WorldWideScience

Sample records for network measure defined

  1. Network Coded Software Defined Networking

    DEFF Research Database (Denmark)

    Krigslund, Jeppe; Hansen, Jonas; Roetter, Daniel Enrique Lucani

    2015-01-01

    Software Defined Networking (SDN) and Network Coding (NC) are two key concepts in networking that have garnered a large attention in recent years. On the one hand, SDN's potential to virtualize services in the Internet allows a large flexibility not only for routing data, but also to manage....... This paper advocates for the use of SDN to bring about future Internet and 5G network services by incorporating network coding (NC) functionalities. The inherent flexibility of both SDN and NC provides a fertile ground to envision more efficient, robust, and secure networking designs, that may also...

  2. Network Coded Software Defined Networking

    DEFF Research Database (Denmark)

    Hansen, Jonas; Roetter, Daniel Enrique Lucani; Krigslund, Jeppe

    2015-01-01

    Software defined networking has garnered large attention due to its potential to virtualize services in the Internet, introducing flexibility in the buffering, scheduling, processing, and routing of data in network routers. SDN breaks the deadlock that has kept Internet network protocols stagnant...... for decades, while applications and physical links have evolved. This article advocates for the use of SDN to bring about 5G network services by incorporating network coding (NC) functionalities. The latter constitutes a major leap forward compared to the state-of-the- art store and forward Internet paradigm...

  3. Software Defined Coded Networking

    DEFF Research Database (Denmark)

    Di Paola, Carla; Roetter, Daniel Enrique Lucani; Palazzo, Sergio

    2017-01-01

    the quality of each link and even across neighbouring links and using simulations to show that an additional reduction of packet transmission in the order of 40% is possible. Second, to advocate for the use of network coding (NC) jointly with software defined networking (SDN) providing an implementation...

  4. Software Defined Networking

    DEFF Research Database (Denmark)

    Caba, Cosmin Marius

    Network Service Providers (NSP) often choose to overprovision their networks instead of deploying proper Quality of Services (QoS) mechanisms that allow for traffic differentiation and predictable quality. This tendency of overprovisioning is not sustainable for the simple reason that network...... resources are limited. Hence, to counteract this trend, current QoS mechanisms must become simpler to deploy and operate, in order to motivate NSPs to employ QoS techniques instead of overprovisioning. Software Defined Networking (SDN) represents a paradigm shift in the way telecommunication and data...... generic perspective (e.g. service provisioning speed, resources availability). As a result, new mechanisms for providing QoS are proposed, solutions for SDN-specific QoS challenges are designed and tested, and new network management concepts are prototyped, all aiming to improve QoS for network services...

  5. So ware-Defined Network Solutions for Science Scenarios: Performance Testing Framework and Measurements

    Energy Technology Data Exchange (ETDEWEB)

    Settlemyer, Bradley [Los Alamos National Laboratory (LANL); Kettimuthu, R. [Argonne National Laboratory (ANL); Boley, Josh [Argonne National Laboratory (ANL); Katramatos, Dimitrios [Brookhaven National Laboratory (BNL); Rao, Nageswara S. [ORNL; Sen, Satyabrata [ORNL; Liu, Qiang [ORNL

    2018-01-01

    High-performance scientific work flows utilize supercomputers, scientific instruments, and large storage systems. Their executions require fast setup of a small number of dedicated network connections across the geographically distributed facility sites. We present Software-Defined Network (SDN) solutions consisting of site daemons that use dpctl, Floodlight, ONOS, or OpenDaylight controllers to set up these connections. The development of these SDN solutions could be quite disruptive to the infrastructure, while requiring a close coordination among multiple sites; in addition, the large number of possible controller and device combinations to investigate could make the infrastructure unavailable to regular users for extended periods of time. In response, we develop a Virtual Science Network Environment (VSNE) using virtual machines, Mininet, and custom scripts that support the development, testing, and evaluation of SDN solutions, without the constraints and expenses of multi-site physical infrastructures; furthermore, the chosen solutions can be directly transferred to production deployments. By complementing VSNE with a physical testbed, we conduct targeted performance tests of various SDN solutions to help choose the best candidates. In addition, we propose a switching response method to assess the setup times and throughput performances of different SDN solutions, and present experimental results that show their advantages and limitations.

  6. Software defined access networks

    OpenAIRE

    Maricato, José Miguel Duarte

    2016-01-01

    With the increase of internet usage and the exponential growth of bandwidth consumption due to the increasing number of users of new generation equipments and the creation of new services that consume increasingly higher bandwidths, it's necessary to nd solutions to meet these new requirements. Passive optical networks (PONs) promise to solve these problems by providing a better service to users and providers. PON networks are very attractive since they don't depend on a...

  7. Hardening Software Defined Networks

    Science.gov (United States)

    2014-07-01

    Zarifis,Peyman Kazemian:Leveraging SDN layering to systematically troubleshoot networks. HotSDN 2013: 37-42 21. Aurojit Panda ,Colin Scott,Ali Ghodsi...Unlimited. 21 ICN.SIGCOMM 2013: 147-158 23. Sangjin Han (U.C.Berkeley), Norbert Egi (Huawei Corp.), Aurojit Panda , Sylvia Ratnasamy (U.C.Berkeley...balancers, traffic-shapers, and so on. SDN brings software and processing power to bear on all this complexity. While a large Data Center may be

  8. Improving network management with Software Defined Networking

    International Nuclear Information System (INIS)

    Dzhunev, Pavel

    2013-01-01

    Software-defined networking (SDN) is developed as an alternative to closed networks in centers for data processing by providing a means to separate the control layer data layer switches, and routers. SDN introduces new possibilities for network management and configuration methods. In this article, we identify problems with the current state-of-the-art network configuration and management mechanisms and introduce mechanisms to improve various aspects of network management

  9. Defining nodes in complex brain networks

    Directory of Open Access Journals (Sweden)

    Matthew Lawrence Stanley

    2013-11-01

    Full Text Available Network science holds great promise for expanding our understanding of the human brain in health, disease, development, and aging. Network analyses are quickly becoming the method of choice for analyzing functional MRI data. However, many technical issues have yet to be confronted in order to optimize results. One particular issue that remains controversial in functional brain network analyses is the definition of a network node. In functional brain networks a node represents some predefined collection of brain tissue, and an edge measures the functional connectivity between pairs of nodes. The characteristics of a node, chosen by the researcher, vary considerably in the literature. This manuscript reviews the current state of the art based on published manuscripts and highlights the strengths and weaknesses of three main methods for defining nodes. Voxel-wise networks are constructed by assigning a node to each, equally sized brain area (voxel. The fMRI time-series recorded from each voxel is then used to create the functional network. Anatomical methods utilize atlases to define the nodes based on brain structure. The fMRI time-series from all voxels within the anatomical area are averaged and subsequently used to generate the network. Functional activation methods rely on data from traditional fMRI activation studies, often from databases, to identify network nodes. Such methods identify the peaks or centers of mass from activation maps to determine the location of the nodes. Small (~10-20 millimeter diameter spheres located at the coordinates of the activation foci are then applied to the data being used in the network analysis. The fMRI time-series from all voxels in the sphere are then averaged, and the resultant time series is used to generate the network. We attempt to clarify the discussion and move the study of complex brain networks forward. While the correct method to be used remains an open, possibly unsolvable question that

  10. Languages for Software-Defined Networks

    Science.gov (United States)

    2013-02-01

    switches, firewalls, and middleboxes) with closed and proprietary configuration inter- faces. Software - Defined Networks ( SDN ) are poised to change...how- ever, have seen growing interest in software - defined networks ( SDNs ), in which a logically-centralized controller manages the packet-processing...switches, firewalls, and middleboxes) with closed and proprietary configuration interfaces. Software - Defined Networks ( SDN ) are poised to change this

  11. Troubleshooting of Software Defined Networks

    OpenAIRE

    Sistek, Haris

    2015-01-01

    Network troubleshooting is a field where automation is sorely needed. While the network has grown in many other ways since 1960s, the tools we use to troubleshoot and manage it have stayed very much the same. Could we use the programmability of SDN to automate this problem? In this thesis work, we developed a prototype that would systematically troubleshoot the network with automation. The prototype automatically captures network behaviour, matches it against a network policy and creates its ...

  12. Software defined network inference with evolutionary optimal observation matrices

    OpenAIRE

    Malboubi, M; Gong, Y; Yang, Z; Wang, X; Chuah, CN; Sharma, P

    2017-01-01

    © 2017 Elsevier B.V. A key requirement for network management is the accurate and reliable monitoring of relevant network characteristics. In today's large-scale networks, this is a challenging task due to the scarcity of network measurement resources and the hard constraints that this imposes. This paper proposes a new framework, called SNIPER, which leverages the flexibility provided by Software-Defined Networking (SDN) to design the optimal observation or measurement matrix that can lead t...

  13. Software Defined Networking Demands on Software Technologies

    DEFF Research Database (Denmark)

    Galinac Grbac, T.; Caba, Cosmin Marius; Soler, José

    2015-01-01

    Software Defined Networking (SDN) is a networking approach based on a centralized control plane architecture with standardised interfaces between control and data planes. SDN enables fast configuration and reconfiguration of the network to enhance resource utilization and service performances....... This new approach enables a more dynamic and flexible network, which may adapt to user needs and application requirements. To this end, systemized solutions must be implemented in network software, aiming to provide secure network services that meet the required service performance levels. In this paper......, we review this new approach to networking from an architectural point of view, and identify and discuss some critical quality issues that require new developments in software technologies. These issues we discuss along with use case scenarios. Here in this paper we aim to identify challenges...

  14. Software defined networks a comprehensive approach

    CERN Document Server

    Goransson, Paul

    2014-01-01

    Software Defined Networks discusses the historical networking environment that gave rise to SDN, as well as the latest advances in SDN technology. The book gives you the state of the art knowledge needed for successful deployment of an SDN, including: How to explain to the non-technical business decision makers in your organization the potential benefits, as well as the risks, in shifting parts of a network to the SDN modelHow to make intelligent decisions about when to integrate SDN technologies in a networkHow to decide if your organization should be developing its own SDN applications or

  15. Reconfigurable network systems and software-defined networking

    OpenAIRE

    Zilberman, N.; Watts, P. M.; Rotsos, C.; Moore, A. W.

    2015-01-01

    Modern high-speed networks have evolved from relatively static networks to highly adaptive networks facilitating dynamic reconfiguration. This evolution has influenced all levels of network design and management, introducing increased programmability and configuration flexibility. This influence has extended from the lowest level of physical hardware interfaces to the highest level of network management by software. A key representative of this evolution is the emergence of software-defined n...

  16. Distributed controller clustering in software defined networks.

    Directory of Open Access Journals (Sweden)

    Ahmed Abdelaziz

    Full Text Available Software Defined Networking (SDN is an emerging promising paradigm for network management because of its centralized network intelligence. However, the centralized control architecture of the software-defined networks (SDNs brings novel challenges of reliability, scalability, fault tolerance and interoperability. In this paper, we proposed a novel clustered distributed controller architecture in the real setting of SDNs. The distributed cluster implementation comprises of multiple popular SDN controllers. The proposed mechanism is evaluated using a real world network topology running on top of an emulated SDN environment. The result shows that the proposed distributed controller clustering mechanism is able to significantly reduce the average latency from 8.1% to 1.6%, the packet loss from 5.22% to 4.15%, compared to distributed controller without clustering running on HP Virtual Application Network (VAN SDN and Open Network Operating System (ONOS controllers respectively. Moreover, proposed method also shows reasonable CPU utilization results. Furthermore, the proposed mechanism makes possible to handle unexpected load fluctuations while maintaining a continuous network operation, even when there is a controller failure. The paper is a potential contribution stepping towards addressing the issues of reliability, scalability, fault tolerance, and inter-operability.

  17. Distributed controller clustering in software defined networks.

    Science.gov (United States)

    Abdelaziz, Ahmed; Fong, Ang Tan; Gani, Abdullah; Garba, Usman; Khan, Suleman; Akhunzada, Adnan; Talebian, Hamid; Choo, Kim-Kwang Raymond

    2017-01-01

    Software Defined Networking (SDN) is an emerging promising paradigm for network management because of its centralized network intelligence. However, the centralized control architecture of the software-defined networks (SDNs) brings novel challenges of reliability, scalability, fault tolerance and interoperability. In this paper, we proposed a novel clustered distributed controller architecture in the real setting of SDNs. The distributed cluster implementation comprises of multiple popular SDN controllers. The proposed mechanism is evaluated using a real world network topology running on top of an emulated SDN environment. The result shows that the proposed distributed controller clustering mechanism is able to significantly reduce the average latency from 8.1% to 1.6%, the packet loss from 5.22% to 4.15%, compared to distributed controller without clustering running on HP Virtual Application Network (VAN) SDN and Open Network Operating System (ONOS) controllers respectively. Moreover, proposed method also shows reasonable CPU utilization results. Furthermore, the proposed mechanism makes possible to handle unexpected load fluctuations while maintaining a continuous network operation, even when there is a controller failure. The paper is a potential contribution stepping towards addressing the issues of reliability, scalability, fault tolerance, and inter-operability.

  18. Stateless multicast switching in software defined networks

    OpenAIRE

    Reed, Martin J.; Al-Naday, Mays; Thomos, Nikolaos; Trossen, Dirk; Petropoulos, George; Spirou, Spiros

    2016-01-01

    Multicast data delivery can significantly reduce traffic in operators' networks, but has been limited in deployment due to concerns such as the scalability of state management. This paper shows how multicast can be implemented in contemporary software defined networking (SDN) switches, with less state than existing unicast switching strategies, by utilising a Bloom Filter (BF) based switching technique. Furthermore, the proposed mechanism uses only proactive rule insertion, and thus, is not l...

  19. Software Defined Networks in Wireless Sensor Architectures

    Directory of Open Access Journals (Sweden)

    Jesús Antonio Puente Fernández

    2018-03-01

    Full Text Available Nowadays, different protocols coexist in Internet that provides services to users. Unfortunately, control decisions and distributed management make it hard to control networks. These problems result in an inefficient and unpredictable network behaviour. Software Defined Networks (SDN is a new concept of network architecture. It intends to be more flexible and to simplify the management in networks with respect to traditional architectures. Each of these aspects are possible because of the separation of control plane (controller and data plane (switches in network devices. OpenFlow is the most common protocol for SDN networks that provides the communication between control and data planes. Moreover, the advantage of decoupling control and data planes enables a quick evolution of protocols and also its deployment without replacing data plane switches. In this survey, we review the SDN technology and the OpenFlow protocol and their related works. Specifically, we describe some technologies as Wireless Sensor Networks and Wireless Cellular Networks and how SDN can be included within them in order to solve their challenges. We classify different solutions for each technology attending to the problem that is being fixed.

  20. Big data and software defined networks

    CERN Document Server

    Taheri, Javid

    2018-01-01

    Big Data Analytics and Software Defined Networking (SDN) are helping to drive the management of data usage of the extraordinary increase of computer processing power provided by Cloud Data Centres (CDCs). This new book investigates areas where Big-Data and SDN can help each other in delivering more efficient services.

  1. Software defined networking applications in distributed datacenters

    CERN Document Server

    Qi, Heng

    2016-01-01

    This SpringerBrief provides essential insights on the SDN application designing and deployment in distributed datacenters. In this book, three key problems are discussed: SDN application designing, SDN deployment and SDN management. This book demonstrates how to design the SDN-based request allocation application in distributed datacenters. It also presents solutions for SDN controller placement to deploy SDN in distributed datacenters. Finally, an SDN management system is proposed to guarantee the performance of datacenter networks which are covered and controlled by many heterogeneous controllers. Researchers and practitioners alike will find this book a valuable resource for further study on Software Defined Networking. .

  2. Traffic Policing in Dynamic Military Networks Using Software Defined Networking

    OpenAIRE

    Skappel, Hans Fredrik

    2016-01-01

    This thesis looks at how Software Defined Networking (SDN) can be used to provide traffic engineering and to police traffic in an Operational Military Network (OMN). SDN is a concept where the control plane is separated from the forwarding plane, and the control plane is capable of controlling forwarding plane elements located on multiple network nodes using the OpenFlow protocol. Specifically, we have discussed the problems in OMNs, and possible SDN approaches to mitigate the challenges. Bas...

  3. Defining and Measuring Safeguards Culture

    International Nuclear Information System (INIS)

    Frazar, Sarah L.; Mladineo, Stephen V.

    2010-01-01

    In light of the shift toward State Level Evaluations and information driven safeguards, this paper offers a refined definition of safeguards culture and a set of metrics for measuring the extent to which a safeguards culture exists in a state. Where the IAEA is able to use the definition and metrics to come to a positive conclusion about the country, it may help reduce the burden on the Agency and the state.

  4. Utilising artificial intelligence in software defined wireless sensor network

    CSIR Research Space (South Africa)

    Matlou, OG

    2017-10-01

    Full Text Available Software Defined Wireless Sensor Network (SDWSN) is realised by infusing Software Defined Network (SDN) model in Wireless Sensor Network (WSN), Reason for that is to overcome the challenges of WSN. Artificial Intelligence (AI) and machine learning...

  5. Software-defined Quantum Networking Ecosystem

    Energy Technology Data Exchange (ETDEWEB)

    2017-01-01

    The software enables a user to perform modeling and simulation of software-defined quantum networks. The software addresses the problem of how to synchronize transmission of quantum and classical signals through multi-node networks and to demonstrate quantum information protocols such as quantum teleportation. The software approaches this problem by generating a graphical model of the underlying network and attributing properties to each node and link in the graph. The graphical model is then simulated using a combination of discrete-event simulators to calculate the expected state of each node and link in the graph at a future time. A user interacts with the software by providing an initial network model and instantiating methods for the nodes to transmit information with each other. This includes writing application scripts in python that make use of the software library interfaces. A user then initiates the application scripts, which invokes the software simulation. The user then uses the built-in diagnostic tools to query the state of the simulation and to collect statistics on synchronization.

  6. Fingerprinting Software Defined Networks and Controllers

    Science.gov (United States)

    2015-03-01

    rps requests per second RTT Round-Trip Time SDN Software Defined Networking SOM Self-Organizing Map STP Spanning Tree Protocol TRW-CB Threshold Random...Protocol ( STP ) updates), in which case the frame will be “punted” from the forwarding lookup process and processed by the route processor [9]. The act of...environment 20 to accomplish the needs of B4. In addition to Google, the SDN market is expected to grow beyond $35 billion by April 2018 [31]. The rate

  7. Employing Deceptive Dynamic Network Topology Through Software-Defined Networking

    Science.gov (United States)

    2014-03-01

    actions. From [64] . . . . . 37 xi THIS PAGE INTENTIONALLY LEFT BLANK xii List of Acronyms and Abbreviations ACL Access Control List API Application...can be extremely useful in topology mapping through various latency-based geolocation methods [35], [36], [37]. PING 1 7 2 . 2 0 . 5 . 2 ( 1 7 2 . 2 0...defined northbound Applica- tion Programming Interfaces ( APIs ). Figure 3.1: Software-Defined Network Architecture. From [8] 29 3.3 SDN OpenFlow

  8. Enabling software defined networking experiments in networked critical infrastructures

    Directory of Open Access Journals (Sweden)

    Béla Genge

    2014-05-01

    Full Text Available Nowadays, the fact that Networked Critical Infrastructures (NCI, e.g., power plants, water plants, oil and gas distribution infrastructures, and electricity grids, are targeted by significant cyber threats is well known. Nevertheless, recent research has shown that specific characteristics of NCI can be exploited in the enabling of more efficient mitigation techniques, while novel techniques from the field of IP networks can bring significant advantages. In this paper we explore the interconnection of NCI communication infrastructures with Software Defined Networking (SDN-enabled network topologies. SDN provides the means to create virtual networking services and to implement global networking decisions. It relies on OpenFlow to enable communication with remote devices and has been recently categorized as the “Next Big Technology”, which will revolutionize the way decisions are implemented in switches and routers. Therefore, the paper documents the first steps towards enabling an SDN-NCI and presents the impact of a Denial of Service experiment over traffic resulting from an XBee sensor network which is routed across an emulated SDN network.

  9. Clustering and Flow Conservation Monitoring Tool for Software Defined Networks

    Directory of Open Access Journals (Sweden)

    Jesús Antonio Puente Fernández

    2018-04-01

    Full Text Available Prediction systems present some challenges on two fronts: the relation between video quality and observed session features and on the other hand, dynamics changes on the video quality. Software Defined Networks (SDN is a new concept of network architecture that provides the separation of control plane (controller and data plane (switches in network devices. Due to the existence of the southbound interface, it is possible to deploy monitoring tools to obtain the network status and retrieve a statistics collection. Therefore, achieving the most accurate statistics depends on a strategy of monitoring and information requests of network devices. In this paper, we propose an enhanced algorithm for requesting statistics to measure the traffic flow in SDN networks. Such an algorithm is based on grouping network switches in clusters focusing on their number of ports to apply different monitoring techniques. Such grouping occurs by avoiding monitoring queries in network switches with common characteristics and then, by omitting redundant information. In this way, the present proposal decreases the number of monitoring queries to switches, improving the network traffic and preventing the switching overload. We have tested our optimization in a video streaming simulation using different types of videos. The experiments and comparison with traditional monitoring techniques demonstrate the feasibility of our proposal maintaining similar values decreasing the number of queries to the switches.

  10. Clustering and Flow Conservation Monitoring Tool for Software Defined Networks.

    Science.gov (United States)

    Puente Fernández, Jesús Antonio; García Villalba, Luis Javier; Kim, Tai-Hoon

    2018-04-03

    Prediction systems present some challenges on two fronts: the relation between video quality and observed session features and on the other hand, dynamics changes on the video quality. Software Defined Networks (SDN) is a new concept of network architecture that provides the separation of control plane (controller) and data plane (switches) in network devices. Due to the existence of the southbound interface, it is possible to deploy monitoring tools to obtain the network status and retrieve a statistics collection. Therefore, achieving the most accurate statistics depends on a strategy of monitoring and information requests of network devices. In this paper, we propose an enhanced algorithm for requesting statistics to measure the traffic flow in SDN networks. Such an algorithm is based on grouping network switches in clusters focusing on their number of ports to apply different monitoring techniques. Such grouping occurs by avoiding monitoring queries in network switches with common characteristics and then, by omitting redundant information. In this way, the present proposal decreases the number of monitoring queries to switches, improving the network traffic and preventing the switching overload. We have tested our optimization in a video streaming simulation using different types of videos. The experiments and comparison with traditional monitoring techniques demonstrate the feasibility of our proposal maintaining similar values decreasing the number of queries to the switches.

  11. Poster: A Software-Defined Multi-Camera Network

    OpenAIRE

    Chen, Po-Yen; Chen, Chien; Selvaraj, Parthiban; Claesen, Luc

    2016-01-01

    The widespread popularity of OpenFlow leads to a significant increase in the number of applications developed in SoftwareDefined Networking (SDN). In this work, we propose the architecture of a Software-Defined Multi-Camera Network consisting of small, flexible, economic, and programmable cameras which combine the functions of the processor, switch, and camera. A Software-Defined Multi-Camera Network can effectively reduce the overall network bandwidth and reduce a large amount of the Capex a...

  12. Software defined networking with OpenFlow

    CERN Document Server

    Azodolmolky, Siamak

    2013-01-01

    A step-by-step, example-based guide which will help you gain hands-on experience with the platforms and debugging tools on OpenFlow.If you are a network engineer, architect, junior researcher or an application developer, this book is ideal for you. You will need to have some level of network experience, knowledge of broad networking concepts, and some familiarity with day- to- day operation of computer networks. Ideally, you should also be familiar with programing scripting/languages (especially Python and Java), and system virtualization.

  13. Implicitly Defined Neural Networks for Sequence Labeling

    Science.gov (United States)

    2017-07-31

    ularity has soared for the Long Short - Term Memory (LSTM) (Hochreiter and Schmidhuber, 1997) and vari- ants such as Gated Recurrent Unit (GRU) (Cho et...610. Sepp Hochreiter and Jürgen Schmidhuber. 1997. Long short - term memory . Neural computation 9(8):1735– 1780. Zhiheng Huang, Wei Xu, and Kai Yu. 2015...network are coupled together, in order to improve perfor- mance on complex, long -range dependencies in either direction of a sequence. We contrast our

  14. Software defined wireless sensor networks security challenges

    CSIR Research Space (South Africa)

    Kgogo, T

    2017-09-01

    Full Text Available party development [28]. Moreover, there is a new attack that fingerprints SDN network and launches more efficient resource consumption attacks like DDoS. In general, SDN security vulnerabilities comes from the absence of integration with existing... resilience in NOX that uses its component organization. Moreover, a Primary-Backup method was introduced to enhanve the resilience of the SDN. “SDN-based DDoS blocking scheme” [38] DoS/DDoS attack specifically on the controller DDoS Blocking...

  15. Defining Multiple Chronic Conditions for Quality Measurement.

    Science.gov (United States)

    Drye, Elizabeth E; Altaf, Faseeha K; Lipska, Kasia J; Spatz, Erica S; Montague, Julia A; Bao, Haikun; Parzynski, Craig S; Ross, Joseph S; Bernheim, Susannah M; Krumholz, Harlan M; Lin, Zhenqiu

    2018-02-01

    Patients with multiple chronic conditions (MCCs) are a critical but undefined group for quality measurement. We present a generally applicable systematic approach to defining an MCC cohort of Medicare fee-for-service beneficiaries that we developed for a national quality measure, risk-standardized rates of unplanned admissions for Accountable Care Organizations. To define the MCC cohort we: (1) identified potential chronic conditions; (2) set criteria for cohort conditions based on MCC framework and measure concept; (3) applied the criteria informed by empirical analysis, experts, and the public; (4) described "broader" and "narrower" cohorts; and (5) selected final cohort with stakeholder input. Subjects were patients with chronic conditions. Participants included 21.8 million Medicare fee-for-service beneficiaries in 2012 aged 65 years and above with ≥1 of 27 Medicare Chronic Condition Warehouse condition(s). In total, 10 chronic conditions were identified based on our criteria; 8 of these 10 were associated with notably increased admission risk when co-occurring. A broader cohort (2+ of the 8 conditions) included 4.9 million beneficiaries (23% of total cohort) with an admission rate of 70 per 100 person-years. It captured 53% of total admissions. The narrower cohort (3+ conditions) had 2.2 million beneficiaries (10%) with 100 admissions per 100 person-years and captured 32% of admissions. Most stakeholders viewed the broader cohort as best aligned with the measure concept. By systematically narrowing chronic conditions to those most relevant to the outcome and incorporating stakeholder input, we defined an MCC admission measure cohort supported by stakeholders. This approach can be used as a model for other MCC outcome measures.

  16. Graphs for information security control in software defined networks

    Science.gov (United States)

    Grusho, Alexander A.; Abaev, Pavel O.; Shorgin, Sergey Ya.; Timonina, Elena E.

    2017-07-01

    Information security control in software defined networks (SDN) is connected with execution of the security policy rules regulating information accesses and protection against distribution of the malicious code and harmful influences. The paper offers a representation of a security policy in the form of hierarchical structure which in case of distribution of resources for the solution of tasks defines graphs of admissible interactions in a networks. These graphs define commutation tables of switches via the SDN controller.

  17. Software defined networks reactive flow programming and load balance switching

    OpenAIRE

    Καλλιανιώτης, Νικόλαος; Kallianiotis, Nikolaos

    2017-01-01

    This project serves as a Master Thesis as the requirements of the master’s programme Master of Digital Communications and Networks. It proposes load balancing algorithms applied to Software-Defined Networks to achieve the best possible resource utilisation of each of the links present in a network. The open-sources Opendaylight project and Floodlight project are used as SDN controllers, and the network is emulated using Mininet software

  18. Detecting P2P Botnet in Software Defined Networks

    Directory of Open Access Journals (Sweden)

    Shang-Chiuan Su

    2018-01-01

    Full Text Available Software Defined Network separates the control plane from network equipment and has great advantage in network management as compared with traditional approaches. With this paradigm, the security issues persist to exist and could become even worse because of the flexibility on handling the packets. In this paper we propose an effective framework by integrating SDN and machine learning to detect and categorize P2P network traffics. This work provides experimental evidence showing that our approach can automatically analyze network traffic and flexibly change flow entries in OpenFlow switches through the SDN controller. This can effectively help the network administrators manage related security problems.

  19. Service-oriented Software Defined Optical Networks for Cloud Computing

    Science.gov (United States)

    Liu, Yuze; Li, Hui; Ji, Yuefeng

    2017-10-01

    With the development of big data and cloud computing technology, the traditional software-defined network is facing new challenges (e.g., ubiquitous accessibility, higher bandwidth, more flexible management and greater security). This paper proposes a new service-oriented software defined optical network architecture, including a resource layer, a service abstract layer, a control layer and an application layer. We then dwell on the corresponding service providing method. Different service ID is used to identify the service a device can offer. Finally, we experimentally evaluate that proposed service providing method can be applied to transmit different services based on the service ID in the service-oriented software defined optical network.

  20. A research on the application of software defined networking in satellite network architecture

    Science.gov (United States)

    Song, Huan; Chen, Jinqiang; Cao, Suzhi; Cui, Dandan; Li, Tong; Su, Yuxing

    2017-10-01

    Software defined network is a new type of network architecture, which decouples control plane and data plane of traditional network, has the feature of flexible configurations and is a direction of the next generation terrestrial Internet development. Satellite network is an important part of the space-ground integrated information network, while the traditional satellite network has the disadvantages of difficult network topology maintenance and slow configuration. The application of SDN technology in satellite network can solve these problems that traditional satellite network faces. At present, the research on the application of SDN technology in satellite network is still in the stage of preliminary study. In this paper, we start with introducing the SDN technology and satellite network architecture. Then we mainly introduce software defined satellite network architecture, as well as the comparison of different software defined satellite network architecture and satellite network virtualization. Finally, the present research status and development trend of SDN technology in satellite network are analyzed.

  1. A Quantum Cryptography Communication Network Based on Software Defined Network

    Directory of Open Access Journals (Sweden)

    Zhang Hongliang

    2018-01-01

    Full Text Available With the development of the Internet, information security has attracted great attention in today’s society, and quantum cryptography communication network based on quantum key distribution (QKD is a very important part of this field, since the quantum key distribution combined with one-time-pad encryption scheme can guarantee the unconditional security of the information. The secret key generated by quantum key distribution protocols is a very valuable resource, so making full use of key resources is particularly important. Software definition network (SDN is a new type of network architecture, and it separates the control plane and the data plane of network devices through OpenFlow technology, thus it realizes the flexible control of the network resources. In this paper, a quantum cryptography communication network model based on SDN is proposed to realize the flexible control of quantum key resources in the whole cryptography communication network. Moreover, we propose a routing algorithm which takes into account both the hops and the end-to-end availible keys, so that the secret key generated by QKD can be used effectively. We also simulate this quantum cryptography communication network, and the result shows that based on SDN and the proposed routing algorithm the performance of this network is improved since the effective use of the quantum key resources.

  2. Future Scenarios for Software-Defined Metro and Access Networks and Software-Defined Photonics

    Directory of Open Access Journals (Sweden)

    Tommaso Muciaccia

    2017-01-01

    Full Text Available In recent years, architectures, devices, and components in telecommunication networks have been challenged by evolutionary and revolutionary factors which are drastically changing the traffic features. Most of these changes imply the need for major re-configurability and programmability not only in data-centers and core networks, but also in the metro-access segment. In a wide variety of contexts, this necessity has been addressed by the proposed introduction of the innovative paradigm of software-defined networks (SDNs. Several solutions inspired by the SDN model have been recently proposed also for metro and access networks, where the adoption of a new generation of software-defined reconfigurable integrated photonic devices is highly desirable. In this paper, we review the possible future application scenarios for software-defined metro and access networks and software-defined photonics (SDP, on the base of analytics, statistics, and surveys. This work describes the reasons underpinning the presented radical change of paradigm and summarizes the most significant solutions proposed in literature, with a specific emphasis to physical-layer reconfigurable networks and a focus on both architectures and devices.

  3. Mitigating the controller performance bottlenecks in Software Defined Networks

    DEFF Research Database (Denmark)

    Caba, Cosmin Marius; Soler, José

    2016-01-01

    The centralization of the control plane decision logic in Software Defined Networking (SDN) has raised concerns regarding the performance of the SDN Controller (SDNC) when the network scales up. A number of solutions have been proposed in the literature to address these concerns. This paper...

  4. SONEP: A Software-Defined Optical Network Emulation Platform

    DEFF Research Database (Denmark)

    Azodolmolky, Siamak; Petersen, Martin Nordal; Fagertun, Anna Manolova

    2014-01-01

    Network emulation has been one of the tools of choice for conducting experiments on commodity hardware. In the absence of an easy to use optical network test-bed, researchers can significantly benefit from the availability of a flexible/programmable optical network emulation platform. Exploiting...... the lightweight system virtualization, which is recently supported in modern operating systems, in this work we present the architecture of a Software-Defined Network (SDN) emulation platform for transport optical networks and investigate its usage in a use-case scenario. To the best of our knowledge......, this is for the first time that an SDN-based emulation platform is proposed for modeling and performance evaluation of optical networks. Coupled with recent trend of extension of SDN towards transport (optical) networks, the presented tool can facilitate the evaluation of innovative idea before actual implementations...

  5. Urban Green Network Design: Defining green network from an urban planning perspective

    Directory of Open Access Journals (Sweden)

    Andrea Tulisi

    2017-08-01

    Full Text Available From the theoretical context of Smart City various studies have emerged that adopt an analytical approach and description of urban phenomena based on the principles of “network design”; this line of research uses the network systems theory to define the principles that regulate the relationships among the various elements of urban sub-systems in order to optimize their functionality. From the same theoretical basis, urban greenspaces have also been studied as networks, by means of the creation of models capable of measuring the performance of the system in its entirety, posing the basis of a new multy-disciplinary research field called green network. This paper presents the results of research aimed at clarifying the meaning of green network from an urban planning perspective through a lexical analysis applied to a textual corpus of more than 300 abstracts of research papers that have dealt with this topic over the last twenty years. The results show that the concept of green network appears still fuzzy and unclear, due to the different meaning given to the term “green” and to an incorrect use of the term “network”, often referred to as a generic set of natural areas present in a city, without any reference to the network system theory or to the basic rules linking these elements together. For this reason, the paper proposes a unique definition of green network from an urban planning perspective that takes into account the contribution of other research areas to effective green infrastructure planning. This is the concept of “urban green network design” defined as “an urban planning practice, supported by decision support tools able to model green infrastructure as network, composed by natural and semi-natural areas, whose connections are modelled according to specific variables, in order to deliver an equal distribution of public services for enhancing the quality of life as well as a wide range of ecosystem services”.

  6. Protocol independent transmission method in software defined optical network

    Science.gov (United States)

    Liu, Yuze; Li, Hui; Hou, Yanfang; Qiu, Yajun; Ji, Yuefeng

    2016-10-01

    With the development of big data and cloud computing technology, the traditional software-defined network is facing new challenges (e.i., ubiquitous accessibility, higher bandwidth, more flexible management and greater security). Using a proprietary protocol or encoding format is a way to improve information security. However, the flow, which carried by proprietary protocol or code, cannot go through the traditional IP network. In addition, ultra- high-definition video transmission service once again become a hot spot. Traditionally, in the IP network, the Serial Digital Interface (SDI) signal must be compressed. This approach offers additional advantages but also bring some disadvantages such as signal degradation and high latency. To some extent, HD-SDI can also be regard as a proprietary protocol, which need transparent transmission such as optical channel. However, traditional optical networks cannot support flexible traffics . In response to aforementioned challenges for future network, one immediate solution would be to use NFV technology to abstract the network infrastructure and provide an all-optical switching topology graph for the SDN control plane. This paper proposes a new service-based software defined optical network architecture, including an infrastructure layer, a virtualization layer, a service abstract layer and an application layer. We then dwell on the corresponding service providing method in order to implement the protocol-independent transport. Finally, we experimentally evaluate that proposed service providing method can be applied to transmit the HD-SDI signal in the software-defined optical network.

  7. 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.

  8. Minimizing communication cost among distributed controllers in software defined networks

    Science.gov (United States)

    Arlimatti, Shivaleela; Elbreiki, Walid; Hassan, Suhaidi; Habbal, Adib; Elshaikh, Mohamed

    2016-08-01

    Software Defined Networking (SDN) is a new paradigm to increase the flexibility of today's network by promising for a programmable network. The fundamental idea behind this new architecture is to simplify network complexity by decoupling control plane and data plane of the network devices, and by making the control plane centralized. Recently controllers have distributed to solve the problem of single point of failure, and to increase scalability and flexibility during workload distribution. Even though, controllers are flexible and scalable to accommodate more number of network switches, yet the problem of intercommunication cost between distributed controllers is still challenging issue in the Software Defined Network environment. This paper, aims to fill the gap by proposing a new mechanism, which minimizes intercommunication cost with graph partitioning algorithm, an NP hard problem. The methodology proposed in this paper is, swapping of network elements between controller domains to minimize communication cost by calculating communication gain. The swapping of elements minimizes inter and intra communication cost among network domains. We validate our work with the OMNeT++ simulation environment tool. Simulation results show that the proposed mechanism minimizes the inter domain communication cost among controllers compared to traditional distributed controllers.

  9. Measuring distances between complex networks

    International Nuclear Information System (INIS)

    Andrade, Roberto F.S.; Miranda, Jose G.V.; Pinho, Suani T.R.; Lobao, Thierry Petit

    2008-01-01

    A previously introduced concept of higher order neighborhoods in complex networks, [R.F.S. Andrade, J.G.V. Miranda, T.P. Lobao, Phys. Rev. E 73 (2006) 046101] is used to define a distance between networks with the same number of nodes. With such measure, expressed in terms of the matrix elements of the neighborhood matrices of each network, it is possible to compare, in a quantitative way, how far apart in the space of neighborhood matrices two networks are. The distance between these matrices depends on both the network topologies and the adopted node numberings. While the numbering of one network is fixed, a Monte Carlo algorithm is used to find the best numbering of the other network, in the sense that it minimizes the distance between the matrices. The minimal value found for the distance reflects differences in the neighborhood structures of the two networks that arise only from distinct topologies. This procedure ends up by providing a projection of the first network on the pattern of the second one. Examples are worked out allowing for a quantitative comparison for distances among distinct networks, as well as among distinct realizations of random networks

  10. Spectrum and network measurements

    CERN Document Server

    Witte, Robert A

    2014-01-01

    This new edition of Spectrum and Network Measurements enables readers to understand the basic theory, relate it to measured results, and apply it when creating new designs. This comprehensive treatment of frequency domain measurements successfully consolidates all the pertinent theory into one text. It covers the theory and practice of spectrum and network measurements in electronic systems. It also provides thorough coverage of Fourier analysis, transmission lines, intermodulation distortion, signal-to-noise ratio and S-parameters.

  11. Software-Defined Congestion Control Algorithm for IP Networks

    Directory of Open Access Journals (Sweden)

    Yao Hu

    2017-01-01

    Full Text Available The rapid evolution of computer networks, increase in the number of Internet users, and popularity of multimedia applications have exacerbated the congestion control problem. Congestion control is a key factor in ensuring network stability and robustness. When the underlying network and flow information are unknown, the transmission control protocol (TCP must increase or reduce the size of the congestion window to adjust to the changes of traffic in the Internet Protocol (IP network. However, it is possible that a software-defined approach can relieve the network congestion problem more efficiently. This approach has the characteristic of centralized control and can obtain a global topology for unified network management. In this paper, we propose a software-defined congestion control (SDCC algorithm for an IP network. We consider the difference between TCP and the user datagram protocol (UDP and propose a new method to judge node congestion. We initially apply the congestion control mechanism in the congested nodes and then optimize the link utilization to control network congestion.

  12. A Formal Model and Verification Problems for Software Defined Networks

    Directory of Open Access Journals (Sweden)

    V. A. Zakharov

    2013-01-01

    Full Text Available Software-defined networking (SDN is an approach to building computer networks that separate and abstract data planes and control planes of these systems. In a SDN a centralized controller manages a distributed set of switches. A set of open commands for packet forwarding and flow-table updating was defined in the form of a protocol known as OpenFlow. In this paper we describe an abstract formal model of SDN, introduce a tentative language for specification of SDN forwarding policies, and set up formally model-checking problems for SDN.

  13. Dynamic Network Security Control Using Software Defined Networking

    Science.gov (United States)

    2016-03-24

    technologies such as Open vSwitch (OVS) [26], OpenFlow [22], Cisco Nexus 5000V [27], and IBM 5000V [28]. 2.2.4 OpenFlow. The Open Networking Foundation...companies with more than 64 OpenFlow products on the market . Since 2009, ONF released four major revisions to OpenFlow and the latest proposed...2015 from http://www.openvswitch.org, 2014. 27. Cisco Systems. Cisco Nexus 5000 Series Architecture. Retrieved 9 Oc- tober, 2015 from http

  14. Coexistence of Named Data Networking (NDN) and Software-Defined Networking (SDN)

    Science.gov (United States)

    2017-09-01

    COD) for deploying the data found by CL at optimal node, and c) Path Optimizer (PO) for balancing network traffic in both spatial and temporal...and software- defined networking with big data . Ithaca (NY): Cornell University Library; 2016 Nov 19. arXiv: 1611.06299v1 [cs.NI]. Approved for...ARL-TN-0845 ● SEP 2017 US Army Research Laboratory Coexistence of Named Data Networking (NDN) and Software-Defined Networking

  15. Software defined network architecture based research on load balancing strategy

    Science.gov (United States)

    You, Xiaoqian; Wu, Yang

    2018-05-01

    As a new type network architecture, software defined network has the key idea of separating the control place of the network from the transmission plane, to manage and control the network in a concentrated way; in addition, the network interface is opened on the control layer and the data layer, so as to achieve programmable control of the network. Considering that only the single shortest route is taken into the calculation of traditional network data flow transmission, and congestion and resource consumption caused by excessive load of link circuits are ignored, a link circuit load based flow media business QoS gurantee system is proposed in this article to divide the flow in the network into ordinary data flow and QoS flow. In this way, it supervises the link circuit load with the controller so as to calculate reasonable route rapidly and issue the flow table to the exchanger, to finish rapid data transmission. In addition, it establishes a simulation platform to acquire optimized result through simulation experiment.

  16. Validating User Flows to Protect Software Defined Network Environments

    Directory of Open Access Journals (Sweden)

    Ihsan H. Abdulqadder

    2018-01-01

    Full Text Available Software Defined Network is a promising network paradigm which has led to several security threats in SDN applications that involve user flows, switches, and controllers in the network. Threats as spoofing, tampering, information disclosure, Denial of Service, flow table overloading, and so on have been addressed by many researchers. In this paper, we present novel SDN design to solve three security threats: flow table overloading is solved by constructing a star topology-based architecture, unsupervised hashing method mitigates link spoofing attack, and fuzzy classifier combined with L1-ELM running on a neural network for isolating anomaly packets from normal packets. For effective flow migration Discrete-Time Finite-State Markov Chain model is applied. Extensive simulations using OMNeT++ demonstrate the performance of our proposed approach, which is better at preserving holding time than are other state-of-the-art works from the literature.

  17. Cognitive Routing in Software-Defined Underwater Acoustic Networks

    Directory of Open Access Journals (Sweden)

    Huma Ghafoor

    2017-12-01

    Full Text Available There are two different types of primary users (natural acoustic and artificial acoustic, and there is a long propagation delay for acoustic links in underwater cognitive acoustic networks (UCANs. Thus, the selection of a stable route is one of the key design factors for improving overall network stability, thereby reducing end-to-end delay. Software-defined networking (SDN is a novel approach that improves network intelligence. To this end, we propose a novel SDN-based routing protocol for UCANs in order to find a stable route between source and destination. A main controller is placed in a surface buoy that is responsible for the global view of the network, whereas local controllers are placed in different autonomous underwater vehicles (AUVs that are responsible for a localized view of the network. The AUVs have fixed trajectories, and sensor nodes within transmission range of the AUVs serve as gateways to relay the gathered information to the controllers. This is an SDN-based underwater communications scheme whereby two nodes can only communicate when they have a consensus about a common idle channel. To evaluate our proposed scheme, we perform extensive simulations and improve network performance in terms of end-to-end delay, delivery ratio, and overhead.

  18. Critical field measurements in a superconducting networks

    International Nuclear Information System (INIS)

    Pannetier, B.; Chaussy, J.; Rammal, R.

    1984-01-01

    We have measured the critical field of a periodic two-dimensional network of superconducting indium. At low fields, the critical line Hsub(c)(T) reflects the network topology and exhibits well-defined cusps due to flux quantization corresponding to both integer and rational number of flux quanta phi 0 = h/2e per unit loop of the network [fr

  19. Research Network of Tehran Defined Population: Methodology and Establishment

    Directory of Open Access Journals (Sweden)

    Ali-Asghar Kolahi

    2015-12-01

    Full Text Available Background: We need a defined population for determining prevalence and incidence of diseases, as well as conducting interventional, cohort and longitudinal studies, calculating correct and timely public health indicators, assessing actual health needs of community, performing educational programs and interventions to promote healthy lifestyle, and enhancing quality of primary health services.The objective of this project was to determine a defined population which is representative of Tehran, the Capital of Iran. This article reports the methodology and establishment of the research network of Tehran defined population.Methods: This project started by selecting two urban health centers from each of the five district health centers affiliated to Shahid Beheshti University of Medical Sciences in 2012. Inside each selected urban health center, one defined population research station was established. Two new centers have been added during 2013 and 2014. For the time being, the number of the covered population of the network has reached 40000 individuals. The most important criterion for the defined population has been to be representative of the population of Tehran. For this, we selected two urban health centers from 12 of 22 municipality districts and from each of the five different socioeconomic of Greater Tehran. Merely 80000 individuals in neighborhoods of each defined population research station were considered as control group of the project.Findings: Totally we selected 12 defined population research stations and their under-covered population developed a defined population which is representative of Tehran population.Conclusion: a population lab is ready now in metropolitan of Tehran.

  20. Software Defined Network Monitoring Scheme Using Spectral Graph Theory and Phantom Nodes

    Science.gov (United States)

    2014-09-01

    networks is the emergence of software - defined networking ( SDN ) [1]. SDN has existed for the...Chapter III for network monitoring. A. SOFTWARE DEFINED NETWORKS SDNs provide a new and innovative method to simplify network hardware by logically...and R. Giladi, “Performance analysis of software - defined networking ( SDN ),” in Proc. of IEEE 21st International Symposium on Modeling, Analysis

  1. Hierarchy Measure for Complex Networks

    Science.gov (United States)

    Mones, Enys; Vicsek, Lilla; Vicsek, Tamás

    2012-01-01

    Nature, technology and society are full of complexity arising from the intricate web of the interactions among the units of the related systems (e.g., proteins, computers, people). Consequently, one of the most successful recent approaches to capturing the fundamental features of the structure and dynamics of complex systems has been the investigation of the networks associated with the above units (nodes) together with their relations (edges). Most complex systems have an inherently hierarchical organization and, correspondingly, the networks behind them also exhibit hierarchical features. Indeed, several papers have been devoted to describing this essential aspect of networks, however, without resulting in a widely accepted, converging concept concerning the quantitative characterization of the level of their hierarchy. Here we develop an approach and propose a quantity (measure) which is simple enough to be widely applicable, reveals a number of universal features of the organization of real-world networks and, as we demonstrate, is capable of capturing the essential features of the structure and the degree of hierarchy in a complex network. The measure we introduce is based on a generalization of the m-reach centrality, which we first extend to directed/partially directed graphs. Then, we define the global reaching centrality (GRC), which is the difference between the maximum and the average value of the generalized reach centralities over the network. We investigate the behavior of the GRC considering both a synthetic model with an adjustable level of hierarchy and real networks. Results for real networks show that our hierarchy measure is related to the controllability of the given system. We also propose a visualization procedure for large complex networks that can be used to obtain an overall qualitative picture about the nature of their hierarchical structure. PMID:22470477

  2. APIs for QoS configuration in Software Defined Networks

    DEFF Research Database (Denmark)

    Caba, Cosmin Marius; Soler, José

    2015-01-01

    The OpenFlow (OF) protocol is widely used in Software Defined Networking (SDN) to realize the communication between the controller and forwarding devices. OF allows great flexibility in managing traffic flows. However, OF alone is not enough to build more complex SDN services that require complete...... such as configuration of devices, ports, queues, etc. An Application Programming Interface (API) for dynamic configuration of QoS resources in the network devices is implemented herein, by using the capabilities of OVSDB. Further, the paper demonstrates the possibility to create network services with coarse granularity...... on top of the fine granular services exposed by the QoS configuration API at the SDNC. A series of tests emphasize the capabilities and the performance of the implemented QoS configuration API....

  3. Organization of Multi-controller Interaction in Software Defined Networks

    Directory of Open Access Journals (Sweden)

    Sergey V. Morzhov

    2018-01-01

    Full Text Available Software Defined Networking (SDN is a promising paradigm for network management. It is a centralized network intelligence on a dedicated server, which runs network operating system, and is called SDN controller. It was assumed that such an architecture should have an improved network performance and monitoring. However, the centralized control architecture of the SDNs brings novel challenges to reliability, scalability, fault tolerance and interoperability. These problems are especially acute for large data center networks and can be solved by combining SDN controllers into clusters, called multi-controllers. Multi-controller architecture became very important for SDN-enabled networks nowadays. This paper gives a comprehensive overview of SDN multi-controller architectures. The authors review several most popular distributed controllers in order to indicate their strengths and weaknesses. They also investigate and classify approaches used. This paper explains in details the difference among various types of multi-controller architectures, the distribution method and the communication system. Furthermore, it provides already implemented architectures and some examples of architectures under consideration by describing their design, communication process, and performance results. In this paper, the authors show their own classification of multi-controllers and claim that, despite the existence of undeniable advantages, all reviewed controllers have serious drawbacks, which must be eliminated. These drawbacks hamper the development of multi-controllers and their widespread adoption in corporate networks. In the end, the authors conclude that now it is impossible to find a solution capable to solve all the tasks assigned to it adequately and fully. The article is published in the authors’ wording.

  4. An Initial Load-Based Green Software Defined Network

    Directory of Open Access Journals (Sweden)

    Ying Hu

    2017-05-01

    Full Text Available Software defined network (SDN is a new network architecture in which the control function is decoupled from the data forwarding plane, that is attracting wide attentions from both research and industry sectors. However, SDN still faces the energy waste problem as do traditional networks. At present, research on energy saving in SDN is mainly focused on the static optimization of the network with zero load when new traffic arrives, changing the transmission path of the uncompleted traffic which arrived before the optimization, possibly resulting in route oscillation and other deleterious effects. To avoid this, a dynamical energy saving optimization scheme in which the paths of the uncompleted flows will not be changed when new traffic arrives is designed. To find the optimal solution for energy saving, the problem is modeled as a mixed integer linear programming (MILP problem. As the high complexity of the problem prohibits the optimal solution, an improved heuristic routing algorithm called improved constant weight greedy algorithm (ICWGA is proposed to find a sub-optimal solution. Simulation results show that the energy saving capacity of ICWGA is close to that of the optimal solution, offering desirable improvement in the energy efficiency of the network.

  5. Towards Effective Intra-flow Network Coding in Software Defined Wireless Mesh Networks

    OpenAIRE

    Donghai Zhu; Xinyu Yang Yang; Peng Zhao; Wei Yu

    2016-01-01

    Wireless Mesh Networks (WMNs) have potential to provide convenient broadband wireless Internet access to mobile users.With the support of Software-Defined Networking (SDN) paradigm that separates control plane and data plane, WMNs can be easily deployed and managed. In addition, by exploiting the broadcast nature of the wireless medium and the spatial diversity of multi-hop wireless networks, intra-flow network coding has shown a greater benefit in comparison with traditional routing paradigm...

  6. Software-Defined Networks as a Stage of the Network Technology Evolution

    Directory of Open Access Journals (Sweden)

    A. A. Krasotin

    2013-01-01

    Full Text Available The authors of the article focus on the concept of a software defined network. In the beginning, the brief historical account is given concerning software defined networks as a scientific concept, its formation and technological and scientific meaning. The software defined network concept is treated in the article not as the final state-of-the-art in networking, but rather as a possible step and direction in the development of a networking paradigm. The article touches on pros and cons as well of the software defined networking and gives an account of possible stages of development of this technology in the context of other technologies, considering its hybrid with MPLS, as an example. OpenFlow protocol constitutes the main part of the article. The authors further discuss various kinds of existing libraries realizing programmable management routines for a software defined network using OpenFlow. All of these libraries provide API for building modular applications for software defined network management. Touching on practical side of implementation the results of comparative tests of throughput and latency, achieved with these libraries are shown.

  7. Resilient Disaster Network Based on Software Defined Cognitive Wireless Network Technology

    Directory of Open Access Journals (Sweden)

    Goshi Sato

    2015-01-01

    Full Text Available In order to temporally recover the information network infrastructure in disaster areas from the Great East Japan Earthquake in 2011, various wireless network technologies such as satellite IP network, 3G, and Wi-Fi were effectively used. However, since those wireless networks are individually introduced and installed but not totally integrated, some of networks were congested due to the sudden network traffic generation and unbalanced traffic distribution, and eventually the total network could not effectively function. In this paper, we propose a disaster resilient network which integrates various wireless networks into a cognitive wireless network that users can use as an access network to the Internet at the serious disaster occurrence. We designed and developed the disaster resilient network based on software defined network (SDN technology to automatically select the best network link and route among the possible access networks to the Internet by periodically monitoring their network states and evaluate those using extended AHP method. In order to verify the usefulness of our proposed system, a prototype system is constructed and its performance is evaluated.

  8. Optimal Switch Configuration in Software-Defined Networks

    Directory of Open Access Journals (Sweden)

    Béla GENGE

    2016-06-01

    Full Text Available The emerging Software-Defined Networks (SDN paradigm facilitates innovative applications and enables the seamless provisioning of resilient communications. Nevertheless, the installation of communication flows in SDN requires careful planning in order to avoid configuration errors and to fulfill communication requirements. In this paper we propose an approach that installs automatically and optimally static flows in SDN switches. The approach aims to select high capacity links and shortest path routing, and enforces communication link and switch capacity limitations. Experimental results demonstrate the effectiveness and scalability of the developed methodology.

  9. Software-defined network abstractions and configuration interfaces for building programmable quantum networks

    Energy Technology Data Exchange (ETDEWEB)

    Dasari, Venkat [U.S. Army Research Laboratory, Aberdeen Proving Ground, MD; Sadlier, Ronald J [ORNL; Geerhart, Mr. Billy [U.S. Army Research Laboratory, Aberdeen Proving Ground, MD; Snow, Nikolai [U.S. Army Research Laboratory, Aberdeen Proving Ground, MD; Williams, Brian P [ORNL; Humble, Travis S [ORNL

    2017-01-01

    Well-defined and stable quantum networks are essential to realize functional quantum applications. Quantum networks are complex and must use both quantum and classical channels to support quantum applications like QKD, teleportation, and superdense coding. In particular, the no-cloning theorem prevents the reliable copying of quantum signals such that the quantum and classical channels must be highly coordinated using robust and extensible methods. We develop new network abstractions and interfaces for building programmable quantum networks. Our approach leverages new OpenFlow data structures and table type patterns to build programmable quantum networks and to support quantum applications.

  10. New value added to network services through software-defined optical core networking

    Science.gov (United States)

    Yamada, Akiko; Nakatsugawa, Keiichi; Yamashita, Shinji; Soumiya, Toshio

    2016-02-01

    If an optical core network can be handled flexibly, it can be used not only as network infrastructure but also as a temporary broadband resource when customers have to transfer a large volume of data quickly, which will in turn lead to new WAN services. We propose "software-defined optical core networking", which achieves flexible optical network control, meaning it virtualizes optical transport network/wavelength-division multiplexing resources and controls them with resources from other layers, such as Ether/MPLS. We developed a testbed system and verified that users could request broadband resources easily, and our controller could quickly set up an optical channel data unit path for the request.

  11. Software-Defined Collaborative Offloading for Heterogeneous Vehicular Networks

    Directory of Open Access Journals (Sweden)

    Wei Quan

    2018-01-01

    Full Text Available Vehicle-assisted data offloading is envisioned to significantly alleviate the problem of explosive growth of mobile data traffic. However, due to the high mobility of vehicles and the frequent disruption of communication links, it is very challenging to efficiently optimize collaborative offloading from a group of vehicles. In this paper, we leverage the concept of Software-Defined Networking (SDN and propose a software-defined collaborative offloading (SDCO solution for heterogeneous vehicular networks. In particular, SDCO can efficiently manage the offloading nodes and paths based on a centralized offloading controller. The offloading controller is equipped with two specific functions: the hybrid awareness path collaboration (HPC and the graph-based source collaboration (GSC. HPC is in charge of selecting the suitable paths based on the round-trip time, packet loss rate, and path bandwidth, while GSC optimizes the offloading nodes according to the minimum vertex cover for effective offloading. Simulation results are provided to demonstrate that SDCO can achieve better offloading efficiency compared to the state-of-the-art solutions.

  12. Security Awareness in Software-Defined Multi-Domain 5G Networks

    Directory of Open Access Journals (Sweden)

    Jani Suomalainen

    2018-03-01

    Full Text Available Fifth generation (5G technologies will boost the capacity and ease the management of mobile networks. Emerging virtualization and softwarization technologies enable more flexible customization of network services and facilitate cooperation between different actors. However, solutions are needed to enable users, operators, and service providers to gain an up-to-date awareness of the security and trustworthiness of 5G systems. We describe a novel framework and enablers for security monitoring, inferencing, and trust measuring. The framework leverages software-defined networking and big data technologies to customize monitoring for different applications. We present an approach for sharing security measurements across administrative domains. We describe scenarios where the correlation of multi-domain information improves the accuracy of security measures with respect to two threats: end-user location tracking and Internet of things (IoT authentication storms. We explore the security characteristics of data flows in software networks dedicated to different applications with a mobile network testbed.

  13. Federated software defined network operations for LHC experiments

    Science.gov (United States)

    Kim, Dongkyun; Byeon, Okhwan; Cho, Kihyeon

    2013-09-01

    The most well-known high-energy physics collaboration, the Large Hadron Collider (LHC), which is based on e-Science, has been facing several challenges presented by its extraordinary instruments in terms of the generation, distribution, and analysis of large amounts of scientific data. Currently, data distribution issues are being resolved by adopting an advanced Internet technology called software defined networking (SDN). Stability of the SDN operations and management is demanded to keep the federated LHC data distribution networks reliable. Therefore, in this paper, an SDN operation architecture based on the distributed virtual network operations center (DvNOC) is proposed to enable LHC researchers to assume full control of their own global end-to-end data dissemination. This may achieve an enhanced data delivery performance based on data traffic offloading with delay variation. The evaluation results indicate that the overall end-to-end data delivery performance can be improved over multi-domain SDN environments based on the proposed federated SDN/DvNOC operation framework.

  14. Urban Green Network Design: Defining green network from an urban planning perspective

    OpenAIRE

    Andrea Tulisi

    2017-01-01

    From the theoretical context of Smart City various studies have emerged that adopt an analytical approach and description of urban phenomena based on the principles of “network design”; this line of research uses the network systems theory to define the principles that regulate the relationships among the various elements of urban sub-systems in order to optimize their functionality. From the same theoretical basis, urban greenspaces have also been studied as networks, by means of the creatio...

  15. On the Tradeoff between Performance and Programmability for Software Defined WiFi Networks

    Directory of Open Access Journals (Sweden)

    Tausif Zahid

    2018-01-01

    Full Text Available WiFi has become one of the major network access networks due to its simple technical implementation and high-bandwidth provisioning. In this paper, we studied software defined WiFi networks (SDWN against traditional WiFi networks to understand the potential benefits, such as the ability of SDWN to effectively hide the handover delay between access points (AP of the adoption of the SDWN architecture on WiFi networks and identify representative application scenarios where such SDWN approach could bring additional benefits. This study delineated the performance bottlenecks such as the throughput degradation by around 50% compared with the conventional WiFi networks. In addition, our study also shed some insights into performance optimization issues. All of the performance measurements were conducted on a network testbed consisting of a single basic service set (BSS and an extended service set (ESS managed by a single SDN controller deployed with various laboratory settings. Our evaluation included the throughput performance under different traffic loads with different number of nodes and packet sizes for both TCP and UDP traffic flows. Handover delays were measured during the roaming phase between different APs against the traditional WiFi networks. Our results have demonstrated the tradeoff between performance and programmability of software defined APs.

  16. Malware Propagation and Prevention Model for Time-Varying Community Networks within Software Defined Networks

    Directory of Open Access Journals (Sweden)

    Lan Liu

    2017-01-01

    Full Text Available As the adoption of Software Defined Networks (SDNs grows, the security of SDN still has several unaddressed limitations. A key network security research area is in the study of malware propagation across the SDN-enabled networks. To analyze the spreading processes of network malware (e.g., viruses in SDN, we propose a dynamic model with a time-varying community network, inspired by research models on the spread of epidemics in complex networks across communities. We assume subnets of the network as communities and links that are dense in subnets but sparse between subnets. Using numerical simulation and theoretical analysis, we find that the efficiency of network malware propagation in this model depends on the mobility rate q of the nodes between subnets. We also find that there exists a mobility rate threshold qc. The network malware will spread in the SDN when the mobility rate q>qc. The malware will survive when q>qc and perish when qnetwork malware and provide a theoretical basis to reduce and prevent network security incidents.

  17. 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...... and enable wider areas' energy efficiency networking. The energy related information of the networks and the types of the traffic flows are collected and utilized for the end-to-end QoS provision. Dynamic network simulation results show that by applying different routing algorithms according to the type...... of traffic in the core networks, the energy efficiency of the network is improved without compromising the quality of service....

