WorldWideScience

Sample records for network performance characteristics

  1. Performance Evaluation of 14 Neural Network Architectures Used for Predicting Heat Transfer Characteristics of Engine Oils

    Science.gov (United States)

    Al-Ajmi, R. M.; Abou-Ziyan, H. Z.; Mahmoud, M. A.

    2012-01-01

    This paper reports the results of a comprehensive study that aimed at identifying best neural network architecture and parameters to predict subcooled boiling characteristics of engine oils. A total of 57 different neural networks (NNs) that were derived from 14 different NN architectures were evaluated for four different prediction cases. The NNs were trained on experimental datasets performed on five engine oils of different chemical compositions. The performance of each NN was evaluated using a rigorous statistical analysis as well as careful examination of smoothness of predicted boiling curves. One NN, out of the 57 evaluated, correctly predicted the boiling curves for all cases considered either for individual oils or for all oils taken together. It was found that the pattern selection and weight update techniques strongly affect the performance of the NNs. It was also revealed that the use of descriptive statistical analysis such as R2, mean error, standard deviation, and T and slope tests, is a necessary but not sufficient condition for evaluating NN performance. The performance criteria should also include inspection of the smoothness of the predicted curves either visually or by plotting the slopes of these curves.

  2. Artificial neural network based modeling of performance characteristics of deep well pumps with splitter blade

    International Nuclear Information System (INIS)

    Goelcue, Mustafa

    2006-01-01

    Experimental studies were made to investigate the effects of splitter blade length (25%, 35%, 50%, 60% and 80% of the main blade length) on the pump characteristics of deep well pumps for different blade numbers (z=3, 4, 5, 6 and 7). In this study, an artificial neural network (ANN) was used for modeling the performance of deep well pumps with splitter blades. Two hundred and ten experimental results were used to train and test. Forty-two patterns have been randomly selected and used as the test data. The main parameters for the experiments are the blade number (z), non-dimensional splitter blade length (L-bar ), flow rate (Q, l/s), head (H m , m), efficiency (η, %) and power (P e , kW). z, L-bar and Q have been used as the input layer, and H m and η have also been used as the output layer. The best training algorithm and number of neurons were obtained. Training of the network was performed using the Levenberg-Marquardt (LM) algorithm. To determine the effect of the transfer function, different ANN models are trained, and the results of these ANN models are compared. Some statistical methods; fraction of variance (R 2 ) and root mean squared error (RMSE) values, have been used for comparison

  3. A Hierarchy of Network Performance Characteristics for Grid Applications and Services

    Energy Technology Data Exchange (ETDEWEB)

    Lowekamp, B

    2004-07-06

    This document describes a standard set of network characteristics that are useful for Grid applications and services as well as a classification hierarchy for these characteristics. The goal of this work is to identify the various types of network measurements according to the network characteristic they measure and the network entity on which they are taken. This document defines standard terminology to describe those measurements, but it does not attempt to define new standard measurement methodologies or attempt to define the best measurement methodologies to use for grid applications. However, it does attempt to point out the advantages and disadvantages of different measurement methodologies. This document was motivated by the need for the interchange of measurements taken by various systems in the Grid and to develop a common dictionary to facilitate discussions about and specifications for measurement systems. The application of this naming system will facilitate the creation of common schemata for describing network monitoring data in Grid Monitoring and Discovery Services, and thus help to address portability issues between the wide variety of network measurements used between sites of a Grid.

  4. Network Characteristics of Successful Performance in Association Football. A Study on the UEFA Champions League

    Directory of Open Access Journals (Sweden)

    Tiago J. Pina

    2017-07-01

    Full Text Available The synergistic interaction between teammates in association football has properties that can be captured by Social Network Analysis (SNA. The analysis of networks formed by team players passing a ball in a match shows that team success is correlated with high network density and clustering coefficient, as well as with reduced network centralization. However, oversimplification needs to be avoided, as network metrics events associated with success should not be considered equally to those that are not. In the present study, we investigated whether network density, clustering coefficient and centralization can predict successful or unsuccessful team performance. We analyzed 12 games of the Group Stage of UEFA Champions League 2015/2016 Group C by using public records from TV broadcasts. Notational analyses were performed to categorize attacking sequences as successful or unsuccessful, and to collect data on the ball-passing networks. The network metrics were then computed. A hierarchical logistic-regression model was used to predict the successfulness of the offensive plays from network density, clustering coefficient and centralization, after controlling for the effect of total passes on successfulness of offensive plays. Results confirmed the independent effect of network metrics. Density, but not clustering coefficient or centralization, was a significant predictor of the successfulness of offensive plays. We found a negative relation between density and successfulness of offensive plays. However, reduced density was associated with a higher number of offensive plays, albeit mostly unsuccessful. Conversely, high density was associated with a lower number of successful offensive plays (SOPs, but also with overall fewer offensive plays and “ball possession losses” before the attacking team entered the finishing zone. Independent SNA of team performance is important to minimize the limitations of oversimplifying effective team synergies.

  5. Analyzing the impact of relay station characteristics on uplink performance in cellular network

    NARCIS (Netherlands)

    Dimitrova, D.C.; van den Berg, Hans Leo; Heijenk, Geert

    2009-01-01

    Uplink users in cellular networks, such as UMTS/ HSPA, located at the edge of the cell generally suffer from poor channel conditions. Deploying intermediate relay nodes is seen as a promising approach towards extending cell coverage. This paper focuses on the role of packet scheduling in cellular

  6. SME network characteristics vs. product innovativeness: how to achieve high innovation performance

    NARCIS (Netherlands)

    Pullen, A.J.J.; de Weerd-Nederhof, Petronella C.; Groen, Arend J.; Fisscher, O.A.M.

    2012-01-01

    Small- and medium-sized enterprises (SMEs) must on the one hand innovate for company survival with the appropriate degree of product innovativeness, and on the other they need to collaborate and focus on core competences for efficiency matters. This research examines the relation of network

  7. Network survivability performance

    Science.gov (United States)

    1993-11-01

    This technical report has been developed to address the survivability of telecommunications networks including services. It responds to the need for a common understanding of, and assessment techniques for network survivability, availability, integrity, and reliability. It provides a basis for designing and operating telecommunications networks to user expectations for network survivability and a foundation for continuing industry activities in the subject area. This report focuses on the survivability of both public and private networks and covers a wide range of users. Two frameworks are established for quantifying and categorizing service outages, and for classifying network survivability techniques and measures. The performance of the network survivability techniques is considered; however, recommended objectives are not established for network survivability performance.

  8. Artificial neural network analysis based on genetic algorithm to predict the performance characteristics of a cross flow cooling tower

    Science.gov (United States)

    Wu, Jiasheng; Cao, Lin; Zhang, Guoqiang

    2018-02-01

    Cooling tower of air conditioning has been widely used as cooling equipment, and there will be broad application prospect if it can be reversibly used as heat source under heat pump heating operation condition. In view of the complex non-linear relationship of each parameter in the process of heat and mass transfer inside tower, In this paper, the BP neural network model based on genetic algorithm optimization (GABP neural network model) is established for the reverse use of cross flow cooling tower. The model adopts the structure of 6 inputs, 13 hidden nodes and 8 outputs. With this model, the outlet air dry bulb temperature, wet bulb temperature, water temperature, heat, sensible heat ratio and heat absorbing efficiency, Lewis number, a total of 8 the proportion of main performance parameters were predicted. Furthermore, the established network model is used to predict the water temperature and heat absorption of the tower at different inlet temperatures. The mean relative error MRE between BP predicted value and experimental value are 4.47%, 3.63%, 2.38%, 3.71%, 6.35%,3.14%, 13.95% and 6.80% respectively; the mean relative error MRE between GABP predicted value and experimental value are 2.66%, 3.04%, 2.27%, 3.02%, 6.89%, 3.17%, 11.50% and 6.57% respectively. The results show that the prediction results of GABP network model are better than that of BP network model; the simulation results are basically consistent with the actual situation. The GABP network model can well predict the heat and mass transfer performance of the cross flow cooling tower.

  9. Wireless networked music performance

    CERN Document Server

    Gabrielli, Leonardo

    2016-01-01

    This book presents a comprehensive overview of the state of the art in Networked Music Performance (NMP) and a historical survey of computer music networking. It introduces current technical trends in NMP and technical issues yet to be addressed. It also lists wireless communication protocols and compares these to the requirements of NMP. Practical use cases and advancements are also discussed.

  10. High-Performance Networking

    CERN Multimedia

    CERN. Geneva

    2003-01-01

    The series will start with an historical introduction about what people saw as high performance message communication in their time and how that developed to the now to day known "standard computer network communication". It will be followed by a far more technical part that uses the High Performance Computer Network standards of the 90's, with 1 Gbit/sec systems as introduction for an in depth explanation of the three new 10 Gbit/s network and interconnect technology standards that exist already or emerge. If necessary for a good understanding some sidesteps will be included to explain important protocols as well as some necessary details of concerned Wide Area Network (WAN) standards details including some basics of wavelength multiplexing (DWDM). Some remarks will be made concerning the rapid expanding applications of networked storage.

  11. Network performance analysis

    CERN Document Server

    Bonald, Thomas

    2013-01-01

    The book presents some key mathematical tools for the performance analysis of communication networks and computer systems.Communication networks and computer systems have become extremely complex. The statistical resource sharing induced by the random behavior of users and the underlying protocols and algorithms may affect Quality of Service.This book introduces the main results of queuing theory that are useful for analyzing the performance of these systems. These mathematical tools are key to the development of robust dimensioning rules and engineering methods. A number of examples i

  12. Experimental and artificial neural network based prediction of performance and emission characteristics of DI diesel engine using Calophyllum inophyllum methyl ester at different nozzle opening pressure

    Science.gov (United States)

    Vairamuthu, G.; Thangagiri, B.; Sundarapandian, S.

    2018-01-01

    The present work investigates the effect of varying Nozzle Opening Pressures (NOP) from 220 bar to 250 bar on performance, emissions and combustion characteristics of Calophyllum inophyllum Methyl Ester (CIME) in a constant speed, Direct Injection (DI) diesel engine using Artificial Neural Network (ANN) approach. An ANN model has been developed to predict a correlation between specific fuel consumption (SFC), brake thermal efficiency (BTE), exhaust gas temperature (EGT), Unburnt hydrocarbon (UBHC), CO, CO2, NOx and smoke density using load, blend (B0 and B100) and NOP as input data. A standard Back-Propagation Algorithm (BPA) for the engine is used in this model. A Multi Layer Perceptron network (MLP) is used for nonlinear mapping between the input and the output parameters. An ANN model can predict the performance of diesel engine and the exhaust emissions with correlation coefficient (R2) in the range of 0.98-1. Mean Relative Errors (MRE) values are in the range of 0.46-5.8%, while the Mean Square Errors (MSE) are found to be very low. It is evident that the ANN models are reliable tools for the prediction of DI diesel engine performance and emissions. The test results show that the optimum NOP is 250 bar with B100.

  13. Network survivability performance (computer diskette)

    Science.gov (United States)

    1993-11-01

    File characteristics: Data file; 1 file. Physical description: 1 computer diskette; 3 1/2 in.; high density; 2.0MB. System requirements: Mac; Word. This technical report has been developed to address the survivability of telecommunications networks including services. It responds to the need for a common understanding of, and assessment techniques for network survivability, availability, integrity, and reliability. It provides a basis for designing and operating telecommunication networks to user expectations for network survivability.

  14. Evaluate Data Center Network Performance

    DEFF Research Database (Denmark)

    Pilimon, Artur

    through a data center network, which is usually built with layer 2 switches and layer 3 routers. The topology of the data center network is crucial for latency in the data communication to and from the data center and between servers in the data center. Tests can be conducted to measure latency and other...... Engineering, scientists evaluate data center network topologies with an SDN-based (Software-Defined Networking) control framework measuring network performance – primarily latency. This can be used to plan data center scaling by testing how a new topology will function before changes are made. Data center...... performance parameters for different data center network topologies. It is however important that tests can be repeated and reproduced to have comparable information from the tests. There are, of course, many topologies that can be used for data center networks. At DTU Fotonik, Department of Photonics...

  15. Inferring general relations between network characteristics from specific network ensembles.

    Science.gov (United States)

    Cardanobile, Stefano; Pernice, Volker; Deger, Moritz; Rotter, Stefan

    2012-01-01

    Different network models have been suggested for the topology underlying complex interactions in natural systems. These models are aimed at replicating specific statistical features encountered in real-world networks. However, it is rarely considered to which degree the results obtained for one particular network class can be extrapolated to real-world networks. We address this issue by comparing different classical and more recently developed network models with respect to their ability to generate networks with large structural variability. In particular, we consider the statistical constraints which the respective construction scheme imposes on the generated networks. After having identified the most variable networks, we address the issue of which constraints are common to all network classes and are thus suitable candidates for being generic statistical laws of complex networks. In fact, we find that generic, not model-related dependencies between different network characteristics do exist. This makes it possible to infer global features from local ones using regression models trained on networks with high generalization power. Our results confirm and extend previous findings regarding the synchronization properties of neural networks. Our method seems especially relevant for large networks, which are difficult to map completely, like the neural networks in the brain. The structure of such large networks cannot be fully sampled with the present technology. Our approach provides a method to estimate global properties of under-sampled networks in good approximation. Finally, we demonstrate on three different data sets (C. elegans neuronal network, R. prowazekii metabolic network, and a network of synonyms extracted from Roget's Thesaurus) that real-world networks have statistical relations compatible with those obtained using regression models.

  16. Complexity Characteristics of Currency Networks

    Science.gov (United States)

    Gorski, A. Z.; Drozdz, S.; Kwapien, J.; Oswiecimka, P.

    2006-11-01

    A large set of daily FOREX time series is analyzed. The corresponding correlation matrices (CM) are constructed for USD, EUR and PLN used as the base currencies. The triangle rule is interpreted as constraints reducing the number of independent returns. The CM spectrum is computed and compared with the cases of shuffled currencies and a fictitious random currency taken as a base currency. The Minimal Spanning Tree (MST) graphs are calculated and the clustering effects for strong currencies are found. It is shown that for MSTs the node rank has power like, scale free behavior. Finally, the scaling exponents are evaluated and found in the range analogous to those identified recently for various complex networks.

  17. Social Networks and Sales Performance

    Directory of Open Access Journals (Sweden)

    Danny Pimentel Claro

    2011-05-01

    Full Text Available This paper argues that an informal network can itself be a basis for the increase in a sales manager’s performance. Informal networks create a structure that surpasses the formal hierarchical structure defined by the firm. We concentrated on the advice network and considered two different views of network structure that claim to have impact on performance. To explore this claim, we examined whether sales managers develop either a highly cohesive network structure (i.e. Coleman’s view or one containing structural holes (i.e. Burt’s view in order to achieve higher sales. We also investigated the matter of tie strength put forward by Granovetter in his seminal 1973 work. Census data was collected from about 500 personnel from an agricultural input retailer having 23 divisions. Estimates from a sample of 101 sales managers showed the importance of a highly cohesive structure (degree centrality for the three measures of sales manager’s performance. The strong ties have a positive impact on performance, suggesting the importance of building up strong bonds with network contacts. Sales managers’ age, time within the retailer and education also influence performance. These results imply that firms should stimulate contacts among personnel to spread technical and commercial information.

  18. Understanding Team Communication Characteristics using Social Network Analysis

    International Nuclear Information System (INIS)

    Kim, Ar Ryum; Lee, Seung Woo; Seong, Poong Hyun; Park, Jin Kyun

    2011-01-01

    An important aspect of human behavior in nuclear power plants (NPPs) is team interaction since operating NPPs involves the coordination of several team members among and within workplaces. Since operators in main control room (MCR) get a great deal of information through communication to perform a task, communication is one of the important characteristics for team characteristics. Many researchers have been studying how to understand the characteristics of communication. Social network analysis (SNA) which is considered as an objective and easily applicable method has been already applied in many fields to investigate characteristics of team communication. Henttonen (2010) has struggled to perform the research on the impact of social networks in a team and he found some team communication characteristics could be obtained using some properties of SNA. In this paper, SNA is used to understand communication characteristics within operators in NPPs

  19. Wireless network simulation - Your window on future network performance

    NARCIS (Netherlands)

    Fledderus, E.

    2005-01-01

    The paper describes three relevant perspectives on current wireless simulation practices. In order to obtain the key challenges for future network simulations, the characteristics of "beyond 3G" networks are described, including their impact on simulation.

  20. Characteristic imsets for learning Bayesian network structure

    Czech Academy of Sciences Publication Activity Database

    Hemmecke, R.; Lindner, S.; Studený, Milan

    2012-01-01

    Roč. 53, č. 9 (2012), s. 1336-1349 ISSN 0888-613X R&D Projects: GA MŠk(CZ) 1M0572; GA ČR GA201/08/0539 Institutional support: RVO:67985556 Keywords : learning Bayesian network structure * essential graph * standard imset * characteristic imset * LP relaxation of a polytope Subject RIV: BA - General Mathematics Impact factor: 1.729, year: 2012 http://library.utia.cas.cz/separaty/2012/MTR/studeny-0382596.pdf

  1. Developing countries SMEs innovation characteristics and performance

    DEFF Research Database (Denmark)

    Vang, Jan; Rezaei, Shahamak; Baklanov, Nikita

    An econometric study analysing developing countries’ SMEs innovation characteristics and their correlation with performance.......An econometric study analysing developing countries’ SMEs innovation characteristics and their correlation with performance....

  2. Characteristics of the TRISTAN control computer network

    International Nuclear Information System (INIS)

    Kurokawa, Shinichi; Akiyama, Atsuyoshi; Katoh, Tadahiko; Kikutani, Eiji; Koiso, Haruyo; Oide, Katsunobu; Shinomoto, Manabu; Kurihara, Michio; Abe, Kenichi

    1986-01-01

    Twenty-four minicomputers forming an N-to-N token-ring network control the TRISTAN accelerator complex. The computers are linked by optical fiber cables with 10 Mbps transmission speed. The software system is based on NODAL, a multicomputer interpretive language developed at the CERN SPS. The high-level services offered to the users of the network are remote execution by the EXEC, EXEC-P and IMEX commands of NODAL and uniform file access throughout the system. The network software was designed to achieve the fast response of the EXEC command. The performance of the network is also reported. Tasks that overload the minicomputers are processed on the KEK central computers. One minicomputer in the network serves as a gateway to KEKNET, which connects the minicomputer network and the central computers. The communication with the central computers is managed within the framework of the KEK NODAL system. NODAL programs communicate with the central computers calling NODAL functions; functions for exchanging data between a data set on the central computers and a NODAL variable, submitting a batch job to the central computers, checking the status of the submitted job, etc. are prepared. (orig.)

  3. Network Performance Improvement under Epidemic Failures in Optical Transport Networks

    DEFF Research Database (Denmark)

    Fagertun, Anna Manolova; Ruepp, Sarah Renée

    2013-01-01

    In this paper we investigate epidemic failure spreading in large- scale GMPLS-controlled transport networks. By evaluating the effect of the epidemic failure spreading on the network, we design several strategies for cost-effective network performance improvement via differentiated repair times....... First we identify the most vulnerable and the most strategic nodes in the network. Then, via extensive simulations we show that strategic placement of resources for improved failure recovery has better performance than randomly assigning lower repair times among the network nodes. Our OPNET simulation...... model can be used during the network planning process for facilitating cost- effective network survivability design....

  4. Artificial neural network simulation of battery performance

    Energy Technology Data Exchange (ETDEWEB)

    O`Gorman, C.C.; Ingersoll, D.; Jungst, R.G.; Paez, T.L.

    1998-12-31

    Although they appear deceptively simple, batteries embody a complex set of interacting physical and chemical processes. While the discrete engineering characteristics of a battery such as the physical dimensions of the individual components, are relatively straightforward to define explicitly, their myriad chemical and physical processes, including interactions, are much more difficult to accurately represent. Within this category are the diffusive and solubility characteristics of individual species, reaction kinetics and mechanisms of primary chemical species as well as intermediates, and growth and morphology characteristics of reaction products as influenced by environmental and operational use profiles. For this reason, development of analytical models that can consistently predict the performance of a battery has only been partially successful, even though significant resources have been applied to this problem. As an alternative approach, the authors have begun development of a non-phenomenological model for battery systems based on artificial neural networks. Both recurrent and non-recurrent forms of these networks have been successfully used to develop accurate representations of battery behavior. The connectionist normalized linear spline (CMLS) network has been implemented with a self-organizing layer to model a battery system with the generalized radial basis function net. Concurrently, efforts are under way to use the feedforward back propagation network to map the {open_quotes}state{close_quotes} of a battery system. Because of the complexity of battery systems, accurate representation of the input and output parameters has proven to be very important. This paper describes these initial feasibility studies as well as the current models and makes comparisons between predicted and actual performance.

  5. Network Congestion and Performance Management

    OpenAIRE

    Shewmaker, Andrew Glenn

    2016-01-01

    We increasingly depend on well-behaved networks in the course of every-day activities for business, community, government, science, and recreation. And with more people demanding a greater variety of services comes sharp disagreement about which needs are most important. Unfortunately, today’s technology is inadequate to guarantee the performance of dynamic and diverse workloads in such a way that we are prevented from hurting each other’s goals.No one likes waiting in traffic, whether on a r...

  6. Organizing NPD networks for high innovation performance: the case of Dutch medical devices SMEs

    NARCIS (Netherlands)

    Pullen, A.J.J.; Groen, Arend J.; de Weerd-Nederhof, Petronella C.; Fisscher, O.A.M.

    2010-01-01

    This research examines which combination of network characteristics (the network configuration) leads to high innovation performance for small and medium sized companies (SMEs). Even though research has paid significant attention to the relation between the external network and the innovation

  7. performance performance analysis of gsm networks in minna

    African Journals Online (AJOL)

    eobe

    in terms of key performance indicators (KPI) based on statistics performance indicators ... in this study. Keywords: GSM Network, Drive Test, KPI and Radio Frequency Network Optimization. 1. .... message (SMS) traffic or in scenarios where so.

  8. The Homogeneity Research of Urban Rail Transit Network Performance

    Directory of Open Access Journals (Sweden)

    Wang Fu-jian

    2016-01-01

    Full Text Available Urban Rail Transit is an important part of the public transit, it is necessary to carry out the corresponding network function analysis. Previous studies mainly about network performance analysis of a single city rail transit, lacking of horizontal comparison between the multi-city, it is difficult to find inner unity of different Urban Rail Transit network functions. Taking into account the Urban Rail Transit network is a typical complex networks, so this paper proposes the application of complex network theory to research the homogeneity of Urban Rail Transit network performance. This paper selects rail networks of Beijing, Shanghai, Guangzhou as calculation case, gave them a complex network mapping through the L, P Space method and had a static topological analysis using complex network theory, Network characteristics in three cities were calculated and analyzed form node degree distribution and node connection preference. Finally, this paper studied the network efficiency changes of Urban Rail Transit system under different attack mode. The results showed that, although rail transport network size, model construction and construction planning of the three cities are different, but their network performance in many aspects showed high homogeneity.

  9. Performance characteristics of the Mayo/IBM PACS

    Science.gov (United States)

    Persons, Kenneth R.; Gehring, Dale G.; Pavicic, Mark J.; Ding, Yingjai

    1991-07-01

    The Mayo Clinic and IBM (at Rochester, Minnesota) have jointly developed a picture archiving system for use with Mayo's MRI and Neuro CT imaging modalities. The communications backbone of the PACS is a portion of the Mayo institutional network: a series of 4-Mbps token rings interconnected by bridges and fiber optic extensions. The performance characteristics of this system are important to understand because they affect the response time a PACS user can expect, and the response time for non-PACS users competing for resources on the institutional network. The performance characteristics of each component and the average load levels of the network were measured for various load distributions. These data were used to quantify the response characteristics of the existing system and to tune a model developed by North Dakota State University Department of Computer Science for predicting response times of more complex topologies.

  10. Diagnosing Anomalous Network Performance with Confidence

    Energy Technology Data Exchange (ETDEWEB)

    Settlemyer, Bradley W [ORNL; Hodson, Stephen W [ORNL; Kuehn, Jeffery A [ORNL; Poole, Stephen W [ORNL

    2011-04-01

    Variability in network performance is a major obstacle in effectively analyzing the throughput of modern high performance computer systems. High performance interconnec- tion networks offer excellent best-case network latencies; how- ever, highly parallel applications running on parallel machines typically require consistently high levels of performance to adequately leverage the massive amounts of available computing power. Performance analysts have usually quantified network performance using traditional summary statistics that assume the observational data is sampled from a normal distribution. In our examinations of network performance, we have found this method of analysis often provides too little data to under- stand anomalous network performance. Our tool, Confidence, instead uses an empirically derived probability distribution to characterize network performance. In this paper we describe several instances where the Confidence toolkit allowed us to understand and diagnose network performance anomalies that we could not adequately explore with the simple summary statis- tics provided by traditional measurement tools. In particular, we examine a multi-modal performance scenario encountered with an Infiniband interconnection network and we explore the performance repeatability on the custom Cray SeaStar2 interconnection network after a set of software and driver updates.

  11. Network characteristics and open innovation in SMEs

    DEFF Research Database (Denmark)

    Pedersen, Maja; Søndergaard, Helle Alsted; Esbjerg, Lars

    The open innovation literature has primarily been concentrating on open innovation (OI) in large companies. Hence it is very unclear whether these findings can be generalized to small and medium-sized enterprises (SMEs). This paper begins filling in this knowledge gap. In doing so, we focus...... explicitly on understanding network characteristics and the unfolding of OI in SMEs. Case studies were used and empirical data was mainly generated through semi-structured interviews. Cases selected for study were companies in the Danish food industry with less than 499 employees. In this paper we report our...... findings for four cases. Our study shows that companies with a relatively open innovation process have both strong and weak ties with external partners. Companies with a relatively more closed innovation process have on the other hand only few weak ties and no strong ties with external partners....

  12. Noise characteristics of single-walled carbon nanotube network transistors

    International Nuclear Information System (INIS)

    Kim, Un Jeong; Kim, Kang Hyun; Kim, Kyu Tae; Min, Yo-Sep; Park, Wanjun

    2008-01-01

    The noise characteristics of randomly networked single-walled carbon nanotubes grown directly by plasma enhanced chemical vapor deposition (PECVD) are studied with field effect transistors (FETs). Due to the geometrical complexity of nanotube networks in the channel area and the large number of tube-tube/tube-metal junctions, the inverse frequency, 1/f, dependence of the noise shows a similar level to that of a single single-walled carbon nanotube transistor. Detailed analysis is performed with the parameters of number of mobile carriers and mobility in the different environment. This shows that the change in the number of mobile carriers resulting in the mobility change due to adsorption and desorption of gas molecules (mostly oxygen molecules) to the tube surface is a key factor in the 1/f noise level for carbon nanotube network transistors

  13. Analysis of Network Parameters Influencing Performance of Hybrid Multimedia Networks

    Directory of Open Access Journals (Sweden)

    Dominik Kovac

    2013-10-01

    Full Text Available Multimedia networks is an emerging subject that currently attracts the attention of research and industrial communities. This environment provides new entertainment services and business opportunities merged with all well-known network services like VoIP calls or file transfers. Such a heterogeneous system has to be able satisfy all network and end-user requirements which are increasing constantly. Therefore the simulation tools enabling deep analysis in order to find the key performance indicators and factors which influence the overall quality for specific network service the most are highly needed. This paper provides a study on the network parameters like communication technology, routing protocol, QoS mechanism, etc. and their effect on the performance of hybrid multimedia network. The analysis was performed in OPNET Modeler environment and the most interesting results are discussed at the end of this paper

  14. A method of network topology optimization design considering application process characteristic

    Science.gov (United States)

    Wang, Chunlin; Huang, Ning; Bai, Yanan; Zhang, Shuo

    2018-03-01

    Communication networks are designed to meet the usage requirements of users for various network applications. The current studies of network topology optimization design mainly considered network traffic, which is the result of network application operation, but not a design element of communication networks. A network application is a procedure of the usage of services by users with some demanded performance requirements, and has obvious process characteristic. In this paper, we first propose a method to optimize the design of communication network topology considering the application process characteristic. Taking the minimum network delay as objective, and the cost of network design and network connective reliability as constraints, an optimization model of network topology design is formulated, and the optimal solution of network topology design is searched by Genetic Algorithm (GA). Furthermore, we investigate the influence of network topology parameter on network delay under the background of multiple process-oriented applications, which can guide the generation of initial population and then improve the efficiency of GA. Numerical simulations show the effectiveness and validity of our proposed method. Network topology optimization design considering applications can improve the reliability of applications, and provide guidance for network builders in the early stage of network design, which is of great significance in engineering practices.

  15. Performance modeling of network data services

    Energy Technology Data Exchange (ETDEWEB)

    Haynes, R.A.; Pierson, L.G.

    1997-01-01

    Networks at major computational organizations are becoming increasingly complex. The introduction of large massively parallel computers and supercomputers with gigabyte memories are requiring greater and greater bandwidth for network data transfers to widely dispersed clients. For networks to provide adequate data transfer services to high performance computers and remote users connected to them, the networking components must be optimized from a combination of internal and external performance criteria. This paper describes research done at Sandia National Laboratories to model network data services and to visualize the flow of data from source to sink when using the data services.

  16. Propagation Characteristics of International Space Station Wireless Local Area Network

    Science.gov (United States)

    Sham, Catherine C.; Hwn, Shian U.; Loh, Yin-Chung

    2005-01-01

    This paper describes the application of the Uniform Geometrical Theory of Diffraction (UTD) for Space Station Wireless Local Area Networks (WLANs) indoor propagation characteristics analysis. The verification results indicate good correlation between UTD computed and measured signal strength. It is observed that the propagation characteristics are quite different in the Space Station modules as compared with those in the typical indoor WLANs environment, such as an office building. The existing indoor propagation models are not readily applicable to the Space Station module environment. The Space Station modules can be regarded as oversized imperfect waveguides. Two distinct propagation regions separated by a breakpoint exist. The propagation exhibits the guided wave characteristics. The propagation loss in the Space Station, thus, is much smaller than that in the typical office building. The path loss model developed in this paper is applicable for Space Station WLAN RF coverage and link performance analysis.

  17. RF Characteristics of Mica-Z Wireless Sensor Network Motes

    National Research Council Canada - National Science Library

    Koh, Swee J

    2006-01-01

    ... network characteristics. Link-break and re-association distances with their corresponding RF power measurements were recorded to determine the Mica-Z s range characteristics under these different operating environments...

  18. An investigation and comparison on network performance analysis

    OpenAIRE

    Lanxiaopu, Mi

    2012-01-01

    This thesis is generally about network performance analysis. It contains two parts. The theory part summarizes what network performance is and inducts the methods of doing network performance analysis. To answer what network performance is, a study into what network services are is done. And based on the background research, there are two important network performance metrics: Network delay and Throughput should be included in network performance analysis. Among the methods of network a...

  19. Social Networking and Academic Performance: A Review

    Science.gov (United States)

    Doleck, Tenzin; Lajoie, Susanne

    2018-01-01

    The ubiquitous use of social networking sites by students and the potential impacts of such use on academic performance are of both theoretical and practical importance. Hence, this paper addresses the question: how does the use of social networking sites influence academic performance? The present review synthesizes the empirical findings of the…

  20. Optical Networks Solutions planning - performances - management

    DEFF Research Database (Denmark)

    Fenger, Christian

    2002-01-01

    It has been a decisive goal in the compilation of this thesis to make us capable of realizing the future national and regional telecommunication networks in an efficient and resource optimal way. By future telecommunication network is assumed an all optical network where the information in transit...... are kept optical and not converted into the optical domain. The focus is on the scientific results achieved throughout the Ph.D. period. Five subjects – all increasing the understanding of optical networks – are studied. Static wavelength routed optical networks are studied. Management on terms...... of lightpath allocation and design is considered. By using statistical models (simultaneous analysis of many networks) the correspondence between parameters determining the network topology and the performance of the optical network is found. These dependencies are important knowledge in the process...

  1. Relations between mental health team characteristics and work role performance.

    Science.gov (United States)

    Fleury, Marie-Josée; Grenier, Guy; Bamvita, Jean-Marie; Farand, Lambert

    2017-01-01

    Effective mental health care requires a high performing, interprofessional team. Among 79 mental health teams in Quebec (Canada), this exploratory study aims to 1) determine the association between work role performance and a wide range of variables related to team effectiveness according to the literature, and to 2) using structural equation modelling, assess the covariance between each of these variables as well as the correlation with other exogenous variables. Work role performance was measured with an adapted version of a work role questionnaire. Various independent variables including team manager characteristics, user characteristics, team profiles, clinical activities, organizational culture, network integration strategies and frequency/satisfaction of interactions with other teams or services were analyzed under the structural equation model. The later provided a good fit with the data. Frequent use of standardized procedures and evaluation tools (e.g. screening and assessment tools for mental health disorders) and team manager seniority exerted the most direct effect on work role performance. While network integration strategies had little effect on work role performance, there was a high covariance between this variable and those directly affecting work role performance among mental health teams. The results suggest that the mental healthcare system should apply standardized procedures and evaluation tools and, to a lesser extent, clinical approaches to improve work role performance in mental health teams. Overall, a more systematic implementation of network integration strategies may contribute to improved work role performance in mental health care.

  2. WiMAX network performance monitoring & optimization

    DEFF Research Database (Denmark)

    Zhang, Qi; Dam, H

    2008-01-01

    frequency reuse, capacity planning, proper network dimensioning, multi-class data services and so on. Furthermore, as a small operator we also want to reduce the demand for sophisticated technicians and man labour hours. To meet these critical demands, we design a generic integrated network performance......In this paper we present our WiMAX (worldwide interoperability for microwave access) network performance monitoring and optimization solution. As a new and small WiMAX network operator, there are many demanding issues that we have to deal with, such as limited available frequency resource, tight...... this integrated network performance monitoring and optimization system in our WiMAX networks. This integrated monitoring and optimization system has such good flexibility and scalability that individual function component can be used by other operators with special needs and more advanced function components can...

  3. Board characteristics, governance objectives, and hospital performance

    DEFF Research Database (Denmark)

    Thiel, Andrea; Winter, Vera; Büchner, Vera Antonia

    2018-01-01

    membership relates to board characteristics and financial performance. METHODOLOGY: Using factor analysis, we identify latent classes of governance objectives and use hierarchical cluster analysis to detect distinct clusters with varying emphasis on the classes. We then use multinomial regression to explore...... the associations between cluster membership and board characteristics (size, gender diversity, and occupational diversity) and examine the associations between clusters and financial performance using OLS regression. RESULTS: Classes of objectives reflecting three governance theories-agency theory, stewardship...... and hospital financial performance, with two of three groups performing significantly better than the reference group. CONCLUSION: High performance in hospitals can be the result of governance logics, which, compared to simple board characteristics, are associated with better financial outcomes. PRACTICE...

  4. Evolution Characteristics of the Network Core in the Facebook

    OpenAIRE

    Liu, Jian-Guo; Ren, Zhuo-Ming; Guo, Qiang; Chen, Duan-Bing

    2014-01-01

    Statistical properties of the static networks have been extensively studied. However, online social networks are evolving dynamically, understanding the evolving characteristics of the core is one of major concerns in online social networks. In this paper, we empirically investigate the evolving characteristics of the Facebook core. Firstly, we separate the Facebook-link(FL) and Facebook-wall(FW) datasets into 28 snapshots in terms of timestamps. By employing the k-core decomposition method t...

  5. Cost and Demand Characteristics of Telecom Networks

    DEFF Research Database (Denmark)

    Falch, Morten

    1997-01-01

    The Chapter presents the general characteristics of the cost and demand profiles for telecommunication services and identifies the barriers towards a free competitive market for telecommunication services related to these characteristics.......The Chapter presents the general characteristics of the cost and demand profiles for telecommunication services and identifies the barriers towards a free competitive market for telecommunication services related to these characteristics....

  6. Growth performance, carcass and hematological characteristics of ...

    African Journals Online (AJOL)

    Growth performance, carcass and hematological characteristics of rabbits fed graded levels of tiger nuts ( Cyperus esculentus ) ... (p>0.05) difference between treatments. Results demonstrated that (Cyperus esculentus) could be used up to 5% in rabbit's diets without adverse effect on the animals' performance and health.

  7. Artificial Astrocytes Improve Neural Network Performance

    Science.gov (United States)

    Porto-Pazos, Ana B.; Veiguela, Noha; Mesejo, Pablo; Navarrete, Marta; Alvarellos, Alberto; Ibáñez, Oscar; Pazos, Alejandro; Araque, Alfonso

    2011-01-01

    Compelling evidence indicates the existence of bidirectional communication between astrocytes and neurons. Astrocytes, a type of glial cells classically considered to be passive supportive cells, have been recently demonstrated to be actively involved in the processing and regulation of synaptic information, suggesting that brain function arises from the activity of neuron-glia networks. However, the actual impact of astrocytes in neural network function is largely unknown and its application in artificial intelligence remains untested. We have investigated the consequences of including artificial astrocytes, which present the biologically defined properties involved in astrocyte-neuron communication, on artificial neural network performance. Using connectionist systems and evolutionary algorithms, we have compared the performance of artificial neural networks (NN) and artificial neuron-glia networks (NGN) to solve classification problems. We show that the degree of success of NGN is superior to NN. Analysis of performances of NN with different number of neurons or different architectures indicate that the effects of NGN cannot be accounted for an increased number of network elements, but rather they are specifically due to astrocytes. Furthermore, the relative efficacy of NGN vs. NN increases as the complexity of the network increases. These results indicate that artificial astrocytes improve neural network performance, and established the concept of Artificial Neuron-Glia Networks, which represents a novel concept in Artificial Intelligence with implications in computational science as well as in the understanding of brain function. PMID:21526157

  8. Artificial astrocytes improve neural network performance.

    Directory of Open Access Journals (Sweden)

    Ana B Porto-Pazos

    Full Text Available Compelling evidence indicates the existence of bidirectional communication between astrocytes and neurons. Astrocytes, a type of glial cells classically considered to be passive supportive cells, have been recently demonstrated to be actively involved in the processing and regulation of synaptic information, suggesting that brain function arises from the activity of neuron-glia networks. However, the actual impact of astrocytes in neural network function is largely unknown and its application in artificial intelligence remains untested. We have investigated the consequences of including artificial astrocytes, which present the biologically defined properties involved in astrocyte-neuron communication, on artificial neural network performance. Using connectionist systems and evolutionary algorithms, we have compared the performance of artificial neural networks (NN and artificial neuron-glia networks (NGN to solve classification problems. We show that the degree of success of NGN is superior to NN. Analysis of performances of NN with different number of neurons or different architectures indicate that the effects of NGN cannot be accounted for an increased number of network elements, but rather they are specifically due to astrocytes. Furthermore, the relative efficacy of NGN vs. NN increases as the complexity of the network increases. These results indicate that artificial astrocytes improve neural network performance, and established the concept of Artificial Neuron-Glia Networks, which represents a novel concept in Artificial Intelligence with implications in computational science as well as in the understanding of brain function.

  9. Artificial astrocytes improve neural network performance.

    Science.gov (United States)

    Porto-Pazos, Ana B; Veiguela, Noha; Mesejo, Pablo; Navarrete, Marta; Alvarellos, Alberto; Ibáñez, Oscar; Pazos, Alejandro; Araque, Alfonso

    2011-04-19

    Compelling evidence indicates the existence of bidirectional communication between astrocytes and neurons. Astrocytes, a type of glial cells classically considered to be passive supportive cells, have been recently demonstrated to be actively involved in the processing and regulation of synaptic information, suggesting that brain function arises from the activity of neuron-glia networks. However, the actual impact of astrocytes in neural network function is largely unknown and its application in artificial intelligence remains untested. We have investigated the consequences of including artificial astrocytes, which present the biologically defined properties involved in astrocyte-neuron communication, on artificial neural network performance. Using connectionist systems and evolutionary algorithms, we have compared the performance of artificial neural networks (NN) and artificial neuron-glia networks (NGN) to solve classification problems. We show that the degree of success of NGN is superior to NN. Analysis of performances of NN with different number of neurons or different architectures indicate that the effects of NGN cannot be accounted for an increased number of network elements, but rather they are specifically due to astrocytes. Furthermore, the relative efficacy of NGN vs. NN increases as the complexity of the network increases. These results indicate that artificial astrocytes improve neural network performance, and established the concept of Artificial Neuron-Glia Networks, which represents a novel concept in Artificial Intelligence with implications in computational science as well as in the understanding of brain function.

  10. Social network characteristics associated with health promoting behaviors among Latinos.

    Science.gov (United States)

    Marquez, Becky; Elder, John P; Arredondo, Elva M; Madanat, Hala; Ji, Ming; Ayala, Guadalupe X

    2014-06-01

    This study examined the relationship between social network characteristics and health promoting behaviors (having a routine medical check-up, consuming no alcohol, consuming no fast food, and meeting recommendations for leisure-time physical activity and sleep duration) among Latinos to identify potential targets for behavioral interventions. Personal network characteristics and health behavior data were collected from a community sample of 393 adult Latinos (73% women) in San Diego County, California. Network characteristics consisted of size and composition. Network size was calculated by the number of alters listed on a name generator questionnaire eliciting people with whom respondents discussed personal issues. Network composition variables were the proportion of Latinos, Spanish-speakers, females, family, and friends listed in the name generator. Additional network composition variables included marital status and the number of adults or children in the household. Network members were predominately Latinos (95%), Spanish-speakers (80%), females (64%), and family (55%). In multivariate logistic regression analyses, gender moderated the relationship between network composition, but not size, and a health behavior. Married women were more likely to have had a routine medical check-up than married men. For both men and women, having a larger network was associated with meeting the recommendation for leisure-time physical activity. Few social network characteristics were significantly associated with health promoting behaviors, suggesting a need to examine other aspects of social relationships that may influence health behaviors. PsycINFO Database Record (c) 2014 APA, all rights reserved.

  11. High Performance Networks for High Impact Science

    Energy Technology Data Exchange (ETDEWEB)

    Scott, Mary A.; Bair, Raymond A.

    2003-02-13

    This workshop was the first major activity in developing a strategic plan for high-performance networking in the Office of Science. Held August 13 through 15, 2002, it brought together a selection of end users, especially representing the emerging, high-visibility initiatives, and network visionaries to identify opportunities and begin defining the path forward.

  12. Estimation of Anonymous Email Network Characteristics through Statistical Disclosure Attacks

    Directory of Open Access Journals (Sweden)

    Javier Portela

    2016-11-01

    Full Text Available Social network analysis aims to obtain relational data from social systems to identify leaders, roles, and communities in order to model profiles or predict a specific behavior in users’ network. Preserving anonymity in social networks is a subject of major concern. Anonymity can be compromised by disclosing senders’ or receivers’ identity, message content, or sender-receiver relationships. Under strongly incomplete information, a statistical disclosure attack is used to estimate the network and node characteristics such as centrality and clustering measures, degree distribution, and small-world-ness. A database of email networks in 29 university faculties is used to study the method. A research on the small-world-ness and Power law characteristics of these email networks is also developed, helping to understand the behavior of small email networks.

  13. Estimation of Anonymous Email Network Characteristics through Statistical Disclosure Attacks

    Science.gov (United States)

    Portela, Javier; García Villalba, Luis Javier; Silva Trujillo, Alejandra Guadalupe; Sandoval Orozco, Ana Lucila; Kim, Tai-Hoon

    2016-01-01

    Social network analysis aims to obtain relational data from social systems to identify leaders, roles, and communities in order to model profiles or predict a specific behavior in users’ network. Preserving anonymity in social networks is a subject of major concern. Anonymity can be compromised by disclosing senders’ or receivers’ identity, message content, or sender-receiver relationships. Under strongly incomplete information, a statistical disclosure attack is used to estimate the network and node characteristics such as centrality and clustering measures, degree distribution, and small-world-ness. A database of email networks in 29 university faculties is used to study the method. A research on the small-world-ness and Power law characteristics of these email networks is also developed, helping to understand the behavior of small email networks. PMID:27809275

  14. Enhancing neural-network performance via assortativity

    International Nuclear Information System (INIS)

    Franciscis, Sebastiano de; Johnson, Samuel; Torres, Joaquin J.

    2011-01-01

    The performance of attractor neural networks has been shown to depend crucially on the heterogeneity of the underlying topology. We take this analysis a step further by examining the effect of degree-degree correlations - assortativity - on neural-network behavior. We make use of a method recently put forward for studying correlated networks and dynamics thereon, both analytically and computationally, which is independent of how the topology may have evolved. We show how the robustness to noise is greatly enhanced in assortative (positively correlated) neural networks, especially if it is the hub neurons that store the information.

