutions in its targeted market segments. RAM's Mobitex network is currently one of the two networks providing two way wireless data services nationwide using a long distance service provider of the customer's choice.

  7. Structure and energetics of hydrogen-bonded networks of methanol on close packed transition metal surfaces

    Science.gov (United States)

    Murphy, Colin J.; Carrasco, Javier; Lawton, Timothy J.; Liriano, Melissa L.; Baber, Ashleigh E.; Lewis, Emily A.; Michaelides, Angelos; Sykes, E. Charles H.

    2014-07-01

    Methanol is a versatile chemical feedstock, fuel source, and energy storage material. Many reactions involving methanol are catalyzed by transition metal surfaces, on which hydrogen-bonded methanol overlayers form. As with water, the structure of these overlayers is expected to depend on a delicate balance of hydrogen bonding and adsorbate-substrate bonding. In contrast to water, however, relatively little is known about the structures methanol overlayers form and how these vary from one substrate to another. To address this issue, herein we analyze the hydrogen bonded networks that methanol forms as a function of coverage on three catalytically important surfaces, Au(111), Cu(111), and Pt(111), using a combination of scanning tunneling microscopy and density functional theory. We investigate the effect of intermolecular interactions, surface coverage, and adsorption energies on molecular assembly and compare the results to more widely studied water networks on the same surfaces. Two main factors are shown to direct the structure of methanol on the surfaces studied: the surface coverage and the competition between the methanol-methanol and methanol-surface interactions. Additionally, we report a new chiral form of buckled hexamer formed by surface bound methanol that maximizes the interactions between methanol monomers by sacrificing interactions with the surface. These results serve as a direct comparison of interaction strength, assembly, and chirality of methanol networks on Au(111), Cu(111), and Pt(111) which are catalytically relevant for methanol oxidation, steam reforming, and direct methanol fuel cells.

  8. A network of networks.

    Science.gov (United States)

    Iedema, Rick; Verma, Raj; Wutzke, Sonia; Lyons, Nigel; McCaughan, Brian

    2017-04-10

    Purpose To further our insight into the role of networks in health system reform, the purpose of this paper is to investigate how one agency, the NSW Agency for Clinical Innovation (ACI), and the multiple networks and enabling resources that it encompasses, govern, manage and extend the potential of networks for healthcare practice improvement. Design/methodology/approach This is a case study investigation which took place over ten months through the first author's participation in network activities and discussions with the agency's staff about their main objectives, challenges and achievements, and with selected services around the state of New South Wales to understand the agency's implementation and large system transformation activities. Findings The paper demonstrates that ACI accommodates multiple networks whose oversight structures, self-organisation and systems change approaches combined in dynamic ways, effectively yield a diversity of network governances. Further, ACI bears out a paradox of "centralised decentralisation", co-locating agents of innovation with networks of implementation and evaluation expertise. This arrangement strengthens and legitimates the role of the strategic hybrid - the healthcare professional in pursuit of change and improvement, and enhances their influence and impact on the wider system. Research limitations/implications While focussing the case study on one agency only, this study is unique as it highlights inter-network connections. Contributing to the literature on network governance, this paper identifies ACI as a "network of networks" through which resources, expectations and stakeholder dynamics are dynamically and flexibly mediated and enhanced. Practical implications The co-location of and dynamic interaction among clinical networks may create synergies among networks, nurture "strategic hybrids", and enhance the impact of network activities on health system reform. Social implications Network governance requires more

  9. Identification of an incommensurate FeAl{sub 2} overlayer on FeAl(110) using x-ray diffraction and reflectivity

    Energy Technology Data Exchange (ETDEWEB)

    Baddorf, A.P. [Oak Ridge National Lab., TN (United States); Chandavarkar, S.S. [Tennessee Univ., Knoxville, TN (United States). Dept. of Physics and Astronomy

    1995-06-30

    FeAl, like NiAl, crystallizes in the CsCl structure. Consequently the (110) planes contain equal amounts of Fe and Al distributed as interlocking rectangles. Unlike the NiAI(110) surface, which retains the (1{times}l) in-plane symmetry of the bulk, FeAl(l10) reconstructs to form an ordered, incommensurate overlayer. The reconstructed layer introduces x-ray diffraction rods at half-order positions along the [1{bar 1}0] direction, and displaced {plus_minus}0.2905 from integer positions along the [001] direction. Peak widths reveal excellent long range order. Specular reflectivity measurements above and below the Fe K{alpha} edge can be reproduced using a model containing a single reconstructed overlayer with an Fe:Al ratio of 1:2, consistent with FeA{sub I}2.

  10. Microstructural changes of a thermally aged stainless steel submerged arc weld overlay cladding of nuclear reactor pressure vessels

    Science.gov (United States)

    Takeuchi, T.; Kameda, J.; Nagai, Y.; Toyama, T.; Matsukawa, Y.; Nishiyama, Y.; Onizawa, K.

    2012-06-01

    The effect of thermal aging on microstructural changes in stainless steel submerged arc weld-overlay cladding of reactor pressure vessels was investigated using atom probe tomography (APT). In as-received materials subjected to post-welding heat treatments (PWHTs), with a subsequent furnace cooling, a slight fluctuation of the Cr concentration was observed due to spinodal decomposition in the δ-ferrite phase but not in the austenitic phase. Thermal aging at 400 °C for 10,000 h caused not only an increase in the amplitude of spinodal decomposition but also the precipitation of G phases with composition ratios of Ni:Si:Mn = 16:7:6 in the δ-ferrite phase. The degree of the spinodal decomposition in the submerged arc weld sample was similar to that in the electroslag weld one reported previously. We also observed a carbide on the γ-austenite and δ-ferrite interface. There were no Cr depleted zones around the carbide.

  11. Estimation of intrinsic aquifer vulnerability with index-overlay and statistical methods: the case of eastern Kopaida, central Greece

    Science.gov (United States)

    Tziritis, E.; Lombardo, L.

    2017-09-01

    The intrinsic vulnerability of a karstic aquifer system in central Greece was jointly assessed with the use of a statistical approach and PI method, as a function of topography, protective cover effectiveness and the degree to which this cover is bypassed due to flow conditions. The input data for the index-overlay PI method were derived from field works and 71 boreholes of the area; the information was obtained, subsequently its critical factors were compiled which included lithology, fissuring and karstification of bedrock, soil characteristics, hydrology, hydrogeology, topography and vegetation. The aforementioned parameters were processed jointly with the aid of a GIS and yielded the final estimation of intrinsic aquifer vulnerability to contamination. Results were compared with an equivalent spatially distributed probability map obtained through a stochastic approach. The calibration and test phase of the latter relied on morphometric conditions derived by terrain analyses of a digital elevation model as well as on geology and land use from thematic maps. This procedure allowed taking into account the topographic influences with respect to a deep system such as the local karstic aquifer of eastern Kopaida basin. Finally, results were validated with ground truth nitrate values obtained from 41 groundwater samples, highlighted the spatial delineation of susceptible areas to contamination in both cases and provided a robust tool for regional planning actions and water resources management schemes.

  12. Strain distribution and crack detection in thin unbonded concrete pavement overlays with fully distributed fiber optic sensors

    Science.gov (United States)

    Bao, Yi; Chen, Genda

    2016-01-01

    This study aims at evaluating the feasibility of strain measurement and crack detection in thin unbonded concrete pavement overlays with pulse prepump Brillouin optical time domain analysis. Single-mode optical fibers with two-layer and three-layer coatings, respectively, were applied as fully distributed sensors, their performances were compared with analytical predictions. They were successfully protected from damage during concrete casting of three full-scale concrete panels when 5 to 10-cm-thick protective mortar covers had been set for 2 h. Experimental results from three-point loading tests of the panels indicated that the strain distributions measured from the two types of sensors were in good agreement, and cracks can be detected at sharp peaks of the measured strain distributions. The two-layer and three-layer coated fibers can be used to measure strains up to 2.33% and 2.42% with a corresponding sensitivity of 5.43×10-5 and 4.66×10-5 GHz/μɛ, respectively. Two cracks as close as 7 to 9 cm can be clearly detected. The measured strains in optical fiber were lower than the analytical prediction by 10% to 25%. Their difference likely resulted from strain transfer through various coatings, idealized point loading, varying optical fiber embedment, and concrete heterogeneity.

  13. Joint Bandwidth and Power Allocation for MIMO Two-Way Relays-Assisted Overlay Cognitive Radio Systems

    KAUST Repository

    Alsharoa, Ahmad

    2015-10-08

    This paper studies the achievable cognitive sum rate of an overlay cognitive radio (CR) system assisted with multiple antennas two-way relays in which primary users (PUs) cooperate with cognitive users (CUs) for mutual benefits. In this context, the problem of both bandwidth and power allocation is investigated. We propose that the CUs are allowed to allocate a part of the PUs spectrum to perform their cognitive transmission. In return, acting as amplify-and-forward two-way relays, they are exploited to support PUs to reach their target data rates over the remaining bandwidth. Power expressions for optimal transmit power allocated per PU and CU antenna are derived under primary quality-of-service constraint in addition to bandwidth and power budget constraints. More specifically, CUs act as relays for the PUs transmission and gain some spectrum as long as they respect these constraints. After deriving the optimal transmit powers, we employ a strong optimization tool based on swarm intelligence to optimize the full and complex relay amplification gain matrices in addition to the bandwidths released to primary and cognitive transmission. Furthermore, three different utility functions are considered in our optimization problems depending on the level of fairness among CUs.

  14. Effects of neutron irradiation on microstructures and hardness of stainless steel weld-overlay cladding of nuclear reactor pressure vessels

    Energy Technology Data Exchange (ETDEWEB)

    Takeuchi, T., E-mail: takeuchi.tomoaki@jaea.go.jp [Oarai Research and Development Center, Japan Atomic Energy Agency, Oarai, Ibaraki 311-1393 (Japan); Kakubo, Y.; Matsukawa, Y.; Nozawa, Y.; Toyama, T.; Nagai, Y. [The Oarai Center, Institute for Materials Research, Tohoku University, Oarai, Ibaraki 311-1313 (Japan); Nishiyama, Y.; Katsuyama, J.; Yamaguchi, Y.; Onizawa, K. [Nuclear Safety Research Center, Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195 (Japan)

    2014-06-01

    The microstructures and the hardness of stainless steel weld overlay cladding of reactor pressure vessels subjected to neutron irradiation at a dose of 7.2 × 10{sup 19} n cm{sup −2} (E > 1 MeV) and a flux of 1.1 × 10{sup 13} n cm{sup −2} s{sup −1} at 290 °C were investigated by atom probe tomography and by a nanoindentation technique. To isolate the effects of the neutron irradiation, we compared the results of the measurements of the neutron-irradiated samples with those from a sample aged at 300 °C for a duration equivalent to that of the irradiation. The Cr concentration fluctuation was enhanced in the δ-ferrite phase of the irradiated sample. In addition, enhancement of the concentration fluctuation of Si, which was not observed in the aged sample, was observed. The hardening in the δ-ferrite phase occurred due to both irradiation and aging; however, the hardening of the irradiated sample was more than that expected from the Cr concentration fluctuation, which suggested that the Si concentration fluctuation and irradiation-induced defects were possible origins of the additional hardening.