  18. In-network adaptation of SHVC video in software-defined networks

    Science.gov (United States)

    Awobuluyi, Olatunde; Nightingale, James; Wang, Qi; Alcaraz Calero, Jose Maria; Grecos, Christos

    2016-04-01

    Software Defined Networks (SDN), when combined with Network Function Virtualization (NFV) represents a paradigm shift in how future networks will behave and be managed. SDN's are expected to provide the underpinning technologies for future innovations such as 5G mobile networks and the Internet of Everything. The SDN architecture offers features that facilitate an abstracted and centralized global network view in which packet forwarding or dropping decisions are based on application flows. Software Defined Networks facilitate a wide range of network management tasks, including the adaptation of real-time video streams as they traverse the network. SHVC, the scalable extension to the recent H.265 standard is a new video encoding standard that supports ultra-high definition video streams with spatial resolutions of up to 7680×4320 and frame rates of 60fps or more. The massive increase in bandwidth required to deliver these U-HD video streams dwarfs the bandwidth requirements of current high definition (HD) video. Such large bandwidth increases pose very significant challenges for network operators. In this paper we go substantially beyond the limited number of existing implementations and proposals for video streaming in SDN's all of which have primarily focused on traffic engineering solutions such as load balancing. By implementing and empirically evaluating an SDN enabled Media Adaptation Network Entity (MANE) we provide a valuable empirical insight into the benefits and limitations of SDN enabled video adaptation for real time video applications. The SDN-MANE is the video adaptation component of our Video Quality Assurance Manager (VQAM) SDN control plane application, which also includes an SDN monitoring component to acquire network metrics and a decision making engine using algorithms to determine the optimum adaptation strategy for any real time video application flow given the current network conditions. Our proposed VQAM application has been implemented and

  19. Software Defined Networking (SDN) controlled all optical switching networks with multi-dimensional switching architecture

    Science.gov (United States)

    Zhao, Yongli; Ji, Yuefeng; Zhang, Jie; Li, Hui; Xiong, Qianjin; Qiu, Shaofeng

    2014-08-01

    Ultrahigh throughout capacity requirement is challenging the current optical switching nodes with the fast development of data center networks. Pbit/s level all optical switching networks need to be deployed soon, which will cause the high complexity of node architecture. How to control the future network and node equipment together will become a new problem. An enhanced Software Defined Networking (eSDN) control architecture is proposed in the paper, which consists of Provider NOX (P-NOX) and Node NOX (N-NOX). With the cooperation of P-NOX and N-NOX, the flexible control of the entire network can be achieved. All optical switching network testbed has been experimentally demonstrated with efficient control of enhanced Software Defined Networking (eSDN). Pbit/s level all optical switching nodes in the testbed are implemented based on multi-dimensional switching architecture, i.e. multi-level and multi-planar. Due to the space and cost limitation, each optical switching node is only equipped with four input line boxes and four output line boxes respectively. Experimental results are given to verify the performance of our proposed control and switching architecture.

  20. Towards Effective Intra-flow Network Coding in Software Defined Wireless Mesh Networks

    Directory of Open Access Journals (Sweden)

    Donghai Zhu

    2016-01-01

    Full Text Available Wireless Mesh Networks (WMNs have potential to provide convenient broadband wireless Internet access to mobile users.With the support of Software-Defined Networking (SDN paradigm that separates control plane and data plane, WMNs can be easily deployed and managed. In addition, by exploiting the broadcast nature of the wireless medium and the spatial diversity of multi-hop wireless networks, intra-flow network coding has shown a greater benefit in comparison with traditional routing paradigms in data transmission for WMNs. In this paper, we develop a novel OpenCoding protocol, which combines the SDN technique with intra-flow network coding for WMNs. Our developed protocol can simplify the deployment and management of the network and improve network performance. In OpenCoding, a controller that works on the control plane makes routing decisions for mesh routers and the hop-by-hop forwarding function is replaced by network coding functions in data plane. We analyze the overhead of OpenCoding. Through a simulation study, we show the effectiveness of the OpenCoding protocol in comparison with existing schemes. Our data shows that OpenCoding outperforms both traditional routing and intra-flow network coding schemes.

  1. Experimental performance evaluation of software defined networking (SDN) based data communication networks for large scale flexi-grid optical networks.

    Science.gov (United States)

    Zhao, Yongli; He, Ruiying; Chen, Haoran; Zhang, Jie; Ji, Yuefeng; Zheng, Haomian; Lin, Yi; Wang, Xinbo

    2014-04-21

    Software defined networking (SDN) has become the focus in the current information and communication technology area because of its flexibility and programmability. It has been introduced into various network scenarios, such as datacenter networks, carrier networks, and wireless networks. Optical transport network is also regarded as an important application scenario for SDN, which is adopted as the enabling technology of data communication networks (DCN) instead of general multi-protocol label switching (GMPLS). However, the practical performance of SDN based DCN for large scale optical networks, which is very important for the technology selection in the future optical network deployment, has not been evaluated up to now. In this paper we have built a large scale flexi-grid optical network testbed with 1000 virtual optical transport nodes to evaluate the performance of SDN based DCN, including network scalability, DCN bandwidth limitation, and restoration time. A series of network performance parameters including blocking probability, bandwidth utilization, average lightpath provisioning time, and failure restoration time have been demonstrated under various network environments, such as with different traffic loads and different DCN bandwidths. The demonstration in this work can be taken as a proof for the future network deployment.

  2. Operationalization of Software-Defined Networks (SDN) Program Review

    Data.gov (United States)

    Networking and Information Technology Research and Development, Executive Office of the President — U.S. federal investments in networking research and technologies deployment have fostered and accelerated the development of the Internet from its inception. It is...

  3. Dynamic optical resource allocation for mobile core networks with software defined elastic optical networking.

    Science.gov (United States)

    Zhao, Yongli; Chen, Zhendong; Zhang, Jie; Wang, Xinbo

    2016-07-25

    Driven by the forthcoming of 5G mobile communications, the all-IP architecture of mobile core networks, i.e. evolved packet core (EPC) proposed by 3GPP, has been greatly challenged by the users' demands for higher data rate and more reliable end-to-end connection, as well as operators' demands for low operational cost. These challenges can be potentially met by software defined optical networking (SDON), which enables dynamic resource allocation according to the users' requirement. In this article, a novel network architecture for mobile core network is proposed based on SDON. A software defined network (SDN) controller is designed to realize the coordinated control over different entities in EPC networks. We analyze the requirement of EPC-lightpath (EPCL) in data plane and propose an optical switch load balancing (OSLB) algorithm for resource allocation in optical layer. The procedure of establishment and adjustment of EPCLs is demonstrated on a SDON-based EPC testbed with extended OpenFlow protocol. We also evaluate the OSLB algorithm through simulation in terms of bandwidth blocking ratio, traffic load distribution, and resource utilization ratio compared with link-based load balancing (LLB) and MinHops algorithms.

  4. Performance verification of network function virtualization in software defined optical transport networks

    Science.gov (United States)

    Zhao, Yongli; Hu, Liyazhou; Wang, Wei; Li, Yajie; Zhang, Jie

    2017-01-01

    With the continuous opening of resource acquisition and application, there are a large variety of network hardware appliances deployed as the communication infrastructure. To lunch a new network application always implies to replace the obsolete devices and needs the related space and power to accommodate it, which will increase the energy and capital investment. Network function virtualization1 (NFV) aims to address these problems by consolidating many network equipment onto industry standard elements such as servers, switches and storage. Many types of IT resources have been deployed to run Virtual Network Functions (vNFs), such as virtual switches and routers. Then how to deploy NFV in optical transport networks is a of great importance problem. This paper focuses on this problem, and gives an implementation architecture of NFV-enabled optical transport networks based on Software Defined Optical Networking (SDON) with the procedure of vNFs call and return. Especially, an implementation solution of NFV-enabled optical transport node is designed, and a parallel processing method for NFV-enabled OTN nodes is proposed. To verify the performance of NFV-enabled SDON, the protocol interaction procedures of control function virtualization and node function virtualization are demonstrated on SDON testbed. Finally, the benefits and challenges of the parallel processing method for NFV-enabled OTN nodes are simulated and analyzed.

  5. Security Analysis of a Software Defined Wide Area Network Solution

    OpenAIRE

    Rajendran, Ashok

    2016-01-01

    Enterprise wide area network (WAN) is a private network that connects the computers and other devices across an organisation's branch locations and the data centers. It forms the backbone of enterprise communication. Currently, multiprotocol label switching (MPLS) is commonly used to provide this service. As a recent alternative to MPLS, software-dened wide area networking (SD-WAN) solutions are being introduced as an IP based cloud-networking service for enterprises. SD-WAN virtualizes the n...

  6. On the Update Problems for Software Defined Networks

    Directory of Open Access Journals (Sweden)

    V. A. Zakharov

    2014-01-01

    Full Text Available The designing of network update algorithms is urgent for the development of SDN control software. A particular case of Network Update Problem is that of restoring seamlessly a given network configuration after some packet forwarding rules have been disabled (say, at the expiry of their time-outs. We study this problem in the framework of a formal model of SDN, develop correct and safe network recovering algorithms, and show that in general case there is no way to restore network configuration seamlessly without referring to priorities of packet forwarding rules.

  7. Towards a distributed control system for software defined wireless sensor networks

    CSIR Research Space (South Africa)

    Kobo, Hlabishi I

    2017-10-01

    Full Text Available on the network device. The coupling stifles innovation and evolution because the network often becomes rigid. Software Defined Wireless Sensor Networks (SDWSN) is also an emerging network paradigm that infuses the SDN model into Wireless Sensor Networks (WSNs...

  8. Software Defined Networking for Next Generation Converged Metro-Access Networks

    Science.gov (United States)

    Ruffini, M.; Slyne, F.; Bluemm, C.; Kitsuwan, N.; McGettrick, S.

    2015-12-01

    While the concept of Software Defined Networking (SDN) has seen a rapid deployment within the data center community, its adoption in telecommunications network has progressed slowly, although the concept has been swiftly adopted by all major telecoms vendors. This paper presents a control plane architecture for SDN-driven converged metro-access networks, developed through the DISCUS European FP7 project. The SDN-based controller architecture was developed in a testbed implementation targeting two main scenarios: fast feeder fiber protection over dual-homed Passive Optical Networks (PONs) and dynamic service provisioning over a multi-wavelength PON. Implementation details and results of the experiment carried out over the second scenario are reported in the paper, showing the potential of SDN in providing assured on-demand services to end-users.

  9. Instantiating a Global Network Measurement Framework

    Energy Technology Data Exchange (ETDEWEB)

    Tierney, Brian L.; Boote, Jeff; Boyd, Eric; Brown, Aaron; Grigoriev, Maxim; Metzger, Joe; Swany, Martin; Zekauskas, Matt; Zurawski, Jason

    2008-12-15

    perfSONAR is a web services-based infrastructure for collecting and publishing network performance monitoring. A primary goal of perfSONAR is making it easier to solve end-to-end performance problems on paths crossing several networks. It contains a set of services delivering performance measurements in a federated environment. These services act as an intermediate layer, between the performance measurement tools and the diagnostic or visualization applications. This layer is aimed at making and exchanging performance measurements across multiple networks and multiple user communities, using well-defined protocols. This paper summarizes the key perfSONAR components, and describes how they are deployed by the US-LHC community to monitor the networks distributing LHC data from CERN. All monitoring data described herein is publicly available, and we hope the availability of this data via a standard schema will inspire others to contribute to the effort by building network data analysis applications that use perfSONAR.

  10. An Optimal Path Computation Architecture for the Cloud-Network on Software-Defined Networking

    Directory of Open Access Journals (Sweden)

    Hyunhun Cho

    2015-05-01

    Full Text Available Legacy networks do not open the precise information of the network domain because of scalability, management and commercial reasons, and it is very hard to compute an optimal path to the destination. According to today’s ICT environment change, in order to meet the new network requirements, the concept of software-defined networking (SDN has been developed as a technological alternative to overcome the limitations of the legacy network structure and to introduce innovative concepts. The purpose of this paper is to propose the application that calculates the optimal paths for general data transmission and real-time audio/video transmission, which consist of the major services of the National Research & Education Network (NREN in the SDN environment. The proposed SDN routing computation (SRC application is designed and applied in a multi-domain network for the efficient use of resources, selection of the optimal path between the multi-domains and optimal establishment of end-to-end connections.

  11. A Security Assessment Mechanism for Software-Defined Networking-Based Mobile Networks

    Directory of Open Access Journals (Sweden)

    Shibo Luo

    2015-12-01

    Full Text Available Software-Defined Networking-based Mobile Networks (SDN-MNs are considered the future of 5G mobile network architecture. With the evolving cyber-attack threat, security assessments need to be performed in the network management. Due to the distinctive features of SDN-MNs, such as their dynamic nature and complexity, traditional network security assessment methodologies cannot be applied directly to SDN-MNs, and a novel security assessment methodology is needed. In this paper, an effective security assessment mechanism based on attack graphs and an Analytic Hierarchy Process (AHP is proposed for SDN-MNs. Firstly, this paper discusses the security assessment problem of SDN-MNs and proposes a methodology using attack graphs and AHP. Secondly, to address the diversity and complexity of SDN-MNs, a novel attack graph definition and attack graph generation algorithm are proposed. In order to quantify security levels, the Node Minimal Effort (NME is defined to quantify attack cost and derive system security levels based on NME. Thirdly, to calculate the NME of an attack graph that takes the dynamic factors of SDN-MN into consideration, we use AHP integrated with the Technique for Order Preference by Similarity to an Ideal Solution (TOPSIS as the methodology. Finally, we offer a case study to validate the proposed methodology. The case study and evaluation show the advantages of the proposed security assessment mechanism.

  12. A Security Assessment Mechanism for Software-Defined Networking-Based Mobile Networks.

    Science.gov (United States)

    Luo, Shibo; Dong, Mianxiong; Ota, Kaoru; Wu, Jun; Li, Jianhua

    2015-12-17

    Software-Defined Networking-based Mobile Networks (SDN-MNs) are considered the future of 5G mobile network architecture. With the evolving cyber-attack threat, security assessments need to be performed in the network management. Due to the distinctive features of SDN-MNs, such as their dynamic nature and complexity, traditional network security assessment methodologies cannot be applied directly to SDN-MNs, and a novel security assessment methodology is needed. In this paper, an effective security assessment mechanism based on attack graphs and an Analytic Hierarchy Process (AHP) is proposed for SDN-MNs. Firstly, this paper discusses the security assessment problem of SDN-MNs and proposes a methodology using attack graphs and AHP. Secondly, to address the diversity and complexity of SDN-MNs, a novel attack graph definition and attack graph generation algorithm are proposed. In order to quantify security levels, the Node Minimal Effort (NME) is defined to quantify attack cost and derive system security levels based on NME. Thirdly, to calculate the NME of an attack graph that takes the dynamic factors of SDN-MN into consideration, we use AHP integrated with the Technique for Order Preference by Similarity to an Ideal Solution (TOPSIS) as the methodology. Finally, we offer a case study to validate the proposed methodology. The case study and evaluation show the advantages of the proposed security assessment mechanism.

  13. Implementing Resource-aware Multicast Forwarding in Software Defined Networks

    DEFF Research Database (Denmark)

    Poderys, Justas; Sunny, Anjusha; Soler, José

    2018-01-01

    Using multicast data transmissions, data can be eciently distributed to a high number of network users. However, in order to ef-ciently stream multimedia using multicast communication, multicast routing protocols must have knowledge of all network links and their available bandwidth. In Software......-Karp algorithm, by taking into account network topology and links load information. This paper presents the algorithm, implementation details, and an analysis of the testing results....

  14. Failure mitigation in software defined networking employing load type prediction

    KAUST Repository

    Bouacida, Nader; Alghadhban, Amer Mohammad JarAlla; Alalmaei, Shiyam Mohammed Abdullah; Mohammed, Haneen; Shihada, Basem

    2017-01-01

    The controller is a critical piece of the SDN architecture, where it is considered as the mastermind of SDN networks. Thus, its failure will cause a significant portion of the network to fail. Overload is one of the common causes of failure since

  15. Implementing Resource-aware Multicast Forwarding in Software Defined Networks

    DEFF Research Database (Denmark)

    Poderys, Justas; Sunny, Anjusha; Soler, José

    2018-01-01

    Using multicast data transmissions, data can be eciently distributed to a high number of network users. However, in order to ef-ciently stream multimedia using multicast communication, multicast routing protocols must have knowledge of all network links and their available bandwidth. In Software...

  16. Cross-layer restoration with software defined networking based on IP over optical transport networks

    Science.gov (United States)

    Yang, Hui; Cheng, Lei; Deng, Junni; Zhao, Yongli; Zhang, Jie; Lee, Young

    2015-10-01

    The IP over optical transport network is a very promising networking architecture applied to the interconnection of geographically distributed data centers due to the performance guarantee of low delay, huge bandwidth and high reliability at a low cost. It can enable efficient resource utilization and support heterogeneous bandwidth demands in highly-available, cost-effective and energy-effective manner. In case of cross-layer link failure, to ensure a high-level quality of service (QoS) for user request after the failure becomes a research focus. In this paper, we propose a novel cross-layer restoration scheme for data center services with software defined networking based on IP over optical network. The cross-layer restoration scheme can enable joint optimization of IP network and optical network resources, and enhance the data center service restoration responsiveness to the dynamic end-to-end service demands. We quantitatively evaluate the feasibility and performances through the simulation under heavy traffic load scenario in terms of path blocking probability and path restoration latency. Numeric results show that the cross-layer restoration scheme improves the recovery success rate and minimizes the overall recovery time.

  17. A Preliminary Survey on the Security of Software-Defined Networks

    OpenAIRE

    Akbaş, Muhammet Fatih; Karaarslan, Enis; Güngör, Cengiz

    2016-01-01

    The number of devices connected to theInternet is increasing, data centers are growing continuously and computernetworks are getting more complex. Traditional network management approach isbecoming more difficult and insufficient. Software-Defined Networks (SDN) is anew generation networking approach which is expected to take place of thetraditional computer networks. SDN architecture provides effective managementof the large and complex networks. Although SDN have benefits from the network s...

  18. Fighting Networks: The Defining Challenge of Irregular Warfare

    Science.gov (United States)

    2011-06-01

    fighting networks, different skills allow for increased operational complexity. Lawrence and Lorsch found that organizations in more uncertain...Uncertainty in the Face of Risk,” in Cooperation and Prosocial Behavior, ed. Robert Hindle and Jo Groebel (New York: Cambridge University Press, 1991...simplistic to describe al-Qaeda as a guerrilla organization as they have transcended traditional practices by their skilled utilization of the network form

  19. Using Cognitive Control in Software Defined Networking for Port Scan Detection

    Science.gov (United States)

    2017-07-01

    ARL-TR-8059 ● July 2017 US Army Research Laboratory Using Cognitive Control in Software -Defined Networking for Port Scan...Cognitive Control in Software -Defined Networking for Port Scan Detection by Vinod K Mishra Computational and Information Sciences Directorate, ARL...Technical Report 3. DATES COVERED (From - To) 15 June–31 July 2016 4. TITLE AND SUBTITLE Using Cognitive Control in Software -Defined Networking for

  20. Software Defined Networking for Improved Wireless Sensor Network Management: A Survey.

    Science.gov (United States)

    Ndiaye, Musa; Hancke, Gerhard P; Abu-Mahfouz, Adnan M

    2017-05-04

    Wireless sensor networks (WSNs) are becoming increasingly popular with the advent of the Internet of things (IoT). Various real-world applications of WSNs such as in smart grids, smart farming and smart health would require a potential deployment of thousands or maybe hundreds of thousands of sensor nodes/actuators. To ensure proper working order and network efficiency of such a network of sensor nodes, an effective WSN management system has to be integrated. However, the inherent challenges of WSNs such as sensor/actuator heterogeneity, application dependency and resource constraints have led to challenges in implementing effective traditional WSN management. This difficulty in management increases as the WSN becomes larger. Software Defined Networking (SDN) provides a promising solution in flexible management WSNs by allowing the separation of the control logic from the sensor nodes/actuators. The advantage with this SDN-based management in WSNs is that it enables centralized control of the entire WSN making it simpler to deploy network-wide management protocols and applications on demand. This paper highlights some of the recent work on traditional WSN management in brief and reviews SDN-based management techniques for WSNs in greater detail while drawing attention to the advantages that SDN brings to traditional WSN management. This paper also investigates open research challenges in coming up with mechanisms for flexible and easier SDN-based WSN configuration and management.

  1. Software Defined Networking for Improved Wireless Sensor Network Management: A Survey

    Directory of Open Access Journals (Sweden)

    Musa Ndiaye

    2017-05-01

    Full Text Available Wireless sensor networks (WSNs are becoming increasingly popular with the advent of the Internet of things (IoT. Various real-world applications of WSNs such as in smart grids, smart farming and smart health would require a potential deployment of thousands or maybe hundreds of thousands of sensor nodes/actuators. To ensure proper working order and network efficiency of such a network of sensor nodes, an effective WSN management system has to be integrated. However, the inherent challenges of WSNs such as sensor/actuator heterogeneity, application dependency and resource constraints have led to challenges in implementing effective traditional WSN management. This difficulty in management increases as the WSN becomes larger. Software Defined Networking (SDN provides a promising solution in flexible management WSNs by allowing the separation of the control logic from the sensor nodes/actuators. The advantage with this SDN-based management in WSNs is that it enables centralized control of the entire WSN making it simpler to deploy network-wide management protocols and applications on demand. This paper highlights some of the recent work on traditional WSN management in brief and reviews SDN-based management techniques for WSNs in greater detail while drawing attention to the advantages that SDN brings to traditional WSN management. This paper also investigates open research challenges in coming up with mechanisms for flexible and easier SDN-based WSN configuration and management.

  2. Desenvolupament d'un sistema de monitoratge per a Software Defined Networks (SDN)

    OpenAIRE

    Navarro Sánchez, Albert

    2015-01-01

    Les Software Defined-Networks (SDN) són una tecnologia emergent que permet als components software estendre funcionalitats sobre la xarxa. En aquest projecte s'estudia com pot encaixar Polygraph, un sistema de monitoratge per a xarxes tradicionals, dins les SDN. Software Defined-Networks (SDN) are a new tecnology that allows software components to add new functionalities on networks. This project studies how Polygraph, a monitoring system for traditional networks, can fit in a SDN scenario.

  3. dSDiVN: a distributed Software-Defined Networking architecture for Infrastructure-less Vehicular Networks

    OpenAIRE

    Alioua, Ahmed; Senouci, Sidi-Mohammed; Moussaoui, Samira

    2017-01-01

    In the last few years, the emerging network architecture paradigm of Software-Defined Networking (SDN), has become one of the most important technology to manage large scale networks such as Vehicular Ad-hoc Networks (VANETs). Recently, several works have shown interest in the use of SDN paradigm in VANETs. SDN brings flexibility, scalability and management facility to current VANETs. However, almost all of proposed Software-Defined VANET (SDVN) architectures are infrastructure-based. This pa...

  4. Robust and Agile System against Fault and Anomaly Traffic in Software Defined Networks

    Directory of Open Access Journals (Sweden)

    Mihui Kim

    2017-03-01

    Full Text Available The main advantage of software defined networking (SDN is that it allows intelligent control and management of networking though programmability in real time. It enables efficient utilization of network resources through traffic engineering, and offers potential attack defense methods when abnormalities arise. However, previous studies have only identified individual solutions for respective problems, instead of finding a more global solution in real time that is capable of addressing multiple situations in network status. To cover diverse network conditions, this paper presents a comprehensive reactive system for simultaneously monitoring failures, anomalies, and attacks for high availability and reliability. We design three main modules in the SDN controller for a robust and agile defense (RAD system against network anomalies: a traffic analyzer, a traffic engineer, and a rule manager. RAD provides reactive flow rule generation to control traffic while detecting network failures, anomalies, high traffic volume (elephant flows, and attacks. The traffic analyzer identifies elephant flows, traffic anomalies, and attacks based on attack signatures and network monitoring. The traffic engineer module measures network utilization and delay in order to determine the best path for multi-dimensional routing and load balancing under any circumstances. Finally, the rule manager generates and installs a flow rule for the selected best path to control traffic. We implement the proposed RAD system based on Floodlight, an open source project for the SDN controller. We evaluate our system using simulation with and without the aforementioned RAD modules. Experimental results show that our approach is both practical and feasible, and can successfully augment an existing SDN controller in terms of agility, robustness, and efficiency, even in the face of link failures, attacks, and elephant flows.

  5. Simulasi Virtual Local Area Network (VLAN Berbasis Software Defined Network (SDN Menggunakan POX Controller

    Directory of Open Access Journals (Sweden)

    Rohmat Tulloh

    2015-11-01

    Full Text Available VLAN (Virtual LAN merupakan sebuah teknologi yang dapat mengkonfigurasi jaringan logis independen dari struktur jaringan fisik. Hasil dari penelitian sebelumnya sudah diprediksi bahwa dibutuhkan Virtual Network yang akhirnya terciptalah VLAN. Namun paradigma jaringan saat ini tidak flexible, ketergantungan terhadap vendor sangat besar karena fungsi data plane dan control plane berada dalam satu paket device. SDN (Software defined network yang merupakan salahsatu evolusi teknologi jaringan sesuai dengan tuntutan yang berkembang dimana memisahkan fungsi data plane dan control plane pada suatu perangkat. POX Controller digunakan untuk men-simulasikan dan menguji Platform SDN (Software defined network. Pada penelitian ini menggunakan Openflow versi 1.0 untuk memasang header VLAN sehingga penelitian ini difokuskan untuk mengevaluasi performa forwarding VLAN yang memanfaatkan Openflow sebagai control plane dapat berfungsi dengan baik. Hasil penelitian ini mengusulkan penerapan karakteristik teknologi VLAN pada SDN karena telah berjalan dengan benar sesuai hasil pengujian konektifitas, verifikasi dan keamanan. Kemudian hasil pengujian lanjutan untuk melihat pengaruh SDN dengan skenario penambahan jumlah VLAN ID didapatkan bahwa set-up time akan bertambah seiring meningkatnya jumlah host dan dengan menggunakan protokol OpenFlow, latency yang terjadi di jaringan dapat dipantau dengan parameter round trip time (RTT yang stabil direntang 0,2 sampai 6 second walaupun jumlah vlan_id dan background traffic bertambah.

  6. Software Defined Optics and Networking for Large Scale Data Centers

    DEFF Research Database (Denmark)

    Mehmeri, Victor; Andrus, Bogdan-Mihai; Tafur Monroy, Idelfonso

    Big data imposes correlations of large amounts of information between numerous systems and databases. This leads to large dynamically changing flows and traffic patterns between clusters and server racks that result in a decrease of the quality of transmission and degraded application performance....... Highly interconnected topologies combined with flexible, on demand network configuration can become a solution to the ever-increasing dynamic traffic...

  7. Software defined networking to improve mobility management performance

    NARCIS (Netherlands)

    Karimzadeh Motallebi Azar, Morteza; Sperotto, Anna; Pras, Aiko; Sperotto, Anna; Doyen, Guillaume; Latré, Steven; Charalambides, Marinos; Stiller, Burkhard

    2014-01-01

    n mobile networks, efficient IP mobility management is a crucial issue for the mobile users changing their mobility anchor points during handover. In this regard several mobility management methods have been proposed. However, those are insufficient for the future mobile Internet in terms of

  8. Monitoring and Discovery for Self-Organized Network Management in Virtualized and Software Defined Networks

    Science.gov (United States)

    Valdivieso Caraguay, Ángel Leonardo; García Villalba, Luis Javier

    2017-01-01

    This paper presents the Monitoring and Discovery Framework of the Self-Organized Network Management in Virtualized and Software Defined Networks SELFNET project. This design takes into account the scalability and flexibility requirements needed by 5G infrastructures. In this context, the present framework focuses on gathering and storing the information (low-level metrics) related to physical and virtual devices, cloud environments, flow metrics, SDN traffic and sensors. Similarly, it provides the monitoring data as a generic information source in order to allow the correlation and aggregation tasks. Our design enables the collection and storing of information provided by all the underlying SELFNET sublayers, including the dynamically onboarded and instantiated SDN/NFV Apps, also known as SELFNET sensors. PMID:28362346

  9. Monitoring and Discovery for Self-Organized Network Management in Virtualized and Software Defined Networks.

    Science.gov (United States)

    Caraguay, Ángel Leonardo Valdivieso; Villalba, Luis Javier García

    2017-03-31

    This paper presents the Monitoring and Discovery Framework of the Self-Organized Network Management in Virtualized and Software Defined Networks SELFNET project. This design takes into account the scalability and flexibility requirements needed by 5G infrastructures. In this context, the present framework focuses on gathering and storing the information (low-level metrics) related to physical and virtual devices, cloud environments, flow metrics, SDN traffic and sensors. Similarly, it provides the monitoring data as a generic information source in order to allow the correlation and aggregation tasks. Our design enables the collection and storing of information provided by all the underlying SELFNET sublayers, including the dynamically onboarded and instantiated SDN/NFV Apps, also known as SELFNET sensors.

  10. Monitoring and Discovery for Self-Organized Network Management in Virtualized and Software Defined Networks

    Directory of Open Access Journals (Sweden)

    Ángel Leonardo Valdivieso Caraguay

    2017-03-01

    Full Text Available This paper presents the Monitoring and Discovery Framework of the Self-Organized Network Management in Virtualized and Software Defined Networks SELFNET project. This design takes into account the scalability and flexibility requirements needed by 5G infrastructures. In this context, the present framework focuses on gathering and storing the information (low-level metrics related to physical and virtual devices, cloud environments, flow metrics, SDN traffic and sensors. Similarly, it provides the monitoring data as a generic information source in order to allow the correlation and aggregation tasks. Our design enables the collection and storing of information provided by all the underlying SELFNET sublayers, including the dynamically onboarded and instantiated SDN/NFV Apps, also known as SELFNET sensors.

  11. Measurement of Online Social Networks

    Science.gov (United States)

    Gjoka, Mina

    2010-01-01

    In recent years, the popularity of online social networks (OSN) has risen to unprecedented levels, with the most popular ones having hundreds of millions of users. This success has generated interest within the networking community and has given rise to a number of measurement and characterization studies, which provide a first step towards their…

  12. Alpha emitters activity measurement using the defined solid angle method

    International Nuclear Information System (INIS)

    Blanchis, P.

    1983-01-01

    The defined solid angle counting method can reach a very high accuracy, specially for heavy ions as alpha particles emitted by a radioactive source. The activity measurement of such sources with a relative uncertainty of the order of 0.01% is investigated. Such an accuracy is available only under suitable conditions: the radiation emitted by the source must be isotropic and all the particles emitted in the effective solid angle must be detected. The efficiency detection value must be equal to unity and phenomena such as absorption or scattering must be null. It is shown that corrections often become necessary. All parameters which can influence the measurements are studied [fr

  13. Performance considerations of ultrasonic distance measurement with well defined properties

    International Nuclear Information System (INIS)

    Elmer, Hannes; Schweinzer, Herbert

    2005-01-01

    Conventional ultrasonic distance measurement systems based on narrow bandwidth ultrasonic bursts and amplitude detection are often used because of their low costs and easy implementation. However, the achievable results strongly depend on the actual environments where the system is implemented: in case of well defined objects that are always located near the measurement direction of the system, in general good results are obtained. If arbitrary objects are expected that are moreover located in arbitrary positions in front of the sensor, strongly object dependent areas where objects are detected with decreasing accuracy towards their borders must be taken into account. In previous works we developed an ultrasonic measurement system that provides accurate distance measurement values within a well defined detection area that is independent of the reflection properties of the objects. This measurement system is based on the One Bit Correlation method that is described in the following. To minimise its implementation efforts, it is necessary to examine the influence of the system parameters as e.g. the correlation length to the results that are expected in case of different signal to noise ratios of the received signal. In the following, these examinations are shown and the obtained results are discussed that allow getting a well conditioned system that makes best use of given system resources

  14. Failure mitigation in software defined networking employing load type prediction

    KAUST Repository

    Bouacida, Nader

    2017-07-31

    The controller is a critical piece of the SDN architecture, where it is considered as the mastermind of SDN networks. Thus, its failure will cause a significant portion of the network to fail. Overload is one of the common causes of failure since the controller is frequently invoked by new flows. Even through SDN controllers are often replicated, the significant recovery time can be an overkill for the availability of the entire network. In order to overcome the problem of the overloaded controller failure in SDN, this paper proposes a novel controller offload solution for failure mitigation based on a prediction module that anticipates the presence of a harmful long-term load. In fact, the long-standing load would eventually overwhelm the controller leading to a possible failure. To predict whether the load in the controller is short-term or long-term load, we used three different classification algorithms: Support Vector Machine, k-Nearest Neighbors, and Naive Bayes. Our evaluation results demonstrate that Support Vector Machine algorithm is applicable for detecting the type of load with an accuracy of 97.93% in a real-time scenario. Besides, our scheme succeeded to offload the controller by switching between the reactive and proactive mode in response to the prediction module output.

  15. Software defined wireless sensor networks application opportunities for efficient network management: a survey

    CSIR Research Space (South Africa)

    Modieginyane, KM

    2017-03-01

    Full Text Available Wireless Sensor Networks (WSNs) are commonly used information technologies of modern networking and computing platforms. Today's network computing applications are faced with a high demand of powerful network functionalities. Functional network...

  16. Modeling of a 3DTV service in the software-defined networking architecture

    Science.gov (United States)

    Wilczewski, Grzegorz

    2014-11-01

    In this article a newly developed concept towards modeling of a multimedia service offering stereoscopic motion imagery is presented. Proposed model is based on the approach of utilization of Software-defined Networking or Software Defined Networks architecture (SDN). The definition of 3D television service spanning SDN concept is identified, exposing basic characteristic of a 3DTV service in a modern networking organization layout. Furthermore, exemplary functionalities of the proposed 3DTV model are depicted. It is indicated that modeling of a 3DTV service in the Software-defined Networking architecture leads to multiplicity of improvements, especially towards flexibility of a service supporting heterogeneity of end user devices.

  17. Software defined networking firewall for industry 4.0 manufacturing systems

    Directory of Open Access Journals (Sweden)

    Akihiro Tsuchiya

    2018-04-01

    Full Text Available Purpose: In order to leverage automation control data, Industry 4.0 manufacturing systems require industrial devices to be connected to the network. Potentially, this can increase the risk of cyberattacks, which can compromise connected industrial devices to acquire production data or gain control over the production process. Search engines such as Sentient Hyper-Optimized Data Access Network (SHODAN can be perverted by attackers to acquire network information that can be later used for intrusion. To prevent this, cybersecurity standards propose network architectures divided into several networks segments based on system functionalities. In this architecture, Firewalls limit the exposure of industrial control devices in order to minimize security risks. This paper presents a novel Software Defined Networking (SDN Firewall that automatically applies this standard architecture without compromising network flexibility.   Design/methodology/approach: The proposed SDN Firewall changes filtering rules in order to implement the different network segments according to application level access control policies. The Firewall applies two filtering techniques described in this paper: temporal filtering and spatial filtering, so that only applications in a white list can connect to industrial control devices. Network administrators need only to configure this application-oriented white lists to comply with security standards for ICS. This simplifies to a great extent network management tasks. Authors have developed a prototype implementation based on the OPC UA Standard and conducted security tests in order to test the viability of the proposal. Findings: Network segmentation and segregation are effective counter-measures against network scanning attacks. The proposed SDN Firewall effectively configures a flat network into virtual LAN segments according to security standard guidelines. Research limitations/implications: The prototype implementation still

  18. Linear Programming Approaches for Power Savings in Software-defined Networks

    NARCIS (Netherlands)

    Moghaddam, F.A.; Grosso, P.

    2016-01-01

    Software-defined networks have been proposed as a viable solution to decrease the power consumption of the networking component in data center networks. Still the question remains on which scheduling algorithms are most suited to achieve this goal. We propose 4 different linear programming

  19. Cloud-Centric and Logically Isolated Virtual Network Environment Based on Software-Defined Wide Area Network

    Directory of Open Access Journals (Sweden)

    Dongkyun Kim

    2017-12-01

    Full Text Available Recent development of distributed cloud environments requires advanced network infrastructure in order to facilitate network automation, virtualization, high performance data transfer, and secured access of end-to-end resources across regional boundaries. In order to meet these innovative cloud networking requirements, software-defined wide area network (SD-WAN is primarily demanded to converge distributed cloud resources (e.g., virtual machines (VMs in a programmable and intelligent manner over distant networks. Therefore, this paper proposes a logically isolated networking scheme designed to integrate distributed cloud resources to dynamic and on-demand virtual networking over SD-WAN. The performance evaluation and experimental results of the proposed scheme indicate that virtual network convergence time is minimized in two different network models such as: (1 an operating OpenFlow-oriented SD-WAN infrastructure (KREONET-S which is deployed on the advanced national research network in Korea, and (2 Mininet-based experimental and emulated networks.

  20. Characterizations of the Beta and the Degree Network Power Measure

    NARCIS (Netherlands)

    van den Brink, J.R.; Borm, P.; Hendrickx, R.; Owen, G.

    2008-01-01

    A symmetric network consists of a set of positions and a set of bilateral links between these positions. For every symmetric network we define a cooperative transferable utility game that measures the "power" of each coalition of positions in the network. Applying the Shapley value to this game

  1. Multiple Social Networks, Data Models and Measures for

    DEFF Research Database (Denmark)

    Magnani, Matteo; Rossi, Luca

    2017-01-01

    Multiple Social Network Analysis is a discipline defining models, measures, methodologies, and algorithms to study multiple social networks together as a single social system. It is particularly valuable when the networks are interconnected, e.g., the same actors are present in more than one...

  2. How to define a word in a lexical network?

    Directory of Open Access Journals (Sweden)

    Dorota Sikora

    2012-01-01

    Full Text Available As underlined in Wierzbicka (1996: 239, a «linguistic definition is a scientific hypothesis about the concept encoded in a given word». The present paper focuses on the problem of what such hypothesis is about. Lexicon of any language is structured with a set of connections relating lexical items. That is to say that speakers of any language need to master not only separate words, but rather a cluster of connected senses. If so, then a lexical definition should lay out the concept the word lexicalizes in the way that gives access to the whole grasp of its conceptual, paradigmatic and syntagmatic relations. We discuss the topic of definitional structures developed in the context of the French Lexical Network (Réseau Lexical du Français.

  3. A taxonomy for software-defined networking, man-in-the-middle attacks

    OpenAIRE

    Fischer, Briana D.; Lato, Anita M.

    2016-01-01

    Approved for public release; distribution is unlimited In contrast to traditional networks, Software Defined Networking (SDN) allows the programming of network functions via an Application Programming Interface (API). The ability to implement the APIs in software is advantageous for traffic manipulation in SDN. With automated logic being programmed into a centralized component of the SDN, network operators are presented with new and scalable methods for traffic manipulation. Enterprises an...

  4. Measure of robustness for complex networks

    Science.gov (United States)

    Youssef, Mina Nabil

    Critical infrastructures are repeatedly attacked by external triggers causing tremendous amount of damages. Any infrastructure can be studied using the powerful theory of complex networks. A complex network is composed of extremely large number of different elements that exchange commodities providing significant services. The main functions of complex networks can be damaged by different types of attacks and failures that degrade the network performance. These attacks and failures are considered as disturbing dynamics, such as the spread of viruses in computer networks, the spread of epidemics in social networks, and the cascading failures in power grids. Depending on the network structure and the attack strength, every network differently suffers damages and performance degradation. Hence, quantifying the robustness of complex networks becomes an essential task. In this dissertation, new metrics are introduced to measure the robustness of technological and social networks with respect to the spread of epidemics, and the robustness of power grids with respect to cascading failures. First, we introduce a new metric called the Viral Conductance (VCSIS ) to assess the robustness of networks with respect to the spread of epidemics that are modeled through the susceptible/infected/susceptible (SIS) epidemic approach. In contrast to assessing the robustness of networks based on a classical metric, the epidemic threshold, the new metric integrates the fraction of infected nodes at steady state for all possible effective infection strengths. Through examples, VCSIS provides more insights about the robustness of networks than the epidemic threshold. In addition, both the paradoxical robustness of Barabasi-Albert preferential attachment networks and the effect of the topology on the steady state infection are studied, to show the importance of quantifying the robustness of networks. Second, a new metric VCSIR is introduced to assess the robustness of networks with respect

  5. Reference Architecture for Multi-Layer Software Defined Optical Data Center Networks

    Directory of Open Access Journals (Sweden)

    Casimer DeCusatis

    2015-09-01

    Full Text Available As cloud computing data centers grow larger and networking devices proliferate; many complex issues arise in the network management architecture. We propose a framework for multi-layer; multi-vendor optical network management using open standards-based software defined networking (SDN. Experimental results are demonstrated in a test bed consisting of three data centers interconnected by a 125 km metropolitan area network; running OpenStack with KVM and VMW are components. Use cases include inter-data center connectivity via a packet-optical metropolitan area network; intra-data center connectivity using an optical mesh network; and SDN coordination of networking equipment within and between multiple data centers. We create and demonstrate original software to implement virtual network slicing and affinity policy-as-a-service offerings. Enhancements to synchronous storage backup; cloud exchanges; and Fibre Channel over Ethernet topologies are also discussed.

  6. A Service-Oriented Approach for Dynamic Chaining of Virtual Network Functions over Multi-Provider Software-Defined Networks

    Directory of Open Access Journals (Sweden)

    Barbara Martini

    2016-06-01

    Full Text Available Emerging technologies such as Software-Defined Networks (SDN and Network Function Virtualization (NFV promise to address cost reduction and flexibility in network operation while enabling innovative network service delivery models. However, operational network service delivery solutions still need to be developed that actually exploit these technologies, especially at the multi-provider level. Indeed, the implementation of network functions as software running over a virtualized infrastructure and provisioned on a service basis let one envisage an ecosystem of network services that are dynamically and flexibly assembled by orchestrating Virtual Network Functions even across different provider domains, thereby coping with changeable user and service requirements and context conditions. In this paper we propose an approach that adopts Service-Oriented Architecture (SOA technology-agnostic architectural guidelines in the design of a solution for orchestrating and dynamically chaining Virtual Network Functions. We discuss how SOA, NFV, and SDN may complement each other in realizing dynamic network function chaining through service composition specification, service selection, service delivery, and placement tasks. Then, we describe the architecture of a SOA-inspired NFV orchestrator, which leverages SDN-based network control capabilities to address an effective delivery of elastic chains of Virtual Network Functions. Preliminary results of prototype implementation and testing activities are also presented. The benefits for Network Service Providers are also described that derive from the adaptive network service provisioning in a multi-provider environment through the orchestration of computing and networking services to provide end users with an enhanced service experience.

  7. State of the Art and Recent Research Advances in Software Defined Networking

    Directory of Open Access Journals (Sweden)

    Taimur Bakhshi

    2017-01-01

    Full Text Available Emerging network services and subsequent growth in the networking infrastructure have gained tremendous momentum in recent years. Application performance requiring rapid real-time network provisioning, optimized traffic management, and virtualization of shared resources has induced the conceptualization and adoption of new networking models. Software defined networking (SDN, one of the predominant and relatively new networking paradigms, seeks to simplify network management by decoupling network control logic from the underlying hardware and introduces real-time network programmability enabling innovation. The present work reviews the state of the art in software defined networking providing a historical perspective on complementary technologies in network programmability and the inherent shortcomings which paved the way for SDN. The SDN architecture is discussed along with popular protocols, platforms, and existing simulation and debugging solutions. Furthermore, a detailed analysis is presented around recent SDN development and deployment avenues ranging from mobile communications and data centers to campus networks and residential environments. The review concludes by highlighting implementation challenges and subsequent research directions being pursued in academia and industry to address issues related to application performance, control plane scalability and design, security, and interdomain connectivity in the context of SDN.

  8. Capacity Extension of Software Defined Data Center Networks With Jellyfish Topology

    DEFF Research Database (Denmark)

    Mehmeri, Victor; Vegas Olmos, Juan José; Tafur Monroy, Idelfonso

    We present a performance analysis of Jellyfish topology with Software-Defined commodity switches for Data Center networks. Our results show up to a 2-fold performance gain when compared to a Spanning Tree Protocol implementation.......We present a performance analysis of Jellyfish topology with Software-Defined commodity switches for Data Center networks. Our results show up to a 2-fold performance gain when compared to a Spanning Tree Protocol implementation....

  9. Feature-based comparison and selection of software defined networking (SDN) controllers

    OpenAIRE

    Khondoker, Rahamatullah; Zaalouk, Adel; Marx, Ronald; Bayarou, Kpatcha

    2014-01-01

    Software Defined Networking (SDN) is seen as one way to solve some problems of the Internet including security, managing complexity, multi-casting, load balancing, and energy efficiency. SDN is an architectural paradigm that separates the control plane of a networking device (e.g., a switch / router) from its data plane, making it feasible to control, monitor, and manage a network from a centralized node (the SDN controller). However, today there exists many SDN controllers including POX, Flo...

  10. Improving Distributed Denial of Service (DDOS Detection using Entropy Method in Software Defined Network (SDN

    Directory of Open Access Journals (Sweden)

    Maman Abdurohman

    2017-12-01

    Full Text Available This research proposed a new method to enhance Distributed Denial of Service (DDoS detection attack on Software Defined Network (SDN environment. This research utilized the OpenFlow controller of SDN for DDoS attack detection using modified method and regarding entropy value. The new method would check whether the traffic was a normal traffic or DDoS attack by measuring the randomness of the packets. This method consisted of two steps, detecting attack and checking the entropy. The result shows that the new method can reduce false positive when there is a temporary and sudden increase in normal traffic. The new method succeeds in not detecting this as a DDoS attack. Compared to previous methods, this proposed method can enhance DDoS attack detection on SDN environment.

  11. Experimental demonstration of software defined data center optical networks with Tbps end-to-end tunability

    Science.gov (United States)

    Zhao, Yongli; Zhang, Jie; Ji, Yuefeng; Li, Hui; Wang, Huitao; Ge, Chao

    2015-10-01

    The end-to-end tunability is important to provision elastic channel for the burst traffic of data center optical networks. Then, how to complete the end-to-end tunability based on elastic optical networks? Software defined networking (SDN) based end-to-end tunability solution is proposed for software defined data center optical networks, and the protocol extension and implementation procedure are designed accordingly. For the first time, the flexible grid all optical networks with Tbps end-to-end tunable transport and switch system have been online demonstrated for data center interconnection, which are controlled by OpenDayLight (ODL) based controller. The performance of the end-to-end tunable transport and switch system has been evaluated with wavelength number tuning, bit rate tuning, and transmit power tuning procedure.

  12. Software-defined networking control plane for seamless integration of multiple silicon photonic switches in Datacom networks.

    Science.gov (United States)

    Shen, Yiwen; Hattink, Maarten H N; Samadi, Payman; Cheng, Qixiang; Hu, Ziyiz; Gazman, Alexander; Bergman, Keren

    2018-04-16

    Silicon photonics based switches offer an effective option for the delivery of dynamic bandwidth for future large-scale Datacom systems while maintaining scalable energy efficiency. The integration of a silicon photonics-based optical switching fabric within electronic Datacom architectures requires novel network topologies and arbitration strategies to effectively manage the active elements in the network. We present a scalable software-defined networking control plane to integrate silicon photonic based switches with conventional Ethernet or InfiniBand networks. Our software-defined control plane manages both electronic packet switches and multiple silicon photonic switches for simultaneous packet and circuit switching. We built an experimental Dragonfly network testbed with 16 electronic packet switches and 2 silicon photonic switches to evaluate our control plane. Observed latencies occupied by each step of the switching procedure demonstrate a total of 344 µs control plane latency for data-center and high performance computing platforms.

  13. Design of a stateless low-latency router architecture for green software-defined networking

    DEFF Research Database (Denmark)

    Saldaña Cercos, Silvia; Ramos, Ramon M.; Eller, Ana C. Ewald

    2015-01-01

    Expanding software defined networking (SDN) to transport networks requires new strategies to deal with the large number of flows that future core networks will have to face. New south-bound protocols within SDN have been proposed to benefit from having control plane detached from the data plane...... offering a cost- and energy-efficient forwarding engine. This paper presents an overview of a new approach named KeyFlow to simultaneously reduce latency, jitter, and power consumption in core network nodes. Results on an emulation platform indicate that round trip time (RTT) can be reduced above 50...

  14. The Evolution of Gene Regulatory Networks that Define Arthropod Body Plans.

    Science.gov (United States)

    Auman, Tzach; Chipman, Ariel D

    2017-09-01

    Our understanding of the genetics of arthropod body plan development originally stems from work on Drosophila melanogaster from the late 1970s and onward. In Drosophila, there is a relatively detailed model for the network of gene interactions that proceeds in a sequential-hierarchical fashion to define the main features of the body plan. Over the years, we have a growing understanding of the networks involved in defining the body plan in an increasing number of arthropod species. It is now becoming possible to tease out the conserved aspects of these networks and to try to reconstruct their evolution. In this contribution, we focus on several key nodes of these networks, starting from early patterning in which the main axes are determined and the broad morphological domains of the embryo are defined, and on to later stage wherein the growth zone network is active in sequential addition of posterior segments. The pattern of conservation of networks is very patchy, with some key aspects being highly conserved in all arthropods and others being very labile. Many aspects of early axis patterning are highly conserved, as are some aspects of sequential segment generation. In contrast, regional patterning varies among different taxa, and some networks, such as the terminal patterning network, are only found in a limited range of taxa. The growth zone segmentation network is ancient and is probably plesiomorphic to all arthropods. In some insects, it has undergone significant modification to give rise to a more hardwired network that generates individual segments separately. In other insects and in most arthropods, the sequential segmentation network has undergone a significant amount of systems drift, wherein many of the genes have changed. However, it maintains a conserved underlying logic and function. © The Author 2017. Published by Oxford University Press on behalf of the Society for Integrative and Comparative Biology. All rights reserved. For permissions please

  15. End-to-end Information Flow Security Model for Software-Defined Networks

    Directory of Open Access Journals (Sweden)

    D. Ju. Chaly

    2015-01-01

    Full Text Available Software-defined networks (SDN are a novel paradigm of networking which became an enabler technology for many modern applications such as network virtualization, policy-based access control and many others. Software can provide flexibility and fast-paced innovations in the networking; however, it has a complex nature. In this connection there is an increasing necessity of means for assuring its correctness and security. Abstract models for SDN can tackle these challenges. This paper addresses to confidentiality and some integrity properties of SDNs. These are critical properties for multi-tenant SDN environments, since the network management software must ensure that no confidential data of one tenant are leaked to other tenants in spite of using the same physical infrastructure. We define a notion of end-to-end security in context of software-defined networks and propose a semantic model where the reasoning is possible about confidentiality, and we can check that confidential information flows do not interfere with non-confidential ones. We show that the model can be extended in order to reason about networks with secure and insecure links which can arise, for example, in wireless environments.The article is published in the authors’ wording.

  16. Controller Placement Algorithms in Software Defined Network - A Review of Trends and Challenges

    Directory of Open Access Journals (Sweden)

    Yoon Si-Kee

    2017-01-01

    Full Text Available Traditional network architectures are complex to manage, comparatively static, rigid and difficult to make changes for new innovation. The proprietary devices in such architectures are based on manual configuration which are unwieldy and error-prone. Software Defined Network (SDN which is described as a new network paradigm that decouple the control plane from data plane are capable to solve today's network issues and improve the network performance. Nevertheless, among so many challenges and research opportunity in SDN, Controller Placement Problem (CPP is said to be the most important issues which can directly affect the overall network performance. Thus far, the issue regarding the CPP and its challenge has not been completely reviewed and discussed properly in any other papers. In this paper, we provide a comprehensive review on several optimized controller placement problem algorithms in SDN. This paper also highlights some limitations of the reviewed methods and also emphasizes on suitable approach to address the aforementioned problems.

  17. TopoGen: A Network Topology Generation Architecture with application to automating simulations of Software Defined Networks

    CERN Document Server

    Laurito, Andres; The ATLAS collaboration

    2017-01-01

    Simulation is an important tool to validate the performance impact of control decisions in Software Defined Networks (SDN). Yet, the manual modeling of complex topologies that may change often during a design process can be a tedious error-prone task. We present TopoGen, a general purpose architecture and tool for systematic translation and generation of network topologies. TopoGen can be used to generate network simulation models automatically by querying information available at diverse sources, notably SDN controllers. The DEVS modeling and simulation framework facilitates a systematic translation of structured knowledge about a network topology into a formal modular and hierarchical coupling of preexisting or new models of network entities (physical or logical). TopoGen can be flexibly extended with new parsers and generators to grow its scope of applicability. This permits to design arbitrary workflows of topology transformations. We tested TopoGen in a network engineering project for the ATLAS detector ...

  18. TopoGen: A Network Topology Generation Architecture with application to automating simulations of Software Defined Networks

    CERN Document Server

    Laurito, Andres; The ATLAS collaboration

    2018-01-01

    Simulation is an important tool to validate the performance impact of control decisions in Software Defined Networks (SDN). Yet, the manual modeling of complex topologies that may change often during a design process can be a tedious error-prone task. We present TopoGen, a general purpose architecture and tool for systematic translation and generation of network topologies. TopoGen can be used to generate network simulation models automatically by querying information available at diverse sources, notably SDN controllers. The DEVS modeling and simulation framework facilitates a systematic translation of structured knowledge about a network topology into a formal modular and hierarchical coupling of preexisting or new models of network entities (physical or logical). TopoGen can be flexibly extended with new parsers and generators to grow its scope of applicability. This permits to design arbitrary workflows of topology transformations. We tested TopoGen in a network engineering project for the ATLAS detector ...

  19. Hyperbolicity measures democracy in real-world networks

    Science.gov (United States)

    Borassi, Michele; Chessa, Alessandro; Caldarelli, Guido

    2015-09-01

    In this work, we analyze the hyperbolicity of real-world networks, a geometric quantity that measures if a space is negatively curved. We provide two improvements in our understanding of this quantity: first of all, in our interpretation, a hyperbolic network is "aristocratic", since few elements "connect" the system, while a non-hyperbolic network has a more "democratic" structure with a larger number of crucial elements. The second contribution is the introduction of the average hyperbolicity of the neighbors of a given node. Through this definition, we outline an "influence area" for the vertices in the graph. We show that in real networks the influence area of the highest degree vertex is small in what we define "local" networks (i.e., social or peer-to-peer networks), and large in "global" networks (i.e., power grid, metabolic networks, or autonomous system networks).

  20. Defining, Developing, and Measuring "Proclivities for Teaching Mathematics"

    Science.gov (United States)

    Lewis, Jennifer M.; Fischman, Davida; Riggs, Matt

    2015-01-01

    This article presents a form of teacher reasoning that we call "proclivities for teaching mathematics." We define proclivities for teaching mathematics as the beliefs, knowledge, and dispositions that are actionable in the flow of instruction, and we argue that growth in this area contributes to positive change in mathematics…

  1. Software-defined optical network for metro-scale geographically distributed data centers.

    Science.gov (United States)

    Samadi, Payman; Wen, Ke; Xu, Junjie; Bergman, Keren

    2016-05-30

    The emergence of cloud computing and big data has rapidly increased the deployment of small and mid-sized data centers. Enterprises and cloud providers require an agile network among these data centers to empower application reliability and flexible scalability. We present a software-defined inter data center network to enable on-demand scale out of data centers on a metro-scale optical network. The architecture consists of a combined space/wavelength switching platform and a Software-Defined Networking (SDN) control plane equipped with a wavelength and routing assignment module. It enables establishing transparent and bandwidth-selective connections from L2/L3 switches, on-demand. The architecture is evaluated in a testbed consisting of 3 data centers, 5-25 km apart. We successfully demonstrated end-to-end bulk data transfer and Virtual Machine (VM) migrations across data centers with less than 100 ms connection setup time and close to full link capacity utilization.

  2. Performance Analysis of Congestion Control Mechanism in Software Defined Network (SDN

    Directory of Open Access Journals (Sweden)

    Rahman M. Z. A.

    2017-01-01

    Full Text Available In the near future, the traditional networks architecture will be difficult to be managed. Hence, Software Defined Network (SDN will be an alternative in the future of programmable networks to replace the conventional network architecture. The main idea of SDN architecture is to separate the forwarding plane and control plane of network system, where network operators can program packet forwarding behaviour to improve the network performance. Congestion control is important mechanism for network traffic to improve network capability and achieve high end Quality of Service (QoS. In this paper, extensive simulation is conducted to analyse the performance of SDN by implementing Link Layer Discovery Protocol (LLDP under congested network. The simulation was conducted on Mininet by creating four different fanout and the result was analysed based on differences of matrix performance. As a result, the packet loss and throughput reduction were observed when number of fanout in the topology was increased. By using LLDP protocol, huge reduction in packet loss rate has been achieved while maximizing percentage packet delivery ratio.

  3. Software Defined Networking to support IP address mobility in future LTE network

    NARCIS (Netherlands)

    Karimzadeh Motallebi Azar, Morteza; Valtulina, Luca; van den Berg, Hans Leo; Pras, Aiko; Liebsch, Marco; Taleb, Tarik

    2017-01-01

    The existing LTE network architecture dose not scale well to increasing demands due to its highly centralized and hierarchical composition. In this paper we discuss the major modifications required in the current LTE network to realize a decentralized LTE architecture. Next, we develop two IP

  4. Optimisation of Software-Defined Networks Performance Using a Hybrid Intelligent System

    Directory of Open Access Journals (Sweden)

    Ann Sabih

    2017-06-01

    Full Text Available This paper proposes a novel intelligent technique that has been designed to optimise the performance of Software Defined Networks (SDN. The proposed hybrid intelligent system has employed integration of intelligence-based optimisation approaches with the artificial neural network. These heuristic optimisation methods include Genetic Algorithms (GA and Particle Swarm Optimisation (PSO. These methods were utilised separately in order to select the best inputs to maximise SDN performance. In order to identify SDN behaviour, the neural network model is trained and applied. The maximal optimisation approach has been identified using an analytical approach that considered SDN performance and the computational time as objective functions. Initially, the general model of the neural network was tested with unseen data before implementing the model using GA and PSO to determine the optimal performance of SDN. The results showed that the SDN represented by Artificial Neural Network ANN, and optmised by PSO, generated a better configuration with regards to computational efficiency and performance index.

  5. Analyzing complex networks through correlations in centrality measurements

    International Nuclear Information System (INIS)

    Ricardo Furlan Ronqui, José; Travieso, Gonzalo

    2015-01-01

    Many real world systems can be expressed as complex networks of interconnected nodes. It is frequently important to be able to quantify the relative importance of the various nodes in the network, a task accomplished by defining some centrality measures, with different centrality definitions stressing different aspects of the network. It is interesting to know to what extent these different centrality definitions are related for different networks. In this work, we study the correlation between pairs of a set of centrality measures for different real world networks and two network models. We show that the centralities are in general correlated, but with stronger correlations for network models than for real networks. We also show that the strength of the correlation of each pair of centralities varies from network to network. Taking this fact into account, we propose the use of a centrality correlation profile, consisting of the values of the correlation coefficients between all pairs of centralities of interest, as a way to characterize networks. Using the yeast protein interaction network as an example we show also that the centrality correlation profile can be used to assess the adequacy of a network model as a representation of a given real network. (paper)

  6. Dynamic Flow Migration for Delay Constrained Traffic in Software-Defined Networks

    NARCIS (Netherlands)

    Berger, Andre; Gross, James; Danielis, Peter; Dán, György

    2017-01-01

    Various industrial control applications have stringent end-to-end latency requirements in the order of a few milliseconds. Software-defined networking (SDN) is a promising solution in order to meet these stringent requirements under varying traffic patterns, as it enables the flexible management of

  7. Contribution of past and future self-defining event networks to personal identity.

    Science.gov (United States)

    Demblon, Julie; D'Argembeau, Arnaud

    2017-05-01

    Personal identity is nourished by memories of significant past experiences and by the imagination of meaningful events that one anticipates to happen in the future. The organisation of such self-defining memories and prospective thoughts in the cognitive system has received little empirical attention, however. In the present study, our aims were to investigate to what extent self-defining memories and future projections are organised in networks of related events, and to determine the nature of the connections linking these events. Our results reveal the existence of self-defining event networks, composed of both memories and future events of similar centrality for identity and characterised by similar identity motives. These self-defining networks expressed a strong internal coherence and frequently organised events in meaningful themes and sequences (i.e., event clusters). Finally, we found that the satisfaction of identity motives in represented events and the presence of clustering across events both contributed to increase in the perceived centrality of events for the sense of identity. Overall, these findings suggest that personal identity is not only nourished by representations of significant past and future events, but also depends on the formation of coherent networks of related events that provide an overarching meaning to specific life experiences.

  8. Energy-Saving Traffic Scheduling in Hybrid Software Defined Wireless Rechargeable Sensor Networks.

    Science.gov (United States)

    Wei, Yunkai; Ma, Xiaohui; Yang, Ning; Chen, Yijin

    2017-09-15

    Software Defined Wireless Rechargeable Sensor Networks (SDWRSNs) are an inexorable trend for Wireless Sensor Networks (WSNs), including Wireless Rechargeable Sensor Network (WRSNs). However, the traditional network devices cannot be completely substituted in the short term. Hybrid SDWRSNs, where software defined devices and traditional devices coexist, will last for a long time. Hybrid SDWRSNs bring new challenges as well as opportunities for energy saving issues, which is still a key problem considering that the wireless chargers are also exhaustible, especially in some rigid environment out of the main supply. Numerous energy saving schemes for WSNs, or even some works for WRSNs, are no longer suitable for the new features of hybrid SDWRSNs. To solve this problem, this paper puts forward an Energy-saving Traffic Scheduling (ETS) algorithm. The ETS algorithm adequately considers the new characters in hybrid SDWRSNs, and takes advantage of the Software Defined Networking (SDN) controller's direct control ability on SDN nodes and indirect control ability on normal nodes. The simulation results show that, comparing with traditional Minimum Transmission Energy (MTE) protocol, ETS can substantially improve the energy efficiency in hybrid SDWRSNs for up to 20-40% while ensuring feasible data delay.