  15. Competitive Learning Neural Network Ensemble Weighted by Predicted Performance

    Science.gov (United States)

    Ye, Qiang

    2010-01-01

    Ensemble approaches have been shown to enhance classification by combining the outputs from a set of voting classifiers. Diversity in error patterns among base classifiers promotes ensemble performance. Multi-task learning is an important characteristic for Neural Network classifiers. Introducing a secondary output unit that receives different…

  16. Performance analysis of multi-hop wireless packet networks

    Directory of Open Access Journals (Sweden)

    Lim J.-T.

    1997-01-01

    Full Text Available In this paper, a unified analytical framework for performance analysis of multi-hop wireless packet networks is developed. The effect of coupling between the hops on the degradation of the delay-throughput characteristics and the probability of blocking is investigated. The issue of hop decoupling is addressed.

  17. Dismissing Attachment Characteristics Dynamically Modulate Brain Networks Subserving Social Aversion.

    Science.gov (United States)

    Krause, Anna Linda; Borchardt, Viola; Li, Meng; van Tol, Marie-José; Demenescu, Liliana Ramona; Strauss, Bernhard; Kirchmann, Helmut; Buchheim, Anna; Metzger, Coraline D; Nolte, Tobias; Walter, Martin

    2016-01-01

    Attachment patterns influence actions, thoughts and feeling through a person's "inner working model". Speech charged with attachment-dependent content was proposed to modulate the activation of cognitive-emotional schemata in listeners. We performed a 7 Tesla rest-task-rest functional magnetic resonance imaging (fMRI)-experiment, presenting auditory narratives prototypical of dismissing attachment representations to investigate their effect on 23 healthy males. We then examined effects of participants' attachment style and childhood trauma on brain state changes using seed-based functional connectivity (FC) analyses, and finally tested whether subjective differences in responsivity to narratives could be predicted by baseline network states. In comparison to a baseline state, we observed increased FC in a previously described "social aversion network" including dorsal anterior cingulated cortex (dACC) and left anterior middle temporal gyrus (aMTG) specifically after exposure to insecure-dismissing attachment narratives. Increased dACC-seeded FC within the social aversion network was positively related to the participants' avoidant attachment style and presence of a history of childhood trauma. Anxious attachment style on the other hand was positively correlated with FC between the dACC and a region outside of the "social aversion network", namely the dorsolateral prefrontal cortex, which suggests decreased network segregation as a function of anxious attachment. Finally, the extent of subjective experience of friendliness towards the dismissing narrative was predicted by low baseline FC-values between hippocampus and inferior parietal lobule (IPL). Taken together, our study demonstrates an activation of networks related to social aversion in terms of increased connectivity after listening to insecure-dismissing attachment narratives. A causal interrelation of brain state changes and subsequent changes in social reactivity was further supported by our observation of

  18. Structural integration and performance of inter-sectoral public health-related policy networks: An analysis across policy phases

    NARCIS (Netherlands)

    Peters, D. T. J. M.; Raab, J.; Grêaux, K. M.; Stronks, K.; Harting, J.

    2017-01-01

    Background: Inter-sectoral policy networks may be effective in addressing environmental determinants of health with interventions. However, contradictory results are reported on relations between structural network characteristics (i.e., composition and integration) and network performance, such as

  19. Structural integration and performance of inter-sectoral public health-related policy networks : An analysis across policy phases

    NARCIS (Netherlands)

    Peters, Dorothee; Raab, J.; Grêaux, Kimberley M.; Stronks, Karien; Harting, Janneke

    2017-01-01

    Background: Inter-sectoral policy networks may be effective in addressing environmental determinants of health with interventions. However, contradictory results are reported on relations between structure and network characteristics (i.e., composition and integration) and network performance, such

  20. Network performance for graphical control systems

    International Nuclear Information System (INIS)

    Clout, P.; Geib, M.; Westervelt, R.

    1992-01-01

    Vsystem is a toolbox for building graphically-based control systems. The real-tiem database component, Vaccess, includes all the networking support necessary to build multi-computer control systems. Vaccess has two modes of database access, synchronous and asynchronous. Vdraw is another component of Vsystem that allows developers and users to develop control screens and windows by drawing rather than programming. Based on X-windows, Vsystem provides the possibility of running Vdraw either on the workstation with the graphics or on the computer with the database. We have made some measurements on the cpu loading, elapsed time and the network loading to give some guidance in system configuration performance. It will be seen that asynchronous network access gives large performance increases and that the network database change notification protocol can be either more or less efficient than the X-window network protocol, depending on the graphical representation of the data. (author)

  1. Thermic diode performance characteristics and design manual

    Science.gov (United States)

    Bernard, D. E.; Buckley, S.

    1979-01-01

    Thermic diode solar panels are a passive method of space and hot water heating using the thermosyphon principle. Simplified methods of sizing and performing economic analyses of solar heating systems had until now been limited to passive systems. A mathematical model of the thermic diode including its high level of stratification has been constructed allowing its performance characteristics to be studied. Further analysis resulted in a thermic diode design manual based on the f-chart method.

  2. Haematological characteristics and performance of West African ...

    African Journals Online (AJOL)

    The effects of feeding crude petroleum contaminated forage on haematological characteristics and performance of 36 young West African Dwarf (WAD) goats was investigated in order to simulate the impact of real crude oil spillage on livestock and game. Graded levels (0.0, 1.5 and 3.0 g per kg forage) of stabilized “Bonny ...

  3. Growth performance, blood parameters and carcass characteristics ...

    African Journals Online (AJOL)

    This study was carried out with one hundred and twenty (120) day-old marshal chicks to investigate the effect of Maxigrain® enzyme supplementation of corn bran based diets on growth performance, carcass characteristics, haematology and serum biochemistry of broilers in an eight weeks experiment. Four experimental ...

  4. A Bayesian Network to Predict Barrier Island Geomorphologic Characteristics

    Science.gov (United States)

    Gutierrez, B.; Plant, N. G.; Thieler, E. R.; Turecek, A.; Stippa, S.

    2014-12-01

    Understanding how barrier islands along the Atlantic and Gulf coasts of the United States respond to storms and sea-level rise is an important management concern. Although these threats are well recognized, quantifying the integrated vulnerability is challenging due to the range of time and space scalesover which these processes act. Developing datasets and methods to identify the physical vulnerabilities of coastal environments due to storms and sea-level rise thus is an important scientific focus that supports land management decision making. Here we employ a Bayesian Network (BN) to model the interactions between geomorphic variables sampled from existing datasets that capture both storm-and sea-level rise related coastal evolution. The BN provides a means of estimating probabilities of changes in specific geomorphic characteristics such as foredune crest height, beach width, beach height, given knowledge of barrier island width, maximum barrier island elevation, distance from an inlet, the presence of anthropogenic modifications, and long-term shoreline change rates, which we assume to be directly related to sea-level rise. We evaluate BN skill and explore how different constraints, such as shoreline change characteristics (eroding, stable, accreting), distance to nearby inlets and island width, affect the probability distributions of future morphological characteristics. Our work demonstrates that a skillful BN can be constructed and that factors such as distance to inlet, shoreline change rate, and the presence of human alterations have the strongest influences on network performance. For Assateague Island, Maryland/Virginia, USA, we find that different shoreline change behaviors affect the probabilities of specific geomorphic characteristics, such as dune height, which allows us to identify vulnerable locations on the barrier island where habitat or infrastructure may be vulnerable to storms and sea-level rise.

  5. Performance Monitoring Techniques Supporting Cognitive Optical Networking

    DEFF Research Database (Denmark)

    Caballero Jambrina, Antonio; Borkowski, Robert; Zibar, Darko

    2013-01-01

    High degree of heterogeneity of future optical networks, such as services with different quality-of-transmission requirements, modulation formats and switching techniques, will pose a challenge for the control and optimization of different parameters. Incorporation of cognitive techniques can help...... to solve this issue by realizing a network that can observe, act, learn and optimize its performance, taking into account end-to-end goals. In this letter we present the approach of cognition applied to heterogeneous optical networks developed in the framework of the EU project CHRON: Cognitive...... Heterogeneous Reconfigurable Optical Network. We focus on the approaches developed in the project for optical performance monitoring, which enable the feedback from the physical layer to the cognitive decision system by providing accurate description of the performance of the established lightpaths....

  6. Characteristics of file sharing and peer to peer networking | Opara ...

    African Journals Online (AJOL)

    Characteristics of file sharing and peer to peer networking. ... distributing or providing access to digitally stored information, such as computer programs, ... including in multicast systems, anonymous communications systems, and web caches.

  7. Effect of mean network coordination number on dispersivity characteristics

    NARCIS (Netherlands)

    Vasilyev, L.; Raoof, A.; Nordbotten, J.M.

    2012-01-01

    In this study, we investigate the role of topology on the macroscopic (centimeter scale) dispersion characteristics derived from pore-network models.We consider 3D random porous networks extracted from a regular cubic lattice with coordination number distributed in accordance with real porous

  8. How Friendship Network Characteristics Influence Subjective Well-Being

    NARCIS (Netherlands)

    van der Horst, Mariska; Coffé, Hilde

    2012-01-01

    This article explores how friendship network characteristics influence subjective well-being (SWB). Using data from the 2003 General Social Survey of Canada, three components of the friendship network are differentiated: number of friends, frequency of contact, and heterogeneity of friends. We argue

  9. Applying a social network analysis (SNA) approach to understanding radiologists' performance in reading mammograms

    Science.gov (United States)

    Tavakoli Taba, Seyedamir; Hossain, Liaquat; Heard, Robert; Brennan, Patrick; Lee, Warwick; Lewis, Sarah

    2017-03-01

    Rationale and objectives: Observer performance has been widely studied through examining the characteristics of individuals. Applying a systems perspective, while understanding of the system's output, requires a study of the interactions between observers. This research explains a mixed methods approach to applying a social network analysis (SNA), together with a more traditional approach of examining personal/ individual characteristics in understanding observer performance in mammography. Materials and Methods: Using social networks theories and measures in order to understand observer performance, we designed a social networks survey instrument for collecting personal and network data about observers involved in mammography performance studies. We present the results of a study by our group where 31 Australian breast radiologists originally reviewed 60 mammographic cases (comprising of 20 abnormal and 40 normal cases) and then completed an online questionnaire about their social networks and personal characteristics. A jackknife free response operating characteristic (JAFROC) method was used to measure performance of radiologists. JAFROC was tested against various personal and network measures to verify the theoretical model. Results: The results from this study suggest a strong association between social networks and observer performance for Australian radiologists. Network factors accounted for 48% of variance in observer performance, in comparison to 15.5% for the personal characteristics for this study group. Conclusion: This study suggest a strong new direction for research into improving observer performance. Future studies in observer performance should consider social networks' influence as part of their research paradigm, with equal or greater vigour than traditional constructs of personal characteristics.

  10. The Application of Social Characteristic and L1 Optimization in the Error Correction for Network Coding in Wireless Sensor Networks.

    Science.gov (United States)

    Zhang, Guangzhi; Cai, Shaobin; Xiong, Naixue

    2018-02-03

    One of the remarkable challenges about Wireless Sensor Networks (WSN) is how to transfer the collected data efficiently due to energy limitation of sensor nodes. Network coding will increase network throughput of WSN dramatically due to the broadcast nature of WSN. However, the network coding usually propagates a single original error over the whole network. Due to the special property of error propagation in network coding, most of error correction methods cannot correct more than C /2 corrupted errors where C is the max flow min cut of the network. To maximize the effectiveness of network coding applied in WSN, a new error-correcting mechanism to confront the propagated error is urgently needed. Based on the social network characteristic inherent in WSN and L1 optimization, we propose a novel scheme which successfully corrects more than C /2 corrupted errors. What is more, even if the error occurs on all the links of the network, our scheme also can correct errors successfully. With introducing a secret channel and a specially designed matrix which can trap some errors, we improve John and Yi's model so that it can correct the propagated errors in network coding which usually pollute exactly 100% of the received messages. Taking advantage of the social characteristic inherent in WSN, we propose a new distributed approach that establishes reputation-based trust among sensor nodes in order to identify the informative upstream sensor nodes. With referred theory of social networks, the informative relay nodes are selected and marked with high trust value. The two methods of L1 optimization and utilizing social characteristic coordinate with each other, and can correct the propagated error whose fraction is even exactly 100% in WSN where network coding is performed. The effectiveness of the error correction scheme is validated through simulation experiments.

  11. Diversity Performance Analysis on Multiple HAP Networks

    Science.gov (United States)

    Dong, Feihong; Li, Min; Gong, Xiangwu; Li, Hongjun; Gao, Fengyue

    2015-01-01

    One of the main design challenges in wireless sensor networks (WSNs) is achieving a high-data-rate transmission for individual sensor devices. The high altitude platform (HAP) is an important communication relay platform for WSNs and next-generation wireless networks. Multiple-input multiple-output (MIMO) techniques provide the diversity and multiplexing gain, which can improve the network performance effectively. In this paper, a virtual MIMO (V-MIMO) model is proposed by networking multiple HAPs with the concept of multiple assets in view (MAV). In a shadowed Rician fading channel, the diversity performance is investigated. The probability density function (PDF) and cumulative distribution function (CDF) of the received signal-to-noise ratio (SNR) are derived. In addition, the average symbol error rate (ASER) with BPSK and QPSK is given for the V-MIMO model. The system capacity is studied for both perfect channel state information (CSI) and unknown CSI individually. The ergodic capacity with various SNR and Rician factors for different network configurations is also analyzed. The simulation results validate the effectiveness of the performance analysis. It is shown that the performance of the HAPs network in WSNs can be significantly improved by utilizing the MAV to achieve overlapping coverage, with the help of the V-MIMO techniques. PMID:26134102

  12. Diversity Performance Analysis on Multiple HAP Networks

    Directory of Open Access Journals (Sweden)

    Feihong Dong

    2015-06-01

    Full Text Available One of the main design challenges in wireless sensor networks (WSNs is achieving a high-data-rate transmission for individual sensor devices. The high altitude platform (HAP is an important communication relay platform for WSNs and next-generation wireless networks. Multiple-input multiple-output (MIMO techniques provide the diversity and multiplexing gain, which can improve the network performance effectively. In this paper, a virtual MIMO (V-MIMO model is proposed by networking multiple HAPs with the concept of multiple assets in view (MAV. In a shadowed Rician fading channel, the diversity performance is investigated. The probability density function (PDF and cumulative distribution function (CDF of the received signal-to-noise ratio (SNR are derived. In addition, the average symbol error rate (ASER with BPSK and QPSK is given for the V-MIMO model. The system capacity is studied for both perfect channel state information (CSI and unknown CSI individually. The ergodic capacity with various SNR and Rician factors for different network configurations is also analyzed. The simulation results validate the effectiveness of the performance analysis. It is shown that the performance of the HAPs network in WSNs can be significantly improved by utilizing the MAV to achieve overlapping coverage, with the help of the V-MIMO techniques.

  13. Dismissing attachment characteristics dynamically modulate brain networks subserving social aversion.

    Directory of Open Access Journals (Sweden)

    Anna Linda eKrause

    2016-03-01

    Full Text Available Attachment patterns influence actions, thoughts and feeling through a person’s ‘Inner Working Model’. Speech charged with attachment-dependent content was proposed to modulate the activation of cognitive-emotional schemata in listeners. We performed a 7 Tesla rest-task-rest fMRI-experiment, presenting auditory narratives prototypical of dismissing attachment representations to investigate their effect on 23 healthy males. We then examined effects of participants’ attachment style and childhood trauma on brain state changes using seed-based functional connectivity (FC analyses, and finally tested whether subjective differences in responsivity to narratives could be predicted by baseline network states. In comparison to a baseline state, we observed increased FC in a previously described ‘social aversion network’ including dorsal anterior cingulated cortex (dACC and left anterior middle temporal gyrus (aMTG specifically after exposure to insecure-dismissing attachment narratives. Increased dACC-seeded FC within the social aversion network was positively related to the participants’ avoidant attachment style and presence of a history of childhood trauma. Anxious attachment style on the other hand was positively correlated with FC between the dACC and a region outside of the ‘social aversion network’, namely the dorsolateral prefrontal cortex, which suggests decreased network segregation as a function of anxious attachment. Finally, the extent of subjective experience of friendliness towards the dismissing narrative was predicted by low baseline FC-values between hippocampus and inferior parietal lobule. Taken together, our study demonstrates an activation of networks related to social aversion in terms of increased connectivity after listening to insecure-dismissing attachment narratives. A causal interrelation of brain state changes and subsequent changes in social reactivity was further supported by our observation of direct

  14. Integrated System for Performance Monitoring of ATLAS TDAQ Network

    CERN Document Server

    Savu, D; The ATLAS collaboration; Martin, B; Sjoen, R; Batraneanu, S; Stancu, S

    2010-01-01

    The ATLAS TDAQ Network consists of three separate networks spanning four levels of the experimental building. Over 200 edge switches and 5 multi-blade chassis routers are used to interconnect 2000 processors, adding up to more than 7000 high speed interfaces. In order to substantially speed-up ad-hoc and post mortem analysis, a scalable, yet flexible, integrated system for monitoring both network statistics and environmental conditions, processor parameters and data taking characteristics was required. For successful up-to-the-minute monitoring, information from many SNMP compliant devices, independent databases and custom APIs was gathered, stored and displayed in an optimal way. Easy navigation and compact aggregation of multiple data sources were the main requirements; characteristics not found in any of the tested products, either open-source or commercial. This paper describes how performance, scalability and display issues were addressed and what challenges the project faced during development and deplo...

  15. TCP Performance Enhancement for UMTS Access Network

    DEFF Research Database (Denmark)

    Hu, Liang

    2008-01-01

    is between UMTS access network and Internet. The split proxy divides the bandwidth delay product into two parts, resulting in two TCP connections with smaller bandwidth delay products. Simulation results show, the split TCP proxy can significantly improve the TCP performance under high bit rate DCH channel......We aim at optimize the TCP performance over UMTS access network challenged by the large delay bandwidth product that is mainly caused by the latency from the link layer ARQ retransmissions and diversity technique at physical layer. We propose to place a split TCP proxy at GGSN nodes which...

  16. Planning Multitechnology Access Networks with Performance Constraints

    Science.gov (United States)

    Chamberland, Steven

    Considering the number of access network technologies and the investment needed for the “last mile” of a solution, in today’s highly competitive markets, planning tools are crucial for the service providers to optimize the network costs and accelerate the planning process. In this paper, we propose to tackle the problem of planning access networks composed of four technologies/architectures: the digital subscriber line (xDSL) technologies deployed directly from the central office (CO), the fiber-to-the-node (FTTN), the fiber-to-the-micro-node (FTTn) and the fiber-to-the-premises (FTTP). A mathematical programming model is proposed for this planning problem that is solved using a commercial implementation of the branch-and-bound algorithm. Next, a detailed access network planning example is presented followed by a systematic set of experiments designed to assess the performance of the proposed approach.

  17. Performance of social network sensors during Hurricane Sandy.

    Directory of Open Access Journals (Sweden)

    Yury Kryvasheyeu

    Full Text Available Information flow during catastrophic events is a critical aspect of disaster management. Modern communication platforms, in particular online social networks, provide an opportunity to study such flow and derive early-warning sensors, thus improving emergency preparedness and response. Performance of the social networks sensor method, based on topological and behavioral properties derived from the "friendship paradox", is studied here for over 50 million Twitter messages posted before, during, and after Hurricane Sandy. We find that differences in users' network centrality effectively translate into moderate awareness advantage (up to 26 hours; and that geo-location of users within or outside of the hurricane-affected area plays a significant role in determining the scale of such an advantage. Emotional response appears to be universal regardless of the position in the network topology, and displays characteristic, easily detectable patterns, opening a possibility to implement a simple "sentiment sensing" technique that can detect and locate disasters.

  18. Performance of Social Network Sensors during Hurricane Sandy

    Science.gov (United States)

    Kryvasheyeu, Yury; Chen, Haohui; Moro, Esteban; Van Hentenryck, Pascal; Cebrian, Manuel

    2015-01-01

    Information flow during catastrophic events is a critical aspect of disaster management. Modern communication platforms, in particular online social networks, provide an opportunity to study such flow and derive early-warning sensors, thus improving emergency preparedness and response. Performance of the social networks sensor method, based on topological and behavioral properties derived from the “friendship paradox”, is studied here for over 50 million Twitter messages posted before, during, and after Hurricane Sandy. We find that differences in users’ network centrality effectively translate into moderate awareness advantage (up to 26 hours); and that geo-location of users within or outside of the hurricane-affected area plays a significant role in determining the scale of such an advantage. Emotional response appears to be universal regardless of the position in the network topology, and displays characteristic, easily detectable patterns, opening a possibility to implement a simple “sentiment sensing” technique that can detect and locate disasters. PMID:25692690

  19. Performance Analysis of IIUM Wireless Campus Network

    International Nuclear Information System (INIS)

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

    2013-01-01

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

  20. Characteristics and performances of electronic personal dosemeters

    International Nuclear Information System (INIS)

    Aubert, B.

    2002-01-01

    The regulations have made obligation for 2 years to measure and analyse the amounts of radiations actually received during an operation. The whole of these measurements taken uninterrupted for an immediate reading is indicated like the operational dosimetry, which is carried out with the means of personal electronic dosemeters. This study analyses the legislation relating to this type of dosimetry as well as the requirements in medical environment, and presents an assessment of the characteristics and performances of the devices available on the French market at the beginning of 2002 starting from the information provided by the various manufacturers. (author)

  1. NetBench. Automated Network Performance Testing

    CERN Document Server

    Cadeddu, Mattia

    2016-01-01

    In order to evaluate the operation of high performance routers, CERN has developed the NetBench software to run benchmarking tests by injecting various traffic patterns and observing the network devices behaviour in real-time. The tool features a modular design with a Python based console used to inject traffic and collect the results in a database, and a web user

  2. Estimating cellular network performance during hurricanes

    International Nuclear Information System (INIS)

    Booker, Graham; Torres, Jacob; Guikema, Seth; Sprintson, Alex; Brumbelow, Kelly

    2010-01-01

    Cellular networks serve a critical role during and immediately after a hurricane, allowing citizens to contact emergency services when land-line communication is lost and serving as a backup communication channel for emergency responders. However, due to their ubiquitous deployment and limited design for extreme loading events, basic network elements, such as cellular towers and antennas are prone to failures during adverse weather conditions such as hurricanes. Accordingly, a systematic and computationally feasible approach is required for assessing and improving the reliability of cellular networks during hurricanes. In this paper we develop a new multi-disciplinary approach to efficiently and accurately assess cellular network reliability during hurricanes. We show how the performance of a cellular network during and immediately after future hurricanes can be estimated based on a combination of hurricane wind field models, structural reliability analysis, Monte Carlo simulation, and cellular network models and simulation tools. We then demonstrate the use of this approach for assessing the improvement in system reliability that can be achieved with discrete topological changes in the system. Our results suggest that adding redundancy, particularly through a mesh topology or through the addition of an optical fiber ring around the perimeter of the system can be an effective way to significantly increase the reliability of some cellular systems during hurricanes.

  3. Impact Of Firewall On Network Performance

    Directory of Open Access Journals (Sweden)

    Francis Kwadzo Agbenyegah

    2017-03-01

    Full Text Available This research work investigated the firewall security and performance relationship for distributed systems. Internet connectivity is growing with most enterprises migrating to the use of web based services for services provision. As organization grab the Internet as another business tool whether to sell to team up or to communicate - web applications have turned into the new weakest connection in the organizations security technique. Firewalls provide a mechanism for protecting these enterprises from the less secure internet over which customers or collaborating partners transfer packets destined for the corporate network. The connection between the security and execution proficiency is exhibited through distinctive scenarios and the relationship between security and performance in firewalls is assessed. We demonstrated distinctive networks with and without firewalls and diverse firewall functionality and simulated such systems with an eye on their performance. The simulation was done for 300 work stations and simulated in a way that all the 300 work stations access an email and web application under three different scenarios. Attention is on the relationship between system security and performance the impacts of firewalls on system execution. Different scenarios were assessed through simulations utilizing OPNET IT Guru Academic Edition 9.1 to demonstrate the impacts of firewalls on system performance. The result shows that maintaining security which involves the utilization of numerous applications and the use of firewall has an effect on network performance.

  4. THE USE OF NEURAL NETWORK TECHNOLOGY TO MODEL SWIMMING PERFORMANCE

    Directory of Open Access Journals (Sweden)

    António José Silva

    2007-03-01

    Full Text Available The aims of the present study were: to identify the factors which are able to explain the performance in the 200 meters individual medley and 400 meters front crawl events in young swimmers, to model the performance in those events using non-linear mathematic methods through artificial neural networks (multi-layer perceptrons and to assess the neural network models precision to predict the performance. A sample of 138 young swimmers (65 males and 73 females of national level was submitted to a test battery comprising four different domains: kinanthropometric evaluation, dry land functional evaluation (strength and flexibility, swimming functional evaluation (hydrodynamics, hydrostatic and bioenergetics characteristics and swimming technique evaluation. To establish a profile of the young swimmer non-linear combinations between preponderant variables for each gender and swim performance in the 200 meters medley and 400 meters font crawl events were developed. For this purpose a feed forward neural network was used (Multilayer Perceptron with three neurons in a single hidden layer. The prognosis precision of the model (error lower than 0.8% between true and estimated performances is supported by recent evidence. Therefore, we consider that the neural network tool can be a good approach in the resolution of complex problems such as performance modeling and the talent identification in swimming and, possibly, in a wide variety of sports

  5. A review of hospital characteristics associated with improved performance.

    Science.gov (United States)

    Brand, Caroline A; Barker, Anna L; Morello, Renata T; Vitale, Michael R; Evans, Sue M; Scott, Ian A; Stoelwinder, Johannes U; Cameron, Peter A

    2012-10-01

    The objective of this review was to critically appraise the literature relating to associations between high-level structural and operational hospital characteristics and improved performance. The Cochrane Library, MEDLINE (Ovid), CINAHL, proQuest and PsychINFO were searched for articles published between January 1996 and May 2010. Reference lists of included articles were reviewed and key journals were hand searched for relevant articles. and data extraction Studies were included if they were systematic reviews or meta-analyses, randomized controlled trials, controlled before and after studies or observational studies (cohort and cross-sectional) that were multicentre, comparative performance studies. Two reviewers independently extracted data, assigned grades of evidence according to the Australian National Health and Medical Research Council guidelines and critically appraised the included articles. Data synthesis Fifty-seven studies were reported within 12 systematic reviews and 47 observational articles. There was heterogeneity in use and definition of performance outcomes. Hospital characteristics investigated were environment (incentives, market characteristics), structure (network membership, ownership, teaching status, geographical setting, service size) and operational design (innovativeness, leadership, organizational culture, public reporting and patient safety practices, information technology systems and decision support, service activity and planning, workforce design, staff training and education). The strongest evidence for an association with overall performance was identified for computerized physician order entry systems. Some evidence supported the associations with workforce design, use of financial incentives, nursing leadership and hospital volume. There is limited, mainly low-quality evidence, supporting the associations between hospital characteristics and healthcare performance. Further characteristic-specific systematic reviews are

  6. Characteristics explaining performance in downhill mountain biking.

    Science.gov (United States)

    Chidley, Joel B; MacGregor, Alexandra L; Martin, Caoimhe; Arthur, Calum A; Macdonald, Jamie H

    2015-03-01

    To identify physiological, psychological, and skill characteristics that explain performance in downhill (DH) mountain-bike racing. Four studies were used to (1) identify factors potentially contributing to DH performance (using an expert focus group), (2) develop and validate a measure of rider skill (using video analysis and expert judge evaluation), (3) evaluate whether physiological, psychological, and skill variables contribute to performance at a DH competition, and (4) test the specific contribution of aerobic capacity to DH performance. STUDY 1 identified aerobic capacity, handgrip endurance, anaerobic power, rider skill, and self-confidence as potentially important for DH. In study 2 the rider-skill measure displayed good interrater reliability. Study 3 found that rider skill and handgrip endurance were significantly related to DH ride time (β=-0.76 and -0.14, respectively; R2=.73), with exploratory analyses suggesting that DH ride time may also be influenced by self-confidence and aerobic capacity. Study 4 confirmed aerobic capacity as an important variable influencing DH performance (for a DH ride, mean oxygen uptake was 49±5 mL·kg(-1)·min(-1), and 90% of the ride was completed above the 1st ventilatory threshold). In order of importance, rider skill, handgrip endurance, self-confidence, and aerobic capacity were identified as variables influencing DH performance. Practically, this study provides a novel assessment of rider skill that could be used by coaches to monitor training and identify talent. Novel intervention targets to enhance DH performance were also identified, including self-confidence and aerobic capacity.

  7. Performance modeling, stochastic networks, and statistical multiplexing

    CERN Document Server

    Mazumdar, Ravi R

    2013-01-01

    This monograph presents a concise mathematical approach for modeling and analyzing the performance of communication networks with the aim of introducing an appropriate mathematical framework for modeling and analysis as well as understanding the phenomenon of statistical multiplexing. The models, techniques, and results presented form the core of traffic engineering methods used to design, control and allocate resources in communication networks.The novelty of the monograph is the fresh approach and insights provided by a sample-path methodology for queueing models that highlights the importan

  8. Evolution characteristics of the network core in the Facebook.

    Directory of Open Access Journals (Sweden)

    Jian-Guo Liu

    Full Text Available Statistical properties of the static networks have been extensively studied. However, online social networks are evolving dynamically, understanding the evolving characteristics of the core is one of major concerns in online social networks. In this paper, we empirically investigate the evolving characteristics of the Facebook core. Firstly, we separate the Facebook-link(FL and Facebook-wall(FW datasets into 28 snapshots in terms of timestamps. By employing the k-core decomposition method to identify the core of each snapshot, we find that the core sizes of the FL and FW networks approximately contain about 672 and 373 nodes regardless of the exponential growth of the network sizes. Secondly, we analyze evolving topological properties of the core, including the k-core value, assortative coefficient, clustering coefficient and the average shortest path length. Empirical results show that nodes in the core are getting more interconnected in the evolving process. Thirdly, we investigate the life span of nodes belonging to the core. More than 50% nodes stay in the core for more than one year, and 19% nodes always stay in the core from the first snapshot. Finally, we analyze the connections between the core and the whole network, and find that nodes belonging to the core prefer to connect nodes with high k-core values, rather than the high degrees ones. This work could provide new insights into the online social network analysis.

  9. Hamlet, Performance and Chaotic Cultural Networks

    Directory of Open Access Journals (Sweden)

    Emil Rybczak

    2015-10-01

    Full Text Available Since the 1960s, chaos theory has become an important but controversial tool used by scientists and mathematicians to describe physical or theoretical systems or networks. It explains how the simple can generate the complex. Its central tenets can also provide an alternative language and means of literary interpretation. This article will explore how the principles of chaos theory can be used to close read and systematise various aspects of the language and performance of Shakespeare. The argument is built upon an analysis of Hamlet, in an effort to understand the play and its reproduction as the evolution of interconnected complex networks. Various aspects of the text will be discussed, including its language, structural and character patterning, and its reproduction through performance and cinematic adaptation. Each of these topics, and the characters, devices or ideas they discuss, constitute nodes of the complex network of Hamlet as both text and idea. Responding to the cultural analysis of other scholars, this article uses Hamlet as an ideal example of how the appropriation of scientific language can defamiliarise a particular literary or dramatic artefact. This allows fresh interpretation and understanding of its location within the broader networks of theatre and culture. I suggest the possibilities of close reading literary works through the lens of chaos and suggest how they might be applied and developed in conjunction with other texts, media or performances.

  10. Performance Analysis of RF-FSO Multi-Hop Networks

    KAUST Repository

    Makki, Behrooz

    2017-05-12

    We study the performance of multi-hop networks composed of millimeter wave (MMW)-based radio frequency (RF) and free-space optical (FSO) links. The results are obtained in the cases with and without hybrid automatic repeat request (HARQ). Taking the MMW characteristics of the RF links into account, we derive closed-form expressions for the network outage probability. We also evaluate the effect of various parameters such as power amplifiers efficiency, number of antennas as well as different coherence times of the RF and the FSO links on the system performance. Finally, we present mappings between the performance of RF- FSO multi-hop networks and the ones using only the RF- or the FSO-based communication, in the sense that with appropriate parameter settings the same outage probability is achieved in these setups. The results show the efficiency of the RF-FSO setups in different conditions. Moreover, the HARQ can effectively improve the outage probability/energy efficiency, and compensate the effect of hardware impairments in RF-FSO networks. For common parameter settings of the RF-FSO dual- hop networks, outage probability 10^{-4} and code rate 3 nats-per-channel-use, the implementation of HARQ with a maximum of 2 and 3 retransmissions reduces the required power, compared to the cases with no HARQ, by 13 and 17 dB, respectively.

  11. The Effects of Nonperforming Loans on Dynamic Network Bank Performance

    Directory of Open Access Journals (Sweden)

    Day-Yang Liu

    2017-01-01

    Full Text Available This paper is to explore the relationship between banks’ performance and their nonperforming loans (NPLs. The banks’ performance through a network production process structure with NPLs is developed. With increasing NPLs in recent years, the quality of lending assets is a key significant and influencing factor for banks’ operational risk. The research methodology is to integrate the radial and nonradial measures of efficiency into the network production process framework with NPLs; this study utilizes network epsilon-based measure model to evaluate the banking industry performance. In addition, the key characteristics of the bank industry including those of financial holding companies and privatized government banks are needed to be figured out and to provide insight into what causes imperfectly competitive conditions for some banks. The results demonstrate that the banking sector grew consistently in three aspects of operation: operating performance, profitability performance, and risk management in the last five years of the subject period. These results showed that the overall banking sector was capable of pursuing growth in both operations and profits while accounting for risk management. The potential applications and strengths of network data envelopment analysis in assessing financial organizations are also highlighted.

  12. Integrated healthcare networks' performance: a growth curve modeling approach.

    Science.gov (United States)

    Wan, Thomas T H; Wang, Bill B L

    2003-05-01

    This study examines the effects of integration on the performance ratings of the top 100 integrated healthcare networks (IHNs) in the United States. A strategic-contingency theory is used to identify the relationship of IHNs' performance to their structural and operational characteristics and integration strategies. To create a database for the panel study, the top 100 IHNs selected by the SMG Marketing Group in 1998 were followed up in 1999 and 2000. The data were merged with the Dorenfest data on information system integration. A growth curve model was developed and validated by the Mplus statistical program. Factors influencing the top 100 IHNs' performance in 1998 and their subsequent rankings in the consecutive years were analyzed. IHNs' initial performance scores were positively influenced by network size, number of affiliated physicians and profit margin, and were negatively associated with average length of stay and technical efficiency. The continuing high performance, judged by maintaining higher performance scores, tended to be enhanced by the use of more managerial or executive decision-support systems. Future studies should include time-varying operational indicators to serve as predictors of network performance.

  13. Networks, Micro Small Enterprises (MSE'S) and Performance: the ...

    African Journals Online (AJOL)

    Networks, Micro Small Enterprises (MSE'S) and Performance: the Case of Kenya. ... It adopts the network perspective theoretical approach. Empirically, the ... entrepreneurial personal network as a copying strategy in the process of global

  14. A Fluid Model for Performance Analysis in Cellular Networks

    Directory of Open Access Journals (Sweden)

    Coupechoux Marceau

    2010-01-01

    Full Text Available We propose a new framework to study the performance of cellular networks using a fluid model and we derive from this model analytical formulas for interference, outage probability, and spatial outage probability. The key idea of the fluid model is to consider the discrete base station (BS entities as a continuum of transmitters that are spatially distributed in the network. This model allows us to obtain simple analytical expressions to reveal main characteristics of the network. In this paper, we focus on the downlink other-cell interference factor (OCIF, which is defined for a given user as the ratio of its outer cell received power to its inner cell received power. A closed-form formula of the OCIF is provided in this paper. From this formula, we are able to obtain the global outage probability as well as the spatial outage probability, which depends on the location of a mobile station (MS initiating a new call. Our analytical results are compared to Monte Carlo simulations performed in a traditional hexagonal network. Furthermore, we demonstrate an application of the outage probability related to cell breathing and densification of cellular networks.

  15. Performance modeling, loss networks, and statistical multiplexing

    CERN Document Server

    Mazumdar, Ravi

    2009-01-01

    This monograph presents a concise mathematical approach for modeling and analyzing the performance of communication networks with the aim of understanding the phenomenon of statistical multiplexing. The novelty of the monograph is the fresh approach and insights provided by a sample-path methodology for queueing models that highlights the important ideas of Palm distributions associated with traffic models and their role in performance measures. Also presented are recent ideas of large buffer, and many sources asymptotics that play an important role in understanding statistical multiplexing. I

  16. Statistical characteristics of serious network failures in Japan

    International Nuclear Information System (INIS)

    Uchida, Masato

    2014-01-01

    Due to significant environmental changes in the telecommunications market, network failures affect socioeconomic activities more than ever before. However, the health of public networks at a national level has not been investigated in detail. In this paper, we investigate the statistical characteristics of interval, duration, and the number of users affected for serious network failures, which are defined as network failures that last for more than two hours and affect more than 30,000 users, that occurred in Japan during Japanese fiscal years 2008–2012 (April 2008–March 2013). The results show that (i) the interval follows a Poisson process, (ii) the duration follows a Pareto distribution, (iii) the number of users affected follows a piecewise Pareto distribution, (iv) the product of duration and the number of users affected roughly follow a distribution that can be derived from a convolution of two distributions of duration and the number of users affected, and (v) the relationship between duration and the number of users affected differs from service to service. - Highlights: • The statistical characteristics of serious network failures in Japan are analyzed. • The analysis is based on public information that is available at the moment. • The interval follows a Poisson process. • The duration follows a Pareto distribution. • The number of users affected follows a piecewise Pareto distribution

  17. Characteristics of Key Update Strategies for Wireless Sensor Networks

    DEFF Research Database (Denmark)

    Yuksel, Ender; Nielson, Hanne Riis; Nielson, Flemming

    2011-01-01

    Wireless sensor networks offer the advantages of simple and low-resource communication. Challenged by this simplicity and low-resources, security is of particular importance in many cases such as transmission of sensitive data or strict requirements of tamper-resistance. Updating the security keys...... is one of the essential points in security, which restrict the amount of data that may be exposed when a key is compromised. In this paper, we investigate key update methods that may be used in wireless sensor networks, and benefiting from stochastic model checking we derive characteristics...

  18. Learning characteristics of a space-time neural network as a tether skiprope observer

    Science.gov (United States)

    Lea, Robert N.; Villarreal, James A.; Jani, Yashvant; Copeland, Charles

    1993-01-01

    The Software Technology Laboratory at the Johnson Space Center is testing a Space Time Neural Network (STNN) for observing tether oscillations present during retrieval of a tethered satellite. Proper identification of tether oscillations, known as 'skiprope' motion, is vital to safe retrieval of the tethered satellite. Our studies indicate that STNN has certain learning characteristics that must be understood properly to utilize this type of neural network for the tethered satellite problem. We present our findings on the learning characteristics including a learning rate versus momentum performance table.

  19. An Analysis of Network and Sensor Performance Within IEEE 802.X Wireless MESH Networks in the Tactical Network Topology (TNT)

    National Research Council Canada - National Science Library

    Davis, Joseph A., Sr

    2005-01-01

    .... Specifically, this thesis will attempt establish the foundation for the development of wireless MESH "network health" models by examining the performance of sensors operating within a MESH network...

  20. Nanotechnological inventions considerably improve performance characteristics

    Directory of Open Access Journals (Sweden)

    VLASOV Vladimir Alexeevich

    2014-06-01

    Full Text Available The invention «The method of production of carbon nanomaterial (RU 2509053» can be used as an additive for concretes and polymers which significantly improves their performance characteristics. The method of production of carbon nanomaterial consists of the following stages: preliminary preparation of sphagnous moss when it is refined from foreign admixtures, dried up to 10% humidity and ground, then ground material is exposed to pyrolysis under the temperature 850–950оC for 1–2 hours and cooled up to the environment temperature. After that amorphous carbon obtained in pyrolysis is treated with mechanical activation in the variable planetary mill for 7–10 hours. The invention makes it possible to provide increased outcome of nanotubes with high cleanliness. The invention «The method of production of nanodispersed metal powders and alloys of them (RU 2509626» relates to the powder metallurgy. Powder metal chloride or powder mixture at least of two metal chlorides is treated in the environment of the water steam which is supplied in reaction space at the rate of 50–100 ml/min at the temperature 400–800оC at the presence of absorbent carbon or introducing carbon oxide (II obtained during dissolution of formic acid HCOOH. The invention provides reliable production of nanodispersed metal powders and alloys of them from 3-d metal range: Ni, Co, Cu, Fe, Zn which can be used in powder metallurgy to improve baking process, in chemical industry as the fillers of polymers and reaction catalysts; as additives to anticorrosive covers, etc.

  1. Data center networks topologies, architectures and fault-tolerance characteristics

    CERN Document Server

    Liu, Yang; Veeraraghavan, Malathi; Lin, Dong; Hamdi, Mounir

    2013-01-01

    This SpringerBrief presents a survey of data center network designs and topologies and compares several properties in order to highlight their advantages and disadvantages. The brief also explores several routing protocols designed for these topologies and compares the basic algorithms to establish connections, the techniques used to gain better performance, and the mechanisms for fault-tolerance. Readers will be equipped to understand how current research on data center networks enables the design of future architectures that can improve performance and dependability of data centers. This con

  2. The Banat seismic network: Evolution and performance

    International Nuclear Information System (INIS)

    Oros, E.

    2002-01-01

    In the Banat Seismic Region, with its important seismogenic zones (Banat and Danube), operates today the Banat Seismic Network. This network has four short period seismic stations telemetered at the Timisoara Seismological Observatory (since 1995): Siria, Banloc, Buzias and Timisoara. The stations are equipped with short-period S13 seismometers (1 second). The data recorded by the short-period stations are telemetered to Timisoara where they are digitized at 50 samples per second, with 16 bit resolution. At Timisoara works SAPS, an automated system for data acquisition and processing, which performs real-time event detection (based on Allen algorithm), discrimination between local and teleseismic events, automatic P and S waves picking, location and magnitude determination for local events and teleseisms, 'feeding' of an Automatic Data Request Manager with phases, locations and waveforms, sending of earthquake information (as phases and location), by e-mail to Bucharest. The beginning of the seismological observations in Banat is in the 1880's (Timisoara Meteorological Observatory). The first seismograph was installed in Timisoara in 1901, and its systematic observations began in 1902. The World War I interrupted its work. In 1942 Prof. I. Curea founded the Seismic Station Timisoara, and since 1967 until today this station worked into a special building. After 1972 two stations with high amplification were installed in Retezat Mts (Gura Zlata) and on Nera Valey (Susara), as a consequence of the research results. Since 1982 Buzias station began to work completing the Banat Seismic Network. Therefore, the network could detect and locate any local seismic event with M > 2.2. Moreover, up to 20 km distance from each station any seismic event could be detected over M = 0.5. The paper also presents the quality of the locations versus different local seismic sources. (author)

  3. Performance Evaluation Of Mobile Cellular Networks In Nigeria

    OpenAIRE

    Shoewu, O.O

    2018-01-01

    The aim of this paper is to evaluate the performance of mobile networks such as MTN, GLO, and ETISALAT in Nigeria and suggest ways the performance of digital cellular networks can improve to minimize some of its present short comings or limitations. This paper discusses the performance improvement of digital cellular networks. A non- CDMA cellular network is use in an overall wireless environment for the purpose of this paper. This paper also discusses the performance assessment of three mobi...

  4. Copercolating Networks: An Approach for Realizing High-Performance Transparent Conductors using Multicomponent Nanostructured Networks

    Directory of Open Access Journals (Sweden)

    Das Suprem R.