  15. Effects of thermal aging on microstructure and hardness of stainless steel weld-overlay claddings of nuclear reactor pressure vessels

    Energy Technology Data Exchange (ETDEWEB)

    Takeuchi, T., E-mail: takeuchi.tomoaki@jaea.go.jp [Japan Atomic Energy Agency, Oarai, Ibaraki 311-1393 (Japan); Kakubo, Y.; Matsukawa, Y.; Nozawa, Y.; Toyama, T.; Nagai, Y. [The Oarai Center, Institute for Materials Research, Tohoku University, Oarai, Ibaraki 311-1313 (Japan); Nishiyama, Y.; Katsuyama, J.; Yamaguchi, Y.; Onizawa, K. [Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195 (Japan); Suzuki, M. [Japan Atomic Energy Agency, Oarai, Ibaraki 311-1393 (Japan)

    2014-09-15

    The effects of thermal aging of stainless steel weld-overlay claddings of nuclear reactor pressure vessels on the microstructure and hardness of the claddings were investigated using atom probe tomography and nanoindentation testing. The claddings were aged at 400 °C for periods of 100–10,000 h. The fluctuation in Cr concentration in the δ-ferrite phase, which was caused by spinodal decomposition, progressed rapidly after aging for 100 h, and gradually for aging durations greater than 1000 h. On the other hand, NiSiMn clusters, initially formed after aging for less than 1000 h, had the highest number density after aging for 2000 h, and coarsened after aging for 10,000 h. The hardness of the δ-ferrite phase also increased rapidly for short period of aging, and saturated after aging for longer than 1000 h. This trend was similar to the observed Cr fluctuation concentration, but different from the trend seen in the formation of the NiSiMn clusters. These results strongly suggest that the primary factor responsible for the hardening of the δ-ferrite phase owing to thermal aging is Cr spinodal decomposition.

  16. Estimation of intrinsic aquifer vulnerability with index-overlay and statistical methods: the case of eastern Kopaida, central Greece

    KAUST Repository

    Tziritis, E.

    2016-03-01

    The intrinsic vulnerability of a karstic aquifer system in central Greece was jointly assessed with the use of a statistical approach and PI method, as a function of topography, protective cover effectiveness and the degree to which this cover is bypassed due to flow conditions. The input data for the index-overlay PI method were derived from field works and 71 boreholes of the area; the information was obtained, subsequently its critical factors were compiled which included lithology, fissuring and karstification of bedrock, soil characteristics, hydrology, hydrogeology, topography and vegetation. The aforementioned parameters were processed jointly with the aid of a GIS and yielded the final estimation of intrinsic aquifer vulnerability to contamination. Results were compared with an equivalent spatially distributed probability map obtained through a stochastic approach. The calibration and test phase of the latter relied on morphometric conditions derived by terrain analyses of a digital elevation model as well as on geology and land use from thematic maps. This procedure allowed taking into account the topographic influences with respect to a deep system such as the local karstic aquifer of eastern Kopaida basin. Finally, results were validated with ground truth nitrate values obtained from 41 groundwater samples, highlighted the spatial delineation of susceptible areas to contamination in both cases and provided a robust tool for regional planning actions and water resources management schemes.

  17. A Treatment Protocol for Restoring Occlusal Vertical Dimension Using an Overlay Removable Partial Denture as an Alternative to Extensive Fixed Restorations: A Clinical Report

    OpenAIRE

    Patel, Mit B; Bencharit, Sompop

    2009-01-01

    Treatment options for patients with severe attrition resulting in reduced occlusal vertical dimension are often limited to fixed prosthesis to reestablish proper occlusal vertical dimension and functional occlusion. In some cases such as when there are limited finances, minimal esthetic concerns, and medical considerations fixed prosthesis may not be the ideal treatment option. Overlay removable partial dentures (ORPDs) can be used as a provisional or interim prosthesis as well as permanent p...

  18. SMEX03 Geolocation Information: Georgia

    Data.gov (United States)

    National Aeronautics and Space Administration — Notice to Data Users: The documentation for this data set was provided solely by the Principal Investigator(s) and was not further developed, thoroughly reviewed, or...

  19. Dissimilar steel welding and overlay covering with nickel based alloys using SWAM (Shielded Metal Arc Welding) and GTAW (Gas Tungsten Arc Welding) processes in the nuclear industry

    Energy Technology Data Exchange (ETDEWEB)

    Arce Chilque, Angel Rafael [Centro Tecnico de Engenharia e Inovacao Empresarial Ltda., Belo Horizonte, MG (Brazil); Bracarense, Alexander Queiroz; Lima, Luciana Iglesias Lourenco [Federal University of Minas Gerais (UFMG), Belo Horizonte, MG (Brazil); Quinan, Marco Antonio Dutra; Schvartzman, Monica Maria de Abreu Mendonca [Nuclear Technology Development Centre (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil); Marconi, Guilherme [Federal Center of Technological Education (CEFET-MG), Belo Horizonte, MG (Brazil)

    2009-07-01

    This work presents the welding of dissimilar ferritic steel type A508 class 3 and austenitic stainless steel type AISI 316 L using Inconel{sup R} 600 (A182 and A82) and overlay covering with Inconel{sup R} 690 (A52) as filler metal. Dissimilar welds with these materials without defects and weldability problems such as hot, cold, reheat cracking and Ductility Dip Crack were obtained. Comparables mechanical properties to those of the base metal were found and signalized the efficiency of the welding procedure and thermal treatment selected and used. This study evidences the importance of meeting compromised properties between heat affected zone of the ferritic steel and the others regions presents in the dissimilar joint, to elaborate the dissimilar metal welding procedure specification and weld overlay. Metallographic studies with optical microscopy and Vickers microhardness were carried out to justified and support the results, showing the efficiency of the technique of elaboration of dissimilar metal welding procedure and overlay. The results are comparables and coherent with the results found by others. Some alternatives of welding procedures are proposed to attain the efficacy. Further studies are proposed like as metallographic studies of the fine microstructure, making use, for example, of scanning electron microscope (SEM adapted with an EDS) to explain looking to increase the resistance to primary water stress corrosion (PWSCC) in nuclear equipment. (author)

  20. The anatomy of urban social networks and its implications in the searchability problem

    Science.gov (United States)

    Herrera-Yagüe, C.; Schneider, C. M.; Couronné, T.; Smoreda, Z.; Benito, R. M.; Zufiria, P. J.; González, M. C.

    2015-01-01

    The appearance of large geolocated communication datasets has recently increased our understanding of how social networks relate to their physical space. However, many recurrently reported properties, such as the spatial clustering of network communities, have not yet been systematically tested at different scales. In this work we analyze the social network structure of over 25 million phone users from three countries at three different scales: country, provinces and cities. We consistently find that this last urban scenario presents significant differences to common knowledge about social networks. First, the emergence of a giant component in the network seems to be controlled by whether or not the network spans over the entire urban border, almost independently of the population or geographic extension of the city. Second, urban communities are much less geographically clustered than expected. These two findings shed new light on the widely-studied searchability in self-organized networks. By exhaustive simulation of decentralized search strategies we conclude that urban networks are searchable not through geographical proximity as their country-wide counterparts, but through an homophily-driven community structure. PMID:26035529

  1. Recommender systems for location-based social networks

    CERN Document Server

    Symeonidis, Panagiotis; Manolopoulos, Yannis

    2014-01-01

    Online social networks collect information from users' social contacts and their daily interactions (co-tagging of photos, co-rating of products etc.) to provide them with recommendations of new products or friends. Lately, technological progressions in mobile devices (i.e. smart phones) enabled the incorporation of geo-location data in the traditional web-based online social networks, bringing the new era of Social and Mobile Web. The goal of this book is to bring together important research in a new family of recommender systems aimed at serving Location-based Social Networks (LBSNs). The chapters introduce a wide variety of recent approaches, from the most basic to the state-of-the-art, for providing recommendations in LBSNs. The book is organized into three parts. Part 1 provides introductory material on recommender systems, online social networks and LBSNs. Part 2 presents a wide variety of recommendation algorithms, ranging from basic to cutting edge, as well as a comparison of the characteristics of t...

  2. Overlay Tool© for aCGHViewer©: An Analysis Module Built for aCGHViewer© used to Perform Comparisons of Data Derived from Different Microarray Platforms

    Directory of Open Access Journals (Sweden)

    Ken C. Lo

    2007-01-01

    Full Text Available The Overlay Tool© has been developed to combine high throughput data derived from various microarray platforms. This tool analyzes high-resolution correlations between gene expression changes and either copy number abnormalities (CNAs or loss of heterozygosity events detected using array comparative genomic hybridization (aCGH. Using an overlay analysis which is designed to be performed using data from multiple microarray platforms on a single biological sample, the Overlay Tool© identifi es potentially important genes whose expression profiles are changed as a result of losses, gains and amplifi cations in the cancer genome. In addition, the Overlay Tool© will incorporate loss of heterozygosity (LOH probability data into this overlay procedure. To facilitate this analysis, we developed an application which computationally combines two or more high throughput datasets (e.g. aCGH/expression into a single categorized dataset for visualization and interrogation using a gene-centric approach. As such, data from virtually any microarray platform can be incorporated without the need to remap entire datasets individually. The resultant categorized (overlay data set can be conveniently viewed using our in-house visualization tool, aCGHViewer© (Shankar et al. 2006, which serves as a conduit to public databases such as UCSC and NCBI, to rapidly investigate genes of interest.