  9. Energy-Saving Traffic Scheduling in Hybrid Software Defined Wireless Rechargeable Sensor Networks

    Directory of Open Access Journals (Sweden)

    Yunkai Wei

    2017-09-01

    Full Text Available Software Defined Wireless Rechargeable Sensor Networks (SDWRSNs are an inexorable trend for Wireless Sensor Networks (WSNs, including Wireless Rechargeable Sensor Network (WRSNs. However, the traditional network devices cannot be completely substituted in the short term. Hybrid SDWRSNs, where software defined devices and traditional devices coexist, will last for a long time. Hybrid SDWRSNs bring new challenges as well as opportunities for energy saving issues, which is still a key problem considering that the wireless chargers are also exhaustible, especially in some rigid environment out of the main supply. Numerous energy saving schemes for WSNs, or even some works for WRSNs, are no longer suitable for the new features of hybrid SDWRSNs. To solve this problem, this paper puts forward an Energy-saving Traffic Scheduling (ETS algorithm. The ETS algorithm adequately considers the new characters in hybrid SDWRSNs, and takes advantage of the Software Defined Networking (SDN controller’s direct control ability on SDN nodes and indirect control ability on normal nodes. The simulation results show that, comparing with traditional Minimum Transmission Energy (MTE protocol, ETS can substantially improve the energy efficiency in hybrid SDWRSNs for up to 20–40% while ensuring feasible data delay.

  10. Resiliency as a component importance measure in network reliability

    International Nuclear Information System (INIS)

    Whitson, John C.; Ramirez-Marquez, Jose Emmanuel

    2009-01-01

    This paper seeks to define the concept of resiliency as a component importance measure related to network reliability. Resiliency can be defined as a composite of: (1) the ability of a network to provide service despite external failures and (2) the time to restore service when in the presence of such failures. Although, Resiliency has been extensively studied in different research areas, this paper will study the specific aspects of quantifiable network resiliency when the network is experiencing potential catastrophic failures from external events and/or influences, and when it is not known a priori which specific components within the network will fail. A formal definition for Category I resiliency is proposed and a step-by-step approach based on Monte-Carlo simulation to calculate it is defined. To illustrate the approach, two-terminal networks with varying degrees of redundancy, have been considered. The results obtained for test networks show that this new quantifiable concept of resiliency provides insight into the performance and topology of the network. Future use for this work could include methods for safeguarding critical network components and optimizing the use of redundancy as a technique to improve network resiliency.

  11. Defining and Measuring Job Vacancies in a Dynamic Perspective

    NARCIS (Netherlands)

    P.A. Donker van Heel (Peter)

    2015-01-01

    textabstractWhat is the best definition for job vacancies, what is the best method to measure job vacancies, and what further research is needed to gain a better insight into job vacancies in a dynamic perspective?

  12. A complex network-based importance measure for mechatronics systems

    Science.gov (United States)

    Wang, Yanhui; Bi, Lifeng; Lin, Shuai; Li, Man; Shi, Hao

    2017-01-01

    In view of the negative impact of functional dependency, this paper attempts to provide an alternative importance measure called Improved-PageRank (IPR) for measuring the importance of components in mechatronics systems. IPR is a meaningful extension of the centrality measures in complex network, which considers usage reliability of components and functional dependency between components to increase importance measures usefulness. Our work makes two important contributions. First, this paper integrates the literature of mechatronic architecture and complex networks theory to define component network. Second, based on the notion of component network, a meaningful IPR is brought into the identifying of important components. In addition, the IPR component importance measures, and an algorithm to perform stochastic ordering of components due to the time-varying nature of usage reliability of components and functional dependency between components, are illustrated with a component network of bogie system that consists of 27 components.

  13. Reliable and Fault-Tolerant Software-Defined Network Operations Scheme for Remote 3D Printing

    Science.gov (United States)

    Kim, Dongkyun; Gil, Joon-Min

    2015-03-01

    The recent wide expansion of applicable three-dimensional (3D) printing and software-defined networking (SDN) technologies has led to a great deal of attention being focused on efficient remote control of manufacturing processes. SDN is a renowned paradigm for network softwarization, which has helped facilitate remote manufacturing in association with high network performance, since SDN is designed to control network paths and traffic flows, guaranteeing improved quality of services by obtaining network requests from end-applications on demand through the separated SDN controller or control plane. However, current SDN approaches are generally focused on the controls and automation of the networks, which indicates that there is a lack of management plane development designed for a reliable and fault-tolerant SDN environment. Therefore, in addition to the inherent advantage of SDN, this paper proposes a new software-defined network operations center (SD-NOC) architecture to strengthen the reliability and fault-tolerance of SDN in terms of network operations and management in particular. The cooperation and orchestration between SDN and SD-NOC are also introduced for the SDN failover processes based on four principal SDN breakdown scenarios derived from the failures of the controller, SDN nodes, and connected links. The abovementioned SDN troubles significantly reduce the network reachability to remote devices (e.g., 3D printers, super high-definition cameras, etc.) and the reliability of relevant control processes. Our performance consideration and analysis results show that the proposed scheme can shrink operations and management overheads of SDN, which leads to the enhancement of responsiveness and reliability of SDN for remote 3D printing and control processes.

  14. Evaluating measurement of dynamic constructs: defining a measurement model of derivatives.

    Science.gov (United States)

    Estabrook, Ryne

    2015-03-01

    While measurement evaluation has been embraced as an important step in psychological research, evaluating measurement structures with longitudinal data is fraught with limitations. This article defines and tests a measurement model of derivatives (MMOD), which is designed to assess the measurement structure of latent constructs both for analyses of between-person differences and for the analysis of change. Simulation results indicate that MMOD outperforms existing models for multivariate analysis and provides equivalent fit to data generation models. Additional simulations show MMOD capable of detecting differences in between-person and within-person factor structures. Model features, applications, and future directions are discussed. (c) 2015 APA, all rights reserved).

  15. Defining the research agenda to measure and reduce tuberculosis stigmas.

    Science.gov (United States)

    Macintyre, K; Bakker, M I; Bergson, S; Bhavaraju, R; Bond, V; Chikovore, J; Colvin, C; Craig, G M; Cremers, A L; Daftary, A; Engel, N; France, N Ferris; Jaramillo, E; Kimerling, M; Kipp, A; Krishnaratne, S; Mergenthaler, C; Ngicho, M; Redwood, L; Rood, E J J; Sommerland, N; Stangl, A; van Rie, A; van Brakel, W; Wouters, E; Zwerling, A; Mitchell, E M H

    2017-11-01

    Crucial to finding and treating the 4 million tuberculosis (TB) patients currently missed by national TB programmes, TB stigma is receiving well-deserved and long-delayed attention at the global level. However, the ability to measure and evaluate the success of TB stigma-reduction efforts is limited by the need for additional tools. At a 2016 TB stigma-measurement meeting held in The Hague, The Netherlands, stigma experts discussed and proposed a research agenda around four themes: 1) drivers: what are the main drivers and domains of TB stigma(s)?; 2) consequences: how consequential are TB stigmas and how are negative impacts most felt?; 3) burden: what is the global prevalence and distribution of TB stigma(s) and what explains any variation? 4): intervention: what can be done to reduce the extent and impact of TB stigma(s)? Each theme was further subdivided into research topics to be addressed to move the agenda forward. These include greater clarity on what causes TB stigmas to emerge and thrive, the difficulty of measuring the complexity of stigma, and the improbability of a universal stigma 'cure'. Nevertheless, these challenges should not hinder investments in the measurement and reduction of TB stigma. We believe it is time to focus on how, and not whether, the global community should measure and reduce TB stigma.

  16. The Challenges of Defining and Measuring Student Engagement in Science

    Science.gov (United States)

    Sinatra, Gale M.; Heddy, Benjamin C.; Lombardi, Doug

    2015-01-01

    Engagement is one of the hottest research topics in the field of educational psychology. Research shows that multifarious benefits occur when students are engaged in their own learning, including increased motivation and achievement. However, there is little agreement on a concrete definition and effective measurement of engagement. This special…

  17. Spasticity, an impairment that is poorly defined and poorly measured

    NARCIS (Netherlands)

    Malhotra, S.; Malhotra, S.; Pandyan, A.D.; Day, C.R.; Jones, Valerie M.; Hermens, Hermanus J.

    Objective: To explore, following a literature review, whether there is a consistent definition and a unified assessment framework for the term 'spasticity'. The congruence between the definitions of spasticity and the corresponding methods of measurement were also explored. Data sources: The search

  18. Software defined networking for improved wireless sensor network management: a survey

    CSIR Research Space (South Africa)

    Ndiaye, M

    2017-05-01

    Full Text Available Wireless sensor networks (WSNs) are becoming increasingly popular with the advent of the Internet of things (IoT). Various real-world applications of WSNs such as in smart grids, smart farming and smart health would require a potential deployment...

  19. Design of a stateless low-latency router architecture for green software-defined networking

    Science.gov (United States)

    Saldaña Cercós, Silvia; Ramos, Ramon M.; Ewald Eller, Ana C.; Martinello, Magnos; Ribeiro, Moisés. R. N.; Manolova Fagertun, Anna; Tafur Monroy, Idelfonso

    2015-01-01

    Expanding software defined networking (SDN) to transport networks requires new strategies to deal with the large number of flows that future core networks will have to face. New south-bound protocols within SDN have been proposed to benefit from having control plane detached from the data plane offering a cost- and energy-efficient forwarding engine. This paper presents an overview of a new approach named KeyFlow to simultaneously reduce latency, jitter, and power consumption in core network nodes. Results on an emulation platform indicate that round trip time (RTT) can be reduced above 50% compared to the reference protocol OpenFlow, specially when flow tables are densely populated. Jitter reduction has been demonstrated experimentally on a NetFPGA-based platform, and 57.3% power consumption reduction has been achieved.

  20. Defining the protein interaction network of human malaria parasite Plasmodium falciparum

    KAUST Repository

    Ramaprasad, Abhinay

    2012-02-01

    Malaria, caused by the protozoan parasite Plasmodium falciparum, affects around 225. million people yearly and a huge international effort is directed towards combating this grave threat to world health and economic development. Considerable advances have been made in malaria research triggered by the sequencing of its genome in 2002, followed by several high-throughput studies defining the malaria transcriptome and proteome. A protein-protein interaction (PPI) network seeks to trace the dynamic interactions between proteins, thereby elucidating their local and global functional relationships. Experimentally derived PPI network from high-throughput methods such as yeast two hybrid (Y2H) screens are inherently noisy, but combining these independent datasets by computational methods tends to give a greater accuracy and coverage. This review aims to discuss the computational approaches used till date to construct a malaria protein interaction network and to catalog the functional predictions and biological inferences made from analysis of the PPI network. © 2011 Elsevier Inc.

  1. The measurement of water scarcity: Defining a meaningful indicator.

    Science.gov (United States)

    Damkjaer, Simon; Taylor, Richard

    2017-09-01

    Metrics of water scarcity and stress have evolved over the last three decades from simple threshold indicators to holistic measures characterising human environments and freshwater sustainability. Metrics commonly estimate renewable freshwater resources using mean annual river runoff, which masks hydrological variability, and quantify subjectively socio-economic conditions characterising adaptive capacity. There is a marked absence of research evaluating whether these metrics of water scarcity are meaningful. We argue that measurement of water scarcity (1) be redefined physically in terms of the freshwater storage required to address imbalances in intra- and inter-annual fluxes of freshwater supply and demand; (2) abandons subjective quantifications of human environments and (3) be used to inform participatory decision-making processes that explore a wide range of options for addressing freshwater storage requirements beyond dams that include use of renewable groundwater, soil water and trading in virtual water. Further, we outline a conceptual framework redefining water scarcity in terms of freshwater storage.

  2. Social network analysis of public health programs to measure partnership.

    Science.gov (United States)

    Schoen, Martin W; Moreland-Russell, Sarah; Prewitt, Kim; Carothers, Bobbi J

    2014-12-01

    In order to prevent chronic diseases, community-based programs are encouraged to take an ecological approach to public health promotion and involve many diverse partners. Little is known about measuring partnership in implementing public health strategies. We collected data from 23 Missouri communities in early 2012 that received funding from three separate programs to prevent obesity and/or reduce tobacco use. While all of these funding programs encourage partnership, only the Social Innovation for Missouri (SIM) program included a focus on building community capacity and enhancing collaboration. Social network analysis techniques were used to understand contact and collaboration networks in community organizations. Measurements of average degree, density, degree centralization, and betweenness centralization were calculated for each network. Because of the various sizes of the networks, we conducted comparative analyses with and without adjustment for network size. SIM programs had increased measurements of average degree for partner collaboration and larger networks. When controlling for network size, SIM groups had higher measures of network density and lower measures of degree centralization and betweenness centralization. SIM collaboration networks were more dense and less centralized, indicating increased partnership. The methods described in this paper can be used to compare partnership in community networks of various sizes. Further research is necessary to define causal mechanisms of partnership development and their relationship to public health outcomes. Copyright © 2014 Elsevier Ltd. All rights reserved.

  3. Defining Tsunami Magnitude as Measure of Potential Impact

    Science.gov (United States)

    Titov, V. V.; Tang, L.

    2016-12-01

    The goal of tsunami forecast, as a system for predicting potential impact of a tsunami at coastlines, requires quick estimate of a tsunami magnitude. This goal has been recognized since the beginning of tsunami research. The work of Kajiura, Soloviev, Abe, Murty, and many others discussed several scales for tsunami magnitude based on estimates of tsunami energy. However, difficulties of estimating tsunami energy based on available tsunami measurements at coastal sea-level stations has carried significant uncertainties and has been virtually impossible in real time, before tsunami impacts coastlines. The slow process of tsunami magnitude estimates, including collection of vast amount of available coastal sea-level data from affected coastlines, made it impractical to use any tsunami magnitude scales in tsunami warning operations. Uncertainties of estimates made tsunami magnitudes difficult to use as universal scale for tsunami analysis. Historically, the earthquake magnitude has been used as a proxy of tsunami impact estimates, since real-time seismic data is available of real-time processing and ample amount of seismic data is available for an elaborate post event analysis. This measure of tsunami impact carries significant uncertainties in quantitative tsunami impact estimates, since the relation between the earthquake and generated tsunami energy varies from case to case. In this work, we argue that current tsunami measurement capabilities and real-time modeling tools allow for establishing robust tsunami magnitude that will be useful for tsunami warning as a quick estimate for tsunami impact and for post-event analysis as a universal scale for tsunamis inter-comparison. We present a method for estimating the tsunami magnitude based on tsunami energy and present application of the magnitude analysis for several historical events for inter-comparison with existing methods.

  4. Advance reservation access control using software-defined networking and tokens

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Joaquin; Jung, Eun-Sung; Kettimuthu, Rajkumar; Rao, Nageswara S. V.; Foster, Ian T.; Clark, Russ; Owen, Henry

    2018-02-01

    Advance reservation systems allow users to reserve dedicated bandwidth connection resources from advanced high-speed networks. A common use case for such systems is data transfers in distributed science environments in which a user wants exclusive access to the reservation. However, current advance network reservation methods cannot ensure exclusive access of a network reservation to the specific flow for which the user made the reservation. We present here a novel network architecture that addresses this limitation and ensures that a reservation is used only by the intended flow. We achieve this by leveraging software-defined networking (SDN) and token-based authorization. We use SDN to orchestrate and automate the reservation of networking resources, end-to-end and across multiple administrative domains, and tokens to create a strong binding between the user or application that requested the reservation and the flows provisioned by SDN. We conducted experiments on the ESNet 100G SDN testbed, and demonstrated that our system effectively protects authorized flows from competing traffic in the network. (C) 2017 Elsevier B.V. All rights reserved.

  5. Virtual optical network provisioning with unified service logic processing model for software-defined multidomain optical networks

    Science.gov (United States)

    Zhao, Yongli; Li, Shikun; Song, Yinan; Sun, Ji; Zhang, Jie

    2015-12-01

    Hierarchical control architecture is designed for software-defined multidomain optical networks (SD-MDONs), and a unified service logic processing model (USLPM) is first proposed for various applications. USLPM-based virtual optical network (VON) provisioning process is designed, and two VON mapping algorithms are proposed: random node selection and per controller computation (RNS&PCC) and balanced node selection and hierarchical controller computation (BNS&HCC). Then an SD-MDON testbed is built with OpenFlow extension in order to support optical transport equipment. Finally, VON provisioning service is experimentally demonstrated on the testbed along with performance verification.

  6. First field trial of Virtual Network Operator oriented network on demand (NoD) service provisioning over software defined multi-vendor OTN networks

    Science.gov (United States)

    Li, Yajie; Zhao, Yongli; Zhang, Jie; Yu, Xiaosong; Chen, Haoran; Zhu, Ruijie; Zhou, Quanwei; Yu, Chenbei; Cui, Rui

    2017-01-01

    A Virtual Network Operator (VNO) is a provider and reseller of network services from other telecommunications suppliers. These network providers are categorized as virtual because they do not own the underlying telecommunication infrastructure. In terms of business operation, VNO can provide customers with personalized services by leasing network infrastructure from traditional network providers. The unique business modes of VNO lead to the emergence of network on demand (NoD) services. The conventional network provisioning involves a series of manual operation and configuration, which leads to high cost in time. Considering the advantages of Software Defined Networking (SDN), this paper proposes a novel NoD service provisioning solution to satisfy the private network need of VNOs. The solution is first verified in the real software defined multi-domain optical networks with multi-vendor OTN equipment. With the proposed solution, NoD service can be deployed via online web portals in near-real time. It reinvents the customer experience and redefines how network services are delivered to customers via an online self-service portal. Ultimately, this means a customer will be able to simply go online, click a few buttons and have new services almost instantaneously.

  7. Measurement methods on the complexity of network

    Institute of Scientific and Technical Information of China (English)

    LIN Lin; DING Gang; CHEN Guo-song

    2010-01-01

    Based on the size of network and the number of paths in the network,we proposed a model of topology complexity of a network to measure the topology complexity of the network.Based on the analyses of the effects of the number of the equipment,the types of equipment and the processing time of the node on the complexity of the network with the equipment-constrained,a complexity model of equipment-constrained network was constructed to measure the integrated complexity of the equipment-constrained network.The algorithms for the two models were also developed.An automatic generator of the random single label network was developed to test the models.The results show that the models can correctly evaluate the topology complexity and the integrated complexity of the networks.

  8. Using Software-Defined Networking for Ransomware Mitigation: the Case of CryptoWall

    OpenAIRE

    Cabaj, Krzysztof; Mazurczyk, Wojciech

    2016-01-01

    Currently, different forms of ransomware are increasingly threatening Internet users. Modern ransomware encrypts important user data and it is only possible to recover it once a ransom has been paid. In this paper we show how Software-Defined Networking (SDN) can be utilized to improve ransomware mitigation. In more detail, we analyze the behavior of popular ransomware - CryptoWall - and, based on this knowledge, we propose two real-time mitigation methods. Then we designed the SDN-based syst...

  9. SD-EAR: Energy Aware Routing in Software Defined Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Anuradha Banerjee

    2018-06-01

    Full Text Available In today’s internet-of-things (IoT environment, wireless sensor networks (WSNs have many advantages, with broad applications in different areas including environmental monitoring, maintaining security, etc. However, high energy depletion may lead to node failures in WSNs. In most WSNs, nodes deplete energy mainly because of the flooding and broadcasting of route-request (RREQ packets, which is essential for route discovery in WSNs. The present article models wireless sensor networks as software-defined wireless sensor networks (SD-WSNs where the network is divided into multiple clusters or zones, and each zone is controlled by a software-defined network (SDN controller. The SDN controller is aware of the topology of each zone, and finds out the optimum energy efficient path from any source to any destination inside the zone. For destinations outside of the zone, the SDN controller of the source zone instructs the source to send a message to all of the peripheral nodes in that zone, so that they can forward the message to the peripheral nodes in other zones, and the process goes on until a destination is found. As far as energy-efficient path selection is concerned, the SDN controller of a zone is aware of the connectivity and residual energy of each node. Therefore, it is capable of discovering an optimum energy efficient path from any source to any destination inside as well as outside of the zone of the source. Accordingly, flow tables in different routers are updated dynamically. The task of route discovery is shifted from individual nodes to controllers, and as a result, the flooding of route-requests is completely eliminated. Software-defined energy aware routing (SD-EARalso proposes an innovative sleeping strategy where exhausted nodes are allowed to go to sleep through a sleep request—sleep grant mechanism. All of these result in huge energy savings in SD-WSN, as shown in the simulation results.

  10. Software defined multi-OLT passive optical network for flexible traffic allocation

    Science.gov (United States)

    Zhang, Shizong; Gu, Rentao; Ji, Yuefeng; Zhang, Jiawei; Li, Hui

    2016-10-01

    With the rapid growth of 4G mobile network and vehicular network services mobile terminal users have increasing demand on data sharing among different radio remote units (RRUs) and roadside units (RSUs). Meanwhile, commercial video-streaming, video/voice conference applications delivered through peer-to-peer (P2P) technology are still keep on stimulating the sharp increment of bandwidth demand in both business and residential subscribers. However, a significant issue is that, although wavelength division multiplexing (WDM) and orthogonal frequency division multiplexing (OFDM) technology have been proposed to fulfil the ever-increasing bandwidth demand in access network, the bandwidth of optical fiber is not unlimited due to the restriction of optical component properties and modulation/demodulation technology, and blindly increase the wavelength cannot meet the cost-sensitive characteristic of the access network. In this paper, we propose a software defined multi-OLT PON architecture to support efficient scheduling of access network traffic. By introducing software defined networking technology and wavelength selective switch into TWDM PON system in central office, multiple OLTs can be considered as a bandwidth resource pool and support flexible traffic allocation for optical network units (ONUs). Moreover, under the configuration of the control plane, ONUs have the capability of changing affiliation between different OLTs under different traffic situations, thus the inter-OLT traffic can be localized and the data exchange pressure of the core network can be released. Considering this architecture is designed to be maximum following the TWDM PON specification, the existing optical distribution network (ODN) investment can be saved and conventional EPON/GPON equipment can be compatible with the proposed architecture. What's more, based on this architecture, we propose a dynamic wavelength scheduling algorithm, which can be deployed as an application on control plane

  11. A DDoS Attack Detection Method Based on SVM in Software Defined Network

    Directory of Open Access Journals (Sweden)

    Jin Ye

    2018-01-01

    Full Text Available The detection of DDoS attacks is an important topic in the field of network security. The occurrence of software defined network (SDN (Zhang et al., 2018 brings up some novel methods to this topic in which some deep learning algorithm is adopted to model the attack behavior based on collecting from the SDN controller. However, the existing methods such as neural network algorithm are not practical enough to be applied. In this paper, the SDN environment by mininet and floodlight (Ning et al., 2014 simulation platform is constructed, 6-tuple characteristic values of the switch flow table is extracted, and then DDoS attack model is built by combining the SVM classification algorithms. The experiments show that average accuracy rate of our method is 95.24% with a small amount of flow collecting. Our work is of good value for the detection of DDoS attack in SDN.

  12. Energy-Aware Routing in Multiple Domains Software-Defined Networks

    Directory of Open Access Journals (Sweden)

    Adriana FERNÁNDEZ-FERNÁNDEZ

    2016-12-01

    Full Text Available The growing energy consumption of communication networks has attracted the attention of the networking researchers in the last decade. In this context, the new architecture of Software-Defined Networks (SDN allows a flexible programmability, suitable for the power-consumption optimization problem. In this paper we address the issue of designing a novel distributed routing algorithm that optimizes the power consumption in large scale SDN with multiple domains. The solution proposed, called DEAR (Distributed Energy-Aware Routing, tackles the problem of minimizing the number of links that can be used to satisfy a given data traffic demand under performance constraints such as control traffic delay and link utilization. To this end, we present a complete formulation of the optimization problem that considers routing requirements for control and data plane communications. Simulation results confirm that the proposed solution enables the achievement of significant energy savings.

  13. Unified Multi-Layer among Software Defined Multi-Domain Optical Networks (Invited

    Directory of Open Access Journals (Sweden)

    Hui Yang

    2015-06-01

    Full Text Available The software defined networking (SDN enabled by OpenFlow protocol has gained popularity which can enable the network to be programmable and accommodate both fixed and flexible bandwidth services. In this paper, we present a unified multi-layer (UML architecture with multiple controllers and a dynamic orchestra plane (DOP for software defined multi-domain optical networks. The proposed architecture can shield the differences among various optical devices from multi-vendors and the details of connecting heterogeneous networks. The cross-domain services with on-demand bandwidth can be deployed via unified interfaces provided by the dynamic orchestra plane. Additionally, the globalization strategy and practical capture of signal processing are presented based on the architecture. The overall feasibility and efficiency of the proposed architecture is experimentally verified on the control plane of our OpenFlow-based testbed. The performance of globalization strategy under heavy traffic load scenario is also quantitatively evaluated based on UML architecture compared with other strategies in terms of blocking probability, average hops, and average resource consumption.

  14. Delay Bounded Multi-Source Multicast in Software-Defined Networking

    Directory of Open Access Journals (Sweden)

    Thabo Semong

    2018-01-01

    Full Text Available Software-Defined Networking (SDN is the next generation network architecture with exciting application prospects. The control function in SDN is decoupled from the data forwarding plane, hence it provides a new centralized architecture with flexible network resource management. Although SDN is attracting much attention from both industry and research, its advantage over the traditional networks has not been fully utilized. Multicast is designed to deliver content to multiple destinations. The current traffic engineering in SDN focuses mainly on unicast, however, multicast can effectively reduce network resource consumption by serving multiple clients. This paper studies a novel delay-bounded multi-source multicast SDN problem, in which among the set of potential sources, we select a source to build the multicast-tree, under the constraint that the transmission delay for every destination is bounded. This problem is more difficult than the traditional Steiner minimum tree (SMT problem, since it needs to find a source from the set of all potential sources. We model the problem as a mixed-integer linear programming (MILP and prove its NP-Hardness. To solve the problem, a delay bounded multi-source (DBMS scheme is proposed, which includes a DBMS algorithm to build a minimum delay cost DBMS-Forest. Through a MATLAB experiment, we demonstrate that DBMS is significantly more efficient and outperforms other existing algorithms in the literature.

  15. Data analysis-based autonomic bandwidth adjustment in software defined multi-vendor optical transport networks.

    Science.gov (United States)

    Li, Yajie; Zhao, Yongli; Zhang, Jie; Yu, Xiaosong; Jing, Ruiquan

    2017-11-27

    Network operators generally provide dedicated lightpaths for customers to meet the demand for high-quality transmission. Considering the variation of traffic load, customers usually rent peak bandwidth that exceeds the practical average traffic requirement. In this case, bandwidth provisioning is unmetered and customers have to pay according to peak bandwidth. Supposing that network operators could keep track of traffic load and allocate bandwidth dynamically, bandwidth can be provided as a metered service and customers would pay for the bandwidth that they actually use. To achieve cost-effective bandwidth provisioning, this paper proposes an autonomic bandwidth adjustment scheme based on data analysis of traffic load. The scheme is implemented in a software defined networking (SDN) controller and is demonstrated in the field trial of multi-vendor optical transport networks. The field trial shows that the proposed scheme can track traffic load and realize autonomic bandwidth adjustment. In addition, a simulation experiment is conducted to evaluate the performance of the proposed scheme. We also investigate the impact of different parameters on autonomic bandwidth adjustment. Simulation results show that the step size and adjustment period have significant influences on bandwidth savings and packet loss. A small value of step size and adjustment period can bring more benefits by tracking traffic variation with high accuracy. For network operators, the scheme can serve as technical support of realizing bandwidth as metered service in the future.

  16. Redefining the Indirect Approach, Defining Special Operations Forces (SOF Power, and the Global Networking of SOF

    Directory of Open Access Journals (Sweden)

    Scott Morrison

    2014-07-01

    Full Text Available The current Defense Strategy assigns Special Operations Forces (SOF to play a central role in countering terrorism, weapons of mass destruction, and irregular warfare. However, there has been little published that defines the role of Special Operations alongside air, land, and sea domains. The U.S. Special Operations Community struggles to define its own theoretical concepts such as direct approach and indirect approach. The U.S. SOF circles typically define direct approach with direct action and the indirect approach with foreign internal defense or security force assistance. Military theorist Liddell Hart viewed the indirect approach as a method to orient upon, target, and upset an adversary’s equilibrium in order to plan for and direct decisive blows. Today, the SOF indirect approach is arguable more applicable due to the prevalence of non-state threats and internal conflicts. Following Hart’s definition, precision raids are among the integral components of a broader application of the indirect approach. The approach also networks U.S. government power as a force when used in concert with allies and local partners. Global networking along with balanced precision raids will exponentially increase the utility of SOF power and position it to appropriately complement all domains to tackle 21st century challenges.

  17. A Scheme to Optimize Flow Routing and Polling Switch Selection of Software Defined Networks.

    Directory of Open Access Journals (Sweden)

    Huan Chen

    Full Text Available This paper aims at minimizing the communication cost for collecting flow information in Software Defined Networks (SDN. Since flow-based information collecting method requires too much communication cost, and switch-based method proposed recently cannot benefit from controlling flow routing, jointly optimize flow routing and polling switch selection is proposed to reduce the communication cost. To this end, joint optimization problem is formulated as an Integer Linear Programming (ILP model firstly. Since the ILP model is intractable in large size network, we also design an optimal algorithm for the multi-rooted tree topology and an efficient heuristic algorithm for general topology. According to extensive simulations, it is found that our method can save up to 55.76% communication cost compared with the state-of-the-art switch-based scheme.

  18. Cross-layer shared protection strategy towards data plane in software defined optical networks

    Science.gov (United States)

    Xiong, Yu; Li, Zhiqiang; Zhou, Bin; Dong, Xiancun

    2018-04-01

    In order to ensure reliable data transmission on the data plane and minimize resource consumption, a novel protection strategy towards data plane is proposed in software defined optical networks (SDON). Firstly, we establish a SDON architecture with hierarchical structure of data plane, which divides the data plane into four layers for getting fine-grained bandwidth resource. Then, we design the cross-layer routing and resource allocation based on this network architecture. Through jointly considering the bandwidth resource on all the layers, the SDN controller could allocate bandwidth resource to working path and backup path in an economical manner. Next, we construct auxiliary graphs and transform the shared protection problem into the graph vertex coloring problem. Therefore, the resource consumption on backup paths can be reduced further. The simulation results demonstrate that the proposed protection strategy can achieve lower protection overhead and higher resource utilization ratio.

  19. A Scheme to Optimize Flow Routing and Polling Switch Selection of Software Defined Networks.

    Science.gov (United States)

    Chen, Huan; Li, Lemin; Ren, Jing; Wang, Yang; Zhao, Yangming; Wang, Xiong; Wang, Sheng; Xu, Shizhong

    2015-01-01

    This paper aims at minimizing the communication cost for collecting flow information in Software Defined Networks (SDN). Since flow-based information collecting method requires too much communication cost, and switch-based method proposed recently cannot benefit from controlling flow routing, jointly optimize flow routing and polling switch selection is proposed to reduce the communication cost. To this end, joint optimization problem is formulated as an Integer Linear Programming (ILP) model firstly. Since the ILP model is intractable in large size network, we also design an optimal algorithm for the multi-rooted tree topology and an efficient heuristic algorithm for general topology. According to extensive simulations, it is found that our method can save up to 55.76% communication cost compared with the state-of-the-art switch-based scheme.

  20. Key on demand (KoD) for software-defined optical networks secured by quantum key distribution (QKD).

    Science.gov (United States)

    Cao, Yuan; Zhao, Yongli; Colman-Meixner, Carlos; Yu, Xiaosong; Zhang, Jie

    2017-10-30

    Software-defined optical networking (SDON) will become the next generation optical network architecture. However, the optical layer and control layer of SDON are vulnerable to cyberattacks. While, data encryption is an effective method to minimize the negative effects of cyberattacks, secure key interchange is its major challenge which can be addressed by the quantum key distribution (QKD) technique. Hence, in this paper we discuss the integration of QKD with WDM optical networks to secure the SDON architecture by introducing a novel key on demand (KoD) scheme which is enabled by a novel routing, wavelength and key assignment (RWKA) algorithm. The QKD over SDON with KoD model follows two steps to provide security: i) quantum key pools (QKPs) construction for securing the control channels (CChs) and data channels (DChs); ii) the KoD scheme uses RWKA algorithm to allocate and update secret keys for different security requirements. To test our model, we define a security probability index which measures the security gain in CChs and DChs. Simulation results indicate that the security performance of CChs and DChs can be enhanced by provisioning sufficient secret keys in QKPs and performing key-updating considering potential cyberattacks. Also, KoD is beneficial to achieve a positive balance between security requirements and key resource usage.

  1. Exploring machine-learning-based control plane intrusion detection techniques in software defined optical networks

    Science.gov (United States)

    Zhang, Huibin; Wang, Yuqiao; Chen, Haoran; Zhao, Yongli; Zhang, Jie

    2017-12-01

    In software defined optical networks (SDON), the centralized control plane may encounter numerous intrusion threatens which compromise the security level of provisioned services. In this paper, the issue of control plane security is studied and two machine-learning-based control plane intrusion detection techniques are proposed for SDON with properly selected features such as bandwidth, route length, etc. We validate the feasibility and efficiency of the proposed techniques by simulations. Results show an accuracy of 83% for intrusion detection can be achieved with the proposed machine-learning-based control plane intrusion detection techniques.

  2. Connectivity and dynamics of neuronal networks as defined by the shape of individual neurons

    International Nuclear Information System (INIS)

    Ahnert, Sebastian E; A N Travencolo, Bruno; Costa, Luciano da Fontoura

    2009-01-01

    Biological neuronal networks constitute a special class of dynamical systems, as they are formed by individual geometrical components, namely the neurons. In the existing literature, relatively little attention has been given to the influence of neuron shape on the overall connectivity and dynamics of the emerging networks. The current work addresses this issue by considering simplified neuronal shapes consisting of circular regions (soma/axons) with spokes (dendrites). Networks are grown by placing these patterns randomly in the two-dimensional (2D) plane and establishing connections whenever a piece of dendrite falls inside an axon. Several topological and dynamical properties of the resulting graph are measured, including the degree distribution, clustering coefficients, symmetry of connections, size of the largest connected component, as well as three hierarchical measurements of the local topology. By varying the number of processes of the individual basic patterns, we can quantify relationships between the individual neuronal shape and the topological and dynamical features of the networks. Integrate-and-fire dynamics on these networks is also investigated with respect to transient activation from a source node, indicating that long-range connections play an important role in the propagation of avalanches.

  3. A New Resilience Measure for Supply Chain Networks

    Directory of Open Access Journals (Sweden)

    Ruiying Li

    2017-01-01

    Full Text Available Currently, supply chain networks can span the whole world, and any disruption of these networks may cause economic losses, decreases in sales and unsustainable supplies. Resilience, the ability of the system to withstand disruption and return to a normal state quickly, has become a new challenge during the supply chain network design. This paper defines a new resilience measure as the ratio of the integral of the normalized system performance within its maximum allowable recovery time after the disruption to the integral of the performance in the normal state. Using the maximum allowable recovery time of the system as the time interval under consideration, this measure allows the resilience of different systems to be compared on the same relative scale, and be used under both scenarios that the system can or cannot restore in the given time. Two specific resilience measures, the resilience based on the amount of product delivered and the resilience based on the average delivery distance, are provided for supply chain networks. To estimate the resilience of a given supply chain network, a resilience simulation method is proposed based on the Monte Carlo method. A four-layered hierarchial mobile phone supply chain network is used to illustrate the resilience quantification process and show how network structure affects the resilience of supply chain networks.

  4. Investments in power networks and alternative measures

    International Nuclear Information System (INIS)

    2003-01-01

    Measures taken with respect to production and consumption are often alternatives to investments in the power networks. While decisions about production and consumption are taken in the market, the network operation is subject to monopoly regulation. In the central network, Statnett's commission is to invest on the basis of socioeconomic profitability. There is a need for much better coordination between network investments and other measures in the power system. The price signal from the market and general tariffs are not sufficient to realize optimal solutions, and there is a need for a ''visible hand'' that can contribute to the realization of the solutions that are the best in each individual situation. It is desirable to create processes and incentives that realize the best solutions, independently of dealing with network investments, local power production or other measures.

  5. Toward Measuring Network Aesthetics Based on Symmetry

    Directory of Open Access Journals (Sweden)

    Zengqiang Chen

    2017-05-01

    Full Text Available In this exploratory paper, we discuss quantitative graph-theoretical measures of network aesthetics. Related work in this area has typically focused on geometrical features (e.g., line crossings or edge bendiness of drawings or visual representations of graphs which purportedly affect an observer’s perception. Here we take a very different approach, abandoning reliance on geometrical properties, and apply information-theoretic measures to abstract graphs and networks directly (rather than to their visual representaions as a means of capturing classical appreciation of structural symmetry. Examples are used solely to motivate the approach to measurement, and to elucidate our symmetry-based mathematical theory of network aesthetics.

  6. Physical layer impairments tolerance based lightpath provision in software defined optical network

    Institute of Scientific and Technical Information of China (English)

    Zhao Xianlong; Xu Xianze; Bai Huifeng

    2017-01-01

    As all-optical networks grow with ever increasing ultra-high speed, the communication quality suffers seriously from physical layer impairments ( PLIs) .The same problem still exists in software defined optical network ( SDON) controlled by OpenFlow.Aimed to solve this problem, a PLIs tol-erance based lightpath provision scheme is proposed for OpenFlow controlled optical networks.This proposed approach not only takes the OSNR model to represent those linear PLIs factors, but also in-troduces those nonlinear factors into the OSNR model.Thus, the proposed scheme is able to cover most PLIs factors of each optical link and conduct optical lightpath provison with better communica-tion quality.Moreover, PLIs tolerance model is also set up and considered in this work with some necessary extension to OpenFlow protocols to achieve better compatibility between physical layer im-pairments factors and various services connections.Simulation results show that the proposed scheme is able to get better performance in terms of packet loss rate and connection setup time.

  7. Dynamic Construction Scheme for Virtualization Security Service in Software-Defined Networks.

    Science.gov (United States)

    Lin, Zhaowen; Tao, Dan; Wang, Zhenji

    2017-04-21

    For a Software Defined Network (SDN), security is an important factor affecting its large-scale deployment. The existing security solutions for SDN mainly focus on the controller itself, which has to handle all the security protection tasks by using the programmability of the network. This will undoubtedly involve a heavy burden for the controller. More devastatingly, once the controller itself is attacked, the entire network will be paralyzed. Motivated by this, this paper proposes a novel security protection architecture for SDN. We design a security service orchestration center in the control plane of SDN, and this center physically decouples from the SDN controller and constructs SDN security services. We adopt virtualization technology to construct a security meta-function library, and propose a dynamic security service composition construction algorithm based on web service composition technology. The rule-combining method is used to combine security meta-functions to construct security services which meet the requirements of users. Moreover, the RETE algorithm is introduced to improve the efficiency of the rule-combining method. We evaluate our solutions in a realistic scenario based on OpenStack. Substantial experimental results demonstrate the effectiveness of our solutions that contribute to achieve the effective security protection with a small burden of the SDN controller.

  8. Enhanced method of fast re-routing with load balancing in software-defined networks

    Science.gov (United States)

    Lemeshko, Oleksandr; Yeremenko, Oleksandra

    2017-11-01

    A two-level method of fast re-routing with load balancing in a software-defined network (SDN) is proposed. The novelty of the method consists, firstly, in the introduction of a two-level hierarchy of calculating the routing variables responsible for the formation of the primary and backup paths, and secondly, in ensuring a balanced load of the communication links of the network, which meets the requirements of the traffic engineering concept. The method provides implementation of link, node, path, and bandwidth protection schemes for fast re-routing in SDN. The separation in accordance with the interaction prediction principle along two hierarchical levels of the calculation functions of the primary (lower level) and backup (upper level) routes allowed to abandon the initial sufficiently large and nonlinear optimization problem by transiting to the iterative solution of linear optimization problems of half the dimension. The analysis of the proposed method confirmed its efficiency and effectiveness in terms of obtaining optimal solutions for ensuring balanced load of communication links and implementing the required network element protection schemes for fast re-routing in SDN.

  9. Correlated measurement error hampers association network inference

    NARCIS (Netherlands)

    Kaduk, M.; Hoefsloot, H.C.J.; Vis, D.J.; Reijmers, T.; Greef, J. van der; Smilde, A.K.; Hendriks, M.M.W.B.

    2014-01-01

    Modern chromatography-based metabolomics measurements generate large amounts of data in the form of abundances of metabolites. An increasingly popular way of representing and analyzing such data is by means of association networks. Ideally, such a network can be interpreted in terms of the

  10. Settings in Social Networks : a Measurement Model

    NARCIS (Netherlands)

    Schweinberger, Michael; Snijders, Tom A.B.

    2003-01-01

    A class of statistical models is proposed that aims to recover latent settings structures in social networks. Settings may be regarded as clusters of vertices. The measurement model is based on two assumptions. (1) The observed network is generated by hierarchically nested latent transitive

  11. Centrality measures for immunization of weighted networks

    Directory of Open Access Journals (Sweden)

    Mohammad Khansari

    2016-03-01

    Full Text Available Effective immunization of individual communities with minimal cost in vaccination has made great discussion surrounding the realm of complex networks. Meanwhile, proper realization of relationship among people in society and applying it to social networks brings about substantial improvements in immunization. Accordingly, weighted graph in which link weights represent the intensity and intimacy of relationships is an acceptable approach. In this work we employ weighted graphs and a wide variety of weighted centrality measures to distinguish important individuals in contagion of diseases. Furthermore, we propose new centrality measures for weighted networks. Our experimental results show that Radiality-Degree centrality is satisfying for weighted BA networks. Additionally, PageRank-Degree and Radiality-Degree centralities showmoreacceptable performance in targeted immunization of weighted networks.

  12. Inverting radiometric measurements with a neural network

    Science.gov (United States)

    Measure, Edward M.; Yee, Young P.; Balding, Jeff M.; Watkins, Wendell R.

    1992-02-01

    A neural network scheme for retrieving remotely sensed vertical temperature profiles was applied to observed ground based radiometer measurements. The neural network used microwave radiance measurements and surface measurements of temperature and pressure as inputs. Because the microwave radiometer is capable of measuring 4 oxygen channels at 5 different elevation angles (9, 15, 25, 40, and 90 degs), 20 microwave measurements are potentially available. Because these measurements have considerable redundancy, a neural network was experimented with, accepting as inputs microwave measurements taken at 53.88 GHz, 40 deg; 57.45 GHz, 40 deg; and 57.45, 90 deg. The primary test site was located at White Sands Missile Range (WSMR), NM. Results are compared with measurements made simultaneously with balloon borne radiosonde instruments and with radiometric temperature retrievals made using more conventional retrieval algorithms. The neural network was trained using a Widrow-Hoff delta rule procedure. Functions of date to include season dependence in the retrieval process and functions of time to include diurnal effects were used as inputs to the neural network.

  13. Radioactivity monitoring network: Measurements 1987

    International Nuclear Information System (INIS)

    1989-01-01

    Four papers are presented: radionuclide concentration measurement in aerosols, surface water and the wastes of the Vienna Central Clarification Plant respectively, and on tritium in Austrian lakes and rivers. (qui)

  14. Risk measures on networks and expected utility

    International Nuclear Information System (INIS)

    Cerqueti, Roy; Lupi, Claudio

    2016-01-01

    In reliability theory projects are usually evaluated in terms of their riskiness, and often decision under risk is intended as the one-shot-type binary choice of accepting or not accepting the risk. In this paper we elaborate on the concept of risk acceptance, and propose a theoretical framework based on network theory. In doing this, we deal with system reliability, where the interconnections among the random quantities involved in the decision process are explicitly taken into account. Furthermore, we explore the conditions to be satisfied for risk-acceptance criteria to be consistent with the axiomatization of standard expected utility theory within the network framework. In accordance with existing literature, we show that a risk evaluation criterion can be meaningful even if it is not consistent with the standard axiomatization of expected utility, once this is suitably reinterpreted in the light of networks. Finally, we provide some illustrative examples. - Highlights: • We discuss risk acceptance and theoretically develop this theme on the basis of network theory. • We propose an original framework for describing the algebraic structure of the set of the networks, when they are viewed as risks. • We introduce the risk measures on networks, which induce total orders on the set of networks. • We state conditions on the risk measures on networks to let the induced risk-acceptance criterion be consistent with a new formulation of the expected utility theory.

  15. A Review of Anomaly Detection Techniques and Distributed Denial of Service (DDoS on Software Defined Network (SDN

    Directory of Open Access Journals (Sweden)

    M. H. H. Khairi

    2018-04-01

    Full Text Available Software defined network (SDN is a network architecture in which the network traffic may be operated and managed dynamically according to user requirements and demands. Issue of security is one of the big challenges of SDN because different attacks may affect performance and these attacks can be classified into different types. One of the famous attacks is distributed denial of service (DDoS. SDN is a new networking approach that is introduced with the goal to simplify the network management by separating the data and control planes. However, the separation leads to the emergence of new types of distributed denial-of-service (DDOS attacks on SDN networks. The centralized role of the controller in SDN makes it a perfect target for the attackers. Such attacks can easily bring down the entire network by bringing down the controller. This research explains DDoS attacks and the anomaly detection as one of the famous detection techniques for intelligent networks.

  16. Quantitative Analysis of the Security of Software-Defined Network Controller Using Threat/Effort Model

    Directory of Open Access Journals (Sweden)

    Zehui Wu

    2017-01-01

    Full Text Available SDN-based controller, which is responsible for the configuration and management of the network, is the core of Software-Defined Networks. Current methods, which focus on the secure mechanism, use qualitative analysis to estimate the security of controllers, leading to inaccurate results frequently. In this paper, we employ a quantitative approach to overcome the above shortage. Under the analysis of the controller threat model we give the formal model results of the APIs, the protocol interfaces, and the data items of controller and further provide our Threat/Effort quantitative calculation model. With the help of Threat/Effort model, we are able to compare not only the security of different versions of the same kind controller but also different kinds of controllers and provide a basis for controller selection and secure development. We evaluated our approach in four widely used SDN-based controllers which are POX, OpenDaylight, Floodlight, and Ryu. The test, which shows the similarity outcomes with the traditional qualitative analysis, demonstrates that with our approach we are able to get the specific security values of different controllers and presents more accurate results.

  17. Joint Content Placement and Traffic Management for Cloud Mobile Video Distribution over Software-Defined Networks

    Institute of Scientific and Technical Information of China (English)

    Zhenghuan Zhang; Xiaofeng Jiang; Hongsheng Xi

    2016-01-01

    To cope with the rapid growth of mobile video,video providers have leveraged cloud technologies to deploy their mobile video service system for more cost-effective and scalable performance.The emergence of Software-Defined Networking (SDN) provides a promising solution to manage the underlying network.In this paper,we introduce an SDN-enabled cloud mobile video distribution architecture and propose a joint video placement,request dispatching and traffic management mechanism to improve user experience and reduce the system operational cost.We use a utility function to capture the two aspects of user experience:the level of satisfaction and average latency,and formulate the joint optimization problem as a mixed integer programming problem.We develop an optimal algorithm based on dual decomposition and prove its optimality.We conduct simulations to evaluate the performance of our algorithm and the results show that our strategy can effectively cut down the total cost and guarantee user experience.

  18. Network Compression as a Quality Measure for Protein Interaction Networks

    Science.gov (United States)

    Royer, Loic; Reimann, Matthias; Stewart, A. Francis; Schroeder, Michael

    2012-01-01

    With the advent of large-scale protein interaction studies, there is much debate about data quality. Can different noise levels in the measurements be assessed by analyzing network structure? Because proteomic regulation is inherently co-operative, modular and redundant, it is inherently compressible when represented as a network. Here we propose that network compression can be used to compare false positive and false negative noise levels in protein interaction networks. We validate this hypothesis by first confirming the detrimental effect of false positives and false negatives. Second, we show that gold standard networks are more compressible. Third, we show that compressibility correlates with co-expression, co-localization, and shared function. Fourth, we also observe correlation with better protein tagging methods, physiological expression in contrast to over-expression of tagged proteins, and smart pooling approaches for yeast two-hybrid screens. Overall, this new measure is a proxy for both sensitivity and specificity and gives complementary information to standard measures such as average degree and clustering coefficients. PMID:22719828

  19. Measurement with Persons: A European Network

    NARCIS (Netherlands)

    Pendrill, L.R.; Emardson, R.; Berglund, B.; Gröning, M.; Höglund, A.; Cancedda, A.; Quinti, G.; Crenna, F.; Rossi, G.B.; Drnovek, J.; Gersak, G.; Goodman, T.; Harris, S.; Heijden, van der G.W.A.M.; Kallinen, K.; Ravaja, N.

    2010-01-01

    The European ‘Measuring the Impossible’ Network MINET promotes new research activities in measurement dependent on human perception and/or interpretation. This includes the perceived attributes of products and services, such as quality or desirability, and societal parameters such as security and

  20. Geographically Locating an Internet Node Using Network Latency Measurement

    National Research Council Canada - National Science Library

    Turnbaugh, Eugene

    2004-01-01

    .... The difficulties include accurate latency measure, network address translation (NAT) masking, service blocking, disparate physical configuration, dissimilar network hardware, and inaccurate and limited measuring tools...

  1. A New Wavelength Optimization and Energy-Saving Scheme Based on Network Coding in Software-Defined WDM-PON Networks

    Science.gov (United States)

    Ren, Danping; Wu, Shanshan; Zhang, Lijing

    2016-09-01

    In view of the characteristics of the global control and flexible monitor of software-defined networks (SDN), we proposes a new optical access network architecture dedicated to Wavelength Division Multiplexing-Passive Optical Network (WDM-PON) systems based on SDN. The network coding (NC) technology is also applied into this architecture to enhance the utilization of wavelength resource and reduce the costs of light source. Simulation results show that this scheme can optimize the throughput of the WDM-PON network, greatly reduce the system time delay and energy consumption.

  2. ABS-TrustSDN: An Agent-Based Simulator of Trust Strategies in Software-Defined Networks

    Directory of Open Access Journals (Sweden)

    Iván García-Magariño

    2017-01-01

    Full Text Available Software-defined networks (SDNs have become a mechanism to separate the control plane and the data plane in the communication in networks. SDNs involve several challenges around their security and their confidentiality. Ideally, SDNs should incorporate autonomous and adaptive systems for controlling the routing to be able to isolate network resources that may be malfunctioning or whose security has been compromised with malware. The current work introduces a novel agent-based framework that simulates SDN isolation protocols by means of trust and reputation models. This way, SDN programmers may estimate the repercussions of certain isolation protocols based on trust models before actually deploying the protocol into the network.

  3. Measure of Node Similarity in Multilayer Networks

    DEFF Research Database (Denmark)

    Møllgaard, Anders; Zettler, Ingo; Dammeyer, Jesper

    2016-01-01

    The weight of links in a network is often related to the similarity of thenodes. Here, we introduce a simple tunable measure for analysing the similarityof nodes across different link weights. In particular, we use the measure toanalyze homophily in a group of 659 freshman students at a large...... university.Our analysis is based on data obtained using smartphones equipped with customdata collection software, complemented by questionnaire-based data. The networkof social contacts is represented as a weighted multilayer network constructedfrom different channels of telecommunication as well as data...... might bepresent in one layer of the multilayer network and simultaneously be absent inthe other layers. For a variable such as gender, our measure reveals atransition from similarity between nodes connected with links of relatively lowweight to dis-similarity for the nodes connected by the strongest...

  4. OSiRIS: a distributed Ceph deployment using software defined networking for multi-institutional research

    Science.gov (United States)

    McKee, Shawn; Kissel, Ezra; Meekhof, Benjeman; Swany, Martin; Miller, Charles; Gregorowicz, Michael

    2017-10-01

    We report on the first year of the OSiRIS project (NSF Award #1541335, UM, IU, MSU and WSU) which is targeting the creation of a distributed Ceph storage infrastructure coupled together with software-defined networking to provide high-performance access for well-connected locations on any participating campus. The projects goal is to provide a single scalable, distributed storage infrastructure that allows researchers at each campus to read, write, manage and share data directly from their own computing locations. The NSF CC*DNI DIBBS program which funded OSiRIS is seeking solutions to the challenges of multi-institutional collaborations involving large amounts of data and we are exploring the creative use of Ceph and networking to address those challenges. While OSiRIS will eventually be serving a broad range of science domains, its first adopter will be the LHC ATLAS detector project via the ATLAS Great Lakes Tier-2 (AGLT2) jointly located at the University of Michigan and Michigan State University. Part of our presentation will cover how ATLAS is using the OSiRIS infrastructure and our experiences integrating our first user community. The presentation will also review the motivations for and goals of the project, the technical details of the OSiRIS infrastructure, the challenges in providing such an infrastructure, and the technical choices made to address those challenges. We will conclude with our plans for the remaining 4 years of the project and our vision for what we hope to deliver by the projects end.

  5. National network of radioactivity measurement in environment

    International Nuclear Information System (INIS)

    2006-01-01

    This document constitutes the report of management for the year 2006 of the national network of measurement of radioactivity in environment, instituted by the article R.1333-11 of the Public Health code. According to the 5. of the decree of 27. june 2005, the Institute of radiation protection and nuclear safety (I.R.S.N.) has for mission to write every year a report of management of the national network of radioactivity measurement in environment. This report has for principal objectives: to do an evaluation on organisation and functioning of the piloting committee; to realize a synthesis on the different tasks lead by the working groups; as well as on the human and financial resources devoted to this project; to debrief on the development project of the national network information system. This report must allow to the network actors, as to the professional people and the public, to understand the functioning of the national network and the process implemented for the development of centralization, management and public diffusion tools, of the radioactivity data in environment. The year 2006 was marked by the opening of an Internet gate of the national network. (N.C.)

  6. Spectral Graph Theory Analysis of Software-Defined Networks to Improve Performance and Security

    Science.gov (United States)

    2015-09-01

    too costly to continue operating and administrating them in the same basic manner as standardized by Advanced Research Projects Agency Network...to better monitor the network as compared to network perimeter defenses, such as firewalls and web server demilitarized zones (DMZs). The Open Network

  7. Are self-report measures able to define individuals as physically active or inactive?

    NARCIS (Netherlands)

    Steene-Johannessen, J.; Anderssen, S.A.; Ploeg, H.P. van der; Hendriksen, I.J.M.; Donnelly, A.E.; Brage, S.; Ekelund, U.

    2016-01-01

    Purpose: Assess the agreement between commonly used self-report methods compared with objectively measured physical activity (PA) in defining the prevalence of individuals compliant with PA recommendations. Methods: Time spent in moderate and vigorous PA (MVPA) was measured at two time points in

  8. Measure of Node Similarity in Multilayer Networks.

    Directory of Open Access Journals (Sweden)

    Anders Mollgaard

    Full Text Available The weight of links in a network is often related to the similarity of the nodes. Here, we introduce a simple tunable measure for analysing the similarity of nodes across different link weights. In particular, we use the measure to analyze homophily in a group of 659 freshman students at a large university. Our analysis is based on data obtained using smartphones equipped with custom data collection software, complemented by questionnaire-based data. The network of social contacts is represented as a weighted multilayer network constructed from different channels of telecommunication as well as data on face-to-face contacts. We find that even strongly connected individuals are not more similar with respect to basic personality traits than randomly chosen pairs of individuals. In contrast, several socio-demographics variables have a significant degree of similarity. We further observe that similarity might be present in one layer of the multilayer network and simultaneously be absent in the other layers. For a variable such as gender, our measure reveals a transition from similarity between nodes connected with links of relatively low weight to dis-similarity for the nodes connected by the strongest links. We finally analyze the overlap between layers in the network for different levels of acquaintanceships.

  9. Defining Higher-Order Turbulent Moment Closures with an Artificial Neural Network and Random Forest

    Science.gov (United States)

    McGibbon, J.; Bretherton, C. S.

    2017-12-01

    Unresolved turbulent advection and clouds must be parameterized in atmospheric models. Modern higher-order closure schemes depend on analytic moment closure assumptions that diagnose higher-order moments in terms of lower-order ones. These are then tested against Large-Eddy Simulation (LES) higher-order moment relations. However, these relations may not be neatly analytic in nature. Rather than rely on an analytic higher-order moment closure, can we use machine learning on LES data itself to define a higher-order moment closure?We assess the ability of a deep artificial neural network (NN) and random forest (RF) to perform this task using a set of observationally-based LES runs from the MAGIC field campaign. By training on a subset of 12 simulations and testing on remaining simulations, we avoid over-fitting the training data.Performance of the NN and RF will be assessed and compared to the Analytic Double Gaussian 1 (ADG1) closure assumed by Cloudy Layers Unified By Binormals (CLUBB), a higher-order turbulence closure currently used in the Community Atmosphere Model (CAM). We will show that the RF outperforms the NN and the ADG1 closure for the MAGIC cases within this diagnostic framework. Progress and challenges in using a diagnostic machine learning closure within a prognostic cloud and turbulence parameterization will also be discussed.

  10. Uji Performansi Algoritma Floyd-Warshall Pada Jaringan Software Defined Network (SDN

    Directory of Open Access Journals (Sweden)

    Ihsan Aris Saputra

    2016-12-01

    Full Text Available Penentuan rute pada sebuah jaringan software defined network (SDN merupakan salah satu contoh topik yang menarik untuk diteliti. Algoritma penentuan rute terpendek pada jaringan SDN sangatlah menentukan apakah jaringan SDN yang dibangun dengan algoritma tersebut sudah optimal. Salah satu algoritma penentuan rute terpendek yaitu algoritma FloydWarshall, yang akan diuji coba dan dianalisis apakah sudah termasuk algoritma yang optimal pada jaringan SDN dengan membandingkan dengan standarisasi yang ada. Pengujian akan dilakukan dengan mengirimkan paket data, VoIP dan video dengan melihat overhead traffic dan QoS (delay dan packet loss. Algoritma Floyd-Warshall akan digunakan pada pengontrol Ryu dan menggunakan Mininet sebagai emulator jaringan dengan topologi berbasis Abiline. Hasil simulasi dan pengujian algoritma Floyd-Warshall sebagai penentuan jalur terbaik dalam jaringan SDN, mendapatkan hasil yang memenuhi standarisasi. Nilai dari QoS yang didapat untuk delay masih berada pada nilai yang menjadi standar ITU-T G.1010. Packet loss yang dihasilkan semua jenis layanan sudah memenuhi standar ITU-T G.1010 yaitu 0% hingga saat pada jaringan diberikan background traffic melebihi kapasitas link yaitu pemberian sebesar 75 Mbps. Dalam pengujian waktu konvergensi didapatkan waktu dengan rata-rata nilai 17.71446 detik. Kemudian untuk overhead traffic menunjukan bahwa perubahan overhead dipengaruhi oleh controller update dan juga flow update, dimana ketika sering terjadinya controller update dan flow update maka semakin besar juga overhead yang didapat.

  11. Resting-state test-retest reliability of a priori defined canonical networks over different preprocessing steps.

    Science.gov (United States)

    Varikuti, Deepthi P; Hoffstaedter, Felix; Genon, Sarah; Schwender, Holger; Reid, Andrew T; Eickhoff, Simon B

    2017-04-01

    Resting-state functional connectivity analysis has become a widely used method for the investigation of human brain connectivity and pathology. The measurement of neuronal activity by functional MRI, however, is impeded by various nuisance signals that reduce the stability of functional connectivity. Several methods exist to address this predicament, but little consensus has yet been reached on the most appropriate approach. Given the crucial importance of reliability for the development of clinical applications, we here investigated the effect of various confound removal approaches on the test-retest reliability of functional-connectivity estimates in two previously defined functional brain networks. Our results showed that gray matter masking improved the reliability of connectivity estimates, whereas denoising based on principal components analysis reduced it. We additionally observed that refraining from using any correction for global signals provided the best test-retest reliability, but failed to reproduce anti-correlations between what have been previously described as antagonistic networks. This suggests that improved reliability can come at the expense of potentially poorer biological validity. Consistent with this, we observed that reliability was proportional to the retained variance, which presumably included structured noise, such as reliable nuisance signals (for instance, noise induced by cardiac processes). We conclude that compromises are necessary between maximizing test-retest reliability and removing variance that may be attributable to non-neuronal sources.

  12. Resting-state test-retest reliability of a priori defined canonical networks over different preprocessing steps

    Science.gov (United States)

    Varikuti, Deepthi P.; Hoffstaedter, Felix; Genon, Sarah; Schwender, Holger; Reid, Andrew T.; Eickhoff, Simon B.

    2016-01-01

    Resting-state functional connectivity analysis has become a widely used method for the investigation of human brain connectivity and pathology. The measurement of neuronal activity by functional MRI, however, is impeded by various nuisance signals that reduce the stability of functional connectivity. Several methods exist to address this predicament, but little consensus has yet been reached on the most appropriate approach. Given the crucial importance of reliability for the development of clinical applications, we here investigated the effect of various confound removal approaches on the test-retest reliability of functional-connectivity estimates in two previously defined functional brain networks. Our results showed that grey matter masking improved the reliability of connectivity estimates, whereas de-noising based on principal components analysis reduced it. We additionally observed that refraining from using any correction for global signals provided the best test-retest reliability, but failed to reproduce anti-correlations between what have been previously described as antagonistic networks. This suggests that improved reliability can come at the expense of potentially poorer biological validity. Consistent with this, we observed that reliability was proportional to the retained variance, which presumably included structured noise, such as reliable nuisance signals (for instance, noise induced by cardiac processes). We conclude that compromises are necessary between maximizing test-retest reliability and removing variance that may be attributable to non-neuronal sources. PMID:27550015

  13. Network measures for characterising team adaptation processes

    NARCIS (Netherlands)

    Barth, S.K.; Schraagen, J.M.C.; Schmettow, M.