    2016-06-01

    Full Text Available Although transparent conductive oxides such as indium tin oxide (ITO are widely employed as transparent conducting electrodes (TCEs for applications such as touch screens and displays, new nanostructured TCEs are of interest for future applications, including emerging transparent and flexible electronics. A number of twodimensional networks of nanostructured elements have been reported, including metallic nanowire networks consisting of silver nanowires, metallic carbon nanotubes (m-CNTs, copper nanowires or gold nanowires, and metallic mesh structures. In these single-component systems, it has generally been difficult to achieve sheet resistances that are comparable to ITO at a given broadband optical transparency. A relatively new third category of TCEs consisting of networks of 1D-1D and 1D-2D nanocomposites (such as silver nanowires and CNTs, silver nanowires and polycrystalline graphene, silver nanowires and reduced graphene oxide have demonstrated TCE performance comparable to, or better than, ITO. In such hybrid networks, copercolation between the two components can lead to relatively low sheet resistances at nanowire densities corresponding to high optical transmittance. This review provides an overview of reported hybrid networks, including a comparison of the performance regimes achievable with those of ITO and single-component nanostructured networks. The performance is compared to that expected from bulk thin films and analyzed in terms of the copercolation model. In addition, performance characteristics relevant for flexible and transparent applications are discussed. The new TCEs are promising, but significant work must be done to ensure earth abundance, stability, and reliability so that they can eventually replace traditional ITO-based transparent conductors.

  5. On the Geometrical Characteristics of Three-Dimensional Wireless Ad Hoc Networks and Their Applications

    Directory of Open Access Journals (Sweden)

    2006-01-01

    Full Text Available In a wireless ad hoc network, messages are transmitted, received, and forwarded in a finite geometrical region and the transmission of messages is highly dependent on the locations of the nodes. Therefore the study of geometrical relationship between nodes in wireless ad hoc networks is of fundamental importance in the network architecture design and performance evaluation. However, most previous works concentrated on the networks deployed in the two-dimensional region or in the infinite three-dimensional space, while in many cases wireless ad hoc networks are deployed in the finite three-dimensional space. In this paper, we analyze the geometrical characteristics of the three-dimensional wireless ad hoc network in a finite space in the framework of random graph and deduce an expression to calculate the distance probability distribution between network nodes that are independently and uniformly distributed in a finite cuboid space. Based on the theoretical result, we present some meaningful results on the finite three-dimensional network performance, including the node degree and the max-flow capacity. Furthermore, we investigate some approximation properties of the distance probability distribution function derived in the paper.

  6. Analysis of interference performance of tactical radio network

    Science.gov (United States)

    Nie, Hao; Cai, Xiaoxia; Chen, Hong

    2017-08-01

    Mobile Ad hoc network has a strong military background for its development as the core technology of the backbone network of US tactical Internet. And which tactical radio network, is the war in today's tactical use of the Internet more mature form of networking, mainly used in brigade and brigade following forces. This paper analyzes the typical protocol AODV in the tactical radio network, and then carries on the networking. By adding the interference device to the whole network, the battlefield environment is simulated, and then the throughput, delay and packet loss rate are analyzed, and the performance of the whole network and the single node before and after the interference is obtained.

  7. Modeling the Effect of Bandwidth Allocation on Network Performance

    African Journals Online (AJOL)

    ... The proposed model showed improved performance for CDMA networks, but further increase in the bandwidth did not benefit the network; (iii) A reliability measure such as the spectral efficiency is therefore useful to redeem the limitation in (ii). Keywords: Coverage Capacity, CDMA, Mobile Network, Network Throughput ...

  8. 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.

  9. Destination Characteristics that Drive Hotel Performance

    DEFF Research Database (Denmark)

    Assaf, A. George; Josiassen, Alexander; Woo, Linda

    2017-01-01

    , government support, disposable income, and number of international arrivals within a tourism destination. Results indicate that the most important barriers to hotel performance are the competition among accommodation providers, tax rate and fuel price. We argue for the need for hotel providers to develop......The increased market saturation and competition in both domestic and international tourism destinations have renewed interest among hotel operators in identifying the key drivers of hotel performance. This paper presents a comprehensive analysis of the determinants of hotel performance...... strategies that take cognisance of the key drivers and barriers to enhancing hotel performance in an ever-changing global tourism sector....

  10. Network characteristics emerging from agent interactions in balanced distributed system.

    Science.gov (United States)

    Salman, Mahdi Abed; Bertelle, Cyrille; Sanlaville, Eric

    2015-01-01

    A distributed computing system behaves like a complex network, the interactions between nodes being essential information exchanges and migrations of jobs or services to execute. These actions are performed by software agents, which behave like the members of social networks, cooperating and competing to obtain knowledge and services. The load balancing consists in distributing the load evenly between system nodes. It aims at enhancing the resource usage. A load balancing strategy specifies scenarios for the cooperation. Its efficiency depends on quantity, accuracy, and distribution of available information. Nevertheless, the distribution of information on the nodes, together with the initial network structure, may create different logical network structures. In this paper, different load balancing strategies are tested on different network structures using a simulation. The four tested strategies are able to distribute evenly the load so that the system reaches a steady state (the mean response time of the jobs is constant), but it is shown that a given strategy indeed behaves differently according to structural parameters and information spreading. Such a study, devoted to distributed computing systems (DCSs), can be useful to understand and drive the behavior of other complex systems.

  11. Network performance and fault analytics for LTE wireless service providers

    CERN Document Server

    Kakadia, Deepak; Gilgur, Alexander

    2017-01-01

     This book is intended to describe how to leverage emerging technologies big data analytics and SDN, to address challenges specific to LTE and IP network performance and fault management data in order to more efficiently manage and operate an LTE wireless networks. The proposed integrated solutions permit the LTE network service provider to operate entire integrated network, from RAN to Core , from UE to application service, as one unified system and correspondingly collect and align disparate key metrics and data, using an integrated and holistic approach to network analysis. The LTE wireless network performance and fault involves the network performance and management of network elements in EUTRAN, EPC and IP transport components, not only as individual components, but also as nuances of inter-working of these components. The key metrics for EUTRAN include radio access network accessibility, retainability, integrity, availability and mobility. The key metrics for EPC include MME accessibility, mobility and...

  12. Network characteristics for server selection in online games

    Science.gov (United States)

    Claypool, Mark

    2008-01-01

    Online gameplay is impacted by the network characteristics of players connected to the same server. Unfortunately, the network characteristics of online game servers are not well-understood, particularly for groups that wish to play together on the same server. As a step towards a remedy, this paper presents analysis of an extensive set of measurements of game servers on the Internet. Over the course of many months, actual Internet game servers were queried simultaneously by twenty-five emulated game clients, with both servers and clients spread out on the Internet. The data provides statistics on the uptime and populations of game servers over a month long period an an in-depth look at the suitability for game servers for multi-player server selection, concentrating on characteristics critical to playability--latency and fairness. Analysis finds most game servers have latencies suitable for third-person and omnipresent games, such as real-time strategy, sports and role-playing games, providing numerous server choices for game players. However, far fewer game servers have the low latencies required for first-person games, such as shooters or race games. In all cases, groups that wish to play together have a greatly reduced set of servers from which to choose because of inherent unfairness in server latencies and server selection is particularly limited as the group size increases. These results hold across different game types and even across different generations of games. The data should be useful for game developers and network researchers that seek to improve game server selection, whether for single or multiple players.

  13. IMPACT OF SOCIAL NETWORK STRUCTURE ON EMPLOYEE PERFORMANCE: A COMPARATIVE STUDY

    Directory of Open Access Journals (Sweden)

    Claudio Lira Meirelles

    2013-12-01

    Full Text Available This research sought to understand the relationship between the position of the central actor and the performance of a network, checking the influence of the central actor's performance over other actors. Among the specific objectives, we sought to describe the transactional content, the nature of the connections and the structural characteristics of the network. Data were collected through a questionnaire and analyzed with the help of software UCINET 6.0 and Excel. The results suggest that the performance of the actors with the highest levels of centrality is related to the performance of the actors of the 1st step of sub-networks of these central actors.

  14. Scholastic performance and functional connectivity of brain networks in children.

    Directory of Open Access Journals (Sweden)

    Laura Chaddock-Heyman

    Full Text Available One of the keys to understanding scholastic success is to determine the neural processes involved in school performance. The present study is the first to use a whole-brain connectivity approach to explore whether functional connectivity of resting state brain networks is associated with scholastic performance in seventy-four 7- to 9-year-old children. We demonstrate that children with higher scholastic performance across reading, math and language have more integrated and interconnected resting state networks, specifically the default mode network, salience network, and frontoparietal network. To add specificity, core regions of the dorsal attention and visual networks did not relate to scholastic performance. The results extend the cognitive role of brain networks in children as well as suggest the importance of network connectivity in scholastic success.

  15. Haematological characteristics and performance of West African ...

    African Journals Online (AJOL)

    STORAGESEVER

    2009-02-18

    Feb 18, 2009 ... ISSN 1684–5315 © 2009 Academic Journals. Full Length ... performance of 36 young West African Dwarf (WAD) goats was investigated in order to simulate the .... cause antibody depression, alter white blood cell counts,.

  16. Sire influence on reproductive, performance characteristics and ...

    African Journals Online (AJOL)

    , Panda White x Cinnamon Brown (PWxCB) and Silver Brown x Cinnamon Brown (SBxCB). The experiment was a randomized complete block design. Parameters measured include: fertility and hatchability traits, growth performance traits and ...

  17. Performance of networks of artificial neurons: The role of clustering

    International Nuclear Information System (INIS)

    Kim, Beom Jun

    2004-01-01

    The performance of the Hopfield neural network model is numerically studied on various complex networks, such as the Watts-Strogatz network, the Barabasi-Albert network, and the neuronal network of Caenorhabditis elegans. Through the use of a systematic way of controlling the clustering coefficient, with the degree of each neuron kept unchanged, we find that the networks with the lower clustering exhibit much better performance. The results are discussed in the practical viewpoint of application, and the biological implications are also suggested

  18. Data characteristics that determine classifier performance

    CSIR Research Space (South Africa)

    Van der Walt, Christiaan M

    2006-11-01

    Full Text Available available at [11]. The kNN uses a LinearNN nearest neighbour search algorithm with an Euclidean distance metric [8]. The optimal k value is determined by performing 10-fold cross-validation. An optimal k value between 1 and 10 is used for Experiments 1... classifiers. 10-fold cross-validation is used to evaluate and compare the performance of the classifiers on the different data sets. 3.1. Artificial data generation Multivariate Gaussian distributions are used to generate artificial data sets. We use d...

  19. Coexistence: Threat to the Performance of Heterogeneous Network

    Science.gov (United States)

    Sharma, Neetu; Kaur, Amanpreet

    2010-11-01

    Wireless technology is gaining broad acceptance as users opt for the freedom that only wireless network can provide. Well-accepted wireless communication technologies generally operate in frequency bands that are shared among several users, often using different RF schemes. This is true in particular for WiFi, Bluetooth, and more recently ZigBee. These all three operate in the unlicensed 2.4 GHz band, also known as ISM band, which has been key to the development of a competitive and innovative market for wireless embedded devices. But, as with any resource held in common, it is crucial that those technologies coexist peacefully to allow each user of the band to fulfill its communication goals. This has led to an increase in wireless devices intended for use in IEEE 802.11 wireless local area networks (WLANs) and wireless personal area networks (WPANs), both of which support operation in the crowded 2.4-GHz industrial, scientific and medical (ISM) band. Despite efforts made by standardization bodies to ensure smooth coexistence it may occur that communication technologies transmitting for instance at very different power levels interfere with each other. In particular, it has been pointed out that ZigBee could potentially experience interference from WiFi traffic given that while both protocols can transmit on the same channel, WiFi transmissions usually occur at much higher power level. In this work, we considered a heterogeneous network and analyzed the impact of coexistence between IEEE 802.15.4 and IEEE 802.11b. To evaluate the performance of this network, measurement and simulation study are conducted and developed in the QualNet Network simulator, version 5.0.Model is analyzed for different placement models or topologies such as Random. Grid & Uniform. Performance is analyzed on the basis of characteristics such as throughput, average jitter and average end to end delay. Here, the impact of varying different antenna gain & shadowing model for this

  20. performance characteristics of a cam turning attachment

    African Journals Online (AJOL)

    Dr Obe

    ABSTRACT. A modification of a cylindrical turning unit has been done to give a non- cylindrical turning attachment for production of irregular shapes, like cams on the lathe machine. To assess the performance of the attachment, cutting forces have been measured using a 'Sigma' Cutting Tool. Dynamometer. Furthermore ...

  1. Performance characteristics of a shower cooling tower

    International Nuclear Information System (INIS)

    Qi Xiaoni; Liu Zhenyan; Li Dandan

    2007-01-01

    This study was prompted by the need to design towers for applications in which, due to salt deposition on the packing and subsequent blockage, the use of tower packing is not practical. In contrast to conventional cooling towers, the cooling tower analyzed in this study is void of fill. By means of efficient atomization nozzles, a shower cooling tower (SCT) is possible to be applied in industry, which, in terms of water cooling, energy saving and equipment investing, is better than conventional packed cooling towers. However, no systematic thermodynamic numerical method could be found in the literature up to now. Based on the kinetic model and mass and heat transfer model, this paper has developed a one dimensional model for studying the motional process and evaporative cooling process occurring at the water droplet level in the SCT. The finite difference approach is used for three motional processes to obtain relative parameters in each different stage, and the possibility of the droplets being entrained outside the tower is fully analyzed. The accuracy of this model is checked by practical operational results from a full scale prototype in real conditions, and some exclusive factors that affect the cooling characteristics for the SCT are analyzed in detail. This study provides the theoretical foundation for practical application of the SCT in industry

  2. Some useful characteristics of performance models

    International Nuclear Information System (INIS)

    Worledge, D.H.

    1985-01-01

    This paper examines the demands placed upon models of human cognitive decision processes in application to Probabilistic Risk Assessment. Successful models, for this purpose, should, 1) be based on proven or plausible psychological knowledge, e.g., Rasmussen's mental schematic, 2) incorporate opportunities for slips, 3) take account of the recursive nature, in time, of corrections to mistaken actions, and 4) depend on the crew's predominant mental states that accompany such recursions. The latter is equivalent to an explicit coupling between input and output of Rasmussen's mental schematic. A family of such models is proposed with observable rate processes mediating the (conscious) mental states involved. It is expected that the cumulative probability distributions corresponding to the individual rate processes can be identified with probability-time correlations of the HCR Human Cognitive Reliability type discussed elsewhere in this session. The functional forms of the conditional rates are intuitively shown to have simple characteristics that lead to a strongly recursive stochastic process with significant predictive capability. Models of the type proposed have few parts and form a representation that is intentionally far short of a fully transparent exposition of the mental process in order to avoid making impossible demands on data

  3. Predicting Expressive Dynamics in Piano Performances using Neural Networks

    NARCIS (Netherlands)

    van Herwaarden, Sam; Grachten, Maarten; de Haas, W. Bas

    2014-01-01

    This paper presents a model for predicting expressive accentuation in piano performances with neural networks. Using Restricted Boltzmann Machines (RBMs), features are learned from performance data, after which these features are used to predict performed loudness. During feature learning, data

  4. Performance and carcass characteristics of Yankasa ram fed with ...

    African Journals Online (AJOL)

    Remember me ... and 50% maize and wheat offal mixture, were better when compared to the control (B0) and other test diet in terms of performance and carcass characteristics. ... Key words: Performance, carcass, biscuit waste, Yankasa ram.

  5. IMPACT OF SOCIAL NETWORK STRUCTURE ON EMPLOYEE PERFORMANCE: A COMPARATIVE STUDY

    OpenAIRE

    Claudio Lira Meirelles; Thais Cereda Ravasi; Fabio Teixeira Arten; João Paulo Lara Siqueira

    2013-01-01

    This research sought to understand the relationship between the position of the central actor and the performance of a network, checking the influence of the central actor's performance over other actors. Among the specific objectives, we sought to describe the transactional content, the nature of the connections and the structural characteristics of the network. Data were collected through a questionnaire and analyzed with the help of software UCINET 6.0 and Excel. The results suggest tha...

  6. Wireless Local Area Network Performance Inside Aircraft Passenger Cabins

    Science.gov (United States)

    Whetten, Frank L.; Soroker, Andrew; Whetten, Dennis A.; Whetten, Frank L.; Beggs, John H.

    2005-01-01

    An examination of IEEE 802.11 wireless network performance within an aircraft fuselage is performed. This examination measured the propagated RF power along the length of the fuselage, and the associated network performance: the link speed, total throughput, and packet losses and errors. A total of four airplanes: one single-aisle and three twin-aisle airplanes were tested with 802.11a, 802.11b, and 802.11g networks.

  7. Social Network Analysis and Qualitative Interviews for Assessing Geographic Characteristics of Tourism Business Networks.

    Directory of Open Access Journals (Sweden)

    Ilan Kelman

    Full Text Available This study integrates quantitative social network analysis (SNA and qualitative interviews for understanding tourism business links in isolated communities through analysing spatial characteristics. Two case studies are used, the Surselva-Gotthard region in the Swiss Alps and Longyearbyen in the Arctic archipelago of Svalbard, to test the spatial characteristics of physical proximity, isolation, and smallness for understanding tourism business links. In the larger Surselva-Gotthard region, we found a strong relationship between geographic separation of the three communities on compartmentalization of the collaboration network. A small set of businesses played a central role in steering collaborative decisions for this community, while a group of structurally 'peripheral' actors were less influential. By contrast, the business community in Svalbard showed compartmentalization that was independent of geographic distance between actors. Within towns of similar size and governance scale, Svalbard is more compartmentalized, and those compartments are not driven by geographic separation of the collaboration clusters. This compartmentalization in Svalbard was reflected in a lower density of formal business collaboration ties compared to the communities of the Alps. We infer that the difference is due to Svalbard having higher cultural diversity and population turnover than the Alps communities. We propose that integrating quantitative network analysis from simple surveys with qualitative interviews targeted from the network results is an efficient general approach to identify regionally specific constraints and opportunities for effective governance.

  8. Social Network Analysis and Qualitative Interviews for Assessing Geographic Characteristics of Tourism Business Networks.

    Science.gov (United States)

    Kelman, Ilan; Luthe, Tobias; Wyss, Romano; Tørnblad, Silje H; Evers, Yvette; Curran, Marina Martin; Williams, Richard J; Berlow, Eric L

    2016-01-01

    This study integrates quantitative social network analysis (SNA) and qualitative interviews for understanding tourism business links in isolated communities through analysing spatial characteristics. Two case studies are used, the Surselva-Gotthard region in the Swiss Alps and Longyearbyen in the Arctic archipelago of Svalbard, to test the spatial characteristics of physical proximity, isolation, and smallness for understanding tourism business links. In the larger Surselva-Gotthard region, we found a strong relationship between geographic separation of the three communities on compartmentalization of the collaboration network. A small set of businesses played a central role in steering collaborative decisions for this community, while a group of structurally 'peripheral' actors were less influential. By contrast, the business community in Svalbard showed compartmentalization that was independent of geographic distance between actors. Within towns of similar size and governance scale, Svalbard is more compartmentalized, and those compartments are not driven by geographic separation of the collaboration clusters. This compartmentalization in Svalbard was reflected in a lower density of formal business collaboration ties compared to the communities of the Alps. We infer that the difference is due to Svalbard having higher cultural diversity and population turnover than the Alps communities. We propose that integrating quantitative network analysis from simple surveys with qualitative interviews targeted from the network results is an efficient general approach to identify regionally specific constraints and opportunities for effective governance.

  9. Social Network Analysis and Qualitative Interviews for Assessing Geographic Characteristics of Tourism Business Networks

    Science.gov (United States)

    Luthe, Tobias; Wyss, Romano; Tørnblad, Silje H.; Evers, Yvette; Curran, Marina Martin; Williams, Richard J.; Berlow, Eric L.

    2016-01-01

    This study integrates quantitative social network analysis (SNA) and qualitative interviews for understanding tourism business links in isolated communities through analysing spatial characteristics. Two case studies are used, the Surselva-Gotthard region in the Swiss Alps and Longyearbyen in the Arctic archipelago of Svalbard, to test the spatial characteristics of physical proximity, isolation, and smallness for understanding tourism business links. In the larger Surselva-Gotthard region, we found a strong relationship between geographic separation of the three communities on compartmentalization of the collaboration network. A small set of businesses played a central role in steering collaborative decisions for this community, while a group of structurally ‘peripheral’ actors were less influential. By contrast, the business community in Svalbard showed compartmentalization that was independent of geographic distance between actors. Within towns of similar size and governance scale, Svalbard is more compartmentalized, and those compartments are not driven by geographic separation of the collaboration clusters. This compartmentalization in Svalbard was reflected in a lower density of formal business collaboration ties compared to the communities of the Alps. We infer that the difference is due to Svalbard having higher cultural diversity and population turnover than the Alps communities. We propose that integrating quantitative network analysis from simple surveys with qualitative interviews targeted from the network results is an efficient general approach to identify regionally specific constraints and opportunities for effective governance. PMID:27258007

  10. In-Network Performance of Handheld Mobile Terminals

    DEFF Research Database (Denmark)

    Nielsen, Jesper Ødum; Pedersen, Gert Frølund

    2006-01-01

    are compared with the equivalent performance obtained in a live GSM network using data from the Abis network interface. This method does not require altering of the handsets and the testing uses normal calls in the network. The investigation is based on measurements with four different commercially available...

  11. Performance characteristics for advanced control systems

    International Nuclear Information System (INIS)

    Kisner, R.A.

    1989-01-01

    A growing collection of control techniques is becoming available to the design engineer. This make selection of the most appropriate technique for a given application a difficult task. A systematic approach to evaluating alternative control schemes is needed. The approach discussed in this paper expands the traditional concepts of quantitative performance analysis to include other relevant factors such as robustness of the technique, resource requirements, and effects on operators and other personnel. This collection of factors, termed measures of utility, may be used as qualitative and quantitative means of evaluating and comparing properties of alternative control system designs. This paper, although not an in-depth study, serves to outline several measures of utility and suggests a general structure for control system development. This method of comparing the usefulness of alternative control system will prove valuable to the ORNL Advanced Controls Program (ACTO) for optimizing compatibility with actual systems and equipment

  12. Ethernet image communication performance in a multimodal PACS network

    International Nuclear Information System (INIS)

    Lou, S.L.; Valentino, D.J.; Chan, K.K.; Huang, H.K.

    1989-01-01

    The authors have evaluated the performance of an Ethernet network in a multimodal picture archiving and communications system (PACS) environment. The study included measurements between Sun workstations and PC- AT computers running communication software at the TCP level. First they initiated image transfers between two workstations, a server and a client. Next, they successively added clients to transfer images to the server and they measured degradation in network performance. Finally, they initiated image transfers between pairs of workstations and again measured performance degradation. The results of the authors' experiments indicate that Ethernet is suitable for image communication only in limited network situations. They discuss how to maximize network performance given these constraints

  13. [Social network analysis and high risk behavior characteristics of recreational drug users: a qualitative study].

    Science.gov (United States)

    Wu, Di; Wang, Zhenhong; Jiang, Zhenxia; Fu, Xiaojing; Li, Hui; Zhang, Dapeng; Liu, Hui; Hu, Yifei

    2014-11-01

    To understand the characteristics of recreational drug users' behaviors and social network, as well as their potential impact to the transmission of sexual transmitted infections (STI). Qualitative interview was used to collect information on rough estimation of population size and behavior change before and after recreational drug use. A total of 120 participants were recruited by convenient sampling from April to October, 2013 in a community of Qingdao city. Blood specimens were taken for HIV/syphilis serological testing and social network analysis was performed to understand the characteristics of their behavior and social network. All participants used methamphetamine and 103 of them showed social connection. The prevalence of syphilis and HIV were 24.2% (29/120) and 2.5% (3/120) respectively. The estimated size of recreational drug users was big with a wide diversity of occupations and age range, and males were more frequent than females. Drug use may affect condom use and frequent drug users showed symptom of psychosis and neuro-toxicities. The size of social network was 2.45 ± 1.63 in the past 6 months, which indicated an increasing trend of the sexual partner number and risky behaviors. Recreational drug use could increase the size of social network among sex partners, the frequency of risky sexual behaviors and syphilis prevalence, which indicate a high risk of HIV/STI among this population as well as a huge burden of disease prevention and control in the future.

  14. Deep Recurrent Convolutional Neural Network: Improving Performance For Speech Recognition

    OpenAIRE

    Zhang, Zewang; Sun, Zheng; Liu, Jiaqi; Chen, Jingwen; Huo, Zhao; Zhang, Xiao

    2016-01-01

    A deep learning approach has been widely applied in sequence modeling problems. In terms of automatic speech recognition (ASR), its performance has significantly been improved by increasing large speech corpus and deeper neural network. Especially, recurrent neural network and deep convolutional neural network have been applied in ASR successfully. Given the arising problem of training speed, we build a novel deep recurrent convolutional network for acoustic modeling and then apply deep resid...

  15. A general framework for performance guaranteed green data center networking

    OpenAIRE

    Wang, Ting; Xia, Yu; Muppala, Jogesh; Hamdi, Mounir; Foufou, Sebti

    2014-01-01

    From the perspective of resource allocation and routing, this paper aims to save as much energy as possible in data center networks. We present a general framework, based on the blocking island paradigm, to try to maximize the network power conservation and minimize sacrifices of network performance and reliability. The bandwidth allocation mechanism together with power-aware routing algorithm achieve a bandwidth guaranteed tighter network. Besides, our fast efficient heuristics for allocatin...

  16. MODEL OF EMERGENCY DEPARTMENT NURSE PERFORMANCE IMPROVEMENT BASED ON ASSOCIATION OF INDIVIDUAL CHARACTERISTIC, ORGANIZATION CHARACTERISTIC AND JOB CHARACTERISTIC

    Directory of Open Access Journals (Sweden)

    Maria Margaretha Bogar

    2017-04-01

    Full Text Available Introduction: Nursing care is integral part of health care and having important role in management of patient with emergency condition. The purpose of this research was to develop nurse performance improvement model based on individual, organization and job characteristics association in Emergency Department of RSUD dr TC Hillers Maumere. Method: This was an explanative survey by cross sectional approach held on July -August 2012. Respondents in this study were 22 nurses and 44 patients were obtained by purposive sampling technique. Data were analyzed by partial least square test and signi fi cant t value > 1.64 (alpha 10%. Result: Results showed that individual characteristic had effect on nurse performance (t = 7.59, organization characteristic had effect on nurse performance (t = 2.03 and job characteristic didn’t have effect on nurse performance (t = 0.88. Nurse performance had effect on patient satisfaction (t = 6.54 but nurse satisfaction didn’t have effect on nurse performance (t = 1.31, and nurse satisfaction didn’t have effect either on patient satisfaction (t = 0.94. Discussion: This research concluded that individual characteristics which in fl uence nurse performance in nursing care were ability and skill, experience, age, sex, attitude and motivation. Organization characteristic that influence nurse performance was reward while job characteristic that include job design and feedback didn’t influence nurse performance in nursing care. Nurse performance influenced patient satisfaction but nurse satisfaction didn’t influence patient satisfaction and nurse performance.

  17. Study on multiple-hops performance of MOOC sequences-based optical labels for OPS networks

    Science.gov (United States)

    Zhang, Chongfu; Qiu, Kun; Ma, Chunli

    2009-11-01

    In this paper, we utilize a new study method that is under independent case of multiple optical orthogonal codes to derive the probability function of MOOCS-OPS networks, discuss the performance characteristics for a variety of parameters, and compare some characteristics of the system employed by single optical orthogonal code or multiple optical orthogonal codes sequences-based optical labels. The performance of the system is also calculated, and our results verify that the method is effective. Additionally it is found that performance of MOOCS-OPS networks would, negatively, be worsened, compared with single optical orthogonal code-based optical label for optical packet switching (SOOC-OPS); however, MOOCS-OPS networks can greatly enlarge the scalability of optical packet switching networks.

  18. Characteristics of suicide hotspots on the Belgian railway network.

    Science.gov (United States)

    Debbaut, Kevin; Krysinska, Karolina; Andriessen, Karl

    2014-01-01

    In 2004, railway suicide accounted for 5.3% of all suicides in Belgium. In 2008, Infrabel (Manager of the Belgian Railway Infrastructure) introduced a railway suicide prevention programme, including identification of suicide hotspots, i.e., areas of the railway network with an elevated incidence of suicide. The study presents an analysis of 43 suicide hotspots based on Infrabel data collected during field visits and semi-structured interviews conducted in mental health facilities in the vicinity of the hotspots. Three major characteristics of the hotspots were accessibility, anonymity, and vicinity of a mental health institution. The interviews identified several risk and protective factors for railway suicide, including the training of staff, introduction of a suicide prevention policy, and the role of the media. In conclusion, a comprehensive railway suicide prevention programme should continuously safeguard and monitor hotspots, and should be embedded in a comprehensive suicide prevention programme in the community.

  19. Research about reactor operator's personality characteristics and performance

    International Nuclear Information System (INIS)

    Wei Li; He Xuhong; Zhao Bingquan

    2003-01-01

    To predict and evaluate the reactor operator's performance by personality characteristics is an important part of reactor operator safety assessment. Using related psychological theory combined with the Chinese operator's fact and considering the effect of environmental factors to personality analysis, paper does the research about the about the relationships between reactor operator's performance and personality characteristics, and offers the reference for operator's selection, using and performance in the future. (author)

  20. 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.

  1. Dynamic characteristics of a cyclic-periodic structure with a piezoelectric network

    Directory of Open Access Journals (Sweden)

    Li Lin

    2015-10-01

    Full Text Available This paper deals with a cyclic-periodic structure with a piezoelectric network. In such a system, there is not only mechanical connection but also electrical connection between adjacent periodic sectors. The objective is to learn whether the presence of a piezoelectric network would change the dynamic characteristics of the system. The background of the research is about vibration reduction of a bladed disk in an aero-engine, and the system is simulated by a lumped parameter model. The dynamic equations of the system are derived, and then the analytical solution corresponding to the eigenvalue problem is given. The vibration responses to single traveling wave excitations (EO excitations and multiple traveling wave excitations (NEO excitations are studied. The results show that the presence of a piezoelectric network would change the natural frequencies of the system compared with those of the system with the piezoelectric shunt circuit. The forced response is sensitive to the connection type and the elements of the network. An energy analysis of the electro-mechanical coupling system has been performed to understand its dynamic behavior, and the following conclusion is obtained: a vibration reduction to excitations whose primary harmonic component is not zero can be achieved by a parallel piezoelectric network, while a reduction to other excitations should be based on a series piezoelectric network.

  2. Identification and adaptive neural network control of a DC motor system with dead-zone characteristics.

    Science.gov (United States)

    Peng, Jinzhu; Dubay, Rickey

    2011-10-01

    In this paper, an adaptive control approach based on the neural networks is presented to control a DC motor system with dead-zone characteristics (DZC), where two neural networks are proposed to formulate the traditional identification and control approaches. First, a Wiener-type neural network (WNN) is proposed to identify the motor DZC, which formulates the Wiener model with a linear dynamic block in cascade with a nonlinear static gain. Second, a feedforward neural network is proposed to formulate the traditional PID controller, termed as PID-type neural network (PIDNN), which is then used to control and compensate for the DZC. In this way, the DC motor system with DZC is identified by the WNN identifier, which provides model information to the PIDNN controller in order to make it adaptive. Back-propagation algorithms are used to train both neural networks. Also, stability and convergence analysis are conducted using the Lyapunov theorem. Finally, experiments on the DC motor system demonstrated accurate identification and good compensation for dead-zone with improved control performance over the conventional PID control. Copyright © 2011 ISA. Published by Elsevier Ltd. All rights reserved.

  3. Performance evaluation of packet video transfer over local area networks

    OpenAIRE

    Lu, Jie

    1993-01-01

    This research investigates the implementation and performance of packet video transfer over local area networks. A network architecture is defined for packet video such that most of the processing is performed by the higher layers of the Open Systems Interconnection (OSI) reference model, while the lower layers provide real-time services. Implementation methods are discussed for coding schemes, including data compression, the network interface unit, and the underlying local are...

  4. User-Location Aware Downlink Performance Analysis of LTE Networks

    OpenAIRE

    Olaifa, John Olorunfemi

    2016-01-01

    In order to evaluate the performance of Long Term Evolution (LTE) networks, system-level simulation with detailed focus on network related effects such as mobility, scheduling and interference management must be emphasized. Existing studies evaluate user throughput and dimension LTE networks usually assuming uniform distribution of users within the cell. These studies report average user throughputs over the cell and the 5th percentile throughputs as estimates of the performance of the users ...

  5. Application of Bayesian Networks for Estimation of Individual Psychological Characteristics

    KAUST Repository

    Litvinenko, Alexander

    2017-07-19

    In this paper we apply Bayesian networks for developing more accurate final overall estimations of psychological characteristics of an individual, based on psychological test results. Psychological tests which identify how much an individual possesses a certain factor are very popular and quite common in the modern world. We call this value for a given factor -- the final overall estimation. Examples of factors could be stress resistance, the readiness to take a risk, the ability to concentrate on certain complicated work and many others. An accurate qualitative and comprehensive assessment of human potential is one of the most important challenges in any company or collective. The most common way of studying psychological characteristics of each single person is testing. Psychologists and sociologists are constantly working on improvement of the quality of their tests. Despite serious work, done by psychologists, the questions in tests often do not produce enough feedback due to the use of relatively poor estimation systems. The overall estimation is usually based on personal experiences and the subjective perception of a psychologist or a group of psychologists about the investigated psychological personality factors.

  6. Application of Bayesian Networks for Estimation of Individual Psychological Characteristics

    KAUST Repository

    Litvinenko, Alexander; Litvinenko, Natalya

    2017-01-01

    In this paper we apply Bayesian networks for developing more accurate final overall estimations of psychological characteristics of an individual, based on psychological test results. Psychological tests which identify how much an individual possesses a certain factor are very popular and quite common in the modern world. We call this value for a given factor -- the final overall estimation. Examples of factors could be stress resistance, the readiness to take a risk, the ability to concentrate on certain complicated work and many others. An accurate qualitative and comprehensive assessment of human potential is one of the most important challenges in any company or collective. The most common way of studying psychological characteristics of each single person is testing. Psychologists and sociologists are constantly working on improvement of the quality of their tests. Despite serious work, done by psychologists, the questions in tests often do not produce enough feedback due to the use of relatively poor estimation systems. The overall estimation is usually based on personal experiences and the subjective perception of a psychologist or a group of psychologists about the investigated psychological personality factors.

  7. Topology influences performance in the associative memory neural networks

    International Nuclear Information System (INIS)

    Lu Jianquan; He Juan; Cao Jinde; Gao Zhiqiang

    2006-01-01

    To explore how topology affects performance within Hopfield-type associative memory neural networks (AMNNs), we studied the computational performance of the neural networks with regular lattice, random, small-world, and scale-free structures. In this Letter, we found that the memory performance of neural networks obtained through asynchronous updating from 'larger' nodes to 'smaller' nodes are better than asynchronous updating in random order, especially for the scale-free topology. The computational performance of associative memory neural networks linked by the above-mentioned network topologies with the same amounts of nodes (neurons) and edges (synapses) were studied respectively. Along with topologies becoming more random and less locally disordered, we will see that the performance of associative memory neural network is quite improved. By comparing, we show that the regular lattice and random network form two extremes in terms of patterns stability and retrievability. For a network, its patterns stability and retrievability can be largely enhanced by adding a random component or some shortcuts to its structured component. According to the conclusions of this Letter, we can design the associative memory neural networks with high performance and minimal interconnect requirements

  8. Topological Effects and Performance Optimization in Transportation Continuous Network Design

    Directory of Open Access Journals (Sweden)

    Jianjun Wu

    2014-01-01

    Full Text Available Because of the limitation of budget, in the planning of road works, increased efforts should be made on links that are more critical to the whole traffic system. Therefore, it would be helpful to model and evaluate the vulnerability and reliability of the transportation network when the network design is processing. This paper proposes a bilevel transportation network design model, in which the upper level is to minimize the performance of the network under the given budgets, while the lower level is a typical user equilibrium assignment problem. A new solution approach based on particle swarm optimization (PSO method is presented. The topological effects on the performance of transportation networks are studied with the consideration of three typical networks, regular lattice, random graph, and small-world network. Numerical examples and simulations are presented to demonstrate the proposed model.

  9. Ensemble of classifiers based network intrusion detection system performance bound

    CSIR Research Space (South Africa)

    Mkuzangwe, Nenekazi NP

    2017-11-01

    Full Text Available This paper provides a performance bound of a network intrusion detection system (NIDS) that uses an ensemble of classifiers. Currently researchers rely on implementing the ensemble of classifiers based NIDS before they can determine the performance...

  10. 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.

  11. Network performance of a wireless sensor network for temperature monitoring in vineyards

    DEFF Research Database (Denmark)

    Liscano, Ramiro; Jacoub, John Khalil; Dersingh, Anand

    2011-01-01

    Wireless sensor networks (WSNs) are an emerging technology which can be used for outdoor environmental monitoring. This paper presents challenges that arose from the development and deployment of a WSN for environmental monitoring as well as network performance analysis of this network. Different...... components in our sensor network architecture are presented like the physical nodes, the sensor node code, and two messaging protocols; one for collecting sensor and network values and the other for sensor node commands. An information model for sensor nodes to support plug-and-play capabilities in sensor...... networks is also presented....

  12. Network Characteristics and Dynamics: Reciprocity, Competition and Information Dissemination

    Science.gov (United States)

    2015-09-01

    discrete entities or components of a system and edges represent dyadic relations be- tween components. Prominent examples are online social networks such as... community , and considerable work has been devoted to their study. One line of study focuses on the structural properties of networks themselves. Ex...networks [73, 74, 68, 76, 70, 80], communication networks [52], product co-purchasing networks [52], web graphs [52], Wikipedias [1], software call graphs

  13. Force10 networks performance in world's first transcontinental 10 gigabit ethernet network verified by Ixia

    CERN Multimedia

    2003-01-01

    Force10 Networks, Inc., today announced that the performance of the Force10 E-Series switch/routers deployed in a transcontinental network has been verified as line-rate 10 GE throughput by Ixia, a leading provider of high-speed, network performance and conformance analysis systems. The network, the world's first transcontinental 10 GE wide area network, consists of a SURFnet OC-192 lambda between Geneva and the StarLight facility in Chicago via Amsterdam and another OC-192 lambda between this same facility in Chicago and Carleton University in Ottawa, Canada provided by CANARIE and ORANO (1/2 page).

  14. Job Characteristics, Work Involvement, and Job Performance of Public Servants

    Science.gov (United States)

    Johari, Johanim; Yahya, Khulida Kirana

    2016-01-01

    Purpose: The primary purpose of this study is to assess the predicting role of job characteristics on job performance. Dimensions in the job characteristics construct are skill variety, task identity, task significance, autonomy and feedback. Further, work involvement is tested as a mediator in the hypothesized link. Design/methodology/approach: A…

  15. Performance Evaluation of Coded Meshed Networks

    DEFF Research Database (Denmark)

    Krigslund, Jeppe; Hansen, Jonas; Pedersen, Morten Videbæk

    2013-01-01

    of the former to enhance the gains of the latter. We first motivate our work through measurements in WiFi mesh networks. Later, we compare state-of-the-art approaches, e.g., COPE, RLNC, to CORE. Our measurements show the higher reliability and throughput of CORE over other schemes, especially, for asymmetric...

  16. Envisioning Networked Urban Mobilities : Art, Performances, Impacts

    NARCIS (Netherlands)

    Kjaerulf, Aslak Aamot; Kesselring, Sven; Peters, Peter; Hannam, Kevin

    2017-01-01

    Envisioning Networked Urban Mobilities brings together scientific reflections on the relations of art and urban mobilities and artistic research on the topic. The editors open the book by setting out the concept grounded in the exhibition curated by Aslak Aamot Kjærulff and refers to earlier work on

  17. Analysis of characteristic performance curves in radiodiagnosis by an observer

    International Nuclear Information System (INIS)

    Kossovoj, A.L.

    1988-01-01

    Methods and ways of construction of performance characteristic curves (PX-curves) in roentgenology, their qualitative and quantitative estimation are described. Estimation of PX curves application for analysis of scintigraphic and sonographic images is presented

  18. Evaluation of the productive performance characteristics of red ...

    African Journals Online (AJOL)

    Evaluation of the productive performance characteristics of red tilapia ( Oreochromis sp.) injected with shark DNA into skeletal muscles and maintained diets containing different levels of probiotic and amino yeast.

  19. Wireless ad hoc and sensor networks management, performance, and applications

    CERN Document Server

    He, Jing

    2013-01-01

    Although wireless sensor networks (WSNs) have been employed across a wide range of applications, there are very few books that emphasize the algorithm description, performance analysis, and applications of network management techniques in WSNs. Filling this need, Wireless Ad Hoc and Sensor Networks: Management, Performance, and Applications summarizes not only traditional and classical network management techniques, but also state-of-the-art techniques in this area. The articles presented are expository, but scholarly in nature, including the appropriate history background, a review of current

  20. Performers and performance : how to investigate the contribution of the operational network to operational performance

    NARCIS (Netherlands)

    Wijngaard, J.; Vries, J. de; Nauta, A.

    2006-01-01

    Purpose This paper seeks to explore the question of how to investigate the contribution of the operational network (comprising sales service, logistics, planning, production, etc.) to operational performance. In doing so, the paper aims to link concepts from organisational and social psychology to

  1. Performers and performance : How to investigate the contribution of the operational network to operational performance

    NARCIS (Netherlands)

    Wijngaard, J.; de Vries, J.; Nauta, Aukje

    2006-01-01

    Purpose - This paper seeks to explore the question of how to investigate the contribution of the operational network (comprising sales service, logistics, planning, production, etc.) to operational performance. In doing so, the paper aims to link concepts from organisational and social psychology to

  2. Performance testing framework for smart grid communication network

    International Nuclear Information System (INIS)

    Quang, D N; See, O H; Chee, L L; Xuen, C Y; Karuppiah, S

    2013-01-01

    Smart grid communication network is comprised of different communication mediums and technologies. Performance evaluation is one of the main concerns in smart grid communication system. In any smart grid communication implementation, to determine the performance factor of the network, a testing of an end-to-end process flow is required. Therefore, an effective and coordinated testing procedure plays a crucial role in evaluating the performance of smart grid communications. In this paper, a testing framework is proposed as a guideline to analyze and assess the performance of smart grid communication network.

  3. Topology design and performance analysis of an integrated communication network

    Science.gov (United States)

    Li, V. O. K.; Lam, Y. F.; Hou, T. C.; Yuen, J. H.

    1985-01-01

    A research study on the topology design and performance analysis for the Space Station Information System (SSIS) network is conducted. It is begun with a survey of existing research efforts in network topology design. Then a new approach for topology design is presented. It uses an efficient algorithm to generate candidate network designs (consisting of subsets of the set of all network components) in increasing order of their total costs, and checks each design to see if it forms an acceptable network. This technique gives the true cost-optimal network, and is particularly useful when the network has many constraints and not too many components. The algorithm for generating subsets is described in detail, and various aspects of the overall design procedure are discussed. Two more efficient versions of this algorithm (applicable in specific situations) are also given. Next, two important aspects of network performance analysis: network reliability and message delays are discussed. A new model is introduced to study the reliability of a network with dependent failures. For message delays, a collection of formulas from existing research results is given to compute or estimate the delays of messages in a communication network without making the independence assumption. The design algorithm coded in PASCAL is included as an appendix.

  4. The Influence of Top Management Team Characteristics on BPD Performance

    Directory of Open Access Journals (Sweden)

    Joy Elly Tulung

    2015-12-01

    Full Text Available Based on ”upper echelons theory”, this paper investigates the relation between top management team composition and BPD performance. For top management team characteristics, we employ age, level of education, background of education, gender, and functional background, while for measured the BPD performance we employ return on asset (ROA, return on equity (ROE, capital adequacy ratio (CAR, net interest margin (NIM, loan to deposit ratio (LDR, non-performing loan (NPL and operation expenses to operation income (BOPO. The results show that all characteristics have positive significant influences on BPD performance.

  5. Applying neural networks to optimize instrumentation performance

    Energy Technology Data Exchange (ETDEWEB)

    Start, S.E.; Peters, G.G.

    1995-06-01

    Well calibrated instrumentation is essential in providing meaningful information about the status of a plant. Signals from plant instrumentation frequently have inherent non-linearities, may be affected by environmental conditions and can therefore cause calibration difficulties for the people who maintain them. Two neural network approaches are described in this paper for improving the accuracy of a non-linear, temperature sensitive level probe ised in Expermental Breeder Reactor II (EBR-II) that was difficult to calibrate.

  6. Applying neural networks to optimize instrumentation performance

    International Nuclear Information System (INIS)

    Start, S.E.; Peters, G.G.