  3. A Survey on Security in Mobile Peer-to-Peer Architectures—Overlay-Based vs. Underlay-Based Approaches

    Directory of Open Access Journals (Sweden)

    Christian Gottron

    2010-10-01

    Full Text Available Mobile Ad hoc networks (MANET and Peer-to-Peer (P2P networks share central characteristics such as their distributed and decentralized nature. Combining both networking paradigms results in a Mobile Peer-to-Peer (MP2P system that operates independently from a preexisting infrastructure. Securing MP2P networks in terms of availability and robustness as basic demands in envisioned application scenarios like first responder operations is a challenging task. In this article, we present a survey of selected threats and of state of the art countermeasures for MANETs and P2P networks. Further, we discuss the efficiency of MANET and P2P security mechanisms when applied in MP2P networks.

  4. Delay Tolerant Networking on NASA's Space Communication and Navigation Testbed

    Science.gov (United States)

    Johnson, Sandra; Eddy, Wesley

    2016-01-01

    This presentation covers the status of the implementation of an open source software that implements the specifications developed by the CCSDS Working Group. Interplanetary Overlay Network (ION) is open source software and it implements specifications that have been developed by two international working groups through IETF and CCSDS. ION was implemented on the SCaN Testbed, a testbed located on an external pallet on ISS, by the GRC team. The presentation will cover the architecture of the system, high level implementation details, and issues porting ION to VxWorks.

  5. A Location-Aware Vertical Handoff Algorithm for Hybrid Networks

    KAUST Repository

    Mehbodniya, Abolfazl

    2010-07-01

    One of the main objectives of wireless networking is to provide mobile users with a robust connection to different networks so that they can move freely between heterogeneous networks while running their computing applications with no interruption. Horizontal handoff, or generally speaking handoff, is a process which maintains a mobile user\\'s active connection as it moves within a wireless network, whereas vertical handoff (VHO) refers to handover between different types of networks or different network layers. Optimizing VHO process is an important issue, required to reduce network signalling and mobile device power consumption as well as to improve network quality of service (QoS) and grade of service (GoS). In this paper, a VHO algorithm in multitier (overlay) networks is proposed. This algorithm uses pattern recognition to estimate user\\'s position, and decides on the handoff based on this information. For the pattern recognition algorithm structure, the probabilistic neural network (PNN) which has considerable simplicity and efficiency over existing pattern classifiers is used. Further optimization is proposed to improve the performance of the PNN algorithm. Performance analysis and comparisons with the existing VHO algorithm are provided and demonstrate a significant improvement with the proposed algorithm. Furthermore, incorporating the proposed algorithm, a structure is proposed for VHO from the medium access control (MAC) layer point of view. © 2010 ACADEMY PUBLISHER.

  6. Delay and Disruption Tolerant Networking MACHETE Model

    Science.gov (United States)

    Segui, John S.; Jennings, Esther H.; Gao, Jay L.

    2011-01-01

    To verify satisfaction of communication requirements imposed by unique missions, as early as 2000, the Communications Networking Group at the Jet Propulsion Laboratory (JPL) saw the need for an environment to support interplanetary communication protocol design, validation, and characterization. JPL's Multi-mission Advanced Communications Hybrid Environment for Test and Evaluation (MACHETE), described in Simulator of Space Communication Networks (NPO-41373) NASA Tech Briefs, Vol. 29, No. 8 (August 2005), p. 44, combines various commercial, non-commercial, and in-house custom tools for simulation and performance analysis of space networks. The MACHETE environment supports orbital analysis, link budget analysis, communications network simulations, and hardware-in-the-loop testing. As NASA is expanding its Space Communications and Navigation (SCaN) capabilities to support planned and future missions, building infrastructure to maintain services and developing enabling technologies, an important and broader role is seen for MACHETE in design-phase evaluation of future SCaN architectures. To support evaluation of the developing Delay Tolerant Networking (DTN) field and its applicability for space networks, JPL developed MACHETE models for DTN Bundle Protocol (BP) and Licklider/Long-haul Transmission Protocol (LTP). DTN is an Internet Research Task Force (IRTF) architecture providing communication in and/or through highly stressed networking environments such as space exploration and battlefield networks. Stressed networking environments include those with intermittent (predictable and unknown) connectivity, large and/or variable delays, and high bit error rates. To provide its services over existing domain specific protocols, the DTN protocols reside at the application layer of the TCP/IP stack, forming a store-and-forward overlay network. The key capabilities of the Bundle Protocol include custody-based reliability, the ability to cope with intermittent connectivity

  7. Determination of thickness of thin turbid painted over-layers using micro-scale spatially offset Raman spectroscopy

    Science.gov (United States)

    Conti, Claudia; Realini, Marco; Colombo, Chiara; Botteon, Alessandra; Bertasa, Moira; Striova, Jana; Barucci, Marco; Matousek, Pavel

    2016-12-01

    We present a method for estimating the thickness of thin turbid layers using defocusing micro-spatially offset Raman spectroscopy (micro-SORS). The approach, applicable to highly turbid systems, enables one to predict depths in excess of those accessible with conventional Raman microscopy. The technique can be used, for example, to establish the paint layer thickness on cultural heritage objects, such as panel canvases, mural paintings, painted statues and decorated objects. Other applications include analysis in polymer, biological and biomedical disciplines, catalytic and forensics sciences where highly turbid overlayers are often present and where invasive probing may not be possible or is undesirable. The method comprises two stages: (i) a calibration step for training the method on a well characterized sample set with a known thickness, and (ii) a prediction step where the prediction of layer thickness is carried out non-invasively on samples of unknown thickness of the same chemical and physical make up as the calibration set. An illustrative example of a practical deployment of this method is the analysis of larger areas of paintings. In this case, first, a calibration would be performed on a fragment of painting of a known thickness (e.g. derived from cross-sectional analysis) and subsequently the analysis of thickness across larger areas of painting could then be carried out non-invasively. The performance of the method is compared with that of the more established optical coherence tomography (OCT) technique on identical sample set. This article is part of the themed issue "Raman spectroscopy in art and archaeology".

  8. Effects of thermal aging and neutron irradiation on the mechanical properties of three-wire stainless steel weld overlay cladding

    Energy Technology Data Exchange (ETDEWEB)

    Haggag, F.M.; Nanstad, R.K.

    1997-05-01

    Thermal aging of three-wire series-arc stainless steel weld overlay cladding at 288{degrees}C for 1605 h resulted in an appreciable decrease (16%) in the Charpy V-notch (CVN) upper-shelf energy (USE), but the effect on the 41-J transition temperature shift was very small (3{degrees}C). The combined effect of aging and neutron irradiation at 288{degrees}C to a fluence of 5 x 10{sup 19} neutrons/cm{sup 2} (> 1 MeV) was a 22% reduction in the USE and a 29{degrees}C shift in the 41-J transition temperature. The effect of thermal aging on tensile properties was very small. However, the combined effect of irradiation and aging was an increase in the yield strength (6 to 34% at test temperatures from 288 to {minus}125{degrees}C) but no apparent change in ultimate tensile strength or total elongation. Neutron irradiation reduced the initiation fracture toughness (J{sub Ic}) much more than did thermal aging alone. Irradiation slightly decreased the tearing modulus, but no reduction was caused by thermal aging alone. Other results from tensile, CVN, and fracture toughness specimens showed that the effects of thermal aging at 288 or 343{degrees}C for 20,000 h each were very small and similar to those at 288{degrees}C for 1605 h. The effects of long-term thermal exposure time (50,000 h and greater) at 288{degrees}C will be investigated as the specimens become available in 1996 and beyond.

  9. Security Analysis of DTN Architecture and Bundle Protocol Specification for Space-Based Networks

    Science.gov (United States)

    Ivancic, William D.

    2009-01-01

    A Delay-Tolerant Network (DTN) Architecture (Request for Comment, RFC-4838) and Bundle Protocol Specification, RFC-5050, have been proposed for space and terrestrial networks. Additional security specifications have been provided via the Bundle Security Specification (currently a work in progress as an Internet Research Task Force internet-draft) and, for link-layer protocols applicable to Space networks, the Licklider Transport Protocol Security Extensions. This document provides a security analysis of the current DTN RFCs and proposed security related internet drafts with a focus on space-based communication networks, which is a rather restricted subset of DTN networks. Note, the original focus and motivation of DTN work was for the Interplanetary Internet . This document does not address general store-and-forward network overlays, just the current work being done by the Internet Research Task Force (IRTF) and the Consultative Committee for Space Data Systems (CCSDS) Space Internetworking Services Area (SIS) - DTN working group under the DTN and Bundle umbrellas. However, much of the analysis is relevant to general store-and-forward overlays.

  10. MODIS/Aqua 0.5 x 0.5 degree Aeronet cutouts of MODIS L1B Radiances, Geolocation, Cloud Mask, and ancillary data

    Data.gov (United States)

    National Aeronautics and Space Administration — The MYDARNSS data set consists of MODIS Atmosphere and Ancillary Products subsets that are generated over a number of Aerosol Robotic Network (AERONET) sites. These...

  11. MODIS/Aqua 0.5 x 0.5 degree FluxNet cutouts of MODIS L1B Radiances, Geolocation, Cloud Mask, and ancillary data

    Data.gov (United States)

    National Aeronautics and Space Administration — The MYDFNSS data set consists of MODIS Atmosphere and Ancillary Products subsets that are generated over a number of FLUXNET sites. FLUXNET is a network of...

  12. MODIS/Terra 0.5 x 0.5 degree FluxNet cutouts of MODIS L1B Radiances, Geolocation, Cloud Mask, and ancillary data

    Data.gov (United States)

    National Aeronautics and Space Administration — The MODFNSS data set consists of MODIS Atmosphere and Ancillary Products subsets that are generated over a number of FLUXNET sites. FLUXNET is a network of...

  13. A method for secure communications over a public fiber-optical network.

    Science.gov (United States)

    Wu, Bernard B; Narimanov, Evgenii E

    2006-05-01

    We develop a spread-spectrum based approach to secure communications over existing fiber-optical networks. Secure transmission for a dedicated user is achieved by overlaying a covert channel onto a host channel in the existing active fiber link. The covert channel is optically encoded and temporally spread, and has average power below the noise floor in the fiber, making it hidden for a direct detection thus allowing for cryptographic and steganographic security capabilities. The presence for the host channel in the network provides an ad hoc security expansion and increases the difficulty for an eavesdropper to intercept and decode the secure signal.