    2015-01-01

    The aim of this study was to advance the conceptualisation of team adaptation by applying social network analysis (SNA) measures in a field study of a paediatric cardiac surgical team adapting to changes in task complexity and ongoing dynamic complexity. Forty surgical procedures were observed by

  14. Software Defined Networking challenges and future direction: A case study of implementing SDN features on OpenStack private cloud

    International Nuclear Information System (INIS)

    Shamugam, Veeramani; Murray, I; Leong, J A; Sidhu, Amandeep S

    2016-01-01

    Cloud computing provides services on demand instantly, such as access to network infrastructure consisting of computing hardware, operating systems, network storage, database and applications. Network usage and demands are growing at a very fast rate and to meet the current requirements, there is a need for automatic infrastructure scaling. Traditional networks are difficult to automate because of the distributed nature of their decision making process for switching or routing which are collocated on the same device. Managing complex environments using traditional networks is time-consuming and expensive, especially in the case of generating virtual machines, migration and network configuration. To mitigate the challenges, network operations require efficient, flexible, agile and scalable software defined networks (SDN). This paper discuss various issues in SDN and suggests how to mitigate the network management related issues. A private cloud prototype test bed was setup to implement the SDN on the OpenStack platform to test and evaluate the various network performances provided by the various configurations. (paper)

  15. Software Defined Networking challenges and future direction: A case study of implementing SDN features on OpenStack private cloud

    Science.gov (United States)

    Shamugam, Veeramani; Murray, I.; Leong, J. A.; Sidhu, Amandeep S.

    2016-03-01

    Cloud computing provides services on demand instantly, such as access to network infrastructure consisting of computing hardware, operating systems, network storage, database and applications. Network usage and demands are growing at a very fast rate and to meet the current requirements, there is a need for automatic infrastructure scaling. Traditional networks are difficult to automate because of the distributed nature of their decision making process for switching or routing which are collocated on the same device. Managing complex environments using traditional networks is time-consuming and expensive, especially in the case of generating virtual machines, migration and network configuration. To mitigate the challenges, network operations require efficient, flexible, agile and scalable software defined networks (SDN). This paper discuss various issues in SDN and suggests how to mitigate the network management related issues. A private cloud prototype test bed was setup to implement the SDN on the OpenStack platform to test and evaluate the various network performances provided by the various configurations.

  16. Measuring co-authorship and networking-adjusted scientific impact.

    Directory of Open Access Journals (Sweden)

    John P A Ioannidis

    Full Text Available Appraisal of the scientific impact of researchers, teams and institutions with productivity and citation metrics has major repercussions. Funding and promotion of individuals and survival of teams and institutions depend on publications and citations. In this competitive environment, the number of authors per paper is increasing and apparently some co-authors don't satisfy authorship criteria. Listing of individual contributions is still sporadic and also open to manipulation. Metrics are needed to measure the networking intensity for a single scientist or group of scientists accounting for patterns of co-authorship. Here, I define I(1 for a single scientist as the number of authors who appear in at least I(1 papers of the specific scientist. For a group of scientists or institution, I(n is defined as the number of authors who appear in at least I(n papers that bear the affiliation of the group or institution. I(1 depends on the number of papers authored N(p. The power exponent R of the relationship between I(1 and N(p categorizes scientists as solitary (R>2.5, nuclear (R = 2.25-2.5, networked (R = 2-2.25, extensively networked (R = 1.75-2 or collaborators (R<1.75. R may be used to adjust for co-authorship networking the citation impact of a scientist. I(n similarly provides a simple measure of the effective networking size to adjust the citation impact of groups or institutions. Empirical data are provided for single scientists and institutions for the proposed metrics. Cautious adoption of adjustments for co-authorship and networking in scientific appraisals may offer incentives for more accountable co-authorship behaviour in published articles.

  17. Networks of high mutual information define the structural proximity of catalytic sites: implications for catalytic residue identification.

    Directory of Open Access Journals (Sweden)

    Cristina Marino Buslje

    Full Text Available Identification of catalytic residues (CR is essential for the characterization of enzyme function. CR are, in general, conserved and located in the functional site of a protein in order to attain their function. However, many non-catalytic residues are highly conserved and not all CR are conserved throughout a given protein family making identification of CR a challenging task. Here, we put forward the hypothesis that CR carry a particular signature defined by networks of close proximity residues with high mutual information (MI, and that this signature can be applied to distinguish functional from other non-functional conserved residues. Using a data set of 434 Pfam families included in the catalytic site atlas (CSA database, we tested this hypothesis and demonstrated that MI can complement amino acid conservation scores to detect CR. The Kullback-Leibler (KL conservation measurement was shown to significantly outperform both the Shannon entropy and maximal frequency measurements. Residues in the proximity of catalytic sites were shown to be rich in shared MI. A structural proximity MI average score (termed pMI was demonstrated to be a strong predictor for CR, thus confirming the proposed hypothesis. A structural proximity conservation average score (termed pC was also calculated and demonstrated to carry distinct information from pMI. A catalytic likeliness score (Cls, combining the KL, pC and pMI measures, was shown to lead to significantly improved prediction accuracy. At a specificity of 0.90, the Cls method was found to have a sensitivity of 0.816. In summary, we demonstrate that networks of residues with high MI provide a distinct signature on CR and propose that such a signature should be present in other classes of functional residues where the requirement to maintain a particular function places limitations on the diversification of the structural environment along the course of evolution.

  18. Networks of high mutual information define the structural proximity of catalytic sites: implications for catalytic residue identification.

    Science.gov (United States)

    Marino Buslje, Cristina; Teppa, Elin; Di Doménico, Tomas; Delfino, José María; Nielsen, Morten

    2010-11-04

    Identification of catalytic residues (CR) is essential for the characterization of enzyme function. CR are, in general, conserved and located in the functional site of a protein in order to attain their function. However, many non-catalytic residues are highly conserved and not all CR are conserved throughout a given protein family making identification of CR a challenging task. Here, we put forward the hypothesis that CR carry a particular signature defined by networks of close proximity residues with high mutual information (MI), and that this signature can be applied to distinguish functional from other non-functional conserved residues. Using a data set of 434 Pfam families included in the catalytic site atlas (CSA) database, we tested this hypothesis and demonstrated that MI can complement amino acid conservation scores to detect CR. The Kullback-Leibler (KL) conservation measurement was shown to significantly outperform both the Shannon entropy and maximal frequency measurements. Residues in the proximity of catalytic sites were shown to be rich in shared MI. A structural proximity MI average score (termed pMI) was demonstrated to be a strong predictor for CR, thus confirming the proposed hypothesis. A structural proximity conservation average score (termed pC) was also calculated and demonstrated to carry distinct information from pMI. A catalytic likeliness score (Cls), combining the KL, pC and pMI measures, was shown to lead to significantly improved prediction accuracy. At a specificity of 0.90, the Cls method was found to have a sensitivity of 0.816. In summary, we demonstrate that networks of residues with high MI provide a distinct signature on CR and propose that such a signature should be present in other classes of functional residues where the requirement to maintain a particular function places limitations on the diversification of the structural environment along the course of evolution.

  19. Measure of Node Similarity in Multilayer Networks

    DEFF Research Database (Denmark)

    Møllgaard, Anders; Zettler, Ingo; Dammeyer, Jesper

    2016-01-01

    university.Our analysis is based on data obtained using smartphones equipped with customdata collection software, complemented by questionnaire-based data. The networkof social contacts is represented as a weighted multilayer network constructedfrom different channels of telecommunication as well as data...... might bepresent in one layer of the multilayer network and simultaneously be absent inthe other layers. For a variable such as gender, our measure reveals atransition from similarity between nodes connected with links of relatively lowweight to dis-similarity for the nodes connected by the strongest...

  20. Traffic measurement for big network data

    CERN Document Server

    Chen, Shigang; Xiao, Qingjun

    2017-01-01

    This book presents several compact and fast methods for online traffic measurement of big network data. It describes challenges of online traffic measurement, discusses the state of the field, and provides an overview of the potential solutions to major problems. The authors introduce the problem of per-flow size measurement for big network data and present a fast and scalable counter architecture, called Counter Tree, which leverages a two-dimensional counter sharing scheme to achieve far better memory efficiency and significantly extend estimation range. Unlike traditional approaches to cardinality estimation problems that allocate a separated data structure (called estimator) for each flow, this book takes a different design path by viewing all the flows together as a whole: each flow is allocated with a virtual estimator, and these virtual estimators share a common memory space. A framework of virtual estimators is designed to apply the idea of sharing to an array of cardinality estimation solutions, achi...

  1. Computer Network Availability at Sandia National Laboratories, Albuquerque NM: Measurement and Perception; TOPICAL

    International Nuclear Information System (INIS)

    NELSON, SPENCER D.; TOLENDINO, LAWRENCE F.

    1999-01-01

    The desire to provide a measure of computer network availability at Sandia National Laboratories has existed for along time. Several attempts were made to build this measure by accurately recording network failures, identifying the type of network element involved, the root cause of the problem, and the time to repair the fault. Recognizing the limitations of available methods, it became obvious that another approach of determining network availability had to be defined. The chosen concept involved the periodic sampling of network services and applications from various network locations. A measure of ''network'' availability was then calculated based on the ratio of polling success to failure. The effort required to gather the information and produce a useful metric is not prohibitive and the information gained has verified long held feelings regarding network performance with real data

  2. SOFTWARE DEFINED NETWORKS (SDN): APPROACHES NEEDED FOR UP-GRADATION OF SDN'S

    OpenAIRE

    Deepak Kumar*, Manu Sood

    2017-01-01

    SDN has changed the way of thinking about networks. SDN networks are flexible, scalable and easily manageable. Application that runs on the management plane actually utilize the network efficiency, So application developed should be capable of handling the controllers functionality. Each of the application that runs should be free from viruses, so that it does not affect the controller. Also we need to increase the level of security in all layers of the SDN architecture. SDN is growing faster...

  3. Guidelines for defining and documenting data on costs of possible environmental protection measures

    Energy Technology Data Exchange (ETDEWEB)

    Marlowe, I.; King, K.; Boyd, R.; Bouscaren, R.; Pacyna, J. [AEA Technology Environment, Harwell (United Kingdom)

    1999-07-01

    The Guidelines are intended to promote good practice in the documenting and use of data on the costs of possible environmental protection measures in the context of international data comparisons. The minimum information needed to describe the cost of an environmental protection measures is: details of pollution source; details of the environmental protection measure and its performance characteristics; how costs are defined; the year to which data apply; indications of data uncertainty; how pollutants are defined; and reference to data sources. Guidelines are given for these seven items. These are followed by descriptions of various methods of data processing - dealing with information; calculating annual costs; discount/interest rates; and additional issues relating to the implementation of cost data. 16 refs., 5 tabs., 6 apps.

  4. Toward defining and measuring social accountability in graduate medical education: a stakeholder study.

    Science.gov (United States)

    Reddy, Anjani T; Lazreg, Sonia A; Phillips, Robert L; Bazemore, Andrew W; Lucan, Sean C

    2013-09-01

    Since 1965, Medicare has publically financed graduate medical education (GME) in the United States. Given public financing, various advisory groups have argued that GME should be more socially accountable. Several efforts are underway to develop accountability measures for GME that could be tied to Medicare payments, but it is not clear how to measure or even define social accountability. We explored how GME stakeholders perceive, define, and measure social accountability. Through purposive and snowball sampling, we completed semistructured interviews with 18 GME stakeholders from GME training sites, government agencies, and health care organizations. We analyzed interview field notes and audiorecordings using a flexible, iterative, qualitative group process to identify themes. THREE THEMES EMERGED IN REGARDS TO DEFINING SOCIAL ACCOUNTABILITY: (1) creating a diverse physician workforce to address regional needs and primary care and specialty shortages; (2) ensuring quality in training and care to best serve patients; and (3) providing service to surrounding communities and the general public. All but 1 stakeholder believed GME institutions have a responsibility to be socially accountable. Reported barriers to achieving social accountability included training time constraints, financial limitations, and institutional resistance. Suggestions for measuring social accountability included reviewing graduates' specialties and practice locations, evaluating curricular content, and reviewing program services to surrounding communities. Most stakeholders endorsed the concept of social accountability in GME, suggesting definitions and possible measures that could inform policy makers calls for increased accountability despite recognized barriers.

  5. Defining Tolerance: Impacts of Delay and Disruption when Managing Challenged Networks

    Science.gov (United States)

    Birrane, Edward J. III; Burleigh, Scott C.; Cerf, Vint

    2011-01-01

    Challenged networks exhibit irregularities in their communication performance stemming from node mobility, power constraints, and impacts from the operating environment. These irregularities manifest as high signal propagation delay and frequent link disruption. Understanding those limits of link disruption and propagation delay beyond which core networking features fail is an ongoing area of research. Various wireless networking communities propose tools and techniques that address these phenomena. Emerging standardization activities within the Internet Research Task Force (IRTF) and the Consultative Committee for Space Data Systems (CCSDS) look to build upon both this experience and scalability analysis. Successful research in this area is predicated upon identifying enablers for common communication functions (notably node discovery, duplex communication, state caching, and link negotiation) and how increased disruptions and delays affect their feasibility within the network. Networks that make fewer assumptions relating to these enablers provide more universal service. Specifically, reliance on node discovery and link negotiation results in network-specific operational concepts rather than scalable technical solutions. Fundamental to this debate are the definitions, assumptions, operational concepts, and anticipated scaling of these networks. This paper presents the commonalities and differences between delay and disruption tolerance, including support protocols and critical enablers. We present where and how these tolerances differ. We propose a set of use cases that must be accommodated by any standardized delay-tolerant network and discuss the implication of these on existing tool development.

  6. Conceptual Considerations for Reducing the Computational Complexity in Software Defined Radio using Cooperative Wireless Networks

    DEFF Research Database (Denmark)

    Kristensen, Jesper Michael; Fitzek, Frank H. P.; Koch, Peter

    2005-01-01

    the expected increase in complexity leading to a decrease in energy efficiency, cooperative wireless networks are introduced. Cooperative wireless networks enables the concept of resource sharing. Resource sharing is interpreted as collaborative signal processing. This interpretation leads to the concept...... of a distributed signal processor. OFDM and the principle of FFT is described as an example of collaborative signal processing....

  7. Measuring structural similarity in large online networks.

    Science.gov (United States)

    Shi, Yongren; Macy, Michael

    2016-09-01

    Structural similarity based on bipartite graphs can be used to detect meaningful communities, but the networks have been tiny compared to massive online networks. Scalability is important in applications involving tens of millions of individuals with highly skewed degree distributions. Simulation analysis holding underlying similarity constant shows that two widely used measures - Jaccard index and cosine similarity - are biased by the distribution of out-degree in web-scale networks. However, an alternative measure, the Standardized Co-incident Ratio (SCR), is unbiased. We apply SCR to members of Congress, musical artists, and professional sports teams to show how massive co-following on Twitter can be used to map meaningful affiliations among cultural entities, even in the absence of direct connections to one another. Our results show how structural similarity can be used to map cultural alignments and demonstrate the potential usefulness of social media data in the study of culture, politics, and organizations across the social and behavioral sciences. Copyright © 2016 Elsevier Inc. All rights reserved.

  8. Gene networks specific for innate immunity define post-traumatic stress disorder.

    Science.gov (United States)

    Breen, M S; Maihofer, A X; Glatt, S J; Tylee, D S; Chandler, S D; Tsuang, M T; Risbrough, V B; Baker, D G; O'Connor, D T; Nievergelt, C M; Woelk, C H

    2015-12-01

    The molecular factors involved in the development of Post-Traumatic Stress Disorder (PTSD) remain poorly understood. Previous transcriptomic studies investigating the mechanisms of PTSD apply targeted approaches to identify individual genes under a cross-sectional framework lack a holistic view of the behaviours and properties of these genes at the system-level. Here we sought to apply an unsupervised gene-network based approach to a prospective experimental design using whole-transcriptome RNA-Seq gene expression from peripheral blood leukocytes of U.S. Marines (N=188), obtained both pre- and post-deployment to conflict zones. We identified discrete groups of co-regulated genes (i.e., co-expression modules) and tested them for association to PTSD. We identified one module at both pre- and post-deployment containing putative causal signatures for PTSD development displaying an over-expression of genes enriched for functions of innate-immune response and interferon signalling (Type-I and Type-II). Importantly, these results were replicated in a second non-overlapping independent dataset of U.S. Marines (N=96), further outlining the role of innate immune and interferon signalling genes within co-expression modules to explain at least part of the causal pathophysiology for PTSD development. A second module, consequential of trauma exposure, contained PTSD resiliency signatures and an over-expression of genes involved in hemostasis and wound responsiveness suggesting that chronic levels of stress impair proper wound healing during/after exposure to the battlefield while highlighting the role of the hemostatic system as a clinical indicator of chronic-based stress. These findings provide novel insights for early preventative measures and advanced PTSD detection, which may lead to interventions that delay or perhaps abrogate the development of PTSD.

  9. Defining and Measuring Cognitive-Entropy and Cognitive Self-Synchronization

    Science.gov (United States)

    2011-06-01

    16th ICCRTS: “Collective C2 in Multinational Civil-Military Operations” Defining and Measuring Cognitive-Entropy and Cognitive Self- Synchronization ...shared awareness and enabling self- synchronization across the range of participating entities (Alberts and Hayes 2009, pp.106). We consider the...aspect of self- synchronization (Alberts and Hayes, 2006) a key one in the context of modern operations and in performing C2 assessments. Based on (Manso

  10. Defining a convergence network platform framework for smart grid and intelligent transport systems

    International Nuclear Information System (INIS)

    Coronado Mondragon, Adrian E.; Coronado, Etienne S.; Coronado Mondragon, Christian E.

    2015-01-01

    The challenges faced by electricity grids suggest smart grids will have to coordinate its operation with other important initiatives in areas such as transportation. The smart grid relies on the use of network platforms where meter readings and data can be transmitted. On the other hand, concerning transportation systems the need to achieve a reduction of road congestion and traffic accidents among the increasing use of electric vehicles has consolidated the importance of ITS (intelligent transport systems). Given the magnitude of the challenges faced by both the smart grid and ITS, the aim of this work is to identify the elements comprising a convergence platform capable of supporting future services for data traffic associated to smart grid operations as well as ITS-related commercial service applications and road traffic safety messaging. A seaport terminal scenario is used to present a convergence network platform incorporating WSN (wireless sensor network) theory. The results of the simulation of the proposed network confirms the suitability of WSN to be used in the transmission of data traffic associated to meter readings which is required for effective energy consumption and management policies in industrial environments comprising equipment with high energy demands. - Highlights: • Common needs/challenges of smart grid/ITS can be addressed by a convergence network platform. • VANETs are identified as key components of the smart grid/ITS convergence network platform. • WSN (Wireless Sensor Network) theory is suitable for the transmission of data traffic associated to meter readings. • The amount of energy supplied to the network is low but enough to support data traffic required in industrial environments. • WSN supports the steady exchange of packets as characterized in industrial environments like seaports

  11. Security in software-defined wireless sensor networks: threats, challenges and potential solutions

    CSIR Research Space (South Africa)

    Pritchard, SW

    2017-07-01

    Full Text Available have focused on low resource cryptography methods to secure the network [27] - [29], [33]. Cryptography methods are separated into symmetric cryptography and asymmetric cryptography. While symmetric cryptography solutions are preferred due to low... implementation cost and efficiency [5], they present many problems when managing large networks and attempts to improve this cryptography for WSNs [11] have resulted in the cost of resources. Symmetric cryptography is also difficult to implement in software...

  12. A Taxonomy for Software Defined Networking, Man In The Middle Attacks

    Science.gov (United States)

    2016-09-01

    that separates it from the networks of today’s world . As Stallings (2013) describes, “current networks are vertically integrated, meaning that the data...cause overpopulation of flow tables increasing processing rate on the switch (Zarek, 2012). More specifically, premature evictions result 16 in...Mininet demonstrated our proof of concept but was not sufficient for real world implementation. Our overall goal was to grab an HTTP response packet

  13. Software-Defined Radio Global System for Mobile Communications Transmitter Development for Heterogeneous Network Vulnerability Testing

    Science.gov (United States)

    2013-12-01

    AbdelWahab, “ 2G / 3G Inter-RAT Handover Performance Analysis,” Second European Conference on Antennas and Propagation, pp. 1, 8, 11–16, Nov. 2007. [19] J...RADIO GLOBAL SYSTEM FOR MOBILE COMMUNICATIONS TRANSMITTER DEVELOPMENT FOR HETEROGENEOUS NETWORK VULNERABILITY TESTING by Carson C. McAbee... MOBILE COMMUNICATIONS TRANSMITTER DEVELOPMENT FOR HETEROGENEOUS NETWORK VULNERABILITY TESTING 5. FUNDING NUMBERS 6. AUTHOR(S) Carson C. McAbee

  14. Measuring co-authorship and networking-adjusted scientific impact.

    Science.gov (United States)

    Ioannidis, John P A

    2008-07-23

    Appraisal of the scientific impact of researchers, teams and institutions with productivity and citation metrics has major repercussions. Funding and promotion of individuals and survival of teams and institutions depend on publications and citations. In this competitive environment, the number of authors per paper is increasing and apparently some co-authors don't satisfy authorship criteria. Listing of individual contributions is still sporadic and also open to manipulation. Metrics are needed to measure the networking intensity for a single scientist or group of scientists accounting for patterns of co-authorship. Here, I define I(1) for a single scientist as the number of authors who appear in at least I(1) papers of the specific scientist. For a group of scientists or institution, I(n) is defined as the number of authors who appear in at least I(n) papers that bear the affiliation of the group or institution. I(1) depends on the number of papers authored N(p). The power exponent R of the relationship between I(1) and N(p) categorizes scientists as solitary (R>2.5), nuclear (R = 2.25-2.5), networked (R = 2-2.25), extensively networked (R = 1.75-2) or collaborators (Raccountable co-authorship behaviour in published articles.

  15. Burst switching without guard interval in all-optical software-define star intra-data center network

    Science.gov (United States)

    Ji, Philip N.; Wang, Ting

    2014-02-01

    Optical switching has been introduced in intra-data center networks (DCNs) to increase capacity and to reduce power consumption. Recently we proposed a star MIMO OFDM-based all-optical DCN with burst switching and software-defined networking. Here, we introduce the control procedure for the star DCN in detail for the first time. The timing, signaling, and operation are described for each step to achieve efficient bandwidth resource utilization. Furthermore, the guidelines for the burst assembling period selection that allows burst switching without guard interval are discussed. The star all-optical DCN offers flexible and efficient control for next-generation data center application.

  16. The synaptic properties of cells define the hallmarks of interval timing in a recurrent neural network.

    Science.gov (United States)

    Pérez, Oswaldo; Merchant, Hugo

    2018-04-03

    Extensive research has described two key features of interval timing. The bias property is associated with accuracy and implies that time is overestimated for short intervals and underestimated for long intervals. The scalar property is linked to precision and states that the variability of interval estimates increases as a function of interval duration. The neural mechanisms behind these properties are not well understood. Here we implemented a recurrent neural network that mimics a cortical ensemble and includes cells that show paired-pulse facilitation and slow inhibitory synaptic currents. The network produces interval selective responses and reproduces both bias and scalar properties when a Bayesian decoder reads its activity. Notably, the interval-selectivity, timing accuracy, and precision of the network showed complex changes as a function of the decay time constants of the modeled synaptic properties and the level of background activity of the cells. These findings suggest that physiological values of the time constants for paired-pulse facilitation and GABAb, as well as the internal state of the network, determine the bias and scalar properties of interval timing. Significant Statement Timing is a fundamental element of complex behavior, including music and language. Temporal processing in a wide variety of contexts shows two primary features: time estimates exhibit a shift towards the mean (the bias property) and are more variable for longer intervals (the scalar property). We implemented a recurrent neural network that includes long-lasting synaptic currents, which can not only produce interval selective responses but also follow the bias and scalar properties. Interestingly, only physiological values of the time constants for paired-pulse facilitation and GABAb, as well as intermediate background activity within the network can reproduce the two key features of interval timing. Copyright © 2018 the authors.

  17. Current and emerging approaches to define intestinal epithelium-specific transcriptional networks

    DEFF Research Database (Denmark)

    Olsen, Anders Krüger; Boyd, Mette; Danielsen, Erik Thomas

    2012-01-01

    Upon developmental or environmental cues, the composition of transcription factors in a transcriptional regulatory network is deeply implicated in controlling the signature of the gene expression and thereby specifies the cell or tissue type. Novel methods including ChIP-chip and ChIP-Seq have been...

  18. Current and emerging approaches to define intestinal epithelium-specific transcriptional networks

    DEFF Research Database (Denmark)

    Olsen, Anders Krûger; Boyd, Mette; Danielsen, Erik Thomas

    2012-01-01

    Upon developmental or environmental cues, the composition of transcription factors in a transcriptional regulatory network is deeply implicated in controlling the signature of the gene expression and thereby specifies the cell- or tissue-type. Novel methods including ChIP-chip and ChIP-Seq have...

  19. Dead end metabolites--defining the known unknowns of the E. coli metabolic network.

    Directory of Open Access Journals (Sweden)

    Amanda Mackie

    Full Text Available The EcoCyc database is an online scientific database which provides an integrated view of the metabolic and regulatory network of the bacterium Escherichia coli K-12 and facilitates computational exploration of this important model organism. We have analysed the occurrence of dead end metabolites within the database--these are metabolites which lack the requisite reactions (either metabolic or transport that would account for their production or consumption within the metabolic network. 127 dead end metabolites were identified from the 995 compounds that are contained within the EcoCyc metabolic network. Their presence reflects either a deficit in our representation of the network or in our knowledge of E. coli metabolism. Extensive literature searches resulted in the addition of 38 transport reactions and 3 metabolic reactions to the database and led to an improved representation of the pathway for Vitamin B12 salvage. 39 dead end metabolites were identified as components of reactions that are not physiologically relevant to E. coli K-12--these reactions are properties of purified enzymes in vitro that would not be expected to occur in vivo. Our analysis led to improvements in the software that underpins the database and to the program that finds dead end metabolites within EcoCyc. The remaining dead end metabolites in the EcoCyc database likely represent deficiencies in our knowledge of E. coli metabolism.

  20. VPN (Virtual Private Network) Performance Measurements

    Energy Technology Data Exchange (ETDEWEB)

    Calderon, Calixto; Goncalves, Joao G.M.; Sequeira, Vitor [Joint Research Centre, Ispra (Italy). Inst. for the Protection and Security of the Citizen; Vandaele, Roland; Meylemans, Paul [European Commission, DG-TREN (Luxembourg)

    2003-05-01

    Virtual Private Networks (VPN) is an important technology allowing for secure communications through insecure transmission media (i.e., Internet) by adding authentication and encryption to the existing protocols. This paper describes some VPN performance indicators measured over international communication links. An ISDN based VPN link was established between the Joint Research Centre, Ispra site, Italy, and EURATOM Safeguards in Luxembourg. This link connected two EURATOM Safeguards FAST surveillance stations, and used different vendor solutions hardware (Cisco router 1720 and Nokia CC-500 Gateway). To authenticate and secure this international link, we have used several methods at the different levels of the seven-layered ISO network protocol stack (i.e., Callback feature, CHAP - Challenge Handshake Protocol - authentication protocol). The tests made involved the use of different encryption algorithms and the way session secret keys are periodically renewed, considering these elements influence significantly the transmission throughput. Future tests will include the use of a wide variety of wireless media transmission and terminal equipment technologies, in particular PDAs (Personal Digital Assistants) and Notebook PCs. These tests aim at characterising the functionality of VPNs whenever field inspectors wish to contact headquarters to access information from a central archive database or transmit local measurements or documents. These technologies cover wireless transmission needs at different geographical scales: roombased level Bluetooth, floor or building level Wi-Fi and region or country level GPRS.

  1. A Network Analysis of the American Library Association: Defining a Profession

    Science.gov (United States)

    Battleson, Brenda L.

    2010-01-01

    The term "librarianship" is a generic one, suggesting one overarching discipline despite the numerous specializations and areas of research within the profession. While many disciplines use bibliometric analysis of their literature to define subfields of study within, such methods are not appropriate to librarianship due to the nature of…

  2. De-optical-line-terminal hybrid access-aggregation optical network for time-sensitive services based on software-defined networking orchestration

    Science.gov (United States)

    Bai, Wei; Yang, Hui; Xiao, Hongyun; Yu, Ao; He, Linkuan; Zhang, Jie; Li, Zhen; Du, Yi

    2017-11-01

    With the increase in varieties of services in network, time-sensitive services (TSSs) appear and bring forward an impending need for delay performance. Ultralow-latency communication has become one of the important development goals for many scenarios in the coming 5G era (e.g., robotics and driverless cars). However, the conventional methods, which decrease delay by promoting the available resources and the network transmission speed, have limited effect; a new breakthrough for ultralow-latency communication is necessary. We propose a de-optical-line-terminal (De-OLT) hybrid access-aggregation optical network (DAON) for TSS based on software-defined networking (SDN) orchestration. In this network, low-latency all-optical communication based on optical burst switching can be achieved by removing OLT. For supporting this network and guaranteeing the quality of service for TSSs, we design SDN-driven control method and service provision method. Numerical results demonstrate the proposed DAON promotes network service efficiency and avoids traffic congestion.

  3. Application of the ETOM framework for defining processes in the telecommunication systems management network of the Serbian Army

    Directory of Open Access Journals (Sweden)

    Vladimir B. Suša

    2013-10-01

    Full Text Available This paper deals with management system requirements in telecommunications. A TMN (Telecommunication Management Network is necessary to be well designed and constantly upgraded. The  ETOM (Enhanced Telecommunication Operation Map framework, defined by the ITU-T Recommendation M.3050, is used to describe various processes that occur in the network for monitoring and control of military telecommunications systems. Their definition is an essential precondition for introducing management applications that would manage all of the processes in their end-to-end structure. Telecommunication networks are categorized in  accordance withg their functions. A set of relevant network processes important for supervision and management is explained for each described subsystem. This defining represents a prerequisite for the management application configuration which aims to automate management functions and services. eTOM frame and its implementation in telecommunication management networks ETOM is defined as a telecommunication conceptual frame which includes all the processes that exist in a telecommunication network. It does not represent a telecommunication model, but gives a basic frame for all the processes to be included within. It ranges throughout three basic areas: operation processes, planning and development processes and production management. ETOM supports two different process grouping perspectives: horizontal and vertical. The aim of this kind of grouping is to provide the complete overview in all the processes a telecommunication management network should include. Horizontal grouping includes functional processes within the same managed system. Vertical grouping includes all the processes within a TMN. Overlapped horizontal and vertical group constellations enable a connected matrix structure of the eTOM frame. Operational processes within a TMN can be divided into a few categories: user-network interaction, services management and

  4. Threat Landscape and Good Practice Guide for Software Defined Networks/5G

    OpenAIRE

    Belmonte Martin, A.; Marinos, L.; Rekleitis, E.; Spanoudakis, G.; Petroulakis, N. E.

    2015-01-01

    5G represents the next major phase of mobile telecommunication systems and network architectures beyond the current 4G standards, aiming at extreme broadband and ultra-robust, low latency connectivity, to enable the programmable connectivity for the Internet of Everything2. Despite the significant debate on the technical specifications and the technological maturity of 5G, which are under discussion in various fora3, 5G is expected to affect positively and significantly several industry secto...

  5. System Energy Assessment (SEA, Defining a Standard Measure of EROI for Energy Businesses as Whole Systems

    Directory of Open Access Journals (Sweden)

    Jay Zarnikau

    2011-10-01

    Full Text Available A more objective method for measuring the energy needs of businesses, System Energy Assessment (SEA, measures the combined impacts of material supply chains and service supply chains, to assess businesses as whole self-managing net-energy systems. The method is demonstrated using a model Wind Farm, and defines a physical measure of their energy productivity for society (EROI-S, a ratio of total energy delivered to total energy expended. Energy use records for technology and proxy measures for clearly understood but not individually recorded energy uses for services are combined for a whole system estimate of consumption required for production. Current methods count only energy needs for technology. Business services outsource their own energy needs to operate, leaving no traceable record. That uncounted business energy demand is often 80% of the total, an amount of “dark energy” hidden from view, discovered by finding the average energy estimated needs for businesses far below the world average energy consumed per dollar of GDP. Presently for lack of information the energy needs of business services are counted to be “0”. Our default assumption is to treat them as “average”. The result is a hard measure of total business demand for energy services, a “Scope 4” energy use or GHG impact assessment. Counting recorded energy uses and discounting unrecorded ones misrepresents labor intensive work as highly energy efficient. The result confirms a similar finding by Hall et al. in 1981 [1]. We use exhaustive search for what a business needs to operate as a whole, tracing internal business relationships rather than energy data, to locate its natural physical boundary as a working unit, and so define a business as a physical rather than statistical subject of scientific study. See also online resource materials and notes [2].

  6. The cancer cell map initiative: defining the hallmark networks of cancer.

    Science.gov (United States)

    Krogan, Nevan J; Lippman, Scott; Agard, David A; Ashworth, Alan; Ideker, Trey

    2015-05-21

    Progress in DNA sequencing has revealed the startling complexity of cancer genomes, which typically carry thousands of somatic mutations. However, it remains unclear which are the key driver mutations or dependencies in a given cancer and how these influence pathogenesis and response to therapy. Although tumors of similar types and clinical outcomes can have patterns of mutations that are strikingly different, it is becoming apparent that these mutations recurrently hijack the same hallmark molecular pathways and networks. For this reason, it is likely that successful interpretation of cancer genomes will require comprehensive knowledge of the molecular networks under selective pressure in oncogenesis. Here we announce the creation of a new effort, The Cancer Cell Map Initiative (CCMI), aimed at systematically detailing these complex interactions among cancer genes and how they differ between diseased and healthy states. We discuss recent progress that enables creation of these cancer cell maps across a range of tumor types and how they can be used to target networks disrupted in individual patients, significantly accelerating the development of precision medicine. Copyright © 2015 Elsevier Inc. All rights reserved.

  7. Effective distance adaptation traffic dispatching in software defined IP over optical network

    Science.gov (United States)

    Duan, Zhiwei; Li, Hui; Liu, Yuze; Ji, Yuefeng; Li, Hongfa; Lin, Yi

    2017-10-01

    The rapid growth of IP traffic has contributed to the wide deployment of optical devices (ROADM/OXC, etc.). Meanwhile, with the emergence and application of high-performance network services such as ultra-high video transmission, people are increasingly becoming more and more particular about the quality of service (QoS) of network. However, the pass-band shape of WSSs which is utilized in the ROADM/OXC is not ideal, causing narrowing of spectrum. Spectral narrowing can lead to signal impairment. Therefore, guard-bands need to be inserted between adjacent paths. In order to minimize the bandwidth waste due to guard bands, we propose an effective distance-adaptation traffic dispatching algorithm in IP over optical network based on SDON architecture. We use virtualization technology to set up virtual resources direct links by extracting part of the resources on paths which meet certain specific constraints. We also assign different bandwidth to each IP request based on path length. There is no need for guard-bands between the adjacent paths on the virtual link, which can effectively reduce the number of guard-bands and save the spectrum.

  8. Measuring replication competent HIV-1: advances and challenges in defining the latent reservoir.

    Science.gov (United States)

    Wang, Zheng; Simonetti, Francesco R; Siliciano, Robert F; Laird, Gregory M

    2018-02-13

    Antiretroviral therapy cannot cure HIV-1 infection due to the persistence of a small number of latently infected cells harboring replication-competent proviruses. Measuring persistent HIV-1 is challenging, as it consists of a mosaic population of defective and intact proviruses that can shift from a state of latency to active HIV-1 transcription. Due to this complexity, most of the current assays detect multiple categories of persistent HIV-1, leading to an overestimate of the true size of the latent reservoir. Here, we review the development of the viral outgrowth assay, the gold-standard quantification of replication-competent proviruses, and discuss the insights provided by full-length HIV-1 genome sequencing methods, which allowed us to unravel the composition of the proviral landscape. In this review, we provide a dissection of what defines HIV-1 persistence and we examine the unmet needs to measure the efficacy of interventions aimed at eliminating the HIV-1 reservoir.

  9. Defining Neighbourhoods as a Measure of Exposure to the Food Environment

    Directory of Open Access Journals (Sweden)

    Anders K. Lyseen

    2015-07-01

    Full Text Available Neighbourhoods are frequently used as a measure for individuals’ exposure to the food environment. However, the definitions of neighbourhoods fluctuate and have not been applied consistently in previous studies. Neighbourhoods defined from a single fixed location fail to capture people’s complete exposure in multiple locations, but measuring behaviour using traditional methods can be challenging. This study compares the traditional methods of measuring exposure to the food environment to methods that use data from GPS tracking. For each of the 187 participants, 11 different neighbourhoods were created in which the exposure to supermarkets and fast food outlets were measured. ANOVA, Tukey’s Honestly Significant Difference (HSD test and t-tests were performed to compare the neighbourhoods. Significant differences were found between area sizes and the exposure to supermarkets and fast food outlets for different neighbourhood types. Second, significant differences in exposure to food outlets were found between the urban and rural neighbourhoods. Neighbourhoods are clearly a diffused and blurred concept that varies in meaning depending on each person’s perception and the conducted study. Complexity and heterogeneity of human mobility no longer appear to correspond to the use of residential neighbourhoods but rather emphasise the need for methods, concepts and measures of individual activity and exposure.

  10. In-Network Data Processing in Software-Defined IoT with a Programmable Data Plane

    Directory of Open Access Journals (Sweden)

    Ki-Wook Kim

    2018-01-01

    Full Text Available Making an SDN data plane flexible enough to satisfy the various requirements of heterogeneous IoT applications is very desirable in terms of software-defined IoT (SD-IoT networking. Network devices with a programmable data plane provide an ability to dynamically add new packet- and data-processing procedures to IoT applications. The previously proposed solutions for the addition of the programmability feature to the SDN data plane provide extensibility for the packet-forwarding operations of new protocols, but IoT applications need a more flexible programmability for in-network data-processing operations (e.g., the sensing-data aggregation from thousands of sensor nodes. Moreover, some IoT models such as OMG DDS, oneM2M, and Eclipse SCADA use the publish-subscribe model that is difficult to represent using the operations of the existing message-centric data-plane models. We introduce a new in-network data-processing scheme for the SD-IoT data plane that defines an event-driven data-processing model that can express a variety of in-network data-processing cases in the SD-IoT environment. Also, the proposed model comprises a language for the programming of the data-processing procedures, while a flexible data-plane structure that can install and execute the programs at runtime is additionally presented. We demonstrate the flexibility of the proposed scheme by using sample programs in a number of example SD-IoT cases.

  11. Measuring the evolutionary rewiring of biological networks.

    Directory of Open Access Journals (Sweden)

    Chong Shou

    Full Text Available We have accumulated a large amount of biological network data and expect even more to come. Soon, we anticipate being able to compare many different biological networks as we commonly do for molecular sequences. It has long been believed that many of these networks change, or "rewire", at different rates. It is therefore important to develop a framework to quantify the differences between networks in a unified fashion. We developed such a formalism based on analogy to simple models of sequence evolution, and used it to conduct a systematic study of network rewiring on all the currently available biological networks. We found that, similar to sequences, biological networks show a decreased rate of change at large time divergences, because of saturation in potential substitutions. However, different types of biological networks consistently rewire at different rates. Using comparative genomics and proteomics data, we found a consistent ordering of the rewiring rates: transcription regulatory, phosphorylation regulatory, genetic interaction, miRNA regulatory, protein interaction, and metabolic pathway network, from fast to slow. This ordering was found in all comparisons we did of matched networks between organisms. To gain further intuition on network rewiring, we compared our observed rewirings with those obtained from simulation. We also investigated how readily our formalism could be mapped to other network contexts; in particular, we showed how it could be applied to analyze changes in a range of "commonplace" networks such as family trees, co-authorships and linux-kernel function dependencies.

  12. Using blood cytokine measures to define high inflammatory biotype of schizophrenia and schizoaffective disorder.

    Science.gov (United States)

    Boerrigter, Danny; Weickert, Thomas W; Lenroot, Rhoshel; O'Donnell, Maryanne; Galletly, Cherrie; Liu, Dennis; Burgess, Martin; Cadiz, Roxanne; Jacomb, Isabella; Catts, Vibeke S; Fillman, Stu G; Weickert, Cynthia Shannon

    2017-09-18

    Increases in pro-inflammatory cytokines are found in the brain and blood of people with schizophrenia. However, increased cytokines are not evident in all people with schizophrenia, but are found in a subset. The cytokine changes that best define this subset, termed the "elevated inflammatory biotype", are still being identified. Using quantitative RT-PCR, we measured five cytokine mRNAs (IL-1β, IL-2 IL-6, IL-8 and IL-18) from peripheral blood of healthy controls and of people with schizophrenia or schizoaffective disorder (n = 165). We used a cluster analysis of the transcript levels to define those with low and those with elevated levels of cytokine expression. From the same cohort, eight cytokine proteins (IL-1β, IL-2, IL-6, IL-8, IL-10, IL-12, IFNγ and TNFα) were measured in serum and plasma using a Luminex Magpix-based assay. We compared peripheral mRNA and protein levels across diagnostic groups and between those with low and elevated levels of cytokine expression according to our transcription-based cluster analysis. We found an overall decrease in the anti-inflammatory IL-2 mRNA (p = 0.006) and an increase in three serum cytokines, IL-6 (p = 0.010), IL-8 (p = 0.024) and TNFα (p schizophrenia compared to healthy controls. A greater percentage of people with schizophrenia (48%) were categorised into the elevated inflammatory biotype compared to healthy controls (33%). The magnitude of increase in IL-1β, IL-6, IL-8 and IL-10 mRNAs in people in the elevated inflammation biotype ranged from 100 to 220% of those in the non-elevated inflammatory biotype and was comparable between control and schizophrenia groups. Blood cytokine protein levels did not correlate with cytokine mRNA levels, and plasma levels of only two cytokines distinguished the elevated and low inflammatory biotypes, with IL-1β significantly increased in the elevated cytokine control group and IL-8 significantly increased in the elevated cytokine schizophrenia group. Our results

  13. Centrality measures in temporal networks with time series analysis

    Science.gov (United States)

    Huang, Qiangjuan; Zhao, Chengli; Zhang, Xue; Wang, Xiaojie; Yi, Dongyun

    2017-05-01

    The study of identifying important nodes in networks has a wide application in different fields. However, the current researches are mostly based on static or aggregated networks. Recently, the increasing attention to networks with time-varying structure promotes the study of node centrality in temporal networks. In this paper, we define a supra-evolution matrix to depict the temporal network structure. With using of the time series analysis, the relationships between different time layers can be learned automatically. Based on the special form of the supra-evolution matrix, the eigenvector centrality calculating problem is turned into the calculation of eigenvectors of several low-dimensional matrices through iteration, which effectively reduces the computational complexity. Experiments are carried out on two real-world temporal networks, Enron email communication network and DBLP co-authorship network, the results of which show that our method is more efficient at discovering the important nodes than the common aggregating method.

  14. Measured and perceived environmental characteristics are related to accelerometer defined physical activity in older adults

    Directory of Open Access Journals (Sweden)

    Strath Scott J

    2012-04-01

    Full Text Available Abstract Background Few studies have investigated both the self-perceived and measured environment with objectively determined physical activity in older adults. Accordingly, the aim of this study was to examine measured and perceived environmental associations with physical activity of older adults residing across different neighborhood types. Methods One-hundred and forty-eight older individuals, mean age 64.3 ± 8.4, were randomly recruited from one of four neighborhoods that were pre-determined as either having high- or low walkable characteristics. Individual residences were geocoded and 200 m network buffers established. Both objective environment audit, and self-perceived environmental measures were collected, in conjunction with accelerometer derived physical activity behavior. Using both perceived and objective environment data, analysis consisted of a macro-level comparison of physical activity levels across neighborhood, and a micro-level analysis of individual environmental predictors of physical activity levels. Results Individuals residing in high-walkable neighborhoods on average engaged in 11 min of moderate to vigorous physical activity per day more than individuals residing in low-walkable neighborhoods. Both measured access to non-residential destinations (b = .11, p p = .031 were significant predictors of time spent in moderate to vigorous physical activity. Other environmental variables significantly predicting components of physical activity behavior included presence of measured neighborhood crime signage (b = .4785, p = .031, measured street safety (b = 26.8, p = .006, and perceived neighborhood satisfaction (b = .5.8, p = .003. Conclusions Older adult residents who live in high-walkable neighborhoods, who have easy and close access to nonresidential destinations, have lower social dysfunction pertinent to crime, and generally perceive the neighborhood to a higher overall satisfaction are likely to engage in higher levels

  15. Defining Primary Care Shortage Areas: Do GIS-based Measures Yield Different Results?

    Science.gov (United States)

    Daly, Michael R; Mellor, Jennifer M; Millones, Marco

    2018-02-12

    To examine whether geographic information systems (GIS)-based physician-to-population ratios (PPRs) yield determinations of geographic primary care shortage areas that differ from those based on bounded-area PPRs like those used in the Health Professional Shortage Area (HPSA) designation process. We used geocoded data on primary care physician (PCP) locations and census block population counts from 1 US state to construct 2 shortage area indicators. The first is a bounded-area shortage indicator defined without GIS methods; the second is a GIS-based measure that measures the populations' spatial proximity to PCP locations. We examined agreement and disagreement between bounded shortage areas and GIS-based shortage areas. Bounded shortage area indicators and GIS-based shortage area indicators agree for the census blocks where the vast majority of our study populations reside. Specifically, 95% and 98% of the populations in our full and urban samples, respectively, reside in census blocks where the 2 indicators agree. Although agreement is generally high in rural areas (ie, 87% of the rural population reside in census blocks where the 2 indicators agree), agreement is significantly lower compared to urban areas. One source of disagreement suggests that bounded-area measures may "overlook" some shortages in rural areas; however, other aspects of the HPSA designation process likely mitigate this concern. Another source of disagreement arises from the border-crossing problem, and it is more prevalent. The GIS-based PPRs we employed would yield shortage area determinations that are similar to those based on bounded-area PPRs defined for Primary Care Service Areas. Disagreement rates were lower than previous studies have found. © 2018 National Rural Health Association.

  16. Improving inferior vena cava filter retrieval rates with the define, measure, analyze, improve, control methodology.

    Science.gov (United States)

    Sutphin, Patrick D; Reis, Stephen P; McKune, Angie; Ravanzo, Maria; Kalva, Sanjeeva P; Pillai, Anil K

    2015-04-01

    To design a sustainable process to improve optional inferior vena cava (IVC) filter retrieval rates based on the Define, Measure, Analyze, Improve, Control (DMAIC) methodology of the Six Sigma process improvement paradigm. DMAIC, an acronym for Define, Measure, Analyze, Improve, and Control, was employed to design and implement a quality improvement project to increase IVC filter retrieval rates at a tertiary academic hospital. Retrievable IVC filters were placed in 139 patients over a 2-year period. The baseline IVC filter retrieval rate (n = 51) was reviewed through a retrospective analysis, and two strategies were devised to improve the filter retrieval rate: (a) mailing of letters to clinicians and patients for patients who had filters placed within 8 months of implementation of the project (n = 43) and (b) a prospective automated scheduling of a clinic visit at 4 weeks after filter placement for all new patients (n = 45). The effectiveness of these strategies was assessed by measuring the filter retrieval rates and estimated increase in revenue to interventional radiology. IVC filter retrieval rates increased from a baseline of 8% to 40% with the mailing of letters and to 52% with the automated scheduling of a clinic visit 4 weeks after IVC filter placement. The estimated revenue per 100 IVC filters placed increased from $2,249 to $10,518 with the mailing of letters and to $17,022 with the automated scheduling of a clinic visit. Using the DMAIC methodology, a simple and sustainable quality improvement intervention was devised that markedly improved IVC filter retrieval rates in eligible patients. Copyright © 2015 SIR. Published by Elsevier Inc. All rights reserved.

  17. State-of-the-art on Virtualization and Software Defined Networking for Efficient Resource Allocation on Multi-tenant 5G Networks

    Directory of Open Access Journals (Sweden)

    Tsirakis Christos

    2017-01-01

    Full Text Available Global data traffic explosion is expected to set stringent requirements for next generation networks in the next decades. Besides, very low latencies will have to be guaranteed for enabling new delay critical services. However, current Software Defined Networking (SDN solutions have limitations in terms of separating both data and control planes among tenants/operators, and the capability to adapt to new or changing requirements. Moreover, some virtualization schemes do not ensure isolation of resources and do not guarantee bandwidth across the entities. While some others fail to provide flexibility to the slices to customize the resource allocation across the users. Therefore, novel SDN and virtualization techniques should be implemented to realize the upcoming 5G network that will facilitate at least efficient resource allocation and multi-tenancy among the plethora of different requirements.

  18. Are Self-report Measures Able to Define Individuals as Physically Active or Inactive?

    Science.gov (United States)

    Steene-Johannessen, Jostein; Anderssen, Sigmund A; van der Ploeg, Hidde P; Hendriksen, Ingrid J M; Donnelly, Alan E; Brage, Søren; Ekelund, Ulf

    2016-02-01

    Assess the agreement between commonly used self-report methods compared with objectively measured physical activity (PA) in defining the prevalence of individuals compliant with PA recommendations. Time spent in moderate and vigorous PA (MVPA) was measured at two time points in 1713 healthy individuals from nine European countries using individually calibrated combined heart rate and movement sensing. Participants also completed the Recent Physical Activity Questionnaire (RPAQ), short form of the International Physical Activity Questionnaire (IPAQ), and short European Prospective Investigation into Cancer and Nutrition Physical Activity Questionnaire (EPIC-PAQ). Individuals were categorized as active (e.g., reporting ≥150 min of MVPA per week) or inactive, based on the information derived from the different measures. Sensitivity and specificity analyses and Kappa statistics were performed to evaluate the ability of the three PA questionnaires to correctly categorize individuals as active or inactive. Prevalence estimates of being sufficiently active varied significantly (P for all PAQ 39.9% [95% CI, 37.5-42.1] and objective measure 48.5% [95% CI, 41.6-50.9]. All self-report methods showed low or moderate sensitivity (IPAQ 20.0%, RPAQ 18.7%, and EPIC-PAQ 69.8%) to correctly classify inactive people and the agreement between objective and self-reported PA was low (ĸ = 0.07 [95% CI, 0.02-0.12], 0.12 [95% CI, 0.06-0.18], and 0.19 [95% CI, 0.13-0.24] for IPAQ, RPAQ, and EPIC-PAQ, respectively). The modest agreement between self-reported and objectively measured PA suggests that population levels of PA derived from self-report should be interpreted cautiously. Implementation of objective measures in large-scale cohort studies and surveillance systems is recommended.

  19. Performance evaluation of data center service localization based on virtual resource migration in software defined elastic optical network.

    Science.gov (United States)

    Yang, Hui; Zhang, Jie; Ji, Yuefeng; Tan, Yuanlong; Lin, Yi; Han, Jianrui; Lee, Young

    2015-09-07

    Data center interconnection with elastic optical network is a promising scenario to meet the high burstiness and high-bandwidth requirements of data center services. In our previous work, we implemented cross stratum optimization of optical network and application stratums resources that allows to accommodate data center services. In view of this, this study extends the data center resources to user side to enhance the end-to-end quality of service. We propose a novel data center service localization (DCSL) architecture based on virtual resource migration in software defined elastic data center optical network. A migration evaluation scheme (MES) is introduced for DCSL based on the proposed architecture. The DCSL can enhance the responsiveness to the dynamic end-to-end data center demands, and effectively reduce the blocking probability to globally optimize optical network and application resources. The overall feasibility and efficiency of the proposed architecture are experimentally verified on the control plane of our OpenFlow-based enhanced SDN testbed. The performance of MES scheme under heavy traffic load scenario is also quantitatively evaluated based on DCSL architecture in terms of path blocking probability, provisioning latency and resource utilization, compared with other provisioning scheme.

  20. On Measuring the Complexity of Networks: Kolmogorov Complexity versus Entropy

    Directory of Open Access Journals (Sweden)

    Mikołaj Morzy

    2017-01-01

    Full Text Available One of the most popular methods of estimating the complexity of networks is to measure the entropy of network invariants, such as adjacency matrices or degree sequences. Unfortunately, entropy and all entropy-based information-theoretic measures have several vulnerabilities. These measures neither are independent of a particular representation of the network nor can capture the properties of the generative process, which produces the network. Instead, we advocate the use of the algorithmic entropy as the basis for complexity definition for networks. Algorithmic entropy (also known as Kolmogorov complexity or K-complexity for short evaluates the complexity of the description required for a lossless recreation of the network. This measure is not affected by a particular choice of network features and it does not depend on the method of network representation. We perform experiments on Shannon entropy and K-complexity for gradually evolving networks. The results of these experiments point to K-complexity as the more robust and reliable measure of network complexity. The original contribution of the paper includes the introduction of several new entropy-deceiving networks and the empirical comparison of entropy and K-complexity as fundamental quantities for constructing complexity measures for networks.

  1. Using Bayesian network and AHP method as a marketing approach tools in defining tourists’ preferences

    Directory of Open Access Journals (Sweden)

    Nataša Papić-Blagojević

    2012-04-01

    Full Text Available Marketing approach is associated to market conditions and achieving long term profitability of a company by satisfying consumers’ needs. This approach in tourism does not have to be related only to promoting one touristic destination, but is associated to relation between travel agency and its clients too. It considers that travel agencies adjust their offers to their clients’ needs. In that sense, it is important to analyze the behavior of tourists in the earlier periods with consideration of their preferences. Using Bayesian network, it could be graphically displayed the connection between tourists who have similar taste and relationships between them. On the other hand, the analytic hierarchy process (AHP is used to rank tourist attractions, with also relying on past experience. In this paper we examine possible applications of these two models in tourism in Serbia. The example is hypothetical, but it will serve as a base for future research. Three types of tourism are chosen as a representative in Vojvodina: Cultural, Rural and Business tourism, because they are the bright spot of touristic development in this area. Applied on these forms, analytic hierarchy process has shown its strength in predicting tourists’ preferences.

  2. Measuring the democratic anchorage of governance networks

    DEFF Research Database (Denmark)

    Fotel, Trine; Sørensen, Eva; Torfing, Jacob

    There has been a growing debate about the democratic problems and potentials of governance networks among political scientists and public managers. While some claim that governance networks tend to undermine democracy, others argue that they have the potential to improve and strengthen democracy....... This debate is found wanting in two respects. First of all, there has been far too little discussion about what democracy means in relation to pluricentric governance networks. Second, the current debate builds on the assumption that it is possible to give a clear-cut answer to the question of the democratic...... problems and merits of governance networks. This assumption is highly questionable, and prevents a more nuanced assessment of the democratic performance of governance networks. As such, it diverts the focus of attention away from the fact that governance networks may be democratic in some respects...

  3. Measuring Asymmetry in Insect-Plant Networks

    Energy Technology Data Exchange (ETDEWEB)

    Cruz, Claudia P T [Programa de Pos-Graduacao em Fisica, Universidade Federal do Rio Grande do Norte, UFRN - Campus Universitario, Lagoa Nova, CEP 59078 972, Natal, RN (Brazil); De Almeida, Adriana M [Departamento de Botanica, Ecologia e Zoologia, Centro de Biociencias, Universidade Federal do Rio Grande do Norte, UFRN - Campus Universitario, Lagoa Nova, CEP 59078 972, Natal, RN (Brazil); Corso, Gilberto, E-mail: claudia@dfte.ufrn.br, E-mail: adrianam@ufrn.br, E-mail: corso@cb.ufrn.br [Departamento de Biofisica e Farmacologia, Centro de Biociencias, Universidade Federal do Rio Grande do Norte, UFRN - Campus Universitario, Lagoa Nova, CEP 59078 972, Natal, RN (Brazil)

    2011-03-01

    In this work we focus on interaction networks between insects and plants and in the characterization of insect plant asymmetry, an important issue in coevolution and evolutionary biology. We analyze in particular the asymmetry in the interaction matrix of animals (herbivorous insects) and plants (food resource for the insects). Instead of driving our attention to the interaction matrix itself we derive two networks associated to the bipartite network: the animal network, D{sub 1}, and the plant network, D{sub 2}. These networks are constructed according to the following recipe: two animal species are linked once if they interact with the same plant. In a similar way, in the plant network, two plants are linked if they interact with the same animal. To explore the asymmetry between D{sub 2} and D{sub 1} we test for a set of 23 networks from the ecologic literature networks: the difference in size, {Delta}L, clustering coefficient difference, {Delta}C, and mean connectivity difference, {Delta}. We used a nonparametric statistical test to check the differences in {Delta}L, {Delta}C and {Delta}. Our results indicate that {Delta}L and {Delta} show a significative asymmetry.

  4. Defining and Measuring Safety Climate: A Review of the Construction Industry Literature.

    Science.gov (United States)

    Schwatka, Natalie V; Hecker, Steven; Goldenhar, Linda M

    2016-06-01

    Safety climate measurements can be used to proactively assess an organization's effectiveness in identifying and remediating work-related hazards, thereby reducing or preventing work-related ill health and injury. This review article focuses on construction-specific articles that developed and/or measured safety climate, assessed safety climate's relationship with other safety and health performance indicators, and/or used safety climate measures to evaluate interventions targeting one or more indicators of safety climate. Fifty-six articles met our inclusion criteria, 80% of which were published after 2008. Our findings demonstrate that researchers commonly defined safety climate as perception based, but the object of those perceptions varies widely. Within the wide range of indicators used to measure safety climate, safety policies, procedures, and practices were the most common, followed by general management commitment to safety. The most frequently used indicators should and do reflect that the prevention of work-related ill health and injury depends on both organizational and employee actions. Safety climate scores were commonly compared between groups (e.g. management and workers, different trades), and often correlated with subjective measures of safety behavior rather than measures of ill health or objective safety and health outcomes. Despite the observed limitations of current research, safety climate has been promised as a useful feature of research and practice activities to prevent work-related ill health and injury. Safety climate survey data can reveal gaps between management and employee perceptions, or between espoused and enacted policies, and trigger communication and action to narrow those gaps. The validation of safety climate with safety and health performance data offers the potential for using safety climate measures as a leading indicator of performance. We discuss these findings in relation to the related concept of safety culture and

  5. An assessment of available measures to reduce traction energy use in railway networks

    International Nuclear Information System (INIS)

    Douglas, Heather; Roberts, Clive; Hillmansen, Stuart; Schmid, Felix

    2015-01-01

    Highlights: • Railway networks are defined in terms of their distinguishing features. • Current energy saving measures are reviewed and categorised by the energy use they target. • The achievable energy savings of different measures are compared dependent on the network type. • The success of a measure depends on the characteristics of the network, vehicle and service. • Measures should be evaluated at system level due to interdependencies. - Abstract: Rail is becoming an increasingly popular choice to satisfy transportation demands locally, nationally and internationally, due to its inherent efficiency and high capacity. Despite this, operators are facing pressure to reduce rail energy consumption to meet efficiency targets, whilst still maintaining service quality and managing increased demand. A number of individual measures have been proposed to reduce energy in the rail sector, often showing good results on specific case studies. It is generally agreed that the attainable savings of a given measure change dependant on the route, vehicle and service characteristics. However, there is little information in the literature specifically regarding which measures are most suitable for given network types, or how they interact. This paper therefore aims to begin evaluating the available measures in terms of their suitability for different systems. Firstly, networks are defined in terms of their distinguishing features. As traction accounts for the majority of all energy use in the rail sector, the traction flow through a vehicle is considered as the starting point for an evaluation of measures. Current technologies and procedures are reviewed and categorised based on which area of traction use they target. Thought is given to the factors that affect implementation and the networks where they are applied. A key output of this paper is a comparison of the achievable energy savings of different measures dependent on the network type. It is hoped that this will

  6. Network cohesion

    OpenAIRE

    Cavalcanti, Tiago Vanderlei; Giannitsarou, Chrysi; Johnson, CR

    2017-01-01

    We define a measure of network cohesion and show how it arises naturally in a broad class of dynamic models of endogenous perpetual growth with network externalities. Via a standard growth model, we show why network cohesion is crucial for conditional convergence and explain that as cohesion increases, convergence is faster. We prove properties of network cohesion and define a network aggregator that preserves network cohesion.

  7. Precautionary measures to prevent damage, as defined in the Atomic Energy Law

    International Nuclear Information System (INIS)

    Marburger, P.

    1983-01-01

    The requirement to take every 'precaution which is necessary in the light of existing scientific knowledge and technology to prevent damage' (section 7, sub-section (2), no. 3 Atomic Energy Act) is not restricted to conventional (preventive) measures but is to be understood as a duty to actively provide for appropriate protection from conceivable damage. Below the level of legally binding laws and regulations, there is the level of scientific-technical codes and standards, which are of great significance to the licensing procedure under atomic energy law. As these codes and standards do not form part of the law but nevertheless represent the essence of scientific knowledge needed to fulfill the duty defined by the law, they are gaining full impact only through the licensing procedure, thus being transformed into concrete legal requirements. Hence one can say that the legal situation in atomic energy law relating to the licensing requirements as laid down in section 7, sub-section (2), no. 3 is presently characterised by a regulatory deficit. This regulatory deficit cannot be overcome by the means and tools offered by the current law. One possibility to fill the gap is to give a legally binding status to the safety guides defined by the deterministic safety concept, by listing the conceivable accidents to be mastered. This recommendable procedure could lead to an ordinance on the safety of nuclear installations. Such an ordinance could be kept abreast with technical progress and scientific knowledge by creating a referring legal instrument, pointing to, e.g., the KTA Safety Guide. (orig./HSCH) [de

  8. A measure of the denseness of a phylogenetic network. [by sequenced proteins from extant species

    Science.gov (United States)

    Holmquist, R.