    1995-01-01

    Well calibrated instrumentation is essential in providing meaningful information about the status of a plant. Signals from plant instrumentation frequently have inherent non-linearities, may be affected by environmental conditions and can therefore cause calibration difficulties for the people who maintain them. Two neural network approaches are described in this paper for improving the accuracy of a non-linear, temperature sensitive level probe ised in Expermental Breeder Reactor II (EBR-II) that was difficult to calibrate

  7. Assessing the efficiency of different CSO positions based on network graph characteristics.

    Science.gov (United States)

    Sitzenfrei, R; Urich, C; Möderl, M; Rauch, W

    2013-01-01

    The technical design of urban drainage systems comprises two major aspects: first, the spatial layout of the sewer system and second, the pipe-sizing process. Usually, engineers determine the spatial layout of the sewer network manually, taking into account physical features and future planning scenarios. Before the pipe-sizing process starts, it is important to determine locations of possible weirs and combined sewer overflows (CSOs) based on, e.g. distance to receiving water bodies or to a wastewater treatment plant and available space for storage units. However, positions of CSOs are also determined by topological characteristics of the sewer networks. In order to better understand the impact of placement choices for CSOs and storage units in new systems, this work aims to determine case unspecific, general rules. Therefore, based on numerous, stochastically generated virtual alpine sewer systems of different sizes it is investigated how choices for placement of CSOs and storage units have an impact on the pipe-sizing process (hence, also on investment costs) and on technical performance (CSO efficiency and flooding). To describe the impact of the topological positions of these elements in the sewer networks, graph characteristics are used. With an evaluation of 2,000 different alpine combined sewer systems, it was found that, as expected, with CSOs at more downstream positions in the network, greater construction costs and better performance regarding CSO efficiency result. At a specific point (i.e. topological network position), no significant difference (further increase) in construction costs can be identified. Contrarily, the flooding efficiency increases with more upstream positions of the CSOs. Therefore, CSO and flooding efficiency are in a trade-off conflict and a compromise is required.

  8. Switching performance of OBS network model under prefetched real traffic

    Science.gov (United States)

    Huang, Zhenhua; Xu, Du; Lei, Wen

    2005-11-01

    Optical Burst Switching (OBS) [1] is now widely considered as an efficient switching technique in building the next generation optical Internet .So it's very important to precisely evaluate the performance of the OBS network model. The performance of the OBS network model is variable in different condition, but the most important thing is that how it works under real traffic load. In the traditional simulation models, uniform traffics are usually generated by simulation software to imitate the data source of the edge node in the OBS network model, and through which the performance of the OBS network is evaluated. Unfortunately, without being simulated by real traffic, the traditional simulation models have several problems and their results are doubtable. To deal with this problem, we present a new simulation model for analysis and performance evaluation of the OBS network, which uses prefetched IP traffic to be data source of the OBS network model. The prefetched IP traffic can be considered as real IP source of the OBS edge node and the OBS network model has the same clock rate with a real OBS system. So it's easy to conclude that this model is closer to the real OBS system than the traditional ones. The simulation results also indicate that this model is more accurate to evaluate the performance of the OBS network system and the results of this model are closer to the actual situation.

  9. Structure of Small World Innovation Network and Learning Performance

    Directory of Open Access Journals (Sweden)

    Shuang Song

    2014-01-01

    Full Text Available This paper examines the differences of learning performance of 5 MNCs (multinational corporations that filed the largest number of patents in China. We establish the innovation network with the patent coauthorship data by these 5 MNCs and classify the networks by the tail of distribution curve of connections. To make a comparison of the learning performance of these 5 MNCs with differing network structures, we develop an organization learning model by regarding the reality as having m dimensions, which denotes the heterogeneous knowledge about the reality. We further set n innovative individuals that are mutually interactive and own unique knowledge about the reality. A longer (shorter distance between the knowledge of the individual and the reality denotes a lower (higher knowledge level of that individual. Individuals interact with and learn from each other within the small-world network. By making 1,000 numerical simulations and averaging the simulated results, we find that the differing structure of the small-world network leads to the differences of learning performance between these 5 MNCs. The network monopolization negatively impacts and network connectivity positively impacts learning performance. Policy implications in the conclusion section suggest that to improve firm learning performance, it is necessary to establish a flat and connective network.

  10. Improved PPP Ambiguity Resolution Considering the Stochastic Characteristics of Atmospheric Corrections from Regional Networks

    Science.gov (United States)

    Li, Yihe; Li, Bofeng; Gao, Yang

    2015-01-01

    With the increased availability of regional reference networks, Precise Point Positioning (PPP) can achieve fast ambiguity resolution (AR) and precise positioning by assimilating the satellite fractional cycle biases (FCBs) and atmospheric corrections derived from these networks. In such processing, the atmospheric corrections are usually treated as deterministic quantities. This is however unrealistic since the estimated atmospheric corrections obtained from the network data are random and furthermore the interpolated corrections diverge from the realistic corrections. This paper is dedicated to the stochastic modelling of atmospheric corrections and analyzing their effects on the PPP AR efficiency. The random errors of the interpolated corrections are processed as two components: one is from the random errors of estimated corrections at reference stations, while the other arises from the atmospheric delay discrepancies between reference stations and users. The interpolated atmospheric corrections are then applied by users as pseudo-observations with the estimated stochastic model. Two data sets are processed to assess the performance of interpolated corrections with the estimated stochastic models. The results show that when the stochastic characteristics of interpolated corrections are properly taken into account, the successful fix rate reaches 93.3% within 5 min for a medium inter-station distance network and 80.6% within 10 min for a long inter-station distance network. PMID:26633400

  11. Comparative indicators for cancer network management in England: Availability, characteristics and presentation

    Directory of Open Access Journals (Sweden)

    Coleman Michel P

    2008-02-01

    Full Text Available Abstract Background In 2000, the national cancer plan for England created 34 cancer networks, new organisational structures to coordinate services across populations varying between a half and three million people. We investigated the availability of data sets reflecting measures of structure, process and outcome that could be used to support network management. Methods We investigated the properties of national data sets relating to four common cancers – breast, colorectal, lung and prostate. We reviewed the availability and completeness of these data sets, identified leading items within each set and put them into tables of the 34 cancer networks. We also investigated methods of presentation. Results The Acute Hospitals Portfolio and the Cancer Standards Peer Review recorded structural characteristics at hospital and cancer service level. Process measures included Hospital Episode Statistics, recording admissions, and Hospital Waiting-List data. Patient outcome measures included the National Survey of Patient Satisfaction for cancer, and cancer survival, drawn from cancer registration. Data were drawn together to provide an exemplar indicator set a single network, and methods of graphical presentation were considered. Conclusion While not as yet used together in practice, comparative indicators are available within the National Health Service in England for use in performance assessment by cancer networks.

  12. The enhancing impact of friendship networks on sales managers' performance

    OpenAIRE

    Claro, Danny Pimentel; Laban Neto, Silvio Abrahão; Claro, Priscila Borin de Oliveira

    2013-01-01

    This paper examines how relationships with friends moderate the impact of professional networks on sales performance. Based on a sample of 204 sales managers in a professional service company, this study presents evidence that friendship networks amplify the effect of sales forces’ professional networks on new product sales as well as on prospecting and converting new deals. Our results offer important insights into the socio-cognitive perspective of sales management literature and suggest th...

  13. High Performance Networks From Supercomputing to Cloud Computing

    CERN Document Server

    Abts, Dennis

    2011-01-01

    Datacenter networks provide the communication substrate for large parallel computer systems that form the ecosystem for high performance computing (HPC) systems and modern Internet applications. The design of new datacenter networks is motivated by an array of applications ranging from communication intensive climatology, complex material simulations and molecular dynamics to such Internet applications as Web search, language translation, collaborative Internet applications, streaming video and voice-over-IP. For both Supercomputing and Cloud Computing the network enables distributed applicati

  14. Social networks and performance in distributed learning communities

    OpenAIRE

    Cadima, Rita; Ojeda Rodríguez, Jordi; Monguet Fierro, José María

    2012-01-01

    Social networks play an essential role in learning environments as a key channel for knowledge sharing and students' support. In distributed learning communities, knowledge sharing does not occur as spontaneously as when a working group shares the same physical space; knowledge sharing depends even more on student informal connections. In this study we analyse two distributed learning communities' social networks in order to understand how characteristics of the social structure can enhance s...

  15. Academic Performance and the Use of Social Networks

    Directory of Open Access Journals (Sweden)

    Jéssica Ribeiro Rangel

    2016-08-01

    Full Text Available This study aimed to investigate whether the use of social networks influences on the academic performance of students in the undergraduate program in accounting. Data were collected from 322 students of the course of a federal University of the State of Minas Gerais, Brazil. The regression results show that the variables "gender", "motivation" and "classification in the University entrance examination" are significant in explaining students' academic performance measured by the Grade Point Average (GPA. The results show that the performance of male students is lower than that of female students at the level of 5%. Also was identified that the greater the student's motivation level, the greater your academic performance (at the level of 1 percent. Finally, it was observed that the best ranked students in the University entrance examination, the higher their academic performance. However, none of the variables relating to the use of social networks ("familiarity with technological resources", "hours", "Internet hours on social networks" and "use of social networks to study" presented relation with academic performance. In other words, these results show that the use of social networks does not have positive or negative impacts directly on academic performance. We can conclude for the sample analyzed, that use of social networks during the academic period does not influence significantly the performance of the students. However, you can verify that the motivation is directly related to the academic performance of the Accounting student with regard to perception of motivation, to familiarity with technological resources and the use of applications.

  16. IT Performance Dashboard: Network/Security Dashboard

    Data.gov (United States)

    Department of Veterans Affairs — The IT Performance Dashboard is a trusted source for IT performance information across VA. This is available only on the VA intranet. The dashboard is a collection...

  17. A Mathematical Model to Improve the Performance of Logistics Network

    Directory of Open Access Journals (Sweden)

    Muhammad Izman Herdiansyah

    2012-01-01

    Full Text Available The role of logistics nowadays is expanding from just providing transportation and warehousing to offering total integrated logistics. To remain competitive in the global market environment, business enterprises need to improve their logistics operations performance. The improvement will be achieved when we can provide a comprehensive analysis and optimize its network performances. In this paper, a mixed integer linier model for optimizing logistics network performance is developed. It provides a single-product multi-period multi-facilities model, as well as the multi-product concept. The problem is modeled in form of a network flow problem with the main objective to minimize total logistics cost. The problem can be solved using commercial linear programming package like CPLEX or LINDO. Even in small case, the solver in Excel may also be used to solve such model.Keywords: logistics network, integrated model, mathematical programming, network optimization

  18. Hospital ownership, decisions on supervisory board characteristics, and financial performance.

    Science.gov (United States)

    Kuntz, Ludwig; Pulm, Jannis; Wittland, Michael

    2016-01-01

    Dynamic and complex transformations in the hospital market increase the relevance of good corporate governance. However, hospital performance and the characteristics of supervisory boards differ depending on ownership. The question therefore arises whether hospital owners can influence performance by addressing supervisory board characteristics. The objective of this study is to explain differences in the financial performance of hospitals with regard to ownership by studying the size and composition of supervisory boards. The AMADEUS database was used to collect information on hospital financial performance in 2009 and 2010. Business and quality reports, hospital websites, and data from health insurer were used to obtain information on hospital and board characteristics. The resulting sample consisted of 175 German hospital corporations. We utilized ANOVA and regression analysis to test a mediation hypothesis that investigated whether decisions regarding board size and composition were associated with financial performance and could explain performance differences. Financial performance and board size and composition depend on ownership. An increase in board size and greater politician participation were negatively associated with all five tested measures of financial performance. Furthermore, an increase in physician participation was positively associated with one dimension of financial performance, whereas one negative relationship was identified for nurse and economist participation. For clerics, no associations were found. Decisions concerning board size and composition are important as they relate to hospital financial performance. We contribute to existing research by showing that, in addition to board size and physician participation, the participation of other professionals can also influence financial performance.

  19. Towards a Social Networks Model for Online Learning & Performance

    Science.gov (United States)

    Chung, Kon Shing Kenneth; Paredes, Walter Christian

    2015-01-01

    In this study, we develop a theoretical model to investigate the association between social network properties, "content richness" (CR) in academic learning discourse, and performance. CR is the extent to which one contributes content that is meaningful, insightful and constructive to aid learning and by social network properties we…

  20. 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...

  1. Aggregate packing characteristics of good and poor performing asphalt mixes

    CSIR Research Space (South Africa)

    Denneman, E

    2007-07-01

    Full Text Available The aggregate structure of the compacted mix is a determining factor for the performance of Hot-Mix Asphalt (HMA). In this paper, the grading characteristics of good and poor performing HMA mixes are explored using the concepts of the Bailey method...

  2. Relationship Between Job Characteristics And Job Performance Of ...

    African Journals Online (AJOL)

    The agricultural extension agent is a key stakeholder in extension systems. The nature of their work is so important that it has overriding effect on their job performance. This study investigates the relationship between job characteristics and job performance of agricultural extension agents in Imo and Rivers States, Nigeria.

  3. Influence of course characteristics, student characteristics, and behavior in learning management systems on student performance

    OpenAIRE

    Conijn, Rianne; Kleingeld, Ad; Matzat, Uwe; Snijders, Chris; van Zaanen, Menno

    2016-01-01

    The use of learning management systems (LMS) in education make it possible to track students’ online behavior. This data can be used for educational data mining and learning analytics, for example, by predicting student performance. Although LMS data might contain useful predictors, course characteristics and student characteristics have shown to influence student performance as well. However, these different sets of features are rarely combined or compared. Therefore, in the current study we...

  4. Nonlinear Performance Characteristics of Flux-Switching PM Motors

    Directory of Open Access Journals (Sweden)

    E. Ilhan

    2013-01-01

    Full Text Available Nonlinear performance characteristics of 3-phase flux-switching permanent magnet motors (FSPM are overviewed. These machines show advantages of a robust rotor structure and a high energy density. Research on the FSPM is predominated by topics such as modeling and machine comparison, with little emphasis given on its performance and limits. Performance characteristics include phase flux linkage, phase torque, and phase inductance. In the paper, this analysis is done by a cross-correlation of rotor position and armature current. Due to the high amount of processed data, which cannot be handled analytically within an acceptable time period, a multistatic 2D finite element model (FEM is used. For generalization, the most commonly discussed FSPM topology, 12/10 FSPM, is chosen. Limitations on the motor performance due to the saturation are discussed on each characteristic. Additionally, a focused overview is given on energy conversion loops and dq-axes identification for the FSPM.

  5. Covariance of engineering management characteristics with engineering employee performance

    Science.gov (United States)

    Hesketh, Andrew Arthur

    1998-12-01

    As business in the 1990's grapples with the impact of continuous improvement and quality to meet market demands, there is an increased need to improve the leadership capabilities of our managers. Engineers have indicated desire for certain managerial characteristics in their leadership but there have been no studies completed that approached the problem of determining what managerial characteristics were best at improving employee performance. This study addressed the idea of identifying certain managerial characteristics that enhance employee performance. In the early 1990's, McDonnell Douglas Aerospace in St. Louis used a forced distribution system and allocated 35% of its employees into a "exceeds expectations" category and 60% into a "meets expectations" category. A twenty-question 5 point Likert scale survey on managerial capabilities was administered to a sample engineering population that also obtained their "expectations" category. A single factor ANOVA on the survey results determined a statistical difference between the "exceeds" and "meets" employees with four of the managerial capability questions. The "exceeds expectations" employee indicated that supervision did a better job of supporting subordinate development, clearly communicating performance expectations, and providing timely performance feedback when compared to the "meets expectations" employee. The "meets expectations" employee felt that their opinions, when different from their supervisor's, were more often ignored when compared to the "exceeds expectations" employee. These four questions relate to two specific managerial characteristics, "gaining (informal) authority and support" or "control" characteristic and "providing assistance and guidance" or "command" characteristic, that can be emphasized in managerial training programs.

  6. Performance of the TRISTAN computer control network

    International Nuclear Information System (INIS)

    Koiso, H.; Abe, K.; Akiyama, A.; Katoh, T.; Kikutani, E.; Kurihara, N.; Kurokawa, S.; Oide, K.; Shinomoto, M.

    1985-01-01

    An N-to-N token ring network of twenty-four minicomputers controls the TRISTAN accelerator complex. The computers are linked by optical fiber cables with 10 Mbps transmission speed. The software system is based on the NODAL, a multi-computer interpreter language developed at CERN SPS. Typical messages exchanged between computers are NODAL programs and NODAL variables transmitted by the EXEC and the REMIT commands. These messages are exchanged as a cluster of packets whose maximum size is 512 bytes. At present, eleven minicomputers are connected to the network and the total length of the ring is 1.5 km. In this condition, the maximum attainable throughput is 980 kbytes/s. The response of a pair of an EXEC and a REMIT transactions which transmit a NODAL array A and one line of program 'REMIT A' and immediately remit the A is measured to be 95+0.039/chi/ ms, where /chi/ is the array size in byte. In ordinary accelerator operations, the maximum channel utilization is 2%, the average packet length is 96 bytes and the transmission rate is 10 kbytes/s

  7. Social networks : Effects on Identification, Performance and Satisfaction Effects on identification, performance and satisfaction

    NARCIS (Netherlands)

    Stormbroek-Burgers, van R.G.B.M.; Montfort, van K.; Sluis, van der E.C. (Lidewey)

    2011-01-01

    This study contributes to research on the impact of social networks on organizational outcomes in the context of the increasing number of professionals in the Netherlands. The aim of this study was to get insight into the characteristics of professionals’ social networks and to examine the effect of

  8. Network Characteristics, Perceived Social Support, and Psychological Adjustment in Mothers of Children with Autism Spectrum Disorder

    Science.gov (United States)

    Benson, Paul R.

    2012-01-01

    This study examined the characteristics of the support networks of 106 mothers of children with ASD and their relationship to perceived social support, depressed mood, and subjective well-being. Using structural equation modeling, two competing sets of hypotheses were assessed: (1) that network characteristics would impact psychological adjustment…

  9. Personal networks in Saudi Arabia : The role of ascribed and achieved characteristics

    NARCIS (Netherlands)

    van Tubergen, Frank|info:eu-repo/dai/nl/271429534; Ali Al-Modaf, Obaid; Almosaed, Nora F.; Said Al-Ghamdi, Mohammed Ben

    2016-01-01

    This study examines how ascribed characteristics (gender and nationality) and achieved characteristics (SES) are related to the extensity and occupational resources of personal networks in Saudi Arabia. Using large-scale survey data from Jeddah, results show that networks of women are smaller and

  10. The performance analysis of linux networking - packet receiving

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Wenji; Crawford, Matt; Bowden, Mark; /Fermilab

    2006-11-01

    The computing models for High-Energy Physics experiments are becoming ever more globally distributed and grid-based, both for technical reasons (e.g., to place computational and data resources near each other and the demand) and for strategic reasons (e.g., to leverage equipment investments). To support such computing models, the network and end systems, computing and storage, face unprecedented challenges. One of the biggest challenges is to transfer scientific data sets--now in the multi-petabyte (10{sup 15} bytes) range and expected to grow to exabytes within a decade--reliably and efficiently among facilities and computation centers scattered around the world. Both the network and end systems should be able to provide the capabilities to support high bandwidth, sustained, end-to-end data transmission. Recent trends in technology are showing that although the raw transmission speeds used in networks are increasing rapidly, the rate of advancement of microprocessor technology has slowed down. Therefore, network protocol-processing overheads have risen sharply in comparison with the time spent in packet transmission, resulting in degraded throughput for networked applications. More and more, it is the network end system, instead of the network, that is responsible for degraded performance of network applications. In this paper, the Linux system's packet receive process is studied from NIC to application. We develop a mathematical model to characterize the Linux packet receiving process. Key factors that affect Linux systems network performance are analyzed.

  11. Multicast Performance Analysis for High-Speed Torus Networks

    National Research Council Canada - National Science Library

    Oral, S; George, A

    2002-01-01

    ... for unicast-based and path-based multicast communication on high-speed torus networks. Software-based multicast performance results of selected algorithms on a 16-node Scalable Coherent Interface (SCI) torus are given...

  12. Safety performance indicators for the road network.

    NARCIS (Netherlands)

    Weijermars, W. Gitelman, V. Papadimitriou, E. Lima De & Azevedo, C.

    2010-01-01

    Within the 6th FP European project SafetyNet, a team has worked on the development of Safety Performance Indicators (SPIs) on seven road safety related areas. These SPIs reflect the operational conditions of the road traffic system that influence the system's safety performance. SPIs were developed

  13. Factors Influencing the Performance of German Food SME Formal Networks

    Directory of Open Access Journals (Sweden)

    Jivka Deiters

    2014-08-01

    Full Text Available The food sector in Europe can be characterized as a complex, global and dynamically changing network of trade streams, food supply network relations and related product flows which offers a big spectrum for economic output and employment. Innovation is important for the competitiveness of the food industry that is to a large extent comprised of small and medium sized enterprises (SMEs. For them, innovation has grown extremely subordinate to interaction in networks. Network initiatives that could provide appropriate support involve social interaction and knowledge exchange, learning and competence development, and coordination (organization and management ofimplementation. This paper is designed to assess the factors that affect the performance of German food SME formal networks. It also addresses the consequences at the network and macro level. The analysis was explored by using the laddering technique based on the means‐end chain theory. The findings will help to build up a “network learning toolbox” that is adapted to the particular requirements of the different target groups such as of SMEs, network managers and policy makers. The “network learning toolbox” should improve network learning, which is adriver for improvements in innovation, economic growth and sustainable competitive advantage for food SMEs.

  14. Networked Mobilities and Performative Urban Environments

    DEFF Research Database (Denmark)

    Jensen, Ole B.

    , an increasing number of such mobile practices are mediated by technologies of tangible and less tangible sorts. Thus by focusing on the complex relationship between material and virtual technologies within the sphere of mobility it is shown that we need to move beyond dichotomies of; global or local, nomad...... or sedentary, digital or material. The paper investigates the meaning of mobility and the potential in mediation and technologies to enhance the experiences and interaction in relation to urban transit spaces. In understanding the importance of mediation, global-local interactions, networks....... By studying embedded technologies and ‘ambient environments' we increase our knowledge about the over layering of the material environment with digital technologies. The presences of GPS, mediated surfaces, mobile agents (robots), RFID and other technologies that all relate to contemporary mobility practices...

  15. Cross Deployment Networking and Systematic Performance Analysis of Underwater Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Zhengxian Wei

    2017-07-01

    Full Text Available Underwater wireless sensor networks (UWSNs have become a new hot research area. However, due to the work dynamics and harsh ocean environment, how to obtain an UWSN with the best systematic performance while deploying as few sensor nodes as possible and setting up self-adaptive networking is an urgent problem that needs to be solved. Consequently, sensor deployment, networking, and performance calculation of UWSNs are challenging issues, hence the study in this paper centers on this topic and three relevant methods and models are put forward. Firstly, the normal body-centered cubic lattice to cross body-centered cubic lattice (CBCL has been improved, and a deployment process and topology generation method are built. Then most importantly, a cross deployment networking method (CDNM for UWSNs suitable for the underwater environment is proposed. Furthermore, a systematic quar-performance calculation model (SQPCM is proposed from an integrated perspective, in which the systematic performance of a UWSN includes coverage, connectivity, durability and rapid-reactivity. Besides, measurement models are established based on the relationship between systematic performance and influencing parameters. Finally, the influencing parameters are divided into three types, namely, constraint parameters, device performance and networking parameters. Based on these, a networking parameters adjustment method (NPAM for optimized systematic performance of UWSNs has been presented. The simulation results demonstrate that the approach proposed in this paper is feasible and efficient in networking and performance calculation of UWSNs.

  16. Optical interconnection networks for high-performance computing systems

    International Nuclear Information System (INIS)

    Biberman, Aleksandr; Bergman, Keren

    2012-01-01

    Enabled by silicon photonic technology, optical interconnection networks have the potential to be a key disruptive technology in computing and communication industries. The enduring pursuit of performance gains in computing, combined with stringent power constraints, has fostered the ever-growing computational parallelism associated with chip multiprocessors, memory systems, high-performance computing systems and data centers. Sustaining these parallelism growths introduces unique challenges for on- and off-chip communications, shifting the focus toward novel and fundamentally different communication approaches. Chip-scale photonic interconnection networks, enabled by high-performance silicon photonic devices, offer unprecedented bandwidth scalability with reduced power consumption. We demonstrate that the silicon photonic platforms have already produced all the high-performance photonic devices required to realize these types of networks. Through extensive empirical characterization in much of our work, we demonstrate such feasibility of waveguides, modulators, switches and photodetectors. We also demonstrate systems that simultaneously combine many functionalities to achieve more complex building blocks. We propose novel silicon photonic devices, subsystems, network topologies and architectures to enable unprecedented performance of these photonic interconnection networks. Furthermore, the advantages of photonic interconnection networks extend far beyond the chip, offering advanced communication environments for memory systems, high-performance computing systems, and data centers. (review article)

  17. Investigation of road network features and safety performance.

    Science.gov (United States)

    Wang, Xuesong; Wu, Xingwei; Abdel-Aty, Mohamed; Tremont, Paul J

    2013-07-01

    The analysis of road network designs can provide useful information to transportation planners as they seek to improve the safety of road networks. The objectives of this study were to compare and define the effective road network indices and to analyze the relationship between road network structure and traffic safety at the level of the Traffic Analysis Zone (TAZ). One problem in comparing different road networks is establishing criteria that can be used to scale networks in terms of their structures. Based on data from Orange and Hillsborough Counties in Florida, road network structural properties within TAZs were scaled using 3 indices: Closeness Centrality, Betweenness Centrality, and Meshedness Coefficient. The Meshedness Coefficient performed best in capturing the structural features of the road network. Bayesian Conditional Autoregressive (CAR) models were developed to assess the safety of various network configurations as measured by total crashes, crashes on state roads, and crashes on local roads. The models' results showed that crash frequencies on local roads were closely related to factors within the TAZs (e.g., zonal network structure, TAZ population), while crash frequencies on state roads were closely related to the road and traffic features of state roads. For the safety effects of different networks, the Grid type was associated with the highest frequency of crashes, followed by the Mixed type, the Loops & Lollipops type, and the Sparse type. This study shows that it is possible to develop a quantitative scale for structural properties of a road network, and to use that scale to calculate the relationships between network structural properties and safety. Copyright © 2013 Elsevier Ltd. All rights reserved.

  18. The impact of network characteristics on the diffusion of innovations

    Science.gov (United States)

    Peres, Renana

    2014-05-01

    This paper studies the influence of network topology on the speed and reach of new product diffusion. While previous research has focused on comparing network types, this paper explores explicitly the relationship between topology and measurements of diffusion effectiveness. We study simultaneously the effect of three network metrics: the average degree, the relative degree of social hubs (i.e., the ratio of the average degree of highly-connected individuals to the average degree of the entire population), and the clustering coefficient. A novel network-generation procedure based on random graphs with a planted partition is used to generate 160 networks with a wide range of values for these topological metrics. Using an agent-based model, we simulate diffusion on these networks and check the dependence of the net present value (NPV) of the number of adopters over time on the network metrics. We find that the average degree and the relative degree of social hubs have a positive influence on diffusion. This result emphasizes the importance of high network connectivity and strong hubs. The clustering coefficient has a negative impact on diffusion, a finding that contributes to the ongoing controversy on the benefits and disadvantages of transitivity. These results hold for both monopolistic and duopolistic markets, and were also tested on a sample of 12 real networks.

  19. Structural integration and performance of inter-sectoral public health-related policy networks: An analysis across policy phases.

    Science.gov (United States)

    Peters, D T J M; Raab, J; Grêaux, K M; Stronks, K; Harting, J

    2017-12-01

    Inter-sectoral policy networks may be effective in addressing environmental determinants of health with interventions. However, contradictory results are reported on relations between structural network characteristics (i.e., composition and integration) and network performance, such as addressing environmental determinants of health. This study examines these relations in different phases of the policy process. A multiple-case study was performed on four public health-related policy networks. Using a snowball method among network actors, overall and sub-networks per policy phase were identified and the policy sector of each actor was assigned. To operationalise the outcome variable, interventions were classified by the proportion of environmental determinants they addressed. In the overall networks, no relation was found between structural network characteristics and network performance. In most effective cases, the policy development sub-networks were characterised by integration with less interrelations between actors (low cohesion), more equally distributed distances between the actors (low closeness centralisation), and horizontal integration in inter-sectoral cliques. The most effective case had non-public health central actors with less connections in all sub-networks. The results suggest that, to address environmental determinants of health, sub-networks should be inter-sectorally composed in the policy development rather than in the intervention development and implementation phases, and that policy development actors should have the opportunity to connect with other actors, without strong direction from a central actor. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Research of psychological characteristics and performance relativity of operators

    International Nuclear Information System (INIS)

    Fang Xiang; He Xuhong; Zhao Bingquan

    2008-01-01

    Based on the working tasks of an operator being taken into full consideration in this paper, on the one hand the table of measuring psychological characteristics is designed through the selection of special dimensions; on the other hand the table of performance appraisal is drafted through the choice of suitable standards of an operator. The paper analyzes the results of two aspects, sets relevant nuclear power plant operators as the research objective, and obtains the psychological characteristics and performance relativity of operators. The research can be as important and applied reference for the selection, evaluation and use of operators

  1. Performance and complexity of tunable sparse network coding with gradual growing tuning functions over wireless networks

    OpenAIRE

    Garrido Ortiz, Pablo; Sørensen, Chres W.; Lucani Roetter, Daniel Enrique; Agüero Calvo, Ramón

    2016-01-01

    Random Linear Network Coding (RLNC) has been shown to be a technique with several benefits, in particular when applied over wireless mesh networks, since it provides robustness against packet losses. On the other hand, Tunable Sparse Network Coding (TSNC) is a promising concept, which leverages a trade-off between computational complexity and goodput. An optimal density tuning function has not been found yet, due to the lack of a closed-form expression that links density, performance and comp...

  2. Identifying protein complex by integrating characteristic of core-attachment into dynamic PPI network.

    Directory of Open Access Journals (Sweden)

    Xianjun Shen

    Full Text Available How to identify protein complex is an important and challenging task in proteomics. It would make great contribution to our knowledge of molecular mechanism in cell life activities. However, the inherent organization and dynamic characteristic of cell system have rarely been incorporated into the existing algorithms for detecting protein complexes because of the limitation of protein-protein interaction (PPI data produced by high throughput techniques. The availability of time course gene expression profile enables us to uncover the dynamics of molecular networks and improve the detection of protein complexes. In order to achieve this goal, this paper proposes a novel algorithm DCA (Dynamic Core-Attachment. It detects protein-complex core comprising of continually expressed and highly connected proteins in dynamic PPI network, and then the protein complex is formed by including the attachments with high adhesion into the core. The integration of core-attachment feature into the dynamic PPI network is responsible for the superiority of our algorithm. DCA has been applied on two different yeast dynamic PPI networks and the experimental results show that it performs significantly better than the state-of-the-art techniques in terms of prediction accuracy, hF-measure and statistical significance in biology. In addition, the identified complexes with strong biological significance provide potential candidate complexes for biologists to validate.

  3. Classification of Company Performance using Weighted Probabilistic Neural Network

    Science.gov (United States)

    Yasin, Hasbi; Waridi Basyiruddin Arifin, Adi; Warsito, Budi

    2018-05-01

    Classification of company performance can be judged by looking at its financial status, whether good or bad state. Classification of company performance can be achieved by some approach, either parametric or non-parametric. Neural Network is one of non-parametric methods. One of Artificial Neural Network (ANN) models is Probabilistic Neural Network (PNN). PNN consists of four layers, i.e. input layer, pattern layer, addition layer, and output layer. The distance function used is the euclidean distance and each class share the same values as their weights. In this study used PNN that has been modified on the weighting process between the pattern layer and the addition layer by involving the calculation of the mahalanobis distance. This model is called the Weighted Probabilistic Neural Network (WPNN). The results show that the company's performance modeling with the WPNN model has a very high accuracy that reaches 100%.

  4. Performance analysis and improvement of WPAN MAC for home networks.

    Science.gov (United States)

    Mehta, Saurabh; Kwak, Kyung Sup

    2010-01-01

    The wireless personal area network (WPAN) is an emerging wireless technology for future short range indoor and outdoor communication applications. The IEEE 802.15.3 medium access control (MAC) is proposed to coordinate the access to the wireless medium among the competing devices, especially for short range and high data rate applications in home networks. In this paper we use analytical modeling to study the performance analysis of WPAN (IEEE 802.15.3) MAC in terms of throughput, efficient bandwidth utilization, and delay with various ACK policies under error channel condition. This allows us to introduce a K-Dly-ACK-AGG policy, payload size adjustment mechanism, and Improved Backoff algorithm to improve the performance of the WPAN MAC. Performance evaluation results demonstrate the impact of our improvements on network capacity. Moreover, these results can be very useful to WPAN application designers and protocol architects to easily and correctly implement WPAN for home networking.

  5. Performance Analysis and Improvement of WPAN MAC for Home Networks

    Directory of Open Access Journals (Sweden)

    Saurabh Mehta

    2010-03-01

    Full Text Available The wireless personal area network (WPAN is an emerging wireless technology for future short range indoor and outdoor communication applications. The IEEE 802.15.3 medium access control (MAC is proposed to coordinate the access to the wireless medium among the competing devices, especially for short range and high data rate applications in home networks. In this paper we use analytical modeling to study the performance analysis of WPAN (IEEE 802.15.3 MAC in terms of throughput, efficient bandwidth utilization, and delay with various ACK policies under error channel condition. This allows us to introduce a K-Dly-ACK-AGG policy, payload size adjustment mechanism, and Improved Backoff algorithm to improve the performance of the WPAN MAC. Performance evaluation results demonstrate the impact of our improvements on network capacity. Moreover, these results can be very useful to WPAN application designers and protocol architects to easily and correctly implement WPAN for home networking.

  6. Optical Performance Monitoring and Signal Optimization in Optical Networks

    DEFF Research Database (Denmark)

    Petersen, Martin Nordal

    2006-01-01

    The thesis studies performance monitoring for the next generation optical networks. The focus is on all-optical networks with bit-rates of 10 Gb/s or above. Next generation all-optical networks offer large challenges as the optical transmitted distance increases and the occurrence of electrical-optical......-electrical regeneration points decreases. This thesis evaluates the impact of signal degrading effects that are becoming of increasing concern in all-optical high-speed networks due to all-optical switching and higher bit-rates. Especially group-velocity-dispersion (GVD) and a number of nonlinear effects will require...... enhanced attention to avoid signal degradations. The requirements for optical performance monitoring features are discussed, and the thesis evaluates the advantages and necessity of increasing the level of performance monitoring parameters in the physical layer. In particular, methods for optical...

  7. Intra-burst firing characteristics as network state parameters

    NARCIS (Netherlands)

    Stegenga, J.; le Feber, Jakob; Rutten, Wim; Marani, Enrico; Stett, A

    Introduction In our group we are aiming to demonstrate learning and memory capabilities of cultured networks of cortical neurons. A first step is to identify parameters that accurately describe changes in the network due to learning. Usually, such parameters are calculated from the responses to

  8. Modeling Travel Time Reliability of Road Network Considering Connected Vehicle Guidance Characteristics Indexes

    Directory of Open Access Journals (Sweden)

    Jiangfeng Wang

    2017-01-01

    Full Text Available Travel time reliability (TTR is one of the important indexes for effectively evaluating the performance of road network, and TTR can effectively be improved using the real-time traffic guidance information. Compared with traditional traffic guidance, connected vehicle (CV guidance can provide travelers with more timely and accurate travel information, which can further improve the travel efficiency of road network. Five CV characteristics indexes are selected as explanatory variables including the Congestion Level (CL, Penetration Rate (PR, Compliance Rate (CR, release Delay Time (DT, and Following Rate (FR. Based on the five explanatory variables, a TTR model is proposed using the multilogistic regression method, and the prediction accuracy and the impact of characteristics indexes on TTR are analyzed using a CV guidance scenario. The simulation results indicate that 80% of the RMSE is concentrated within the interval of 0 to 0.0412. The correlation analysis of characteristics indexes shows that the influence of CL, PR, CR, and DT on the TTR is significant. PR and CR have a positive effect on TTR, and the average improvement rate is about 77.03% and 73.20% with the increase of PR and CR, respectively, while CL and DT have a negative effect on TTR, and TTR decreases by 31.21% with the increase of DT from 0 to 180 s.

  9. Multiplex network analysis of employee performance and employee social relationships

    Science.gov (United States)

    Cai, Meng; Wang, Wei; Cui, Ying; Stanley, H. Eugene

    2018-01-01

    In human resource management, employee performance is strongly affected by both formal and informal employee networks. Most previous research on employee performance has focused on monolayer networks that can represent only single categories of employee social relationships. We study employee performance by taking into account the entire multiplex structure of underlying employee social networks. We collect three datasets consisting of five different employee relationship categories in three firms, and predict employee performance using degree centrality and eigenvector centrality in a superimposed multiplex network (SMN) and an unfolded multiplex network (UMN). We use a quadratic assignment procedure (QAP) analysis and a regression analysis to demonstrate that the different categories of relationship are mutually embedded and that the strength of their impact on employee performance differs. We also use weighted/unweighted SMN/UMN to measure the predictive accuracy of this approach and find that employees with high centrality in a weighted UMN are more likely to perform well. Our results shed new light on how social structures affect employee performance.

  10. Personal and Network Dynamics in Performance of Knowledge Workers: A Study of Australian Breast Radiologists.

    Directory of Open Access Journals (Sweden)

    Seyedamir Tavakoli Taba

    Full Text Available In this paper, we propose a theoretical model based upon previous studies about personal and social network dynamics of job performance. We provide empirical support for this model using real-world data within the context of the Australian radiology profession. An examination of radiologists' professional network topology through structural-positional and relational dimensions and radiologists' personal characteristics in terms of knowledge, experience and self-esteem is provided. Thirty one breast imaging radiologists completed a purpose designed questionnaire regarding their network characteristics and personal attributes. These radiologists also independently read a test set of 60 mammographic cases: 20 cases with cancer and 40 normal cases. A Jackknife free response operating characteristic (JAFROC method was used to measure the performance of the radiologists' in detecting breast cancers.Correlational analyses showed that reader performance was positively correlated with the social network variables of degree centrality and effective size, but negatively correlated with constraint and hierarchy. For personal characteristics, the number of mammograms read per year and self-esteem (self-evaluation positively correlated with reader performance. Hierarchical multiple regression analysis indicated that the combination of number of mammograms read per year and network's effective size, hierarchy and tie strength was the best fitting model, explaining 63.4% of the variance in reader performance. The results from this study indicate the positive relationship between reading high volumes of cases by radiologists and expertise development, but also strongly emphasise the association between effective social/professional interactions and informal knowledge sharing with high performance.

  11. Performability indicators for the traffic analysis of wide area networks

    International Nuclear Information System (INIS)

    Tsopelas, Panagiotis; Platis, Agapios

    2003-01-01

    In connecting computing networks, reliability term is strongly related to the availability of connections of Wide Area networks (WANs) or Local Area networks (LANs). In this paper we will examine the network connections activity of a Greek University in order to provide two sources of information: The Quantity of Information Not Delivered (QIND) and the Information Flow Interruption (IFI). These indicators will provide us with the inference of information from observable characteristics of data flow(s), even when the data is encrypted or otherwise not directly available (traffic), which is lost due to failures or upgrades inside this network. The reliability analysis is obtained by collecting the network failures data (duration and frequency) and traffic (total and average) for a specified period of 1 year. It is assumed that the numerical analysis is based on the fact that the lifetime follows and exponential distribution (here as we are working on discrete time the distribution must be the geometric distribution). Hence a Markov chain model seems suitable for modelling the functioning of this system. An algorithm concentrates the results in a transition probability matrix and calculates the reward functions for the QIND/IFI indicators with the use of the power method. Finally, the application part provides an example of how final results can be used to evaluate the observed network

  12. Facebook use, personality characteristics and academic performance: A correlational study

    OpenAIRE

    Sapsani, Georgia; Tselios, Nikolaos

    2017-01-01

    The present paper examines the relationship between the students personality, use of social media and their academic performance and engagement. In specific, the aim of this study is to examine the relationship of students facebook (fb) use and personality characteristics using the Big Five Personality Test with (a) student engagement, (b) time spent preparing for class, (c) time spent in co-curricular activities and (d) academic performance. Results illustrate that fb time was significantly ...

  13. Performance Characteristics of an Armature Voltage Controlled D.C. ...

    African Journals Online (AJOL)

    In this paper, the performance study of a separately excited d. c. motor whose speed is controlled by armature voltage variation is presented. Both the open loop and the closed loop steady state and transient characteristics are reported. The speed controllers considered in the closed loop mode are the proportional and the ...

  14. Performance and Carcass Characteristics of Broiler Finisher Birds ...

    African Journals Online (AJOL)

    Sixty (60) 4 weeks old Anak broiler strain were subjected to 28 days feeding trial at the Poultry Unit of the Teaching and Research Farm, Evan Enwerem, Owerri, Nigeria, to determine the dietary effect of pineapple wine sediment (PWSM) on their performance and carcass characteristics. The birds were divided into four ...

  15. Do the Managerial Characteristics of Schools Influence Their Performance?

    Science.gov (United States)

    Agasisti, Tommaso; Bonomi, Francesca; Sibiano, Piergiacomo

    2012-01-01

    Purpose: The purpose of this paper is to investigate the role of governance and managerial characteristics of schools. More specifically, the aim is to individuate the factors that are associated to higher schools' performances, as measured through student achievement. Design/methodology/approach: The research is conducted by means of a survey in…

  16. Performance characteristics of proximity focused ultraviolet image converters

    Science.gov (United States)

    Williams, J. T.; Feibelman, W. A.

    1973-01-01

    Performance characteristics of Bendix type BX 8025-4522 proximity focused image tubes for UV to visible light conversion are presented. Quantum efficiency, resolution, background, geometric distortion, and environmental test results are discussed. The converters use magnesium fluoride input windows with Cs-Te photocathodes and P-11 phosphors on fiber optic output windows.

  17. Growth performance, carcass and organ characteristics of growing ...

    African Journals Online (AJOL)

    An experiment was conducted at the Department of Animal Science teaching and research farm, Bayero University Kano, to evaluate the effect of feeding graded levels of Moringa oleifera leaf meal (MOLM) in diets on growth performance, carcass and organ characteristics of weaned rabbits. Twenty eight grower rabbits of ...

  18. Performance and ileal characteristics of finishing broilers fed diets ...

    African Journals Online (AJOL)

    An experiment was conducted to evaluate the effect of prebiotics supplemented diets on performance characteristics and gut morphology of broiler chickens. The study involved 320 day-old Anak broiler chicks, used to assess the utilization of prebiotics [Mannose oligosaccharides (MOS) and Lactose oligosaccharides ...

  19. Nonlinear performance characteristics of flux-switching PM motors

    NARCIS (Netherlands)

    Ilhan, E.; Kremers, M.F.J.; Motoasca, T.E.; Paulides, J.J.H.; Lomonova, E.

    2013-01-01

    Nonlinear performance characteristics of 3-phase flux-switching permanent magnet motors (FSPM) are overviewed. These machines show advantages of a robust rotor structure and a high energy density. Research on the FSPM is predominated by topics such as modeling and machine comparison, with little

  20. Performance characteristics of broiler chicks fed kidney bean as ...

    African Journals Online (AJOL)

    An experiment was conducted to investigate the effect of replacing soybean meal and groundnut cake meal with cooked and decorticated kidney bean seed meals on the performance characteristics of broilers. One hundred and eighty day old broiler chicks of Anak strain were raised on six experimental diets.

  1. Characteristics of group networks in the KOSPI and the KOSDAQ

    Science.gov (United States)

    Kim, Kyungsik; Ko, Jeung-Su; Yi, Myunggi

    2012-02-01

    We investigate the main feature of group networks in the KOSPI and KOSDAQ of Korean financial markets and analyze daily cross-correlations between price fluctuations for the 5-year time period from 2006 to 2010. We discuss the stabilities by undressing the market-wide effect using the Markowitz multi-factor model and the network-based approach. In particular we ascertain the explicit list of significant firms in the few largest eigenvectors from the undressed correlation matrix. Finally, we show the structure of group correlation by applying a network-based approach. In addition, the relation between market capitalizations and businesses is examined.

  2. Network characteristics, perceived social support, and psychological adjustment in mothers of children with autism spectrum disorder.