  14. Polyester polymer concrete overlay.

    Science.gov (United States)

    2013-01-01

    Polyester polymer concrete (PPC) was used in a trial application on a section of pavement that suffers from extensive studded tire wear. The purpose of the trial section is to determine if PPC is a possible repair strategy for this type of pavement d...

  15. Image Understanding Using Overlays

    Science.gov (United States)

    1980-05-31

    Codes from Quadtrees." TR-732, February 19 79. 29. Ann Scher, Flavio R. D. Velasco, and Azriel Rosenfeld, "Some New Image Smoothing Techniques...Techniques for Color Images." TR-748, April 1979. 35. Flavio R. D. Velasco, "Thresholding Using the Isodata Clustering Algorithm." TR-751, March 1979

  16. Declarative Networking

    CERN Document Server

    Loo, Boon Thau

    2012-01-01

    Declarative Networking is a programming methodology that enables developers to concisely specify network protocols and services, which are directly compiled to a dataflow framework that executes the specifications. Declarative networking proposes the use of a declarative query language for specifying and implementing network protocols, and employs a dataflow framework at runtime for communication and maintenance of network state. The primary goal of declarative networking is to greatly simplify the process of specifying, implementing, deploying and evolving a network design. In addition, decla

  17. Global multi-layer network of human mobility.

    Science.gov (United States)

    Belyi, Alexander; Bojic, Iva; Sobolevsky, Stanislav; Sitko, Izabela; Hawelka, Bartosz; Rudikova, Lada; Kurbatski, Alexander; Ratti, Carlo

    2017-07-03

    Recent availability of geo-localized data capturing individual human activity together with the statistical data on international migration opened up unprecedented opportunities for a study on global mobility. In this paper, we consider it from the perspective of a multi-layer complex network, built using a combination of three datasets: Twitter, Flickr and official migration data. Those datasets provide different, but equally important insights on the global mobility - while the first two highlight short-term visits of people from one country to another, the last one - migration - shows the long-term mobility perspective, when people relocate for good. The main purpose of the paper is to emphasize importance of this multi-layer approach capturing both aspects of human mobility at the same time. On the one hand, we show that although the general properties of different layers of the global mobility network are similar, there are important quantitative differences among them. On the other hand, we demonstrate that consideration of mobility from a multi-layer perspective can reveal important global spatial patterns in a way more consistent with those observed in other available relevant sources of international connections, in comparison to the spatial structure inferred from each network layer taken separately.

  18. Enumeration of sublethally injured Escherichia coli O157:H7 ATCC 43895 and Escherichia coli strain B-41560 using selective agar overlays versus commercial methods.

    Science.gov (United States)

    Smith, Amanda R; Ellison, Alysha L; Robinson, Amanda L; Drake, Maryanne; McDowell, Susan A; Mitchell, James K; Gerard, Patrick D; Heckler, Rachel A; McKillip, John L

    2013-04-01

    Quality control procedures during food processing may involve direct inoculation of food samples onto appropriate selective media for subsequent enumeration. However, sublethally injured bacteria often fail to grow, enabling them to evade detection and intervention measures and ultimately threaten the health of consumers. This study compares traditional selective and nonselective agar-based overlays versus two commercial systems (Petrifilm and Easygel) for recovery of injured E. coli B-41560 and O157:H7 strains. Bacteria were propagated in tryptic soy broth (TSB), ground beef slurry, and infant milk formula to a density of 10(6) to 10(8) CFU/ml and then were stressed for 6 min either in lactic acid (pH 4.5) or heat shocked for 3 min at 60°C. Samples were pour plated in basal layers of either tryptic soy agar (TSA), sorbitol MacConkey agar (SMAC), or violet red bile agar (VRB) and were resuscitated for 4 h prior to addition of agar overlays. Other stressed bacteria were plated directly onto Petrifilm and Easygel. Results indicate that selective and nonselective agar overlays recovered significantly higher numbers (greater than 1 log) of acid- and heat-injured E. coli O157:H7 from TSB, ground beef, and infant milk formula compared with direct plating onto selective media, Petrifilm, or Easygel, while no significant differences among these media combinations were observed for stressed E. coli B-41560. Nonstressed bacteria from TSB and ground beef were also recovered at densities significantly higher in nonselective TSA-TSA and in VRB-VRB and SMAC-SMAC compared with Petrifilm and Easygel. These data underscore the need to implement food safety measures that address sublethally injured pathogens such as E. coli O157:H7 in order to avoid underestimation of true densities for target pathogens.

  19. A bi-overlayer type plasmonic photocatalyst consisting of mesoporous Au/TiO2 and CuO/SnO2 films separately coated on FTO.

    Science.gov (United States)

    Naya, Shin-ichi; Kume, Takahiro; Okumura, Nozomi; Tada, Hiroaki

    2015-07-21

    The principal purpose of this study is to present a new design for preparing highly active immobilized gold nanoparticle-based plasmonic photocatalysts. Gold nanoparticles were loaded on rutile TiO2 particles with a mean size of 80 nm (Au/TiO2) by the deposition precipitation method. The surface of SnO2 particles with a mean size of 100 nm was modified by copper(ii) oxide clusters (CuO/SnO2) with the loading amount (Γ/Cu ions nm(-2)) precisely controlled by the chemisorption-calcination cycle technique. Two mesoporous overlayers of Au/TiO2 and CuO/SnO2 were coated side by side on glass substrates with a fluorine-doped tin oxide film (FTO) using the doctor blade method (Au/mp-TiO2|FTO|CuO/mp-SnO2). As test reactions for assessing the visible-light activity, we carried out gas-phase decomposition of acetaldehyde and liquid-phase oxidation of alcohol. In each reaction, this bi-overlayer type catalyst shows a high level of visible-light activity much exceeding those of Au/TiO2 particles and a Au/mp-TiO2|FTO mono-overlayer type catalyst [J. Phys. Chem. C, 2014, 118, 26887]. To confirm the origin of the striking visible-light activity, we studied the electrocatalytic activity of CuO/mp-SnO2|FTO electrodes for the oxygen reduction reaction (ORR). Both the visible-light activity of Au/mp-TiO2|FTO|CuO/mp-SnO2 and the electrocatalytic activity of CuO/mp-SnO2|FTO for ORR strongly depend on the Γ value. A good positive correlation has been found between the visible-light activities and the electrocatalytic activity for ORR. The striking activity of the present bi-overlayer type catalyst can be attributed to the efficient and long-range charge separation by the vectorial electron transport (Au(oxidation sites) → TiO2→ FTO, SnO2→ CuO(reduction sites)) and the excellent electrocatalytic activity of the CuO clusters.

  20. ISP-Friendly Data Scheduling by Advanced Locality-Aware Network Coding for P2P Distribution Cloud

    Directory of Open Access Journals (Sweden)

    Yanjun Li

    2014-01-01

    Full Text Available Peer-to-peer (P2P file distribution imposes increasingly heavy traffic burden on the Internet service providers (ISPs. The vast volume of traffic pushes up ISPs’ costs in routing and investment and degrades their networks performance. Building ISP-friendly P2P is therefore of critical importance for ISPs and P2P services. So far most efforts in this area focused on improving the locality-awareness of P2P applications, for example, to construct overlay networks with better knowledge of the underlying network topology. There is, however, growing recognition that data scheduling algorithms also play an effective role in P2P traffic reduction. In this paper, we introduce the advanced locality-aware network coding (ALANC for P2P file distribution. This data scheduling algorithm completely avoids the transmission of linearly dependent data blocks, which is a notable problem of previous network coding algorithms. Our simulation results show that, in comparison to other algorithms, ALANC not only significantly reduces interdomain P2P traffic, but also remarkably improves both the application-level performance (for P2P services and the network-level performance (for ISP networks. For example, ALANC is 30% faster in distributing data blocks and it reduces the average traffic load on the underlying links by 40%. We show that ALANC holds the above gains when the tit-for-tat incentive mechanism is introduced or the overlay topology changes dynamically.

  1. On Using Home Networks and Cloud Computing for a Future Internet of Things

    Science.gov (United States)

    Niedermayer, Heiko; Holz, Ralph; Pahl, Marc-Oliver; Carle, Georg

    In this position paper we state four requirements for a Future Internet and sketch our initial concept. The requirements: (1) more comfort, (2) integration of home networks, (3) resources like service clouds in the network, and (4) access anywhere on any machine. Future Internet needs future quality and future comfort. There need to be new possiblities for everyone. Our focus is on higher layers and related to the many overlay proposals. We consider them to run on top of a basic Future Internet core. A new user experience means to include all user devices. Home networks and services should be a fundamental part of the Future Internet. Home networks extend access and allow interaction with the environment. Cloud Computing can provide reliable resources beyond local boundaries. For access anywhere, we also need secure storage for data and profiles in the network, in particular for access with non-personal devices (Internet terminal, ticket machine, ...).

  2. The world network of scientific collaborations between cities: domestic or international dynamics?

    Energy Technology Data Exchange (ETDEWEB)

    Maisonobe, M.; Eckert, D.; Grossetti, M.; Jégou, L.; Milard, B.

    2016-07-01

    Earlier publication (Grossetti et al., 2014) has established that we are attending a decreasing concentration of scientific activities within “world-cities”. Given that more and more cities and countries are contributing to the world production of knowledge, this article analyzes the evolution of the world network of collaborations both at the domestic and international levels during the 2000s. Using data from the Science Citation Index Expanded, scientific authors’ addresses are geo-localized and grouped by urban areas. Our data suggests that interurban collaborations within countries have increased together with international linkages. In most countries, domestic collaborations have increased faster than international collaborations. Even among the top collaborating cities, sometimes referred to as “world cities”, the share of domestic collaborations is gaining momentum. Our results suggest that, contrary to common beliefs about the globalization process, national systems of research have been strengthening during the 2000s. (Author)

  3. The Deep Impact Network Experiment Operations Center

    Science.gov (United States)

    Torgerson, J. Leigh; Clare, Loren; Wang, Shin-Ywan

    2009-01-01

    Delay/Disruption Tolerant Networking (DTN) promises solutions in solving space communications challenges arising from disconnections as orbiters lose line-of-sight with landers, long propagation delays over interplanetary links, and other phenomena. DTN has been identified as the basis for the future NASA space communications network backbone, and international standardization is progressing through both the Consultative Committee for Space Data Systems (CCSDS) and the Internet Engineering Task Force (IETF). JPL has developed an implementation of the DTN architecture, called the Interplanetary Overlay Network (ION). ION is specifically implemented for space use, including design for use in a real-time operating system environment and high processing efficiency. In order to raise the Technology Readiness Level of ION, the first deep space flight demonstration of DTN is underway, using the Deep Impact (DI) spacecraft. Called the Deep Impact Network (DINET), operations are planned for Fall 2008. An essential component of the DINET project is the Experiment Operations Center (EOC), which will generate and receive the test communications traffic as well as "out-of-DTN band" command and control of the DTN experiment, store DTN flight test information in a database, provide display systems for monitoring DTN operations status and statistics (e.g., bundle throughput), and support query and analyses of the data collected. This paper describes the DINET EOC and its value in the DTN flight experiment and potential for further DTN testing.