    1978-01-01

    An objective measure of phylogenetic denseness is developed to examine various phylogenetic criteria: alpha- and beta-hemoglobin, myoglobin, cytochrome c, and the parvalbumin family. Attention is given to the number of nucleotide replacements separating homologous sequences, and to the topology of the network (in other words, to the qualitative nature of the network as defined by how closely the studied species are related). Applications include quantitative comparisons of species origin, relation, and rates of evolution.

  9. Network module detection: Affinity search technique with the multi-node topological overlap measure.

    Science.gov (United States)

    Li, Ai; Horvath, Steve

    2009-07-20

    Many clustering procedures only allow the user to input a pairwise dissimilarity or distance measure between objects. We propose a clustering method that can input a multi-point dissimilarity measure d(i1, i2, ..., iP) where the number of points P can be larger than 2. The work is motivated by gene network analysis where clusters correspond to modules of highly interconnected nodes. Here, we define modules as clusters of network nodes with high multi-node topological overlap. The topological overlap measure is a robust measure of interconnectedness which is based on shared network neighbors. In previous work, we have shown that the multi-node topological overlap measure yields biologically meaningful results when used as input of network neighborhood analysis. We adapt network neighborhood analysis for the use of module detection. We propose the Module Affinity Search Technique (MAST), which is a generalized version of the Cluster Affinity Search Technique (CAST). MAST can accommodate a multi-node dissimilarity measure. Clusters grow around user-defined or automatically chosen seeds (e.g. hub nodes). We propose both local and global cluster growth stopping rules. We use several simulations and a gene co-expression network application to argue that the MAST approach leads to biologically meaningful results. We compare MAST with hierarchical clustering and partitioning around medoid clustering. Our flexible module detection method is implemented in the MTOM software which can be downloaded from the following webpage: http://www.genetics.ucla.edu/labs/horvath/MTOM/

  10. Measuring symmetry, asymmetry and randomness in neural network connectivity.

    Directory of Open Access Journals (Sweden)

    Umberto Esposito

    Full Text Available Cognitive functions are stored in the connectome, the wiring diagram of the brain, which exhibits non-random features, so-called motifs. In this work, we focus on bidirectional, symmetric motifs, i.e. two neurons that project to each other via connections of equal strength, and unidirectional, non-symmetric motifs, i.e. within a pair of neurons only one neuron projects to the other. We hypothesise that such motifs have been shaped via activity dependent synaptic plasticity processes. As a consequence, learning moves the distribution of the synaptic connections away from randomness. Our aim is to provide a global, macroscopic, single parameter characterisation of the statistical occurrence of bidirectional and unidirectional motifs. To this end we define a symmetry measure that does not require any a priori thresholding of the weights or knowledge of their maximal value. We calculate its mean and variance for random uniform or Gaussian distributions, which allows us to introduce a confidence measure of how significantly symmetric or asymmetric a specific configuration is, i.e. how likely it is that the configuration is the result of chance. We demonstrate the discriminatory power of our symmetry measure by inspecting the eigenvalues of different types of connectivity matrices. We show that a Gaussian weight distribution biases the connectivity motifs to more symmetric configurations than a uniform distribution and that introducing a random synaptic pruning, mimicking developmental regulation in synaptogenesis, biases the connectivity motifs to more asymmetric configurations, regardless of the distribution. We expect that our work will benefit the computational modelling community, by providing a systematic way to characterise symmetry and asymmetry in network structures. Further, our symmetry measure will be of use to electrophysiologists that investigate symmetry of network connectivity.

  11. Measuring symmetry, asymmetry and randomness in neural network connectivity.

    Science.gov (United States)

    Esposito, Umberto; Giugliano, Michele; van Rossum, Mark; Vasilaki, Eleni

    2014-01-01

    Cognitive functions are stored in the connectome, the wiring diagram of the brain, which exhibits non-random features, so-called motifs. In this work, we focus on bidirectional, symmetric motifs, i.e. two neurons that project to each other via connections of equal strength, and unidirectional, non-symmetric motifs, i.e. within a pair of neurons only one neuron projects to the other. We hypothesise that such motifs have been shaped via activity dependent synaptic plasticity processes. As a consequence, learning moves the distribution of the synaptic connections away from randomness. Our aim is to provide a global, macroscopic, single parameter characterisation of the statistical occurrence of bidirectional and unidirectional motifs. To this end we define a symmetry measure that does not require any a priori thresholding of the weights or knowledge of their maximal value. We calculate its mean and variance for random uniform or Gaussian distributions, which allows us to introduce a confidence measure of how significantly symmetric or asymmetric a specific configuration is, i.e. how likely it is that the configuration is the result of chance. We demonstrate the discriminatory power of our symmetry measure by inspecting the eigenvalues of different types of connectivity matrices. We show that a Gaussian weight distribution biases the connectivity motifs to more symmetric configurations than a uniform distribution and that introducing a random synaptic pruning, mimicking developmental regulation in synaptogenesis, biases the connectivity motifs to more asymmetric configurations, regardless of the distribution. We expect that our work will benefit the computational modelling community, by providing a systematic way to characterise symmetry and asymmetry in network structures. Further, our symmetry measure will be of use to electrophysiologists that investigate symmetry of network connectivity.

  12. Measuring solar reflectance - Part I: Defining a metric that accurately predicts solar heat gain

    Energy Technology Data Exchange (ETDEWEB)

    Levinson, Ronnen; Akbari, Hashem; Berdahl, Paul [Heat Island Group, Environmental Energy Technologies Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States)

    2010-09-15

    Solar reflectance can vary with the spectral and angular distributions of incident sunlight, which in turn depend on surface orientation, solar position and atmospheric conditions. A widely used solar reflectance metric based on the ASTM Standard E891 beam-normal solar spectral irradiance underestimates the solar heat gain of a spectrally selective ''cool colored'' surface because this irradiance contains a greater fraction of near-infrared light than typically found in ordinary (unconcentrated) global sunlight. At mainland US latitudes, this metric R{sub E891BN} can underestimate the annual peak solar heat gain of a typical roof or pavement (slope {<=} 5:12 [23 ]) by as much as 89 W m{sup -2}, and underestimate its peak surface temperature by up to 5 K. Using R{sub E891BN} to characterize roofs in a building energy simulation can exaggerate the economic value N of annual cool roof net energy savings by as much as 23%. We define clear sky air mass one global horizontal (''AM1GH'') solar reflectance R{sub g,0}, a simple and easily measured property that more accurately predicts solar heat gain. R{sub g,0} predicts the annual peak solar heat gain of a roof or pavement to within 2 W m{sup -2}, and overestimates N by no more than 3%. R{sub g,0} is well suited to rating the solar reflectances of roofs, pavements and walls. We show in Part II that R{sub g,0} can be easily and accurately measured with a pyranometer, a solar spectrophotometer or version 6 of the Solar Spectrum Reflectometer. (author)

  13. Measuring solar reflectance Part I: Defining a metric that accurately predicts solar heat gain

    Energy Technology Data Exchange (ETDEWEB)

    Levinson, Ronnen; Akbari, Hashem; Berdahl, Paul

    2010-05-14

    Solar reflectance can vary with the spectral and angular distributions of incident sunlight, which in turn depend on surface orientation, solar position and atmospheric conditions. A widely used solar reflectance metric based on the ASTM Standard E891 beam-normal solar spectral irradiance underestimates the solar heat gain of a spectrally selective 'cool colored' surface because this irradiance contains a greater fraction of near-infrared light than typically found in ordinary (unconcentrated) global sunlight. At mainland U.S. latitudes, this metric RE891BN can underestimate the annual peak solar heat gain of a typical roof or pavement (slope {le} 5:12 [23{sup o}]) by as much as 89 W m{sup -2}, and underestimate its peak surface temperature by up to 5 K. Using R{sub E891BN} to characterize roofs in a building energy simulation can exaggerate the economic value N of annual cool-roof net energy savings by as much as 23%. We define clear-sky air mass one global horizontal ('AM1GH') solar reflectance R{sub g,0}, a simple and easily measured property that more accurately predicts solar heat gain. R{sub g,0} predicts the annual peak solar heat gain of a roof or pavement to within 2 W m{sup -2}, and overestimates N by no more than 3%. R{sub g,0} is well suited to rating the solar reflectances of roofs, pavements and walls. We show in Part II that R{sub g,0} can be easily and accurately measured with a pyranometer, a solar spectrophotometer or version 6 of the Solar Spectrum Reflectometer.

  14. Consensus statement on defining and measuring negative effects of Internet interventions

    Directory of Open Access Journals (Sweden)

    Alexander Rozental

    2014-03-01

    Full Text Available Internet interventions have great potential for alleviating emotional distress, promoting mental health, and enhancing well-being. Numerous clinical trials have demonstrated their efficacy for a number of psychiatric conditions, and interventions delivered via the Internet will likely become a common alternative to face-to-face treatment. Meanwhile, research has paid little attention to the negative effects associated with treatment, warranting further investigation of the possibility that some patients might deteriorate or encounter adverse events despite receiving best available care. Evidence from research of face-to-face treatment suggests that negative effects afflict 5–10% of all patients undergoing treatment in terms of deterioration. However, there is currently a lack of consensus on how to define and measure negative effects in psychotherapy research in general, leaving researchers without practical guidelines for monitoring and reporting negative effects in clinical trials. The current paper therefore seeks to provide recommendations that could promote the study of negative effects in Internet interventions with the aim of increasing the knowledge of its occurrence and characteristics. Ten leading experts in the field of Internet interventions were invited to participate and share their perspective on how to explore negative effects, using the Delphi technique to facilitate a dialog and reach an agreement. The authors discuss the importance of conducting research on negative effects in order to further the understanding of its incidence and different features. Suggestions on how to classify and measure negative effects in Internet interventions are proposed, involving methods from both quantitative and qualitative research. Potential mechanisms underlying negative effects are also discussed, differentiating common factors shared with face-to-face treatments from those unique to treatments delivered via the Internet. The authors

  15. Representative Delay Measurements (RDM: Facing the Challenge of Modern Networks

    Directory of Open Access Journals (Sweden)

    Joachim Fabini

    2015-02-01

    Full Text Available Network access technologies have evolved significantly in the last years. They deploy novel mechanisms like reactive capacity allocation and time-slotted operation to optimize overall network capacity. From a single node's perspective, such optimizations decrease network determinism and measurement repeatability. Evolving application fields like machine to machine (M2M communications or real-time gaming often have strict real-time requirements to operate correctly. Highly accurate delay measurements are necessary to monitor network compliance with application demands or to detect deviations of normal network behavior, which may be caused by network failures, misconfigurations or attacks. This paper analyzes factors that challenge active delay measurements in modern networks. It introduces the Representative Delay Measurement tool (RDM that addresses these factors and proposes solutions that conform to requirements of the recently published RFC7312. Delay measurement results acquired using RDM in live networks confirm that advanced measurement methods can significantly improve the quality of measurement samples by isolating systematic network behavior. The resulting high-quality samples are one prerequisite for accurate statistics that support proper operation of subsequent algorithms and applications.

  16. National network of environment radioactivity measurements. Press kit

    International Nuclear Information System (INIS)

    2010-01-01

    This document first presents the objectives, challenges, context, operation and actors of the French national network of environment radioactivity measurements. It discusses the reasons for these measurements, the way they are performed, who perform them and how they are transmitted to the national network. It describes the quality policy for these measurements, and how this network is at the service of authorities, experts and population. It outlines the originality of the French approach within the European Union, and how this network takes the population expectations and their evolution into account

  17. Exploiting the Vulnerability of Flow Table Overflow in Software-Defined Network: Attack Model, Evaluation, and Defense

    Directory of Open Access Journals (Sweden)

    Yadong Zhou

    2018-01-01

    Full Text Available As the most competitive solution for next-generation network, SDN and its dominant implementation OpenFlow are attracting more and more interests. But besides convenience and flexibility, SDN/OpenFlow also introduces new kinds of limitations and security issues. Of these limitations, the most obvious and maybe the most neglected one is the flow table capacity of SDN/OpenFlow switches. In this paper, we proposed a novel inference attack targeting at SDN/OpenFlow network, which is motivated by the limited flow table capacities of SDN/OpenFlow switches and the following measurable network performance decrease resulting from frequent interactions between data and control plane when the flow table is full. To the best of our knowledge, this is the first proposed inference attack model of this kind for SDN/OpenFlow. We implemented an inference attack framework according to our model and examined its efficiency and accuracy. The evaluation results demonstrate that our framework can infer the network parameters (flow table capacity and usage with an accuracy of 80% or higher. We also proposed two possible defense strategies for the discovered vulnerability, including routing aggregation algorithm and multilevel flow table architecture. These findings give us a deeper understanding of SDN/OpenFlow limitations and serve as guidelines to future improvements of SDN/OpenFlow.

  18. Perimetric measurements with flicker-defined form stimulation in comparison with conventional perimetry and retinal nerve fiber measurements.

    Science.gov (United States)

    Horn, Folkert K; Tornow, Ralf P; Jünemann, Anselm G; Laemmer, Robert; Kremers, Jan

    2014-04-11

    We compared the results of flicker-defined form (FDF) perimetry with standard automated perimetry (SAP) and retinal nerve fiber layer (RNFL) thickness measurements using spectral domain optical coherence tomography (OCT). A total of 64 healthy subjects, 45 ocular hypertensive patients, and 97 "early" open-angle glaucoma (OAG) patients participated in this study. Definition of glaucoma was based exclusively on glaucomatous optic disc appearance. All subjects underwent FDF perimetry, SAP, and peripapillary measurements of the RNFL thickness. The FDF perimetry and SAP were performed at identical test locations (G1 protocol). Exclusion criteria were subjects younger than 34 years, SAP mean defect (SAP MD) > 5 dB, eye diseases other than glaucoma, or nonreliable FDF measurements. The correlations between the perimetric data on one hand and RNFL thicknesses on the other hand were analyzed statistically. The age-corrected sensitivity values and the local results from the controls were used to determine FDF mean defect (FDF MD). The FDF perimetry and SAP showed high concordance in this cohort of experienced patients (MD values, R = -0.69, P < 0.001). Of a total of 42 OAG patients with abnormal SAP MD, 38 also displayed abnormal FDF MD. However, FDF MD was abnormal in 28 of 55 OAG patients with normal SAP MD. The FDF MD was significantly (R = -0.61, P < 0.001) correlated with RNFL thickness with a (nonsignificantly) larger correlation coefficient than conventional SAP MD (R = -0.48, P < 0.001). The FDF perimetry is able to uncover functional changes concurrent with the changes in RNFL thickness. The FDF perimetry may be an efficient functional test to detect early glaucomatous nerve atrophy. (ClinicalTrials.gov number, NCT00494923.).

  19. Defining and Measuring the Affordability of New Medicines: A Systematic Review.

    Science.gov (United States)

    Antoñanzas, Fernando; Terkola, Robert; Overton, Paul M; Shalet, Natalie; Postma, Maarten

    2017-08-01

    In many healthcare systems, affordability concerns can lead to restrictions on the use of expensive efficacious therapies. However, there does not appear to be any consensus as to the terminology used to describe affordability, or the thresholds used to determine whether new drugs are affordable. The aim of this systematic review was to investigate how affordability is defined and measured in healthcare. MEDLINE, EMBASE and EconLit databases (2005-July 2016) were searched using terms covering affordability and budget impact, combined with definitions, thresholds and restrictions, to identify articles describing a definition of affordability with respect to new medicines. Additional definitions were identified through citation searching, and through manual searches of European health technology assessment body websites. In total, 27 definitions were included in the review. Of these, five definitions described affordability in terms of the value of a product; seven considered affordability within the context of healthcare system budgets; and 15 addressed whether products are affordable in a given country based on economic factors. However, there was little in the literature to indicate that the price of medicines is considered alongside both their value to individual patients and their budget impact at a population level. Current methods of assessing affordability in healthcare may be limited by their focus on budget impact. A more effective approach may involve a broader perspective than is currently described in the literature, to consider the long-term benefits of a therapy and cost savings elsewhere in the healthcare system, as well as cooperation between healthcare payers and the pharmaceutical industry to develop financing models that support sustainability as well as innovation.

  20. Monodisperse measurement of the biotin-streptavidin interaction strength in a well-defined pulling geometry.

    Directory of Open Access Journals (Sweden)

    Steffen M Sedlak

    Full Text Available The widely used interaction of the homotetramer streptavidin with the small molecule biotin has been intensively studied by force spectroscopy and has become a model system for receptor ligand interaction. However, streptavidin's tetravalency results in diverse force propagation pathways through the different binding interfaces. This multiplicity gives rise to polydisperse force spectroscopy data. Here, we present an engineered monovalent streptavidin tetramer with a single cysteine in its functional subunit that allows for site-specific immobilization of the molecule, orthogonal to biotin binding. Functionality of streptavidin and its binding properties for biotin remain unaffected. We thus created a stable and reliable molecular anchor with a unique high-affinity binding site for biotinylated molecules or nanoparticles, which we expect to be useful for many single-molecule applications. To characterize the mechanical properties of the bond between biotin and our monovalent streptavidin, we performed force spectroscopy experiments using an atomic force microscope. We were able to conduct measurements at the single-molecule level with 1:1-stoichiometry and a well-defined geometry, in which force exclusively propagates through a single subunit of the streptavidin tetramer. For different force loading rates, we obtained narrow force distributions of the bond rupture forces ranging from 200 pN at 1,500 pN/s to 230 pN at 110,000 pN/s. The data are in very good agreement with the standard Bell-Evans model with a single potential barrier at Δx0 = 0.38 nm and a zero-force off-rate koff,0 in the 10-6 s-1 range.

  1. Monodisperse measurement of the biotin-streptavidin interaction strength in a well-defined pulling geometry.

    Science.gov (United States)

    Sedlak, Steffen M; Bauer, Magnus S; Kluger, Carleen; Schendel, Leonard C; Milles, Lukas F; Pippig, Diana A; Gaub, Hermann E

    2017-01-01

    The widely used interaction of the homotetramer streptavidin with the small molecule biotin has been intensively studied by force spectroscopy and has become a model system for receptor ligand interaction. However, streptavidin's tetravalency results in diverse force propagation pathways through the different binding interfaces. This multiplicity gives rise to polydisperse force spectroscopy data. Here, we present an engineered monovalent streptavidin tetramer with a single cysteine in its functional subunit that allows for site-specific immobilization of the molecule, orthogonal to biotin binding. Functionality of streptavidin and its binding properties for biotin remain unaffected. We thus created a stable and reliable molecular anchor with a unique high-affinity binding site for biotinylated molecules or nanoparticles, which we expect to be useful for many single-molecule applications. To characterize the mechanical properties of the bond between biotin and our monovalent streptavidin, we performed force spectroscopy experiments using an atomic force microscope. We were able to conduct measurements at the single-molecule level with 1:1-stoichiometry and a well-defined geometry, in which force exclusively propagates through a single subunit of the streptavidin tetramer. For different force loading rates, we obtained narrow force distributions of the bond rupture forces ranging from 200 pN at 1,500 pN/s to 230 pN at 110,000 pN/s. The data are in very good agreement with the standard Bell-Evans model with a single potential barrier at Δx0 = 0.38 nm and a zero-force off-rate koff,0 in the 10-6 s-1 range.

  2. Measurement of company effectiveness using analytic network process method

    Directory of Open Access Journals (Sweden)

    Goran Janjić

    2017-07-01

    Full Text Available The sustainable development of an organisation is monitored through the organisation’s performance, which beforehand incorporates all stakeholders’ requirements in its strategy. The strategic management concept enables organisations to monitor and evaluate their effectiveness along with efficiency by monitoring of the implementation of set strategic goals. In the process of monitoring and measuring effectiveness, an organisation can use multiple-criteria decision-making methods as help. This study uses the method of analytic network process (ANP to define the weight factors of the mutual influences of all the important elements of an organisation’s strategy. The calculation of an organisation’s effectiveness is based on the weight factors and the degree of fulfilment of the goal values of the strategic map measures. New business conditions influence the changes in the importance of certain elements of an organisation’s business in relation to competitive advantage on the market, and on the market, increasing emphasis is given to non-material resources in the process of selection of the organisation’s most important measures.

  3. Measurement of company effectiveness using analytic network process method

    Science.gov (United States)

    Goran, Janjić; Zorana, Tanasić; Borut, Kosec

    2017-07-01

    The sustainable development of an organisation is monitored through the organisation's performance, which beforehand incorporates all stakeholders' requirements in its strategy. The strategic management concept enables organisations to monitor and evaluate their effectiveness along with efficiency by monitoring of the implementation of set strategic goals. In the process of monitoring and measuring effectiveness, an organisation can use multiple-criteria decision-making methods as help. This study uses the method of analytic network process (ANP) to define the weight factors of the mutual influences of all the important elements of an organisation's strategy. The calculation of an organisation's effectiveness is based on the weight factors and the degree of fulfilment of the goal values of the strategic map measures. New business conditions influence the changes in the importance of certain elements of an organisation's business in relation to competitive advantage on the market, and on the market, increasing emphasis is given to non-material resources in the process of selection of the organisation's most important measures.

  4. Displacement and deformation measurement for large structures by camera network

    Science.gov (United States)

    Shang, Yang; Yu, Qifeng; Yang, Zhen; Xu, Zhiqiang; Zhang, Xiaohu

    2014-03-01

    A displacement and deformation measurement method for large structures by a series-parallel connection camera network is presented. By taking the dynamic monitoring of a large-scale crane in lifting operation as an example, a series-parallel connection camera network is designed, and the displacement and deformation measurement method by using this series-parallel connection camera network is studied. The movement range of the crane body is small, and that of the crane arm is large. The displacement of the crane body, the displacement of the crane arm relative to the body and the deformation of the arm are measured. Compared with a pure series or parallel connection camera network, the designed series-parallel connection camera network can be used to measure not only the movement and displacement of a large structure but also the relative movement and deformation of some interesting parts of the large structure by a relatively simple optical measurement system.

  5. Network Skewness Measures Resilience in Lake Ecosystems

    Science.gov (United States)

    Langdon, P. G.; Wang, R.; Dearing, J.; Zhang, E.; Doncaster, P.; Yang, X.; Yang, H.; Dong, X.; Hu, Z.; Xu, M.; Yanjie, Z.; Shen, J.

    2017-12-01

    Changes in ecosystem resilience defy straightforward quantification from biodiversity metrics, which ignore influences of community structure. Naturally self-organized network structures show positive skewness in the distribution of node connections. Here we test for skewness reduction in lake diatom communities facing anthropogenic stressors, across a network of 273 lakes in China containing 452 diatom species. Species connections show positively skewed distributions in little-impacted lakes, switching to negative skewness in lakes associated with human settlement, surrounding land-use change, and higher phosphorus concentration. Dated sediment cores reveal a down-shifting of network skewness as human impacts intensify, and reversal with recovery from disturbance. The appearance and degree of negative skew presents a new diagnostic for quantifying system resilience and impacts from exogenous forcing on ecosystem communities.

  6. Maslach Burnout Inventory and a Self-Defined, Single-Item Burnout Measure Produce Different Clinician and Staff Burnout Estimates.

    Science.gov (United States)

    Knox, Margae; Willard-Grace, Rachel; Huang, Beatrice; Grumbach, Kevin

    2018-06-04

    Clinicians and healthcare staff report high levels of burnout. Two common burnout assessments are the Maslach Burnout Inventory (MBI) and a single-item, self-defined burnout measure. Relatively little is known about how the measures compare. To identify the sensitivity, specificity, and concurrent validity of the self-defined burnout measure compared to the more established MBI measure. Cross-sectional survey (November 2016-January 2017). Four hundred forty-four primary care clinicians and 606 staff from three San Francisco Aarea healthcare systems. The MBI measure, calculated from a high score on either the emotional exhaustion or cynicism subscale, and a single-item measure of self-defined burnout. Concurrent validity was assessed using a validated, 7-item team culture scale as reported by Willard-Grace et al. (J Am Board Fam Med 27(2):229-38, 2014) and a standard question about workplace atmosphere as reported by Rassolian et al. (JAMA Intern Med 177(7):1036-8, 2017) and Linzer et al. (Ann Intern Med 151(1):28-36, 2009). Similar to other nationally representative burnout estimates, 52% of clinicians (95% CI: 47-57%) and 46% of staff (95% CI: 42-50%) reported high MBI emotional exhaustion or high MBI cynicism. In contrast, 29% of clinicians (95% CI: 25-33%) and 31% of staff (95% CI: 28-35%) reported "definitely burning out" or more severe symptoms on the self-defined burnout measure. The self-defined measure's sensitivity to correctly identify MBI-assessed burnout was 50.4% for clinicians and 58.6% for staff; specificity was 94.7% for clinicians and 92.3% for staff. Area under the receiver operator curve was 0.82 for clinicians and 0.81 for staff. Team culture and atmosphere were significantly associated with both self-defined burnout and the MBI, confirming concurrent validity. Point estimates of burnout notably differ between the self-defined and MBI measures. Compared to the MBI, the self-defined burnout measure misses half of high-burnout clinicians and more

  7. Measuring interoperability maturity in government networks.

    NARCIS (Netherlands)

    Huijsman, K.L.L.G.; Plomp, M.G.A.; Batenburg, R.S.

    2012-01-01

    The purpose of this paper is to create a model that describes the development of interorganisational collaboration in government networks that apply eGovernment. Contrary to several models that describe eGovernment from a government-to-citizen perspective, and primarily emphasise on the front office

  8. Measuring interoperability maturity in government networks

    NARCIS (Netherlands)

    Huijsman, K.L.L.G; Plomp, M.G.A.; Batenburg, R.S.

    2012-01-01

    The purpose of this paper is to create a model that describes the development of interorganisational collaboration in government networks that apply eGovernment. Contrary to several models that describe eGovernment from a government-to-citizen perspective, and primarily emphasise on the front office

  9. Associations of anatomical measures from MRI with radiographically defined knee osteoarthritis score, pain, and physical functioning.

    Science.gov (United States)

    Sowers, Maryfran; Karvonen-Gutierrez, Carrie A; Jacobson, Jon A; Jiang, Yebin; Yosef, Matheos

    2011-02-02

    The prevalence of knee osteoarthritis is traditionally based on radiographic findings, but magnetic resonance imaging is now being used to provide better visualization of bone, cartilage, and soft tissues as well as the patellar compartment. The goal of this study was to estimate the prevalences of knee features defined on magnetic resonance imaging in a population and to relate these abnormalities to knee osteoarthritis severity scores based on radiographic findings, physical functioning, and reported knee pain in middle-aged women. Magnetic resonance images of the knee were evaluated for the location and severity of cartilage defects, bone marrow lesions, osteophytes, subchondral cysts, meniscal and/or ligamentous tears, effusion, and synovitis among 363 middle-aged women (724 knees) from the Michigan Study of Women's Health Across the Nation. These findings were related to Kellgren-Lawrence osteoarthritis severity scores from radiographs, self-reported knee pain, self-reported knee injury, perception of physical functioning, and physical performance measures to assess mobility. Radiographs, physical performance assessment, and interviews were undertaken at the 1996 study baseline and again (with the addition of magnetic resonance imaging assessment) at the follow-up visit during 2007 to 2008. The prevalence of moderate-to-severe knee osteoarthritis changed from 3.7% at the baseline assessment to 26.7% at the follow-up visit eleven years later. Full-thickness cartilage defects of the medial, lateral, and patellofemoral compartments were present in 14.5% (105 knees), 4.6% (thirty-three knees), and 26.2% (190 knees), respectively. Synovitis was identified in 24.7% (179) of the knees, and joint effusions were observed in 70% (507 knees); 21.7% (157) of the knees had complex or macerated meniscal tears. Large osteophytes, marked synovitis, macerated meniscal tears, and full-thickness tibial cartilage defects were associated with increased odds of knee pain and with

  10. Incentivizing and Evaluating Internet-Wide Network Measurements

    Science.gov (United States)

    2014-03-01

    Romania . . . . . . . . . . . . . . . . . . . . . . 62 Figure A.20 Cumulative SCR for Egypt . . . . . . . . . . . . . . . . . . . . . . . 63 Figure A...defined in RFC 1918 [29] and these packets should never be routed in the public Internet. These packets, however, are often filtered in the network core...Turkey, Singapore, Russia, Romania , Pakistan, Philippines, Netherlands, Indonesia, Hun- gary, Guatemala, Finland, Denmark, Switzerland, Brazil

  11. Security measures effect over performance in service provider network

    African Journals Online (AJOL)

    pc

    2018-03-05

    Mar 5, 2018 ... Abstract—network security is defined as a set of policies and actions taken by a ... These threats are linked with the following factors that are ... typically smaller than those in the service provider space. ... Service providers cannot manage to provide ... e the DB performance effect ... r the business needs [10].

  12. Building and measuring a high performance network architecture

    Energy Technology Data Exchange (ETDEWEB)

    Kramer, William T.C.; Toole, Timothy; Fisher, Chuck; Dugan, Jon; Wheeler, David; Wing, William R; Nickless, William; Goddard, Gregory; Corbato, Steven; Love, E. Paul; Daspit, Paul; Edwards, Hal; Mercer, Linden; Koester, David; Decina, Basil; Dart, Eli; Paul Reisinger, Paul; Kurihara, Riki; Zekauskas, Matthew J; Plesset, Eric; Wulf, Julie; Luce, Douglas; Rogers, James; Duncan, Rex; Mauth, Jeffery

    2001-04-20

    Once a year, the SC conferences present a unique opportunity to create and build one of the most complex and highest performance networks in the world. At SC2000, large-scale and complex local and wide area networking connections were demonstrated, including large-scale distributed applications running on different architectures. This project was designed to use the unique opportunity presented at SC2000 to create a testbed network environment and then use that network to demonstrate and evaluate high performance computational and communication applications. This testbed was designed to incorporate many interoperable systems and services and was designed for measurement from the very beginning. The end results were key insights into how to use novel, high performance networking technologies and to accumulate measurements that will give insights into the networks of the future.

  13. Networks of High Mutual Information Define the Structural Proximity of Catalytic Sites: Implications for Catalytic Residue Identification

    DEFF Research Database (Denmark)

    Buslje, Cristina Marino; Teppa, Elin; Di Doménico, Tomas

    2010-01-01

    other non-functional conserved residues. Using a data set of 434 Pfam families included in the catalytic site atlas (CSA) database, we tested this hypothesis and demonstrated that MI can complement amino acid conservation scores to detect CR. The Kullback-Leibler (KL) conservation measurement was shown.......90, the Cls method was found to have a sensitivity of 0.816. In summary, we demonstrate that networks of residues with high MI provide a distinct signature on CR and propose that such a signature should be present in other classes of functional residues where the requirement to maintain a particular function...

  14. Processing horizontal networks measured by integrated terrestrial and GPS technologies

    Directory of Open Access Journals (Sweden)

    Vincent Jakub

    2003-09-01

    Full Text Available Local horizontal networks in which GPS and terrestrial measurements (TER are done are often established at present. Iin other networks, the previous terrestrial measurements can be completed with quantities from contemporary GPS observations (tunnel nets, mining nets with surface and underground parts and other long-shaped nets.The processing of such heterobeneous (GPS, TER networks whose terrestrial measurements are performed as point coordinate measurements (∆X, ∆Y using (geodetic total stationIn is presented in this paper. In such network structures it is then available:- the values ∆X, ∆Y from TER observations which are transformed in the plane of S-JTSK for adjustement,- the values ∆X, ∆Y in the plane S-JTSK that can be obtained by 3D transformation of WGS84 netpoint coordinates from GPS observations to corresponding coordinates S-JTSK.For common adjusting all the ∆X, ∆Y, some elements of the network geometry (e.g. distances should be measured by both methods (GPS, TER. This approach makes possible an effective homogenisation of both network parts what is equivalent to saying that an expressive influence reduction on local frame realizations of S-JTSK in the whole network can be made.Results of network processing obtained in proposed manner are acceptable in general and they are equivalent (accuracy, reliability to results of another processing methods.

  15. Measurements and analysis of online social networks

    OpenAIRE

    González Sánchez, Roberto

    2014-01-01

    Mención Internacional Online Social Networks (OSNs) have become the most used Internet applications attracting hundreds of millions active users every day. The large amount of valuable information in OSNs (not even before available) has attracted the research community to design sophisticated techniques to collect, process, interpret and apply these data into a large range of disciplines including Sociology, Marketing, Computer Science, etc. This thesis presents a series of ...

  16. Measuring interoperability maturity in government networks.

    OpenAIRE

    Huijsman, K.L.L.G.; Plomp, M.G.A.; Batenburg, R.S.

    2012-01-01

    The purpose of this paper is to create a model that describes the development of interorganisational collaboration in government networks that apply eGovernment. Contrary to several models that describe eGovernment from a government-to-citizen perspective, and primarily emphasise on the front office of eGovernment services, this paper focuses on the collaboration that takes place in the back office to enable successful eGovernment services. A maturity model was developed to describe and asses...

  17. A method of reconstructing the spatial measurement network by mobile measurement transmitter for shipbuilding

    International Nuclear Information System (INIS)

    Guo, Siyang; Lin, Jiarui; Yang, Linghui; Ren, Yongjie; Guo, Yin

    2017-01-01

    The workshop Measurement Position System (wMPS) is a distributed measurement system which is suitable for the large-scale metrology. However, there are some inevitable measurement problems in the shipbuilding industry, such as the restriction by obstacles and limited measurement range. To deal with these factors, this paper presents a method of reconstructing the spatial measurement network by mobile transmitter. A high-precision coordinate control network with more than six target points is established. The mobile measuring transmitter can be added into the measurement network using this coordinate control network with the spatial resection method. This method reconstructs the measurement network and broadens the measurement scope efficiently. To verify this method, two comparison experiments are designed with the laser tracker as the reference. The results demonstrate that the accuracy of point-to-point length is better than 0.4mm and the accuracy of coordinate measurement is better than 0.6mm. (paper)

  18. Defining, Designing for, and Measuring "Social Constructivist Digital Literacy" Development in Learners: A Proposed Framework

    Science.gov (United States)

    Reynolds, Rebecca

    2016-01-01

    This paper offers a newly conceptualized modular framework for digital literacy that defines this concept as a task-driven "social constructivist digital literacy," comprising 6 practice domains grounded in Constructionism and social constructivism: Create, Manage, Publish, Socialize, Research, Surf. The framework articulates possible…

  19. Experimental demonstration of bandwidth on demand (BoD) provisioning based on time scheduling in software-defined multi-domain optical networks

    Science.gov (United States)

    Zhao, Yongli; Li, Yajie; Wang, Xinbo; Chen, Bowen; Zhang, Jie

    2016-09-01

    A hierarchical software-defined networking (SDN) control architecture is designed for multi-domain optical networks with the Open Daylight (ODL) controller. The OpenFlow-based Control Virtual Network Interface (CVNI) protocol is deployed between the network orchestrator and the domain controllers. Then, a dynamic bandwidth on demand (BoD) provisioning solution is proposed based on time scheduling in software-defined multi-domain optical networks (SD-MDON). Shared Risk Link Groups (SRLG)-disjoint routing schemes are adopted to separate each tenant for reliability. The SD-MDON testbed is built based on the proposed hierarchical control architecture. Then the proposed time scheduling-based BoD (Ts-BoD) solution is experimentally demonstrated on the testbed. The performance of the Ts-BoD solution is evaluated with respect to blocking probability, resource utilization, and lightpath setup latency.

  20. Template measurement for plutonium pit based on neural networks

    International Nuclear Information System (INIS)

    Zhang Changfan; Gong Jian; Liu Suping; Hu Guangchun; Xiang Yongchun

    2012-01-01

    Template measurement for plutonium pit extracts characteristic data from-ray spectrum and the neutron counts emitted by plutonium. The characteristic data of the suspicious object are compared with data of the declared plutonium pit to verify if they are of the same type. In this paper, neural networks are enhanced as the comparison algorithm for template measurement of plutonium pit. Two kinds of neural networks are created, i.e. the BP and LVQ neural networks. They are applied in different aspects for the template measurement and identification. BP neural network is used for classification for different types of plutonium pits, which is often used for management of nuclear materials. LVQ neural network is used for comparison of inspected objects to the declared one, which is usually applied in the field of nuclear disarmament and verification. (authors)

  1. EMULACIÓN DE ESCENARIOS VIRTUALES, EN UNA SDWLAN (SOFTWARE DEFINED WIRELESS LOCAL AREA NETWORK, DE UN CAMPUS UNIVERSITARIO

    Directory of Open Access Journals (Sweden)

    Gerlyn Duarte

    2015-07-01

    Full Text Available Las redes definidas por software (SDN = Software Defined Network es una arquitectura de red emergente que se destaca como una tecnología capaz de ofrecer un control más flexible y dinámico a la hora de gestionar el diseño y funciones de la red, donde se separan los planos de control y enrutamiento. Esto permite la centralización de los controles de la red basada en software. Se puede decir que es posible tener flexibilidad y rapidez al momento de configurar, implementar y administrar diferentes protocolos personalizados para los requerimientos de distintas redes. Actualmente, en una red convencional, cada conmutador y/o enrutador tienen software propietario que le dice qué hacer. SDN se centra principalmente en la parte cableada de la red de datos. Sin embargo, todas las ventajas de las SDN sólo se obtienen si se logra abarcar la totalidad de la infraestructura, desde el centro de datos al extremo de la red, permitiendo extender todos los beneficios de SDN hasta la red inalámbrica, para conseguir a su vez una red inalámbrica de área local definida por software (SDWLAN = Software Define Wireless Local Area Network. Es por ello que en el presente trabajo, se emuló parte de una SDWLAN de un campus universitario para observar la factibilidad de implementar SDN en la misma. Para la emulación se utilizó una variante del emulador Mininet que permite trabajar con redes inalámbricas. De igual forma, se efectuaron mediciones del ancho de banda de las SDWLAN emuladas, así como la interconectividad entre ellas. Se evidenció la facilidad y el rendimiento de trabajar con las herramientas de emulación de SDWLAN empleadas, permitiendo de igual forma la estructuración de distintas topologías de SDWLAN. Se comprobó que el emulador, el cual está aún en la fase beta, permite interactuar y ejecutar cualquier proceso como si se ejecutara directamente en un equipo con GNU/Linux de forma eficaz.

  2. Implementasi Wireless Quality of Service dengan Metode Load Switching Jaringan Seluler Menggunakan Software Defined Network untuk Meningkatkan Network Reliability pada Jaringan Dinamis

    Directory of Open Access Journals (Sweden)

    Yoga Bayu Aji Pranawa

    2017-03-01

    Full Text Available Wireless Quality of Service (QOS adalah salah satu dimensi mobilitas, yaitu sebuah metode yang digunakan untuk menjaga kualitas suatu jaringan nirkabel. QOS diperlukan sebagai sebuah metode untuk memenuhi kriteria pelayanan sistem bagi pengguna, yaitu confidentiality, integrity, dan availability. Beberapa aspek yang menjadi topik utama dalam QOS adalah failure and recovery mechanism, variable bandwidth, computing distribution, discovery mechanism, variable lantency, dan performance feedback. Wireless yang dibahas pada penelitian ini dititik beratkan pada jaringan seluler yang cenderung tidak reliable pada daerah tertentu. Oleh karena itu dibutuhkan sebuah mekanisme yang dapat mengatasi tidak stabilnya jaringan seluler tersebut. mplementasi mekanisme yang diterapkan pada penelitian ini adalah dengan menerapkan load switching pada jaringan seluler dengan menggunakan beberapa provider dan menerapkan teknologi Software Defined Network (SDN. Berdasarkan hasi uji coba dapat disimpulkan bahwa sistem yang dibuat pada penelitian ini dapat menerapkan wireless quality of service dan meningkatkan network reliability sebesar 65,29% dan 83,87% lebih baik untuk penggunaan tanpa waktu tunggu dan dengan waktu tunggu pada suatu jaringan  dinamis.

  3. Optimizing bulk data transfers using network measurements: A practical case

    International Nuclear Information System (INIS)

    Ciuffoletti, A; Merola, L; Palmieri, F; Russo, G; Pardi, S

    2010-01-01

    In modern Data Grid infrastructures, we increasingly face the problem of providing the running applications with fast and reliable access to large data volumes, often geographically distributed across the network. As a direct consequence, the concept of replication has been adopted by the grid community to increase data availability and maximize job throughput. To be really effective, such process has to be driven by specific optimization strategies that define when and where replicas should be created or deleted on a per-site basis, and which replicas a job should use. These strategies have to take into account the available network bandwidth as a primary resource, prior to any consideration about storage or processing power. We present a novel replica management service, integrated within the Gluedomains active network monitoring architecture, designed and implemented within the centralized collective middleware framework of the SCoPE project to provide network-aware transfer services for data intensive Grid applications.

  4. Vector network analyzer (VNA) measurements and uncertainty assessment

    CERN Document Server

    Shoaib, Nosherwan

    2017-01-01

    This book describes vector network analyzer measurements and uncertainty assessments, particularly in waveguide test-set environments, in order to establish their compatibility to the International System of Units (SI) for accurate and reliable characterization of communication networks. It proposes a fully analytical approach to measurement uncertainty evaluation, while also highlighting the interaction and the linear propagation of different uncertainty sources to compute the final uncertainties associated with the measurements. The book subsequently discusses the dimensional characterization of waveguide standards and the quality of the vector network analyzer (VNA) calibration techniques. The book concludes with an in-depth description of the novel verification artefacts used to assess the performance of the VNAs. It offers a comprehensive reference guide for beginners to experts, in both academia and industry, whose work involves the field of network analysis, instrumentation and measurements.

  5. Cost-aware request routing in multi-geography cloud data centres using software-defined networking

    Science.gov (United States)

    Yuan, Haitao; Bi, Jing; Li, Bo Hu; Tan, Wei

    2017-03-01

    Current geographically distributed cloud data centres (CDCs) require gigantic energy and bandwidth costs to provide multiple cloud applications to users around the world. Previous studies only focus on energy cost minimisation in distributed CDCs. However, a CDC provider needs to deliver gigantic data between users and distributed CDCs through internet service providers (ISPs). Geographical diversity of bandwidth and energy costs brings a highly challenging problem of how to minimise the total cost of a CDC provider. With the recently emerging software-defined networking, we study the total cost minimisation problem for a CDC provider by exploiting geographical diversity of energy and bandwidth costs. We formulate the total cost minimisation problem as a mixed integer non-linear programming (MINLP). Then, we develop heuristic algorithms to solve the problem and to provide a cost-aware request routing for joint optimisation of the selection of ISPs and the number of servers in distributed CDCs. Besides, to tackle the dynamic workload in distributed CDCs, this article proposes a regression-based workload prediction method to obtain future incoming workload. Finally, this work evaluates the cost-aware request routing by trace-driven simulation and compares it with the existing approaches to demonstrate its effectiveness.

  6. Transaction costs and social networks in productivity measurement

    DEFF Research Database (Denmark)

    Henningsen, Geraldine; Henningsen, Arne; Henning, Christian H. C. A.

    2015-01-01

    . Hence, both the absolute productivity measures and, more importantly, the productivity ranking will be distorted. A major driver of transaction costs is poor access to information and contract enforcement assistance. Social networks often catalyse information exchange as well as generate trust...... and support. Hence, we use measures of a firm’s access to social networks as a proxy for the transaction costs the firm faces. We develop a microeconomic production model that takes into account transaction costs and networks. Using a data set of 384 Polish farms, we empirically estimate this model...... and compare different parametric, semiparametric, and nonparametric model specifications. Our results generally support our hypothesis. Especially, large trading networks and dense household networks have a positive influence on a farm’s productivity. Furthermore, our results indicate that transaction costs...

  7. Defining Allowable Physical Property Variations for High Accurate Measurements on Polymer Parts

    DEFF Research Database (Denmark)

    Mohammadi, Ali; Sonne, Mads Rostgaard; Madruga, Daniel González

    2015-01-01

    Measurement conditions and material properties have a significant impact on the dimensions of a part, especially for polymers parts. Temperature variation causes part deformations that increase the uncertainty of the measurement process. Current industrial tolerances of a few micrometres demand...... high accurate measurements in non-controlled ambient. Most of polymer parts are manufactured by injection moulding and their inspection is carried out after stabilization, around 200 hours. The overall goal of this work is to reach ±5μm in uncertainty measurements a polymer products which...

  8. Network neighborhood analysis with the multi-node topological overlap measure.

    Science.gov (United States)

    Li, Ai; Horvath, Steve

    2007-01-15

    The goal of neighborhood analysis is to find a set of genes (the neighborhood) that is similar to an initial 'seed' set of genes. Neighborhood analysis methods for network data are important in systems biology. If individual network connections are susceptible to noise, it can be advantageous to define neighborhoods on the basis of a robust interconnectedness measure, e.g. the topological overlap measure. Since the use of multiple nodes in the seed set may lead to more informative neighborhoods, it can be advantageous to define multi-node similarity measures. The pairwise topological overlap measure is generalized to multiple network nodes and subsequently used in a recursive neighborhood construction method. A local permutation scheme is used to determine the neighborhood size. Using four network applications and a simulated example, we provide empirical evidence that the resulting neighborhoods are biologically meaningful, e.g. we use neighborhood analysis to identify brain cancer related genes. An executable Windows program and tutorial for multi-node topological overlap measure (MTOM) based analysis can be downloaded from the webpage (http://www.genetics.ucla.edu/labs/horvath/MTOM/).

  9. Defining and measuring the mean residence time of lateral surface transient storage zones in small streams

    Science.gov (United States)

    T.R. Jackson; R. Haggerty; S.V. Apte; A. Coleman; K.J. Drost

    2012-01-01

    Surface transient storage (STS) has functional significance in stream ecosystems because it increases solute interaction with sediments. After volume, mean residence time is the most important metric of STS, but it is unclear how this can be measured accurately or related to other timescales and field-measureable parameters. We studied mean residence time of lateral...

  10. Defining and measuring cyberbullying within the larger context of bullying victimization.

    Science.gov (United States)

    Ybarra, Michele L; Boyd, Danah; Korchmaros, Josephine D; Oppenheim, Jay Koby

    2012-07-01

    To inform the scientific debate about bullying, including cyberbullying, measurement. Two split-form surveys were conducted online among 6-17-year-olds (n = 1,200 each) to inform recommendations for cyberbullying measurement. Measures that use the word "bully" result in prevalence rates similar to each other, irrespective of whether a definition is included, whereas measures not using the word "bully" are similar to each other, irrespective of whether a definition is included. A behavioral list of bullying experiences without either a definition or the word "bully" results in higher prevalence rates and likely measures experiences that are beyond the definition of "bullying." Follow-up questions querying differential power, repetition, and bullying over time were used to examine misclassification. The measure using a definition but not the word "bully" appeared to have the highest rate of false positives and, therefore, the highest rate of misclassification. Across two studies, an average of 25% reported being bullied at least monthly in person compared with an average of 10% bullied online, 7% via telephone (cell or landline), and 8% via text messaging. Measures of bullying among English-speaking individuals in the United States should include the word "bully" when possible. The definition may be a useful tool for researchers, but results suggest that it does not necessarily yield a more rigorous measure of bullying victimization. Directly measuring aspects of bullying (i.e., differential power, repetition, over time) reduces misclassification. To prevent double counting across domains, we suggest the following distinctions: mode (e.g., online, in-person), type (e.g., verbal, relational), and environment (e.g., school, home). We conceptualize cyberbullying as bullying communicated through the online mode. Copyright © 2012 Society for Adolescent Health and Medicine. Published by Elsevier Inc. All rights reserved.

  11. Premises and Limitations in Defining and Measuring Synergy from M&As

    Directory of Open Access Journals (Sweden)

    Aevoae George Marian

    2017-01-01

    Full Text Available Mergers and acquisitions are performed worldwide mainly because of synergy. Although many invoke the term synergy as the key motivation of why they engage in M&As, research has led us to understand that it is not very clear in terms of what it actually is. In the scientific literature, synergy is mostly defined as being “2+2=5”. Thus, we first thought that it can only be a positive effect. But, latter on, we found out that synergy is not only positive, it can be negative as well, known as negative synergy or dyssynergy. The purpose of this paper is to shed some light on what is synergy, how can we quantify and classify it and why acquiring firms tend to pay more for the target firm. We believe that there is a link between the amount of premium paid for a target firm and the expectations for synergy.

  12. AmeriFlux Measurement Network: Science Team Research

    Energy Technology Data Exchange (ETDEWEB)

    Law, B E

    2012-12-12

    Research involves analysis and field direction of AmeriFlux operations, and the PI provides scientific leadership of the AmeriFlux network. Activities include the coordination and quality assurance of measurements across AmeriFlux network sites, synthesis of results across the network, organizing and supporting the annual Science Team Meeting, and communicating AmeriFlux results to the scientific community and other users. Objectives of measurement research include (i) coordination of flux and biometric measurement protocols (ii) timely data delivery to the Carbon Dioxide Information and Analysis Center (CDIAC); and (iii) assurance of data quality of flux and ecosystem measurements contributed by AmeriFlux sites. Objectives of integration and synthesis activities include (i) integration of site data into network-wide synthesis products; and (ii) participation in the analysis, modeling and interpretation of network data products. Communications objectives include (i) organizing an annual meeting of AmeriFlux investigators for reporting annual flux measurements and exchanging scientific information on ecosystem carbon budgets; (ii) developing focused topics for analysis and publication; and (iii) developing data reporting protocols in support of AmeriFlux network goals.

  13. Defining and Measuring Decision-Making for the Management of Trauma Patients.

    Science.gov (United States)

    Madani, Amin; Gips, Amanda; Razek, Tarek; Deckelbaum, Dan L; Mulder, David S; Grushka, Jeremy R

    Effective management of trauma patients is heavily dependent on sound judgment and decision-making. Yet, current methods for training and assessing these advanced cognitive skills are subjective, lack standardization, and are prone to error. This qualitative study aims to define and characterize the cognitive and interpersonal competencies required to optimally manage injured patients. Cognitive and hierarchical task analyses for managing unstable trauma patients were performed using qualitative methods to map the thoughts, behaviors, and practices that characterize expert performance. Trauma team leaders and board-certified trauma surgeons participated in semistructured interviews that were transcribed verbatim. Data were supplemented with content from published literature and prospectively collected field notes from observations of the trauma team during trauma activations. The data were coded and analyzed using grounded theory by 2 independent reviewers. A framework was created based on 14 interviews with experts (lasting 1-2 hours each), 35 field observations (20 [57%] blunt; 15 [43%] penetrating; median Injury Severity Score 20 [13-25]), and 15 literary sources. Experts included 11 trauma surgeons and 3 emergency physicians from 7 Level 1 academic institutions in North America (median years in practice: 12 [8-17]). Twenty-nine competencies were identified, including 17 (59%) related to situation awareness, 6 (21%) involving decision-making, and 6 (21%) requiring interpersonal skills. Of 40 potential errors that were identified, root causes were mapped to errors in situation awareness (20 [50%]), decision-making (10 [25%]), or interpersonal skills (10 [25%]). This study defines cognitive and interpersonal competencies that are essential for the management of trauma patients. This framework may serve as the basis for novel curricula to train and assess decision-making skills, and to develop quality-control metrics to improve team and individual performance

  14. Defining, Measuring, and Incentivizing Sustainable Land Use to Meet Human Needs

    Science.gov (United States)

    Nicholas, K. A.; Brady, M. V.; Olin, S.; Ekroos, J.; Hall, M.; Seaquist, J. W.; Lehsten, V.; Smith, H.

    2016-12-01

    Land is a natural capital that supports the flow of an enormous amount of ecosystem services critical to human welfare. Sustainable land use, which we define as land use that meets both current and future human needs for ecosystem services, is essential to meet global goals for climate mitigation and sustainable development, while maintaining natural capital. However, it is not clear what governance is needed to achieve sustainable land use under multiple goals (as defined by the values of relevant decision-makers and land managers), particularly under climate change. Here we develop a conceptual model for examining the interactions and tradeoffs among multiple goals, as well as their spatial interactions (teleconnections), in research developed using Design Thinking principles. We have selected five metrics for provisioning (food production, and fiber production for wood and energy), regulating and maintenance (climate mitigation and biodiversity conservation), and cultural (heritage) ecosystem services. Using the case of Sweden, we estimate indicators for these metrics using a combination of existing data synthesis and process-based simulation modeling. We also develop and analyze new indicators (e.g., combining data on land use, bird conservation status, and habitat specificity to make a predictive model of bird diversity changes on agricultural or forested land). Our results highlight both expected tradeoffs (e.g., between food production and biodiversity conservation) as well as unexpected opportunities for synergies under different land management scenarios and strategies. Our model also provides a practical way to make decision-maker values explicit by comparing both quantity and preferences for bundles of ecosystem services under various scenarios. We hope our model will help in considering competing interests and shaping economic incentives and governance structures to meet national targets in support of global goals for sustainable management of land

  15. Pyramidal resistor networks for electrical impedance tomography with partial boundary measurements

    International Nuclear Information System (INIS)

    Borcea, L; Mamonov, A V; Druskin, V; Vasquez, F Guevara

    2010-01-01

    We introduce an inversion algorithm for electrical impedance tomography (EIT) with partial boundary measurements in two dimensions. It gives stable and fast reconstructions using sparse parameterizations of the unknown conductivity on optimal grids that are computed as part of the inversion. We follow the approach in Borcea et al (2008 Inverse Problems 24 035013) and Vasquez (2006 PhD thesis Rice University, Houston, TX, USA) that connects inverse discrete problems for resistor networks to continuum EIT problems, using optimal grids. The algorithm in Borcea et al (2008 Inverse Problems 24 035013) and Vasquez (2006 PhD Thesis Rice University, Houston, TX, USA) is based on circular resistor networks, and solves the EIT problem with full boundary measurements. It is extended in Borcea et al (2010 Inverse Problems 26 045010) to EIT with partial boundary measurements, using extremal quasi-conformal mappings that transform the problem to one with full boundary measurements. Here we introduce a different class of optimal grids, based on resistor networks with pyramidal topology, that is better suited for the partial measurements setup. We prove the unique solvability of the discrete inverse problem for these networks and develop an algorithm for finding them from the measurements of the Dirichlet to Neumann map. Then, we show how to use the networks to define the optimal grids and to approximate the unknown conductivity. We assess the performance of our approach with numerical simulations and compare the results with those in Borcea et al (2010)

  16. Tariffing of energy measured consumers in the distribution network

    International Nuclear Information System (INIS)

    2006-01-01

    Criteria for socio-economic effective tariffing of energy-measured clients in the distribution network are discussed (i.e. households, leisure homes and smaller business clients), this means consumers that do not have hourly measurements or effect measurements. The tariffs should be based on variable segments that reflect short-term marginal costs in the network (in practice loss of transfer) and fixed segments that to the least extent possible influence the consumers' decisions in the choice of energy solutions, both in short term and long term. High-priced energy segments and effect based fixed segments may give unfortunate socio-economic price signals compared to the marginal long-term network costs. A fixed segment per measurement unit is in principle completely neutral, but it is to some extent vulnerable to strategic adjustments if the consumers choose collective measurement. This is not necessarily a big problem in practice (author)

  17. Local difference measures between complex networks for dynamical system model evaluation.

    Science.gov (United States)

    Lange, Stefan; Donges, Jonathan F; Volkholz, Jan; Kurths, Jürgen

    2015-01-01

    A faithful modeling of real-world dynamical systems necessitates model evaluation. A recent promising methodological approach to this problem has been based on complex networks, which in turn have proven useful for the characterization of dynamical systems. In this context, we introduce three local network difference measures and demonstrate their capabilities in the field of climate modeling, where these measures facilitate a spatially explicit model evaluation.Building on a recent study by Feldhoff et al. [8] we comparatively analyze statistical and dynamical regional climate simulations of the South American monsoon system [corrected]. types of climate networks representing different aspects of rainfall dynamics are constructed from the modeled precipitation space-time series. Specifically, we define simple graphs based on positive as well as negative rank correlations between rainfall anomaly time series at different locations, and such based on spatial synchronizations of extreme rain events. An evaluation against respective networks built from daily satellite data provided by the Tropical Rainfall Measuring Mission 3B42 V7 reveals far greater differences in model performance between network types for a fixed but arbitrary climate model than between climate models for a fixed but arbitrary network type. We identify two sources of uncertainty in this respect. Firstly, climate variability limits fidelity, particularly in the case of the extreme event network; and secondly, larger geographical link lengths render link misplacements more likely, most notably in the case of the anticorrelation network; both contributions are quantified using suitable ensembles of surrogate networks. Our model evaluation approach is applicable to any multidimensional dynamical system and especially our simple graph difference measures are highly versatile as the graphs to be compared may be constructed in whatever way required. Generalizations to directed as well as edge- and node

  18. Defining and measuring suspicion of sepsis: an analysis of routine data.

    Science.gov (United States)

    Inada-Kim, Matthew; Page, Bethan; Maqsood, Imran; Vincent, Charles

    2017-06-09

    To define the target population of patients who have suspicion of sepsis (SOS) and to provide a basis for assessing the burden of SOS, and the evaluation of sepsis guidelines and improvement programmes. Retrospective analysis of routinely collected hospital administrative data. Secondary care, eight National Health Service (NHS) Acute Trusts. Hospital Episode Statistics data for 2013-2014 was used to identify all admissions with a primary diagnosis listed in the 'suspicion of sepsis' (SOS) coding set. The SOS coding set consists of all bacterial infective diagnoses. We identified 47 475 admissions with SOS, equivalent to a rate of 17 admissions per 1000 adults in a given year. The mortality for this group was 7.2% during their acute hospital admission. Urinary tract infection was the most common diagnosis and lobar pneumonia was associated with the most deaths. A short list of 10 diagnoses can account for 85% of the deaths. Patients with SOS can be identified in routine administrative data. It is these patients who should be screened for sepsis and are the target of programmes to improve the detection and treatment of sepsis. The effectiveness of such programmes can be evaluated by examining the outcomes of patients with SOS. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  19. Comparison of measured and calculated doses for narrow MLC defined fields

    International Nuclear Information System (INIS)

    Lydon, J.; Rozenfeld, A.; Lerch, M.

    2002-01-01

    Full text: The introduction of Intensity Modulated Radiotherapy (IMRT) has led to the use of narrow fields in the delivery of radiation doses to patients. Such fields are not well characterized by calculation methods commonly used in radiotherapy treatment planning systems. The accuracy of the dose calculation algorithm must therefore be investigated prior to clinical use. This study looked at symmetrical and asymmetrical 0.1 to 3cm wide fields delivered with a Varian CL2100C 6MV photon beam. Measured doses were compared to doses calculated using Pinnacle, the ADAC radiotherapy treatment planning system. Two high resolution methods of measuring dose were used. A MOSFET detector in a water phantom and radiographic film in a solid water phantom with spatial resolutions of 10 and 89μm respectively. Dose calculations were performed using the collapsed cone convolution algorithm in Pinnacle with a 0.1cm dose calculation grid in the MLC direction. The effect of Pinnacle not taking into account the rounded leaf ends was simulated by offsetting the leaves by 0.1cm in the dose calculation. Agreement between measurement and calculation is good for fields of 1cm and wider. However, fields of less than 1cm width can show a significant difference between measurement and calculation

  20. Impedance measurements and high-resolution manometry help to better define rumination episodes

    NARCIS (Netherlands)

    Kessing, Boudewijn F.; Govaert, Frank; Masclee, Ad A. M.; Conchillo, José M.

    2011-01-01

    Rumination syndrome is a disorder of unknown etiology characterized by regurgitation of recently ingested food. We aimed to improve the diagnosis of rumination syndrome by classification of separate rumination symptoms using (1) an ambulatory manometry/impedance (AMIM) measurement and (2) a

  1. Design and performance evaluation of an OpenFlow-based control plane for software-defined elastic optical networks with direct-detection optical OFDM (DDO-OFDM) transmission.

    Science.gov (United States)

    Liu, Lei; Peng, Wei-Ren; Casellas, Ramon; Tsuritani, Takehiro; Morita, Itsuro; Martínez, Ricardo; Muñoz, Raül; Yoo, S J B

    2014-01-13

    Optical Orthogonal Frequency Division Multiplexing (O-OFDM), which transmits high speed optical signals using multiple spectrally overlapped lower-speed subcarriers, is a promising candidate for supporting future elastic optical networks. In contrast to previous works which focus on Coherent Optical OFDM (CO-OFDM), in this paper, we consider the direct-detection optical OFDM (DDO-OFDM) as the transport technique, which leads to simpler hardware and software realizations, potentially offering a low-cost solution for elastic optical networks, especially in metro networks, and short or medium distance core networks. Based on this network scenario, we design and deploy a software-defined networking (SDN) control plane enabled by extending OpenFlow, detailing the network architecture, the routing and spectrum assignment algorithm, OpenFlow protocol extensions and the experimental validation. To the best of our knowledge, it is the first time that an OpenFlow-based control plane is reported and its performance is quantitatively measured in an elastic optical network with DDO-OFDM transmission.

  2. Information loss method to measure node similarity in networks

    Science.gov (United States)

    Li, Yongli; Luo, Peng; Wu, Chong

    2014-09-01

    Similarity measurement for the network node has been paid increasing attention in the field of statistical physics. In this paper, we propose an entropy-based information loss method to measure the node similarity. The whole model is established based on this idea that less information loss is caused by seeing two more similar nodes as the same. The proposed new method has relatively low algorithm complexity, making it less time-consuming and more efficient to deal with the large scale real-world network. In order to clarify its availability and accuracy, this new approach was compared with some other selected approaches on two artificial examples and synthetic networks. Furthermore, the proposed method is also successfully applied to predict the network evolution and predict the unknown nodes' attributions in the two application examples.