    Science.gov (United States)

    Benson, Paul R

    2012-12-01

    This study examined the characteristics of the support networks of 106 mothers of children with ASD and their relationship to perceived social support, depressed mood, and subjective well-being. Using structural equation modeling, two competing sets of hypotheses were assessed: (1) that network characteristics would impact psychological adjustment directly, and (2) that network effects on adjustment would be indirect, mediated by perceived social support. Results primarily lent support to the latter hypotheses, with measures of network structure (network size) and function (proportion of network members providing emotional support) predicting increased levels of perceived social support which, in turn, predicted decreased depressed mood and increased well-being. Results also indicated that increased interpersonal strain in the maternal network was directly and indirectly associated with increased maternal depression, while being indirectly linked to reduced well-being. Study limitations and implications are discussed.

  3. Effects of the bipartite structure of a network on performance of recommenders

    Science.gov (United States)

    Wang, Qing-Xian; Li, Jian; Luo, Xin; Xu, Jian-Jun; Shang, Ming-Sheng

    2018-02-01

    Recommender systems aim to predict people's preferences for online items by analyzing their historical behaviors. A recommender can be modeled as a high-dimensional and sparse bipartite network, where the key issue is to understand the relation between the network structure and a recommender's performance. To address this issue, we choose three network characteristics, clustering coefficient, network density and user-item ratio, as the analyzing targets. For the cluster coefficient, we adopt the Degree-preserving rewiring algorithm to obtain a series of bipartite network with varying cluster coefficient, while the degree of user and item keep unchanged. Furthermore, five state-of-the-art recommenders are applied on two real datasets. The performances of recommenders are measured by both numerical and physical metrics. These results show that a recommender's performance is positively related to the clustering coefficient of a bipartite network. Meanwhile, higher density of a bipartite network can provide more accurate but less diverse or novel recommendations. Furthermore, the user-item ratio is positively correlated with the accuracy metrics but negatively correlated with the diverse and novel metrics.

  4. Sustainable Performance in Energy Harvesting - Wireless Sensor Networks

    DEFF Research Database (Denmark)

    Fafoutis, Xenofon; Di Mauro, Alessio; Dragoni, Nicola

    2013-01-01

    In this practical demo we illustrate the concept of "sustainable performance" in Energy-Harvesting Wireless Sensor Networks (EH-WSNs). In particular, for different classes of applications and under several energy harvesting scenarios, we show how it is possible to have sustainable performance when...

  5. The Enhancing Impact of Friendship Networks on Sales Managers’ Performance

    Directory of Open Access Journals (Sweden)

    Danny Pimentel Claro

    2013-04-01

    Full Text Available This paper examines how relationships with friends moderate the impact of professional networks on sales performance. Based on a sample of 204 sales managers in a professional service company, this study presents evidence that friendship networks amplify the effect of sales forces’ professional networks on new product sales as well as on prospecting and converting new deals. Our results offer important insights into the socio-cognitive perspective of sales management literature and suggest that firms should encourage managers to improve their friendships in order to access valuable information that will enhance customer knowledge and support their sales efforts.

  6. Statistical performance evaluation of ECG transmission using wireless networks.

    Science.gov (United States)

    Shakhatreh, Walid; Gharaibeh, Khaled; Al-Zaben, Awad

    2013-07-01

    This paper presents simulation of the transmission of biomedical signals (using ECG signal as an example) over wireless networks. Investigation of the effect of channel impairments including SNR, pathloss exponent, path delay and network impairments such as packet loss probability; on the diagnosability of the received ECG signal are presented. The ECG signal is transmitted through a wireless network system composed of two communication protocols; an 802.15.4- ZigBee protocol and an 802.11b protocol. The performance of the transmission is evaluated using higher order statistics parameters such as kurtosis and Negative Entropy in addition to the common techniques such as the PRD, RMS and Cross Correlation.

  7. Full-Duplex MIMO Small-Cell Networks: Performance Analysis

    OpenAIRE

    Atzeni, Italo; Kountouris, Marios

    2015-01-01

    Full-duplex small-cell relays with multiple antennas constitute a core element of the envisioned 5G network architecture. In this paper, we use stochastic geometry to analyze the performance of wireless networks with full-duplex multiple-antenna small cells, with particular emphasis on the probability of successful transmission. To achieve this goal, we additionally characterize the distribution of the self-interference power of the full-duplex nodes. The proposed framework reveals useful ins...

  8. Job characteristics, flow, and performance: the moderating role of conscientiousness.

    Science.gov (United States)

    Demerouti, Evangelia

    2006-07-01

    The present article aims to show the importance of positive work-related experiences within occupational health psychology by examining the relationship between flow at work (i.e., absorption, work enjoyment, and intrinsic work motivation) and job performance. On the basis of the literature, it was hypothesized that (a) motivating job characteristics are positively related to flow at work and (b) conscientiousness moderates the relationship between flow and other ratings of (in-role and out-of-role) performance. The hypotheses were tested on a sample of 113 employees from several occupations. Results of moderated structural equation modeling analyses generally supported the hypotheses. Motivating job characteristics were predictive of flow, and flow predicted in-role and extra-role performance, for only conscientious employees.

  9. Parametric study of geohydrologic performance characteristics for geologic waste repositories

    International Nuclear Information System (INIS)

    Bailey, C.E.; Marine, I.W.

    1980-11-01

    One of the major objectives of the National Waste Terminal Storage Program is to identify potential geologic sites for storage and isolation of radioactive waste (and possibly irradiated fuel). Potential sites for the storage and isolation of radioactive waste or spent fuel in a geologic rock unit are being carefully evaluated to ensure that radionuclides from the stored waste or fuel will never appear in the biosphere in amounts that would constitute a hazard to the health and safety of the public. The objective of this report is to quantify and present in graphical form the effects of significant geohydrologic and other performance characteristics that would influence the movement of radionuclides from a storage site in a rock unit to the biosphere. The effort in this study was focused on transport by groundwater because that is the most likely method of radionuclide escape. Graphs of the major performance characteristics that influence the transport of radionuclides from a repository to the biosphere by groundwater are presented. The major characteristics addressed are radioactive decay, leach rate, hydraulic conductivity, porosity, groundwater gradient, hydrodynamic dispersion, ion exchange, and distance to the biosphere. These major performance characteristics are combind with each other and with the results of certain other combinations and presented in graphical form to provide the interrelationships of values measured during field studies. The graphical form of presentation should be useful in the screening process of site selection. An appendix illustrates the use of these graphs to assess the suitability of a site

  10. Hospital network performance: a survey of hospital stakeholders' perspectives.

    Science.gov (United States)

    Bravi, F; Gibertoni, D; Marcon, A; Sicotte, C; Minvielle, E; Rucci, P; Angelastro, A; Carradori, T; Fantini, M P

    2013-02-01

    Hospital networks are an emerging organizational form designed to face the new challenges of public health systems. Although the benefits introduced by network models in terms of rationalization of resources are known, evidence about stakeholders' perspectives on hospital network performance from the literature is scanty. Using the Competing Values Framework of organizational effectiveness and its subsequent adaptation by Minvielle et al., we conducted in 2009 a survey in five hospitals of an Italian network for oncological care to examine and compare the views on hospital network performance of internal stakeholders (physicians, nurses and the administrative staff). 329 questionnaires exploring stakeholders' perspectives were completed, with a response rate of 65.8%. Using exploratory factor analysis of the 66 items of the questionnaire, we identified 4 factors, i.e. Centrality of relationships, Quality of care, Attractiveness/Reputation and Staff empowerment and Protection of workers' rights. 42 items were retained in the analysis. Factor scores proved to be high (mean score>8 on a 10-item scale), except for Attractiveness/Reputation (mean score 6.79), indicating that stakeholders attach a higher importance to relational and health care aspects. Comparison of factor scores among stakeholders did not reveal significant differences, suggesting a broadly shared view on hospital network performance. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  11. General performance characteristics of an irreversible ferromagnetic Stirling refrigeration cycle

    International Nuclear Information System (INIS)

    Lin, G.; Tegus, O.; Zhang, L.; Brueck, E.

    2004-01-01

    A new magnetic-refrigeration-cycle model using ferromagnetic materials as a cyclic working substance is set up, in which finite-rate heat transfer, heat leak and regeneration time are taken into account. On the basis of the thermodynamic properties of a ferromagnetic material, the general performance characteristics of the ferromagnetic Stirling refrigeration cycle are investigated and the effects of some key irreversibilities on the performance of the cycle are revealed. By using the optimal-control theory, the optimal relation between the coefficient of performance and the cooling rate is derived and some important performance bounds, e.g., the maximum cooling rate, the maximum coefficient of performance, are determined. Moreover, the optimal operating regions for cooling rate, coefficient of performance and the optimal operating temperatures of a cyclic working substance in the two heat-transfer processes are obtained. Furthermore, the influences of magnetization and magnetic field on the performance characteristics of the cycle are discussed. The results obtained here have general significance and can be deduced to the related ones of the Stirling refrigeration cycle using paramagnetic salt as a cyclic working substance

  12. Prediction of vibration characteristics of a planar mechanism having imperfect joints using neural network

    International Nuclear Information System (INIS)

    Erkaya, Selcuk

    2012-01-01

    Clearance is inevitable in the joints of mechanisms due primarily to the design, manufacturing and assembly processes or a wear effect. Excessive value of joint clearance plays a crucial role and has a significant effect on the kinematic and dynamic performances of the mechanism. In this study, effects of joint clearances on bearing vibrations of mechanism are investigated. An experimental test rig is set up, and a planar slider-crank mechanism having two imperfect joints with radial clearance is used as a model mechanism. Three accelerometers are positioned at different points to measure the bearing vibrations during the mechanism motion. For the different running speeds and clearance sizes, this work provides a neural model to predict and estimate the bearing vibrations of the mechanical systems having imperfect joints. The results show that radial basis function (RBF) neural network has a superior performance for predicting and estimating the vibration characteristics of the mechanical system

  13. The geospatial characteristics of a social movement communication network.

    Science.gov (United States)

    Conover, Michael D; Davis, Clayton; Ferrara, Emilio; McKelvey, Karissa; Menczer, Filippo; Flammini, Alessandro

    2013-01-01

    Social movements rely in large measure on networked communication technologies to organize and disseminate information relating to the movements' objectives. In this work we seek to understand how the goals and needs of a protest movement are reflected in the geographic patterns of its communication network, and how these patterns differ from those of stable political communication. To this end, we examine an online communication network reconstructed from over 600,000 tweets from a thirty-six week period covering the birth and maturation of the American anticapitalist movement, Occupy Wall Street. We find that, compared to a network of stable domestic political communication, the Occupy Wall Street network exhibits higher levels of locality and a hub and spoke structure, in which the majority of non-local attention is allocated to high-profile locations such as New York, California, and Washington D.C. Moreover, we observe that information flows across state boundaries are more likely to contain framing language and references to the media, while communication among individuals in the same state is more likely to reference protest action and specific places and times. Tying these results to social movement theory, we propose that these features reflect the movement's efforts to mobilize resources at the local level and to develop narrative frames that reinforce collective purpose at the national level.

  14. Energy efficient mechanisms for high-performance Wireless Sensor Networks

    Science.gov (United States)

    Alsaify, Baha'adnan

    2009-12-01

    Due to recent advances in microelectronics, the development of low cost, small, and energy efficient devices became possible. Those advances led to the birth of the Wireless Sensor Networks (WSNs). WSNs consist of a large set of sensor nodes equipped with communication capabilities, scattered in the area to monitor. Researchers focus on several aspects of WSNs. Such aspects include the quality of service the WSNs provide (data delivery delay, accuracy of data, etc...), the scalability of the network to contain thousands of sensor nodes (the terms node and sensor node are being used interchangeably), the robustness of the network (allowing the network to work even if a certain percentage of nodes fails), and making the energy consumption in the network as low as possible to prolong the network's lifetime. In this thesis, we present an approach that can be applied to the sensing devices that are scattered in an area for Sensor Networks. This work will use the well-known approach of using a awaking scheduling to extend the network's lifespan. We designed a scheduling algorithm that will reduce the delay's upper bound the reported data will experience, while at the same time keeps the advantages that are offered by the use of the awaking scheduling -- the energy consumption reduction which will lead to the increase in the network's lifetime. The wakeup scheduling is based on the location of the node relative to its neighbors and its distance from the Base Station (the terms Base Station and sink are being used interchangeably). We apply the proposed method to a set of simulated nodes using the "ONE Simulator". We test the performance of this approach with three other approaches -- Direct Routing technique, the well known LEACH algorithm, and a multi-parent scheduling algorithm. We demonstrate a good improvement on the network's quality of service and a reduction of the consumed energy.

  15. Network Signaling Channel for Improving ZigBee Performance in Dynamic Cluster-Tree Networks

    Directory of Open Access Journals (Sweden)

    D. Hämäläinen

    2008-03-01

    Full Text Available ZigBee is one of the most potential standardized technologies for wireless sensor networks (WSNs. Yet, sufficient energy-efficiency for the lowest power WSNs is achieved only in rather static networks. This severely limits the applicability of ZigBee in outdoor and mobile applications, where operation environment is harsh and link failures are common. This paper proposes a network channel beaconing (NCB algorithm for improving ZigBee performance in dynamic cluster-tree networks. NCB reduces the energy consumption of passive scans by dedicating one frequency channel for network beacon transmissions and by energy optimizing their transmission rate. According to an energy analysis, the power consumption of network maintenance operations reduces by 70%–76% in dynamic networks. In static networks, energy overhead is negligible. Moreover, the service time for data routing increases up to 37%. The performance of NCB is validated by ns-2 simulations. NCB can be implemented as an extension on MAC and NWK layers and it is fully compatible with ZigBee.

  16. Virtual Networking Performance in OpenStack Platform for Network Function Virtualization

    Directory of Open Access Journals (Sweden)

    Franco Callegati

    2016-01-01

    Full Text Available The emerging Network Function Virtualization (NFV paradigm, coupled with the highly flexible and programmatic control of network devices offered by Software Defined Networking solutions, enables unprecedented levels of network virtualization that will definitely change the shape of future network architectures, where legacy telco central offices will be replaced by cloud data centers located at the edge. On the one hand, this software-centric evolution of telecommunications will allow network operators to take advantage of the increased flexibility and reduced deployment costs typical of cloud computing. On the other hand, it will pose a number of challenges in terms of virtual network performance and customer isolation. This paper intends to provide some insights on how an open-source cloud computing platform such as OpenStack implements multitenant network virtualization and how it can be used to deploy NFV, focusing in particular on packet forwarding performance issues. To this purpose, a set of experiments is presented that refer to a number of scenarios inspired by the cloud computing and NFV paradigms, considering both single tenant and multitenant scenarios. From the results of the evaluation it is possible to highlight potentials and limitations of running NFV on OpenStack.

  17. Multidimensional performance characteristics and standard of performance in talented youth field hockey players : A longitudinal study

    NARCIS (Netherlands)

    Elferink-Gemser, Marije T.; Visscher, Chris; Lemmink, Koen A. P. M.; Mulder, Theo

    2007-01-01

    To identify performance characteristics that could help predict future elite field hockey players, we measured the anthropometric, physiological, technical, tactical, and psychological characteristics of 30 elite and 35 sub-elite youth players at the end of three consecutive seasons. The mean age of

  18. Influence of prey body characteristics and performance on predator selection.

    Science.gov (United States)

    Holmes, Thomas H; McCormick, Mark I

    2009-03-01

    At the time of settlement to the reef environment, coral reef fishes differ in a number of characteristics that may influence their survival during a predatory encounter. This study investigated the selective nature of predation by both a multi-species predator pool, and a single common predator (Pseudochromis fuscus), on the reef fish, Pomacentrus amboinensis. The study focused on the early post-settlement period of P. amboinensis, when mortality, and hence selection, is known to be highest. Correlations between nine different measures of body condition/performance were examined at the time of settlement, in order to elucidate the relationships between different traits. Single-predator (P. fuscus) choice trials were conducted in 57.4-l aquaria with respect to three different prey characteristics [standard length (SL), body weight and burst swimming speed], whilst multi-species trials were conducted on open patch reefs, manipulating prey body weight only. Relationships between the nine measures of condition/performance were generally poor, with the strongest correlations occurring between the morphological measures and within the performance measures. During aquaria trials, P. fuscus was found to be selective with respect to prey SL only, with larger individuals being selected significantly more often. Multi-species predator communities, however, were selective with respect to prey body weight, with heavier individuals being selected significantly more often than their lighter counterparts. Our results suggest that under controlled conditions, body length may be the most important prey characteristic influencing prey survival during predatory encounters with P. fuscus. In such cases, larger prey size may actually be a distinct disadvantage to survival. However, these relationships appear to be more complex under natural conditions, where the expression of prey characteristics, the selectivity fields of a number of different predators, their relative abundance, and

  19. RELATIONSHIPS BETWEEN MUSCLE FATIGUE CHARACTERISTICS AND MARKERS OF ENDURANCE PERFORMANCE

    Directory of Open Access Journals (Sweden)

    Martyn G. Morris

    2008-12-01

    Full Text Available The aim of this study was to examine the relationship of a range of in-vivo whole muscle characteristics to determinants of endurance performance. Eleven healthy males completed a cycle ergometer step test to exhaustion for the determination of the lactate threshold, gross mechanical efficiency, peak power and VO2max. On two separate occasions, contractile and fatigue characteristics of the quadriceps femoris were collected using a specially designed isometric strength-testing chair. Muscle fatigue was then assessed by stimulating the muscle for 3 minutes. Force, rate of force development and rates of relaxation were calculated at the beginning and end of the 3 minute protocol and examined for reliability and in relation to lactate threshold, VO2max, gross mechanical efficiency and peak power. Muscle characteristics, rate of force development and relaxation rate were demonstrated to be reliable measures. Force drop off over the 3 minutes (fatigue index was related to lactate threshold (r = -0.72 p < 0.01 but not to VO2max. The rate of force development related to the peak power at the end of the cycle ergometer test (r = -0.75 p < 0.01. Rates of relaxation did not relate to any of the performance markers. We found in-vivo whole muscle characteristics, such as the fatigue index and rate of force development, relate to specific markers of peripheral, but not to central, fitness components. Our investigation suggests that muscle characteristics assessed in this way is reliable and could be feasibly utilised to further our understanding of the peripheral factors underpinning performance

  20. GeneNetWeaver: in silico benchmark generation and performance profiling of network inference methods.

    Science.gov (United States)

    Schaffter, Thomas; Marbach, Daniel; Floreano, Dario

    2011-08-15

    Over the last decade, numerous methods have been developed for inference of regulatory networks from gene expression data. However, accurate and systematic evaluation of these methods is hampered by the difficulty of constructing adequate benchmarks and the lack of tools for a differentiated analysis of network predictions on such benchmarks. Here, we describe a novel and comprehensive method for in silico benchmark generation and performance profiling of network inference methods available to the community as an open-source software called GeneNetWeaver (GNW). In addition to the generation of detailed dynamical models of gene regulatory networks to be used as benchmarks, GNW provides a network motif analysis that reveals systematic prediction errors, thereby indicating potential ways of improving inference methods. The accuracy of network inference methods is evaluated using standard metrics such as precision-recall and receiver operating characteristic curves. We show how GNW can be used to assess the performance and identify the strengths and weaknesses of six inference methods. Furthermore, we used GNW to provide the international Dialogue for Reverse Engineering Assessments and Methods (DREAM) competition with three network inference challenges (DREAM3, DREAM4 and DREAM5). GNW is available at http://gnw.sourceforge.net along with its Java source code, user manual and supporting data. Supplementary data are available at Bioinformatics online. dario.floreano@epfl.ch.

  1. A network application for modeling a centrifugal compressor performance map

    Science.gov (United States)

    Nikiforov, A.; Popova, D.; Soldatova, K.

    2017-08-01

    The approximation of aerodynamic performance of a centrifugal compressor stage and vaneless diffuser by neural networks is presented. Advantages, difficulties and specific features of the method are described. An example of a neural network and its structure is shown. The performances in terms of efficiency, pressure ratio and work coefficient of 39 model stages within the range of flow coefficient from 0.01 to 0.08 were modeled with mean squared error 1.5 %. In addition, the loss and friction coefficients of vaneless diffusers of relative widths 0.014-0.10 are modeled with mean squared error 2.45 %.

  2. A multihop key agreement scheme for wireless ad hoc networks based on channel characteristics.

    Science.gov (United States)

    Hao, Zhuo; Zhong, Sheng; Yu, Nenghai

    2013-01-01

    A number of key agreement schemes based on wireless channel characteristics have been proposed recently. However, previous key agreement schemes require that two nodes which need to agree on a key are within the communication range of each other. Hence, they are not suitable for multihop wireless networks, in which nodes do not always have direct connections with each other. In this paper, we first propose a basic multihop key agreement scheme for wireless ad hoc networks. The proposed basic scheme is resistant to external eavesdroppers. Nevertheless, this basic scheme is not secure when there exist internal eavesdroppers or Man-in-the-Middle (MITM) adversaries. In order to cope with these adversaries, we propose an improved multihop key agreement scheme. We show that the improved scheme is secure against internal eavesdroppers and MITM adversaries in a single path. Both performance analysis and simulation results demonstrate that the improved scheme is efficient. Consequently, the improved key agreement scheme is suitable for multihop wireless ad hoc networks.

  3. Research on Harmonic Characteristics Influence for Distribution Network with Renewable Energy

    Directory of Open Access Journals (Sweden)

    Huang Wei

    2016-01-01

    Full Text Available In order to study the influence on harmonic characteristics of distribution network with renewable energy, a simplified model of distribution network is established to analyse theory while considering the influence of cable on the system capacitive current. Establishing an actual distribution network model by Digsilent to research the harmonic characteristics impact when photovoltaic power with PV incorporated the distribution network in a variety of different access , while using constant current source model as harmonic source model which often been used in engineering practices. The simulation results show that: optimizing the access location and dispersion of PV can decrease the waveform distortion levels in distribution network and a certain number of high-order harmonic will magnify by a specific grid structure, deteriorating the distribution network power quality.

  4. Identifying the relevant dependencies of the neural network response on characteristics of the input space

    CERN Multimedia

    CERN. Geneva

    2018-01-01

    This talk presents an approach to identify those characteristics of the neural network inputs that are most relevant for the response and therefore provides essential information to determine the systematic uncertainties.

  5. Evaluation of knowledge management performances in NULIFE network

    International Nuclear Information System (INIS)

    Nitoi, Mirela; Cojan, Mihai; Pavelescu, Margarit

    2009-01-01

    One of the objectives of Nuclear Plant Life Prediction (NULIFE) network is the identification of experts and resources which can be used in the future. The major challenge is to use these competent personnel in an efficient manner, in the network. The paper presents the necessity of developing the knowledge management strategy for networks of excellence, as the specific issues of NULIFE network. In order to highlight the progress during the project operating, the developed indicators of performance are specified. The developed questionnaires evaluate the quality of knowledge management (development, use and distribution of knowledge), type of knowledge which is considered important for organization (at present and in future) and the benefits of knowledge transfer (immediate and in perspective). The developed questionnaires permit along with the evaluation of others groups activities, an auto-evaluation for the activity of the group where the subject is involved. (authors)

  6. Error performance analysis in downlink cellular networks with interference management

    KAUST Repository

    Afify, Laila H.

    2015-05-01

    Modeling aggregate network interference in cellular networks has recently gained immense attention both in academia and industry. While stochastic geometry based models have succeeded to account for the cellular network geometry, they mostly abstract many important wireless communication system aspects (e.g., modulation techniques, signal recovery techniques). Recently, a novel stochastic geometry model, based on the Equivalent-in-Distribution (EiD) approach, succeeded to capture the aforementioned communication system aspects and extend the analysis to averaged error performance, however, on the expense of increasing the modeling complexity. Inspired by the EiD approach, the analysis developed in [1] takes into consideration the key system parameters, while providing a simple tractable analysis. In this paper, we extend this framework to study the effect of different interference management techniques in downlink cellular network. The accuracy of the proposed analysis is verified via Monte Carlo simulations.

  7. Fault-tolerance performance evaluation of fieldbus for NPCS network of KNGR

    International Nuclear Information System (INIS)

    Jung, Hyun Gi

    1999-02-01

    In contrast with conventional fieldbus researches which are focused merely on real time performance, this study aims to evaluate the real-time performance of the communication system including fault-tolerant mechanisms. Maintaining performance in presence of recoverable faults is very important because the communication network will be applied to next generation NPP(Nuclear Power Plant). In order to guarantee the performance of NPP communication network, the time characteristics of the target system in presence of recoverable fault should be investigated. If the time characteristics meet the requirements of the system, the faults will be recovered by fieldbus recovery mechanisms and the system will be safe. If the time characteristics can not meet the requirements, the faults in the fieldbus can propagate to system failure. In this study, for the purpose of investigating the time characteristics of fieldbus, the recoverable faults are classified and then the formulas which represent delays including recovery mechanisms and the simulation model are developed. In order to validate the proposed approach, the simulation model is applied to the Korea Next Generation Reactor (KNGR) NSSS Process Control System (NPCS). The results of the simulation provide reasonable delay characteristics of the fault cases with recovery mechanisms. Using the outcome of the simulation and the system requirements, we also can calculate the failure propagation probability from fieldbus to outer system

  8. On the network protocol performance evaluation for large scale communication system of nuclear plant

    International Nuclear Information System (INIS)

    Song, K. S.; Lee, T. H.; Kim, H. R.; Kim, D. H.; Ku, I. S.

    1998-01-01

    Computer technology has been dramatically advanced and it is now natural to apply digital network technology into nuclear plants. Communication architecture for nuclear plant defines the coordination of safety reactor control, balance of plant, subsystem utilities, and plant monitoring functions, and how they are connected and their user interface to guarantee plant performance and guarantee safety requirements. Therefore, to implement a digital network for control and monitoring systems of advanced nuclear plant needs systematic design and evaluation procedures because of responsive and hard real-time process characteristics of nuclear plant. In this paper, we evaluate several digital network protocols in terms of network delay, link failure effects to hard real-time requirements with full scale traffic

  9. Relationships between Isometric Force-Time Characteristics and Dynamic Performance

    Directory of Open Access Journals (Sweden)

    Thomas Dos’Santos

    2017-09-01

    Full Text Available The purpose of this study was to explore the relationships between isometric mid-thigh pull (IMTP force-time characteristics (peak force and time-specific force vales (100–250 ms and dynamic performance and compare dynamic performance between stronger and weaker athletes. Forty-three athletes from different sports (rowing, soccer, bicycle motocross, and hockey performed three trials of the squat jump (SJ, countermovement jump (CMJ, and IMTP, and performed a one repetition maximum power clean (PC. Reactive strength index modified (RSImod was also calculated from the CMJ. Statistically significant large correlations between IMTP force-time characteristics and PC (ρ = 0.569–0.674, p < 0.001, and moderate correlations between IMTP force-time characteristics (excluding force at 100 ms and RSImod (ρ = 0.389–0.449, p = 0.013–0.050 were observed. Only force at 250 ms demonstrated a statistically significant moderate correlation with CMJ height (ρ = 0.346, p = 0.016 and no statistically significant associations were observed between IMTP force-time characteristics and SJ height. Stronger athletes (top 10 demonstrated statistically significantly greater CMJ heights, RSImods, and PCs (p ≤ 0.004, g = 1.32–1.89 compared to weaker (bottom 10 athletes, but no differences in SJ height were observed (p = 0.871, g = 0.06. These findings highlight that the ability to apply rapidly high levels of force in short time intervals is integral for PC, CMJ height, and reactive strength.

  10. EXPERIMENTAL ANALYSIS OF THE CHARACTERISTIC PERFORMANCE OF STANDALONE PHOTOVOLTAIC SYSTEM

    OpenAIRE

    Birendra Kishore; Anirban Nandy*; O.P. Pandey

    2016-01-01

    This paper demonstrates an insight solar PV Stand Alone system which is a practical model with a halogen light source. At different situations the performance of solar PV cells are analyzed. The system produces power with depending on the change in halogen light intensity & temperature. A theoretical & experimental analysis of the PV cell can be achieved. In this paper the I-V & P-V characteristic of the solar photovoltaic cells with changes in temperature and isolation have been showed. With...

  11. Evaluating Flight Crew Performance by a Bayesian Network Model

    Directory of Open Access Journals (Sweden)

    Wei Chen

    2018-03-01

    Full Text Available Flight crew performance is of great significance in keeping flights safe and sound. When evaluating the crew performance, quantitative detailed behavior information may not be available. The present paper introduces the Bayesian Network to perform flight crew performance evaluation, which permits the utilization of multidisciplinary sources of objective and subjective information, despite sparse behavioral data. In this paper, the causal factors are selected based on the analysis of 484 aviation accidents caused by human factors. Then, a network termed Flight Crew Performance Model is constructed. The Delphi technique helps to gather subjective data as a supplement to objective data from accident reports. The conditional probabilities are elicited by the leaky noisy MAX model. Two ways of inference for the BN—probability prediction and probabilistic diagnosis are used and some interesting conclusions are drawn, which could provide data support to make interventions for human error management in aviation safety.

  12. Structure and Topology Dynamics of Hyper-Frequency Networks during Rest and Auditory Oddball Performance.

    Science.gov (United States)

    Müller, Viktor; Perdikis, Dionysios; von Oertzen, Timo; Sleimen-Malkoun, Rita; Jirsa, Viktor; Lindenberger, Ulman

    2016-01-01

    Resting-state and task-related recordings are characterized by oscillatory brain activity and widely distributed networks of synchronized oscillatory circuits. Electroencephalographic recordings (EEG) were used to assess network structure and network dynamics during resting state with eyes open and closed, and auditory oddball performance through phase synchronization between EEG channels. For this assessment, we constructed a hyper-frequency network (HFN) based on within- and cross-frequency coupling (WFC and CFC, respectively) at 10 oscillation frequencies ranging between 2 and 20 Hz. We found that CFC generally differentiates between task conditions better than WFC. CFC was the highest during resting state with eyes open. Using a graph-theoretical approach (GTA), we found that HFNs possess small-world network (SWN) topology with a slight tendency to random network characteristics. Moreover, analysis of the temporal fluctuations of HFNs revealed specific network topology dynamics (NTD), i.e., temporal changes of different graph-theoretical measures such as strength, clustering coefficient, characteristic path length (CPL), local, and global efficiency determined for HFNs at different time windows. The different topology metrics showed significant differences between conditions in the mean and standard deviation of these metrics both across time and nodes. In addition, using an artificial neural network approach, we found stimulus-related dynamics that varied across the different network topology metrics. We conclude that functional connectivity dynamics (FCD), or NTD, which was found using the HFN approach during rest and stimulus processing, reflects temporal and topological changes in the functional organization and reorganization of neuronal cell assemblies.

  13. Distributed dynamic simulations of networked control and building performance applications.

    Science.gov (United States)

    Yahiaoui, Azzedine

    2018-02-01

    The use of computer-based automation and control systems for smart sustainable buildings, often so-called Automated Buildings (ABs), has become an effective way to automatically control, optimize, and supervise a wide range of building performance applications over a network while achieving the minimum energy consumption possible, and in doing so generally refers to Building Automation and Control Systems (BACS) architecture. Instead of costly and time-consuming experiments, this paper focuses on using distributed dynamic simulations to analyze the real-time performance of network-based building control systems in ABs and improve the functions of the BACS technology. The paper also presents the development and design of a distributed dynamic simulation environment with the capability of representing the BACS architecture in simulation by run-time coupling two or more different software tools over a network. The application and capability of this new dynamic simulation environment are demonstrated by an experimental design in this paper.

  14. 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.

  15. Performance and Complexity of Tunable Sparse Network Coding with Gradual Growing Tuning Functions over Wireless Networks

    DEFF Research Database (Denmark)

    Garrido, Pablo; Sørensen, Chres Wiant; Roetter, Daniel Enrique Lucani

    2016-01-01

    Random Linear Network Coding (RLNC) has been shown to be a technique with several benefits, in particular when applied over wireless mesh networks, since it provides robustness against packet losses. On the other hand, Tunable Sparse Network Coding (TSNC) is a promising concept, which leverages...... a trade-off between computational complexity and goodput. An optimal density tuning function has not been found yet, due to the lack of a closed-form expression that links density, performance and computational cost. In addition, it would be difficult to implement, due to the feedback delay. In this work...

  16. The influence of passenger flow on the topology characteristics of urban rail transit networks

    Science.gov (United States)

    Hu, Yingyue; Chen, Feng; Chen, Peiwen; Tan, Yurong

    2017-05-01

    Current researches on the network characteristics of metro networks are generally carried out on topology networks without passenger flows running on it, thus more complex features of the networks with ridership loaded on it cannot be captured. In this study, we incorporated the load of metro networks, passenger volume, into the exploration of network features. Thus, the network can be examined in the context of operation, which is the ultimate purpose of the existence of a metro network. To this end, section load was selected as an edge weight to demonstrate the influence of ridership on the network, and a weighted calculation method for complex network indicators and robustness were proposed to capture the unique behaviors of a metro network with passengers flowing in it. The proposed method was applied on Beijing Subway. Firstly, the passenger volume in terms of daily origin and destination matrix was extracted from exhausted transit smart card data. Using the established approach and the matrix as weighting, common indicators of complex network including clustering coefficient, betweenness and degree were calculated, and network robustness were evaluated under potential attacks. The results were further compared to that of unweighted networks, and it suggests indicators of the network with consideration of passenger volumes differ from that without ridership to some extent, and networks tend to be more vulnerable than that without load on it. The significance sequence for the stations can be changed. By introducing passenger flow weighting, actual operation status of the network can be reflected more accurately. It is beneficial to determine the crucial stations and make precautionary measures for the entire network’s operation security.

  17. Study on the complex network characteristics of urban road system based on GIS

    Science.gov (United States)

    Gao, Zhonghua; Chen, Zhenjie; Liu, Yongxue; Huang, Kang

    2007-06-01

    Urban road system is the basic bone of urban transportation and one of the most important factors that influent and controls the urban configuration. In this paper, an approach of modeling, analyzing and optimizing urban road system is described based on complex network theory and GIS technology. The urban road system is studied on three focuses: building the urban road network, modeling the computational procedures based on urban road networks and analyzing the urban road system of Changzhou City as the study case. The conclusion is that the urban road network is a scale-free network with small-world characteristic, and there is still space for development of the whole network as a small-world network, also the key road crosses should be kept expedite.

  18. Characteristics of Social Network Gamers: Results of an Online Survey.

    Science.gov (United States)

    Geisel, Olga; Panneck, Patricia; Stickel, Anna; Schneider, Michael; Müller, Christian A

    2015-01-01

    Current research on Internet addiction (IA) reported moderate to high prevalence rates of IA and comorbid psychiatric symptoms in users of social networking sites (SNS) and online role-playing games. The aim of this study was to characterize adult users of an Internet multiplayer strategy game within a SNS. Therefore, we conducted an exploratory study using an online survey to assess sociodemographic variables, psychopathology, and the rate of IA in a sample of adult social network gamers by Young's Internet Addiction Test (IAT), the Toronto Alexithymia Scale (TAS-26), the Beck Depression Inventory-II (BDI-II), the Symptom Checklist-90-R (SCL-90-R), and the WHO Quality of Life-BREF (WHOQOL-BREF). All participants were listed gamers of "Combat Zone" in the SNS "Facebook." In this sample, 16.2% of the participants were categorized as subjects with IA and 19.5% fulfilled the criteria for alexithymia. Comparing study participants with and without IA, the IA group had significantly more subjects with alexithymia, reported more depressive symptoms, and showed poorer quality of life. These findings suggest that social network gaming might also be associated with maladaptive patterns of Internet use. Furthermore, a relationship between IA, alexithymia, and depressive symptoms was found that needs to be elucidated by future studies.

  19. 172 Networks, Micro Small Enterprises (MSE'S) and Performance ...

    African Journals Online (AJOL)

    User

    It is no doubt that the role of entrepreneurship in the emerging economies such like Kenya ... understand networking and small business performance as there is no single general ... solution for small firm development (Borg 1991, Donckels and Lambrecht. 1995 ..... Scandinavian Journal of Management , 31 (3/4), 83-99.

  20. The Influence of Social Networks on High School Students' Performance

    Science.gov (United States)

    Abu-Shanab, Emad; Al-Tarawneh, Heyam

    2015-01-01

    Social networks are becoming an integral part of people's lives. Students are spending much time on social media and are considered the largest category that uses such application. This study tries to explore the influence of social media use, and especially Facebook, on high school students' performance. The study used the GPA of students in four…

  1. Distributed dynamic simulations of networked control and building performance applications

    NARCIS (Netherlands)

    Yahiaoui, Azzedine

    2018-01-01

    The use of computer-based automation and control systems for smart sustainable buildings, often so-called Automated Buildings (ABs), has become an effective way to automatically control, optimize, and supervise a wide range of building performance applications over a network while achieving the

  2. Road safety performance indicators for the interurban road network.

    NARCIS (Netherlands)

    Yannis, G. Weijermars, W.A.M. Gitelman, V. Vis, M. Chazirisa, A. Papadimitriou, E. & Lima Azevedo, C.

    2013-01-01

    Various road safety performance indicators (SPIs) have been proposed for different road safety research areas, mainly as regards driver behaviour (e.g. seat belt use, alcohol, drugs, etc.) and vehicles (e.g. passive safety); however, no SPIs for the road network and design have been developed. The

  3. 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].

  4. Performance Analysis of RF-FSO Multi-Hop Networks

    KAUST Repository

    Makki, Behrooz; Svensson, Tommy; Brandt-Pearce, Maite; Alouini, Mohamed-Slim

    2017-01-01

    We study the performance of multi-hop networks composed of millimeter wave (MMW)-based radio frequency (RF) and free-space optical (FSO) links. The results are obtained in the cases with and without hybrid automatic repeat request (HARQ). Taking

  5. Improvement on the Performance of Canal Network and Method of ...

    African Journals Online (AJOL)

    This paper presents the required improvement on the performance of canal network and method of on-farm water application systems at Tunga-Kawo irrigation scheme, Wushishi, Niger state. The problems of poor delivery of water to the farmland were identified to include erosion of canal embarkment, lack of water ...

  6. Performance characteristics of solar air heater with surface mounted obstacles

    International Nuclear Information System (INIS)

    Bekele, Adisu; Mishra, Manish; Dutta, Sushanta

    2014-01-01

    Highlights: • Solar air heater with delta shaped obstacles have been studied. • Obstacle angle of incidence strongly affects the thermo-hydraulic performance. • Thermal performance of obstacle mounted collectors is superior to smooth collectors. • Thermo-hydraulic performance of the present SAH is higher than those in previous studies. - Abstract: The performance of conventional solar air heaters (SAHs) can be improved by providing obstacles on the heated wall (i.e. on the absorber plate). Experiments have been performed to collect heat transfer and flow-friction data from an air heater duct with delta-shaped obstacles mounted on the absorber surface and having an aspect ratio 6:1 resembling the conditions close to the solar air heaters. This study encompassed for the range of Reynolds number (Re) from 2100 to 30,000, relative obstacle height (e/H) from 0.25 to 0.75, relative obstacle longitudinal pitch (P l /e) from 3/2 to 11/2, relative obstacle transverse pitch (P t /b) from 1 to 7/3 and the angle of incidence (α) varied from 30° to 90°. The thermo-hydraulic performance characteristics of SAH have been compared with the previous published works and the optimum range of the geometries have been explored for the better performance of such air-heaters compared to the other designs of solar air heaters

  7. Model Of Emergency Department Nurse Performance Improvement Based on Association of Individual Characteristic, Organization Characteristic and Job Characteristic

    OpenAIRE

    Bogar, Maria Margaretha; Nursalam, Nursalam; Dewi, Yulis Setiya

    2017-01-01

    Introduction: Nursing care is integral part of health care and having important role in management of patient with emergency condition. The purpose of this research was to develop nurse performance improvement model based on individual, organization and job characteristics association in Emergency Department of RSUD dr TC Hillers Maumere. Method: This was an explanative survey by cross sectional approach held on July -August 2012. Respondents in this study were 22 nurses and 44 patients were ...

  8. Characteristic Length Scales in Fracture Networks: Hydraulic Connectivity through Periodic Hydraulic Tests

    Science.gov (United States)

    Becker, M.; Bour, O.; Le Borgne, T.; Longuevergne, L.; Lavenant, N.; Cole, M. C.; Guiheneuf, N.

    2017-12-01

    Determining hydraulic and transport connectivity in fractured bedrock has long been an important objective in contaminant hydrogeology, petroleum engineering, and geothermal operations. A persistent obstacle to making this determination is that the characteristic length scale is nearly impossible to determine in sparsely fractured networks. Both flow and transport occur through an unknown structure of interconnected fracture and/or fracture zones making the actual length that water or solutes travel undetermined. This poses difficulties for flow and transport models. For, example, hydraulic equations require a separation distance between pumping and observation well to determine hydraulic parameters. When wells pairs are close, the structure of the network can influence the interpretation of well separation and the flow dimension of the tested system. This issue is explored using hydraulic tests conducted in a shallow fractured crystalline rock. Periodic (oscillatory) slug tests were performed at the Ploemeur fractured rock test site located in Brittany, France. Hydraulic connectivity was examined between three zones in one well and four zones in another, located 6 m apart in map view. The wells are sufficiently close, however, that the tangential distance between the tested zones ranges between 6 and 30 m. Using standard periodic formulations of radial flow, estimates of storativity scale inversely with the square of the separation distance and hydraulic diffusivity directly with the square of the separation distance. Uncertainty in the connection paths between the two wells leads to an order of magnitude uncertainty in estimates of storativity and hydraulic diffusivity, although estimates of transmissivity are unaffected. The assumed flow dimension results in alternative estimates of hydraulic parameters. In general, one is faced with the prospect of assuming the hydraulic parameter and inverting the separation distance, or vice versa. Similar uncertainties exist

  9. EFFECTS OF SOCIAL NETWORKING SITES ON THE ACADEMIC PERFORMANCE OF THE FIRST YEAR BSED STUDENTS OF NAVAL STATE UNIVERSITY

    OpenAIRE

    Christopher Rotilles Vicera, Ed. D*

    2016-01-01

    This study aimed to determine the effects of social networking sites on the academic performance of the students as related to the socio-demographic characteristics, social networking site usage and social network addiction. As to the socio-demographic characteristics, the respondents' age ranged from 15-17 years old or 70% of the total number of respondents. A big proportion of 70% were females. Most of the respondents were single with 98%. Their family income ranged from P5,000-9,999 with 4...

  10. Evaluation of High-Performance Network Technologies for ITER

    Energy Technology Data Exchange (ETDEWEB)

    Zagar, K.; Kolaric, P.; Sabjan, R.; Zagar, A. [Cosylab d.d., Ljubljana (Slovenia); Hunt, S. [Alceli Hunt Beratung, Meisterschwanden (Switzerland)

    2009-07-01

    To facilitate fast feedback control of plasma, ITER's Control, Data Access and Communication system (CODAC) will need to provide a mechanism for hard real-time communication between its distributed nodes. In particular, four types of high-performance communication have been identified. Synchronous Databus Network (SDN) is to provide an ability to distribute parameters of plasma (estimated to about 5000 double-valued signals) across the system to allow for 1 ms control cycles. Event Distribution Network (EDN) and Time Communication Network (TCN) are to allow synchronization of node I/O operations to 10 ns. Finally, the Audio Video Network (AVN) is to provide sufficient bandwidth for streaming of surveillance and diagnostics video at a high resolution (1024*1024) and frame rate (30 Hz). In this article, we present some combinations of common off-the-shelf (COTS) technologies that allow the above requirements to be met. Also, we present the performances achieved in a practical (though small scale) technology demonstrator, which involved a real-time LINUS operating running on National Instruments' PXI platform, UDP communication implemented directly atop the Ethernet network adapter, CISCO switches, Micro Research Finland's timing and event solution, and GigE audio-video streaming. This document is composed of an abstract followed by the presentation transparencies. (authors)

  11. Evaluation of high-performance network technologies for ITER

    Energy Technology Data Exchange (ETDEWEB)

    Zagar, K., E-mail: klemen.zagar@cosylab.co [Cosylab d.d., 1000 Ljubljana (Slovenia); Hunt, S. [Alceli Hunt Beratung, 5616 Meisterschwanden (Switzerland); Kolaric, P.; Sabjan, R.; Zagar, A.; Dedic, J. [Cosylab d.d., 1000 Ljubljana (Slovenia)

    2010-07-15

    For the fast feedback plasma controllers, ITER's Control, Data Access and Communication system (CODAC) will need to provide a mechanism for hard real-time communication between its distributed nodes. In particular, the ITER CODAC team identified four types of high-performance communication applications. Synchronous Databus Network (SDN) is to provide an ability to distribute parameters of plasma (estimated to about 5000 double-valued signals) across the system to allow for 1 ms control cycles. Event Distribution Network (EDN) and Time Communication Network (TCN) are to allow synchronization of node I/O operations to 10 ns. Finally, the Audio-Video Network (AVN) is to provide sufficient bandwidth for streaming of surveillance and diagnostics video at a high resolution (1024 x 1024) and frame rate (30 Hz). In this article, we present some combinations of common-off-the-shelf (COTS) technologies that allow the above requirements to be met. Also, we present the performances achieved in a practical (though small scale) technology demonstrator, which involved a real-time Linux operating running on National Instruments' PXI platform, UDP communication implemented directly atop the Ethernet network adapter, CISCO switches, Micro Research Finland's timing and event solution, and GigE audio-video streaming.