  4. The network researchers' network

    DEFF Research Database (Denmark)

    Henneberg, Stephan C.; Jiang, Zhizhong; Naudé, Peter

    2009-01-01

    The Industrial Marketing and Purchasing (IMP) Group is a network of academic researchers working in the area of business-to-business marketing. The group meets every year to discuss and exchange ideas, with a conference having been held every year since 1984 (there was no meeting in 1987). In thi......The Industrial Marketing and Purchasing (IMP) Group is a network of academic researchers working in the area of business-to-business marketing. The group meets every year to discuss and exchange ideas, with a conference having been held every year since 1984 (there was no meeting in 1987......). In this paper, based upon the papers presented at the 22 conferences held to date, we undertake a Social Network Analysis in order to examine the degree of co-publishing that has taken place between this group of researchers. We identify the different components in this database, and examine the large main...

  5. Application of support vector machine to three-dimensional shape-based virtual screening using comprehensive three-dimensional molecular shape overlay with known inhibitors.

    Science.gov (United States)

    Sato, Tomohiro; Yuki, Hitomi; Takaya, Daisuke; Sasaki, Shunta; Tanaka, Akiko; Honma, Teruki

    2012-04-23

    In this study, machine learning using support vector machine was combined with three-dimensional (3D) molecular shape overlay, to improve the screening efficiency. Since the 3D molecular shape overlay does not use fingerprints or descriptors to compare two compounds, unlike 2D similarity methods, the application of machine learning to a 3D shape-based method has not been extensively investigated. The 3D similarity profile of a compound is defined as the array of 3D shape similarities with multiple known active compounds of the target protein and is used as the explanatory variable of support vector machine. As the measures of 3D shape similarity for our new prediction models, the prediction performances of the 3D shape similarity metrics implemented in ROCS, such as ShapeTanimoto and ScaledColor, were validated, using the known inhibitors of 15 target proteins derived from the ChEMBL database. The learning models based on the 3D similarity profiles stably outperformed the original ROCS when more than 10 known inhibitors were available as the queries. The results demonstrated the advantages of combining machine learning with the 3D similarity profile to process the 3D shape information of plural active compounds.

  6. A Graphic Overlay Method for Selection of Osteotomy Site in Chronic Radial Head Dislocation: An Evaluation of 3D-printed Bone Models.

    Science.gov (United States)

    Kim, Hui Taek; Ahn, Tae Young; Jang, Jae Hoon; Kim, Kang Hee; Lee, Sung Jae; Jung, Duk Young

    2017-03-01

    Three-dimensional (3D) computed tomography imaging is now being used to generate 3D models for planning orthopaedic surgery, but the process remains time consuming and expensive. For chronic radial head dislocation, we have designed a graphic overlay approach that employs selected 3D computer images and widely available software to simplify the process of osteotomy site selection. We studied 5 patients (2 traumatic and 3 congenital) with unilateral radial head dislocation. These patients were treated with surgery based on traditional radiographs, but they also had full sets of 3D CT imaging done both before and after their surgery: these 3D CT images form the basis for this study. From the 3D CT images, each patient generated 3 sets of 3D-printed bone models: 2 copies of the preoperative condition, and 1 copy of the postoperative condition. One set of the preoperative models was then actually osteotomized and fixed in the manner suggested by our graphic technique. Arcs of rotation of the 3 sets of 3D-printed bone models were then compared. Arcs of rotation of the 3 groups of bone models were significantly different, with the models osteotomized accordingly to our graphic technique having the widest arcs. For chronic radial head dislocation, our graphic overlay approach simplifies the selection of the osteotomy site(s). Three-dimensional-printed bone models suggest that this approach could improve range of motion of the forearm in actual surgical practice. Level IV-therapeutic study.

  7. Comparative stress distribution of implant-retained mandibular ball-supported and bar-supported overlay dentures: a finite element analysis.

    Science.gov (United States)

    Vafaei, Fariborz; Khoshhal, Masoumeh; Bayat-Movahed, Saeed; Ahangary, Ahmad Hassan; Firooz, Farnaz; Izady, Alireza; Rakhshan, Vahid

    2011-08-01

    Implant-retained mandibular ball-supported and bar-supported overlay dentures are the two most common treatment options for the edentulous mandible. The superior option in terms of strain distribution should be determined. The three-dimensional model of mandible (based on computerized tomography scan) and its overlying implant-retained bar-supported and ball-supported overlay dentures were simulated using SolidWorks, NURBS, and ANSYS Workbench. Loads A (60 N) and B (60 N) were exerted, respectively, in protrusive and laterotrusive motions, on second molar mesial, first molar mesial, and first premolar. The strain distribution patterns were assessed on (1) implant tissue, (2) first implant-bone, and (3) second implant-bone interfaces. Protrusive: Strain was mostly detected in the apical of the fixtures and least in the cervical when bar design was used. On the nonworking side, however, strain was higher in the cervical and lower in the apical compared with the working side implant. Laterotrusive: The strain values were closely similar in the two designs. It seems that both designs are acceptable in terms of stress distribution, although a superior pattern is associated with the application of bar design in protrusive motion.

  8. Network cosmology.

    Science.gov (United States)

    Krioukov, Dmitri; Kitsak, Maksim; Sinkovits, Robert S; Rideout, David; Meyer, David; Boguñá, Marián

    2012-01-01

    Prediction and control of the dynamics of complex networks is a central problem in network science. Structural and dynamical similarities of different real networks suggest that some universal laws might accurately describe the dynamics of these networks, albeit the nature and common origin of such laws remain elusive. Here we show that the causal network representing the large-scale structure of spacetime in our accelerating universe is a power-law graph with strong clustering, similar to many complex networks such as the Internet, social, or biological networks. We prove that this structural similarity is a consequence of the asymptotic equivalence between the large-scale growth dynamics of complex networks and causal networks. This equivalence suggests that unexpectedly similar laws govern the dynamics of complex networks and spacetime in the universe, with implications to network science and cosmology.

  9. Network Cosmology

    Science.gov (United States)

    Krioukov, Dmitri; Kitsak, Maksim; Sinkovits, Robert S.; Rideout, David; Meyer, David; Boguñá, Marián

    2012-01-01

    Prediction and control of the dynamics of complex networks is a central problem in network science. Structural and dynamical similarities of different real networks suggest that some universal laws might accurately describe the dynamics of these networks, albeit the nature and common origin of such laws remain elusive. Here we show that the causal network representing the large-scale structure of spacetime in our accelerating universe is a power-law graph with strong clustering, similar to many complex networks such as the Internet, social, or biological networks. We prove that this structural similarity is a consequence of the asymptotic equivalence between the large-scale growth dynamics of complex networks and causal networks. This equivalence suggests that unexpectedly similar laws govern the dynamics of complex networks and spacetime in the universe, with implications to network science and cosmology. PMID:23162688

  10. Forecasting influenza-like illness dynamics for military populations using neural networks and social media.

    Directory of Open Access Journals (Sweden)

    Svitlana Volkova

    , signals from social media can be potentially used to accurately forecast ILI dynamics for the regions where ILI historical data is not available. (d Neural network models learned from combined ILI and social media signals significantly outperform models that rely solely on ILI historical data, which adds to a great potential of alternative public sources for ILI dynamics prediction. (e Location-specific models outperform previously used location-independent models e.g., U.S. only. (f Prediction results significantly vary across geolocations depending on the amount of social media data available and ILI activity patterns. (g Model performance improves with more tweets available per geo-location e.g., the error gets lower and the Pearson score gets higher for locations with more tweets.

  11. Forecasting influenza-like illness dynamics for military populations using neural networks and social media.

    Science.gov (United States)

    Volkova, Svitlana; Ayton, Ellyn; Porterfield, Katherine; Corley, Courtney D

    2017-01-01

    social media can be potentially used to accurately forecast ILI dynamics for the regions where ILI historical data is not available. (d) Neural network models learned from combined ILI and social media signals significantly outperform models that rely solely on ILI historical data, which adds to a great potential of alternative public sources for ILI dynamics prediction. (e) Location-specific models outperform previously used location-independent models e.g., U.S. only. (f) Prediction results significantly vary across geolocations depending on the amount of social media data available and ILI activity patterns. (g) Model performance improves with more tweets available per geo-location e.g., the error gets lower and the Pearson score gets higher for locations with more tweets.

  12. Net-centric Controlled Distributed Stand-in-Jamming using UAVs-Transmission Losses and Range Limitations Due to Geo-localization Problem Over Turkish Geography

    Science.gov (United States)

    2012-09-01

    Jamming UAS Unmanned Aerial System UAV Unmanned Aerial Vehicle WSN Wireless Sensor Network xv ACKNOWLEDGMENTS I would love to express my...discussion to military use of the spectrum, and thus the very first definition implies the military use of EM and directed energy . The success of EW...the modern battle management concept. The definition of EW addresses any military action involving the use of electromagnetic and directed energy to

  13. Telecommunication networks

    CERN Document Server

    Iannone, Eugenio

    2011-01-01

    Many argue that telecommunications network infrastructure is the most impressive and important technology ever developed. Analyzing the telecom market's constantly evolving trends, research directions, infrastructure, and vital needs, Telecommunication Networks responds with revolutionized engineering strategies to optimize network construction. Omnipresent in society, telecom networks integrate a wide range of technologies. These include quantum field theory for the study of optical amplifiers, software architectures for network control, abstract algebra required to design error correction co

  14. Morphological and chemical stability of silicon nanostructures and their molecular overlayers under physiological conditions: towards long-term implantable nanoelectronic biosensors.