  3. Measuring network competence in buyer-supplier relationships

    Directory of Open Access Journals (Sweden)

    Gert Human

    2011-04-01

    Full Text Available Managing multiple buyer-seller relationships in business-to-business networks demands an understanding of a firm’s competence to manage in an interconnected environment.  This paper reports on an attempt to measure network competence by using the NetCompTest scale in business-to-business markets in South Africa. Based on a pilot study refinement, the paper proposes an adjusted measurement scale and details the results of a second round of measurement conducted amongst 495 business-to-business managers in South Africa. The results established partial support for the use of the NetCompTest scale in a South African context, and analysis of variance indicated that some differences in the measurement based on firm and individual characteristics can be observed in the data. The paper assists in theory-building and provides managerial insights for managing buyer-supplier relationships in networks.

  4. Time Synchronized Wireless Sensor Network for Vibration Measurement

    Science.gov (United States)

    Uchimura, Yutaka; Nasu, Tadashi; Takahashi, Motoichi

    Network based wireless sensing has become an important area of research and various new applications for remote sensing are expected to emerge. One of the promising applications is structural health monitoring of building or civil engineering structure and it often requires vibration measurement. For the vibration measurement via wireless network, time synchronization is indispensable. In this paper, we introduce a newly developed time synchronized wireless sensor network system. The system employs IEEE 802.11 standard based TSF counter and sends the measured data with the counter value. TSF based synchronization enables consistency on common clock among different wireless nodes. We consider the scale effect on the synchronization accuracy and the effect is evaluated by stochastic analysis and simulation studies. A new wireless sensing system is developed and the hardware and software specifications are shown. The experiments are conducted in a reinforced concrete building and results show good performance enough for vibration measurement purpose.

  5. Link-quality measurement and reporting in wireless sensor networks.

    Science.gov (United States)

    Chehri, Abdellah; Jeon, Gwanggil; Choi, Byoungjo

    2013-03-04

    Wireless Sensor networks (WSNs) are created by small hardware devices that possess the necessary functionalities to measure and exchange a variety of environmental data in their deployment setting. In this paper, we discuss the experiments in deploying a testbed as a first step towards creating a fully functional heterogeneous wireless network-based underground monitoring system. The system is mainly composed of mobile and static ZigBee nodes, which are deployed on the underground mine galleries for measuring ambient temperature. In addition, we describe the measured results of link characteristics such as received signal strength, latency and throughput for different scenarios.

  6. Link-Quality Measurement and Reporting in Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Byoungjo Choi

    2013-03-01

    Full Text Available Wireless Sensor networks (WSNs are created by small hardware devices that possess the necessary functionalities to measure and exchange a variety of environmental data in their deployment setting. In this paper, we discuss the experiments in deploying a testbed as a first step towards creating a fully functional heterogeneous wireless network-based underground monitoring system. The system is mainly composed of mobile and static ZigBee nodes, which are deployed on the underground mine galleries for measuring ambient temperature. In addition, we describe the measured results of link characteristics such as received signal strength, latency and throughput for different scenarios.

  7. Defining and measuring integrated patient care: promoting the next frontier in health care delivery.

    Science.gov (United States)

    Singer, Sara J; Burgers, Jako; Friedberg, Mark; Rosenthal, Meredith B; Leape, Lucian; Schneider, Eric

    2011-02-01

    Integration of care is emerging as a central challenge of health care delivery, particularly for patients with multiple, complex chronic conditions. The authors argue that the concept of "integrated patient care" would benefit from further clarification regarding (a) the object of integration and (b) its essential components, particularly when constructing measures.To address these issues, the authors propose a definition of integrated patient care that distinguishes it from integrated delivery organizations, acknowledging that integrated organizational structures and processes may fail to produce integrated patient care. The definition emphasizes patients' central role as active participants in managing their own health by including patient centeredness as a key element of integrated patient care. Measures based on the proposed definition will enable empirical assessment of the potential relationships between the integration of organizations, the integration of patient care, and patient outcomes, providing valuable guidance to health systems reformers.

  8. A working group for Japanese nuclear data measurement network

    International Nuclear Information System (INIS)

    Watanabe, Yukinobu

    2013-01-01

    A new working group in the Japanese Nuclear Data Committee has been established to make a cooperative network among researchers involved in nuclear data measurements and to discuss the strategy for nuclear data measurements. The working group activities are reported. (author)

  9. Measuring replication competent HIV-1: advances and challenges in defining the latent reservoir

    OpenAIRE

    Wang, Zheng; Simonetti, Francesco R.; Siliciano, Robert F.; Laird, Gregory M.

    2018-01-01

    Antiretroviral therapy cannot cure HIV-1 infection due to the persistence of a small number of latently infected cells harboring replication-competent proviruses. Measuring persistent HIV-1 is challenging, as it consists of a mosaic population of defective and intact proviruses that can shift from a state of latency to active HIV-1 transcription. Due to this complexity, most of the current assays detect multiple categories of persistent HIV-1, leading to an overestimate of the true size of th...

  10. Anatomic guidelines defined by reformatting images on MRI for volume measurement of amygdala and hippocampus

    International Nuclear Information System (INIS)

    Hoshida, Tohru; Sakaki, Toshisuke; Uematsu, Sumio.

    1995-01-01

    Twelve patients with intractable partial epilepsy underwent MR scans at the Epilepsy Center of the Johns Hopkins Hospital. There were five women and seven men, ranging in age from five to 51 years (mean age: 26 years). Coronal images were obtained using a 3-D SPGR. The coronal images were transferred to an Allegro 5.1 workstation, and reformatted along the cardinal axes (axial and sagittal) in multiple view points. The anterior end of the amygdala was measured at the level just posterior to the disappearance of the temporal stem. The semilunar gyrus of the amygdala was separated from the ambient gyrus by the semianular sulcus that forms the boundary between the amygdala and the entorhinal cortex. The delineation of the hippocampal formation included the subicular complex, hippocampal proper, dentate gyrus, alveus, and fimbria. The uncal cleft separated the uncus above from the parahippocampal gyrus below. The roof of this cleft was formed by the hippocampus and the dentate gyrus, and the floor, by the presubiculum and subiculum. Although using some guidelines, strictly separating the hippocampal head from the posterior part of the amygdala was not feasible as was previously reported, because of the isointensity on MRI between the cortex of the amygdala and the hippocampus. The most posterior portion of the hippocampus was measured at the level of the subsplenial gyri, just below the splenium of the corpus callosum, to measure the hippocampal volume in its near totality. Therefore, it is reliable, and clinically useful, to measure the combined total volume of the amygdala and the hippocampus when comparing results with those of other centers. (S.Y.)

  11. The Criterion A problem revisited: controversies and challenges in defining and measuring psychological trauma.

    Science.gov (United States)

    Weathers, Frank W; Keane, Terence M

    2007-04-01

    The Criterion A problem in the field of traumatic stress refers to the stressor criterion for posttraumatic stress disorder (PTSD) and involves a number of fundamental issues regarding the definition and measurement of psychological trauma. These issues first emerged with the introduction of PTSD as a diagnostic category in the Diagnostic and Statistical Manual of Mental Disorders, Third Edition (DSM-III; American Psychiatric Association, 1980) and continue to generate considerable controversy. In this article, the authors provide an update on the Criterion A problem, with particular emphasis on the evolution of the DSM definition of the stressor criterion and the ongoing debate regarding broad versus narrow conceptualizations of traumatic events.

  12. Using a management perspective to define and measure changes in nursing technology.

    Science.gov (United States)

    Alexander, J W; Kroposki, M

    2001-09-01

    The aims of this paper are to discuss the uses of the concept of technology from the medical science and the management perspectives; to propose a clear definition of nursing technology; and to present a study applying the use of the concept of nursing technology on nursing units. Nurse managers must use management terms correctly and the term technology may be misleading for some. A review of the nursing literature shows varied uses of the concept of technology. Thus a discussion of the dimensions, attributes, consequences, and definitions of nursing technology from the management perspective are given. A longitudinal study to measure the dimensions of nursing technology on nursing units 10 years apart. The findings suggest that the dimensions of nursing technology change over time and support the need for nurse managers to periodically assess nursing technology before making management changes at the level of the nursing unit. This study helps health care providers understand the unique role of nurses as healthcare professionals by identifying and measuring nursing technology on the nursing unit.

  13. A quantitative approach to measure road network information based on edge diversity

    Science.gov (United States)

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

    2015-12-01

    The measure of map information has been one of the key issues in assessing cartographic quality and map generalization algorithms. It is also important for developing efficient approaches to transfer geospatial information. Road network is the most common linear object in real world. Approximately describe road network information will benefit road map generalization, navigation map production and urban planning. Most of current approaches focused on node diversities and supposed that all the edges are the same, which is inconsistent to real-life condition, and thus show limitations in measuring network information. As real-life traffic flow are directed and of different quantities, the original undirected vector road map was first converted to a directed topographic connectivity map. Then in consideration of preferential attachment in complex network study and rich-club phenomenon in social network, the from and to weights of each edge are assigned. The from weight of a given edge is defined as the connectivity of its end node to the sum of the connectivities of all the neighbors of the from nodes of the edge. After getting the from and to weights of each edge, edge information, node information and the whole network structure information entropies could be obtained based on information theory. The approach has been applied to several 1 square mile road network samples. Results show that information entropies based on edge diversities could successfully describe the structural differences of road networks. This approach is a complementarity to current map information measurements, and can be extended to measure other kinds of geographical objects.

  14. DEFINING THE RELEVANT OUTCOME MEASURES IN MEDICAL DEVICE ASSESSMENTS: AN ANALYSIS OF THE DEFINITION PROCESS IN HEALTH TECHNOLOGY ASSESSMENT.

    Science.gov (United States)

    Jacobs, Esther; Antoine, Sunya-Lee; Prediger, Barbara; Neugebauer, Edmund; Eikermann, Michaela

    2017-01-01

    Defining relevant outcome measures for clinical trials on medical devices (MD) is complex, as there is a large variety of potentially relevant outcomes. The chosen outcomes vary widely across clinical trials making the assessment in evidence syntheses very challenging. The objective is to provide an overview on the current common procedures of health technology assessment (HTA) institutions in defining outcome measures in MD trials. In 2012-14, the Web pages of 126 institutions involved in HTA were searched for methodological manuals written in English or German that describe methods for the predefinition process of outcome measures. Additionally, the institutions were contacted by email. Relevant information was extracted. All process steps were performed independently by two reviewers. Twenty-four manuals and ten responses from the email request were included in the analysis. Overall, 88.5 percent of the institutions describe the type of outcomes that should be considered in detail and 84.6 percent agree that the main focus should be on patient relevant outcomes. Specifically related to MD, information could be obtained in 26 percent of the included manuals and email responses. Eleven percent of the institutions report a particular consideration of MD related outcomes. This detailed analysis on common procedures of HTA institutions in the context of defining relevant outcome measures for the assessment of MD shows that standardized procedures for MD from the perspective of HTA institutions are not widespread. This leads to the question if a homogenous approach should be implemented in the field of HTA on MD.

  15. Survivor-Defined Practice in Domestic Violence Work: Measure Development and Preliminary Evidence of Link to Empowerment.

    Science.gov (United States)

    Goodman, Lisa A; Thomas, Kristie; Cattaneo, Lauren Bennett; Heimel, Deborah; Woulfe, Julie; Chong, Siu Kwan

    2016-01-01

    Survivor-defined practice, characterized by an emphasis on client choice, partnership, and sensitivity to the unique needs, contexts, and coping strategies of individual survivors, is an aspirational goal of the domestic violence (DV) movement, assumed to be a key contributor to empowerment and other positive outcomes among survivors. Despite its central role in DV program philosophy, training, and practice, however, our ability to assess its presence and its presumed link to well-being has been hampered by the absence of a way to measure it from survivors' perspectives. As part of a larger university-community collaboration, this study had two aims: (a) to develop a measure of survivor-defined practice from the perspective of participants, and (b) to assess its relationship to safety-related empowerment after controlling for other contributors to survivor well-being (e.g., financial stability and social support). Results supported the reliability and validity of the Survivor-Defined Practice Scale (SDPS), a nine-item measure that assesses participants' perception of the degree to which their advocates help them achieve goals they set for themselves, facilitate a spirit of partnership, and show sensitivity to their individual needs and styles. The items combined to form one factor indicating that the three theoretical aspects of survivor-defined practice may be different manifestations of one underlying construct. Results also support the hypothesized link between survivor-defined practice and safety-related empowerment. The SDPS offers DV programs a mechanism for process evaluation that is rigorous and rooted in the feminist empowerment philosophy that so many programs espouse. © The Author(s) 2014.

  16. Gas permeation measurement under defined humidity via constant volume/variable pressure method

    KAUST Repository

    Jan Roman, Pauls

    2012-02-01

    Many industrial gas separations in which membrane processes are feasible entail high water vapour contents, as in CO 2-separation from flue gas in carbon capture and storage (CCS), or in biogas/natural gas processing. Studying the effect of water vapour on gas permeability through polymeric membranes is essential for materials design and optimization of these membrane applications. In particular, for amine-based CO 2 selective facilitated transport membranes, water vapour is necessary for carrier-complex formation (Matsuyama et al., 1996; Deng and Hägg, 2010; Liu et al., 2008; Shishatskiy et al., 2010) [1-4]. But also conventional polymeric membrane materials can vary their permeation behaviour due to water-induced swelling (Potreck, 2009) [5]. Here we describe a simple approach to gas permeability measurement in the presence of water vapour, in the form of a modified constant volume/variable pressure method (pressure increase method). © 2011 Elsevier B.V.

  17. Defining and measuring blood donor altruism: a theoretical approach from biology, economics and psychology.

    Science.gov (United States)

    Evans, R; Ferguson, E

    2014-02-01

    While blood donation is traditionally described as a behaviour motivated by pure altruism, the assessment of altruism in the blood donation literature has not been theoretically informed. Drawing on theories of altruism from psychology, economics and evolutionary biology, it is argued that a theoretically derived psychometric assessment of altruism is needed. Such a measure is developed in this study that can be used to help inform both our understanding of the altruistic motives of blood donors and recruitment intervention strategies. A cross-sectional survey (N = 414), with a 1-month behavioural follow-up (time 2, N = 77), was designed to assess theoretically derived constructs from psychological, economic and evolutionary biological theories of altruism. Theory of planned behaviour (TPB) variables and co-operation were also assessed at time 1 and a measure of behavioural co-operation at time 2. Five theoretical dimensions (impure altruism, kinship, self-regarding motives, reluctant altruism and egalitarian warm glow) of altruism were identified through factor analyses. These five altruistic motives differentiated blood donors from non-donors (donors scored higher on impure altruism and reluctant altruism), showed incremental validity over TPB constructs to predict donor intention and predicted future co-operative behaviour. These findings show that altruism in the context of blood donation is multifaceted and complex and, does not reflect pure altruism. This has implication for recruitment campaigns that focus solely on pure altruism. © 2013 The Authors. Vox Sanguinis published by John Wiley & Sons Ltd. on behalf of International Society of Blood Transfusion.

  18. Arrester Resistive Current Measuring System Based on Heterogeneous Network

    Science.gov (United States)

    Zhang, Yun Hua; Li, Zai Lin; Yuan, Feng; Hou Pan, Feng; Guo, Zhan Nan; Han, Yue

    2018-03-01

    Metal Oxide Arrester (MOA) suffers from aging and poor insulation due to long-term impulse voltage and environmental impact, and the value and variation tendency of resistive current can reflect the health conditions of MOA. The common wired MOA detection need to use long cables, which is complicated to operate, and that wireless measurement methods are facing the problems of poor data synchronization and instability. Therefore a novel synchronous measurement system of arrester current resistive based on heterogeneous network is proposed, which simplifies the calculation process and improves synchronization, accuracy and stability and of the measuring system. This system combines LoRa wireless network, high speed wireless personal area network and the process layer communication, and realizes the detection of arrester working condition. Field test data shows that the system has the characteristics of high accuracy, strong anti-interference ability and good synchronization, which plays an important role in ensuring the stable operation of the power grid.

  19. Transaction costs and social networks in productivity measurement

    DEFF Research Database (Denmark)

    Henningsen, Geraldine; Henningsen, Arne; Henning, Christian H. C. A.

    2015-01-01

    and support. Hence, we use measures of a firm’s access to social networks as a proxy for the transaction costs the firm faces. We develop a microeconomic production model that takes into account transaction costs and networks. Using a data set of 384 Polish farms, we empirically estimate this model......We argue that in the presence of transaction costs, observed productivity measures may in many cases understate the true productivity, as production data seldom distinguish between resources entering the production process and resources of a similar type that are sacrificed for transaction costs....... Hence, both the absolute productivity measures and, more importantly, the productivity ranking will be distorted. A major driver of transaction costs is poor access to information and contract enforcement assistance. Social networks often catalyse information exchange as well as generate trust...

  20. Pathloss Measurements and Modeling for UAVs Connected to Cellular Networks

    DEFF Research Database (Denmark)

    Amorim, Rafhael Medeiros de; Mogensen, Preben Elgaard; Sørensen, Troels Bundgaard

    2017-01-01

    . The measurements were conducted in an operating LTE network (850 MHz), using a commercial cell phone, placed inside the frame of the UAV. Trials were conducted for UAV flying at 5 different heights measured above ground level (20, 40, 60, 80 and 100m) and a pathloss regression line was obtained from results. Then......This paper assess field measurements, as part of the investigation of the suitability of cellular networks for providing connectivity to UAVs (unmanned aerial vehicles). Evaluation is done by means of field measurements obtained in a rural environment in Denmark with an airbone UAV......, downlink (DL) SINR levels obtained during flight measurements are also presented. An important result obtained from the measurents reveal that there is a height-related DL SINR degradation. Three main sources of uncertainty on the pathloss model that could be responsible for the SINR degradation are also...

  1. Performance evaluation of multi-stratum resources integration based on network function virtualization in software defined elastic data center optical interconnect.

    Science.gov (United States)

    Yang, Hui; Zhang, Jie; Ji, Yuefeng; Tian, Rui; Han, Jianrui; Lee, Young

    2015-11-30

    Data center interconnect with elastic optical network is a promising scenario to meet the high burstiness and high-bandwidth requirements of data center services. In our previous work, we implemented multi-stratum resilience between IP and elastic optical networks that allows to accommodate data center services. In view of this, this study extends to consider the resource integration by breaking the limit of network device, which can enhance the resource utilization. We propose a novel multi-stratum resources integration (MSRI) architecture based on network function virtualization in software defined elastic data center optical interconnect. A resource integrated mapping (RIM) scheme for MSRI is introduced in the proposed architecture. The MSRI can accommodate the data center services with resources integration when the single function or resource is relatively scarce to provision the services, and enhance globally integrated optimization of optical network and application resources. The overall feasibility and efficiency of the proposed architecture are experimentally verified on the control plane of OpenFlow-based enhanced software defined networking (eSDN) testbed. The performance of RIM scheme under heavy traffic load scenario is also quantitatively evaluated based on MSRI architecture in terms of path blocking probability, provisioning latency and resource utilization, compared with other provisioning schemes.

  2. The new challenges of multiplex networks: Measures and models

    Science.gov (United States)

    Battiston, Federico; Nicosia, Vincenzo; Latora, Vito

    2017-02-01

    What do societies, the Internet, and the human brain have in common? They are all examples of complex relational systems, whose emerging behaviours are largely determined by the non-trivial networks of interactions among their constituents, namely individuals, computers, or neurons, rather than only by the properties of the units themselves. In the last two decades, network scientists have proposed models of increasing complexity to better understand real-world systems. Only recently we have realised that multiplexity, i.e. the coexistence of several types of interactions among the constituents of a complex system, is responsible for substantial qualitative and quantitative differences in the type and variety of behaviours that a complex system can exhibit. As a consequence, multilayer and multiplex networks have become a hot topic in complexity science. Here we provide an overview of some of the measures proposed so far to characterise the structure of multiplex networks, and a selection of models aiming at reproducing those structural properties and quantifying their statistical significance. Focusing on a subset of relevant topics, this brief review is a quite comprehensive introduction to the most basic tools for the analysis of multiplex networks observed in the real-world. The wide applicability of multiplex networks as a framework to model complex systems in different fields, from biology to social sciences, and the colloquial tone of the paper will make it an interesting read for researchers working on both theoretical and experimental analysis of networked systems.

  3. Lightness : a function-virtualizable software defined data center network with all-optical circuit/packet switching

    NARCIS (Netherlands)

    Saridis, G.; Peng, S.; Yan, Y.; Aguado, A.; Guo, B.; Arslan, M.; Jackson, C.; Miao, W.; Calabretta, N.; Agraz, F.; Spadaro, S.; Bernini, G.; Ciulli, N.; Zervas, G.; Nejabati, R.; Simeonidou, D.

    2016-01-01

    Modern high-performance Data Centers are responsible for delivering a huge variety of cloud applications to the end-users, which are increasingly pushing the limits of currently deployed computing and network infrastructure. All-optical dynamic data center network (DCN) architectures are strong

  4. 3D Facial Similarity Measure Based on Geodesic Network and Curvatures

    Directory of Open Access Journals (Sweden)

    Junli Zhao

    2014-01-01

    Full Text Available Automated 3D facial similarity measure is a challenging and valuable research topic in anthropology and computer graphics. It is widely used in various fields, such as criminal investigation, kinship confirmation, and face recognition. This paper proposes a 3D facial similarity measure method based on a combination of geodesic and curvature features. Firstly, a geodesic network is generated for each face with geodesics and iso-geodesics determined and these network points are adopted as the correspondence across face models. Then, four metrics associated with curvatures, that is, the mean curvature, Gaussian curvature, shape index, and curvedness, are computed for each network point by using a weighted average of its neighborhood points. Finally, correlation coefficients according to these metrics are computed, respectively, as the similarity measures between two 3D face models. Experiments of different persons’ 3D facial models and different 3D facial models of the same person are implemented and compared with a subjective face similarity study. The results show that the geodesic network plays an important role in 3D facial similarity measure. The similarity measure defined by shape index is consistent with human’s subjective evaluation basically, and it can measure the 3D face similarity more objectively than the other indices.

  5. Use of artificial neural networks on optical track width measurements

    Science.gov (United States)

    Smith, Richard J.; See, Chung W.; Somekh, Mike G.; Yacoot, Andrew

    2007-08-01

    We have demonstrated recently that, by using an ultrastable optical interferometer together with artificial neural networks (ANNs), track widths down to 60 nm can be measured with a 0.3 NA objective lens. We investigate the effective conditions for training ANNs. Experimental results will be used to show the characteristics of the training samples and the data format of the ANN inputs required to produce suitably trained ANNs. Results obtained with networks measuring double tracks, and classifying different structures, will be presented to illustrate the capability of the technique. We include a discussion on expansion of the application areas of the system, allowing it to be used as a general purpose instrument.

  6. THE MEASUREMENT ELECTROMAGNETIC INTERFERENCE IN THE REVERSE TRACTION NETWORK

    Directory of Open Access Journals (Sweden)

    T. M. Serdiuk

    2009-09-01

    Full Text Available The original automated method of measurement of electrical noise in the return electric-traction network is proposed. It is realized on the base of car-laboratory “Automatics, telemechanics and communication”. The mathematic model of return electric-traction network is developed to scientific bases of automated measurement. It allows us obtaining the mathematic expressions for change of voltage and current harmonics in the rail net and taking into account the inhomogeneity of lines for the following analytic determination of a source of electric noise.

  7. Defining the endpoints: how to measure the efficacy of drugs that are active against central nervous system metastases

    OpenAIRE

    Fabi, Alessandra; Vidiri, Antonello

    2016-01-01

    Brain metastases (BMs) are the most common cause of malignant central nervous system (CNS) tumors in adults. In the recent past, patients with BMs were excluded from clinical trials, but now, with the advent of new biological and immunological drugs, their inclusion is more common. In the last era response and progression criteria used across clinical trials have defined the importance to consider not only measurement changes of brain lesions but also the modification of parameters related to...

  8. Network measurements at the heavy ion synchrotron SIS at GSI

    International Nuclear Information System (INIS)

    Vossbeck, P.; Pschorn, I.; Gebhard, Moritz

    1999-01-01

    The Heavy Ion Synchrotron SIS forms together with the Linear Accelerator UNILAC and the Storage Ring ESR the accelerator complex of the Gesellschaft fuer Schwerionenforschung in Darmstadt. It accelerates heavy ions up to Uranium to 1 GeV/amu. The accelerators and beamlines have been surveyed and aligned using the TASA method. For SIS a network was established in order to survey the synchrotron with the TASA method. Goal of a diploma thesis was to establish an alternative network for a Laser Tracker instrument and to reach error ellipsoids below 30 μm. In this paper a comparison of the two methods is given. Since the Tracker measurements are done automatically only one person is needed. That reduces the man power. Time consumption for both methods is about the same, although much more network points were used with the Laser Tracker method. As a consequence of the larger number of network points the homogeneity of the results is better. (authors)

  9. Dynamical networks: Finding, measuring, and tracking neural population activity using network science

    Directory of Open Access Journals (Sweden)

    Mark D. Humphries

    2017-12-01

    Full Text Available Systems neuroscience is in a headlong rush to record from as many neurons at the same time as possible. As the brain computes and codes using neuron populations, it is hoped these data will uncover the fundamentals of neural computation. But with hundreds, thousands, or more simultaneously recorded neurons come the inescapable problems of visualizing, describing, and quantifying their interactions. Here I argue that network science provides a set of scalable, analytical tools that already solve these problems. By treating neurons as nodes and their interactions as links, a single network can visualize and describe an arbitrarily large recording. I show that with this description we can quantify the effects of manipulating a neural circuit, track changes in population dynamics over time, and quantitatively define theoretical concepts of neural populations such as cell assemblies. Using network science as a core part of analyzing population recordings will thus provide both qualitative and quantitative advances to our understanding of neural computation.

  10. Measuring the construct of executive control in schizophrenia: defining and validating translational animal paradigms for discovery research.

    Science.gov (United States)

    Gilmour, Gary; Arguello, Alexander; Bari, Andrea; Brown, Verity J; Carter, Cameron; Floresco, Stan B; Jentsch, David J; Tait, David S; Young, Jared W; Robbins, Trevor W

    2013-11-01

    Executive control is an aspect of cognitive function known to be impaired in schizophrenia. Previous meetings of the Cognitive Neuroscience Treatment Research to Improve Cognition in Schizophrenia (CNTRICS) group have more precisely defined executive control in terms of two constructs: "rule generation and selection", and "dynamic adjustments of control". Next, human cognitive tasks that may effectively measure performance with regard to these constructs were identified to be developed into practical and reliable measures for use in treatment development. The aim of this round of CNTRICS meetings was to define animal paradigms that have sufficient promise to warrant further investigation for their utility in measuring these constructs. Accordingly, "reversal learning" and the "attentional set-shifting task" were nominated to assess the construct of rule generation and selection, and the "stop signal task" for the construct of dynamic adjustments of control. These tasks are described in more detail here, with a particular focus on their utility for drug discovery efforts. Presently, each assay has strengths and weaknesses with regard to this point and increased emphasis on improving practical aspects of testing, understanding predictive validity, and defining biomarkers of performance represent important objectives in attaining confidence in translational validity here. Crown Copyright © 2012. Published by Elsevier Ltd. All rights reserved.

  11. Measuring Networking as an Outcome Variable in Undergraduate Research Experiences.

    Science.gov (United States)

    Hanauer, David I; Hatfull, Graham

    2015-01-01

    The aim of this paper is to propose, present, and validate a simple survey instrument to measure student conversational networking. The tool consists of five items that cover personal and professional social networks, and its basic principle is the self-reporting of degrees of conversation, with a range of specific discussion partners. The networking instrument was validated in three studies. The basic psychometric characteristics of the scales were established by conducting a factor analysis and evaluating internal consistency using Cronbach's alpha. The second study used a known-groups comparison and involved comparing outcomes for networking scales between two different undergraduate laboratory courses (one involving a specific effort to enhance networking). The final study looked at potential relationships between specific networking items and the established psychosocial variable of project ownership through a series of binary logistic regressions. Overall, the data from the three studies indicate that the networking scales have high internal consistency (α = 0.88), consist of a unitary dimension, can significantly differentiate between research experiences with low and high networking designs, and are related to project ownership scales. The ramifications of the networking instrument for student retention, the enhancement of public scientific literacy, and the differentiation of laboratory courses are discussed. © 2015 D. I. Hanauer and G. Hatfull. CBE—Life Sciences Education © 2015 The American Society for Cell Biology. This article is distributed by The American Society for Cell Biology under license from the author(s). It is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).

  12. Centrality measures and thermodynamic formalism for complex networks.

    Science.gov (United States)

    Delvenne, Jean-Charles; Libert, Anne-Sophie

    2011-04-01

    In the study of small and large networks it is customary to perform a simple random walk where the random walker jumps from one node to one of its neighbors with uniform probability. The properties of this random walk are intimately related to the combinatorial properties of the network. In this paper we propose to use the Ruelle-Bowens random walk instead, whose probability transitions are chosen in order to maximize the entropy rate of the walk on an unweighted graph. If the graph is weighted, then a free energy is optimized instead of the entropy rate. Specifically, we introduce a centrality measure for large networks, which is the stationary distribution attained by the Ruelle-Bowens random walk; we name it entropy rank. We introduce a more general version, which is able to deal with disconnected networks, under the name of free-energy rank. We compare the properties of those centrality measures with the classic PageRank and hyperlink-induced topic search (HITS) on both toy and real-life examples, in particular their robustness to small modifications of the network. We show that our centrality measures are more discriminating than PageRank, since they are able to distinguish clearly pages that PageRank regards as almost equally interesting, and are more sensitive to the medium-scale details of the graph.

  13. Combined techniques for network measurements at accelerator facilities

    International Nuclear Information System (INIS)

    Pschorn, I.

    1999-01-01

    Usually network measurements at GSi (Gesellschaft fur Schwerionen forschung) are carried out by employing the Leica tachymeter TC2002K etc. Due to time constraints and the fact that GSi possesses only one of these selected, high precision total-stations, it was suddenly necessary to think about employing a Laser tracker as the major instrument for a reference network measurement. The idea was to compare the different instruments and to proof if it is possible at all to carry out a precise network measurement using a laser tracker. In the end the SMX Tracker4500 combined with Leica NA3000 for network measurements at GSi, Darmstadt and at BESSY Il, Berlin (both located in Germany) was applied. A few results are shown in the following chapters. A new technology in 3D metrology came up. Some ideas of applying these new tools in the field of accelerator measurements are given. Finally aspects of calibration and checking the performance of the employed high precision instrument are pointed out in this paper. (author)

  14. EIGENVECTOR-BASED CENTRALITY MEASURES FOR TEMPORAL NETWORKS*

    Science.gov (United States)

    TAYLOR, DANE; MYERS, SEAN A.; CLAUSET, AARON; PORTER, MASON A.; MUCHA, PETER J.

    2017-01-01

    Numerous centrality measures have been developed to quantify the importances of nodes in time-independent networks, and many of them can be expressed as the leading eigenvector of some matrix. With the increasing availability of network data that changes in time, it is important to extend such eigenvector-based centrality measures to time-dependent networks. In this paper, we introduce a principled generalization of network centrality measures that is valid for any eigenvector-based centrality. We consider a temporal network with N nodes as a sequence of T layers that describe the network during different time windows, and we couple centrality matrices for the layers into a supra-centrality matrix of size NT × NT whose dominant eigenvector gives the centrality of each node i at each time t. We refer to this eigenvector and its components as a joint centrality, as it reflects the importances of both the node i and the time layer t. We also introduce the concepts of marginal and conditional centralities, which facilitate the study of centrality trajectories over time. We find that the strength of coupling between layers is important for determining multiscale properties of centrality, such as localization phenomena and the time scale of centrality changes. In the strong-coupling regime, we derive expressions for time-averaged centralities, which are given by the zeroth-order terms of a singular perturbation expansion. We also study first-order terms to obtain first-order-mover scores, which concisely describe the magnitude of nodes’ centrality changes over time. As examples, we apply our method to three empirical temporal networks: the United States Ph.D. exchange in mathematics, costarring relationships among top-billed actors during the Golden Age of Hollywood, and citations of decisions from the United States Supreme Court. PMID:29046619

  15. Rapid assessment of agents of biological terrorism: defining the differential diagnosis of inhalational anthrax using electronic communication in a practice-based research network.

    Science.gov (United States)

    Temte, Jonathan L; Anderson, Anna Lisa

    2004-01-01

    Early detection of bioterrorism requires assessment of diagnoses assigned to cases of rare diseases with which clinicians have little experience. In this study, we evaluated the process of defining the differential diagnosis for inhalational anthrax using electronic communication within a practice-based research network (PBRN) and compared the results with those obtained from a nationwide random sample of family physicians with a mailed instrument. We distributed survey instruments by e-mail to 55 physician members of the Wisconsin Research Network (WReN), a regional PBRN. The instruments consisted of 3 case vignettes randomly drawn from a set describing 11 patients with inhalational anthrax, 2 with influenza A, and 1 with Legionella pneumonia. Physicians provided their most likely nonanthrax diagnosis, along with their responses to 4 yes-or-no management questions for each case. Physicians who had not responded at 1 week received a second e-mail with the survey instrument. The comparison group consisted of the nationwide sample of physicians who completed mailed survey instruments. Primary outcome measures were response rate, median response time, and frequencies of diagnostic categories assigned to cases of inhalational anthrax. The PBRN response rate compared favorably with that of the national sample (47.3% vs 37.0%; P = not significant). The median response time for the PBRN was significantly shorter than that for the national sample (2 vs 28 days; P < .001). No significant differences were found between the PBRN and the Midwest subset of the national sample in the frequencies of major diagnostic categories or in case management. Electronic means of creating differential diagnoses for rare infectious diseases of national significance is feasible within PBRNs. Information is much more rapidly acquired and is consistent with that obtained by conventional methods.

  16. Evaluating airline energy efficiency: An integrated approach with Network Epsilon-based Measure and Network Slacks-based Measure

    International Nuclear Information System (INIS)

    Xu, Xin; Cui, Qiang

    2017-01-01

    This paper focuses on evaluating airline energy efficiency, which is firstly divided into four stages: Operations Stage, Fleet Maintenance Stage, Services Stage and Sales Stage. The new four-stage network structure of airline energy efficiency is a modification of existing models. A new approach, integrated with Network Epsilon-based Measure and Network Slacks-based Measure, is applied to assess the overall energy efficiency and divisional efficiency of 19 international airlines from 2008 to 2014. The influencing factors of airline energy efficiency are analyzed through the regression analysis. The results indicate the followings: 1. The integrated model can identify the benchmarking airlines in the overall system and stages. 2. Most airlines' energy efficiencies keep steady during the period, except for some sharply fluctuations. The efficiency decreases mainly centralized in the year 2008–2011, affected by the financial crisis in the USA. 3. The average age of fleet is positively correlated with the overall energy efficiency, and each divisional efficiency has different significant influencing factors. - Highlights: • An integrated approach with Network Epsilon-based Measure and Network Slacks-based Measure is developed. • 19 airlines' energy efficiencies are evaluated. • Garuda Indonesia has the highest overall energy efficiency.

  17. Application of the device based on chirping of optical impulses for management of software-defined networks in dynamic mode

    Science.gov (United States)

    Vinogradova, Irina L.; Khasansin, Vadim R.; Andrianova, Anna V.; Yantilina, Liliya Z.; Vinogradov, Sergey L.

    2016-03-01

    The analysis of the influence of the physical layer concepts in optical networks on the performance of the whole network. It is concluded that the relevance of the search for new means of transmitting information on a physical level. It is proposed to use an optical chirp overhead transmission between controllers SDN. This article is devoted to research of a creation opportunity of optical neural switchboards controlled in addition by submitted optical radiation. It is supposed, that the managing radiation changes a parameter of refraction of optical environment of the device, and with it and length of a wave of information radiation. For the control by last is used multibeam interferometer. The brief estimation of technical aspects of construction of the device is carried out. The principle of using the device to an extensive network. Simulation of network performance parameters.

  18. The French National Network for the Measurement of Environmental Radioactivity

    International Nuclear Information System (INIS)

    Jaunet, P.

    2010-01-01

    After Chernobyl accident in 1986, the government began to implement mechanisms to ensure the quality of measurements of environmental radioactivity and to assure the transparency of information on environmental radioactivity monitoring results. Within this context, the French National Network for the Measurement of Environmental Radioactivity (RNM), is created in 2002 under the Public Health Code. This network is developed under the auspices of ASN in collaboration with IRSN and in partnership with government departments, major nuclear licensees, health agencies and environmental protection associations. In order to centralize information on environmental radioactivity and to provide access to measurement results, a single database that includes an the results of measurements of radioactivity in the environment on the national territory is build and a new web-site www.mesure-radioactivite.fr is launched. It provides quick and easy access to this database. The quality of measurements is performed by a laboratory system through an ASN decision. Novel initiative in Europe, the French National Network for the Measurement of Environmental Radioactivity web-site gives the user keys to understand the measurement results on the radiological state of the environment. The site will be improved over the time taking into account the feedback of the users. (author)

  19. A Typology of Social Capital and Associated Network Measures

    OpenAIRE

    Jackson, Matthew O.

    2017-01-01

    I provide a typology of social capital, breaking it down into seven more fundamental forms of capital: information capital, brokerage capital, coordination and leadership capital, bridging capital, favor capital, reputation capital, and community capital. I discuss how most of these forms of social capital can be identified using different network-based measures.

  20. Measuring Personal Networks and Their Relationship with Scientific Production

    Science.gov (United States)

    Villanueva-Felez, Africa; Molas-Gallart, Jordi; Escribá-Esteve, Alejandro

    2013-01-01

    The analysis of social networks has remained a crucial and yet understudied aspect of the efforts to measure Triple Helix linkages. The Triple Helix model aims to explain, among other aspects of knowledge-based societies, "the current research system in its social context" (Etzkowitz and Leydesdorff 2000:109). This paper develops a novel…

  1. Real-Time Alpine Measurement System Using Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Sami A. Malek

    2017-11-01

    Full Text Available Monitoring the snow pack is crucial for many stakeholders, whether for hydro-power optimization, water management or flood control. Traditional forecasting relies on regression methods, which often results in snow melt runoff predictions of low accuracy in non-average years. Existing ground-based real-time measurement systems do not cover enough physiographic variability and are mostly installed at low elevations. We present the hardware and software design of a state-of-the-art distributed Wireless Sensor Network (WSN-based autonomous measurement system with real-time remote data transmission that gathers data of snow depth, air temperature, air relative humidity, soil moisture, soil temperature, and solar radiation in physiographically representative locations. Elevation, aspect, slope and vegetation are used to select network locations, and distribute sensors throughout a given network location, since they govern snow pack variability at various scales. Three WSNs were installed in the Sierra Nevada of Northern California throughout the North Fork of the Feather River, upstream of the Oroville dam and multiple powerhouses along the river. The WSNs gathered hydrologic variables and network health statistics throughout the 2017 water year, one of northern Sierra’s wettest years on record. These networks leverage an ultra-low-power wireless technology to interconnect their components and offer recovery features, resilience to data loss due to weather and wildlife disturbances and real-time topological visualizations of the network health. Data show considerable spatial variability of snow depth, even within a 1 km 2 network location. Combined with existing systems, these WSNs can better detect precipitation timing and phase in, monitor sub-daily dynamics of infiltration and surface runoff during precipitation or snow melt, and inform hydro power managers about actual ablation and end-of-season date across the landscape.

  2. Real-Time Alpine Measurement System Using Wireless Sensor Networks.

    Science.gov (United States)

    Malek, Sami A; Avanzi, Francesco; Brun-Laguna, Keoma; Maurer, Tessa; Oroza, Carlos A; Hartsough, Peter C; Watteyne, Thomas; Glaser, Steven D

    2017-11-09

    Monitoring the snow pack is crucial for many stakeholders, whether for hydro-power optimization, water management or flood control. Traditional forecasting relies on regression methods, which often results in snow melt runoff predictions of low accuracy in non-average years. Existing ground-based real-time measurement systems do not cover enough physiographic variability and are mostly installed at low elevations. We present the hardware and software design of a state-of-the-art distributed Wireless Sensor Network (WSN)-based autonomous measurement system with real-time remote data transmission that gathers data of snow depth, air temperature, air relative humidity, soil moisture, soil temperature, and solar radiation in physiographically representative locations. Elevation, aspect, slope and vegetation are used to select network locations, and distribute sensors throughout a given network location, since they govern snow pack variability at various scales. Three WSNs were installed in the Sierra Nevada of Northern California throughout the North Fork of the Feather River, upstream of the Oroville dam and multiple powerhouses along the river. The WSNs gathered hydrologic variables and network health statistics throughout the 2017 water year, one of northern Sierra's wettest years on record. These networks leverage an ultra-low-power wireless technology to interconnect their components and offer recovery features, resilience to data loss due to weather and wildlife disturbances and real-time topological visualizations of the network health. Data show considerable spatial variability of snow depth, even within a 1 km 2 network location. Combined with existing systems, these WSNs can better detect precipitation timing and phase in, monitor sub-daily dynamics of infiltration and surface runoff during precipitation or snow melt, and inform hydro power managers about actual ablation and end-of-season date across the landscape.

  3. Internal Interface Diversification as a Security Measure in Sensor Networks

    Directory of Open Access Journals (Sweden)

    Sampsa Rauti

    2018-03-01

    Full Text Available More actuator and sensor devices are connected to the Internet of Things (IoT every day, and the network keeps growing, while software security of the devices is often incomplete. Sensor networks and the IoT in general currently cover a large number of devices with an identical internal interface structure. By diversifying the internal interfaces, the interfaces on each node of the network are made unique, and it is possible to break the software monoculture of easily exploitable identical systems. This paper proposes internal interface diversification as a security measure for sensor networks. We conduct a study on diversifiable internal interfaces in 20 IoT operating systems. We also present two proof-of-concept implementations and perform experiments to gauge the feasibility in the IoT environment. Internal interface diversification has practical limitations, and not all IoT operating systems have that many diversifiable interfaces. However, because of low resource requirements, compatibility with other security measures and wide applicability to several interfaces, we believe internal interface diversification is a promising and effective approach for securing nodes in sensor networks.

  4. A Case Study of Six Sigma Define-Measure-Analyze-Improve-Control (DMAIC Methodology in Garment Sector

    Directory of Open Access Journals (Sweden)

    Abdur Rahman

    2017-12-01

    Full Text Available This paper demonstrates the empirical application of Six Sigma and Define-Measure-Analyze-Improve-Control (DMAIC methodology to reduce product defects within a garments manufacturing organization in Bangladesh which follows the DMAIC methodology to investigate defects, root causes and provide a solution to eliminate these defects. The analysis from employing Six Sigma and DMAIC indicated that the broken stitch and open seam influenced the number of defective products. Design of experiments (DOE and the analysis of variance (ANOVA techniques were combined to statistically determine the correlation of the broken stitch and open seam with defects as well as to define their optimum values needed to eliminate the defects. Thus, a reduction of about 35% in the garments defect was achieved, which helped the organization studied to reduce its defects and thus improve its Sigma level from 1.7 to 3.4.

  5. A measure theoretic approach to traffic flow optimization on networks

    OpenAIRE

    Cacace, Simone; Camilli, Fabio; De Maio, Raul; Tosin, Andrea

    2018-01-01

    We consider a class of optimal control problems for measure-valued nonlinear transport equations describing traffic flow problems on networks. The objective isto minimise/maximise macroscopic quantities, such as traffic volume or average speed,controlling few agents, for example smart traffic lights and automated cars. The measuretheoretic approach allows to study in a same setting local and nonlocal drivers interactionsand to consider the control variables as additional measures interacting ...

  6. Experimental demonstration of an OpenFlow based software-defined optical network employing packet, fixed and flexible DWDM grid technologies on an international multi-domain testbed.

    Science.gov (United States)

    Channegowda, M; Nejabati, R; Rashidi Fard, M; Peng, S; Amaya, N; Zervas, G; Simeonidou, D; Vilalta, R; Casellas, R; Martínez, R; Muñoz, R; Liu, L; Tsuritani, T; Morita, I; Autenrieth, A; Elbers, J P; Kostecki, P; Kaczmarek, P

    2013-03-11

    Software defined networking (SDN) and flexible grid optical transport technology are two key technologies that allow network operators to customize their infrastructure based on application requirements and therefore minimizing the extra capital and operational costs required for hosting new applications. In this paper, for the first time we report on design, implementation & demonstration of a novel OpenFlow based SDN unified control plane allowing seamless operation across heterogeneous state-of-the-art optical and packet transport domains. We verify and experimentally evaluate OpenFlow protocol extensions for flexible DWDM grid transport technology along with its integration with fixed DWDM grid and layer-2 packet switching.

  7. The design of nuclear radiation measuring instrument of embedded network

    International Nuclear Information System (INIS)

    Zhang Huaiqiang; Ge Liangquan; Xiong Shengqing

    2009-01-01

    The design and realization of nuclear radiation measuring instrument is introduced. Due to the current nuclear instrument often used serial interface to communicate the PC, it is widely used for simple design and easy operation. However, as the demand of remote data acquisition and the call of sharing resources, the design of embedded the TCP/IP protocol stack into MCU, it may send the nuclear signal in Internet. Some devices that link each other with the network can be networked. The design is not only realizing remote data acquisition and sharing resources, but also reducing costs and improving the maintainability of the system. (authors)

  8. 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.

  9. Joint flow routing-scheduling for energy efficient software defined data center networks : A prototype of energy-aware network management platform

    NARCIS (Netherlands)

    Zhu, H.; Liao, X.; de Laat, C.; Grosso, P.

    Data centers are a cost-effective infrastructure for hosting Cloud and Grid applications, but they do incur tremendous energy cost and CO2 emissions. Today's data center network architectures such as Fat-tree and BCube are over-provisioned to guarantee large network capacity and meet peak

  10. Measuring and evaluating energy consumption in street lighting networks

    International Nuclear Information System (INIS)

    Janiga, P.; Gasparovsky, D.

    2012-01-01

    Smart metering and smart grid are incoming technologies that provide new opportunities in various fields. In connection with the issue of evaluation of the energy aspects of public lighting networks opens up the possibility of evaluating and measuring consumption. Based on the obtained values would be possible to determine energy consumption of lighting systems. This obtained value could serve as a basis for comparing the relevant networks and thus the optimality assessment of lighting designs. Currently, the measure placed in the switchboard of public lighting. If we have considered sections parametramim same lighting, it is necessary to obtain more value from the measured or determined to assess the consumption of time. Proposal of such methods is still under construction but the basic methods have already been outlined. (Authors)

  11. AziSA: an architecture for underground measurement and control networks - 2nd International Conference on Wireless Communications...

    CSIR Research Space (South Africa)

    Stewart, R

    2008-08-01

    Full Text Available AziSA is an architecture for measurement and control networks that can be used to collect, store and facilitate the analysis of data from challenging underground environments. AziSA defines four node classes, two (Classes Four and Three...

  12. A discussion of techniques used in defining the Interactive Measurement Evaluation and Control System at Rocky Flats

    International Nuclear Information System (INIS)

    Greer, B.K.; Hunt, V.; Schweitzer, M.F.

    1983-01-01

    This paper describes both the general methodology used to study the current needs for a measurement control and evaluation system at Rocky Flats Plant and the recommendations for implementation into the Interactive Measurement Evaluation and Control System (IMECS). The study resulted in a clear assessment of the current system and recommendations for the system which will be its replacement. To arrive at the recommendations, the authors used a formal analysis approach that is based on an in-depth study of the measurement evaluation and control problems and user needs. The problems and needs were defined by interviews with present and potential users of this kind of system throughout the nuclear industry. Some of the recommendations are to provide: timely sample measurement feedback; representative measurement error estimates; a history data base of sample measurements To meet the user needs, the new system will: be interactive with user selection menus; use standards which cover the range of application; facilitate historical analysis of sample data and bookkeeping. The implementation of this program is projected to be more cost effective than the current program. Also included are the authors' recommendations to those involved in the design of a system of similar large magnitude

  13. Dual Cross-Linked Biofunctional and Self-Healing Networks to Generate User-Defined Modular Gradient Hydrogel Constructs.

    Science.gov (United States)

    Wei, Zhao; Lewis, Daniel M; Xu, Yu; Gerecht, Sharon

    2017-08-01

    Gradient hydrogels have been developed to mimic the spatiotemporal differences of multiple gradient cues in tissues. Current approaches used to generate such hydrogels are restricted to a single gradient shape and distribution. Here, a hydrogel is designed that includes two chemical cross-linking networks, biofunctional, and self-healing networks, enabling the customizable formation of modular gradient hydrogel construct with various gradient distributions and flexible shapes. The biofunctional networks are formed via Michael addition between the acrylates of oxidized acrylated hyaluronic acid (OAHA) and the dithiol of matrix metalloproteinase (MMP)-sensitive cross-linker and RGD peptides. The self-healing networks are formed via dynamic Schiff base reaction between N-carboxyethyl chitosan (CEC) and OAHA, which drives the modular gradient units to self-heal into an integral modular gradient hydrogel. The CEC-OAHA-MMP hydrogel exhibits excellent flowability at 37 °C under shear stress, enabling its injection to generate gradient distributions and shapes. Furthermore, encapsulated sarcoma cells respond to the gradient cues of RGD peptides and MMP-sensitive cross-linkers in the hydrogel. With these superior properties, the dual cross-linked CEC-OAHA-MMP hydrogel holds significant potential for generating customizable gradient hydrogel constructs, to study and guide cellular responses to their microenvironment such as in tumor mimicking, tissue engineering, and stem cell differentiation and morphogenesis. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. 17 CFR 247.700 - Defined terms relating to the networking exception from the definition of “broker.”

    Science.gov (United States)

    2010-04-01

    ... the average of the minimum and maximum hourly wage established by the bank for the current or prior... networking exception from the definition of âbroker.â 247.700 Section 247.700 Commodity and Securities Exchanges SECURITIES AND EXCHANGE COMMISSION (CONTINUED) REGULATION R-EXEMPTIONS AND DEFINITIONS RELATED TO...

  15. Dynamic routing and spectrum assignment based on multilayer virtual topology and ant colony optimization in elastic software-defined optical networks

    Science.gov (United States)

    Wang, Fu; Liu, Bo; Zhang, Lijia; Zhang, Qi; Tian, Qinghua; Tian, Feng; Rao, Lan; Xin, Xiangjun

    2017-07-01

    Elastic software-defined optical networks greatly improve the flexibility of the optical switching network while it has brought challenges to the routing and spectrum assignment (RSA). A multilayer virtual topology model is proposed to solve RSA problems. Two RSA algorithms based on the virtual topology are proposed, which are the ant colony optimization (ACO) algorithm of minimum consecutiveness loss and the ACO algorithm of maximum spectrum consecutiveness. Due to the computing power of the control layer in the software-defined network, the routing algorithm avoids the frequent link-state information between routers. Based on the effect of the spectrum consecutiveness loss on the pheromone in the ACO, the path and spectrum of the minimal impact on the network are selected for the service request. The proposed algorithms have been compared with other algorithms. The results show that the proposed algorithms can reduce the blocking rate by at least 5% and perform better in spectrum efficiency. Moreover, the proposed algorithms can effectively decrease spectrum fragmentation and enhance available spectrum consecutiveness.

  16. Measuring Social Capital in Virtual Social Networks; Introducing Workable Indices

    Directory of Open Access Journals (Sweden)

    Hamid Abdollahian

    2013-12-01

    Full Text Available This paper will attempt to offer a set of indicators that together construct a model which will help to measure social capital among users of social networks. The world is now experiencing some new changes that are affecting conceptual equations in social sciences, two of which are of our concern here: 1- the concept of social capital that has opened its way into epistemological basis of social sciences, and; 2- the world has welcomed the birth and development of social networks in our daily life, affecting many aspects of social actions. There is Facebook from among a handful of social networks that has reached the threshold of international networking capacity with roughly one billion users. We will use Robert Putnam's theory of social capital alongside Frank's methodological innovation regarding measuring tools of social capital in order to create a marriage between these two as well as to address a yet more problematizing issue, i.e., how to measure social capital of the Facebook users. Accordingly the paper will focus on Facebook as the field of research and will introduce triangulation approach that we used in order to come up with the set of indicators. Participatory observation and online survey were used as constructing elements of triangulation approach so to generate the necessary data for the above purpose. At first, we used participatory observation through which 14 targeted samples were selected and whatever they had in their profile in Facebook were collected and analyzed. This analysis helped us to construct our questionnaire which was launched through Google docs. In the end, some 218 respondent returned their completed questionnaires. The final stage of analysis consisted of finding out how we can use the results to offer a new tool for measuring social capital of Facebook users. The research findings indicated that there are 10 indicators which should be put together if social capital is to be properly measured.

  17. The vexing problem of defining the meaning, role and measurement of values in treatment decision-making.

    Science.gov (United States)

    Charles, Cathy; Gafni, Amiram

    2014-03-01

    Two international movements, evidence-based medicine (EBM) and shared decision-making (SDM) have grappled for some time with issues related to defining the meaning, role and measurement of values/preferences in their respective models of treatment decision-making. In this article, we identify and describe unresolved problems in the way that each movement addresses these issues. The starting point for this discussion is that at least two essential ingredients are needed for treatment decision-making: research information about treatment options and their potential benefits and risks; and the values/preferences of participants in the decision-making process. Both the EBM and SDM movements have encountered difficulties in defining the meaning, role and measurement of values/preferences in treatment decision-making. In the EBM model of practice, there is no clear and consistent definition of patient values/preferences and no guidance is provided on how to integrate these into an EBM model of practice. Methods advocated to measure patient values are also problematic. Within the SDM movement, patient values/preferences tend to be defined and measured in a restrictive and reductionist way as patient preferences for treatment options or attributes of options, while broader underlying value structures are ignored. In both models of practice, the meaning and expected role of physician values in decision-making are unclear. Values clarification exercises embedded in patient decision aids are suggested by SDM advocates to identify and communicate patient values/preferences for different treatment outcomes. Such exercises have the potential to impose a particular decision-making theory and/or process onto patients, which can change the way they think about and process information, potentially impeding them from making decisions that are consistent with their true values. The tasks of clarifying the meaning, role and measurement of values/preferences in treatment decision

  18. What is culture in «cultural economy»? Defining culture to create measurable models in cultural economy

    Directory of Open Access Journals (Sweden)

    Aníbal Monasterio Astobiza

    2017-07-01

    Full Text Available The idea of culture is somewhat vague and ambiguous for the formal goals of economics. The aim of this paper is to define the notion of culture better so as to help build economic explanations based on culture and therefore to measure its impact in every activity or beliefs associated with culture. To define culture according to the canonical evolutionary definition, it is any kind of ritualised behaviour that becomes meaningful for a group and that remains more or less constant and is transmitted down through the generations. Economic institutions are founded, implicitly or explicitly, on a worldview of how humans function; culture is an essential part of understanding us as humans, making it necessary to describe what we understand by culture correctly. In this paper we review the literature on evolutionary anthropology and psychology dealing with the concept of culture to warn that economic modelling ignores intangible benefits of culture rendering economics unable to measure certain cultural items in the digital consumer society.

  19. Measuring large-scale social networks with high resolution.

    Directory of Open Access Journals (Sweden)

    Arkadiusz Stopczynski

    Full Text Available This paper describes the deployment of a large-scale study designed to measure human interactions across a variety of communication channels, with high temporal resolution and spanning multiple years-the Copenhagen Networks Study. Specifically, we collect data on face-to-face interactions, telecommunication, social networks, location, and background information (personality, demographics, health, politics for a densely connected population of 1000 individuals, using state-of-the-art smartphones as social sensors. Here we provide an overview of the related work and describe the motivation and research agenda driving the study. Additionally, the paper details the data-types measured, and the technical infrastructure in terms of both backend and phone software, as well as an outline of the deployment procedures. We document the participant privacy procedures and their underlying principles. The paper is concluded with early results from data analysis, illustrating the importance of multi-channel high-resolution approach to data collection.

  20. Integration of neural networks with fuzzy reasoning for measuring operational parameters in a nuclear reactor

    International Nuclear Information System (INIS)

    Ikonomopoulos, A.; Tsoukalas, L.H.

    1993-01-01

    A novel approach is described for measuring variables with operational significance in a complex system such as a nuclear reactor. The methodology is based on the integration of artificial neural networks with fuzzy reasoning. Neural networks are used to map dynamic time series to a set of user-defined linguistic labels called fuzzy values. The process takes place in a manner analogous to that of measurement. Hence, the entire procedure is referred to as virtual measurement and its software implementation as a virtual measuring device. An optimization algorithm based on information criteria and fuzzy algebra augments the process and assists in the identification of different states of the monitored parameter. The proposed technique is applied for monitoring parameters such as performance, valve position, transient type, and reactivity. The results obtained from the application of the neural network-fuzzy reasoning integration in a high power research reactor clearly demonstrate the excellent tolerance of the virtual measuring device to faulty signals as well as its ability to accommodate noisy inputs

  1. Benchmarking Measures of Network Controllability on Canonical Graph Models

    Science.gov (United States)

    Wu-Yan, Elena; Betzel, Richard F.; Tang, Evelyn; Gu, Shi; Pasqualetti, Fabio; Bassett, Danielle S.

    2018-03-01

    The control of networked dynamical systems opens the possibility for new discoveries and therapies in systems biology and neuroscience. Recent theoretical advances provide candidate mechanisms by which a system can be driven from one pre-specified state to another, and computational approaches provide tools to test those mechanisms in real-world systems. Despite already having been applied to study network systems in biology and neuroscience, the practical performance of these tools and associated measures on simple networks with pre-specified structure has yet to be assessed. Here, we study the behavior of four control metrics (global, average, modal, and boundary controllability) on eight canonical graphs (including Erdős-Rényi, regular, small-world, random geometric, Barábasi-Albert preferential attachment, and several modular networks) with different edge weighting schemes (Gaussian, power-law, and two nonparametric distributions from brain networks, as examples of real-world systems). We observe that differences in global controllability across graph models are more salient when edge weight distributions are heavy-tailed as opposed to normal. In contrast, differences in average, modal, and boundary controllability across graph models (as well as across nodes in the graph) are more salient when edge weight distributions are less heavy-tailed. Across graph models and edge weighting schemes, average and modal controllability are negatively correlated with one another across nodes; yet, across graph instances, the relation between average and modal controllability can be positive, negative, or nonsignificant. Collectively, these findings demonstrate that controllability statistics (and their relations) differ across graphs with different topologies and that these differences can be muted or accentuated by differences in the edge weight distributions. More generally, our numerical studies motivate future analytical efforts to better understand the mathematical

  2. Skill networks and measures of complex human capital.

    Science.gov (United States)

    Anderson, Katharine A

    2017-11-28

    We propose a network-based method for measuring worker skills. We illustrate the method using data from an online freelance website. Using the tools of network analysis, we divide skills into endogenous categories based on their relationship with other skills in the market. Workers who specialize in these different areas earn dramatically different wages. We then show that, in this market, network-based measures of human capital provide additional insight into wages beyond traditional measures. In particular, we show that workers with diverse skills earn higher wages than those with more specialized skills. Moreover, we can distinguish between two different types of workers benefiting from skill diversity: jacks-of-all-trades, whose skills can be applied independently on a wide range of jobs, and synergistic workers, whose skills are useful in combination and fill a hole in the labor market. On average, workers whose skills are synergistic earn more than jacks-of-all-trades. Copyright © 2017 the Author(s). Published by PNAS.

  3. Use of Time-Frequency Analysis and Neural Networks for Mode Identification in a Wireless Software-Defined Radio Approach

    Directory of Open Access Journals (Sweden)

    Matteo Gandetto

    2004-09-01

    Full Text Available The use of time-frequency distributions is proposed as a nonlinear signal processing technique that is combined with a pattern recognition approach to identify superimposed transmission modes in a reconfigurable wireless terminal based on software-defined radio techniques. In particular, a software-defined radio receiver is described aiming at the identification of two coexistent communication modes: frequency hopping code division multiple access and direct sequence code division multiple access. As a case study, two standards, based on the previous modes and operating in the same band (industrial, scientific, and medical, are considered: IEEE WLAN 802.11b (direct sequence and Bluetooth (frequency hopping. Neural classifiers are used to obtain identification results. A comparison between two different neural classifiers is made in terms of relative error frequency.

  4. A Bayesian Retrieval of Greenland Ice Sheet Internal Temperature from Ultra-wideband Software-defined Microwave Radiometer (UWBRAD) Measurements

    Science.gov (United States)

    Duan, Y.; Durand, M. T.; Jezek, K. C.; Yardim, C.; Bringer, A.; Aksoy, M.; Johnson, J. T.

    2017-12-01

    The ultra-wideband software-defined microwave radiometer (UWBRAD) is designed to provide ice sheet internal temperature product via measuring low frequency microwave emission. Twelve channels ranging from 0.5 to 2.0 GHz are covered by the instrument. A Greenland air-borne demonstration was demonstrated in September 2016, provided first demonstration of Ultra-wideband radiometer observations of geophysical scenes, including ice sheets. Another flight is planned for September 2017 for acquiring measurements in central ice sheet. A Bayesian framework is designed to retrieve the ice sheet internal temperature from simulated UWBRAD brightness temperature (Tb) measurements over Greenland flight path with limited prior information of the ground. A 1-D heat-flow model, the Robin Model, was used to model the ice sheet internal temperature profile with ground information. Synthetic UWBRAD Tb observations was generated via the partially coherent radiation transfer model, which utilizes the Robin model temperature profile and an exponential fit of ice density from Borehole measurement as input, and corrupted with noise. The effective surface temperature, geothermal heat flux, the variance of upper layer ice density, and the variance of fine scale density variation at deeper ice sheet were treated as unknown variables within the retrieval framework. Each parameter is defined with its possible range and set to be uniformly distributed. The Markov Chain Monte Carlo (MCMC) approach is applied to make the unknown parameters randomly walk in the parameter space. We investigate whether the variables can be improved over priors using the MCMC approach and contribute to the temperature retrieval theoretically. UWBRAD measurements near camp century from 2016 was also treated with the MCMC to examine the framework with scattering effect. The fine scale density fluctuation is an important parameter. It is the most sensitive yet highly unknown parameter in the estimation framework

  5. Greenhouse gas measurements from a UK network of tall towers: technical description and first results

    Science.gov (United States)

    Stanley, Kieran M.; Grant, Aoife; O'Doherty, Simon; Young, Dickon; Manning, Alistair J.; Stavert, Ann R.; Spain, T. Gerard; Salameh, Peter K.; Harth, Christina M.; Simmonds, Peter G.; Sturges, William T.; Oram, David E.; Derwent, Richard G.