  12. Evaluation of high-performance network technologies for ITER

    International Nuclear Information System (INIS)

    Zagar, K.; Hunt, S.; Kolaric, P.; Sabjan, R.; Zagar, A.; Dedic, J.

    2010-01-01

    For the fast feedback plasma controllers, ITER's Control, Data Access and Communication system (CODAC) will need to provide a mechanism for hard real-time communication between its distributed nodes. In particular, the ITER CODAC team identified four types of high-performance communication applications. Synchronous Databus Network (SDN) is to provide an ability to distribute parameters of plasma (estimated to about 5000 double-valued signals) across the system to allow for 1 ms control cycles. Event Distribution Network (EDN) and Time Communication Network (TCN) are to allow synchronization of node I/O operations to 10 ns. Finally, the Audio-Video Network (AVN) is to provide sufficient bandwidth for streaming of surveillance and diagnostics video at a high resolution (1024 x 1024) and frame rate (30 Hz). In this article, we present some combinations of common-off-the-shelf (COTS) technologies that allow the above requirements to be met. Also, we present the performances achieved in a practical (though small scale) technology demonstrator, which involved a real-time Linux operating running on National Instruments' PXI platform, UDP communication implemented directly atop the Ethernet network adapter, CISCO switches, Micro Research Finland's timing and event solution, and GigE audio-video streaming.

  13. The Impact of Social Networks on Students’ Performance

    OpenAIRE

    Jusuf Zekiri

    2016-01-01

    The objective of this study is to determine the impact of using social media and its impact on students’ performance and success. This research tries to identify the relationship between students’ use of social networks and their success in their studies. It tries also to find out whether time spent impacts students’ performance and success. Whether students use social media more for entertainment or for teaching and information sharing purposes. The paper uses a quantitative approach for col...

  14. Performance characteristics of a quantum Diesel refrigeration cycle

    International Nuclear Information System (INIS)

    He Jizhou; Wang Hao; Liu Sanqiu

    2009-01-01

    The Diesel refrigeration cycle using an ideal quantum gas as the working substance is called quantum Diesel refrigeration cycle, which is different from Carnot, Ericsson, Brayton, Otto and Stirling refrigeration cycles. For ideal quantum gases, a corrected equation of state, which considers the quantum behavior of gas particles, is used instead of the classical one. The purpose of this paper is to investigate the effect of quantum gas as the working substance on the performance of a quantum Diesel refrigeration cycle. It is found that coefficients of performance of the cycle are not affected by the quantum degeneracy of the working substance, which is the same as that of the classical Diesel refrigeration cycle. However, the refrigeration load is different from those of the classical Diesel refrigeration cycle. Lastly, the influence of the quantum degeneracy on the performance characteristics of the quantum Diesel refrigeration cycle operated in different temperature regions is discussed

  15. Performance and emission characteristics of double biodiesel blends with diesel

    Directory of Open Access Journals (Sweden)

    Kuthalingam Arun Balasubramanian

    2013-01-01

    Full Text Available Recent research on biodiesel focused on performance of single biodiesel and its blends with diesel. The present work aims to investigate the possibilities of the application of mixtures of two biodiesel and its blends with diesel as a fuel for diesel engines. The combinations of Pongamia pinnata biodiesel, Mustard oil biodiesel along with diesel (PMD and combinations of Cotton seed biodiesel, Pongamia pinnata biodiesel along with diesel (CPD are taken for the experimental analysis. Experiments are conducted using a single cylinder direct-injection diesel engine with different loads at rated 3000 rpm. The engine characteristics of the two sets of double biodiesel blends are compared. For the maximum load, the value of Specific Fuel consumption and thermal efficiency of CPD-1 blend (10:10:80 is close to the diesel values. CPD blends give better engine characteristics than PMD blends. The blends of CPD are suitable alternative fuel for diesel in stationary/agricultural diesel engines.

  16. Some performance characteristics of a fluidized bed heat recovery unit

    International Nuclear Information System (INIS)

    Militzer, J.; Basu, P.; Adaikkappan, N.

    1985-01-01

    The advantages of using fluidized bed heat recovery units with diesel engines are well documented. Two of those are: significantly less tube fouling and heat transfer coefficient four to five time higher than that of conventional shell and tube heat exchangers. The high concentration of soot in the exhaust gases of diesel engines make fouling a major concern in design of any kind of heat recovery unit. In the experiment a conventional fluidized bed heat exchanger was connected to the exhaust of a diesel engine mounted on a dynamometer. With this arrangement it was possible to test the heat recovery unit under a wide range of operating conditions. The main objective of this experiment was the determination of the performance characteristics of the heat recovery unit, especially with reference to its heat transfer and fouling characteristics. (author)

  17. Characteristics and Performance of Existing Load Disaggregation Technologies

    Energy Technology Data Exchange (ETDEWEB)

    Mayhorn, Ebony T. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Sullivan, Greg P. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Butner, Ryan S. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Hao, He [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Baechler, Michael C. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2015-04-10

    Non-intrusive load monitoring (NILM) or non-intrusive appliance load monitoring (NIALM) is an analytic approach to disaggregate building loads based on a single metering point. This advanced load monitoring and disaggregation technique has the potential to provide an alternative solution to high-priced traditional sub-metering and enable innovative approaches for energy conservation, energy efficiency, and demand response. However, since the inception of the concept in the 1980’s, evaluations of these technologies have focused on reporting performance accuracy without investigating sources of inaccuracies or fully understanding and articulating the meaning of the metrics used to quantify performance. As a result, the market for, as well as, advances in these technologies have been slowly maturing.To improve the market for these NILM technologies, there has to be confidence that the deployment will lead to benefits. In reality, every end-user and application that this technology may enable does not require the highest levels of performance accuracy to produce benefits. Also, there are other important characteristics that need to be considered, which may affect the appeal of NILM products to certain market targets (i.e. residential and commercial building consumers) and the suitability for particular applications. These characteristics include the following: 1) ease of use, the level of expertise/bandwidth required to properly use the product; 2) ease of installation, the level of expertise required to install along with hardware needs that impact product cost; and 3) ability to inform decisions and actions, whether the energy outputs received by end-users (e.g. third party applications, residential users, building operators, etc.) empower decisions and actions to be taken at time frames required for certain applications. Therefore, stakeholders, researchers, and other interested parties should be kept abreast of the evolving capabilities, uses, and characteristics

  18. State network approach to characteristics of financial crises

    Science.gov (United States)

    Qiu, Lu; Gu, Changgui; Xiao, Qin; Yang, Huijie; Wu, Guolin

    2018-02-01

    Extensive works have reported that a financial crisis can induce significant changes to topological structure of a stock network constructed with cross-correlations between stocks. But there are still some problems to be answered, such as what is the relationship between different crises in history and how to classify them? In the present work, we propose a new network-based solution to extract and display the relationships between the crises. The Dow Jones stock market is investigated as a typical example. The cross-correlation matrix between stocks is used to measure the state of stock market, called state matrix. All the states cluster into six sub-categories. A state network is constructed further to display the relationships between all the states, which contains a total of nine communities. It is found that three crises C , D and E (refer to the Lehman's bankruptcy in 2008, the Euro-zone and International Monetary Fund decide the first bailout for Greece in 2010, and the European sovereign debt crisis in 2011, respectively) belong to a specific sub-category and cluster in a single community. The mid-stage of C is closely linked with E, while the other stages with D. The other two crises A and B (refer to the financial crisis in Asia in 1997, and the burst of "dot-com bubble" in 2002, respectively) belong to another sub-category and gather in a corner of another single community. A and B are linked directly with C and D by two edges. By this way, we give a clear picture of the relationships between the crises.

  19. The establishment of heterogeneous networks in performative spaces

    DEFF Research Database (Denmark)

    Suenson, Valinka; Harder, Henrik

    2010-01-01

    This paper presents an empirical research combining the Actor Network Theory with a development of RFID (Radio Frequency Identification) technology for tracking indoor movement behavior. The aim of the paper is to disucss the value of RFID technology as a method for observing heterogeneous networks...... and architecture through this theoretical perspective, it highlights the importance of the user involvement in the performative spaces where materiality becomes an actant on equal terms with the users. This paper discusses the use of RFID technology for tracking indoor movenment behavior as a method for examining...

  20. Performance characteristics of CdTe drift ring detector

    Science.gov (United States)

    Alruhaili, A.; Sellin, P. J.; Lohstroh, A.; Veeramani, P.; Kazemi, S.; Veale, M. C.; Sawhney, K. J. S.; Kachkanov, V.

    2014-03-01

    CdTe and CdZnTe material is an excellent candidate for the fabrication of high energy X-ray spectroscopic detectors due to their good quantum efficiency and room temperature operation. The main material limitation is associated with the poor charge transport properties of holes. The motivation of this work is to investigate the performance characteristics of a detector fabricated with a drift ring geometry that is insensitive to the transport of holes. The performance of a prototype Ohmic CdTe drift ring detector fabricated by Acrorad with 3 drift rings is reported; measurements include room temperature current voltage characteristics (IV) and spectroscopic performance. The data shows that the energy resolution of the detector is limited by leakage current which is a combination of bulk and surface leakage currents. The energy resolution was studied as a function of incident X-ray position with an X-ray microbeam at the Diamond Light Source. Different ring biasing schemes were investigated and the results show that by increasing the lateral field (i.e. the bias gradient across the rings) the active area, evaluated by the detected count rate, increased significantly.

  1. PERFORMANCE CHARACTERISTIC MEMS-BASED IMUs FOR UAVs NAVIGATION

    Directory of Open Access Journals (Sweden)

    H. A. Mohamed

    2015-08-01

    Full Text Available Accurate 3D reconstruction has become essential for non-traditional mapping applications such as urban planning, mining industry, environmental monitoring, navigation, surveillance, pipeline inspection, infrastructure monitoring, landslide hazard analysis, indoor localization, and military simulation. The needs of these applications cannot be satisfied by traditional mapping, which is based on dedicated data acquisition systems designed for mapping purposes. Recent advances in hardware and software development have made it possible to conduct accurate 3D mapping without using costly and high-end data acquisition systems. Low-cost digital cameras, laser scanners, and navigation systems can provide accurate mapping if they are properly integrated at the hardware and software levels. Unmanned Aerial Vehicles (UAVs are emerging as a mobile mapping platform that can provide additional economical and practical advantages. However, such economical and practical requirements need navigation systems that can provide uninterrupted navigation solution. Hence, testing the performance characteristics of Micro-Electro-Mechanical Systems (MEMS or low cost navigation sensors for various UAV applications is important research. This work focuses on studying the performance characteristics under different manoeuvres using inertial measurements integrated with single point positioning, Real-Time-Kinematic (RTK, and additional navigational aiding sensors. Furthermore, the performance of the inertial sensors is tested during Global Positioning System (GPS signal outage.

  2. Performance Characteristic Mems-Based IMUs for UAVs Navigation

    Science.gov (United States)

    Mohamed, H. A.; Hansen, J. M.; Elhabiby, M. M.; El-Sheimy, N.; Sesay, A. B.

    2015-08-01

    Accurate 3D reconstruction has become essential for non-traditional mapping applications such as urban planning, mining industry, environmental monitoring, navigation, surveillance, pipeline inspection, infrastructure monitoring, landslide hazard analysis, indoor localization, and military simulation. The needs of these applications cannot be satisfied by traditional mapping, which is based on dedicated data acquisition systems designed for mapping purposes. Recent advances in hardware and software development have made it possible to conduct accurate 3D mapping without using costly and high-end data acquisition systems. Low-cost digital cameras, laser scanners, and navigation systems can provide accurate mapping if they are properly integrated at the hardware and software levels. Unmanned Aerial Vehicles (UAVs) are emerging as a mobile mapping platform that can provide additional economical and practical advantages. However, such economical and practical requirements need navigation systems that can provide uninterrupted navigation solution. Hence, testing the performance characteristics of Micro-Electro-Mechanical Systems (MEMS) or low cost navigation sensors for various UAV applications is important research. This work focuses on studying the performance characteristics under different manoeuvres using inertial measurements integrated with single point positioning, Real-Time-Kinematic (RTK), and additional navigational aiding sensors. Furthermore, the performance of the inertial sensors is tested during Global Positioning System (GPS) signal outage.

  3. Performance and emissions characteristics of biodiesel from soybean oil

    Energy Technology Data Exchange (ETDEWEB)

    Canakci, M. [Kocaeli University, Izmit (Turkey). Faculty of Technical Education

    2005-07-15

    Biodiesel is an alternative diesel fuel that can be produced from renewable feedstocks such as vegetable oils, waste frying oils, and animal fats. It is an oxygenated, non-toxic, sulphur-free, biodegradable, and renewable fuel. Many engine manufacturers have included this fuel in their warranties since it can be used in diesel engines without significant modification. However, the fuel properties such as cetane number, heat of combustion, specific gravity, and kinematic viscosity affect the combustion, engine performance and emission characteristics. In this study, the engine performance and emissions characteristics of two different petroleum diesel fuels (No. 1 and No. 2 diesel fuels) and biodiesel from soybean oil and its 20 per cent blends with No. 2 diesel fuel were compared. The results showed that the engine performance of the neat biodiesel and its blend was similar to that of No. 2 diesel fuel with nearly the same brake fuel conversion efficiency, and slightly higher fuel consumption. CO{sub 2} emission for the biodiesel was slightly higher than for the No. 2 diesel fuel. Compared with diesel fuels, biodiesel produced lower exhaust emissions, except NO{sub x}. (author)

  4. Environmental investment and firm performance: A network approach

    International Nuclear Information System (INIS)

    Bostian, Moriah; Färe, Rolf; Grosskopf, Shawna; Lundgren, Tommy

    2016-01-01

    This study examines the role of investment in environmental production practices for both environmental performance and energy efficiency over time. We employ a network DEA approach that links successive production technologies through intertemporal investment decisions with a period by period estimation. This allows us to estimate energy efficiency and environmental performance separately, as well as productivity change and its associated decompositions into efficiency change and technology change. Incorporating a network model also allows us to account for both short-term environmental management practices and long-term environmental investments in each of our productivity measures. We apply this framework to a panel of detailed plant-level production data for Swedish manufacturing firms covering the years 2002–2008. - Highlights: • We use a network DEA model to account for intertemporal environmental investment decisionsin measures of firm productivity. • We apply our network technology model to a panel of firms in Sweden's pulp and paperindustry for the years 2002 - 2008. • We model environmental investments and expenditures separately from other productionoriented inputs. • We find evidence of positive relationships between energy efficiency, environmental performance, and firm productivity.

  5. Breeder design for enhanced performance and safety characteristics

    International Nuclear Information System (INIS)

    Fischer, G.J.; Atefi, B.; Yang, J.W.; Galperin, A.; Segev, M.

    1980-01-01

    A fast breeder reactor design has been created which offers a considerably extended fuel cycle and excellent performance characteristics. An example of a core designed to operate on a ten-year fuel cycle is described in some detail. Use of metal fuel along with a moderator such as beryllium oxide dispersed throughout the core provides both design flexibility and safety advantages such as a strong Doppler feedback and limited sodium void reactivity gain. Local power variations are small for the entire cycle; control requirements are also modest, and fuel cycle costs are low

  6. Performance characteristics of the DIII-D advanced divertor cryopump

    International Nuclear Information System (INIS)

    Menon, M.M.; Maingi, R.; Wade, M.R.; Baxi, C.B.; Campbell, G.L.; Holtrop, K.L.; Hyatt, A.W.; Laughon, G.J.; Makariou, C.C.; Mahdavi, M.A.; Reis, E.E.; Schaffer, M.J.; Schaubel, K.M.; Scoville, J.T.; Smith, J.P.; Stambaugh, R.D.

    1993-10-01

    A cryocondensation pump, cooled by forced flow of two-phase helium, has been installed for particle exhaust from the divertor region of the DIII-D tokamak. The Inconel pumping surface is of coaxial geometry, 25.4 mm in outer diameter and 11.65 m in length. Because of the tokamak environment, the pump is designed to perform under relatively high pulsed heat loads (300 Wm -2 ). Results of measurements made on the pumping characteristics for D 2 , H 2 , and Ar are discussed

  7. Enhanced memory performance thanks to neural network assortativity

    International Nuclear Information System (INIS)

    Franciscis, S. de; Johnson, S.; Torres, J. J.

    2011-01-01

    The behaviour of many complex dynamical systems has been found to depend crucially on the structure of the underlying networks of interactions. An intriguing feature of empirical networks is their assortativity--i.e., the extent to which the degrees of neighbouring nodes are correlated. However, until very recently it was difficult to take this property into account analytically, most work being exclusively numerical. We get round this problem by considering ensembles of equally correlated graphs and apply this novel technique to the case of attractor neural networks. Assortativity turns out to be a key feature for memory performance in these systems - so much so that for sufficiently correlated topologies the critical temperature diverges. We predict that artificial and biological neural systems could significantly enhance their robustness to noise by developing positive correlations.

  8. Topology and computational performance of attractor neural networks

    International Nuclear Information System (INIS)

    McGraw, Patrick N.; Menzinger, Michael

    2003-01-01

    To explore the relation between network structure and function, we studied the computational performance of Hopfield-type attractor neural nets with regular lattice, random, small-world, and scale-free topologies. The random configuration is the most efficient for storage and retrieval of patterns by the network as a whole. However, in the scale-free case retrieval errors are not distributed uniformly among the nodes. The portion of a pattern encoded by the subset of highly connected nodes is more robust and efficiently recognized than the rest of the pattern. The scale-free network thus achieves a very strong partial recognition. The implications of these findings for brain function and social dynamics are suggestive

  9. Value networks in manufacturing sustainability and performance excellence

    CERN Document Server

    Uusitalo, Teuvo

    2017-01-01

    This book highlights innovative solutions together with various techniques and methods that can help support the manufacturing sector to excel in economic, social, and environmental terms in networked business environments. The book also furthers understanding of sustainable manufacturing from the perspective of value creation in manufacturing networks, by capitalizing on the outcomes of the European ‘Sustainable Value Creation in Manufacturing Networks’ project. New dynamics and uncertainties in modern markets call for innovative solutions in the global manufacturing sector. While the manufacturing sector is traditionally driven by technology, it also requires other managerial and organizational solutions in terms of network governance, business models, sustainable solution development for products and services, performance management portals, etc., which can provide major competitive advantages for companies. At the same time, the manufacturing industry is subject to a change process, where business net...

  10. Performance Modeling of Communication Networks with Markov Chains

    CERN Document Server

    Mo, Jeonghoon

    2010-01-01

    This book is an introduction to Markov chain modeling with applications to communication networks. It begins with a general introduction to performance modeling in Chapter 1 where we introduce different performance models. We then introduce basic ideas of Markov chain modeling: Markov property, discrete time Markov chain (DTMe and continuous time Markov chain (CTMe. We also discuss how to find the steady state distributions from these Markov chains and how they can be used to compute the system performance metric. The solution methodologies include a balance equation technique, limiting probab

  11. The social support and social network characteristics of smokers in methadone maintenance treatment.

    Science.gov (United States)

    de Dios, Marcel Alejandro; Stanton, Cassandra A; Caviness, Celeste M; Niaura, Raymond; Stein, Michael

    2013-01-01

    Previous studies have shown social support and social network variables to be important factors in smoking cessation treatment. Tobacco use is highly prevalent among individuals in methadone maintenance treatment (MMT). However, smoking cessation treatment outcomes in this vulnerable subpopulation have been poor and social support and social network variables may contribute. The current study examined the social support and social network characteristics of 151 MMT smokers involved in a randomized clinical trial of smoking cessation treatments. Participants were 50% women and 78% Caucasian. A high proportion (57%) of MMT smokers had spouses or partners who smoke and over two-thirds of households (68.5%) included at least one smoker. Our sample was characterized by relatively small social networks, but high levels of general social support and quitting support. The number of cigarettes per day was found to be positively associated with the number of smokers in the social network (r = .239, p social support and social networks of smokers in MMT.

  12. Research on robust optimization of emergency logistics network considering the time dependence characteristic

    Science.gov (United States)

    WANG, Qingrong; ZHU, Changfeng; LI, Ying; ZHANG, Zhengkun

    2017-06-01

    Considering the time dependence of emergency logistic network and complexity of the environment that the network exists in, in this paper the time dependent network optimization theory and robust discrete optimization theory are combined, and the emergency logistics dynamic network optimization model with characteristics of robustness is built to maximize the timeliness of emergency logistics. On this basis, considering the complexity of dynamic network and the time dependence of edge weight, an improved ant colony algorithm is proposed to realize the coupling of the optimization algorithm and the network time dependence and robustness. Finally, a case study has been carried out in order to testify validity of this robustness optimization model and its algorithm, and the value of different regulation factors was analyzed considering the importance of the value of the control factor in solving the optimal path. Analysis results show that this model and its algorithm above-mentioned have good timeliness and strong robustness.

  13. Investigating the effect of communication characteristics on crew performance under the simulated emergency condition of nuclear power plants

    International Nuclear Information System (INIS)

    Park, Jinkyun; Jung, Wondea; Yang, Joon-Eon

    2012-01-01

    It is well known that the safety of large process control systems could be significantly affected by the communication characteristics of crews that have a responsibility for their operations. Accordingly, many researchers have spent huge amount of effort to grasp the relationship between the characteristics of crew communications and the associated crew performance. Unfortunately, in the case of nuclear power plants (NPPs), it seems that most of existing studies have tried to identify the relationship between the characteristics of crew communications and the associated crew performance using empirical observations without a firm technical underpinning. For these reasons, Park suggested a novel framework that is able to represent the characteristics of crew communications based on social network analysis (SNA) metrics. In order to confirm the appropriateness of the suggested framework, in this study, the characteristics of crew communications that are gathered from the simulated emergency condition of NPPs are additionally compared with the associated crew performance data. As a consequence, it is observed that there are significant relationships between communication characteristics and the associated crew performance. Therefore, it is reasonable to expect that the characteristics of crew communications can be properly grasped using the suggested framework. - Highlights: ► Communication data of MCR operating crews are collected from a simulated emergency condition. ► Communication characteristics are represented by the associated SNA metrics. ► Identified communication characteristics are compared with the results of existing studies. ► SNA metrics are meaningful for explaining the characteristics of crew communications.

  14. Design and implementation of a high performance network security processor

    Science.gov (United States)

    Wang, Haixin; Bai, Guoqiang; Chen, Hongyi

    2010-03-01

    The last few years have seen many significant progresses in the field of application-specific processors. One example is network security processors (NSPs) that perform various cryptographic operations specified by network security protocols and help to offload the computation intensive burdens from network processors (NPs). This article presents a high performance NSP system architecture implementation intended for both internet protocol security (IPSec) and secure socket layer (SSL) protocol acceleration, which are widely employed in virtual private network (VPN) and e-commerce applications. The efficient dual one-way pipelined data transfer skeleton and optimised integration scheme of the heterogenous parallel crypto engine arrays lead to a Gbps rate NSP, which is programmable with domain specific descriptor-based instructions. The descriptor-based control flow fragments large data packets and distributes them to the crypto engine arrays, which fully utilises the parallel computation resources and improves the overall system data throughput. A prototyping platform for this NSP design is implemented with a Xilinx XC3S5000 based FPGA chip set. Results show that the design gives a peak throughput for the IPSec ESP tunnel mode of 2.85 Gbps with over 2100 full SSL handshakes per second at a clock rate of 95 MHz.

  15. Performance Analysis of Cluster Formation in Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Edgar Romo Montiel

    2017-12-01

    Full Text Available Clustered-based wireless sensor networks have been extensively used in the literature in order to achieve considerable energy consumption reductions. However, two aspects of such systems have been largely overlooked. Namely, the transmission probability used during the cluster formation phase and the way in which cluster heads are selected. Both of these issues have an important impact on the performance of the system. For the former, it is common to consider that sensor nodes in a clustered-based Wireless Sensor Network (WSN use a fixed transmission probability to send control data in order to build the clusters. However, due to the highly variable conditions experienced by these networks, a fixed transmission probability may lead to extra energy consumption. In view of this, three different transmission probability strategies are studied: optimal, fixed and adaptive. In this context, we also investigate cluster head selection schemes, specifically, we consider two intelligent schemes based on the fuzzy C-means and k-medoids algorithms and a random selection with no intelligence. We show that the use of intelligent schemes greatly improves the performance of the system, but their use entails higher complexity and selection delay. The main performance metrics considered in this work are energy consumption, successful transmission probability and cluster formation latency. As an additional feature of this work, we study the effect of errors in the wireless channel and the impact on the performance of the system under the different transmission probability schemes.

  16. Performance Analysis of Cluster Formation in Wireless Sensor Networks.

    Science.gov (United States)

    Montiel, Edgar Romo; Rivero-Angeles, Mario E; Rubino, Gerardo; Molina-Lozano, Heron; Menchaca-Mendez, Rolando; Menchaca-Mendez, Ricardo

    2017-12-13

    Clustered-based wireless sensor networks have been extensively used in the literature in order to achieve considerable energy consumption reductions. However, two aspects of such systems have been largely overlooked. Namely, the transmission probability used during the cluster formation phase and the way in which cluster heads are selected. Both of these issues have an important impact on the performance of the system. For the former, it is common to consider that sensor nodes in a clustered-based Wireless Sensor Network (WSN) use a fixed transmission probability to send control data in order to build the clusters. However, due to the highly variable conditions experienced by these networks, a fixed transmission probability may lead to extra energy consumption. In view of this, three different transmission probability strategies are studied: optimal, fixed and adaptive. In this context, we also investigate cluster head selection schemes, specifically, we consider two intelligent schemes based on the fuzzy C-means and k-medoids algorithms and a random selection with no intelligence. We show that the use of intelligent schemes greatly improves the performance of the system, but their use entails higher complexity and selection delay. The main performance metrics considered in this work are energy consumption, successful transmission probability and cluster formation latency. As an additional feature of this work, we study the effect of errors in the wireless channel and the impact on the performance of the system under the different transmission probability schemes.

  17. A diagnosis model for early Tourette syndrome children based on brain structural network characteristics

    Science.gov (United States)

    Wen, Hongwei; Liu, Yue; Wang, Jieqiong; Zhang, Jishui; Peng, Yun; He, Huiguang

    2016-03-01

    Tourette syndrome (TS) is a childhood-onset neurobehavioral disorder characterized by the presence of multiple motor and vocal tics. Tic generation has been linked to disturbed networks of brain areas involved in planning, controlling and execution of action. The aim of our work is to select topological characteristics of structural network which were most efficient for estimating the classification models to identify early TS children. Here we employed the diffusion tensor imaging (DTI) and deterministic tractography to construct the structural networks of 44 TS children and 48 age and gender matched healthy children. We calculated four different connection matrices (fiber number, mean FA, averaged fiber length weighted and binary matrices) and then applied graph theoretical methods to extract the regional nodal characteristics of structural network. For each weighted or binary network, nodal degree, nodal efficiency and nodal betweenness were selected as features. Support Vector Machine Recursive Feature Extraction (SVM-RFE) algorithm was used to estimate the best feature subset for classification. The accuracy of 88.26% evaluated by a nested cross validation was achieved on combing best feature subset of each network characteristic. The identified discriminative brain nodes mostly located in the basal ganglia and frontal cortico-cortical networks involved in TS children which was associated with tic severity. Our study holds promise for early identification and predicting prognosis of TS children.

  18. Integration and the performance of healthcare networks: do integration strategies enhance efficiency, profitability, and image?

    Directory of Open Access Journals (Sweden)

    Thomas T.H. Wan

    2001-06-01

    Full Text Available Purpose: This study examines the integration effects on efficiency and financial viability of the top 100 integrated healthcare networks (IHNs in the United States. Theory: A contingency- strategic theory is used to identify the relationship of IHNs' performance to their structural and operational characteristics and integration strategies. Methods: The lists of the top 100 IHNs ranked in two years, 1998 and 1999, by the SMG Marketing Group were merged to create a database for the study. Multiple indicators were used to examine the relationship between IHNs' characteristics and their performance in efficiency and financial viability. A path analytical model was developed and validated by the Mplus statistical program. Factors influencing the top 100 IHNs' images, represented by attaining ranking among the top 100 in two consecutive years, were analysed. Results and conclusion: No positive associations were found between integration and network performance in efficiency or profits. Longitudinal data are needed to investigate the effect of integration on healthcare networks' financial performance.

  19. Board Characteristics and Firm Performance: Evidence from Indonesia

    Directory of Open Access Journals (Sweden)

    Athalia Ariati Hidayat

    2015-12-01

    Full Text Available This research examines the effect of board characteristics (comprising in different sized proportions: family commissioners, family directors, independent commissioners, ex-government officer commissioners, and board of commissioners size to firm performance. Using fixed-effects data panel regression, this research investigates 293 firms listed on the Indonesian Stock Exchange during 2008-2012. Firm performance is proxied by market measure (Tobin’s Q and accounting measure (ROA. The findings of this research suggest that the proportion of family commissioners and family directors have positive impact only to Tobin’s Q value, while the proportion of independent directors can increase both Tobin’s Q and ROA. On the other hand, this research finds that the proportion of ex-government officers in the board gives no impact to firm performance. This research also finds that the board size has U-shaped non-linear relationship with firm performance as proxied by Tobin’s Q and ROA.

  20. Firm performance: The role of CEOs' emotional and cognitive characteristics

    Directory of Open Access Journals (Sweden)

    Kleanthis K. Katsaros

    2015-08-01

    Full Text Available The paper examines the relationships between CEOs’ personal traits, emotions, attitudes and tolerance of ambiguity; and subsequently, the influence of CEOs’ ambiguity tolerance in firms' performance. Design/methodology/approach – Survey data were collected from 256 ICT firms established in Greece. Their CEOs completed questionnaires examining TOA, personal traits, emotions and attitudes in the workplace. Principal components analysis and ordinary least-squares regressions were used to explore the hypotheses of the paper. Findings – Three factors characterize CEOs' emotions, namely pleasure, dominance and arousal; two factors their involvement, namely importance and interest; and, respectively, one their emotional intelligence namely, empathy/handling relationships. Further, locus of control; importance; arousal; empathy/handling relationships and interest affect decisively CEOs' tolerance of ambiguity, which in turn, seems to influence positively firms' performance. Research limitations/implications – Further research is required in Greek ICT industry regarding the influence of CEOs' emotional and cognitive attributes in organizations' financial performance. Likewise, this research should be expanded to other industries. Originality/value – The originality of this study lies in the finding that emotional and cognitive characteristics affect CEOs' TOA, which, in turn, influences significantly firms' performance. Another significant contributing factor is that the study is carried out in Greece, where few studies have been conducted in this area.

  1. A Performance Evaluation Model for Mobile Ad Hoc Networks and Sensor Networks

    Directory of Open Access Journals (Sweden)

    Heng LUO

    2014-03-01

    Full Text Available Potential applications in areas such as military sites and disaster relief fields that are characterized by absence of prefixed infrastructure justify the development of mobile ad hoc networks (MANETs and wireless sensor networks (WSNs. However, unfavorable wireless links and dynamic topology are still challenging, leading to the proposal of a collection of routing protocols for MANETs and WSNs. Nevertheless the performance of algorithms may vary with deployment scenario due to the application dependent philosophy behind algorithms. In this paper, the performance evaluation problem for MANETs and WSNs is investigated and a novel performance ranking model, termed AHP-SAW, is proposed. For simplicity but without loss of generality, the performance of two routing protocols DSDV and DSR are studies based on which ranking results are provided. Extensive simulations show that an overall 37.2 %, at most, gain may be achieved based on the AHP-SAW model.

  2. Fault diagnosis and performance evaluation for high current LIA based on radial basis function neural network

    International Nuclear Information System (INIS)

    Yang Xinglin; Wang Huacen; Chen Nan; Dai Wenhua; Li Jin

    2006-01-01

    High current linear induction accelerator (LIA) is a complicated experimental physics device. It is difficult to evaluate and predict its performance. this paper presents a method which combines wavelet packet transform and radial basis function (RBF) neural network to build fault diagnosis and performance evaluation in order to improve reliability of high current LIA. The signal characteristics vectors which are extracted based on energy parameters of wavelet packet transform can well present the temporal and steady features of pulsed power signal, and reduce data dimensions effectively. The fault diagnosis system for accelerating cell and the trend classification system for the beam current based on RBF networks can perform fault diagnosis and evaluation, and provide predictive information for precise maintenance of high current LIA. (authors)

  3. Information-Theoretic Performance Analysis of Sensor Networks via Markov Modeling of Time Series Data.

    Science.gov (United States)

    Li, Yue; Jha, Devesh K; Ray, Asok; Wettergren, Thomas A; Yue Li; Jha, Devesh K; Ray, Asok; Wettergren, Thomas A; Wettergren, Thomas A; Li, Yue; Ray, Asok; Jha, Devesh K

    2018-06-01

    This paper presents information-theoretic performance analysis of passive sensor networks for detection of moving targets. The proposed method falls largely under the category of data-level information fusion in sensor networks. To this end, a measure of information contribution for sensors is formulated in a symbolic dynamics framework. The network information state is approximately represented as the largest principal component of the time series collected across the network. To quantify each sensor's contribution for generation of the information content, Markov machine models as well as x-Markov (pronounced as cross-Markov) machine models, conditioned on the network information state, are constructed; the difference between the conditional entropies of these machines is then treated as an approximate measure of information contribution by the respective sensors. The x-Markov models represent the conditional temporal statistics given the network information state. The proposed method has been validated on experimental data collected from a local area network of passive sensors for target detection, where the statistical characteristics of environmental disturbances are similar to those of the target signal in the sense of time scale and texture. A distinctive feature of the proposed algorithm is that the network decisions are independent of the behavior and identity of the individual sensors, which is desirable from computational perspectives. Results are presented to demonstrate the proposed method's efficacy to correctly identify the presence of a target with very low false-alarm rates. The performance of the underlying algorithm is compared with that of a recent data-driven, feature-level information fusion algorithm. It is shown that the proposed algorithm outperforms the other algorithm.

  4. An evaluation of current high-performance networks

    Energy Technology Data Exchange (ETDEWEB)

    Bell, Christian; Bonachea, Dan; Cote, Yannick; Duell, Jason; Hargrove, Paul; Husbands, Parry; Iancu, Costin; Welcome, Michael; Yelick, Katherine

    2003-01-25

    High-end supercomputers are increasingly built out of commodity components, and lack tight integration between the processor and network. This often results in inefficiencies in the communication subsystem, such as high software overheads and/or message latencies. In this paper we use a set of microbenchmarks to quantify the cost of this commoditization, measuring software overhead, latency, and bandwidth on five contemporary supercomputing networks. We compare the performance of the ubiquitous MPI layer to that of lower-level communication layers, and quantify the advantages of the latter for small message performance. We also provide data on the potential for various communication-related optimizations, such as overlapping communication with computation or other communication. Finally, we determine the minimum size needed for a message to be considered 'large' (i.e., bandwidth-bound) on these platforms, and provide historical data on the software overheads of a number of supercomputers over the past decade.

  5. Performance Analysis of TDMA Protocol in a Femtocell Network

    Directory of Open Access Journals (Sweden)

    Wanod Kumar

    2014-07-01

    Full Text Available In this paper, we evaluate the performance of TDMA (Time Division Multiple Access protocol using queuing theory in a femtocell network. The fair use of wireless channel among the users of network is carried out using TDMA protocol. The arrival of data packets from M communicating nodes becomes multiple Poisson process. The time slots of TDMA protocol represent c servers to communicate data packets coming from communicating nodes to the input of FAP (Femtocell Access Point. The service time of each server (time slot is exponentially distributed. This complete communication scenario using TDMA protocol is modeled using M/M/c queue. The performance of the protocol is evaluated in terms of mean number in system, average system delay and utilization for varying traffic intensity

  6. The Gain of Performance of Optical WDM Networks

    Directory of Open Access Journals (Sweden)

    Miroslav Bahleda

    2008-01-01

    Full Text Available We study the blocking probability and performance of single-fiber and multifiber optical networks with wavelength division multiplexing (WDM. We extend the well-known analytical blocking probability model by Barry and Humblet to the general model, which is proposed for both single-fiber and multifiber network paths with any kind of wavelength conversion (no, limited, or full wavelength conversion and for uniform and nonuniform link loads. We investigate the effect of the link load, wavelength conversion degree, and the number of wavelengths, fibers, and hops on blocking probability. We also extend the definition of the gain of wavelength conversion by Barry and Humblet to the gain of performance, which is fully general. Thanks to this definition and implementation of our model, we compare different WDM node architectures and present interesting results.

  7. Real-Time Communications in Autonomic Networks: System Implementation and Performance Evaluation

    Directory of Open Access Journals (Sweden)

    C. Tselios

    2012-01-01

    Full Text Available This paper describes the design and prototype implementation of a communication platform aiming to provide voice and video communication in a distributed networking environment. Performance considerations and network characteristics have also been taken into account in order to provide the set of properties dictated by the sensitive nature and the real-time characteristics of the targeted application scenarios. The proposed system has been evaluated both by experimental means as well as subjective tests taken by an extensive number of users. The results show that the proposed platform operates seamlessly in two hops, while in the four hops scenario, audio and video are delivered with marginal distortion. The conducted survey indicates that the user experience in terms of Quality of Service has obtained higher scores in the scenario with the two hops.

  8. Using a Bayesian network to predict barrier island geomorphologic characteristics

    Science.gov (United States)

    Gutierrez, Ben; Plant, Nathaniel G.; Thieler, E. Robert; Turecek, Aaron

    2015-01-01

    Quantifying geomorphic variability of coastal environments is important for understanding and describing the vulnerability of coastal topography, infrastructure, and ecosystems to future storms and sea level rise. Here we use a Bayesian network (BN) to test the importance of multiple interactions between barrier island geomorphic variables. This approach models complex interactions and handles uncertainty, which is intrinsic to future sea level rise, storminess, or anthropogenic processes (e.g., beach nourishment and other forms of coastal management). The BN was developed and tested at Assateague Island, Maryland/Virginia, USA, a barrier island with sufficient geomorphic and temporal variability to evaluate our approach. We tested the ability to predict dune height, beach width, and beach height variables using inputs that included longer-term, larger-scale, or external variables (historical shoreline change rates, distances to inlets, barrier width, mean barrier elevation, and anthropogenic modification). Data sets from three different years spanning nearly a decade sampled substantial temporal variability and serve as a proxy for analysis of future conditions. We show that distinct geomorphic conditions are associated with different long-term shoreline change rates and that the most skillful predictions of dune height, beach width, and beach height depend on including multiple input variables simultaneously. The predictive relationships are robust to variations in the amount of input data and to variations in model complexity. The resulting model can be used to evaluate scenarios related to coastal management plans and/or future scenarios where shoreline change rates may differ from those observed historically.

  9. Effects of Network Performance on Smartphone User Behavior

    OpenAIRE

    Örblom, Markus

    2015-01-01

    While the relation between smartphone user behavior and contextual factors have been explored in previous research, the mobile networks’ influence on the smartphone user behavior is largely unknown. Through statistical analysis of a data set collected globally from ˜ 1000 users by an Android app called Ericsson Apps, this study investigates how the users’ app choices and app usage depend on the network performance. The results show, for instance, that the choice of app depends strongly on the...

  10. Data Driven Performance Evaluation of Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Antonio A. F. Loureiro

    2010-03-01

    Full Text Available Wireless Sensor Networks are presented as devices for signal sampling and reconstruction. Within this framework, the qualitative and quantitative influence of (i signal granularity, (ii spatial distribution of sensors, (iii sensors clustering, and (iv signal reconstruction procedure are assessed. This is done by defining an error metric and performing a Monte Carlo experiment. It is shown that all these factors have significant impact on the quality of the reconstructed signal. The extent of such impact is quantitatively assessed.

  11. Performance analysis of Cognitive Pilot Channel in wireless Heterogeneous networks

    OpenAIRE

    Hussein, Tahseen Ali

    2009-01-01

    This thesis aims to investigate and analyze the performance of the Cognitive Pilot Channel (CPC) in heterogeneous network. The thesis uses simulation to simulate the environment and the scenarios and by using this simulation, the analysis is done. First task this thesis carrying is the validation the simulation results with the numerical results. This is done by introducing a single cell scenario and validates the results out of this scenario with the numerical calculation. Ana...

  12. Performance evaluation of coherent Ising machines against classical neural networks

    Science.gov (United States)

    Haribara, Yoshitaka; Ishikawa, Hitoshi; Utsunomiya, Shoko; Aihara, Kazuyuki; Yamamoto, Yoshihisa

    2017-12-01

    The coherent Ising machine is expected to find a near-optimal solution in various combinatorial optimization problems, which has been experimentally confirmed with optical parametric oscillators and a field programmable gate array circuit. The similar mathematical models were proposed three decades ago by Hopfield et al in the context of classical neural networks. In this article, we compare the computational performance of both models.

  13. High-Performance Neural Networks for Visual Object Classification

    OpenAIRE

    Cireşan, Dan C.; Meier, Ueli; Masci, Jonathan; Gambardella, Luca M.; Schmidhuber, Jürgen

    2011-01-01

    We present a fast, fully parameterizable GPU implementation of Convolutional Neural Network variants. Our feature extractors are neither carefully designed nor pre-wired, but rather learned in a supervised way. Our deep hierarchical architectures achieve the best published results on benchmarks for object classification (NORB, CIFAR10) and handwritten digit recognition (MNIST), with error rates of 2.53%, 19.51%, 0.35%, respectively. Deep nets trained by simple back-propagation perform better ...

  14. Depth-dependent flow and pressure characteristics in cortical microvascular networks.

    Directory of Open Access Journals (Sweden)

    Franca Schmid

    2017-02-01

    Full Text Available A better knowledge of the flow and pressure distribution in realistic microvascular networks is needed for improving our understanding of neurovascular coupling mechanisms and the related measurement techniques. Here, numerical simulations with discrete tracking of red blood cells (RBCs are performed in three realistic microvascular networks from the mouse cerebral cortex. Our analysis is based on trajectories of individual RBCs and focuses on layer-specific flow phenomena until a cortical depth of 1 mm. The individual RBC trajectories reveal that in the capillary bed RBCs preferentially move in plane. Hence, the capillary flow field shows laminar patterns and a layer-specific analysis is valid. We demonstrate that for RBCs entering the capillary bed close to the cortical surface (< 400 μm the largest pressure drop takes place in the capillaries (37%, while for deeper regions arterioles are responsible for 61% of the total pressure drop. Further flow characteristics, such as capillary transit time or RBC velocity, also vary significantly over cortical depth. Comparison of purely topological characteristics with flow-based ones shows that a combined interpretation of topology and flow is indispensable. Our results provide evidence that it is crucial to consider layer-specific differences for all investigations related to the flow and pressure distribution in the cortical vasculature. These findings support the hypothesis that for an efficient oxygen up-regulation at least two regulation mechanisms must be playing hand in hand, namely cerebral blood flow increase and microvascular flow homogenization. However, the contribution of both regulation mechanisms to oxygen up-regulation likely varies over depth.