    Science.gov (United States)

    Peled, Anna; Pevzner, Alexander; Peretz Soroka, Hagit; Patolsky, Fernando

    2014-03-09

    The detection of biological and chemical species is of key importance to numerous areas of medical and life sciences. Therefore, a great interest exists in developing new, rapid, miniature, biocompatible and highly sensitive sensors, capable to operate under physiological conditions and displaying long-term stabilities (e.g. in-body implantable sensors). Silicon nanostructures, nanowires and nanotubes, have been extensively explored as building blocks for the creation of improved electrical biosensing devices, by virtue of their remarkably high surface-to-volume ratios, and have shown exceptional sensitivity for the real time label-free detection of molecular species adsorbed on their surfaces, down to the sensitivity of single molecules.Yet, till this date, almost no rigorous studies have been performed on the temporal morphological stability of these nanostructures, and their resulting electrical devices, under physiological conditions (e.g. serum, blood), as well as on the chemical stability of the molecular recognition over-layers covering these structures. Here, we present systematic time-resolved results on the morphological stability of bare Si nanowire building blocks, as well on the chemical stability of siloxane-based molecular over-layers, under physiological conditions. Furthermore, in order to overcome the observed short-term morpho-chemical instabilities, we present on the chemical passivation of the Si nanostructures by thin metal oxide nanoshells, in the range of 3-10 nm. The thickness of the metal oxide layer influences on the resulting electrical sensitivity of the fabricated FETs (field effect transistors), with an optimum thickness of 3-4 nm. The core-shell structures display remarkable long-term morphological stability, preventing both, the chemical hydrolytic dissolution of the silicon under-structure and the concomitant loss of the siloxane-based chemical over-layers, for periods of at least several months. Electrical devices constructed

  15. Assignment of the absolute configuration of hepatoprotective highly oxygenated triterpenoids using X-ray, ECD, NMR J-based configurational analysis and HSQC overlay experiments.

    Science.gov (United States)

    Wang, Xiaojuan; Liu, Jiabao; Pandey, Pankaj; Chen, Jiabao; Fronczek, Frank R; Parnham, Stuart; Qi, Xinzhu; Doerksen, Robert J; Ferreira, Daneel; Sun, Hua; Li, Shuai; Hamann, Mark T

    2017-12-01

    The plants of the genus Kadsura are widely distributed in China, South Korea, and Japan. Their roots and stems are traditionally used to treat blood diseases and pain. The main bioactive constituents of Kadsura longipedunculata comprise highly oxygenated triterpenoids. Schiartane-type nortriterpenoids showed anti-HIV, anti-HBV, and cytotoxic bioactivities. For such compounds, the absolute configuration influences the bioactivities, and hence its unambiguous determination is essential. In this work, the absolute configurations of three highly oxygenated schiartane-type nortriterpenoids were unequivocally assigned using X-ray, ECD, and J-based configuration analysis and HSQC overlay data. The ethanol extract of Kadsura longipedunculata Finet et Gagnep was purified by column chromatography using silica, Sephadex LH-20, and ODS as substrates. To help assign the absolute configuration of schiartane-type nortriterpenoids, X-ray diffraction analysis, ECD experiment compared to ab initio computed data, DP4+ analysis, HSQC overlay, NOESY, and J-based configuration analysis were carried out. Hetero- and homo-nuclear coupling constants were extracted from HETLOC experiments. Three new highly oxygenated triterpenoids, micrandilactone I (1), micrandilactone J (2), and 22,23-di-epi-micrandilactone J (3) were isolated. Their 2D structures were solved using NMR and HRESIMS data and their absolute configurations were elucidated using X-ray diffraction analysis, ECD experimental results compared to ab initio computed spectra, HSQC overlay, DP4+, NOESY, and J-based configuration analysis. Micrandilactone I (1) and 22,23-di-epi-micrandilactone J (3) showed moderate hepatoprotective activity against APAP-induced toxicity in HepG2 cells with cell survival rates of 53.0 and 50.2%, respectively, at 10μM (bicyclol, 49.0%), while micrandilactone J (2) was inactive. This is the first comprehensive stereochemical assignment of a non-crystalline schiartane-type nortriterpenoid like 3. This

  16. Interconnected networks

    CERN Document Server

    2016-01-01

    This volume provides an introduction to and overview of the emerging field of interconnected networks which include multi layer or multiplex networks, as well as networks of networks. Such networks present structural and dynamical features quite different from those observed in isolated networks. The presence of links between different networks or layers of a network typically alters the way such interconnected networks behave – understanding the role of interconnecting links is therefore a crucial step towards a more accurate description of real-world systems. While examples of such dissimilar properties are becoming more abundant – for example regarding diffusion, robustness and competition – the root of such differences remains to be elucidated. Each chapter in this topical collection is self-contained and can be read on its own, thus making it also suitable as reference for experienced researchers wishing to focus on a particular topic.

  17. COSIM: A Finite-Difference Computer Model to Predict Ternary Concentration Profiles Associated With Oxidation and Interdiffusion of Overlay-Coated Substrates

    Science.gov (United States)

    Nesbitt, James A.

    2001-01-01

    A finite-difference computer program (COSIM) has been written which models the one-dimensional, diffusional transport associated with high-temperature oxidation and interdiffusion of overlay-coated substrates. The program predicts concentration profiles for up to three elements in the coating and substrate after various oxidation exposures. Surface recession due to solute loss is also predicted. Ternary cross terms and concentration-dependent diffusion coefficients are taken into account. The program also incorporates a previously-developed oxide growth and spalling model to simulate either isothermal or cyclic oxidation exposures. In addition to predicting concentration profiles after various oxidation exposures, the program can also be used to predict coating life based on a concentration dependent failure criterion (e.g., surface solute content drops to 2%). The computer code is written in FORTRAN and employs numerous subroutines to make the program flexible and easily modifiable to other coating oxidation problems.

  18. Network maintenance

    CERN Multimedia

    IT Department

    2009-01-01

    A site wide network maintenance has been scheduled for Saturday 28 February. Most of the network devices of the General Purpose network will be upgraded to a newer software version, in order to improve our network monitoring capabilities. This will result in a series of short (2-5 minutes) random interruptions everywhere on the CERN sites along this day. This upgrade will not affect: the Computer centre itself, building 613, the Technical Network and the LHC experiments dedicated networks at the pits. Should you need more details on this intervention, please contact Netops by phone 74927 or email mailto:Netops@cern.ch. IT/CS Group

  19. Network maintenance

    CERN Multimedia

    GS Department

    2009-01-01

    A site-wide network maintenance operation has been scheduled for Saturday 28 February. Most of the network devices of the general purpose network will be upgraded to a newer software version, in order to improve our network monitoring capabilities. This will result in a series of short (2-5 minutes) random interruptions everywhere on the CERN sites throughout the day. This upgrade will not affect the Computer Centre itself, Building 613, the Technical Network and the LHC experiments, dedicated networks at the pits. For further details of this intervention, please contact Netops by phone 74927 or e-mail mailto:Netops@cern.ch. IT/CS Group

  20. Evolution of the SrTiO{sub 3} surface electronic state as a function of LaAlO{sub 3} overlayer thickness

    Energy Technology Data Exchange (ETDEWEB)

    Plumb, N.C.; Kobayashi, M. [Swiss Light Source, Paul Scherrer Insitut, CH-5232 Villigen PSI (Switzerland); Salluzzo, M. [CNR-SPIN, Complesso Universitario Monte S. Angelo, Via Cinthia, I-80126 Napoli (Italy); Razzoli, E.; Matt, C.E.; Strocov, V.N.; Zhou, K.J.; Shi, M. [Swiss Light Source, Paul Scherrer Insitut, CH-5232 Villigen PSI (Switzerland); Mesot, J. [Paul Scherrer Institut, CH-5232 Villigen PSI (Switzerland); Institut de la Matiere Complexe, EPF Lausanne, CH-1015 Lausanne (Switzerland); Laboratory for Solid State Physics, ETH Zürich, CH-8093 Zürich (Switzerland); Schmitt, T. [Swiss Light Source, Paul Scherrer Insitut, CH-5232 Villigen PSI (Switzerland); Patthey, L. [Swiss Light Source, Paul Scherrer Insitut, CH-5232 Villigen PSI (Switzerland); SwissFEL, Paul Scherrer Institut, CH-5232 Villigen PSI (Switzerland); Radović, M., E-mail: milan.radovic@psi.ch [Swiss Light Source, Paul Scherrer Insitut, CH-5232 Villigen PSI (Switzerland); Institut de la Matiere Complexe, EPF Lausanne, CH-1015 Lausanne (Switzerland); SwissFEL, Paul Scherrer Institut, CH-5232 Villigen PSI (Switzerland)

    2017-08-01

    Highlights: • The close similarities in the electronic structures of the metallic bare surface of STO and the buried interfaces (LAO/STO). • The similar spectroscopic responses of these systems to photon irradiation. • The emergence of 2 × 1 structural ordering in sufficiently thick LAO/STO interfaces. - Abstract: The novel electronic properties emerging at interfaces between transition metal oxides, and in particular the discovery of conductivity in heterostructures composed of LaAlO{sub 3} (LAO) and SrTiO{sub 3} (STO) band insulators, have generated new challenges and opportunities in condensed matter physics. Although the interface conductivity is stabilized when LAO matches or exceeds a critical thickness of 4 unit cells (uc), other phenomena such as a universal metallic state found on the bare surface of STO single crystals and persistent photon-triggered conductivity in otherwise insulating STO-based interfaces raise important questions about the role of the LAO overlayer and the possible relations between vacuum/STO and LAO/STO interfaces. Here, using angle-resolved photoemission spectroscopy (ARPES) on in situ prepared samples complemented by resonant inelastic X-ray scattering (RIXS), we study how the metallic STO surface state evolves during the growth of a crystalline LAO overlayer. In all the studied samples, the character of the conduction bands, their carrier densities, the Ti{sup 3+} crystal field, and the response to photon irradiation bear strong similarities. Nevertheless, we report here that studied LAO/STO interfaces exhibit an instability toward an apparent 2 × 1 folding of the Fermi surface at and above a 4 uc thickness threshold, which distinguishes these heterostructures from bare STO and sub-critical-thickness LAO/STO.

  1. The effect of a fiber reinforced cavity configuration on load bearing capacity and failure mode of endodontically treated molars restored with CAD/CAM resin composite overlay restorations.