    2018-03-01

    A network of three tall tower measurement stations was set up in 2012 across the United Kingdom to expand measurements made at the long-term background northern hemispheric site, Mace Head, Ireland. Reliable and precise in situ greenhouse gas (GHG) analysis systems were developed and deployed at three sites in the UK with automated instrumentation measuring a suite of GHGs. The UK Deriving Emissions linked to Climate Change (UK DECC) network uses tall (165-230 m) open-lattice telecommunications towers, which provide a convenient platform for boundary layer trace gas sampling. In this paper we describe the automated measurement system and first results from the UK DECC network for CO2, CH4, N2O, SF6, CO and H2. CO2 and CH4 are measured at all of the UK DECC sites by cavity ring-down spectroscopy (CRDS) with multiple inlet heights at two of the three tall tower sites to assess for boundary layer stratification. The short-term precisions (1σ on 1 min means) of CRDS measurements at background mole fractions for January 2012 to September 2015 is sampling temperatures. Automated alerts are generated and emailed to site operators when instrumental parameters are not within defined set ranges. Automated instrument shutdowns occur for critical errors such as carrier gas flow rate deviations. Results from the network give good spatial and temporal coverage of atmospheric mixing ratios within the UK since early 2012. Results also show that all measured GHGs are increasing in mole fraction over the selected reporting period and, except for SF6, exhibit a seasonal trend. CO2 and CH4 also show strong diurnal cycles, with night-time maxima and daytime minima in mole fractions.

  6. Reverse engineering of modified genes by Bayesian network analysis defines molecular determinants critical to the development of glioblastoma.

    Directory of Open Access Journals (Sweden)

    Brian W Kunkle

    Full Text Available In this study we have identified key genes that are critical in development of astrocytic tumors. Meta-analysis of microarray studies which compared normal tissue to astrocytoma revealed a set of 646 differentially expressed genes in the majority of astrocytoma. Reverse engineering of these 646 genes using Bayesian network analysis produced a gene network for each grade of astrocytoma (Grade I-IV, and 'key genes' within each grade were identified. Genes found to be most influential to development of the highest grade of astrocytoma, Glioblastoma multiforme were: COL4A1, EGFR, BTF3, MPP2, RAB31, CDK4, CD99, ANXA2, TOP2A, and SERBP1. All of these genes were up-regulated, except MPP2 (down regulated. These 10 genes were able to predict tumor status with 96-100% confidence when using logistic regression, cross validation, and the support vector machine analysis. Markov genes interact with NFkβ, ERK, MAPK, VEGF, growth hormone and collagen to produce a network whose top biological functions are cancer, neurological disease, and cellular movement. Three of the 10 genes - EGFR, COL4A1, and CDK4, in particular, seemed to be potential 'hubs of activity'. Modified expression of these 10 Markov Blanket genes increases lifetime risk of developing glioblastoma compared to the normal population. The glioblastoma risk estimates were dramatically increased with joint effects of 4 or more than 4 Markov Blanket genes. Joint interaction effects of 4, 5, 6, 7, 8, 9 or 10 Markov Blanket genes produced 9, 13, 20.9, 26.7, 52.8, 53.2, 78.1 or 85.9%, respectively, increase in lifetime risk of developing glioblastoma compared to normal population. In summary, it appears that modified expression of several 'key genes' may be required for the development of glioblastoma. Further studies are needed to validate these 'key genes' as useful tools for early detection and novel therapeutic options for these tumors.

  7. Surface Charge Measurement of SonoVue, Definity and Optison: A Comparison of Laser Doppler Electrophoresis and Micro-Electrophoresis.

    Science.gov (United States)

    Ja'afar, Fairuzeta; Leow, Chee Hau; Garbin, Valeria; Sennoga, Charles A; Tang, Meng-Xing; Seddon, John M

    2015-11-01

    Microbubble (MB) contrast-enhanced ultrasonography is a promising tool for targeted molecular imaging. It is important to determine the MB surface charge accurately as it affects the MB interactions with cell membranes. In this article, we report the surface charge measurement of SonoVue, Definity and Optison. We compare the performance of the widely used laser Doppler electrophoresis with an in-house micro-electrophoresis system. By optically tracking MB electrophoretic velocity in a microchannel, we determined the zeta potentials of MB samples. Using micro-electrophoresis, we obtained zeta potential values for SonoVue, Definity and Optison of -28.3, -4.2 and -9.5 mV, with relative standard deviations of 5%, 48% and 8%, respectively. In comparison, laser Doppler electrophoresis gave -8.7, +0.7 and +15.8 mV with relative standard deviations of 330%, 29,000% and 130%, respectively. We found that the reliability of laser Doppler electrophoresis is compromised by MB buoyancy. Micro-electrophoresis determined zeta potential values with a 10-fold improvement in relative standard deviation. Copyright © 2015 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

  8. Measuring the degree of integration for an integrated service network

    Directory of Open Access Journals (Sweden)

    Chenglin Ye

    2012-09-01

    Full Text Available Background: Integration involves the coordination of services provided by autonomous agencies and improves the organization and delivery of multiple services for target patients. Current measures generally do not distinguish between agencies' perception and expectation. We propose a method for quantifying the agencies' service integration. Using the data from the Children's Treatment Network (CTN, we aimed to measure the degree of integration for the CTN agencies in York and Simcoe.  Theory and Methods: We quantified the integration by the agreement between perceived and expected levels of involvement and calculated four scores from different perspectives for each agency. We used the average score to measure the global network integration and examined the sensitivity of the global score.  Results: Most agencies' integration scores were less than 65%. As measured by the agreement between every other agency's perception and expectation, the overall integration of CTN in Simcoe and York was 44% (95% CI: 39% - 49% and 52% (95% CI: 48% - 56%, respectively. The sensitivity analysis showed that the global scores were robust.  Conclusion: Our method extends existing measures of integration and possesses a good extent of validity. We can also apply the method in monitoring improvement and linking integration with other outcomes.

  9. Measuring the degree of integration for an integrated service network

    Directory of Open Access Journals (Sweden)

    Chenglin Ye

    2012-09-01

    Full Text Available Background: Integration involves the coordination of services provided by autonomous agencies and improves the organization and delivery of multiple services for target patients. Current measures generally do not distinguish between agencies' perception and expectation. We propose a method for quantifying the agencies' service integration. Using the data from the Children's Treatment Network (CTN, we aimed to measure the degree of integration for the CTN agencies in York and Simcoe. Theory and Methods: We quantified the integration by the agreement between perceived and expected levels of involvement and calculated four scores from different perspectives for each agency. We used the average score to measure the global network integration and examined the sensitivity of the global score. Results: Most agencies' integration scores were less than 65%. As measured by the agreement between every other agency's perception and expectation, the overall integration of CTN in Simcoe and York was 44% (95% CI: 39% - 49% and 52% (95% CI: 48% - 56%, respectively. The sensitivity analysis showed that the global scores were robust. Conclusion: Our method extends existing measures of integration and possesses a good extent of validity. We can also apply the method in monitoring improvement and linking integration with other outcomes. 

  10. Measurement of agricultural parameters using wireless sensor network (WSN)

    Science.gov (United States)

    Guaña-Moya, Javier; Sánchez-Almeida, Tarquino; Salgado-Reyes, Nelson

    2018-04-01

    The technological advances have allowed to create new applications in telecommunications, applying low power and reduced costs in their equipment, thus achieving the evolution of new wireless networks or also denominated Wireless Sensor Network. These technologies allow the generation of measurements and analysis of environmental parameter data and soil. Precision agriculture requires parameters for the improvement of production, obtained through WSN technologies. This research analyzes the climatic requirements and soil parameters in a rose plantation in a greenhouse at an altitude of 3,100 meters above sea level. In the present investigation, maximum parameters were obtained in the production of roses, which are in the optimum range of production, whereas the minimum parameters of temperature, humidity and luminosity, evidenced that these parameters can damage the plants, since temperatures less than 10 °C slow down the growth of the plant and allow the proliferation of diseases and fungi.

  11. Reverse Engineering of Modified Genes by Bayesian Network Analysis Defines Molecular Determinants Critical to the Development of Glioblastoma

    Science.gov (United States)

    Kunkle, Brian W.; Yoo, Changwon; Roy, Deodutta

    2013-01-01

    In this study we have identified key genes that are critical in development of astrocytic tumors. Meta-analysis of microarray studies which compared normal tissue to astrocytoma revealed a set of 646 differentially expressed genes in the majority of astrocytoma. Reverse engineering of these 646 genes using Bayesian network analysis produced a gene network for each grade of astrocytoma (Grade I–IV), and ‘key genes’ within each grade were identified. Genes found to be most influential to development of the highest grade of astrocytoma, Glioblastoma multiforme were: COL4A1, EGFR, BTF3, MPP2, RAB31, CDK4, CD99, ANXA2, TOP2A, and SERBP1. All of these genes were up-regulated, except MPP2 (down regulated). These 10 genes were able to predict tumor status with 96–100% confidence when using logistic regression, cross validation, and the support vector machine analysis. Markov genes interact with NFkβ, ERK, MAPK, VEGF, growth hormone and collagen to produce a network whose top biological functions are cancer, neurological disease, and cellular movement. Three of the 10 genes - EGFR, COL4A1, and CDK4, in particular, seemed to be potential ‘hubs of activity’. Modified expression of these 10 Markov Blanket genes increases lifetime risk of developing glioblastoma compared to the normal population. The glioblastoma risk estimates were dramatically increased with joint effects of 4 or more than 4 Markov Blanket genes. Joint interaction effects of 4, 5, 6, 7, 8, 9 or 10 Markov Blanket genes produced 9, 13, 20.9, 26.7, 52.8, 53.2, 78.1 or 85.9%, respectively, increase in lifetime risk of developing glioblastoma compared to normal population. In summary, it appears that modified expression of several ‘key genes’ may be required for the development of glioblastoma. Further studies are needed to validate these ‘key genes’ as useful tools for early detection and novel therapeutic options for these tumors. PMID:23737970

  12. A defined network of fast-spiking interneurons in orbitofrontal cortex: responses to behavioral contingencies and ketamine administration

    Directory of Open Access Journals (Sweden)

    Michael C Quirk

    2009-11-01

    Full Text Available Orbitofrontal cortex (OFC is a region of prefrontal cortex implicated in the motivational control of behavior and in related abnormalities seen in psychosis and depression. It has been hypothesized that a critical mechanism in these disorders is the dysfunction of GABAergic interneurons that normally regulate prefrontal information processing. Here, we studied a subclass of interneurons isolated in rat OFC using extracellular waveform and spike train analysis. During performance of a goal-directed behavioral task, the firing of this class of putative fast-spiking (FS interneurons showed robust temporal correlations indicative of a functionally coherent network. FS cell activity also co-varied with behavioral response latency, a key indicator of motivational state. Systemic administration of ketamine, a drug that can mimic psychosis, preferentially inhibited this cell class. Together, these results support the idea that OFC-FS interneurons form a critical link in the regulation of motivation by prefrontal circuits during normal and abnormal brain and behavioral states.

  13. Defining a mismatch: differences in usage of social networking sites between medical students and the faculty who teach them.

    Science.gov (United States)

    Brisson, Gregory E; Fisher, Matthew J; LaBelle, Mark W; Kozmic, Sarah E

    2015-01-01

    Use of social networking sites (SNS) by medical students is increasing, and some students lack awareness of pitfalls arising from the intersection of social networking and medicine. Many institutions have developed guidelines on using SNS, but they are insufficient for students. Educators need new methods to train students on the appropriate use of this technology, but more information is needed before implementing change. Differences in SNS usage between students and faculty were examined. The goal was to evaluate four content areas: SNS usage patterns, attitudes regarding activity on SNS, experience with patient interactions online, and awareness of institutional guidelines on use of SNS. A cross-sectional survey took place at Feinberg School of Medicine, Northwestern University, in 2012. Participants included all students and a cohort of faculty who teach them in a class on professionalism. The response rate was 42% by students (300/711) and 78% by faculty (31/40). Of the students, 94% use SNS, compared to 48% of faculty. Students were more likely than faculty to display content they would not want patients to see (57% vs. 27%), report seeing inappropriate content on colleagues' SNS profiles (64% vs. 42%), and ignore harmful postings by colleagues (25% vs. 7%). Faculty were more likely than students to have been approached by patients on SNS (53% vs. 3%). Most participants were unlikely to conduct Internet searches on patients. Students are more likely than faculty to use SNS and use it very differently than faculty. Students would benefit from training on appropriate use of SNS. Topics that should be addressed include editing one's online presence, managing friend requests from patients, dealing with colleagues who post harmful content, conducting Internet searches on patients, and discussion of boundaries to identify potential harms associated with SNS usage. Differences in usage between students and faculty raise questions if faculty are well suited to

  14. Temporal network based analysis of cell specific vein graft transcriptome defines key pathways and hub genes in implantation injury.

    Directory of Open Access Journals (Sweden)

    Manoj Bhasin

    Full Text Available Vein graft failure occurs between 1 and 6 months after implantation due to obstructive intimal hyperplasia, related in part to implantation injury. The cell-specific and temporal response of the transcriptome to vein graft implantation injury was determined by transcriptional profiling of laser capture microdissected endothelial cells (EC and medial smooth muscle cells (SMC from canine vein grafts, 2 hours (H to 30 days (D following surgery. Our results demonstrate a robust genomic response beginning at 2 H, peaking at 12-24 H, declining by 7 D, and resolving by 30 D. Gene ontology and pathway analyses of differentially expressed genes indicated that implantation injury affects inflammatory and immune responses, apoptosis, mitosis, and extracellular matrix reorganization in both cell types. Through backpropagation an integrated network was built, starting with genes differentially expressed at 30 D, followed by adding upstream interactive genes from each prior time-point. This identified significant enrichment of IL-6, IL-8, NF-κB, dendritic cell maturation, glucocorticoid receptor, and Triggering Receptor Expressed on Myeloid Cells (TREM-1 signaling, as well as PPARα activation pathways in graft EC and SMC. Interactive network-based analyses identified IL-6, IL-8, IL-1α, and Insulin Receptor (INSR as focus hub genes within these pathways. Real-time PCR was used for the validation of two of these genes: IL-6 and IL-8, in addition to Collagen 11A1 (COL11A1, a cornerstone of the backpropagation. In conclusion, these results establish causality relationships clarifying the pathogenesis of vein graft implantation injury, and identifying novel targets for its prevention.

  15. Reactor building indoor wireless network channel quality estimation using RSSI measurement of wireless sensor network

    International Nuclear Information System (INIS)

    Merat, S.

    2008-01-01

    Expanding wireless communication network reception inside reactor buildings (RB) and service wings (SW) has always been a technical challenge for operations service team. This is driven by the volume of metal equipment inside the Reactor Buildings (RB) that blocks and somehow shields the signal throughout the link. In this study, to improve wireless reception inside the Reactor Building (RB), an experimental model using indoor localization mesh based on IEEE 802.15 is developed to implement a wireless sensor network. This experimental model estimates the distance between different nodes by measuring the RSSI (Received Signal Strength Indicator). Then by using triangulation and RSSI measurement, the validity of the estimation techniques is verified to simulate the physical environmental obstacles, which block the signal transmission. (author)

  16. Reactor building indoor wireless network channel quality estimation using RSSI measurement of wireless sensor network

    Energy Technology Data Exchange (ETDEWEB)

    Merat, S. [Wardrop Engineering Inc., Toronto, Ontario (Canada)

    2008-07-01

    Expanding wireless communication network reception inside reactor buildings (RB) and service wings (SW) has always been a technical challenge for operations service team. This is driven by the volume of metal equipment inside the Reactor Buildings (RB) that blocks and somehow shields the signal throughout the link. In this study, to improve wireless reception inside the Reactor Building (RB), an experimental model using indoor localization mesh based on IEEE 802.15 is developed to implement a wireless sensor network. This experimental model estimates the distance between different nodes by measuring the RSSI (Received Signal Strength Indicator). Then by using triangulation and RSSI measurement, the validity of the estimation techniques is verified to simulate the physical environmental obstacles, which block the signal transmission. (author)

  17. pO2 measurements in arteriolar networks.

    Science.gov (United States)

    Torres Filho, I P; Kerger, H; Intaglietta, M

    1996-03-01

    Previous studies from our laboratory have shown that the average arteriolar pO2 in the hamster skinfold preparation is lower than arterial systemic pO2. In the present work we tested the hypothesis that there is a longitudinal gradient of pO2 along precapillary vessels. Experiments were performed in Syrian golden hamsters bearing a dorsal skin chamber. The oxygen-dependent quenching of phosphorescence of palladium-porphyrin complexes was used to measure intravascular pO2 in the microcirculation. Arterioles were classified in four orders according to their position in the network, first-order vessels being the entrance points. Simultaneous determinations of diameter (D), red blood cell velocity, and systemic blood gases were also made. There was a significant fall of pO2 between vessels of different orders. First-order arterioles (mean D = 64 microns) had pO2 of 51.8 +/- 9.8 mm Hg (mean +/- SD) which was equivalent to approximately equal to 73% of the arterial systemic pO2. Within the arteriolar network, further decreases of intravascular pO2 were measured, leading to a pO2 of 34.0 +/- 7.9 mm Hg in terminal arterioles (mean D = 7.7 microns). In some vessels pO2 was measured in different positions of the same arteriole. The average longitudinal arteriolar oxygen saturation gradient was 3.4 +/- 0.4 delta %/mm (range 0.8-7.2). A significant and positive correlation was found between pO2 and microhemodynamic parameters when arterioles were grouped according to their order. This relation was not significant for venules which showed a mean pO2 of 30.8 +/- 10.8 mm Hg. Tissue pO2 averaged 24.6 +/- 5.8 mm Hg. We conclude that: (1) There is an oxygen loss in arterial vessels larger than 100 micrograms in diameter, (2) arteriolar pO2 in this preparation depends on the position of the vessel within the network, (3) a substantial portion of oxygen delivery to the hamster skin is provided by the arteriolar network, and (4) only a small pO2 gradient exists between terminal

  18. Defining social inclusion of people with intellectual and developmental disabilities: an ecological model of social networks and community participation.

    Science.gov (United States)

    Simplican, Stacy Clifford; Leader, Geraldine; Kosciulek, John; Leahy, Michael

    2015-03-01

    Social inclusion is an important goal for people with intellectual and developmental disabilities, families, service providers, and policymakers; however, the concept of social inclusion remains unclear, largely due to multiple and conflicting definitions in research and policy. We define social inclusion as the interaction between two major life domains: interpersonal relationships and community participation. We then propose an ecological model of social inclusion that includes individual, interpersonal, organizational, community, and socio-political factors. We identify four areas of research that our ecological model of social inclusion can move forward: (1) organizational implementation of social inclusion; (2) social inclusion of people with intellectual and developmental disabilities living with their families, (3) social inclusion of people along a broader spectrum of disability, and (4) the potential role of self-advocacy organizations in promoting social inclusion. Copyright © 2014. Published by Elsevier Ltd.

  19. Inferring a Drive-Response Network from Time Series of Topological Measures in Complex Networks with Transfer Entropy

    Directory of Open Access Journals (Sweden)

    Xinbo Ai

    2014-11-01

    Full Text Available Topological measures are crucial to describe, classify and understand complex networks. Lots of measures are proposed to characterize specific features of specific networks, but the relationships among these measures remain unclear. Taking into account that pulling networks from different domains together for statistical analysis might provide incorrect conclusions, we conduct our investigation with data observed from the same network in the form of simultaneously measured time series. We synthesize a transfer entropy-based framework to quantify the relationships among topological measures, and then to provide a holistic scenario of these measures by inferring a drive-response network. Techniques from Symbolic Transfer Entropy, Effective Transfer Entropy, and Partial Transfer Entropy are synthesized to deal with challenges such as time series being non-stationary, finite sample effects and indirect effects. We resort to kernel density estimation to assess significance of the results based on surrogate data. The framework is applied to study 20 measures across 2779 records in the Technology Exchange Network, and the results are consistent with some existing knowledge. With the drive-response network, we evaluate the influence of each measure by calculating its strength, and cluster them into three classes, i.e., driving measures, responding measures and standalone measures, according to the network communities.

  20. Love as a subjective corrlate of interpersonal relationships: attempts of defining of the concepts and methods of measurment

    Directory of Open Access Journals (Sweden)

    O. P. Zolotnyik

    2015-04-01

    Full Text Available This article is devoted to overview the scientific study of the phenomenon of love. Attempts of scientific knowledge presented by developed by sociologists and psychologists love theories, which defined, classified and measure this phenomenon. The paper proposed to review the most popular theory of love studying: the triangular theory of love for Robert J. Sternberg, classification styles love for John Alan Lee and transformational concept of A.Giddens. The importance of studying this subject is explained by the subjective definition by respondents of the role of love as correlates of interpersonal relationships. Love is considered as a factor that acts as a marriage motive and components, which ensures its durability. The complexity of the scientific understanding of love is the absence of clear empirical referents for fixation. The examined theory reaffirms their scientific hypotheses through the use of specific methods of measurement. It is offered for review: Scale of love and sympathy by Z.Rubin, Love Attitude Scale by Hendrick C. and Hendrick S. and scale of romantic relationships by Munro­Adams. These methodologies are widely used in modern scientific research, been undergo with modifications and adaptation depending on the cultural characteristics of the respondents. The phenomenon of love needs more scientific study with the aim of further categorization, require range of techniques selection and should be included  as a component in the sociological survey of interpersonal relationships.

  1. Optimal and secure measurement protocols for quantum sensor networks

    Science.gov (United States)

    Eldredge, Zachary; Foss-Feig, Michael; Gross, Jonathan A.; Rolston, S. L.; Gorshkov, Alexey V.

    2018-04-01

    Studies of quantum metrology have shown that the use of many-body entangled states can lead to an enhancement in sensitivity when compared with unentangled states. In this paper, we quantify the metrological advantage of entanglement in a setting where the measured quantity is a linear function of parameters individually coupled to each qubit. We first generalize the Heisenberg limit to the measurement of nonlocal observables in a quantum network, deriving a bound based on the multiparameter quantum Fisher information. We then propose measurement protocols that can make use of Greenberger-Horne-Zeilinger (GHZ) states or spin-squeezed states and show that in the case of GHZ states the protocol is optimal, i.e., it saturates our bound. We also identify nanoscale magnetic resonance imaging as a promising setting for this technology.

  2. Laser tracker error determination using a network measurement

    International Nuclear Information System (INIS)

    Hughes, Ben; Forbes, Alistair; Lewis, Andrew; Sun, Wenjuan; Veal, Dan; Nasr, Karim

    2011-01-01

    We report on a fast, easily implemented method to determine all the geometrical alignment errors of a laser tracker, to high precision. The technique requires no specialist equipment and can be performed in less than an hour. The technique is based on the determination of parameters of a geometric model of the laser tracker, using measurements of a set of fixed target locations, from multiple locations of the tracker. After fitting of the model parameters to the observed data, the model can be used to perform error correction of the raw laser tracker data or to derive correction parameters in the format of the tracker manufacturer's internal error map. In addition to determination of the model parameters, the method also determines the uncertainties and correlations associated with the parameters. We have tested the technique on a commercial laser tracker in the following way. We disabled the tracker's internal error compensation, and used a five-position, fifteen-target network to estimate all the geometric errors of the instrument. Using the error map generated from this network test, the tracker was able to pass a full performance validation test, conducted according to a recognized specification standard (ASME B89.4.19-2006). We conclude that the error correction determined from the network test is as effective as the manufacturer's own error correction methodologies

  3. Automated Measurement and Signaling Systems for the Transactional Network

    Energy Technology Data Exchange (ETDEWEB)

    Piette, Mary Ann; Brown, Richard; Price, Phillip; Page, Janie; Granderson, Jessica; Riess, David; Czarnecki, Stephen; Ghatikar, Girish; Lanzisera, Steven

    2013-12-31

    The Transactional Network Project is a multi-lab activity funded by the US Department of Energy?s Building Technologies Office. The project team included staff from Lawrence Berkeley National Laboratory, Pacific Northwest National Laboratory and Oak Ridge National Laboratory. The team designed, prototyped and tested a transactional network (TN) platform to support energy, operational and financial transactions between any networked entities (equipment, organizations, buildings, grid, etc.). PNNL was responsible for the development of the TN platform, with agents for this platform developed by each of the three labs. LBNL contributed applications to measure the whole-building electric load response to various changes in building operations, particularly energy efficiency improvements and demand response events. We also provide a demand response signaling agent and an agent for cost savings analysis. LBNL and PNNL demonstrated actual transactions between packaged rooftop units and the electric grid using the platform and selected agents. This document describes the agents and applications developed by the LBNL team, and associated tests of the applications.

  4. Hierarchical anatomical brain networks for MCI prediction: revisiting volumetric measures.

    Directory of Open Access Journals (Sweden)

    Luping Zhou

    Full Text Available Owning to its clinical accessibility, T1-weighted MRI (Magnetic Resonance Imaging has been extensively studied in the past decades for prediction of Alzheimer's disease (AD and mild cognitive impairment (MCI. The volumes of gray matter (GM, white matter (WM and cerebrospinal fluid (CSF are the most commonly used measurements, resulting in many successful applications. It has been widely observed that disease-induced structural changes may not occur at isolated spots, but in several inter-related regions. Therefore, for better characterization of brain pathology, we propose in this paper a means to extract inter-regional correlation based features from local volumetric measurements. Specifically, our approach involves constructing an anatomical brain network for each subject, with each node representing a Region of Interest (ROI and each edge representing Pearson correlation of tissue volumetric measurements between ROI pairs. As second order volumetric measurements, network features are more descriptive but also more sensitive to noise. To overcome this limitation, a hierarchy of ROIs is used to suppress noise at different scales. Pairwise interactions are considered not only for ROIs with the same scale in the same layer of the hierarchy, but also for ROIs across different scales in different layers. To address the high dimensionality problem resulting from the large number of network features, a supervised dimensionality reduction method is further employed to embed a selected subset of features into a low dimensional feature space, while at the same time preserving discriminative information. We demonstrate with experimental results the efficacy of this embedding strategy in comparison with some other commonly used approaches. In addition, although the proposed method can be easily generalized to incorporate other metrics of regional similarities, the benefits of using Pearson correlation in our application are reinforced by the experimental

  5. Augmented Lagrange Programming Neural Network for Localization Using Time-Difference-of-Arrival Measurements.

    Science.gov (United States)

    Han, Zifa; Leung, Chi Sing; So, Hing Cheung; Constantinides, Anthony George

    2017-08-15

    A commonly used measurement model for locating a mobile source is time-difference-of-arrival (TDOA). As each TDOA measurement defines a hyperbola, it is not straightforward to compute the mobile source position due to the nonlinear relationship in the measurements. This brief exploits the Lagrange programming neural network (LPNN), which provides a general framework to solve nonlinear constrained optimization problems, for the TDOA-based localization. The local stability of the proposed LPNN solution is also analyzed. Simulation results are included to evaluate the localization accuracy of the LPNN scheme by comparing with the state-of-the-art methods and the optimality benchmark of Cramér-Rao lower bound.

  6. Resting-state test-retest reliability of a priori defined canonical networks over different preprocessing steps

    NARCIS (Netherlands)

    Varikuti, D.P.; Hoffstaedter, F.; Genon, S.; Schwender, H.; Reid, A.T.; Eickhoff, S.B.

    2017-01-01

    Resting-state functional connectivity analysis has become a widely used method for the investigation of human brain connectivity and pathology. The measurement of neuronal activity by functional MRI, however, is impeded by various nuisance signals that reduce the stability of functional

  7. Calibration-measurement unit for the automation of vector network analyzer measurements

    Directory of Open Access Journals (Sweden)

    I. Rolfes

    2008-05-01

    Full Text Available With the availability of multi-port vector network analyzers, the need for automated, calibrated measurement facilities increases. In this contribution, a calibration-measurement unit is presented which realizes a repeatable automated calibration of the measurement setup as well as a user-friendly measurement of the device under test (DUT. In difference to commercially available calibration units, which are connected to the ports of the vector network analyzer preceding a measurement and which are then removed so that the DUT can be connected, the presented calibration-measurement unit is permanently connected to the ports of the VNA for the calibration as well as for the measurement of the DUT. This helps to simplify the calibrated measurement of complex scattering parameters. Moreover, a full integration of the calibration unit into the analyzer setup becomes possible. The calibration-measurement unit is based on a multiport switch setup of e.g. electromechanical relays. Under the assumption of symmetry of a switch, on the one hand the unit realizes the connection of calibration standards like one-port reflection standards and two-port through connections between different ports and on the other hand it enables the connection of the DUT. The calibration-measurement unit is applicable for two-port VNAs as well as for multiport VNAs. For the calibration of the unit, methods with completely known calibration standards like SOLT (short, open, load, through as well as self-calibration procedures like TMR or TLR can be applied.

  8. Measuring social networks in British primary schools through scientific engagement

    Science.gov (United States)

    Conlan, A. J. K.; Eames, K. T. D.; Gage, J. A.; von Kirchbach, J. C.; Ross, J. V.; Saenz, R. A.; Gog, J. R.

    2011-01-01

    Primary schools constitute a key risk group for the transmission of infectious diseases, concentrating great numbers of immunologically naive individuals at high densities. Despite this, very little is known about the social patterns of mixing within a school, which are likely to contribute to disease transmission. In this study, we present a novel approach where scientific engagement was used as a tool to access school populations and measure social networks between young (4–11 years) children. By embedding our research project within enrichment activities to older secondary school (13–15) children, we could exploit the existing links between schools to achieve a high response rate for our study population (around 90% in most schools). Social contacts of primary school children were measured through self-reporting based on a questionnaire design, and analysed using the techniques of social network analysis. We find evidence of marked social structure and gender assortativity within and between classrooms in the same school. These patterns have been previously reported in smaller studies, but to our knowledge no study has attempted to exhaustively sample entire school populations. Our innovative approach facilitates access to a vitally important (but difficult to sample) epidemiological sub-group. It provides a model whereby scientific communication can be used to enhance, rather than merely complement, the outcomes of research. PMID:21047859

  9. Single-cell quantitative HER2 measurement identifies heterogeneity and distinct subgroups within traditionally defined HER2-positive patients.

    Science.gov (United States)

    Onsum, Matthew D; Geretti, Elena; Paragas, Violette; Kudla, Arthur J; Moulis, Sharon P; Luus, Lia; Wickham, Thomas J; McDonagh, Charlotte F; MacBeath, Gavin; Hendriks, Bart S

    2013-11-01

    Human epidermal growth factor receptor 2 (HER2) is an important biomarker for breast and gastric cancer prognosis and patient treatment decisions. HER2 positivity, as defined by IHC or fluorescent in situ hybridization testing, remains an imprecise predictor of patient response to HER2-targeted therapies. Challenges to correct HER2 assessment and patient stratification include intratumoral heterogeneity, lack of quantitative and/or objective assays, and differences between measuring HER2 amplification at the protein versus gene level. We developed a novel immunofluorescence method for quantitation of HER2 protein expression at the single-cell level on FFPE patient samples. Our assay uses automated image analysis to identify and classify tumor versus non-tumor cells, as well as quantitate the HER2 staining for each tumor cell. The HER2 staining level is converted to HER2 protein expression using a standard cell pellet array stained in parallel with the tissue sample. This approach allows assessment of HER2 expression and heterogeneity within a tissue section at the single-cell level. By using this assay, we identified distinct subgroups of HER2 heterogeneity within traditional definitions of HER2 positivity in both breast and gastric cancers. Quantitative assessment of intratumoral HER2 heterogeneity may offer an opportunity to improve the identification of patients likely to respond to HER2-targeted therapies. The broad applicability of the assay was demonstrated by measuring HER2 expression profiles on multiple tumor types, and on normal and diseased heart tissues. Copyright © 2013 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

  10. Ekofisk chalk: core measurements, stochastic reconstruction, network modeling and simulation

    Energy Technology Data Exchange (ETDEWEB)

    Talukdar, Saifullah

    2002-07-01

    This dissertation deals with (1) experimental measurements on petrophysical, reservoir engineering and morphological properties of Ekofisk chalk, (2) numerical simulation of core flood experiments to analyze and improve relative permeability data, (3) stochastic reconstruction of chalk samples from limited morphological information, (4) extraction of pore space parameters from the reconstructed samples, development of network model using pore space information, and computation of petrophysical and reservoir engineering properties from network model, and (5) development of 2D and 3D idealized fractured reservoir models and verification of the applicability of several widely used conventional up scaling techniques in fractured reservoir simulation. Experiments have been conducted on eight Ekofisk chalk samples and porosity, absolute permeability, formation factor, and oil-water relative permeability, capillary pressure and resistivity index are measured at laboratory conditions. Mercury porosimetry data and backscatter scanning electron microscope images have also been acquired for the samples. A numerical simulation technique involving history matching of the production profiles is employed to improve the relative permeability curves and to analyze hysteresis of the Ekofisk chalk samples. The technique was found to be a powerful tool to supplement the uncertainties in experimental measurements. Porosity and correlation statistics obtained from backscatter scanning electron microscope images are used to reconstruct microstructures of chalk and particulate media. The reconstruction technique involves a simulated annealing algorithm, which can be constrained by an arbitrary number of morphological parameters. This flexibility of the algorithm is exploited to successfully reconstruct particulate media and chalk samples using more than one correlation functions. A technique based on conditional simulated annealing has been introduced for exact reproduction of vuggy

  11. Preferential Attachment in Online Networks: Measurement and Explanations

    NARCIS (Netherlands)

    Kunegis, J; Blattner, M; Moser, C.

    2013-01-01

    We perform an empirical study of the preferential attachment phenomenon in temporal networks and show that on the Web, networks follow a nonlinear preferential attachment model in which the exponent depends on the type of network considered. The classical preferential attachment model for networks

  12. Energy Consumption Model and Measurement Results for Network Coding-enabled IEEE 802.11 Meshed Wireless Networks

    DEFF Research Database (Denmark)

    Paramanathan, Achuthan; Rasmussen, Ulrik Wilken; Hundebøll, Martin

    2012-01-01

    This paper presents an energy model and energy measurements for network coding enabled wireless meshed networks based on IEEE 802.11 technology. The energy model and the energy measurement testbed is limited to a simple Alice and Bob scenario. For this toy scenario we compare the energy usages...... for a system with and without network coding support. While network coding reduces the number of radio transmissions, the operational activity on the devices due to coding will be increased. We derive an analytical model for the energy consumption and compare it to real measurements for which we build...... a flexible, low cost tool to be able to measure at any given node in a meshed network. We verify the precision of our tool by comparing it to a sophisticated device. Our main results in this paper are the derivation of an analytical energy model, the implementation of a distributed energy measurement testbed...

  13. Quantifying the value of redundant measurements at GCOS Reference Upper-Air Network sites

    Directory of Open Access Journals (Sweden)

    F. Madonna

    2014-11-01

    Full Text Available The potential for measurement redundancy to reduce uncertainty in atmospheric variables has not been investigated comprehensively for climate observations. We evaluated the usefulness of entropy and mutual correlation concepts, as defined in information theory, for quantifying random uncertainty and redundancy in time series of the integrated water vapour (IWV and water vapour mixing ratio profiles provided by five highly instrumented GRUAN (GCOS, Global Climate Observing System, Reference Upper-Air Network stations in 2010–2012. Results show that the random uncertainties on the IWV measured with radiosondes, global positioning system, microwave and infrared radiometers, and Raman lidar measurements differed by less than 8%. Comparisons of time series of IWV content from ground-based remote sensing instruments with in situ soundings showed that microwave radiometers have the highest redundancy with the IWV time series measured by radiosondes and therefore the highest potential to reduce the random uncertainty of the radiosondes time series. Moreover, the random uncertainty of a time series from one instrument can be reduced by ~ 60% by constraining the measurements with those from another instrument. The best reduction of random uncertainty is achieved by conditioning Raman lidar measurements with microwave radiometer measurements. Specific instruments are recommended for atmospheric water vapour measurements at GRUAN sites. This approach can be applied to the study of redundant measurements for other climate variables.

  14. SKYMONITOR: A Global Network for Sky Brightness Measurements

    Science.gov (United States)

    Davis, Donald R.; Mckenna, D.; Pulvermacher, R.; Everett, M.

    2010-01-01

    We are implementing a global network to measure sky brightness at dark-sky critical sites with the goal of creating a multi-decade database. The heart of this project is the Night Sky Brightness Monitor (NSBM), an autonomous 2 channel photometer which measures night sky brightness in the visual wavelengths (Mckenna et al, AAS 2009). Sky brightness is measured every minute at two elevation angles typically zenith and 20 degrees to monitor brightness and transparency. The NSBM consists of two parts, a remote unit and a base station with an internet connection. Currently these devices use 2.4 Ghz transceivers with a range of 100 meters. The remote unit is battery powered with daytime recharging using a solar panel. Data received by the base unit is transmitted via email protocol to IDA offices in Tucson where it will be collected, archived and made available to the user community via a web interface. Two other versions of the NSBM are under development: one for radio sensitive areas using an optical fiber link and the second that reads data directly to a laptop for sites without internet access. NSBM units are currently undergoing field testing at two observatories. With support from the National Science Foundation, we will construct and install a total of 10 units at astronomical observatories. With additional funding, we will locate additional units at other sites such as National Parks, dark-sky preserves and other sites where dark sky preservation is crucial. We will present the current comparison with the National Park Service sky monitoring camera. We anticipate that the SKYMONITOR network will be functioning by the end of 2010.

  15. Node-based measures of connectivity in genetic networks.

    Science.gov (United States)

    Koen, Erin L; Bowman, Jeff; Wilson, Paul J

    2016-01-01

    At-site environmental conditions can have strong influences on genetic connectivity, and in particular on the immigration and settlement phases of dispersal. However, at-site processes are rarely explored in landscape genetic analyses. Networks can facilitate the study of at-site processes, where network nodes are used to model site-level effects. We used simulated genetic networks to compare and contrast the performance of 7 node-based (as opposed to edge-based) genetic connectivity metrics. We simulated increasing node connectivity by varying migration in two ways: we increased the number of migrants moving between a focal node and a set number of recipient nodes, and we increased the number of recipient nodes receiving a set number of migrants. We found that two metrics in particular, the average edge weight and the average inverse edge weight, varied linearly with simulated connectivity. Conversely, node degree was not a good measure of connectivity. We demonstrated the use of average inverse edge weight to describe the influence of at-site habitat characteristics on genetic connectivity of 653 American martens (Martes americana) in Ontario, Canada. We found that highly connected nodes had high habitat quality for marten (deep snow and high proportions of coniferous and mature forest) and were farther from the range edge. We recommend the use of node-based genetic connectivity metrics, in particular, average edge weight or average inverse edge weight, to model the influences of at-site habitat conditions on the immigration and settlement phases of dispersal. © 2015 John Wiley & Sons Ltd.

  16. Development of Light Powered Sensor Networks for Thermal Comfort Measurement

    Directory of Open Access Journals (Sweden)

    Dasheng Lee

    2008-10-01

    Full Text Available Recent technological advances in wireless communications have enabled easy installation of sensor networks with air conditioning equipment control applications. However, the sensor node power supply, through either power lines or battery power, still presents obstacles to the distribution of the sensing systems. In this study, a novel sensor network, powered by the artificial light, was constructed to achieve wireless power transfer and wireless data communications for thermal comfort measurements. The sensing node integrates an IC-based temperature sensor, a radiation thermometer, a relative humidity sensor, a micro machined flow sensor and a microprocessor for predicting mean vote (PMV calculation. The 935 MHz band RF module was employed for the wireless data communication with a specific protocol based on a special energy beacon enabled mode capable of achieving zero power consumption during the inactive periods of the nodes. A 5W spotlight, with a dual axis tilt platform, can power the distributed nodes over a distance of up to 5 meters. A special algorithm, the maximum entropy method, was developed to estimate the sensing quantity of climate parameters if the communication module did not receive any response from the distributed nodes within a certain time limit. The light-powered sensor networks were able to gather indoor comfort-sensing index levels in good agreement with the comfort-sensing vote (CSV preferred by a human being and the experimental results within the environment suggested that the sensing system could be used in air conditioning systems to implement a comfort-optimal control strategy.

  17. Black Carbon Measurements From Ireland's Transboundary Network (TXB)

    Science.gov (United States)

    Spohn, T. K.; Martin, D.; O'Dowd, C. D. D.

    2017-12-01

    Black Carbon (BC) is carbonaceous aerosol formed by incomplete fossil fuel combustion. Named for its light absorbing properties, it acts to trap heat in the atmosphere, thus behaving like a greenhouse gas, and is considered a strong, short-lived climate forcer by the International Panel on Climate Change (IPCC). Carbonaceous aerosols from biomass burning (BB) such as forest fires and residential wood burning, also known as brown carbon, affect the ultra violet (UV) light absorption in the atmosphere as well. In 2016 a three node black carbon monitoring network was established in Ireland as part of a Transboundary Monitoring Network (TXB). The three sites (Mace Head, Malin Head, and Carnsore Point) are coastal locations on opposing sides of the country, and offer the opportunity to assess typical northern hemispheric background concentrations as well national and European pollution events. The instruments deployed in this network (Magee Scientific AE33) facilitate elimination of the changes in response due to `aerosol loading' effects; and a real-time calculation of the `loading compensation' parameter which offers insights into aerosol optical properties. Additionally, these instruments have an inbuilt algorithm, which estimates the difference in absorption in the ultraviolet wavelengths (mostly by brown carbon) and the near infrared wavelengths (only by black carbon).Presented here are the first results of the BC measurements from the three Irish stations, including instrument validation, seasonal variation as well as local, regional, and transboundary influences based on air mass trajectories as well as concurrent in-situ observations (meteorological parameters, particle number, and aerosol composition). A comparison of the instrumental algorithm to off-line sensitivity calculations will also be made to assess the contribution of biomass burning to BC pollution events.

  18. Continuous measurements of methane from a tower network over Siberia

    International Nuclear Information System (INIS)

    Sasakawa, M.; Machida, T.; Saeki, T.; Koyama, Y.; Maksyutov, S.; Shimoyama, K.; Tsuda, N.; Suto, H.; Arshinov, M.; Davydov, D.; Fofonov, A.; Krasnov, O.

    2010-01-01

    We have been conducting continuous measurements of Methane (CH 4 ) concentration from an expanding network of towers (JR-STATION: Japan-Russia Siberian Tall Tower Inland Observation Network) located in taiga, steppe and wetland biomes of Siberia since 2004. High daytime means (>2000 ppb) observed simultaneously at several towers during winter, together with in situ weather data and NCEP/NCAR reanalysis data, indicate that high pressure systems caused CH 4 accumulation at subcontinental scale due to the widespread formation of an inversion layer. Daytime means sometimes exceeded 2000 ppb, particularly in the summer of 2007 when temperature and precipitation rates were anomalously high over West Siberia, which implies that CH 4 emission from wetlands were exceptionally high in 2007. Many hot spots detected by MODIS in the summer of 2007 illustrate that the contribution of biomass burning also cannot be neglected. Daytime mean CH 4 concentrations from the Siberian tower sites were generally higher than CH 4 values reported at NOAA coastal sites in the same latitudinal zone, and the difference in concentrations between two sets of sites was reproduced with a coupled Eulerian-Lagrangian transport model. Simulations of emissions from different CH 4 sources suggested that the major contributor to variation switched from wetlands during summer to fossil fuel during winter.

  19. Continuous measurements of methane from a tower network over Siberia

    Energy Technology Data Exchange (ETDEWEB)

    Sasakawa, M.; Machida, T.; Saeki, T.; Koyama, Y.; Maksyutov, S. (Center for Global Environmental Research, National Inst. for Environmental Studies, Tsukuba, Ibaraki (Japan)); Shimoyama, K. (Inst. of Low Temperature Science, Hokkaido Univ., Hokkaido (Japan)); Tsuda, N. (Global Environmental Forum, Tokyo (Japan)); Suto, H. (Japan Aerospace Exploration Agency (Japan)); Arshinov, M.; Davydov, D.; Fofonov, A.; Krasnov, O. (Inst. of Atmospheric Optics, Russian Academy of Sciences, Siberian Branch (Russian Federation))

    2010-11-15

    We have been conducting continuous measurements of Methane (CH{sub 4}) concentration from an expanding network of towers (JR-STATION: Japan-Russia Siberian Tall Tower Inland Observation Network) located in taiga, steppe and wetland biomes of Siberia since 2004. High daytime means (>2000 ppb) observed simultaneously at several towers during winter, together with in situ weather data and NCEP/NCAR reanalysis data, indicate that high pressure systems caused CH{sub 4} accumulation at subcontinental scale due to the widespread formation of an inversion layer. Daytime means sometimes exceeded 2000 ppb, particularly in the summer of 2007 when temperature and precipitation rates were anomalously high over West Siberia, which implies that CH{sub 4} emission from wetlands were exceptionally high in 2007. Many hot spots detected by MODIS in the summer of 2007 illustrate that the contribution of biomass burning also cannot be neglected. Daytime mean CH{sub 4} concentrations from the Siberian tower sites were generally higher than CH{sub 4} values reported at NOAA coastal sites in the same latitudinal zone, and the difference in concentrations between two sets of sites was reproduced with a coupled Eulerian-Lagrangian transport model. Simulations of emissions from different CH{sub 4} sources suggested that the major contributor to variation switched from wetlands during summer to fossil fuel during winter.

  20. Grain bulk density measurement based on wireless network

    Directory of Open Access Journals (Sweden)

    Wu Fangming

    2017-01-01

    Full Text Available To know the accurate quantity of stored grain, grain density sensors must be used to measure the grain’s bulk density. However, multi-sensors should be inserted into the storage facility, to quickly collect data during the inventory checking of stored grain. In this study, the ZigBee and Wi-Fi coexistence network’s ability to transmit data collected by density sensors was investigated. A system consisting of six sensor nodes, six router nodes, one gateway and one Android Pad was assembled to measure the grain’s bulk density and calculate its quantity. The CC2530 chip with ZigBee technology was considered as the core of the information processing, and wireless nodes detection in sensor, and router nodes. ZigBee worked in difference signal channel with Wi-Fi to avoid interferences and connected with Wi-Fi module by UART serial communications interfaces in gateway. The Android Pad received the measured data through the gateway and processed this data to calculate quantity. The system enabled multi-point and real-time parameter detection inside the grain storage. Results show that the system has characteristics of good expansibility, networking flexibility and convenience.

  1. Multi-attribute integrated measurement of node importance in complex networks.

    Science.gov (United States)

    Wang, Shibo; Zhao, Jinlou

    2015-11-01

    The measure of node importance in complex networks is very important to the research of networks stability and robustness; it also can ensure the security of the whole network. Most researchers have used a single indicator to measure the networks node importance, so that the obtained measurement results only reflect certain aspects of the networks with a loss of information. Meanwhile, because of the difference of networks topology, the nodes' importance should be described by combining the character of the networks topology. Most of the existing evaluation algorithms cannot completely reflect the circumstances of complex networks, so this paper takes into account the degree of centrality, the relative closeness centrality, clustering coefficient, and topology potential and raises an integrated measuring method to measure the nodes' importance. This method can reflect nodes' internal and outside attributes and eliminate the influence of network structure on the node importance. The experiments of karate network and dolphin network show that networks topology structure integrated measure has smaller range of metrical result than a single indicator and more universal. Experiments show that attacking the North American power grid and the Internet network with the method has a faster convergence speed than other methods.

  2. Research on the method of measuring space information network capacity in communication service

    Directory of Open Access Journals (Sweden)

    Zhu Shichao

    2017-02-01

    Full Text Available Because of the large scale characteristic of space information network in terms of space and time and the increasing of its complexity,existing measuring methods of information transmission capacity have been unable to measure the existing and future space information networkeffectively.In this study,we firstly established a complex model of space information network,and measured the whole space information network capacity by means of analyzing data access capability to the network and data transmission capability within the network.At last,we verified the rationality of the proposed measuring method by using STK and Matlab simulation software for collaborative simulation.

  3. Flow-based vulnerability measures for network component importance: Experimentation with preparedness planning

    International Nuclear Information System (INIS)

    Nicholson, Charles D.; Barker, Kash; Ramirez-Marquez, Jose E.

    2016-01-01

    This work develops and compares several flow-based vulnerability measures to prioritize important network edges for the implementation of preparedness options. These network vulnerability measures quantify different characteristics and perspectives on enabling maximum flow, creating bottlenecks, and partitioning into cutsets, among others. The efficacy of these vulnerability measures to motivate preparedness options against experimental geographically located disruption simulations is measured. Results suggest that a weighted flow capacity rate, which accounts for both (i) the contribution of an edge to maximum network flow and (ii) the extent to which the edge is a bottleneck in the network, shows most promise across four instances of varying network sizes and densities. - Highlights: • We develop new flow-based measures of network vulnerability. • We apply these measures to determine the importance of edges after disruptions. • Networks of varying size and density are explored.

  4. New approach in subjective and objective speech transmission quality measurement in TCP/IP networks

    International Nuclear Information System (INIS)

    Souček, Pavel; Slavata, Oldřich; Holub, Jan

    2015-01-01

    This paper deals with problems of speech transmission quality measurement in modern telecommunication networks. It focuses on problems caused by specific types of distortions and errors caused present in transmissions using TCP/IP networks

  5. Measurement of traffic network vulnerability for Mississippi coastal region : final research report.

    Science.gov (United States)

    2017-08-15

    Natural disasters such as a hurricane can cause great damages to the transportation networks and significantly affect the evacuation trip operations. An accurate understanding and measurement of the network vulnerability can enhance the evacuees p...

  6. A Network-Based Impact Measure for Propagated Losses in a Supply Chain Network Consisting of Resilient Components

    Directory of Open Access Journals (Sweden)

    Jesus Felix Bayta Valenzuela

    2018-01-01

    Full Text Available The topology of a supply chain network affects the impacts of disruptions in it. We formulate a network-based measure of the impact of a disruption loss in a supply chain propagating downstream from an originating node. The measure takes into account the loss profile of the originating node, the structure of the supply network, and the resilience of the network components. We obtain an analytical expression for the impact measure under a beta-distributed initial loss (generalizable to any continuous distribution supported on the interval 0,1, under a breakthrough scenario (in which a fraction of the initial production loss reaches a focal company downstream as opposed to containment upstream or at the originating point. Furthermore, we obtain a closed-form solution for a supply chain network with a k-ary tree topology; a numerical study is performed for a scale-free network and a random network. Our proposed approach enables the evaluation of potential losses for a focal company considering its supply chain network structure, which may help the company to plan or redesign a robust and resilient network in response to different types of disruptions.

  7. Stream network responses to evapotranspiration in mountain systems: evidence from spatially-distributed network mapping and sapflow measurements

    Science.gov (United States)

    Godsey, S.; Whiting, J. A.; Reinhardt, K.

    2015-12-01

    Stream networks respond to decreased inputs by shrinking from their headwaters and disconnecting along their length. Both the relative stability of the stream network and the degree of disconnection along the network length can strongly affect stream ecology, including fish migration and nutrient spiraling. Previous data suggests that stream network lengths decrease measurably as discharge decreases, and that evapotranspiration may be an important control on stream network persistence. We hypothesized that changes in sapflow timing and magnitude across a gradient from rain-dominated to snow-dominated elevations would be reflected in the stability of the stream network in a steep watershed draining to the Middle Fork Salmon in central Idaho. We expected that the relative timing of water availability across the gradient would drive differences in water delivery to both trees and the stream network. Here we present results that highlight the stability of sapflow timing across the gradient and persistence of the stream network at this site. We discuss geologic controls on network stability and present a conceptual framework identifying characteristics of stable flowheads. We test this framework at four sites in central Idaho with mapped stream networks. We also discuss late summer sapflow patterns across the elevation gradient and their linkages to soil and atmospheric characteristics. Finally, we compare these patterns to those observed at other sites and discuss the role of vegetation in controlling spatiotemporal patterns across the stream network.

  8. Procedure to measure real time latency using software defined radio in a W-band fiber-wireless link

    DEFF Research Database (Denmark)

    Rico-Martínez, Mónica; Morales, Alvaro; Mehmeri, Victor

    2017-01-01

    Reducing latency is a major challenge for current telecommunications systems. 5G networks are envisioned to achieve end-to-end latencies below 1 ms, thus enabling the Internet of Things (IoT) evolution and new applications such as Tactile Internet. In this article, we present a new procedure...

  9. Measurement of circulating transcripts and gene cluster analysis predicts and defines therapeutic efficacy of peptide receptor radionuclide therapy (PRRT) in neuroendocrine tumors

    International Nuclear Information System (INIS)

    Bodei, L.; Kidd, M.; Modlin, I.M.; Severi, S.; Nicolini, S.; Paganelli, G.; Drozdov, I.; Kwekkeboom, D.J.; Krenning, E.P.; Baum, R.P.

    2016-01-01

    Peptide receptor radionuclide therapy (PRRT) is an effective method for treating neuroendocrine tumors (NETs). It is limited, however, in the prediction of individual tumor response and the precise and early identification of changes in tumor size. Currently, response prediction is based on somatostatin receptor expression and efficacy by morphological imaging and/or chromogranin A (CgA) measurement. The aim of this study was to assess the accuracy of circulating NET transcripts as a measure of PRRT efficacy, and moreover to identify prognostic gene clusters in pretreatment blood that could be interpolated with relevant clinical features in order to define a biological index for the tumor and a predictive quotient for PRRT efficacy. NET patients (n = 54), M: F 37:17, median age 66, bronchial: n = 13, GEP-NET: n = 35, CUP: n = 6 were treated with 177 Lu-based-PRRT (cumulative activity: 6.5-27.8 GBq, median 18.5). At baseline: 47/54 low-grade (G1/G2; bronchial typical/atypical), 31/49 18 FDG positive and 39/54 progressive. Disease status was assessed by RECIST1.1. Transcripts were measured by real-time quantitative reverse transcription PCR (qRT-PCR) and multianalyte algorithmic analysis (NETest); CgA by enzyme-linked immunosorbent assay (ELISA). Gene cluster (GC) derivations: regulatory network, protein:protein interactome analyses. Statistical analyses: chi-square, non-parametric measurements, multiple regression, receiver operating characteristic and Kaplan-Meier survival. The disease control rate was 72 %. Median PFS was not achieved (follow-up: 1-33 months, median: 16). Only grading was associated with response (p < 0.01). At baseline, 94 % of patients were NETest-positive, while CgA was elevated in 59 %. NETest accurately (89 %, χ 2 = 27.4; p = 1.2 x 10 -7 ) correlated with treatment response, while CgA was 24 % accurate. Gene cluster expression (growth-factor signalome and metabolome) had an AUC of 0.74 ± 0.08 (z-statistic = 2.92, p < 0.004) for predicting

  10. Measurement of circulating transcripts and gene cluster analysis predicts and defines therapeutic efficacy of peptide receptor radionuclide therapy (PRRT) in neuroendocrine tumors

    Energy Technology Data Exchange (ETDEWEB)

    Bodei, L. [European Institute of Oncology, Division of Nuclear Medicine, Milan (Italy); LuGenIum Consortium, Milan, Rotterdam, Bad Berka, London, Italy, Netherlands, Germany (Country Unknown); Kidd, M. [Wren Laboratories, Branford, CT (United States); Modlin, I.M. [LuGenIum Consortium, Milan, Rotterdam, Bad Berka, London, Italy, Netherlands, Germany (Country Unknown); Yale School of Medicine, New Haven, CT (United States); Severi, S.; Nicolini, S.; Paganelli, G. [Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, Nuclear Medicine and Radiometabolic Units, Meldola (Italy); Drozdov, I. [Bering Limited, London (United Kingdom); Kwekkeboom, D.J.; Krenning, E.P. [LuGenIum Consortium, Milan, Rotterdam, Bad Berka, London, Italy, Netherlands, Germany (Country Unknown); Erasmus Medical Center, Nuclear Medicine Department, Rotterdam (Netherlands); Baum, R.P. [LuGenIum Consortium, Milan, Rotterdam, Bad Berka, London, Italy, Netherlands, Germany (Country Unknown); Zentralklinik Bad Berka, Theranostics Center for Molecular Radiotherapy and Imaging, Bad Berka (Germany)

    2016-05-15

    Peptide receptor radionuclide therapy (PRRT) is an effective method for treating neuroendocrine tumors (NETs). It is limited, however, in the prediction of individual tumor response and the precise and early identification of changes in tumor size. Currently, response prediction is based on somatostatin receptor expression and efficacy by morphological imaging and/or chromogranin A (CgA) measurement. The aim of this study was to assess the accuracy of circulating NET transcripts as a measure of PRRT efficacy, and moreover to identify prognostic gene clusters in pretreatment blood that could be interpolated with relevant clinical features in order to define a biological index for the tumor and a predictive quotient for PRRT efficacy. NET patients (n = 54), M: F 37:17, median age 66, bronchial: n = 13, GEP-NET: n = 35, CUP: n = 6 were treated with {sup 177}Lu-based-PRRT (cumulative activity: 6.5-27.8 GBq, median 18.5). At baseline: 47/54 low-grade (G1/G2; bronchial typical/atypical), 31/49 {sup 18}FDG positive and 39/54 progressive. Disease status was assessed by RECIST1.1. Transcripts were measured by real-time quantitative reverse transcription PCR (qRT-PCR) and multianalyte algorithmic analysis (NETest); CgA by enzyme-linked immunosorbent assay (ELISA). Gene cluster (GC) derivations: regulatory network, protein:protein interactome analyses. Statistical analyses: chi-square, non-parametric measurements, multiple regression, receiver operating characteristic and Kaplan-Meier survival. The disease control rate was 72 %. Median PFS was not achieved (follow-up: 1-33 months, median: 16). Only grading was associated with response (p < 0.01). At baseline, 94 % of patients were NETest-positive, while CgA was elevated in 59 %. NETest accurately (89 %, χ{sup 2} = 27.4; p = 1.2 x 10{sup -7}) correlated with treatment response, while CgA was 24 % accurate. Gene cluster expression (growth-factor signalome and metabolome) had an AUC of 0.74 ± 0.08 (z-statistic = 2.92, p < 0

  11. Design, Development and Pre-Flight Testing of the Communications, Navigation, and Networking Reconfigurable Testbed (Connect) to Investigate Software Defined Radio Architecture on the International Space Station

    Science.gov (United States)

    Over, Ann P.; Barrett, Michael J.; Reinhart, Richard C.; Free, James M.; Cikanek, Harry A., III

    2011-01-01

    The Communication Navigation and Networking Reconfigurable Testbed (CoNNeCT) is a NASA-sponsored mission, which will investigate the usage of Software Defined Radios (SDRs) as a multi-function communication system for space missions. A softwaredefined radio system is a communication system in which typical components of the system (e.g., modulators) are incorporated into software. The software-defined capability allows flexibility and experimentation in different modulation, coding and other parameters to understand their effects on performance. This flexibility builds inherent redundancy and flexibility into the system for improved operational efficiency, real-time changes to space missions and enhanced reliability/redundancy. The CoNNeCT Project is a collaboration between industrial radio providers and NASA. The industrial radio providers are providing the SDRs and NASA is designing, building and testing the entire flight system. The flight system will be integrated on the Express Logistics Carrier (ELC) on the International Space Station (ISS) after launch on the H-IIB Transfer Vehicle in 2012. This paper provides an overview of the technology research objectives, payload description, design challenges and pre-flight testing results.

  12. On measurement noise in the European TWSTFT network.

    Science.gov (United States)

    Piester, Dirk; Bauch, Andreas; Becker, Jürgen; Staliuniene, Egle; Schlunegger, Christian

    2008-09-01

    Two-way satellite time and frequency transfer (TWSTFT) using geostationary telecommunication satellites is widely used in the timing community today and has also been chosen as the primary means to effect synchronization of elements of the ground segment of the European satellite navigation system Galileo. We investigated the link performance in a multistation network based on operational parameters such as the number of simultaneously transmitting stations, transmit and receive power, and chip rates of the pseudorandom noise modulation of the transmitted signals. Our work revealed that TWSTFT through a "quiet" transponder channel (2 stations transmitting only) leads to a measurement noise, expressed by the 1 pps jitter, reduced by a factor of 1.4 compared with a busy transponder carrying signals of 12 stations. The frequency transfer capability expressed by the Allan deviation is reduced at short averaging times by the same amount. At averaging times of >1 d, no such reduction could be observed, which points to the fact that other noise sources dominate at such averaging times. We also found that higher transmit power increases the carrier-to-noise density ratio at the receive station and thus entails lower jitter but causes interference with other station's signals. In addition, the use of lower chip rates, which could be accommodated by a reduced assigned bandwidth on the satellite transponder, is not recommended. The 1 pps jitter would go up by a factor of 2.5 when going from 2.5 MCh/s to 1 MCh/s. The 2 Galileo precise timing facilities (PTFs) can be included in the currently operated network of 12 stations in Europe and all requirements on the TWSTFT performance can be met, provided that suitable ground equipment will be installed in the Galileo ground segment.

  13. Assessment of Performance Measures for Security of the Maritime Transportation Network, Port Security Metrics : Proposed Measurement of Deterrence Capability

    Science.gov (United States)

    2007-01-03

    This report is the thirs in a series describing the development of performance measures pertaining to the security of the maritime transportation network (port security metrics). THe development of measures to guide improvements in maritime security ...