  15. Passive and Active Monitoring on a High Performance Research Network

    International Nuclear Information System (INIS)

    Matthews, Warren

    2001-01-01

    The bold network challenges described in ''Internet End-to-end Performance Monitoring for the High Energy and Nuclear Physics Community'' presented at PAM 2000 have been tackled by the intrepid administrators and engineers providing the network services. After less than a year, the BaBar collaboration has collected almost 100 million particle collision events in a database approaching 165TB (Tera=10 12 ). Around 20TB has been exported via the Internet to the BaBar regional center at IN2P3 in Lyon, France, for processing and around 40 TB of simulated events have been imported to SLAC from Lawrence Livermore National Laboratory (LLNL). An unforseen challenge has arisen due to recent events and highlighted security concerns at DoE funded labs. New rules and regulations suggest it is only a matter of time before many active performance measurements may not be possible between many sites. Yet, at the same time, the importance of understanding every aspect of the network and eradicating packet loss for high throughput data transfers has become apparent. Work at SLAC to employ passive monitoring using netflow and OC3MON is underway and techniques to supplement and possibly replace the active measurements are being considered. This paper will detail the special needs and traffic characterization of a remarkable research project, and how the networking hurdles have been resolved (or not) to achieve the required high data throughput. Results from active and passive measurements will be compared, and methods for achieving high throughput and the effect on the network will be assessed along with tools that directly measure throughput and applications used to actually transfer data

  16. Passive and Active Monitoring on a High Performance Research Network.

    Energy Technology Data Exchange (ETDEWEB)

    Matthews, Warren

    2001-05-01

    The bold network challenges described in ''Internet End-to-end Performance Monitoring for the High Energy and Nuclear Physics Community'' presented at PAM 2000 have been tackled by the intrepid administrators and engineers providing the network services. After less than a year, the BaBar collaboration has collected almost 100 million particle collision events in a database approaching 165TB (Tera=10{sup 12}). Around 20TB has been exported via the Internet to the BaBar regional center at IN2P3 in Lyon, France, for processing and around 40 TB of simulated events have been imported to SLAC from Lawrence Livermore National Laboratory (LLNL). An unforseen challenge has arisen due to recent events and highlighted security concerns at DoE funded labs. New rules and regulations suggest it is only a matter of time before many active performance measurements may not be possible between many sites. Yet, at the same time, the importance of understanding every aspect of the network and eradicating packet loss for high throughput data transfers has become apparent. Work at SLAC to employ passive monitoring using netflow and OC3MON is underway and techniques to supplement and possibly replace the active measurements are being considered. This paper will detail the special needs and traffic characterization of a remarkable research project, and how the networking hurdles have been resolved (or not!) to achieve the required high data throughput. Results from active and passive measurements will be compared, and methods for achieving high throughput and the effect on the network will be assessed along with tools that directly measure throughput and applications used to actually transfer data.

  17. ‘Down-Stream’ Network Characteristics, Broker Functions and New Product Development Success

    DEFF Research Database (Denmark)

    Smed, Marie; Salomo, Søren; Li, Ying

    2011-01-01

    that small entrepreneurial start up company’s supply knowledge to network alliances with well-established and financially strong companies. However, in the later stages of development the main influence of external partnerships is described as financial support and joining distribution efforts, rather than...... of later stage product development tasks. While networks can be characterized by a number of measures like breadth, density, and structural characteristics, more recent developments in network and alliance management need to be specifically accounted for. In particular, it is observed that companies today...... richness to our conceptual model, we further include qualitative case studies supporting grounded theory building. In sum, this paper contributes to the literature by the following: (1) We develop a systematic overview over network characteristics shown to have impact for new product development. (2) We...

  18. Dismissing Attachment Characteristics Dynamically Modulate Brain Networks Subserving Social Aversion

    NARCIS (Netherlands)

    Krause, Anna Linda; Borchardt, Viola; Li, Meng; van Tol, Marie-Jose; Demenescu, Liliana Ramona; Strauss, Bernhard; Kirchmanny, Helmut; Buchheim, Anna; Metzger, Coraline D.; Nolte, Tobias; Walter, Martin

    2016-01-01

    Attachment patterns influence actions, thoughts and feeling through a person's "inner working model". Speech charged with attachment-dependent content was proposed to modulate the activation of cognitive-emotional schemata in listeners. We performed a 7 Tesla rest-task-rest functional magnetic

  19. Drive Control Scheme of Electric Power Assisted Wheelchair Based on Neural Network Learning of Human Wheelchair Operation Characteristics

    Science.gov (United States)

    Tanohata, Naoki; Seki, Hirokazu

    This paper describes a novel drive control scheme of electric power assisted wheelchairs based on neural network learning of human wheelchair operation characteristics. “Electric power assisted wheelchair” which enhances the drive force of the operator by employing electric motors is expected to be widely used as a mobility support system for elderly and disabled people. However, some handicapped people with paralysis of the muscles of one side of the body cannot maneuver the wheelchair as desired because of the difference in the right and left input force. Therefore, this study proposes a neural network learning system of such human wheelchair operation characteristics and a drive control scheme with variable distribution and assistance ratios. Some driving experiments will be performed to confirm the effectiveness of the proposed control system.

  20. The Impact of Social Networks on Students’ Performance

    Directory of Open Access Journals (Sweden)

    Jusuf Zekiri

    2016-11-01

    Full Text Available The objective of this study is to determine the impact of using social media and its impact on students’ performance and success. This research tries to identify the relationship between students’ use of social networks and their success in their studies. It tries also to find out whether time spent impacts students’ performance and success. Whether students use social media more for entertainment or for teaching and information sharing purposes. The paper uses a quantitative approach for collecting the primary data. The data was collected by surveying 255 respondents from South East European University. The data analyses were done by SPSS so" ware program. Cronbach alpha is used for testing the validity and reliability of variables used in this study. The hypotheses were tested using One Simple T-test. The obtained empirical results show that a great number of students are aware of advantages and disadvantages by the social media. Thus, due to a great percent of times spent on social networking activities, the performance and the success of students suffer setbacks which could lead to a poor performance and they might fail to create a balance between the social media and academic activities. Furthermore, it is about their addiction, the loss of time leading to consequences in their academic development, and they are also influenced to a great extent negatively by the social networking sites, because their attention is focused on chatting and music while their academic activities are neglected. Finally, based on the results of survey, we can conclude that impact of social media on the academic performance of students should focus more on the positive side than on the negative side to achieve balance. Hence, creating more pages for research and academic activities will enable students to improve their performance, thereby avoiding a distraction which leads to deviation from their academic work.

  1. Performance benefits and limitations of a camera network

    Science.gov (United States)

    Carr, Peter; Thomas, Paul J.; Hornsey, Richard

    2005-06-01

    Visual information is of vital significance to both animals and artificial systems. The majority of mammals rely on two images, each with a resolution of 107-108 'pixels' per image. At the other extreme are insect eyes where the field of view is segmented into 103-105 images, each comprising effectively one pixel/image. The great majority of artificial imaging systems lie nearer to the mammalian characteristics in this parameter space, although electronic compound eyes have been developed in this laboratory and elsewhere. If the definition of a vision system is expanded to include networks or swarms of sensor elements, then schools of fish, flocks of birds and ant or termite colonies occupy a region where the number of images and the pixels/image may be comparable. A useful system might then have 105 imagers, each with about 104-105 pixels. Artificial analogs to these situations include sensor webs, smart dust and co-ordinated robot clusters. As an extreme example, we might consider the collective vision system represented by the imminent existence of ~109 cellular telephones, each with a one-megapixel camera. Unoccupied regions in this resolution-segmentation parameter space suggest opportunities for innovative artificial sensor network systems. Essential for the full exploitation of these opportunities is the availability of custom CMOS image sensor chips whose characteristics can be tailored to the application. Key attributes of such a chip set might include integrated image processing and control, low cost, and low power. This paper compares selected experimentally determined system specifications for an inward-looking array of 12 cameras with the aid of a camera-network model developed to explore the tradeoff between camera resolution and the number of cameras.

  2. Performance of monitoring networks estimated from a Gaussian plume model

    International Nuclear Information System (INIS)

    Seebregts, A.J.; Hienen, J.F.A.

    1990-10-01

    In support of the ECN study on monitoring strategies after nuclear accidents, the present report describes the analysis of the performance of a monitoring network in a square grid. This network is used to estimate the distribution of the deposition pattern after a release of radioactivity into the atmosphere. The analysis is based upon a single release, a constant wind direction and an atmospheric dispersion according to a simplified Gaussian plume model. A technique is introduced to estimate the parameters in this Gaussian model based upon measurements at specific monitoring locations and linear regression, although this model is intrinsically non-linear. With these estimated parameters and the Gaussian model the distribution of the contamination due to deposition can be estimated. To investigate the relation between the network and the accuracy of the estimates for the deposition, deposition data have been generated by the Gaussian model, including a measurement error by a Monte Carlo simulation and this procedure has been repeated for several grid sizes, dispersion conditions, number of measurements per location, and errors per single measurement. The present technique has also been applied for the mesh sizes of two networks in the Netherlands, viz. the Landelijk Meetnet Radioaciviteit (National Measurement Network on Radioactivity, mesh size approx. 35 km) and the proposed Landelijk Meetnet Nucleaire Incidenten (National Measurement Network on Nuclear Incidents, mesh size approx. 15 km). The results show accuracies of 11 and 7 percent, respectively, if monitoring locations are used more than 10 km away from the postulated accident site. These figures are based upon 3 measurements per location and a dispersion during neutral weather with a wind velocity of 4 m/s. For stable weather conditions and low wind velocities, i.e. a small plume, the calculated accuracies are at least a factor 1.5 worse.The present type of analysis makes a cost-benefit approach to the

  3. Exploration of artificial neural network [ANN] to predict the electrochemical characteristics of lithium-ion cells

    Energy Technology Data Exchange (ETDEWEB)

    Parthiban, Thirumalai; Ravi, R.; Kalaiselvi, N. [Central Electrochemical Research Institute (CECRI), Karaikudi 630006 (India)

    2007-12-31

    CoO anode, as an alternate to the carbonaceous anodes of lithium-ion cells has been prepared and investigated for electrochemical charge-discharge characteristics for about 50 cycles. Artificial neural networks (ANNs), which are useful in estimating battery performance, has been deployed for the first time to forecast and to verify the charge-discharge behavior of lithium-ion cells containing CoO anode for a total of 50 cycles. In this novel approach, ANN that has one input layer with one neuron corresponding to one input variable, viz., cycles [charge-discharge cycles] and a hidden layer consisting of three neurons to produce their outputs to the output layer through a sigmoid function has been selected for the present investigation. The output layer consists of two neurons, representing the charge and discharge capacity, whose activation function is also the sigmoid transfer function. In this ever first attempt to exploit ANN as an effective theoretical tool to understand the charge-discharge characteristics of lithium-ion cells, an excellent agreement between the calculated and observed capacity values was found with CoO anodes with the best fit values corresponding to an error factor of <1%, which is the highlight of the present study. (author)

  4. Social Network Characteristics and Daily Smoking among Young Adults in Sweden

    Directory of Open Access Journals (Sweden)

    Mikael Rostila

    2013-11-01

    Full Text Available A large number of studies have shown that friends’ smoking behavior is strongly associated with an individual’s own risk for smoking. However, few studies have examined whether other features of social networks, independently or conjointly with friends’ smoking behavior, may influence the risk for smoking. Because it is characterized by the growing importance of friendship networks, the transition from adolescence to young adulthood may constitute a particularly relevant period on which to focus our investigation of network influences on smoking behavior. The aim of this study was therefore to examine the consequences of peer smoking as well as other network characteristics (friends’ other health behaviors, relationship content, and structural aspects of the network on the risk for smoking among young adults. The data was based on a cross-sectional survey of Swedish 19-year-olds carried out in 2009 (n = 5,695 with a response rate of 51.6%. Logistic regression was the primary method of analysis. The results show that having a large percentage of smokers in one’s network was by far the most important risk factor for daily smoking. The risk of daily smoking was 21.20 (CI 14.24. 31.54 if 76%–100% of the network members smoked. Having a high percentage of physically active friends was inversely associated with daily smoking. The risk of smoking was 0.65 (CI 0.42. 1.00 if 76%–100% of the network members were physically active. No main associations between the other network characteristics (relationship content and structural aspects of the network and smoking were found. However, there was an interaction between the percentage of smokers in the network and relationship content (i.e., trust, relationship quality and propensity to discuss problems: positive relationship content in combination with peer smoking may increase the risk of smoking. Women with a high percentage of smokers in their networks were also at higher risk of daily

  5. Performance evaluation of distributed wavelength assignment in WDM optical networks

    Science.gov (United States)

    Hashiguchi, Tomohiro; Wang, Xi; Morikawa, Hiroyuki; Aoyama, Tomonori

    2004-04-01

    In WDM wavelength routed networks, prior to a data transfer, a call setup procedure is required to reserve a wavelength path between the source-destination node pairs. A distributed approach to a connection setup can achieve a very high speed, while improving the reliability and reducing the implementation cost of the networks. However, along with many advantages, several major challenges have been posed by the distributed scheme in how the management and allocation of wavelength could be efficiently carried out. In this thesis, we apply a distributed wavelength assignment algorithm named priority based wavelength assignment (PWA) that was originally proposed for the use in burst switched optical networks to the problem of reserving wavelengths of path reservation protocols in the distributed control optical networks. Instead of assigning wavelengths randomly, this approach lets each node select the "safest" wavelengths based on the information of wavelength utilization history, thus unnecessary future contention is prevented. The simulation results presented in this paper show that the proposed protocol can enhance the performance of the system without introducing any apparent drawbacks.

  6. Road safety performance indicators for the interurban road network.

    Science.gov (United States)

    Yannis, George; Weijermars, Wendy; Gitelman, Victoria; Vis, Martijn; Chaziris, Antonis; Papadimitriou, Eleonora; Azevedo, Carlos Lima

    2013-11-01

    Various road safety performance indicators (SPIs) have been proposed for different road safety research areas, mainly as regards driver behaviour (e.g. seat belt use, alcohol, drugs, etc.) and vehicles (e.g. passive safety); however, no SPIs for the road network and design have been developed. The objective of this research is the development of an SPI for the road network, to be used as a benchmark for cross-region comparisons. The developed SPI essentially makes a comparison of the existing road network to the theoretically required one, defined as one which meets some minimum requirements with respect to road safety. This paper presents a theoretical concept for the determination of this SPI as well as a translation of this theory into a practical method. Also, the method is applied in a number of pilot countries namely the Netherlands, Portugal, Greece and Israel. The results show that the SPI could be efficiently calculated in all countries, despite some differences in the data sources. In general, the calculated overall SPI scores were realistic and ranged from 81 to 94%, with the exception of Greece where the SPI was relatively lower (67%). However, the SPI should be considered as a first attempt to determine the safety level of the road network. The proposed method has some limitations and could be further improved. The paper presents directions for further research to further develop the SPI. Copyright © 2012 Elsevier Ltd. All rights reserved.

  7. Distributed utility technology cost, performance, and environmental characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Wan, Y; Adelman, S

    1995-06-01

    Distributed Utility (DU) is an emerging concept in which modular generation and storage technologies sited near customer loads in distribution systems and specifically targeted demand-side management programs are used to supplement conventional central station generation plants to meet customer energy service needs. Research has shown that implementation of the DU concept could provide substantial benefits to utilities. This report summarizes the cost, performance, and environmental and siting characteristics of existing and emerging modular generation and storage technologies that are applicable under the DU concept. It is intended to be a practical reference guide for utility planners and engineers seeking information on DU technology options. This work was funded by the Office of Utility Technologies of the US Department of Energy.

  8. Performance characteristics of a continuous-flow fluidic pump

    International Nuclear Information System (INIS)

    Robinson, S.M.; Counce, R.M.; Smith, G.V.

    1987-01-01

    The fluidic pump is a type of positive-displacement pump in which basic fluid mechanics phenomena are utilized to eliminate valves and other moving parts that are exposed to the fluid being transferred. The version described in this article is powered by gas pressure serving as gas pistons and is virtually maintenance-free. It utilizes two displacement vessels and is designed to produce a steady and continuous liquid flow. This type of pump may be very useful for the transfer of radioactive or hazardous liquids where mechanical maintenance may be difficult or exposure of personnel to the fluid is undesirable. This paper presents experimental and model-predicted characteristics of such systems. The effects of several geometric parameters and operating conditions on the performance of the pump are briefly discussed

  9. Modeling Nanoscale FinFET Performance by a Neural Network Method

    Directory of Open Access Journals (Sweden)

    Jin He

    2017-07-01

    Full Text Available This paper presents a neural network method to model nanometer FinFET performance. The principle of this method is firstly introduced and its application in modeling DC and conductance characteristics of nanoscale FinFET transistor is demonstrated in detail. It is shown that this method does not need parameter extraction routine while its prediction of the transistor performance has a small relative error within 1 % compared with measured data, thus this new method is as accurate as the physics based surface potential model.

  10. Independent and Interactive Effects of Neighborhood Disadvantage and Social Network Characteristics on Problem Drinking after Treatment.

    Science.gov (United States)

    Mericle, Amy A; Kaskutas, Lee A; Polcin, Doug L; Karriker-Jaffe, Katherine J

    2018-01-01

    Socioecological approaches to public health problems like addiction emphasize the importance of person-environment interactions. Neighborhood and social network characteristics may influence the likelihood of relapse among individuals in recovery, but these factors have been understudied, particularly with respect to conceptualizing social network characteristics as moderators of neighborhood disadvantage. Drawing from a larger prospective study of individuals recruited from outpatient treatment (N=451) and interviewed 1, 3, 5, and 7 years later, the aim of this study was to examine the independent and interactive effects of neighborhood and social network characteristics on continued problem drinking after treatment. Models using generalized estimating equations controlling for demographic and other risk factors found the number of heavy drinkers in one's network increases risk of relapse, with the effects being significantly stronger among those living in disadvantaged neighborhoods than among those in non-disadvantaged neighborhoods. No independent effects were found for neighborhood disadvantage or for the number of network members supporting reduced drinking. Future research is needed to examine potential protective factors in neighborhoods which may offset socioeconomic disadvantage as well as to investigate the functions that network members serve in helping to improve long-term treatment outcomes.

  11. Roasted sesame hulls improve broiler performance without affecting carcass characteristics

    Directory of Open Access Journals (Sweden)

    Kamel Z. Mahmoud

    2015-09-01

    Full Text Available An experiment was conducted to evaluate the effect of using graded levels of roasted sesame hulls (RSH on growth performance and meat quality characteristics in broiler chickens. A total of 360 day-old Lohmann chicks were randomly allocated into 24 floor pens and raised over 42 days. One of four dietary treatments was assigned to each group of six pens in a completely randomized fashion. The chicks in the control group were fed a corn-soybean based diet (RSH-0, while the chicks in treatments two, three, and four were fed graded levels of RSH at 4% (RSH-4, 8% (RSH-8, and 12% (RSH-12, respectively. Diets were formulated to meet broiler chicks’ requirements according to the National Research Council for both starter and finisher rations. The results showed that RSH inclusion increased (P<0.05 feed intake and final body weight without adversely affecting the feed conversion ratio. Broiler chicks fed RSH-12 had heavier (P<0.05 breast and leg cuts compared to the control-fed group with no change to their chemical composition. Water holding capacity (WHC, cooking loss (CL, and shear force (SF reported similar results in all dietary groups. The chemical composition of both thigh and breast cuts was not affected by the RSH. After one day of thawing, colour coordinates of breast cuts behaved similarly in all dietary groups. The results of this study suggest that the addition of RSH to broiler diets up to 12% improves their growth performance; nevertheless, carcass characteristics and meat quality showed no alterations compared to the control-fed group.

  12. Structural Modeling and Characteristics Analysis of Flow Interaction Networks in the Internet

    International Nuclear Information System (INIS)

    Wu Xiao-Yu; Gu Ren-Tao; Pan Zhuo-Ya; Jin Wei-Qi; Ji Yue-Feng

    2015-01-01

    Applying network duality and elastic mechanics, we investigate the interactions among Internet flows by constructing a weighted undirected network, where the vertices and the edges represent the flows and the mutual dependence between flows, respectively. Based on the obtained flow interaction network, we find the existence of ‘super flow’ in the Internet, indicating that some flows have a great impact on a huge number of other flows; moreover, one flow can spread its influence to another through a limited quantity of flows (less than 5 in the experimental simulations), which shows strong small-world characteristics like the social network. To reflect the flow interactions in the physical network congestion evaluation, the ‘congestion coefficient’ is proposed as a new metric which shows a finer observation on congestion than the conventional one. (paper)

  13. SON for LTE-WLAN access network selection : design and performance

    NARCIS (Netherlands)

    Willemen, P.; Laselva, D.; Wang, Y.; Kovács, I.; Djapic, R.; Moerman, I.

    2016-01-01

    Mobile network operators (MNOs) are deploying carrier-grade Wireless Local Area Network (WLAN) as an important complementary system to cellular networks. Access network selection (ANS) between cellular and WLAN is an essential component to improve network performance and user quality-of-service

  14. OPTIMAL CONFIGURATION OF A COMMAND AND CONTROL NETWORK: BALANCING PERFORMANCE AND RECONFIGURATION CONSTRAINTS

    Energy Technology Data Exchange (ETDEWEB)

    L. DOWELL

    1999-08-01

    The optimization of the configuration of communications and control networks is important for assuring the reliability and performance of the networks. This paper presents techniques for determining the optimal configuration for such a network in the presence of communication and connectivity constraints. reconfiguration to restore connectivity to a data-fusion network following the failure of a network component.

  15. Performance of WLAN RSS-based SON for LTE/WLAN access network selection

    NARCIS (Netherlands)

    Wang, Y.; Djapic, R.; Bergström, A.; Kovács, I.Z.; Laselva, D.; Spaey, K.; Sas, B.

    2014-01-01

    Mobile Network Operators (MNOs) are integrating carrier-grade Wireless Local Area Network (WLAN) to cellular networks to improve network performance and user experience. Access network selection (ANS) between cellular and WLAN plays a key role in the integration. Given the complexity of

  16. Network DEA: an application to analysis of academic performance

    Science.gov (United States)

    Saniee Monfared, Mohammad Ali; Safi, Mahsa

    2013-05-01

    As governmental subsidies to universities are declining in recent years, sustaining excellence in academic performance and more efficient use of resources have become important issues for university stakeholders. To assess the academic performances and the utilization of the resources, two important issues need to be addressed, i.e., a capable methodology and a set of good performance indicators as we consider in this paper. In this paper, we propose a set of performance indicators to enable efficiency analysis of academic activities and apply a novel network DEA structure to account for subfunctional efficiencies such as teaching quality, research productivity, as well as the overall efficiency. We tested our approach on the efficiency analysis of academic colleges at Alzahra University in Iran.

  17. Performance Evaluation Of Macro amp Micro Mobility In HMIP Networks

    Directory of Open Access Journals (Sweden)

    Osama Ali Abdelgadir

    2015-08-01

    Full Text Available Abstract Changing the location of mobile node during transmission or receiving of data always caused changing of the address of the mobile node which results in packet loss as well as delay in time taken to locate the new address of the Mobile Node therefore delay of data receiving is caused this problem was known as micro-mobility issue. To resolve this problem and ascurrently mobile IP is the most promising solution for mobility management in the Internet. Several IP micro mobility approaches have been proposed to enhance the performance of mobile IP which supports quality of service minimum packet loss limited handoff delay and scalability and power conservation but they are not scalable for macro mobility. A practical solution would therefore require integration of mobile IP and micro mobility protocols where mobile IP handles macro mobility and HMIP cellular IP HAWAII handles micro mobility. In this paper an integrated mobility management protocol for IP based wireless networks is proposed and analyzed.HIERARCHICAL MICRO MOBILITY PROTOCOL is used. To identify the impact of micro-mobility in IP based Wireless Network to implement selected micro-mobility model of Hierarchal Micro Mobility Protocol in network simulator and for more analysis and measurements results and for the purpose of performance comparison between both Macro and Micro mobility Protocol Management.. Simulation results presented in this paper are based on ns 2

  18. High Performance Data mining by Genetic Neural Network

    Directory of Open Access Journals (Sweden)

    Dadmehr Rahbari

    2013-10-01

    Full Text Available Data mining in computer science is the process of discovering interesting and useful patterns and relationships in large volumes of data. Most methods for mining problems is based on artificial intelligence algorithms. Neural network optimization based on three basic parameters topology, weights and the learning rate is a powerful method. We introduce optimal method for solving this problem. In this paper genetic algorithm with mutation and crossover operators change the network structure and optimized that. Dataset used for our work is stroke disease with twenty features that optimized number of that achieved by new hybrid algorithm. Result of this work is very well incomparison with other similar method. Low present of error show that our method is our new approach to efficient, high-performance data mining problems is introduced.

  19. Anti-correlations in the degree distribution increase stimulus detection performance in noisy spiking neural networks.

    Science.gov (United States)

    Martens, Marijn B; Houweling, Arthur R; E Tiesinga, Paul H

    2017-02-01

    Neuronal circuits in the rodent barrel cortex are characterized by stable low firing rates. However, recent experiments show that short spike trains elicited by electrical stimulation in single neurons can induce behavioral responses. Hence, the underlying neural networks provide stability against internal fluctuations in the firing rate, while simultaneously making the circuits sensitive to small external perturbations. Here we studied whether stability and sensitivity are affected by the connectivity structure in recurrently connected spiking networks. We found that anti-correlation between the number of afferent (in-degree) and efferent (out-degree) synaptic connections of neurons increases stability against pathological bursting, relative to networks where the degrees were either positively correlated or uncorrelated. In the stable network state, stimulation of a few cells could lead to a detectable change in the firing rate. To quantify the ability of networks to detect the stimulation, we used a receiver operating characteristic (ROC) analysis. For a given level of background noise, networks with anti-correlated degrees displayed the lowest false positive rates, and consequently had the highest stimulus detection performance. We propose that anti-correlation in the degree distribution may be a computational strategy employed by sensory cortices to increase the detectability of external stimuli. We show that networks with anti-correlated degrees can in principle be formed by applying learning rules comprised of a combination of spike-timing dependent plasticity, homeostatic plasticity and pruning to networks with uncorrelated degrees. To test our prediction we suggest a novel experimental method to estimate correlations in the degree distribution.

  20. Performance characteristics of counter flow wet cooling towers

    International Nuclear Information System (INIS)

    Khan, Jameel-Ur-Rehman; Yaqub, M.; Zubair, Syed M.

    2003-01-01

    Cooling towers are one of the biggest heat and mass transfer devices that are in widespread use. In this paper, we use a detailed model of counter flow wet cooling towers in investigating the performance characteristics. The validity of the model is checked by experimental data reported in the literature. The thermal performance of the cooling towers is clearly explained in terms of varying air and water temperatures, as well as the driving potential for convection and evaporation heat transfer, along the height of the tower. The relative contribution of each mode of heat transfer rate to the total heat transfer rate in the cooling tower is established. It is demonstrated with an example problem that the predominant mode of heat transfer is evaporation. For example, evaporation contributes about 62.5% of the total rate of heat transfer at the bottom of the tower and almost 90% at the top of the tower. The variation of air and water temperatures along the height of the tower (process line) is explained on psychometric charts

  1. Transonic Performance Characteristics of Several Jet Noise Suppressors

    Science.gov (United States)

    Schmeer, James W.; Salters, Leland B., Jr.; Cassetti, Marlowe D.

    1960-01-01

    An investigation of the transonic performance characteristics of several noise-suppressor configurations has been conducted in the Langley 16-foot transonic tunnel. The models were tested statically and over a Mach number range from 0.70 to 1.05 at an angle of attack of 0 deg. The primary jet total-pressure ratio was varied from 1.0 (jet off) to about 4.5. The effect of secondary air flow on the performance of two of the configurations was investigated. A hydrogen peroxide turbojet-engine simulator was used to supply the hot-jet exhaust. An 8-lobe afterbody with centerbody, short shroud, and secondary air had the highest thrust-minus-drag coefficients of the six noise-suppressor configurations tested. The 12-tube and 12-lobe afterbodies had the lowest internal losses. The presence of an ejector shroud partially shields the external pressure distribution of the 8-lobe after-body from the influence of the primary jet. A ring-airfoil shroud increased the static thrust of the annular nozzle but generally decreased the thrust minus drag at transonic Mach numbers.

  2. Performance and cavitation characteristics of bi-directional hydrofoils

    Science.gov (United States)

    Nedyalkov, Ivaylo; Wosnik, Martin

    2013-11-01

    Tidal turbines extract energy from flows which reverse direction. One way to address this bi-directionality in horizontal axis turbines that avoid the use of complex and maintenance-intensive yaw or blade pitch mechanisms, is to design bi-directional blades which perform (equally) well in either flow direction. A large number of proposed hydrofoil designs were investigated using numerical simulations. Selected candidate foils were also tested (at various speeds and angles of attack) in the High-Speed Cavitation Tunnel (HICaT) at the University of New Hampshire. Lift and drag were measured using a force balance, and cavitation inception and desinence were recorded. Experimental and numerical results were compared, and the foils were compared to each other and to reference foils. Bi-directional hydrofoils may provide a feasible solution to the problem of reversing flow direction, when their performance and cavitation characteristics are comparable to those for unidirectional foils, and the penalty in decreased energy production is outweighed by the cost reduction due to lower complexity and respectively lower installation and maintenance costs.

  3. Network Performance and Quality of Experience of Remote Access Laboratories

    Directory of Open Access Journals (Sweden)

    Alexander A. Kist

    2012-11-01

    Full Text Available Remote Access Laboratories (RAL have become important learning and teaching tools. This paper presents a performance study that targets a specific remote access architecture implemented within a universities operational environment. This particular RAL system provides globally authenticated and arbitrated remote access to virtualized computers as well as computer controlled hardware experiments. This paper presents system performance results that have been obtained utilizing both a set of automated and human subject tests. Principle objectives of the study were: To gain a better understanding of the nature of network traffic caused by experimental activity usage; to obtain an indication of user expectations of activity performance; and to develop a measure to predict Quality of Experience, based on easily measurable Quality of Service parameters. The study emulates network layer variation of access-bandwidth and round-trip-time of typical usage scenarios and contrasts against user perception results that allow classifying expected user performance. It demonstrates that failure rate is excellent measure of usability, and that round-trip-time predominantly affects user experience. Thin-client and remote desktop architectures are popular to separate the location of users and the actual data processing and use similar structures, hence results of this study to be applied in these application areas as well.

  4. A Framework to Implement IoT Network Performance Modelling Techniques for Network Solution Selection

    Directory of Open Access Journals (Sweden)

    Declan T. Delaney

    2016-12-01

    Full Text Available No single network solution for Internet of Things (IoT networks can provide the required level of Quality of Service (QoS for all applications in all environments. This leads to an increasing number of solutions created to fit particular scenarios. Given the increasing number and complexity of solutions available, it becomes difficult for an application developer to choose the solution which is best suited for an application. This article introduces a framework which autonomously chooses the best solution for the application given the current deployed environment. The framework utilises a performance model to predict the expected performance of a particular solution in a given environment. The framework can then choose an apt solution for the application from a set of available solutions. This article presents the framework with a set of models built using data collected from simulation. The modelling technique can determine with up to 85% accuracy the solution which performs the best for a particular performance metric given a set of solutions. The article highlights the fractured and disjointed practice currently in place for examining and comparing communication solutions and aims to open a discussion on harmonising testing procedures so that different solutions can be directly compared and offers a framework to achieve this within IoT networks.

  5. A Framework to Implement IoT Network Performance Modelling Techniques for Network Solution Selection.

    Science.gov (United States)

    Delaney, Declan T; O'Hare, Gregory M P

    2016-12-01

    No single network solution for Internet of Things (IoT) networks can provide the required level of Quality of Service (QoS) for all applications in all environments. This leads to an increasing number of solutions created to fit particular scenarios. Given the increasing number and complexity of solutions available, it becomes difficult for an application developer to choose the solution which is best suited for an application. This article introduces a framework which autonomously chooses the best solution for the application given the current deployed environment. The framework utilises a performance model to predict the expected performance of a particular solution in a given environment. The framework can then choose an apt solution for the application from a set of available solutions. This article presents the framework with a set of models built using data collected from simulation. The modelling technique can determine with up to 85% accuracy the solution which performs the best for a particular performance metric given a set of solutions. The article highlights the fractured and disjointed practice currently in place for examining and comparing communication solutions and aims to open a discussion on harmonising testing procedures so that different solutions can be directly compared and offers a framework to achieve this within IoT networks.

  6. An exploratory analysis of network characteristics and quality of interactions among public health collaboratives

    Directory of Open Access Journals (Sweden)

    Danielle M. Varda

    2012-06-01

    Full Text Available While the benefits of collaboration have become widely accepted and the practice of collaboration is growing within the public health system, a paucity of research exists that examines factors and mechanisms related to effective collaboration between public health and their partner organizations. The purpose of this paper is to address this gap by exploring the structural and organizational characteristics of public health collaboratives. Design and Methods. Using both social network analysis and traditional statistical methods, we conduct an exploratory secondary data analysis of 11 public health collaboratives chosen from across the United States. All collaboratives are part of the PARTNER (www.partnertool.net database. We analyze data to identify relational patterns by exploring the structure (the way that organizations connect and exchange relationships, in relation to perceptions of value and trust, explanations for varying reports of success, and factors related to outcomes. We describe the characteristics of the collaboratives, types of resource contributions, outcomes of the collaboratives, perceptions of success, and reasons for success. We found high variation and significant differences within and between these collaboratives including perceptions of success. There were significant relationships among various factors such as resource contributions, reasons cited for success, and trust and value perceived by organizations. We find that although the unique structure of each collaborative makes it challenging to identify a specific set of factors to determine when a collaborative will be successful, the organizational characteristics and interorganizational dynamics do appear to impact outcomes. We recommend a quality improvement process that suggests matching assessment to goals and developing action steps for performance improvement.

  7. An Exploratory Analysis of Network Characteristics and Quality of Interactions among Public Health Collaboratives.

    Science.gov (United States)

    Varda, Danielle M; Retrum, Jessica H

    2012-06-15

    While the benefits of collaboration have become widely accepted and the practice of collaboration is growing within the public health system, a paucity of research exists that examines factors and mechanisms related to effective collaboration between public health and their partner organizations. The purpose of this paper is to address this gap by exploring the structural and organizational characteristics of public health collaboratives. Design and Methods. Using both social network analysis and traditional statistical methods, we conduct an exploratory secondary data analysis of 11 public health collaboratives chosen from across the United States. All collaboratives are part of the PARTNER (www.partnertool.net) database. We analyze data to identify relational patterns by exploring the structure (the way that organizations connect and exchange relationships), in relation to perceptions of value and trust, explanations for varying reports of success, and factors related to outcomes. We describe the characteristics of the collaboratives, types of resource contributions, outcomes of the collaboratives, perceptions of success, and reasons for success. We found high variation and significant differences within and between these collaboratives including perceptions of success. There were significant relationships among various factors such as resource contributions, reasons cited for success, and trust and value perceived by organizations. We find that although the unique structure of each collaborative makes it challenging to identify a specific set of factors to determine when a collaborative will be successful, the organizational characteristics and interorganizational dynamics do appear to impact outcomes. We recommend a quality improvement process that suggests matching assessment to goals and developing action steps for performance improvement. the authors would like to thank the Robert Wood Johnson Foundation's Public Health Program for funding for this research.

  8. Performance characteristics of a Kodak computed radiography system.

    Science.gov (United States)

    Bradford, C D; Peppler, W W; Dobbins, J T

    1999-01-01

    The performance characteristics of a photostimulable phosphor based computed radiographic (CR) system were studied. The modulation transfer function (MTF), noise power spectra (NPS), and detective quantum efficiency (DQE) of the Kodak Digital Science computed radiography (CR) system (Eastman Kodak Co.-model 400) were measured and compared to previously published results of a Fuji based CR system (Philips Medical Systems-PCR model 7000). To maximize comparability, the same measurement techniques and analysis methods were used. The DQE at four exposure levels (30, 3, 0.3, 0.03 mR) and two plate types (standard and high resolution) were calculated from the NPS and MTF measurements. The NPS was determined from two-dimensional Fourier analysis of uniformly exposed plates. The presampling MTF was determined from the Fourier transform (FT) of the system's finely sampled line spread function (LSF) as produced by a narrow slit. A comparison of the slit type ("beveled edge" versus "straight edge") and its effect on the resulting MTF measurements was also performed. The results show that both systems are comparable in resolution performance. The noise power studies indicated a higher level of noise for the Kodak images (approximately 20% at the low exposure levels and 40%-70% at higher exposure levels). Within the clinically relevant exposure range (0.3-3 mR), the resulting DQE for the Kodak plates ranged between 20%-50% lower than for the corresponding Fuji plates. Measurements of the presampling MTF with the two slit types have shown that a correction factor can be applied to compensate for transmission through the relief edges.

  9. Performance and flow characteristics of MHD seawater thruster

    Energy Technology Data Exchange (ETDEWEB)

    Doss, E.D.

    1990-01-01

    The main goal of the research is to investigate the effects of strong magnetic fields on the electrical and flow fields inside MHD thrusters. The results of this study is important in the assessment of the feasibility of MHD seawater propulsion for the Navy. To accomplish this goal a three-dimensional fluid flow computer model has been developed and applied to study the concept of MHD seawater propulsion. The effects of strong magnetic fields on the current and electric fields inside the MHD thruster and their interaction with the flow fields, particularly those in the boundary layers, have been investigated. The results of the three-dimensional computations indicate that the velocity profiles are flatter over the sidewalls of the thruster walls in comparison to the velocity profiles over the electrode walls. These nonuniformities in the flow fields give rise to nonuniform distribution of the skin friction along the walls of the thrusters, where higher values are predicted over the sidewalls relative to those over the electrode walls. Also, a parametric study has been performed using the three-dimensional MHD flow model to analyze the performance of continuous electrode seawater thrusters under different operating parameters. The effects of these parameters on the fluid flow characteristics, and on the thruster efficiency have been investigated. Those parameters include the magnetic field (10--20 T), thruster diameter, surface roughness, flow velocity, and the electric load factor. The results show also that the thruster performance improves with the strength of the magnetic field and thruster diameter, and the efficiency decreases with the flow velocity and surface roughness.

  10. High-performance, scalable optical network-on-chip architectures

    Science.gov (United States)

    Tan, Xianfang

    The rapid advance of technology enables a large number of processing cores to be integrated into a single chip which is called a Chip Multiprocessor (CMP) or a Multiprocessor System-on-Chip (MPSoC) design. The on-chip interconnection network, which is the communication infrastructure for these processing cores, plays a central role in a many-core system. With the continuously increasing complexity of many-core systems, traditional metallic wired electronic networks-on-chip (NoC) became a bottleneck because of the unbearable latency in data transmission and extremely high energy consumption on chip. Optical networks-on-chip (ONoC) has been proposed as a promising alternative paradigm for electronic NoC with the benefits of optical signaling communication such as extremely high bandwidth, negligible latency, and low power consumption. This dissertation focus on the design of high-performance and scalable ONoC architectures and the contributions are highlighted as follow: 1. A micro-ring resonator (MRR)-based Generic Wavelength-routed Optical Router (GWOR) is proposed. A method for developing any sized GWOR is introduced. GWOR is a scalable non-blocking ONoC architecture with simple structure, low cost and high power efficiency compared to existing ONoC designs. 2. To expand the bandwidth and improve the fault tolerance of the GWOR, a redundant GWOR architecture is designed by cascading different type of GWORs into one network. 3. The redundant GWOR built with MRR-based comb switches is proposed. Comb switches can expand the bandwidth while keep the topology of GWOR unchanged by replacing the general MRRs with comb switches. 4. A butterfly fat tree (BFT)-based hybrid optoelectronic NoC (HONoC) architecture is developed in which GWORs are used for global communication and electronic routers are used for local communication. The proposed HONoC uses less numbers of electronic routers and links than its counterpart of electronic BFT-based NoC. It takes the advantages of

  11. Differences in daily disposable circle lens performance characteristics

    Directory of Open Access Journals (Sweden)

    Schafer JM

    2014-04-01

    Full Text Available Jeffery M Schafer, William T Reindel, Marjorie J Rah, Osbert Chan, Lening Zhang Bausch & Lomb Incorporated, Rochester, NY, USA Purpose: The purpose of this evaluation was to compare the performance characteristics of two cosmetically tinted contact lenses in the circle lens category that differ in lens design, lens material, and pigment print pattern: etafilcon A (1-Day Acuvue Define; Johnson & Johnson Vision Care and hilafilcon B (Naturelle; Bausch & Lomb Incorporated. Methods: Two hundred Asian subjects (400 eyes were enrolled in this 1-month parallel, bilateral, randomized study at ten investigative sites. Study lenses were dispensed at a screening/dispensing visit, and follow-up visits occurred at 2 weeks and 1 month. Lenses were worn on a daily disposable basis. Fit characteristics were evaluated at each visit, and slit-lamp evaluations were completed at each follow-up visit. Results: Of the 200 patients enrolled, 172 (344 eyes completed the study. The proportion of eyes with fully centered lenses was statistically significantly higher for the hilafilcon B group at the 2-week and 1-month visits, P<0.05. Over all visits, 0.6% of hilafilcon B eyes demonstrated incomplete corneal coverage, whereas for the etafilcon A group, 8.5% of eyes demonstrated incomplete corneal coverage and/or edge lift. The proportion of eyes with adequate lens movement was statistically significantly higher for the hilafilcon B group, P<0.05. Over all visits, none of the hilafilcon B eyes was reported to have excessive movement, whereas for etafilcon A lenses, 10.2% of eyes were reported to have excessive movement. Conclusions: Etafilcon A lenses were significantly less likely to be fully centered and significantly more likely to have incomplete corneal coverage and/or edge lift compared with the hilafilcon B lenses. Keywords: cosmetic contact lens, circle contact lens

  12. Analyzing topological characteristics of neuronal functional networks in the rat brain

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Hu [School of Computer Science and Communication Engineering, Jiangsu University, Jiangsu 212003 (China); School of Computer Science, Fudan University, Shanghai 200433 (China); Yang, Shengtao [Institutes of Brain Science, Fudan University, Shanghai 200433 (China); Song, Yuqing [School of Computer Science and Communication Engineering, Jiangsu University, Jiangsu 212003 (China); Wei, Hui [School of Computer Science, Fudan University, Shanghai 200433 (China)

    2014-08-28

    In this study, we recorded spike trains from brain cortical neurons of several behavioral rats in vivo by using multi-electrode recordings. An NFN was constructed in each trial, obtaining a total of 150 NFNs in this study. The topological characteristics of NFNs were analyzed by using the two most important characteristics of complex networks, namely, small-world structure and community structure. We found that the small-world properties exist in different NFNs constructed in this study. Modular function Q was used to determine the existence of community structure in NFNs, through which we found that community-structure characteristics, which are related to recorded spike train data sets, are more evident in the Y-maze task than in the DM-GM task. Our results can also be used to analyze further the relationship between small-world characteristics and the cognitive behavioral responses of rats. - Highlights: • We constructed the neuronal function networks based on the recorded neurons. • We analyzed the two main complex network characteristics, namely, small-world structure and community structure. • NFNs which were constructed based on the recorded neurons in this study exhibit small-world properties. • Some NFNs have community structure characteristics.

  13. Analyzing topological characteristics of neuronal functional networks in the rat brain

    International Nuclear Information System (INIS)

    Lu, Hu; Yang, Shengtao; Song, Yuqing; Wei, Hui

    2014-01-01

    In this study, we recorded spike trains from brain cortical neurons of several behavioral rats in vivo by using multi-electrode recordings. An NFN was constructed in each trial, obtaining a total of 150 NFNs in this study. The topological characteristics of NFNs were analyzed by using the two most important characteristics of complex networks, namely, small-world structure and community structure. We found that the small-world properties exist in different NFNs constructed in this study. Modular function Q was used to determine the existence of community structure in NFNs, through which we found that community-structure characteristics, which are related to recorded spike train data sets, are more evident in the Y-maze task than in the DM-GM task. Our results can also be used to analyze further the relationship between small-world characteristics and the cognitive behavioral responses of rats. - Highlights: • We constructed the neuronal function networks based on the recorded neurons. • We analyzed the two main complex network characteristics, namely, small-world structure and community structure. • NFNs which were constructed based on the recorded neurons in this study exhibit small-world properties. • Some NFNs have community structure characteristics

  14. Optimizing the ASC WAN: evaluating network performance tools for comparing transport protocols.

    Energy Technology Data Exchange (ETDEWEB)

    Lydick, Christopher L.