    Science.gov (United States)

    Rocca, G T; Saratti, C M; Cattani-Lorente, M; Feilzer, A J; Scherrer, S; Krejci, I

    2015-09-01

    To evaluate the fracture strength and the mode of failure of endodontically treated molars restored with CAD/CAM overlays with fiber reinforced composite build-up of the pulp chamber. 40 Devitalized molars were cut over the CEJ and divided into five groups (n=8). The pulp chamber area was filled with: group 0 (control), no resin build-up; group 1, hybrid composite build-up (G-aenial posterior, GC); group 2, as in group 1 but covered with 3 nets of bi-directional E-glass fibers (EverStickNET, Stick Tech Ltd.); group 3, a FRC resin (EverX posterior, GC); group 4, as in group 3 but covered by the bi-directional fibers. The crowns were restored with CAD-CAM composite restorations (Lava Ultimate, 3M ESPE). Maximum fracture loads were recorded in Newton and data were analyzed using Kruskal-Wallis test (p0.05). All specimens fractured in a catastrophic way, under the CEJ. The main crack evolved in the corono-apical direction. In groups 2 and 4 secondary fracture paths with apico-coronal direction were detected close to the bi-directional fibers' layer. For the restoration of endodontically treated molars, the incorporation of FRCs did not influence the load-bearing capacity of the tooth-restoration complex. The SEM analysis showed a low ability of the bi-directional fibers net in deviating the fracture but this effect was not sufficient to lead more favorable fracture patterns, over the CEJ. The use of FRCs to reinforce the "core" of devitalized molars against vertical fractures under static loads seems useless when the thickness of the CAD/CAM composite overlay restoration is high. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. Catalytic activity and stability of nanometic Rh overlayers prepared by pulsed arc-plasma deposition and r.f. magnetron-sputtering

    Science.gov (United States)

    Misumi, Satoshi; Matsumoto, Akinori; Yoshida, Hiroshi; Sato, Tetsuya; Machida, Masato

    2018-01-01

    50 μm-thick Fe-Cr-Al metal foils covered by 7 nm-thick Rh overlayers were prepared by pulsed arc-plasma (AP) and r.f. magnetron sputtering technique to compare their catalytic activities. As-prepared metal foil catalysts were wrapped into a honeycomb structure with a density of 900 cells per square inches and the stoichiometric NO-CO-C3H6-O2 reaction was performed at space velocity of 1.2 × 105 h-1. During temperature ramp at 10 °C min-1, honeycomb catalysts showed steep light-off of NO, CO, and C3H6 at above 200 °C and their conversions soon reached to almost 100%. Both catalysts exhibited high turnover frequencies close to or more than 50-fold greater compared with those for a reference Rh/ZrO2 powder-coated cordierite honeycomb prepared using a conventional slurry coating. When the temperature ramping was repeated, however, the catalytic activity was decreased to the different extent depending on the preparation procedure. Significant deactivation occurred only when prepared by sputtering, whereas the sample prepared by AP showed no signs of deactivation. The deactivation is associated with the formation of passivation layers consisting of Fe, Cr, and Al oxides, which covered the surface and decreased the surface concentration of Rh. The Rh overlayer formed by AP was found to be thermally stable because of the strong adhesion to the metal foil surface, compared to the sample prepared by sputtering.

  3. Dielectric over-layer assisted graphene, its oxide and MoS2-based fibre optic sensor with high field enhancement

    Science.gov (United States)

    Nayak, Jeeban Kumar; Maharana, Pradeep Kumar; Jha, Rajan

    2017-10-01

    A high-index fibre-core-based surface plasmon resonance (SPR) sensor using 2D materials such as graphene, graphene oxide (GO) and molybdenum disulphide (MoS2) on a silicon (Si) over-layer in visible and near infrared is reported. Si was used on silver (Ag) followed by different 2D materials of appropriate thickness on a 600 µm core multimode fibre. Here Si is used to tune the resonance to a higher wavelength, and different 2D materials are used to enhance the performance as well as address the oxidation problem of Si. Moreover, a high-index chalcogenide core helps to decrease the full width at half maxima of the SPR spectra, hence increasing the detection accuracy of the sensor. Both the Ag and Si thickness are optimized, and the effects of different 2D materials on the performance of sensor are studied using the transfer matrix method in terms of electric field intensity, sensitivity, figure of merit (FOM) and resolution. We found that the percentage electric field enhancement for the Ag-Si-GO system is 4.65  ×  104 in the presence of GO. The GO-based sensor is found to have a sensitivity of 202.2 nm RIU-1 in comparison to the graphene based sensor with a sensitivity of 189.4 nm RIU-1. Moreover, the FOM values are found to be as high as 5.57 RIU-1 for GO, and 5.18 RIU-1 and 2.29 RIU-1 for the MoS2 and graphene respectively. We believe that the proposed 2D-material-based sensors will open a new window for the development of high-performance fibre biosensors by utilizing the biocompatibility aspect of different 2D materials along with its high electric field value in the presence of a dielectric over-layer.

  4. Effects of time-specific F-strain Mycoplasma gallisepticum inoculation overlays on prelay ts-11-strain M. gallisepticum vaccination on blood characteristics of commercial laying hens.

    Science.gov (United States)

    Peebles, E D; Vance, A M; Branton, S L; Collier, S D; Gerard, P D

    2009-05-01

    Two trials were conducted to determine the effects of a prelay ts-11-strain Mycoplasma gallisepticum (ts-11MG) vaccination alone or in combination with subsequent time-specific F-strain M. gallisepticum (FMG) inoculations on the blood characteristics of commercial laying hens. The following 4 treatments were utilized: 1) sham vaccination at 10 wk of age, 2) vaccination of ts-11MG at 10 wk, 3) ts-11MG at 10 wk overlaid by FMG inoculation at 22 wk, and 4) ts-11MG at 10 wk overlaid by FMG at 45 wk. Parameters measured in both trials were whole blood hematocrit, plasma protein, serum cholesterol, serum triglycerides, and serum calcium. No significant age x treatment interactions and no significant age or treatment main effects were observed for any of the blood parameters investigated, except for serum calcium. At wk 22, serum calcium concentrations were increased by vaccination with ts-11MG at 10 wk, and levels were further increased when the ts-11MG vaccination at 10 wk was overlaid by an FMG inoculation at 22 wk. These results suggest that ts-11MG vaccination at 10 wk of age alone or combined with F-strain inoculum overlays at either 22 or 45 wk may be used without any consequential effects on hematocrit or the lipid and protein levels in the blood of commercial layers. Because elevations in serum calcium were not associated with changes in hen performance, as reported in a previous companion article, it is further suggested that prelay ts-11MG vaccination before FMG inoculation overlays during lay may provide adequate protection against field strain M. gallisepticum infections while being innocuous to layer performance.

  5. Fe-Al Weld Overlay and High Velocity Oxy-Fuel Thermal Spray Coatings for Corrosion Protection of Waterwalls in Fossil Fired Plants with Low NOx Burners

    Energy Technology Data Exchange (ETDEWEB)

    Regina, J.R.

    2002-02-08

    Iron-aluminum-chromium coatings were investigated to determine the best candidates for coatings of boiler tubes in Low NOx fossil fueled power plants. Ten iron-aluminum-chromium weld claddings with aluminum concentrations up to 10wt% were tested in a variety of environments to evaluate their high temperature corrosion resistance. The weld overlay claddings also contained titanium additions to investigate any beneficial effects from these ternary and quaternary alloying additions. Several High-Velocity Oxy-Fuel (HVOF) thermal spray coatings with higher aluminum concentrations were investigated as well. Gaseous corrosion testing revealed that at least 10wt%Al is required for protection in the range of environments examined. Chromium additions were beneficial in all of the environments, but additions of titanium were beneficial only in sulfur rich atmospheres. Similar results were observed when weld claddings were in contact with corrosive slag while simultaneously, exposed to the corrosive environments. An aluminum concentration of 10wt% was required to prevent large amounts of corrosion to take place. Again chromium additions were beneficial with the greatest corrosion protection occurring for welds containing both 10wt%Al and 5wt%Cr. The exposed thermal spray coatings showed either significant cracking within the coating, considerable thickness loss, or corrosion products at the coating substrate interface. Therefore, the thermal spray coatings provided the substrate very little protection. Overall, it was concluded that of the coatings studied weld overlay coatings provide superior protection in these Low NOx environments; specifically, the ternary weld composition of 10wt%Al and 5wt%Cr provided the best corrosion protection in all of the environments tested.

  6. On the stability of copper overlayers on Au(1 1 1) and Au(1 0 0) electrodes under low potential conditions and in the presence on CO and CO2

    DEFF Research Database (Denmark)

    Schlaup, Christian Georg; Horch, Sebastian; Chorkendorff, Ib

    2015-01-01

    We have studied the stability of Cu overlayers on Au(1 1 1) and Au(1 0 0) electrodes under low potential conditions and in the presence of CO and CO2 by means of electrochemical STM (EC-STM). For preparation we utilized the well known underpotential deposition (UPD) of copper, which, depending...

  7. Network Ambivalence

    Directory of Open Access Journals (Sweden)

    Patrick Jagoda

    2015-08-01

    Full Text Available The language of networks now describes everything from the Internet to the economy to terrorist organizations. In distinction to a common view of networks as a universal, originary, or necessary form that promises to explain everything from neural structures to online traffic, this essay emphasizes the contingency of the network imaginary. Network form, in its role as our current cultural dominant, makes scarcely imaginable the possibility of an alternative or an outside uninflected by networks. If so many things and relationships are figured as networks, however, then what is not a network? If a network points towards particular logics and qualities of relation in our historical present, what others might we envision in the future? In  many ways, these questions are unanswerable from within the contemporary moment. Instead of seeking an avant-garde approach (to move beyond networks or opting out of networks (in some cases, to recover elements of pre-networked existence, this essay proposes a third orientation: one of ambivalence that operates as a mode of extreme presence. I propose the concept of "network aesthetics," which can be tracked across artistic media and cultural forms, as a model, style, and pedagogy for approaching interconnection in the twenty-first century. The following essay is excerpted from Network Ambivalence (Forthcoming from University of Chicago Press. 