  14. The Study on the Communication Network of Wide Area Measurement System in Electricity Grid

    Science.gov (United States)

    Xiaorong, Cheng; Ying, Wang; Yangdan, Ni

    Wide area measurement system(WAMS) is a fundamental part of security defense in Smart Grid, and the communication system of WAMS is an important part of Electric power communication network. For a large regional network is concerned, the real-time data which is transferred in the communication network of WAMS will affect the safe operation of the power grid directly. Therefore, WAMS raised higher requirements for real-time, reliability and security to its communication network. In this paper, the architecture of WASM communication network was studied according to the seven layers model of the open systems interconnection(OSI), and the network architecture was researched from all levels. We explored the media of WAMS communication network, the network communication protocol and network technology. Finally, the delay of the network were analyzed.

  15. Circular resistor networks for electrical impedance tomography with partial boundary measurements

    International Nuclear Information System (INIS)

    Borcea, L; Mamonov, A V; Druskin, V

    2010-01-01

    We introduce an algorithm for the numerical solution of electrical impedance tomography (EIT) in two dimensions, with partial boundary measurements. The algorithm is an extension of the one in Borcea et al (2008 Inverse Problems 24 035013 (31pp)) and Vasquez (2006 PhD Thesis Rice University, Houston, TX, USA) for EIT with full boundary measurements. It is based on resistor networks that arise in finite volume discretizations of the elliptic partial differential equation for the potential on so-called optimal grids that are computed as part of the problem. The grids are adaptively refined near the boundary, where we measure and expect better resolution of the images. They can be used very efficiently in inversion, by defining a reconstruction mapping that is an approximate inverse of the forward map, and acts therefore as a preconditioner in any iterative scheme that solves the inverse problem via optimization. The main result in this paper is the construction of optimal grids for EIT with partial measurements by extremal quasiconformal (Teichmüller) transformations of the optimal grids for EIT with full boundary measurements. We present the algorithm for computing the reconstruction mapping on such grids, and we illustrate its performance with numerical simulations. The results show an interesting trade-off between the resolution of the reconstruction in the domain of the solution and distortions due to artificial anisotropy induced by the distribution of the measurement points on the accessible boundary

  16. Define Project

    DEFF Research Database (Denmark)

    Munk-Madsen, Andreas

    2005-01-01

    "Project" is a key concept in IS management. The word is frequently used in textbooks and standards. Yet we seldom find a precise definition of the concept. This paper discusses how to define the concept of a project. The proposed definition covers both heavily formalized projects and informally...... organized, agile projects. Based on the proposed definition popular existing definitions are discussed....

  17. "Dermatitis" defined.

    Science.gov (United States)

    Smith, Suzanne M; Nedorost, Susan T

    2010-01-01

    The term "dermatitis" can be defined narrowly or broadly, clinically or histologically. A common and costly condition, dermatitis is underresourced compared to other chronic skin conditions. The lack of a collectively understood definition of dermatitis and its subcategories could be the primary barrier. To investigate how dermatologists define the term "dermatitis" and determine if a consensus on the definition of this term and other related terms exists. A seven-question survey of dermatologists nationwide was conducted. Of respondents (n  =  122), half consider dermatitis to be any inflammation of the skin. Nearly half (47.5%) use the term interchangeably with "eczema." Virtually all (> 96%) endorse the subcategory "atopic" under the terms "dermatitis" and "eczema," but the subcategories "contact," "drug hypersensitivity," and "occupational" are more highly endorsed under the term "dermatitis" than under the term "eczema." Over half (55.7%) personally consider "dermatitis" to have a broad meaning, and even more (62.3%) believe that dermatologists as a whole define the term broadly. There is a lack of consensus among experts in defining dermatitis, eczema, and their related subcategories.

  18. Design and Development of a Pressure Transmitter Using Modified Inductance Measuring Network and Bellow Sensor

    OpenAIRE

    Venkata Lakshmi Narayana K.; Bhujanga Rao A.

    2013-01-01

    In this paper, a pressure transmitter using a modified op-amp based network for inductance measurement using a bellow as sensor has been proposed to measure the pressure and to convert pressure changes in to an electrical current which can be transmitted to a remote indicator. The change in inductance due to change in pressure is measured by an improved modified operational amplifier based network. The proposed network permits offset inductance compensation of sensing coil and also minimizes ...

  19. Comparison of Neural Network Error Measures for Simulation of Slender Marine Structures

    DEFF Research Database (Denmark)

    Christiansen, Niels H.; Voie, Per Erlend Torbergsen; Winther, Ole

    2014-01-01

    Training of an artificial neural network (ANN) adjusts the internal weights of the network in order to minimize a predefined error measure. This error measure is given by an error function. Several different error functions are suggested in the literature. However, the far most common measure...

  20. Physiological measurement platform using wireless network with Android application

    Directory of Open Access Journals (Sweden)

    Swagata Devi

    Full Text Available Currently, many people suffer from arrhythmia or hypoxia, which are abnormal health conditions. Arrhythmia occurs when a person has an irregular or abnormal heart rate, while hypoxia is realized when there is a deficiency in oxygen reaching the tissues. When a person suffers from arrhythmia, there is the possibility that the person has cardiovascular disease. A low oxygen level eventually leads to organ failure, which can result in death. To prevent such conditions, a mobile physiological measurement platform has been proposed in this paper. This system will continuously monitor the heart rate and the oxygen level of a patient. The proposed system is mainly beneficial because the medical staff or the caregiver can provide care to patients without being in close proximity. In this way, multiple numbers of patients can be treated by the physician at the same time. In this paper, two main physiological signals: the electrocardiogram (ECG and the photoplethysmogram (PPG are recorded, to measure the heart rate (in beats per minute and the peripheral capillary oxygen saturation level or SpO2 (in percentage of the patient. This is done by using a convenient graphical user interface (GUI in the Matrix Laboratory (MATLAB. Pre-processing of the bio-medical signals is done in the GUI and the calculated results are saved as text files in the current directory of MATLAB. We further propose an Android application, which will display the physiological parameters after the text files have been accessed via a wireless network. The heart rate and the oxygen level can both be monitored via this application. In case the results show an abnormal reading, the physician is notified immediately via text messaging. Keywords: ECG, PPG, SpO2, GUI, MATLAB, Android, Android App

  1. A Bayesian Approach to Measurement Bias in Networking Studies

    NARCIS (Netherlands)

    Zhu, Ling; Robinson, Scott E.; Torenvlied, René

    2014-01-01

    The study of managerial networking has been growing in the field of public administration; a field that analyzes how managers in open system organizations interact with different external actors and organizations. Coincident with this interest in managerial networking is the use of self-reported

  2. GFT centrality: A new node importance measure for complex networks

    Science.gov (United States)

    Singh, Rahul; Chakraborty, Abhishek; Manoj, B. S.

    2017-12-01

    Identifying central nodes is very crucial to design efficient communication networks or to recognize key individuals of a social network. In this paper, we introduce Graph Fourier Transform Centrality (GFT-C), a metric that incorporates local as well as global characteristics of a node, to quantify the importance of a node in a complex network. GFT-C of a reference node in a network is estimated from the GFT coefficients derived from the importance signal of the reference node. Our study reveals the superiority of GFT-C over traditional centralities such as degree centrality, betweenness centrality, closeness centrality, eigenvector centrality, and Google PageRank centrality, in the context of various arbitrary and real-world networks with different degree-degree correlations.

  3. Defining chaos.

    Science.gov (United States)

    Hunt, Brian R; Ott, Edward

    2015-09-01

    In this paper, we propose, discuss, and illustrate a computationally feasible definition of chaos which can be applied very generally to situations that are commonly encountered, including attractors, repellers, and non-periodically forced systems. This definition is based on an entropy-like quantity, which we call "expansion entropy," and we define chaos as occurring when this quantity is positive. We relate and compare expansion entropy to the well-known concept of topological entropy to which it is equivalent under appropriate conditions. We also present example illustrations, discuss computational implementations, and point out issues arising from attempts at giving definitions of chaos that are not entropy-based.

  4. Completely random measures for modelling block-structured sparse networks

    DEFF Research Database (Denmark)

    Herlau, Tue; Schmidt, Mikkel Nørgaard; Mørup, Morten

    2016-01-01

    Many statistical methods for network data parameterize the edge-probability by attributing latent traits to the vertices such as block structure and assume exchangeability in the sense of the Aldous-Hoover representation theorem. Empirical studies of networks indicate that many real-world networks...... have a power-law distribution of the vertices which in turn implies the number of edges scale slower than quadratically in the number of vertices. These assumptions are fundamentally irreconcilable as the Aldous-Hoover theorem implies quadratic scaling of the number of edges. Recently Caron and Fox...

  5. Measuring effectiveness of a university by a parallel network DEA model

    Science.gov (United States)

    Kashim, Rosmaini; Kasim, Maznah Mat; Rahman, Rosshairy Abd

    2017-11-01

    Universities contribute significantly to the development of human capital and socio-economic improvement of a country. Due to that, Malaysian universities carried out various initiatives to improve their performance. Most studies have used the Data Envelopment Analysis (DEA) model to measure efficiency rather than effectiveness, even though, the measurement of effectiveness is important to realize how effective a university in achieving its ultimate goals. A university system has two major functions, namely teaching and research and every function has different resources based on its emphasis. Therefore, a university is actually structured as a parallel production system with its overall effectiveness is the aggregated effectiveness of teaching and research. Hence, this paper is proposing a parallel network DEA model to measure the effectiveness of a university. This model includes internal operations of both teaching and research functions into account in computing the effectiveness of a university system. In literature, the graduate and the number of program offered are defined as the outputs, then, the employed graduates and the numbers of programs accredited from professional bodies are considered as the outcomes for measuring the teaching effectiveness. Amount of grants is regarded as the output of research, while the different quality of publications considered as the outcomes of research. A system is considered effective if only all functions are effective. This model has been tested using a hypothetical set of data consisting of 14 faculties at a public university in Malaysia. The results show that none of the faculties is relatively effective for the overall performance. Three faculties are effective in teaching and two faculties are effective in research. The potential applications of the parallel network DEA model allow the top management of a university to identify weaknesses in any functions in their universities and take rational steps for improvement.

  6. Directed weighted network structure analysis of complex impedance measurements for characterizing oil-in-water bubbly flow.

    Science.gov (United States)

    Gao, Zhong-Ke; Dang, Wei-Dong; Xue, Le; Zhang, Shan-Shan

    2017-03-01

    Characterizing the flow structure underlying the evolution of oil-in-water bubbly flow remains a contemporary challenge of great interests and complexity. In particular, the oil droplets dispersing in a water continuum with diverse size make the study of oil-in-water bubbly flow really difficult. To study this issue, we first design a novel complex impedance sensor and systematically conduct vertical oil-water flow experiments. Based on the multivariate complex impedance measurements, we define modalities associated with the spatial transient flow structures and construct modality transition-based network for each flow condition to study the evolution of flow structures. In order to reveal the unique flow structures underlying the oil-in-water bubbly flow, we filter the inferred modality transition-based network by removing the edges with small weight and resulting isolated nodes. Then, the weighted clustering coefficient entropy and weighted average path length are employed for quantitatively assessing the original network and filtered network. The differences in network measures enable to efficiently characterize the evolution of the oil-in-water bubbly flow structures.

  7. Defining Cyberbullying.

    Science.gov (United States)

    Englander, Elizabeth; Donnerstein, Edward; Kowalski, Robin; Lin, Carolyn A; Parti, Katalin

    2017-11-01

    Is cyberbullying essentially the same as bullying, or is it a qualitatively different activity? The lack of a consensual, nuanced definition has limited the field's ability to examine these issues. Evidence suggests that being a perpetrator of one is related to being a perpetrator of the other; furthermore, strong relationships can also be noted between being a victim of either type of attack. It also seems that both types of social cruelty have a psychological impact, although the effects of being cyberbullied may be worse than those of being bullied in a traditional sense (evidence here is by no means definitive). A complicating factor is that the 3 characteristics that define bullying (intent, repetition, and power imbalance) do not always translate well into digital behaviors. Qualities specific to digital environments often render cyberbullying and bullying different in circumstances, motivations, and outcomes. To make significant progress in addressing cyberbullying, certain key research questions need to be addressed. These are as follows: How can we define, distinguish between, and understand the nature of cyberbullying and other forms of digital conflict and cruelty, including online harassment and sexual harassment? Once we have a functional taxonomy of the different types of digital cruelty, what are the short- and long-term effects of exposure to or participation in these social behaviors? What are the idiosyncratic characteristics of digital communication that users can be taught? Finally, how can we apply this information to develop and evaluate effective prevention programs? Copyright © 2017 by the American Academy of Pediatrics.

  8. Measuring sustainable accessibility potential using the mobility infrastructure's network configuration

    NARCIS (Netherlands)

    Gil, J.; Read, S.

    2012-01-01

    This paper is an exploration into the analysis of public transport networks using space syntax approaches combined with concepts of sustainable accessibility. Present urban development policy aims to achieve sustainable mobility patterns, shifting mobility to soft transportation modes such as

  9. Valuation of measurement data for low voltage network expansion planning

    NARCIS (Netherlands)

    Nijhuis, M.; Gibescu, M.; Cobben, J.F.G.

    2017-01-01

    The introduction of electric vehicles and photovoltaics is changing the residential electricity consumption. Distribution network operators (DNO) are investing in an advanced metering infrastructure (AMI) to enable cost reduction through smart grid applications. The DNO also benefits from the

  10. Air Quality Measures on the National Environmental Health Tracking Network

    Data.gov (United States)

    U.S. Department of Health & Human Services — The Environmental Protection Agency (EPA) provides air pollution data about ozone and particulate matter (PM2.5) to CDC for the Tracking Network. The EPA maintains a...

  11. Software network analyzer for computer network performance measurement planning over heterogeneous services in higher educational institutes

    OpenAIRE

    Ismail, Mohd Nazri

    2009-01-01

    In 21st century, convergences of technologies and services in heterogeneous environment have contributed multi-traffic. This scenario will affect computer network on learning system in higher educational Institutes. Implementation of various services can produce different types of content and quality. Higher educational institutes should have a good computer network infrastructure to support usage of various services. The ability of computer network should consist of i) higher bandwidth; ii) ...

  12. Testing the Feasibility of a Low-Cost Network Performance Measurement Infrastructure

    Energy Technology Data Exchange (ETDEWEB)

    Chevalier, Scott [Indiana Univ., Bloomington, IN (United States). International Networks; Schopf, Jennifer M. [Indiana Univ., Bloomington, IN (United States). International Networks; Miller, Kenneth [Pennsylvania State Univ., University Park, PA (United States). Telecommunications and Networking Services; Zurawski, Jason [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Energy Sciences Network

    2016-07-01

    Todays science collaborations depend on reliable, high performance networks, but monitoring the end-to-end performance of a network can be costly and difficult. The most accurate approaches involve using measurement equipment in many locations, which can be both expensive and difficult to manage due to immobile or complicated assets. The perfSONAR framework facilitates network measurement making management of the tests more reasonable. Traditional deployments have used over-provisioned servers, which can be expensive to deploy and maintain. As scientific network uses proliferate, there is a desire to instrument more facets of a network to better understand trends. This work explores low cost alternatives to assist with network measurement. Benefits include the ability to deploy more resources quickly, and reduced capital and operating expenditures. Finally, we present candidate platforms and a testing scenario that evaluated the relative merits of four types of small form factor equipment to deliver accurate performance measurements.

  13. Evaluation of Techniques to Detect Significant Network Performance Problems using End-to-End Active Network Measurements

    Energy Technology Data Exchange (ETDEWEB)

    Cottrell, R.Les; Logg, Connie; Chhaparia, Mahesh; /SLAC; Grigoriev, Maxim; /Fermilab; Haro, Felipe; /Chile U., Catolica; Nazir, Fawad; /NUST, Rawalpindi; Sandford, Mark

    2006-01-25

    End-to-End fault and performance problems detection in wide area production networks is becoming increasingly hard as the complexity of the paths, the diversity of the performance, and dependency on the network increase. Several monitoring infrastructures are built to monitor different network metrics and collect monitoring information from thousands of hosts around the globe. Typically there are hundreds to thousands of time-series plots of network metrics which need to be looked at to identify network performance problems or anomalous variations in the traffic. Furthermore, most commercial products rely on a comparison with user configured static thresholds and often require access to SNMP-MIB information, to which a typical end-user does not usually have access. In our paper we propose new techniques to detect network performance problems proactively in close to realtime and we do not rely on static thresholds and SNMP-MIB information. We describe and compare the use of several different algorithms that we have implemented to detect persistent network problems using anomalous variations analysis in real end-to-end Internet performance measurements. We also provide methods and/or guidance for how to set the user settable parameters. The measurements are based on active probes running on 40 production network paths with bottlenecks varying from 0.5Mbits/s to 1000Mbit/s. For well behaved data (no missed measurements and no very large outliers) with small seasonal changes most algorithms identify similar events. We compare the algorithms' robustness with respect to false positives and missed events especially when there are large seasonal effects in the data. Our proposed techniques cover a wide variety of network paths and traffic patterns. We also discuss the applicability of the algorithms in terms of their intuitiveness, their speed of execution as implemented, and areas of applicability. Our encouraging results compare and evaluate the accuracy of our

  14. Energy and Power Measurements for Network Coding in the Context of Green Mobile Clouds

    DEFF Research Database (Denmark)

    Paramanathan, Achuthan; Pedersen, Morten Videbæk; Roetter, Daniel Enrique Lucani

    2013-01-01

    results for inter-session network coding in Open-Mesh routers underline that the energy invested in performing network coding pays off by dramatically reducing the total energy for the transmission of data over wireless links. We also show measurements for intra-session network coding in three different......This paper presents an in-depth power and energy measurement campaign for inter- and intra-session network coding enabled communication in mobile clouds. The measurements are carried out on different commercial platforms with focus on routers and mobile phones with different CPU capabilities. Our...

  15. How Not to Evaluate a Psychological Measure: Rebuttal to Criticism of the Defining Issues Test of Moral Judgment Development by Curzer and Colleagues

    Science.gov (United States)

    Thoma, Stephen J.; Bebeau, Muriel J.; Narvaez, Darcia

    2016-01-01

    In a 2014 paper in "Theory and Research in Education," Howard Curzer and colleagues critique the Defining Issues Test of moral judgment development according to eight criteria that are described as difficulties any measure of educational outcomes must address. This article highlights how Curzer et al. do not consult existing empirical…

  16. Defining Glaucomatous Optic Neuropathy from a Continuous Measure of Optic Nerve Damage - The Optimal Cut-off Point for Risk-factor Analysis in Population-based Epidemiology

    NARCIS (Netherlands)

    Ramdas, Wishal D.; Rizopoulos, Dimitris; Wolfs, Roger C. W.; Hofman, Albert; de Jong, Paulus T. V. M.; Vingerling, Johannes R.; Jansonius, Nomdo M.

    2011-01-01

    Purpose: Diseases characterized by a continuous trait can be defined by setting a cut-off point for the disease measure in question, accepting some misclassification. The 97.5th percentile is commonly used as a cut-off point. However, it is unclear whether this percentile is the optimal cut-off

  17. Four Years of Chemical Measurements from the Deepwater Horizon Oil Spill Define the Deep Sea Sediment footprint and Subsequent Recovery

    Science.gov (United States)

    Boehm, P.

    2016-02-01

    Chemical data acquired during and after the DWHOS showed that several mechanisms were responsible for transport of oil from the water column to the sediments in the deep sea off the continental shelf. Three primary pathways were identified:Sorption onto and sinking of drilling mud particles during "Top Kill" response activity, highly scattered deposition of residuesfrom in situ burns, and deposition of oil combined with microbial organic matter from diffuse oil plumes ("marine snow"). Data collected during 2010, 2011 and 2014 were used to define the oil footprint and estimate time to recovery. More than 1200 stations were sampled. Of these, 27 stations were visited all three years, providing a time series from which recovery rates were calculated using the loss of total polycyclic aromatic hydrocarbons (TPAH) over time fit to first order kinetics. Results showed that the footprint of the oil was limited to the area around the wellhead and in patches to the southwest. Mostsamples had returned to background levels by 2015, with some exceptions close to the wellhead. Deposition to the northeast (DeSoto Canyon) was minor as evidenced by the absence of oil in sediments in that area. Samples with the longest recovery times were within 2 nautical miles of the wellhead, and often contained drilling mud, as shown by olefin signatures on the GC/FID chromatogram. Detailed chemistry data evaluation and chemical fingerprinting provided evidence that oil was being degraded in situ.

  18. Improved measurements of scant hydrogen peroxide enable experiments that define its threshold of toxicity for Escherichia coli.

    Science.gov (United States)

    Li, Xin; Imlay, James A

    2018-03-14

    Escherichia coli is a model organism that has been exploited to reveal key details of hydrogen peroxide stress: the biomolecules that H 2 O 2 most rapidly damages and the defensive tactics that organisms use to fend it off. Much less clear is the amount of exogenous H 2 O 2 that is sufficient to injure the bacterium and/or to trigger its stress response. To fill this gap, we need to study the behavior of cells when they are exposed to defined amounts of H 2 O 2 on an hours-long time scale. Such experiments are difficult because bacteria rapidly consume H 2 O 2 that is added to test cultures. Further, lab media itself can generate H 2 O 2 , and media components interfere with the quantification of H 2 O 2 levels. In this study we describe mechanisms by which media components interfere with H 2 O 2 determinations, and we identify simple ways to minimize and correct for this interference. Using these techniques, it was shown that standard media generate so much H 2 O 2 that most intracellular H 2 O 2 derives from the medium rather than from endogenous metabolism. Indeed, bacteria spread on plates must induce their stress response or else perish. Finally, two straightforward methods were used to sustain low-micromolar steady-state concentrations of H 2 O 2 . In this way we determined that > 2 μM extracellular H 2 O 2 is sufficient to trigger the intracellular OxyR stress response, and > 5 μM begins to impair cell growth in a minimal medium. These concentrations are orders of magnitude lower than the doses that have typically been used in lab experiments. The new approaches should enable workers to study how various organisms cope with natural levels of H 2 O 2 stress. Copyright © 2018 Elsevier Inc. All rights reserved.

  19. Value for money: Defining and measuring 'value' in MoD's acquisition policy of obtaining best value for money

    OpenAIRE

    Weiss, A.

    2006-01-01

    Obtaining value for money is a keystone of UK Ministry of Defence (MoD) acquisition strategy embedded in its Smart Acquisition policy. This thesis examines how best to measure the relative value of competing tender submissions for major projects. There is a comprehensive discussion of a wide range of relevant definitions and over three dozen documents are scrutinised including just some sixteen published by the Government. Commercially available models, algorithms and software are examined as...

  20. Developing a patient-centered outcome measure for complementary and alternative medicine therapies I: defining content and format

    Directory of Open Access Journals (Sweden)

    Ritenbaugh Cheryl

    2011-12-01

    Full Text Available Abstract Background Patients receiving complementary and alternative medicine (CAM therapies often report shifts in well-being that go beyond resolution of the original presenting symptoms. We undertook a research program to develop and evaluate a patient-centered outcome measure to assess the multidimensional impacts of CAM therapies, utilizing a novel mixed methods approach that relied upon techniques from the fields of anthropology and psychometrics. This tool would have broad applicability, both for CAM practitioners to measure shifts in patients' states following treatments, and conventional clinical trial researchers needing validated outcome measures. The US Food and Drug Administration has highlighted the importance of valid and reliable measurement of patient-reported outcomes in the evaluation of conventional medical products. Here we describe Phase I of our research program, the iterative process of content identification, item development and refinement, and response format selection. Cognitive interviews and psychometric evaluation are reported separately. Methods From a database of patient interviews (n = 177 from six diverse CAM studies, 150 interviews were identified for secondary analysis in which individuals spontaneously discussed unexpected changes associated with CAM. Using ATLAS.ti, we identified common themes and language to inform questionnaire item content and wording. Respondents' language was often richly textured, but item development required a stripping down of language to extract essential meaning and minimize potential comprehension barriers across populations. Through an evocative card sort interview process, we identified those items most widely applicable and covering standard psychometric domains. We developed, pilot-tested, and refined the format, yielding a questionnaire for cognitive interviews and psychometric evaluation. Results The resulting questionnaire contained 18 items, in visual analog scale format

  1. Measurements of Voltage Harmonics in 400 kV Transmission Network

    Directory of Open Access Journals (Sweden)

    Ryszard Pawełek

    2014-06-01

    Full Text Available The paper deals with the analysis of voltage harmonics measurements performed in the 400 kV transmission network. The voltage was measured by means of three transducers: resistive voltage divider, inductive measuring transformer and capacitive voltage measuring transformer. Instrument errors were estimated for measuring transformers with reference to the harmonic values obtained from the voltage divider.

  2. Talking and learning physics: Predicting future grades from network measures and Force Concept Inventory pretest scores

    Directory of Open Access Journals (Sweden)

    Jesper Bruun

    2013-07-01

    Full Text Available The role of student interactions in learning situations is a foundation of sociocultural learning theory, and social network analysis can be used to quantify student relations. We discuss how self-reported student interactions can be viewed as processes of meaning making and use this to understand how quantitative measures that describe the position in a network, called centrality measures, can be understood in terms of interactions that happen in the context of a university physics course. We apply this discussion to an empirical data set of self-reported student interactions. In a weekly administered survey, first year university students enrolled in an introductory physics course at a Danish university indicated with whom they remembered having communicated within different interaction categories. For three categories pertaining to (1 communication about how to solve physics problems in the course (called the PS category, (2 communications about the nature of physics concepts (called the CD category, and (3 social interactions that are not strictly related to the content of the physics classes (called the ICS category in the introductory mechanics course, we use the survey data to create networks of student interaction. For each of these networks, we calculate centrality measures for each student and correlate these measures with grades from the introductory course, grades from two subsequent courses, and the pretest Force Concept Inventory (FCI scores. We find highly significant correlations (p<0.001 between network centrality measures and grades in all networks. We find the highest correlations between network centrality measures and future grades. In the network composed of interactions regarding problem solving (the PS network, the centrality measures hide and PageRank show the highest correlations (r=-0.32 and r=0.33, respectively with future grades. In the CD network, the network measure target entropy shows the highest correlation

  3. Ultrasensitive prostate specific antigen assay following laparoscopic radical prostatectomy--an outcome measure for defining the learning curve.

    Science.gov (United States)

    Viney, R; Gommersall, L; Zeif, J; Hayne, D; Shah, Z H; Doherty, A

    2009-07-01

    Radical retropubic prostatectomy (RRP) performed laparoscopically is a popular treatment with curative intent for organ-confined prostate cancer. After surgery, prostate specific antigen (PSA) levels drop to low levels which can be measured with ultrasensitive assays. This has been described in the literature for open RRP but not for laparoscopic RRP. This paper describes PSA changes in the first 300 consecutive patients undergoing non-robotic laparoscopic RRP by a single surgeon. To use ultrasensitive PSA (uPSA) assays to measure a PSA nadir in patients having laparoscopic radical prostatectomy below levels recorded by standard assays. The aim was to use uPSA nadir at 3 months' post-prostatectomy as an early surrogate end-point of oncological outcome. In so doing, laparoscopic oncological outcomes could then be compared with published results from other open radical prostatectomy series with similar end-points. Furthermore, this end-point could be used in the assessment of the surgeon's learning curve. Prospective, comprehensive, demographic, clinical, biochemical and operative data were collected from all patients undergoing non-robotic laparoscopic RRP. We present data from the first 300 consecutive patients undergoing laparoscopic RRP by a single surgeon. uPSA was measured every 3 months post surgery. Median follow-up was 29 months (minimum 3 months). The likelihood of reaching a uPSA of bench-marking performance. With experience, a surgeon can achieve in excess of an 80% chance of obtaining a uPSA nadir of < or = 0.01 ng/ml at 3 months after laparoscopic RRP for a British population. This is equivalent to most published open series.

  4. Quantum Measurements: From Bayes Rule to Neural Networks

    DEFF Research Database (Denmark)

    Greplova, Eliska

    2017-01-01

    Quantum technologies are becoming more and more introduced into the devices that we use in the daily life, such as quantum dot based television screens or quantum cryptographic channels for encoding financial transactions. Given the limits of the silicon computer chips, it will in the near future...... learning techniques such as artificial neural networks....

  5. A Newly Developed Method for Computing Reliability Measures in a Water Supply Network

    Directory of Open Access Journals (Sweden)

    Jacek Malinowski

    2016-01-01

    Full Text Available A reliability model of a water supply network has beens examined. Its main features are: a topology that can be decomposed by the so-called state factorization into a (relativelysmall number of derivative networks, each having a series-parallel structure (1, binary-state components (either operative or failed with given flow capacities (2, a multi-state character of the whole network and its sub-networks - a network state is defined as the maximal flow between a source (sources and a sink (sinks (3, all capacities (component, network, and sub-network have integer values (4. As the network operates, its state changes due to component failures, repairs, and replacements. A newly developed method of computing the inter-state transition intensities has been presented. It is based on the so-called state factorization and series-parallel aggregation. The analysis of these intensities shows that the failure-repair process of the considered system is an asymptotically homogenous Markov process. It is also demonstrated how certain reliability parameters useful for the network maintenance planning can be determined on the basis of the asymptotic intensities. For better understanding of the presented method, an illustrative example is given. (original abstract

  6. Facing a Problem of Electrical Energy Quality in Ship Networks-measurements, Estimation, Control

    Institute of Scientific and Technical Information of China (English)

    Tomasz Tarasiuk; Janusz Mindykowski; Xiaoyan Xu

    2003-01-01

    In this paper, electrical energy quality and its indices in ship electric networks are introduced, especially the meaning of electrical energy quality terms in voltage and active and reactive power distribution indices. Then methods of measurement of marine electrical energy indices are introduced in details and a microprocessor measurement-diagnosis system with the function of measurement and control is designed. Afterwards, estimation and control of electrical power quality of marine electrical power networks are introduced. And finally, according to the existing method of measurement and control of electrical power quality in ship power networks, the improvement of relative method is proposed.

  7. Sweeping the Floor or Putting a Man on the Moon: How to Define and Measure Meaningful Work.

    Science.gov (United States)

    Both-Nwabuwe, Jitske M C; Dijkstra, Maria T M; Beersma, Bianca

    2017-01-01

    Meaningful work is integral to well-being and a flourishing life. The construct of "meaningful work" is, however, consistently affected by conceptual ambiguity. Although there is substantial support for arguments to maintain the status of conceptual ambiguity, we make a case for the benefits of having consensus on a definition and scale of meaningful work in the context of paid work. The objective of this article, therefore, was twofold. Firstly, we wanted to develop a more integrative definition of meaningful work. Secondly, we wanted to establish a corresponding operationalization. We reviewed the literature on the existing definitions of meaningful work and the scales designed to measure it. We found 14 definitions of meaningful work. Based on these definitions, we identified four categories of definitions, which led us to propose an integrative and comprehensive definition of meaningful work. We identified two validated scales that were partly aligned with the proposed definition. Based on our review, we conclude that scholars in this field should coalesce rather than diverge their efforts to conceptualize and measure meaningful work.

  8. Network cohesion

    OpenAIRE

    Cavalcanti, Tiago V. V.; Giannitsarou, Chryssi; Johnson, Charles R.

    2016-01-01

    This is the final version of the article. It first appeared from Springer via http://dx.doi.org/10.1007/s00199-016-0992-1 We define a measure of network cohesion and show how it arises naturally in a broad class of dynamic models of endogenous perpetual growth with network externalities. Via a standard growth model, we show why network cohesion is crucial for conditional convergence and explain that as cohesion increases, convergence is faster. We prove properties of network cohesion and d...

  9. An Attractor-Based Complexity Measurement for Boolean Recurrent Neural Networks

    Science.gov (United States)

    Cabessa, Jérémie; Villa, Alessandro E. P.

    2014-01-01

    We provide a novel refined attractor-based complexity measurement for Boolean recurrent neural networks that represents an assessment of their computational power in terms of the significance of their attractor dynamics. This complexity measurement is achieved by first proving a computational equivalence between Boolean recurrent neural networks and some specific class of -automata, and then translating the most refined classification of -automata to the Boolean neural network context. As a result, a hierarchical classification of Boolean neural networks based on their attractive dynamics is obtained, thus providing a novel refined attractor-based complexity measurement for Boolean recurrent neural networks. These results provide new theoretical insights to the computational and dynamical capabilities of neural networks according to their attractive potentialities. An application of our findings is illustrated by the analysis of the dynamics of a simplified model of the basal ganglia-thalamocortical network simulated by a Boolean recurrent neural network. This example shows the significance of measuring network complexity, and how our results bear new founding elements for the understanding of the complexity of real brain circuits. PMID:24727866

  10. Measurements for the production of aluminium oxide ceramics with defined microstructure parameters by using colloidal-chemical processings

    International Nuclear Information System (INIS)

    Baer, D.; Foerthmann, R.; Naoumidis, A.; Nickel, H.

    1992-04-01

    The aim of this work is to verify the influences of the different single procedure steps on the microstructure of sintered alumina and to get a correlation between the product characteristics and the characteristic data. The powder production was carried out by using the sol-gel-process followed by freeze-drying of the gel. From the boehmit-powder porous and inhomogen microstructure of the sintered pellets was obtained. The unfavourable morphology of the hydroxide-powder could be eliminated by pre-calcination followed by powder-milling. Because of the wet-milling after the pre-calcination the powder was doped with α-Al 2 O 3 , caused by the abrasion of the milling-mug and -balls, and therefore the calcinating temperature could be reduced to 1050deg C. Two charges of the colloidal-chemical produced powder and four commercial powders with different characteristics with regard to the purity or doping and particle-size and -distribution were compared with themselves. These powders were cold-isostatically pressed and sintered under different conditions. It could be shown that the influence of the impurities on the microstructure is higher than the influence of the grain size distribution. Impurities lead to a discontinous grain size distribution and intracristalline pores in sintered bodies, even using powders with a small grain size distribution. Measurements on the slip casted samples yielded for all powders different relationships between the viscosity and the pH. There was no visible influence of different pH-values on the microstructure (pH always measured at the minimum of the viscosity). Here the influence of the purity and the grain size distribution on the microstructure was less pronounced compared with the isostatically pressed ceramics. (orig.) [de

  11. Defining adolescent common mental disorders using electronic primary care data: a comparison with outcomes measured using the CIS-R.

    Science.gov (United States)

    Cornish, Rosie P; John, Ann; Boyd, Andy; Tilling, Kate; Macleod, John

    2016-12-01

    To compare the prevalence of common mental disorders (CMDs) derived from data held in primary care records with that measured using the revised Clinical Interview Schedule (CIS-R) in order to assess the potential robustness of findings based only on routinely collected data. Comparison study using linkage between the Avon Longitudinal Study of Parents and Children (ALSPAC) and electronic primary care records. We studied 1562 adolescents who had completed the CIS-R in ALSPAC at age 17-18 years and had linkage established to their primary care records. Outcome measures from ALSPAC were whether or not an individual met International Classification of Diseases-10 criteria for a diagnosis of (1) a CMD or, specifically, (2) depression. Lists of Read codes corresponding to diagnoses, symptoms and treatments were used to create 12 definitions of CMD and depression alone using the primary care data. We calculated sensitivities and specificities of these, using CIS-R definitions as the reference standard. Sensitivities ranged from 5.2% to 24.3% for depression and from 3.8% to 19.2% for CMD. The specificities of all definitions were above 98% for depression and above 96% for CMD.For both outcomes, the definition that included current diagnosis, treatment or symptoms identified the highest proportion of CIS-R cases. Most individuals meeting case definitions for CMD based on primary care data also met CIS-R case definitions. Conversely many individuals identified as cases using the CIS-R had no evidence of CMD in their clinical records. This suggests that clinical databases are likely to yield underestimates of the burden of CMD in the population. However, clinical records appear to yield valid diagnoses which may be useful for studying risk factors and consequences of CMD. The greatest epidemiological value may be obtained when information is available from survey and clinical records. Published by the BMJ Publishing Group Limited. For permission to use (where not already

  12. Defining greed.

    Science.gov (United States)

    Seuntjens, Terri G; Zeelenberg, Marcel; Breugelmans, Seger M; van de Ven, Niels

    2015-08-01

    Although greed is both hailed as the motor of economic growth and blamed as the cause of economic crises, very little is known about its psychological underpinnings. Five studies explored lay conceptualizations of greed among U.S. and Dutch participants using a prototype analysis. Study 1 identified features related to greed. Study 2 determined the importance of these features; the most important features were classified as central (e.g., self-interested, never satisfied), whereas less important features were classified as peripheral (e.g., ambition, addiction). Subsequently, we found that, compared to peripheral features, participants recalled central features better (Study 3), faster (Study 4), and these central features were more present in real-life episodes of greed (Study 5). These findings provide a better understanding of the elements that make up the experience of greed and provide insights into how greed can be manipulated and measured in future research. © 2014 The British Psychological Society.

  13. Measuring the Influence of Efficient Ports using Social Network Metrics

    Directory of Open Access Journals (Sweden)

    Byung-Hak Leem

    2015-02-01

    Full Text Available Data envelopment analysis (DEA is known as a useful tool that produces many efficient decision-making units (DMUs. Traditional DEA provides relative efficient scores and reference sets, but does not influence and rank the efficient DMUs. This paper suggests a method that provides influence and ranking information by using PageRank as a centrality of Social Network analysis (SNA based on reference sets and their lambda values. The social network structure expresses the DMU as a node, reference sets as link, and lambda as connection strengths or weights. This paper, with PageRank, compares the Eigenvector centrality suggested by Liu, et al. in 2009, and shows that PageRank centrality is more accurate.

  14. Measuring Customer Behavior with Deep Convolutional Neural Networks

    Directory of Open Access Journals (Sweden)

    Veaceslav Albu

    2016-03-01

    Full Text Available In this paper, we propose a neural network model for human emotion and gesture classification. We demonstrate that the proposed architecture represents an effective tool for real-time processing of customer's behavior for distributed on-land systems, such as information kiosks, automated cashiers and ATMs. The proposed approach combines most recent biometric techniques with the neural network approach for real-time emotion and behavioral analysis. In the series of experiments, emotions of human subjects were recorded, recognized, and analyzed to give statistical feedback of the overall emotions of a number of targets within a certain time frame. The result of the study allows automatic tracking of user’s behavior based on a limited set of observations.

  15. Basic security measures for IEEE 802.11 wireless networks

    Directory of Open Access Journals (Sweden)

    Oscar P. Sarmiento

    2008-05-01

    Full Text Available This article presents a tutorial/discussion of three commonly-used IEEE 802.11 wireless network security standards: WEP, WPA and WPA2. A detailed analysis of the RC4 algorithm supporting WEP is presented, including its vulnera-bilities. The WPA and WPA2 encryption protocols’ most relevant aspects and technical characteristics are reviewed for a comparative analysis of the three standards in terms of the security they provide. Special attention has been paid to WEP encryption by using an educational simulation tool written in C++ Builder for facilitating the unders-tanding of this protocol at academic level. Two practical cases of wireless security configurations using Cisco net-working equipment are also presented: configuring and enabling WPA-Personal and WPA2-Personal (these being security options used by TKIP and AES, respectively.

  16. Basic security measures for IEEE 802.11 wireless networks

    OpenAIRE

    Sarmiento, Oscar P.; Guerrero, Fabio G.; Rey Argote, David

    2008-01-01

    This article presents a tutorial/discussion of three commonly-used IEEE 802.11 wireless network security standards: WEP, WPA and WPA2. A detailed analysis of the RC4 algorithm supporting WEP is presented, including its vulnerabilities. The WPA and WPA2 encryption protocols’ most relevant aspects and technical characteristics are reviewed for a comparative analysis of the three standards in terms of the security they provide. Special attention has been paid to WEP encryption by using an educat...

  17. Initial steps in defining the environment of the prepuce of the bull by measuring pH and temperature.

    Science.gov (United States)

    Koziol, J H; Fraser, N S; Passler, T; Wolfe, D F

    2017-12-01

    To determine the baseline pH and temperature of the preputial cavity of bulls. We enrolled 55 bulls ranging in age from 15 to 84 months. The preputial temperature and pH were measured by insertion of temperature and pH probes, respectively, into the preputial orifice prior to routine breeding soundness examinations. Information was obtained from owners regarding the diet of each bull and categorised as one of three categories: forage only, grain supplemented or silage supplemented. The average temperature of the prepuce was 37.81°C ± 1.76 and the median pH of the prepuce was 8.45 (6.35-9.46). Preputial temperatures of the bull weakly correlated with ambient temperatures (r s  = -0.29, P = 0.028). The preputial pH of silage-fed bulls was significantly lower than that of bulls fed forage only (P = 0.025) or grain-supplemented diets (P = 0.002). The median preputial pH of bulls fed a silage-based diet was 7.6 (6.3-8.9) compared with a median pH 8.7 (7.8-9.1) for bulls fed forage-based diets or a median of 8.5 (7.7-9.4) for those given grain-supplemented diets. Diet and ambient temperature can, respectively, affect pH and the temperature in the prepuce. Further studies to describe and understand the microbiota of the prepuce and penis may assist in developing treatments for diseases of the genital tract in bulls. © 2017 Australian Veterinary Association.

  18. High resistance (up to 1014 ohms) measurement using RC networks

    International Nuclear Information System (INIS)

    Florescu, Valeriu

    2008-01-01

    An application of dynamic measuring techniques of resistances from 10 6 to 10 14 ohms is described. The method has been analyzed with an eye to measuring accuracy, other influences of the actual measuring circuit also being considered. In conclusion, an automatic measuring method with A/D conversion, automatic range selection, and digital output in semilogarithmic form is outlined. It has been experimentally verified that the dynamic method of resistance measurement can be used for testing insulation resistance of materials and resistors. The great advantage of the automatic measuring circuit is that, apart from an easy automatic selection of the measuring range, digital output in semilogarithmic form ensures compatibility with digital computer systems and facilitates the grading in resistor manufacture. The time required for measuring resistances of the known order of magnitude does not exceed 1 s. Automatic selection of the order of magnitude speeds up the measurement of unknown resistances. For resistance measurement over the range of 10 6 to 10 14 ohms, the measuring accuracy of 1 to 2% is usually sufficient. The meter can be designed as an inexpensive attachment to a conventional counter. The principle of integration measurement avoids undesirable interference effects with which the conventional measuring methods are afflicted. Since the measuring voltage can be adjusted continuously, even the voltage dependence of resistance can be measured

  19. Simulation and measurement of optical access network with different types of optical-fiber amplifiers

    Science.gov (United States)

    Latal, Jan; Vogl, Jan; Koudelka, Petr; Vitasek, Jan; Siska, Petr; Liner, Andrej; Papes, Martin; Vasinek, Vladimir

    2012-01-01

    The optical access networks are nowadays swiftly developing in the telecommunications field. These networks can provide higher data transfer rates, and have great potential to the future in terms of transmission possibilities. Many local internet providers responded to these facts and began gradually installing optical access networks into their originally built networks, mostly based on wireless communication. This allowed enlargement of possibilities for end-users in terms of high data rates and also new services such as Triple play, IPTV (Internet Protocol television) etc. However, with this expansion and building-up is also related the potential of reach in case of these networks. Big cities, such as Prague, Brno, Ostrava or Olomouc cannot be simply covered, because of their sizes and also because of their internal regulations given by various organizations in each city. Standard logical and also physical reach of EPON (IEEE 802.3ah - Ethernet Passive Optical Network) optical access network is about 20 km. However, for networks based on Wavelength Division Multiplex the reach can be up to 80 km, if the optical-fiber amplifier is inserted into the network. This article deals with simulation of different types of amplifiers for WDM-PON (Wavelength Division Multiplexing-Passive Optical Network) network in software application Optiwave OptiSystem and than are the values from the application and from real measurement compared.

  20. Software Defined Cyberinfrastructure

    Energy Technology Data Exchange (ETDEWEB)

    Foster, Ian; Blaiszik, Ben; Chard, Kyle; Chard, Ryan

    2017-07-17

    Within and across thousands of science labs, researchers and students struggle to manage data produced in experiments, simulations, and analyses. Largely manual research data lifecycle management processes mean that much time is wasted, research results are often irreproducible, and data sharing and reuse remain rare. In response, we propose a new approach to data lifecycle management in which researchers are empowered to define the actions to be performed at individual storage systems when data are created or modified: actions such as analysis, transformation, copying, and publication. We term this approach software-defined cyberinfrastructure because users can implement powerful data management policies by deploying rules to local storage systems, much as software-defined networking allows users to configure networks by deploying rules to switches.We argue that this approach can enable a new class of responsive distributed storage infrastructure that will accelerate research innovation by allowing any researcher to associate data workflows with data sources, whether local or remote, for such purposes as data ingest, characterization, indexing, and sharing. We report on early experiments with this approach in the context of experimental science, in which a simple if-trigger-then-action (IFTA) notation is used to define rules.

  1. Network centrality measures and systemic risk: An application to the Turkish financial crisis

    Science.gov (United States)

    Kuzubaş, Tolga Umut; Ömercikoğlu, Inci; Saltoğlu, Burak

    2014-07-01

    In this paper, we analyze the performance of several network centrality measures in detecting systemically important financial institutions (SIFI) using data from the Turkish Interbank market during the financial crisis in 2000. We employ various network investigation tools such as volume, transactions, links, connectivity and reciprocity to gain a clearer picture of the network topology of the interbank market. We study the main borrower role of Demirbank in the crash of the banking system with network centrality measures which are extensively used in the network theory. This ex-post analysis of the crisis shows that centrality measures perform well in identifying and monitoring systemically important financial institutions which provide useful insights for financial regulations.

  2. Physical and Radiological Characterisation of Measuring Sites Within The Croatian Gamma Dose Rate Early Warning Network

    International Nuclear Information System (INIS)

    Cindro, M.; Stepisnik, M.; Pinezic, D.; Sinka, D.; Skanata, D.

    2016-01-01

    The work described in this paper was done within the EU funded project 'Upgrading the systems for the on- and off-line monitoring of radioactivity in the environment in Croatia in regular and emergency situations'. The existing system of early warning in case of nuclear accident in Croatia (SPUNN), managed by the State Office for Radiological and Nuclear Safety, includes 33 stations for measuring ambient gamma dose rate (GDR). The aim of the project was to determine appropriate correction factors that will allow the results from this network to be used not only for timely warning in case of nuclear accident but also in routine environmental monitoring to determine the background radiation. Additionally, in the case of fresh deposition due to radioactive contamination, the corrected values are better suited to be used as an input for support systems for decision making in the case of emergency (such as RODOS), as well as for international data exchange (EURDEP) or automatic interpolation and mapping of radiological data (INTAMAP). The response of the individual probes to natural or accidental radiation mostly depends on the geometry or topography, surrounding buildings, vegetation (trees) and the type of soil beneath the detector. In the case of measuring the dose rate, objects such as buildings act as a shield against gamma radiation and limit the field of vision of the detector. If we want to have representative values that can be compared with other measuring sites, it is clear that we need to define standard conditions that each location has to meet. This is true not only for the probes within the same network, but can also be applied more broadly, at the international level, since data exchange mechanisms for GDR data already exist across Europe. The response of each probe is not determined only by the physical features, it is also important to understand the radiological characteristics of the site. Radiological characterization was performed through

  3. Measurement campaign on connectivity of mesh networks formed by mobile devices

    DEFF Research Database (Denmark)

    Pietrarca, Beatrice; Sasso, Giovanni; Perrucci, Gian Paolo

    2007-01-01

    This paper reports the results of a measurement campaign on the connectivity level of mobile devices using Bluetooth (BT) to form cooperative mobile mesh networks. Such mobile mesh networks composed of mobile devices are the basis for any peer-to-peer communication like wireless grids or social...

  4. Multiscale Pore Throat Network Reconstruction of Tight Porous Media Constrained by Mercury Intrusion Capillary Pressure and Nuclear Magnetic Resonance Measurements

    Science.gov (United States)

    Xu, R.; Prodanovic, M.

    2017-12-01

    Due to the low porosity and permeability of tight porous media, hydrocarbon productivity strongly depends on the pore structure. Effective characterization of pore/throat sizes and reconstruction of their connectivity in tight porous media remains challenging. Having a representative pore throat network, however, is valuable for calculation of other petrophysical properties such as permeability, which is time-consuming and costly to obtain by experimental measurements. Due to a wide range of length scales encountered, a combination of experimental methods is usually required to obtain a comprehensive picture of the pore-body and pore-throat size distributions. In this work, we combine mercury intrusion capillary pressure (MICP) and nuclear magnetic resonance (NMR) measurements by percolation theory to derive pore-body size distribution, following the work by Daigle et al. (2015). However, in their work, the actual pore-throat sizes and the distribution of coordination numbers are not well-defined. To compensate for that, we build a 3D unstructured two-scale pore throat network model initialized by the measured porosity and the calculated pore-body size distributions, with a tunable pore-throat size and coordination number distribution, which we further determine by matching the capillary pressure vs. saturation curve from MICP measurement, based on the fact that the mercury intrusion process is controlled by both the pore/throat size distributions and the connectivity of the pore system. We validate our model by characterizing several core samples from tight Middle East carbonate, and use the network model to predict the apparent permeability of the samples under single phase fluid flow condition. Results show that the permeability we get is in reasonable agreement with the Coreval experimental measurements. The pore throat network we get can be used to further calculate relative permeability curves and simulate multiphase flow behavior, which will provide valuable

  5. Study of the dose rate measured by the radiological surveillance network of the Basque country

    International Nuclear Information System (INIS)

    Alegria, N.; Legarda, F.; Herranz, M.

    2006-01-01

    Full text of publication follows: The radiological Surveillance Network of the Basque Country, which is constituted by three stations located in Bilbao, Vitoria and San Sebastian, measures and records the dose date every 10 minutes. Some environmental parameters affect the behaviour of the dose rate. One of most important meteorological parameters is rain. So, it has been necessary to study separately the behaviour of dose rate in the absence of rain, defining that time as Dry Time, and the behaviour when it rains, designating that time as Wet Time. Previous studies have confirmed that dose rate values are fitted to normal distributions, and in those cases, Critical Limits can be calculated using Curie formulation. Every January, data recorded in previous year, two Critical Limits are obtained, one of them for dry time and other one for wet time, and both together define the Alarm Level for each radiological station. That Alarm Level is the reference value for dose rate. If some dose rate value is higher than the corresponding Alarm Level, the recorded values have to be studied in order to identify the origin or the cause of that value. In most cases, in which the dose rate is higher than the corresponding Alarm Level due to precipitation, occurs that when rain stops the dose rate value does not fall immediately to dry rime values, and then the Alarm Level which is now that for dry time is exceeded by the dose rate. So, those values can be considered a special group called Transition Area. The second part of the study tries to explain the cause and the behaviour of the values in the transition Area by means of the study of the behaviour of radon daughters in the atmosphere and their deposition onto the ground during rain intervals. To check the results several situations have been simulated using the Monte Carlo code MCNP-4C. (authors)

  6. Air pollution assessment in the Slovak Republic in 2005. Measurement stations of air quality monitoring network

    International Nuclear Information System (INIS)

    Anon

    2006-05-01

    In this Appendix to the report 'Air pollution assessment in the Slovak Republic in 2005' the main characteristics of measurement stations of air quality monitoring network of the Slovak Republic are presented

  7. Air pollution assessment in the Slovak Republic in 2004. Measurement stations of air quality monitoring network

    International Nuclear Information System (INIS)

    Anon

    2005-07-01

    In this Appendix to the report 'Air pollution assessment in the Slovak Republic in 2004' the main characteristics of measurement stations of air quality monitoring network of the Slovak Republic are presented

  8. Output power distributions of mobile radio base stations based on network measurements

    International Nuclear Information System (INIS)

    Colombi, D; Thors, B; Persson, T; Törnevik, C; Wirén, N; Larsson, L-E

    2013-01-01

    In this work output power distributions of mobile radio base stations have been analyzed for 2G and 3G telecommunication systems. The approach is based on measurements in selected networks using performance surveillance tools part of the network Operational Support System (OSS). For the 3G network considered, direct measurements of output power levels were possible, while for the 2G networks, output power levels were estimated from measurements of traffic volumes. Both voice and data services were included in the investigation. Measurements were conducted for large geographical areas, to ensure good overall statistics, as well as for smaller areas to investigate the impact of different environments. For high traffic hours, the 90th percentile of the averaged output power was found to be below 65% and 45% of the available output power for the 2G and 3G systems, respectively.

  9. Output power distributions of mobile radio base stations based on network measurements

    Science.gov (United States)

    Colombi, D.; Thors, B.; Persson, T.; Wirén, N.; Larsson, L.-E.; Törnevik, C.

    2013-04-01

    In this work output power distributions of mobile radio base stations have been analyzed for 2G and 3G telecommunication systems. The approach is based on measurements in selected networks using performance surveillance tools part of the network Operational Support System (OSS). For the 3G network considered, direct measurements of output power levels were possible, while for the 2G networks, output power levels were estimated from measurements of traffic volumes. Both voice and data services were included in the investigation. Measurements were conducted for large geographical areas, to ensure good overall statistics, as well as for smaller areas to investigate the impact of different environments. For high traffic hours, the 90th percentile of the averaged output power was found to be below 65% and 45% of the available output power for the 2G and 3G systems, respectively.

  10. Defining and Measuring Teacher Legitimacy

    Science.gov (United States)

    Drake, Douglass Martin

    2013-01-01

    Power and authority exist in every relationship. The relationship between teacher and student is no exception. Legitimacy is the cornerstone of authority, yet there is a dearth of research into how teacher legitimacy affects the teacher/student relationship. In the current study, I sought to identify characteristics and behaviors teachers exhibit…

  11. Defining and Measuring User Experience

    DEFF Research Database (Denmark)

    Stage, Jan

    2006-01-01

    User experience is being used to denote what a user goes through while using a computerized system. The concept has gained momentum as a means to distinguish new types of applications such as games and entertainment software from more traditional work-related applications. This paper focuses on t...

  12. Defining and Measuring Chronic Conditions

    Centers for Disease Control (CDC) Podcasts

    This podcast is an interview with Dr. Anand Parekh, U.S. Department of Health and Human Services Deputy Assistant Secretary for Health, and Dr. Samuel Posner, Preventing Chronic Disease Editor in Chief, about the definition and burden of multiple chronic conditions in the United States.

  13. Defining and Measuring Chronic Conditions

    Centers for Disease Control (CDC) Podcasts

    2013-05-20

    This podcast is an interview with Dr. Anand Parekh, U.S. Department of Health and Human Services Deputy Assistant Secretary for Health, and Dr. Samuel Posner, Preventing Chronic Disease Editor in Chief, about the definition and burden of multiple chronic conditions in the United States.  Created: 5/20/2013 by Preventing Chronic Disease (PCD), National Center for Chronic Disease Prevention and Health Promotion (NCCDPHP).   Date Released: 5/20/2013.

  14. Social climber attachment in forming networks produces a phase transition in a measure of connectivity

    Science.gov (United States)

    Taylor, Dane; Larremore, Daniel B.

    2012-09-01

    The formation and fragmentation of networks are typically studied using percolation theory, but most previous research has been restricted to studying a phase transition in cluster size, examining the emergence of a giant component. This approach does not study the effects of evolving network structure on dynamics that occur at the nodes, such as the synchronization of oscillators and the spread of information, epidemics, and neuronal excitations. We introduce and analyze an alternative link-formation rule, called social climber (SC) attachment, that may be combined with arbitrary percolation models to produce a phase transition using the largest eigenvalue of the network adjacency matrix as the order parameter. This eigenvalue is significant in the analyses of many network-coupled dynamical systems in which it measures the quality of global coupling and is hence a natural measure of connectivity. We highlight the important self-organized properties of SC attachment and discuss implications for controlling dynamics on networks.

  15. A game theory-based trust measurement model for social networks.

    Science.gov (United States)

    Wang, Yingjie; Cai, Zhipeng; Yin, Guisheng; Gao, Yang; Tong, Xiangrong; Han, Qilong

    2016-01-01

    In social networks, trust is a complex social network. Participants in online social networks want to share information and experiences with as many reliable users as possible. However, the modeling of trust is complicated and application dependent. Modeling trust needs to consider interaction history, recommendation, user behaviors and so on. Therefore, modeling trust is an important focus for online social networks. We propose a game theory-based trust measurement model for social networks. The trust degree is calculated from three aspects, service reliability, feedback effectiveness, recommendation credibility, to get more accurate result. In addition, to alleviate the free-riding problem, we propose a game theory-based punishment mechanism for specific trust and global trust, respectively. We prove that the proposed trust measurement model is effective. The free-riding problem can be resolved effectively through adding the proposed punishment mechanism.

  16. The impact of measurement errors in the identification of regulatory networks

    Directory of Open Access Journals (Sweden)

    Sato João R

    2009-12-01

    Full Text Available Abstract Background There are several studies in the literature depicting measurement error in gene expression data and also, several others about regulatory network models. However, only a little fraction describes a combination of measurement error in mathematical regulatory networks and shows how to identify these networks under different rates of noise. Results This article investigates the effects of measurement error on the estimation of the parameters in regulatory networks. Simulation studies indicate that, in both time series (dependent and non-time series (independent data, the measurement error strongly affects the estimated parameters of the regulatory network models, biasing them as predicted by the theory. Moreover, when testing the parameters of the regulatory network models, p-values computed by ignoring the measurement error are not reliable, since the rate of false positives are not controlled under the null hypothesis. In order to overcome these problems, we present an improved version of the Ordinary Least Square estimator in independent (regression models and dependent (autoregressive models data when the variables are subject to noises. Moreover, measurement error estimation procedures for microarrays are also described. Simulation results also show that both corrected methods perform better than the standard ones (i.e., ignoring measurement error. The proposed methodologies are illustrated using microarray data from lung cancer patients and mouse liver time series data. Conclusions Measurement error dangerously affects the identification of regulatory network models, thus, they must be reduced or taken into account in order to avoid erroneous conclusions. This could be one of the reasons for high biological false positive rates identified in actual regulatory network models.

  17. Reward networks in the brain as captured by connectivity measures

    Directory of Open Access Journals (Sweden)

    Estela Camara

    2009-12-01

    Full Text Available An assortment of human behaviors is thought to be driven by rewards including reinforcement learning, novelty processing, learning, decision making, economic choice, incentive motivation, and addiction. In each case the ventral tegmental area / ventral striatum (Nucleus accumbens system (VTA-VS has been implicated as a key structure by functional imaging studies, mostly on the basis of standard, univariate analyses. Here we propose that standard fMRI analysis needs to be complemented by methods that take into account the differential connectivity of the VTA-VS system in the different behavioral contexts in order to describe reward based processes more appropriately. We first consider the wider network for reward processing as it emerged from animal experimentation. Subsequently, an example for a method to assess functional connectivity is given. Finally, we illustrate the usefulness of such analyses by examples regarding reward valuation, reward expectation and the role of reward in addiction.

  18. Know Thyself: Metacognitive Networks and Measures of Consciousness

    Science.gov (United States)

    Pasquali, Antoine; Timmermans, Bert; Cleeremans, Axel

    2010-01-01

    Subjective measures of awareness rest on the assumption that conscious knowledge is knowledge that participants know they possess. Post-Decision Wagering (PDW), recently proposed as a new measure of awareness, requires participants to place a high or a low wager on their decisions. Whereas advantageous wagering indicates awareness of the knowledge…

  19. A Step towards Developing a Sustainability Performance Measure within Industrial Networks

    Directory of Open Access Journals (Sweden)

    Samaneh Shokravi

    2014-04-01

    Full Text Available Despite the plethora of literature in sustainability and supply chain management in the recent years, a quantitative tool that measures the sustainability performance of an industrial supply network, considering the uncertainties of existing data, is hard to find. This conceptual paper is aimed at establishing a quantitative measure for the sustainability performance of industrial supply networks that considers aleatory and epistemic uncertainties in its environmental performance evaluation. The measure is built upon economic, environmental and social performance evaluation models. These models address a number of shortcomings in the literature, such as incomplete and inaccurate calculation of environmental impacts, as well as the disregard for aleatory and epistemic uncertainties in the input data and, more importantly, the scarce number of quantitative social sustainability measures. Dyadic interactions are chosen for the network, while the network members have a revenue-sharing relationship. This relationship promotes sharing of the required information for the use of the proposed model. This measure provides an approach to quantify the environmental, social and economic sustainability performances of a supply network. Moreover, as this measure is not specifically designed for an industrial sector, it can be employed over an evolving and diverse industrial network.

  20. Using a body sensor network to measure the effect of fatigue on stair climbing performance

    International Nuclear Information System (INIS)

    Bergmann, Jeroen H M; Smith, Ian C H; Mayagoitia, Ruth E

    2012-01-01

    In terms of self-rated health, the most important activities of daily living are those involving mobility. Of these activities stair climbing is regarded as the most strenuous. A loss of stair climbing ability with age is normally associated with a loss of muscle strength and power, while other factors that influence muscle function, such as fatigue, are often not taken into account. So far no research has been published on how long-lasting fatigue affects activities of daily living, despite the fact that it has been repeatedly proven, in laboratory settings, to influence muscle force production over long periods of time. Technological advances in body sensor networks (BSNs) now provide a method to measure performance during complex real-life situations. In this study the use of a BSN was explored to investigate the effects of long-lasting fatigue on stair climbing performance in 20 healthy adults. Stair climbing performance was measured before and after a fatiguing protocol using a BSN. Performance was defined by temporal and spatial parameters. Long-lasting fatigue was successfully induced in all participants using an exercise protocol. The BSN showed that post-exercise fatigue did not influence stair climbing times (p > 0.2) and no meaningful changes in joint angles were found. No effect on overall stair climbing performance was found, despite a clear presence of long-lasting fatigue. This study shows that physiological paradigms can be further explored using BSNs. Ecological validity of lab-based measurements can be increased by combining them with BSNs. (paper)