  8. Jxta-Overlay : an interface for Efficient Peer Selection in P2P JXTA-based Systems

    OpenAIRE

    Xhafa, Fatos; Barolli, Leonard; Daradoumis Haralabus, Atanasi; Fernández Correa, Raúl; Caballé Llobet, Santi

    2008-01-01

    In this paper we address the problem of the efficient peer selection in P2P distributed platforms. To this end, we have developed a P2P distributed platform using Sun's JXTA technology, which is endowed with resource brokerage strategies to efficiently select peers using four selection models: (a) economic scheduling model; (b) priced-based model; (c) peer-priority selection model; and, (d) random selection model. Next, we have deployed the P2P platform in a real network using nodes of the Pl...

  9. A cloud-based forensics tracking scheme for online social network clients.

    Science.gov (United States)

    Lin, Feng-Yu; Huang, Chien-Cheng; Chang, Pei-Ying

    2015-10-01

    In recent years, with significant changes in the communication modes, most users are diverted to cloud-based applications, especially online social networks (OSNs), which applications are mostly hosted on the outside and available to criminals, enabling them to impede criminal investigations and intelligence gathering. In the virtual world, how the Law Enforcement Agency (LEA) identifies the "actual" identity of criminal suspects, and their geolocation in social networks, is a major challenge to current digital investigation. In view of this, this paper proposes a scheme, based on the concepts of IP location and network forensics, which aims to develop forensics tracking on OSNs. According to our empirical analysis, the proposed mechanism can instantly trace the "physical location" of a targeted service resource identifier (SRI), when the target client is using online social network applications (Facebook, Twitter, etc.), and can analyze the probable target client "identity" associatively. To the best of our knowledge, this is the first individualized location method and architecture developed and evaluated in OSNs. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  10. Network neuroscience.

    Science.gov (United States)

    Bassett, Danielle S; Sporns, Olaf

    2017-02-23

    Despite substantial recent progress, our understanding of the principles and mechanisms underlying complex brain function and cognition remains incomplete. Network neuroscience proposes to tackle these enduring challenges. Approaching brain structure and function from an explicitly integrative perspective, network neuroscience pursues new ways to map, record, analyze and model the elements and interactions of neurobiological systems. Two parallel trends drive the approach: the availability of new empirical tools to create comprehensive maps and record dynamic patterns among molecules, neurons, brain areas and social systems; and the theoretical framework and computational tools of modern network science. The convergence of empirical and computational advances opens new frontiers of scientific inquiry, including network dynamics, manipulation and control of brain networks, and integration of network processes across spatiotemporal domains. We review emerging trends in network neuroscience and attempt to chart a path toward a better understanding of the brain as a multiscale networked system.

  11. Organizational Networks

    DEFF Research Database (Denmark)

    Grande, Bård; Sørensen, Ole Henning

    1998-01-01

    The paper focuses on the concept of organizational networks. Four different uses of the concept of organizational network are identified and critically discussed. Special focus is placed on how information and communication technologies as communication mediators and cognitive pictures influence...

  12. Network workshop

    DEFF Research Database (Denmark)

    Bruun, Jesper; Evans, Robert Harry

    2014-01-01

    This paper describes the background for, realisation of and author reflections on a network workshop held at ESERA2013. As a new research area in science education, networks offer a unique opportunity to visualise and find patterns and relationships in complicated social or academic network data...... research community. With this workshop, participants were offered a way into network science based on authentic educational research data. The workshop was constructed as an inquiry lesson with emphasis on user autonomy. Learning activities had participants choose to work with one of two cases of networks...... network methodology in one’s research might supersede the perceived benefits of doing so. As a response to that problem, we argue that workshops can act as a road towards meaningful engagement with networks and highlight that network methodology promises new ways of interpreting data to answer questions...

  13. Social Networks

    OpenAIRE

    Martí, Joan; Zenou, Yves

    2009-01-01

    We survey the literature on social networks by putting together the economics, sociological and physics/applied mathematics approaches, showing their similarities and differences. We expose, in particular, the two main ways of modeling network formation. While the physics/applied mathematics approach is capable of reproducing most observed networks, it does not explain why they emerge. On the contrary, the economics approach is very precise in explaining why networks emerge but does a poor jo...

  14. Network Coding

    Indian Academy of Sciences (India)

    Network coding is a technique to increase the amount of information °ow in a network by mak- ing the key observation that information °ow is fundamentally different from commodity °ow. Whereas, under traditional methods of opera- tion of data networks, intermediate nodes are restricted to simply forwarding their incoming.

  15. Picoradio: Communication/Computation Piconodes for Sensor Networks

    National Research Council Canada - National Science Library

    Rabaey, Jan

    2003-01-01

    This project addressed the 'system-on-a-chip' implementation of a PicoNode, which can provide all the communication, computation, and geolocation functions necessary for an adaptive distributed sensor...

  16. Technical Network

    CERN Multimedia

    2007-01-01

    In order to optimise the management of the Technical Network (TN), to facilitate understanding of the purpose of devices connected to the TN and to improve security incident handling, the Technical Network Administrators and the CNIC WG have asked IT/CS to verify the "description" and "tag" fields of devices connected to the TN. Therefore, persons responsible for systems connected to the TN will receive e-mails from IT/CS asking them to add the corresponding information in the network database at "network-cern-ch". Thank you very much for your cooperation. The Technical Network Administrators & the CNIC WG

  17. Network science

    CERN Document Server

    Barabasi, Albert-Laszlo

    2016-01-01

    Networks are everywhere, from the Internet, to social networks, and the genetic networks that determine our biological existence. Illustrated throughout in full colour, this pioneering textbook, spanning a wide range of topics from physics to computer science, engineering, economics and the social sciences, introduces network science to an interdisciplinary audience. From the origins of the six degrees of separation to explaining why networks are robust to random failures, the author explores how viruses like Ebola and H1N1 spread, and why it is that our friends have more friends than we do. Using numerous real-world examples, this innovatively designed text includes clear delineation between undergraduate and graduate level material. The mathematical formulas and derivations are included within Advanced Topics sections, enabling use at a range of levels. Extensive online resources, including films and software for network analysis, make this a multifaceted companion for anyone with an interest in network sci...

  18. Vulnerability of network of networks

    Science.gov (United States)

    Havlin, S.; Kenett, D. Y.; Bashan, A.; Gao, J.; Stanley, H. E.

    2014-10-01

    Our dependence on networks - be they infrastructure, economic, social or others - leaves us prone to crises caused by the vulnerabilities of these networks. There is a great need to develop new methods to protect infrastructure networks and prevent cascade of failures (especially in cases of coupled networks). Terrorist attacks on transportation networks have traumatized modern societies. With a single blast, it has become possible to paralyze airline traffic, electric power supply, ground transportation or Internet communication. How, and at which cost can one restructure the network such that it will become more robust against malicious attacks? The gradual increase in attacks on the networks society depends on - Internet, mobile phone, transportation, air travel, banking, etc. - emphasize the need to develop new strategies to protect and defend these crucial networks of communication and infrastructure networks. One example is the threat of liquid explosives a few years ago, which completely shut down air travel for days, and has created extreme changes in regulations. Such threats and dangers warrant the need for new tools and strategies to defend critical infrastructure. In this paper we review recent advances in the theoretical understanding of the vulnerabilities of interdependent networks with and without spatial embedding, attack strategies and their affect on such networks of networks as well as recently developed strategies to optimize and repair failures caused by such attacks.

  19. Presentation of the Multimédia Game "Geolover" Concept, to Educational Enchancement of the Geolocical Heritage of the Following Regions: "Ilha do Fogo" (Cabo-Verde), Seridó (Brasil), Sabugal (Portugal) and Açores (Portugal)

    Science.gov (United States)

    Cabral, João; Gomes, Ana; Alfama, Vera; Oliveira, Sirlene; Pinharandas, Carlos; Fonseca, Pedro; Campos, José; Nobre, José

    2013-04-01

    "Geolover" - Presentation of the multimédia game concept, to educational enchancement of the geolocical heritage of the following regions: : "Ilha do Fogo" (Cabo-Verde), Seridó (Brasil), Sabugal and Açores (Portugal). "Geolover" is a multitouch game, played by four players simultaneously, identified by 4 mascots and using as sceneries, the four regions landscapes, aimed to the young people with ages between 8 and 12 years old. The main objective is value the geological heritage of the Ilha do Fogo (Cabo Verde), Seridó in State of Rio Grande do Norte (Brasil) , Sabugal in Beira Alta province (Portugal) and Arquipélago dos Açores (Portuguese autonomous region). These regions have a great geological heritage like volcanology, plutonic rocks, sedimentar formations, metamorphic, paleontologic, mineralogic, geomorphologic, hydric and mining resources. Such heritage is being used in the different regions has base of studies to senior scientists and were used to great scientific researches. The diversified and distinguished cultural heritage of these four regions is referenced and it's a value to the union of the students from these three continents, with the Portuguese language as communication tool. The variety of the geological wealth and cultural of these regions, results in the common objective of their valuing like Geoparks. His creation on these three regions is a strategy with a great relevance to the socio-economic development. With the creation of this game, we promote the union of these 3 countries from these three continents, the universal values of the heritage richness that are offered by our planet.

  20. Supporting Dynamic Spectrum Access in Heterogeneous LTE+ Networks

    Energy Technology Data Exchange (ETDEWEB)

    Luiz A. DaSilva; Ryan E. Irwin; Mike Benonis

    2012-08-01

    As early as 2014, mobile network operators’ spectral capac- ity is expected to be overwhelmed by the demand brought on by new devices and applications. With Long Term Evo- lution Advanced (LTE+) networks likely as the future one world 4G standard, network operators may need to deploy a Dynamic Spectrum Access (DSA) overlay in Heterogeneous Networks (HetNets) to extend coverage, increase spectrum efficiency, and increase the capacity of these networks. In this paper, we propose three new management frameworks for DSA in an LTE+ HetNet: Spectrum Accountability Client, Cell Spectrum Management, and Domain Spectrum Man- agement. For these spectrum management frameworks, we define protocol interfaces and operational signaling scenar- ios to support cooperative sensing, spectrum lease manage- ment, and alarm scenarios for rule adjustment. We also quan- tify, through integer programs, the benefits of using DSA in an LTE+ HetNet, that can opportunistically reuse vacant TV and GSM spectrum. Using integer programs, we consider a topology using Geographic Information System data from the Blacksburg, VA metro area to assess the realistic benefits of DSA in an LTE+ HetNet.