    2007-07-01

    The Advanced Simulation & Computing Wide Area Network (ASC WAN), which is a high delay-bandwidth network connection between US Department of Energy National Laboratories, is constantly being examined and evaluated for efficiency. One of the current transport-layer protocols which is used, TCP, was developed for traffic demands which are different from that on the ASC WAN. The Stream Control Transport Protocol (SCTP), on the other hand, has shown characteristics which make it more appealing to networks such as these. Most important, before considering a replacement for TCP on any network, a testing tool that performs well against certain criteria needs to be found. In order to try to find such a tool, two popular networking tools (Netperf v.2.4.3 & v.2.4.6 (OpenSS7 STREAMS), and Iperf v.2.0.6) were tested. These tools implement both TCP and SCTP and were evaluated using four metrics: (1) How effectively can the tool reach a throughput near the bandwidth? (2) How much of the CPU does the tool utilize during operation? (3) Is the tool freely and widely available? And, (4) Is the tool actively developed? Following the analysis of those tools, this paper goes further into explaining some recommendations and ideas for future work.

  15. Assessment of Student Music Performances Using Deep Neural Networks

    Directory of Open Access Journals (Sweden)

    Kumar Ashis Pati

    2018-03-01

    Full Text Available Music performance assessment is a highly subjective task often relying on experts to gauge both the technical and aesthetic aspects of the performance from the audio signal. This article explores the task of building computational models for music performance assessment, i.e., analyzing an audio recording of a performance and rating it along several criteria such as musicality, note accuracy, etc. Much of the earlier work in this area has been centered around using hand-crafted features intended to capture relevant aspects of a performance. However, such features are based on our limited understanding of music perception and may not be optimal. In this article, we propose using Deep Neural Networks (DNNs for the task and compare their performance against a baseline model using standard and hand-crafted features. We show that, using input representations at different levels of abstraction, DNNs can outperform the baseline models across all assessment criteria. In addition, we use model analysis techniques to further explain the model predictions in an attempt to gain useful insights into the assessment process. The results demonstrate the potential of using supervised feature learning techniques to better characterize music performances.

  16. Network and User-Perceived Performance of Web Page Retrievals

    Science.gov (United States)

    Kruse, Hans; Allman, Mark; Mallasch, Paul

    1998-01-01

    The development of the HTTP protocol has been driven by the need to improve the network performance of the protocol by allowing the efficient retrieval of multiple parts of a web page without the need for multiple simultaneous TCP connections between a client and a server. We suggest that the retrieval of multiple page elements sequentially over a single TCP connection may result in a degradation of the perceived performance experienced by the user. We attempt to quantify this perceived degradation through the use of a model which combines a web retrieval simulation and an analytical model of TCP operation. Starting with the current HTTP/l.1 specification, we first suggest a client@side heuristic to improve the perceived transfer performance. We show that the perceived speed of the page retrieval can be increased without sacrificing data transfer efficiency. We then propose a new client/server extension to the HTTP/l.1 protocol to allow for the interleaving of page element retrievals. We finally address the issue of the display of advertisements on web pages, and in particular suggest a number of mechanisms which can make efficient use of IP multicast to send advertisements to a number of clients within the same network.

  17. The Relationship of Policymaking and Networking Characteristics among Leaders of Large Urban Health Departments.

    Science.gov (United States)

    Leider, Jonathon P; Castrucci, Brian C; Harris, Jenine K; Hearne, Shelley

    2015-08-06

    The relationship between policy networks and policy development among local health departments (LHDs) is a growing area of interest to public health practitioners and researchers alike. In this study, we examine policy activity and ties between public health leadership across large urban health departments. This study uses data from a national profile of local health departments as well as responses from a survey sent to three staff members (local health official, chief of policy, chief science officer) in each of 16 urban health departments in the United States. Network questions related to frequency of contact with health department personnel in other cities. Using exponential random graph models, network density and centrality were examined, as were patterns of communication among those working on several policy areas using exponential random graph models. All 16 LHDs were active in communicating about chronic disease as well as about use of alcohol, tobacco, and other drugs (ATOD). Connectedness was highest among local health officials (density = .55), and slightly lower for chief science officers (d = .33) and chiefs of policy (d = .29). After accounting for organizational characteristics, policy homophily (i.e., when two network members match on a single characteristic) and tenure were the most significant predictors of formation of network ties. Networking across health departments has the potential for accelerating the adoption of public health policies. This study suggests similar policy interests and formation of connections among senior leadership can potentially drive greater connectedness among other staff.

  18. The Relationship of Policymaking and Networking Characteristics among Leaders of Large Urban Health Departments

    Directory of Open Access Journals (Sweden)

    Jonathon P. Leider

    2015-08-01

    Full Text Available Background: The relationship between policy networks and policy development among local health departments (LHDs is a growing area of interest to public health practitioners and researchers alike. In this study, we examine policy activity and ties between public health leadership across large urban health departments. Methods: This study uses data from a national profile of local health departments as well as responses from a survey sent to three staff members (local health official, chief of policy, chief science officer in each of 16 urban health departments in the United States. Network questions related to frequency of contact with health department personnel in other cities. Using exponential random graph models, network density and centrality were examined, as were patterns of communication among those working on several policy areas using exponential random graph models. Results: All 16 LHDs were active in communicating about chronic disease as well as about use of alcohol, tobacco, and other drugs (ATOD. Connectedness was highest among local health officials (density = .55, and slightly lower for chief science officers (d = .33 and chiefs of policy (d = .29. After accounting for organizational characteristics, policy homophily (i.e., when two network members match on a single characteristic and tenure were the most significant predictors of formation of network ties. Conclusion: Networking across health departments has the potential for accelerating the adoption of public health policies. This study suggests similar policy interests and formation of connections among senior leadership can potentially drive greater connectedness among other staff.

  19. Argonne National Laboratory high performance network support of APS experiments

    International Nuclear Information System (INIS)

    Knot, M.J.; McMahon, R.J.

    1996-01-01

    Argonne National Laboratory is currently positioned to provide access to high performance regional and national networks. Much of the impetus for this effort is the anticipated needs of the upcoming experimental program at the APS. Some APS collaborative access teams (CATs) are already pressing for network speed improvements and security enhancements. Requirements range from the need for high data rate, secure transmission of experimental data, to the desire to establish a open-quote open-quote virtual experimental environment close-quote close-quote at their home institution. In the near future, 155 megabit/sec (Mb/s) national and regional asynchronous transfer mode (ATM) networks will be operational and available to APS users. Full-video teleconferencing, virtual presence operation of experiments, and high speed, secure transmission of data are being tested and, in some cases, will be operational. We expect these efforts to enable a substantial improvement in the speed of processing experimental results as well as an increase in convenience to the APS experimentalist. copyright 1996 American Institute of Physics

  20. Characteristics of Social Network Gamers: in between Social Networking and Online Role-Playing Games

    Directory of Open Access Journals (Sweden)

    Olga eGeisel

    2015-07-01

    Full Text Available Current research on internet addiction (IA reported moderate to high prevalence rates of IA and comorbid psychiatric symptoms in users of social networking sites (SNS and online role-playing games. The aim of this study was to characterise adult users of an internet multiplayer strategy game within a SNS. Therefore, we conducted an exploratory study using an online survey to assess sociodemographic variables, psychopathology and the rate of IA in a sample of adult social network gamers by Young´s Internet Addiction Test (IAT, the Toronto Alexithymia Scale (TAS, the Beck Depression Inventory II (BDI-II, the Symptom Checklist-90-R (SCL-90-R and the WHO Quality of Life-BREF (WHOQOL-BREF. All participants were listed gamers of combat zone in the SNS Facebook. In the IAT analysis, 16.2 % of the participants (n = 60 were categorized as subjects with IA and 19.5 % (n = 72 fulfilled the criteria for alexithymia. Comparing study participants with and without IA, the IA group had significantly more subjects with alexithymia, reported more depressive symptoms, and showed poorer quality of life. These findings suggest that social network gaming might also be associated with maladaptive patterns of internet use. Furthermore, a relationship between IA, alexithymia and depressive symptoms was found that needs to be elucidated by future studies.

  1. Modeling interacting dynamic networks: I. Preferred degree networks and their characteristics

    International Nuclear Information System (INIS)

    Liu, Wenjia; Schmittmann, Beate; Zia, R K P; Jolad, Shivakumar

    2013-01-01

    We study a simple model of dynamic networks, characterized by a set preferred degree, κ. Each node with degree k attempts to maintain its κ and will add (cut) a link with probability w(k;κ) (1 − w(k;κ)). As a starting point, we consider a homogeneous population, where each node has the same κ, and examine several forms of w(k;κ), inspired by Fermi–Dirac functions. Using Monte Carlo simulations, we find the degree distribution in the steady state. In contrast to the well known Erdős–Rényi network, our degree distribution is not a Poisson distribution; yet its behavior can be understood by an approximate theory. Next, we introduce a second preferred degree network and couple it to the first by establishing a controllable fraction of inter-group links. For this model, we find both understandable and puzzling features. Generalizing the prediction for the homogeneous population, we are able to explain the total degree distributions well, but not the intra- or inter-group degree distributions. When monitoring the total number of inter-group links, X, we find very surprising behavior. X explores almost the full range between its maximum and minimum allowed values, resulting in a flat steady-state distribution, reminiscent of a simple random walk confined between two walls. Both simulation results and analytic approaches will be discussed. (paper)

  2. Error performance analysis in downlink cellular networks with interference management

    KAUST Repository

    Afify, Laila H.; Elsawy, Hesham; Al-Naffouri, Tareq Y.; Alouini, Mohamed-Slim

    2015-01-01

    Modeling aggregate network interference in cellular networks has recently gained immense attention both in academia and industry. While stochastic geometry based models have succeeded to account for the cellular network geometry, they mostly

  3. OpenFlow Switching Performance using Network Simulator - 3

    OpenAIRE

    Sriram Prashanth, Naguru

    2016-01-01

    Context. In the present network inventive world, there is a quick expansion of switches and protocols, which are used to cope up with the increase in customer requirement in the networking. With increasing demand for higher bandwidths and lower latency and to meet these requirements new network paths are introduced. To reduce network load in present switching network, development of new innovative switching is required. These required results can be achieved by Software Define Network or Trad...

  4. Key Performance Characteristics of Organic Shrimp Aquaculture in Southwest Bangladesh

    Directory of Open Access Journals (Sweden)

    Christian Reinhard Vogl

    2012-05-01

    Full Text Available In Bangladesh, black tiger shrimp (Penaeus monodon; Fabricius, 1798 aquaculture has come to be one of the most important sectors in both the rural and national economies. Likewise, organic shrimp aquaculture has emerged as an alternative farming enterprise for farmers especially in the southwestern districts of Bangladesh. The present study aims to show key performance characteristics of organic shrimp farmers and farming in a prototypical shrimp farming area in Bangladesh. Data was collected in 2009 from organic shrimp farmers in the Kaligonj and Shyamnagar sub-districts through questionnaire interviews, transect walks and focus group discussions. The mean productivity of organic shrimp farming in the area is 320 kg ha−1 yr−1 (ranging from 120 to 711 kg ha−1year−1. Organic farmers are more likely to have a higher monthly income and less aquaculture experience. Moreover, suitable landholdings and classified labor distribution have been found to play an important role in the development of organic shrimp aquaculture. The most common assets of organic shrimp aquaculture are high yield, low production cost, available post larvae and high market prices. Small business farmers are likely to earn more income benefits from organic shrimp aquaculture than their larger-scale counterparts. Finally, the paper suggests that more research is needed to stimulate the success of organic shrimp aquaculture.

  5. Dynamic Performance Characteristic Tests of Real Scale Lead Rubber Bearing for the Evaluation of Performance Criteria

    International Nuclear Information System (INIS)

    Kim, Min Kyu; Kim, Jung-Han; Choi, In-Kil

    2014-01-01

    Dynamic characteristic tests of full scale lead rubber bearing were performed for the evaluation of performance criteria of isolation system for nuclear power plants. For the dynamic test for a full scale rubber bearing, two 1500mm diameter lead rubber bearings were manufactured. The viewpoints of this dynamic test are determination of an ultimate shear strain level of lead rubber bearing, behavior of rubber bearing according to static and dynamic input motion, sinusoidal and random (earthquake) motion, and 1-dimentional and 2-dimensional input motion. In this study, seismic isolation device tests were performed for the evaluation of performance criteria of isolation system. Through this test, it can be recognized that in the case of considering a mechanical property test, dynamic and multi degree of loading conditions should be determined. But these differences should be examined how much affect to the global structural behavior

  6. Performance Study of Earth Networks Total Lightning Network using Rocket-Triggered Lightning Data in 2014

    Science.gov (United States)

    Heckman, S.

    2015-12-01

    Modern lightning locating systems (LLS) provide real-time monitoring and early warning of lightningactivities. In addition, LLS provide valuable data for statistical analysis in lightning research. It isimportant to know the performance of such LLS. In the present study, the performance of the EarthNetworks Total Lightning Network (ENTLN) is studied using rocket-triggered lightning data acquired atthe International Center for Lightning Research and Testing (ICLRT), Camp Blanding, Florida.In the present study, 18 flashes triggered at ICLRT in 2014 were analyzed and they comprise of 78negative cloud-to-ground return strokes. The geometric mean, median, minimum, and maximum for thepeak currents of the 78 return strokes are 13.4 kA, 13.6 kA, 3.7 kA, and 38.4 kA, respectively. The peakcurrents represent typical subsequent return strokes in natural cloud-to-ground lightning.Earth Networks has developed a new data processor to improve the performance of their network. Inthis study, results are presented for the ENTLN data using the old processor (originally reported in 2014)and the ENTLN data simulated using the new processor. The flash detection efficiency, stroke detectionefficiency, percentage of misclassification, median location error, median peak current estimation error,and median absolute peak current estimation error for the originally reported data from old processorare 100%, 94%, 49%, 271 m, 5%, and 13%, respectively, and those for the simulated data using the newprocessor are 100%, 99%, 9%, 280 m, 11%, and 15%, respectively. The use of new processor resulted inhigher stroke detection efficiency and lower percentage of misclassification. It is worth noting that theslight differences in median location error, median peak current estimation error, and median absolutepeak current estimation error for the two processors are due to the fact that the new processordetected more number of return strokes than the old processor.

  7. Multi-objective optimal power flow for active distribution network considering the stochastic characteristic of photovoltaic

    Science.gov (United States)

    Zhou, Bao-Rong; Liu, Si-Liang; Zhang, Yong-Jun; Yi, Ying-Qi; Lin, Xiao-Ming

    2017-05-01

    To mitigate the impact on the distribution networks caused by the stochastic characteristic and high penetration of photovoltaic, a multi-objective optimal power flow model is proposed in this paper. The regulation capability of capacitor, inverter of photovoltaic and energy storage system embedded in active distribution network are considered to minimize the expected value of active power the T loss and probability of voltage violation in this model. Firstly, a probabilistic power flow based on cumulant method is introduced to calculate the value of the objectives. Secondly, NSGA-II algorithm is adopted for optimization to obtain the Pareto optimal solutions. Finally, the best compromise solution can be achieved through fuzzy membership degree method. By the multi-objective optimization calculation of IEEE34-node distribution network, the results show that the model can effectively improve the voltage security and economy of the distribution network on different levels of photovoltaic penetration.

  8. Attentional Performance is Correlated with the Local Regional Efficiency of Intrinsic Brain Networks

    Directory of Open Access Journals (Sweden)

    Junhai eXu

    2015-07-01

    Full Text Available Attention is a crucial brain function for human beings. Using neuropsychological paradigms and task-based functional brain imaging, previous studies have indicated that widely distributed brain regions are engaged in three distinct attention subsystems: alerting, orienting and executive control (EC. Here, we explored the potential contribution of spontaneous brain activity to attention by examining whether resting-state activity could account for individual differences of the attentional performance in normal individuals. The resting-state functional images and behavioral data from attention network test (ANT task were collected in 59 healthy subjects. Graph analysis was conducted to obtain the characteristics of functional brain networks and linear regression analyses were used to explore their relationships with behavioral performances of the three attentional components. We found that there was no significant relationship between the attentional performance and the global measures, while the attentional performance was associated with specific local regional efficiency. These regions related to the scores of alerting, orienting and EC largely overlapped with the regions activated in previous task-related functional imaging studies, and were consistent with the intrinsic dorsal and ventral attention networks (DAN/VAN. In addition, the strong associations between the attentional performance and specific regional efficiency suggested that there was a possible relationship between the DAN/VAN and task performances in the ANT. We concluded that the intrinsic activity of the human brain could reflect the processing efficiency of the attention system. Our findings revealed a robust evidence for the functional significance of the efficiently organized intrinsic brain network for highly productive cognitions and the hypothesized role of the DAN/ VAN at rest.

  9. CPN based fault-tolerance performance evaluation of fieldbus for KNGR NPCS network

    International Nuclear Information System (INIS)

    Jung, Hyun Gi; Seong, Poong Hyun

    1998-01-01

    In contrast with conventional Fieldbus researches which are focused on real time performanc ignoring fault-tolerant mechanisms, the aim of this work is real-time performance evaluation of the system including fault. Because the communication network will be applied to Next Generation NPP, maintaining performance in presence of recoverable fault is important. To guarantee this in NPP Control Network, we should investigate the time characteristics of the target system in case of recoverable fault. If the time characteristics meet the requirements of the system, the faults will be recovered by Fieldbus recovery mechanisms and the system will be safe. But, if time characteristics can not meet the requirements, the faults in the Fieldbus can propagate to system failure. For this purpose, we classified the recoverable faults, made the formula which represents delays including recovery mechaisms and made simulation model. We appied the simulation model to KNGR NPCS with some assumptions. The outcome of the simulation is reallistic delays of the fault cases which have been classified. From the outcome of the simulation and the system requirements, we can calculate failure propagation probability from Fieldbus to outer system

  10. Messaging Performance of FIPA Interaction Protocols in Networked Embedded Controllers

    Directory of Open Access Journals (Sweden)

    García JoséAPérez

    2008-01-01

    Full Text Available Abstract Agent-based technologies in production control systems could facilitate seamless reconfiguration and integration of mechatronic devices/modules into systems. Advances in embedded controllers which are continuously improving computational capabilities allow for software modularization and distribution of decisions. Agent platforms running on embedded controllers could hide the complexity of bootstrap and communication. Therefore, it is important to investigate the messaging performance of the agents whose main motivation is the resource allocation in manufacturing systems (i.e., conveyor system. The tests were implemented using the FIPA-compliant JADE-LEAP agent platform. Agent containers were distributed through networked embedded controllers, and agents were communicating using request and contract-net FIPA interaction protocols. The test scenarios are organized in intercontainer and intracontainer communications. The work shows the messaging performance for the different test scenarios using both interaction protocols.

  11. Messaging Performance of FIPA Interaction Protocols in Networked Embedded Controllers

    Directory of Open Access Journals (Sweden)

    Omar Jehovani López Orozco

    2007-12-01

    Full Text Available Agent-based technologies in production control systems could facilitate seamless reconfiguration and integration of mechatronic devices/modules into systems. Advances in embedded controllers which are continuously improving computational capabilities allow for software modularization and distribution of decisions. Agent platforms running on embedded controllers could hide the complexity of bootstrap and communication. Therefore, it is important to investigate the messaging performance of the agents whose main motivation is the resource allocation in manufacturing systems (i.e., conveyor system. The tests were implemented using the FIPA-compliant JADE-LEAP agent platform. Agent containers were distributed through networked embedded controllers, and agents were communicating using request and contract-net FIPA interaction protocols. The test scenarios are organized in intercontainer and intracontainer communications. The work shows the messaging performance for the different test scenarios using both interaction protocols.

  12. The Performance Parameters Of Wireless Sensor Networks In Underground Mines

    Directory of Open Access Journals (Sweden)

    Sinan UGUZ

    2015-08-01

    Full Text Available In recent years underground mines have increasingly remained on the agenda with both difficult working conditions and problems such as collapsed and firedamp explosion in our country and in the world. In terms of life safety of miners and their health mine sites are required to be continuously monitored and controlled. This is difficult to achieve with existing wired systems due to the topography of mine sites. The applications have increased with the development of wireless sensor networks WSN technology in mine sites in recent years. This case has also caused an increase in studies on improving WSN performance. Especially energy efficiency is very important for the WSN hardware with a low energy source. In this study information about things to consider while using WSN technologies in underground mines and studies on their performance has been provided.

  13. On PHY and MAC Performance in Body Sensor Networks

    Directory of Open Access Journals (Sweden)

    Higgins Henry

    2009-01-01

    Full Text Available Abstract This paper presents an empirical investigation on the performance of body implant communication using radio frequency (RF technology. In body implant communication, the electrical properties of the body influence the signal propagation in several ways. We use a Perspex body model (30 cm diameter, 80 cm height and 0.5 cm thickness filled with a liquid that mimics the electrical properties of the basic body tissues. This model is used to observe the effects of body tissue on the RF communication. We observe best performance at 3cm depth inside the liquid. We further present a simulation study of several low-power MAC protocols for an on-body sensor network and discuss the derived results. Also, the traditional preamble-based TMDA protocol is extended towards a beacon-based TDMA protocol in order to avoid preamble collision and to ensure low-power communication.

  14. On PHY and MAC Performance in Body Sensor Networks

    Directory of Open Access Journals (Sweden)

    Sana Ullah

    2009-01-01

    Full Text Available This paper presents an empirical investigation on the performance of body implant communication using radio frequency (RF technology. In body implant communication, the electrical properties of the body influence the signal propagation in several ways. We use a Perspex body model (30 cm diameter, 80 cm height and 0.5 cm thickness filled with a liquid that mimics the electrical properties of the basic body tissues. This model is used to observe the effects of body tissue on the RF communication. We observe best performance at 3cm depth inside the liquid. We further present a simulation study of several low-power MAC protocols for an on-body sensor network and discuss the derived results. Also, the traditional preamble-based TMDA protocol is extended towards a beacon-based TDMA protocol in order to avoid preamble collision and to ensure low-power communication.

  15. Social network characteristics and cervical cancer screening among Quechua women in Andean Peru.

    Science.gov (United States)

    Luque, John S; Opoku, Samuel; Ferris, Daron G; Guevara Condorhuaman, Wendy S

    2016-02-24

    Peru has high cervical cancer incidence and mortality rates compared to other Andean countries. Therefore, partnerships between governmental and international organizations have targeted rural areas of Peru to receive cervical cancer screening via outreach campaigns. Previous studies have found a relationship between a person's social networks and cancer screening behaviors. Screening outreach campaigns conducted by the nonprofit organization CerviCusco created an opportunity for a social network study to examine cervical cancer screening history and social network characteristics in a rural indigenous community that participated in these campaigns in 2012 and 2013. The aim of this study was to explore social network characteristics in this community related to receipt of cervical cancer screening following the campaigns. An egocentric social network questionnaire was used to collect cross-sectional network data on community participants. Each survey participant (ego) was asked to name six other women they knew (alters) and identify the nature of their relationship or tie (family, friend, neighbor, other), residential closeness (within 5 km), length of time known, frequency of communication, topics of conversation, and whether they lent money to the person, provided childcare or helped with transportation. In addition, each participant was asked to report the nature of the relationship between all alters identified (e.g., friend, family, or neighbor). Bivariate and multivariate analyses were used to explore the relationship between Pap test receipt at the CerviCusco outreach screening campaigns and social network characteristics. Bivariate results found significant differences in percentage of alter composition for neighbors and family, and for mean number of years known, mean density, and mean degree centrality between women who had received a Pap test (n = 19) compared to those who had not (n = 50) (p's < 0.05). The final logistic regression model was

  16. ESTABLISHED MODES AND STATIC CHARACTERISTICS OF THREE-PHASE ASYNCHRONOUS MOTOR POWERED WITH SINGLE PHASE NETWORK

    Directory of Open Access Journals (Sweden)

    V. S. Malyar

    2016-01-01

    Full Text Available A mathematical model is developed to study the operation of three-phase asynchronous motor with squirrel-cage rotor when the stator winding is powered from a single phase network. To create a rotating magnetic field one of the phases is fed through the capacitor. Due to the asymmetry of power feed not only transients, but the steady-state regimes are dynamic, so they are described by differential equations in any coordinate system. Their study cannot be carried out with sufficient adequacy on the basis of known equivalent circuits and require the use of dynamic parameters. In the mathematical model the state equations of the circuits of the stator and rotor are composed in the stationary three phase coordinate system. Calculation of the established mode is performed by solving the boundary problem that makes it possible to obtain the coordinate dependences over the period, without calculation of the transient process. In order to perform it, the original nonlinear differential equations are algebraized by approximating the variables with the use of cubic splines. The resulting nonlinear system of algebraic equations is a discrete analogue of the initial system of differential equations. It is solved by parameter continuation method. To calculate the static characteristics as a function of a certain variable, the system is analytically differentiated, and then numerically integrated over this variable. In the process of integration, Newton's refinement is performed at each step or at every few steps, making it possible to implement the integration in just a few steps using Euler's method. Jacobi matrices in both cases are the same. To account for the current displacement in the rods of the squirrel-cage rotor, each of them, along with the squirrel-cage rings, is divided in height into several elements. This results in several squirrel-cage rotor windings which are represented by three-phase windings with magnetic coupling between them.

  17. A performance based evaluation of SIP signalling across converged networks

    NARCIS (Netherlands)

    Oredope, A.; Liotta, A.

    2007-01-01

    As wireless networks evolves towards the 3G and 4G architectures the mobile core networks provides a platform for all-IP convergence of mobile and fixed networks allowing for better integration of the Internet and cellular networks, providing better quality of service, charging mechanisms and

  18. Social Network Characteristics, Social Support, and Cigarette Smoking among Asian/Pacific Islander Young Adults.

    Science.gov (United States)

    Pokhrel, Pallav; Fagan, Pebbles; Cassel, Kevin; Trinidad, Dennis R; Kaholokula, Joseph Keawe'aimoku; Herzog, Thaddeus A

    2016-06-01

    Cigarette smoking may be one of the factors contributing to the high levels of cancer-related mortality experienced by certain Asian/Pacific Islander (A/PI) subgroups (e.g., Native Hawaiian). Given the collectivist cultural orientation attributed to A/PI groups, social strategies are recommended for substance abuse or smoking cessation treatment among A/PI. However, research examining how social network characteristics and social support relate to smoking across A/PI subgroups has been lacking. This study investigated the associations between social network characteristics (e.g., size, composition), perceived social support, and recent cigarette use across Native Hawaiian, Filipino, and East Asian (e.g., Japanese, Chinese) young adults (18-35 year old). Cross-sectional, self-report data were collected from N = 435 participants (M age = 25.6, SD = 8.3; 61% women). Ethnic differences were found in a number of pathways linking social network characteristics, perceived social support, and cigarette smoking. Larger network size was strongly associated with higher perceived social support and lower recent cigarette smoking among Native Hawaiians but not Filipinos or East Asians. Higher perceived social support was associated with lower recent smoking among East Asians and Filipinos but not Native Hawaiians. Implications are discussed with regard to smoking prevention and cessation among A/PI. © Society for Community Research and Action 2016.

  19. [Characteristics of social supportive network serving the older female sex workers in Qingdao].

    Science.gov (United States)

    Xu, Y Q; Li, Y F; Jiang, Z X; Zhang, X J; Yuan, X; Zhang, N; Li, X F; Jiang, B F

    2016-02-01

    To overview the status of social support on older female sex workers (OFSWs) in Qingdao and to better understand the characteristics of this egocentric social support networks. Ucinet 6 software was used to analyze the characteristics of egocentric social networks which involving 400 OFSWs who were recruited by respondent-driven sampling (RDS) method in Qingdao during March 2014 to June. Structural equation model (SEM) was used for data analysis, fitted test and estimation. A total of 400 OFSWs of Qingdao nominated 1 617 social supportive members, and the average size of egocentric social networks of OFSWs was (4.0 ± 1.5). Among all the alter egos (social support network members of the egos), 613 were female sex workers fellows, accounted for the most important part of all the social ties (37.91%). Characteristics of small size and non-relative relationships were seen more obviously among OFSWs with non-local registration and the ratings of emotional support (4.42±2.38) was significantly lower than the tangible support (5.73 ± 1.69) (Psocial support from friends who were also female sex workers. Stronger the joint strength between egos and alters, greater the homogeneity between the two was seen. Tighter relations among the alter egos, higher degree of average social support of the egos were acquired.

  20. Evaluation of the Performance of Feedforward and Recurrent Neural Networks in Active Cancellation of Sound Noise

    Directory of Open Access Journals (Sweden)

    Mehrshad Salmasi

    2012-07-01

    Full Text Available Active noise control is based on the destructive interference between the primary noise and generated noise from the secondary source. An antinoise of equal amplitude and opposite phase is generated and combined with the primary noise. In this paper, performance of the neural networks is evaluated in active cancellation of sound noise. For this reason, feedforward and recurrent neural networks are designed and trained. After training, performance of the feedforwrad and recurrent networks in noise attenuation are compared. We use Elman network as a recurrent neural network. For simulations, noise signals from a SPIB database are used. In order to compare the networks appropriately, equal number of layers and neurons are considered for the networks. Moreover, training and test samples are similar. Simulation results show that feedforward and recurrent neural networks present good performance in noise cancellation. As it is seen, the ability of recurrent neural network in noise attenuation is better than feedforward network.

  1. Social networks of people with mild intellectual disabilities: characteristics, satisfaction, wishes and quality of life.

    Science.gov (United States)

    van Asselt-Goverts, A E; Embregts, P J C M; Hendriks, A H C

    2015-05-01

    A supportive social network is crucial for facilitating social inclusion, which can, in turn, contribute to the quality of life (QOL) for people with intellectual disabilities (ID). In this study, we investigate how people with mild ID perceive their social networks and which network characteristics relate to satisfaction with the network and perceived QOL. Data were gathered from 33 young adults with a mild to borderline ID using structured questionnaires: the MSNA to map the social network, the IDQOL-16 to assess QOL, and a questionnaire to determine satisfaction and wishes with regard to the social network. The majority of the participants (73.1%) were satisfied with their social networks. Improvement in the area of strengthening existing ties (e.g. more frequent contact, better contact) was desired as opposed to expansion of the network. Affection--especially towards family and professionals--was most strongly related to perceived QOL. It appears to be essential that relatives live in the same town, can frequently meet up and provide both emotional and practical support. The significance of family and the importance of high-quality interpersonal relationships between professional and client in the lives of young adults with ID cannot be overestimated. Although measures of satisfaction and wishes can have limitations, in actual practice it is considered useful to assess the opinions of clients with respect to their social networks. Interventions can then be tailored to the needs and wishes of the persons themselves. © 2014 MENCAP and International Association of the Scientific Study of Intellectual and Developmental Disabilities and John Wiley & Sons Ltd.

  2. Addressing the Influence of Hidden State on Wireless Network Optimizations using Performance Maps

    DEFF Research Database (Denmark)

    Højgaard-Hansen, Kim; Madsen, Tatiana Kozlova; Schwefel, Hans-Peter

    2015-01-01

    be used to optimize the use of the wireless net- work by predicting future network performance and scheduling the net- work communication for certain applications on mobile devices. However, other important factors influence the performance of the wireless communication such as changes in the propagation...... environment and resource sharing. In this work we extend the framework of performance maps for wireless networks by introducing network state as an abstraction for all other factors than location that influence the performance. Since network state might not always be directly observable the framework......Performance of wireless connectivity for network client devices is location dependent. It has been shown that it can be beneficial to collect network performance metrics along with location information to generate maps of the location dependent network performance. These performance maps can...

  3. Analyzing the Social Networks of High- and Low-Performing Students in Online Discussion Forums

    Science.gov (United States)

    Ghadirian, Hajar; Salehi, Keyvan; Ayub, Ahmad Fauzi Mohd

    2018-01-01

    An ego network is an individual's social network relationships with core members. In this study, the ego network parameters in online discussion spaces of high- and low-performing students were compared. The extent to which students' ego networks changed over the course were also analyzed. Participation in 7 weeks of online discussions were…

  4. On the estimation variance for the specific Euler-Poincaré characteristic of random networks.

    Science.gov (United States)

    Tscheschel, A; Stoyan, D

    2003-07-01

    The specific Euler number is an important topological characteristic in many applications. It is considered here for the case of random networks, which may appear in microscopy either as primary objects of investigation or as secondary objects describing in an approximate way other structures such as, for example, porous media. For random networks there is a simple and natural estimator of the specific Euler number. For its estimation variance, a simple Poisson approximation is given. It is based on the general exact formula for the estimation variance. In two examples of quite different nature and topology application of the formulas is demonstrated.

  5. A Set of Functional Brain Networks for the Comprehensive Evaluation of Human Characteristics

    Directory of Open Access Journals (Sweden)

    Yul-Wan Sung

    2018-03-01

    Full Text Available Many human characteristics must be evaluated to comprehensively understand an individual, and measurements of the corresponding cognition/behavior are required. Brain imaging by functional MRI (fMRI has been widely used to examine brain function related to human cognition/behavior. However, few aspects of cognition/behavior of individuals or experimental groups can be examined through task-based fMRI. Recently, resting state fMRI (rs-fMRI signals have been shown to represent functional infrastructure in the brain that is highly involved in processing information related to cognition/behavior. Using rs-fMRI may allow diverse information about the brain through a single MRI scan to be obtained, as rs-fMRI does not require stimulus tasks. In this study, we attempted to identify a set of functional networks representing cognition/behavior that are related to a wide variety of human characteristics and to evaluate these characteristics using rs-fMRI data. If possible, these findings would support the potential of rs-fMRI to provide diverse information about the brain. We used resting-state fMRI and a set of 130 psychometric parameters that cover most human characteristics, including those related to intelligence and emotional quotients and social ability/skill. We identified 163 brain regions by VBM analysis using regression analysis with 130 psychometric parameters. Next, using a 163 × 163 correlation matrix, we identified functional networks related to 111 of the 130 psychometric parameters. Finally, we made an 8-class support vector machine classifiers corresponding to these 111 functional networks. Our results demonstrate that rs-fMRI signals contain intrinsic information about brain function related to cognition/behaviors and that this set of 111 networks/classifiers can be used to comprehensively evaluate human characteristics.

  6. Network Degradation Effects on Different Codec Types and Characteristics of Video Streaming

    Directory of Open Access Journals (Sweden)

    Jaroslav Frnda

    2014-01-01

    Full Text Available Nowadays, there is a quickly growing demand for the transmission of voice, video and data over an IP based network. Multimedia, whether we are talking about broadcast, audio and video transmission and others, from a global perspective is growing exponentially with time. With incoming requests from users, new technologies for data transfer are continually developing. Data must be delivered reliably and with the fewest losses at such high speed. Video quality as part of multimedia technology has a very important role nowadays. It is influenced by several factors, where each of them can have many forms and processing. Network performance is the major degradation effect that influences the quality of resulting image. Poor network performance (lack of link capacity, high network load… causes data packet losses or different delivery time for each packet. This work focuses exactly on these network phenomena. It examines the impact of different delays and packet losses on the quality parameters of triple play services, to evaluate the results using objective methods. The aim of this work is to bring a detailed view on the performance of video streaming over IP-based networks.

  7. Structural characteristics of the online social networks of maltreated youth and offline sexual risk behavior.

    Science.gov (United States)

    Negriff, Sonya; Valente, Thomas W

    2018-02-07

    Maltreated youth are at risk for exposure to online sexual content and high-risk sexual behavior, yet characteristics of their online social networks have not been examined as a potential source of vulnerability. The aims of the current study were: 1) to test indicators of size (number of friends) and fragmentation (number of connections between friends) of maltreated young adults' online networks as predictors of intentional and unintentional exposure to sexual content and offline high-risk sexual behavior and 2) to test maltreatment as a moderator of these associations. Participants were selected from a longitudinal study on the effects of child maltreatment (n = 152; Mean age 21.84 years). Data downloaded from Facebook were used to calculate network variables of size (number of friends), density (connections between friends), average degree (average number of connections for each friend), and percent isolates (those not connected to others in the network). Self-reports of intentional and unintentional exposure to online sexual content and offline high-risk sexual behavior were the outcome variables. Multiple-group path modeling showed that only for the maltreated group having a higher percent of isolates in the network predicted intentional exposure to online sexual content and offline high-risk sexual behavior. An implication of this finding is that the composition of the Facebook network may be used as a risk indicator for individuals with child-welfare documented maltreatment experiences. Copyright © 2018. Published by Elsevier Ltd.

  8. Structure Characteristics of the International Stock Market Complex Network in the Perspective of Whole and Part

    Directory of Open Access Journals (Sweden)

    Guangxi Cao

    2017-01-01

    Full Text Available International stock market forms an abstract complex network through the fluctuation correlation of stock price index. Past studies of complex network almost focus on single country’s stock market. Here we investigate the whole and partial characteristics of international stock market network (ISMN (hereinafter referred to as ISMN. For the analysis on the whole network, we firstly determine the reasonable threshold as the basic of the following study. Robustness is applied to analyze the stability of the network and the result shows that ISMN has robustness against random attack but intentional attack breaks the connection integrity of ISMN rapidly. In the partial network, the sliding window method is used to analyze the dynamic evolution of the relationship between the Chinese (Shanghai stock market and the international stock market. The connection between the Chinese stock market and foreign stock markets becomes increasingly closer, and the links between them show a significant enhancement especially after China joined the WTO. In general, we suggest that transnational investors pay more attention to some significant event of the stock market with large degree for better risk-circumvention.

  9. Performance characteristics of mix oil biodiesel blends with smoke emissions

    Directory of Open Access Journals (Sweden)

    Sanjay Mohite

    2016-08-01

    July 10th 2016; Available online How to Cite This Article: Mohite. S, Kumar, S. &  Maji, S.  (2016 Performance  characteristics of mix oil biodiesel blends with smoke emissions. Int. Journal of Renewable Energy Development, 5(2, 163-170. http://dx.doi.org/10.14710/ijred.5.2.163-170 

  10. Spiking neural networks on high performance computer clusters

    Science.gov (United States)

    Chen, Chong; Taha, Tarek M.

    2011-09-01

    In this paper we examine the acceleration of two spiking neural network models on three clusters of multicore processors representing three categories of processors: x86, STI Cell, and NVIDIA GPGPUs. The x86 cluster utilized consists of 352 dualcore AMD Opterons, the Cell cluster consists of 320 Sony Playstation 3s, while the GPGPU cluster contains 32 NVIDIA Tesla S1070 systems. The results indicate that the GPGPU platform can dominate in performance compared to the Cell and x86 platforms examined. From a cost perspective, the GPGPU is more expensive in terms of neuron/s throughput. If the cost of GPGPUs go down in the future, this platform will become very cost effective for these models.

  11. Analiza karakteristika MPLS simulatora / Characteristics analyse of the MPLS network simulator

    Directory of Open Access Journals (Sweden)

    Boban Pavlović

    2005-05-01

    Full Text Available U ovom radu predstavljena je arhitektura i analizirane su karakteristike MPLS mrežnog simulatora MNS (Multiprotocol Label Switching Network Simulator, koji se koristi u projektovanju paketskih mreža zasnovanih na IP (Internet Protocol protokolu koje moraju podržavati saobraćaj u realnom vremenu i multimedijalni saobraćaj. Na bazi mrežnog simulatora prikazane su i opisane procedure simulacije saobraćaja različitog QoS, kao i simulacija posluživanja saobraćaja višeg prioriteta. / In this article are presented architecture and characteristics analyze of the MPLS Network Simulator (MNS. MNS is used for design packet networks based on Internet Protocol (IP which must support Real-time Traffic and Multimedia. In this document are presented and described simulation procedure for traffics -with different QoS and simulation for resource preemption.

  12. Hydraulic and separation characteristics of an industrial gas centrifuge calculated with neural networks

    Science.gov (United States)

    Butov, Vladimir; Timchenko, Sergey; Ushakov, Ivan; Golovkov, Nikita; Poberezhnikov, Andrey

    2018-03-01

    Single gas centrifuge (GC) is generally used for the separation of binary mixtures of isotopes. Processes taking place within the centrifuge are complex and non-linear. Their characteristics can change over time with long-term operation due to wear of the main structural elements of the GC construction. The paper is devoted to the determination of basic operation parameters of the centrifuge with the help of neural networks. We have developed a method for determining the parameters of the industrial GC operation by processing statistical data. In this work, we have constructed a neural network that is capable of determining the main hydraulic and separation characteristics of the gas centrifuge, depending on the geometric dimensions of the gas centrifuge, load value, and rotor speed.

  13. Personal Network Characteristics as Predictors of Change in Obesity Risk Behaviors in Early Adolescence.

    Science.gov (United States)

    Marks, Jennifer; de la Haye, Kayla; Barnett, Lisa M; Allender, Steven

    2018-05-17

    The potential for peers to influence obesity risk behavior increases in adolescence, yet there are knowledge gaps of how behaviors are modified in response to peers over time. This study examined how personal friendship network characteristics were associated with obesity-related behaviors from late childhood to early adolescence. Two waves of friendship, physical activity, screen time, and dietary recall data were collected from 11- to 13-year-old students (99% retention) in Australia (n = 308) over a five- to eight-month period. Regression models identified friendship network characteristics that predicted later health behaviors which varied by gender and behavior type, such as the number of friends positively associated with physical activity intensity (males) and screen time (females). The need for considering context to influence behavior change is discussed. © 2018 Society for Research on Adolescence.

  14. Friendship Network Characteristics Are Associated with Physical Activity and Sedentary Behavior in Early Adolescence.

    Science.gov (United States)

    Marks, Jennifer; de la Haye, Kayla; Barnett, Lisa M; Allender, Steven

    2015-01-01

    There is limited understanding of the association between peer social networks and physical activity (PA), sedentary and screen-related behaviors. This study reports on associations between personal network characteristics and these important health behaviors for early adolescents. Participants were 310 students, aged 11-13 years, from fifteen randomly selected Victorian primary schools (43% response rate). PA and sedentary behaviors were collected via accelerometer and self-report questionnaire, and anthropometric measures via trained researchers. Participants nominated up to fifteen friends, and described the frequency of interaction and perceived activity intensity of these friends. Personal network predictors were examined using regression modelling for PA and sedentary/screen behavior. Perceived activity levels of friends, and friendships with very frequent interaction were associated with outside-of-school PA and/or sedentary/screen time. Differences according to sex were also observed in the association between network characteristics and PA and sedentary time. A higher number of friends and greater proportion of same sex friends were associated with boys engaging in more moderate-to-vigorous PA outside of school hours. PA intensity during school-day breaks was positively associated with having a greater proportion of friends who played sports for girls, and a greater proportion of male friends for boys. Friendship network characteristics are associated with PA and sedentary/screen time in late childhood/early adolescence, and these associations differ by sex. The positive influence of very active peers may be a promising avenue to strengthen traditional interventions for the promotion of PA and reduction in screen time.

  15. Performance of Group Communication Over Ad-Hoc Networks

    National Research Council Canada - National Science Library

    Mosko, Marc; Garcia-Luna-Aceves, J. J

    2002-01-01

    ... through a network of cluster trees, where a spanning tree joins groups of fully connected nodes. Through numerical analysis and simulations in GloMoSim, we show throughput, goodput, and loss rates for reliable and unreliable networks...

  16. modeling the effect of bandwidth allocation on network performance

    African Journals Online (AJOL)

    Using MATLAB, simulations were then .... of the network resource. Network bandwidth design, simulation, and management ... encoder processes longer signal data blocks, which entails longer ... c is the modulated signal carrier. However, the ...

  17. VMware vSphere performance designing CPU, memory, storage, and networking for performance-intensive workloads

    CERN Document Server

    Liebowitz, Matt; Spies, Rynardt

    2014-01-01

    Covering the latest VMware vSphere software, an essential book aimed at solving vSphere performance problems before they happen VMware vSphere is the industry's most widely deployed virtualization solution. However, if you improperly deploy vSphere, performance problems occur. Aimed at VMware administrators and engineers and written by a team of VMware experts, this resource provides guidance on common CPU, memory, storage, and network-related problems. Plus, step-by-step instructions walk you through techniques for solving problems and shed light on possible causes behind the problems. Divu

  18. Social networks, geographic proximity, and firm performance in Viet Nam

    OpenAIRE

    Howard, Emma

    2017-01-01

    This paper uses panel data to assess the relative importance of social networks and geographic proximity to micro, small, and medium enterprises in Viet Nam. The results suggest that a larger social network, and hiring employees mainly through social networks, are both correlated with higher value added per worker. The number of government officials and civil servants in a firm's network emerges as particularly important. When the quality of contacts is controlled for, firms with tighter soci...

  19. Performance Analysis on the Coexistence of Multiple Cognitive Radio Networks

    Science.gov (United States)

    2015-05-28

    etc. The regulation of wireless networks is done by government agencies through which spectrum is allocated to a particular application , this kind of...Local Area Networks ( WLAN ), cordless phones and BluetoothWireless Personal Area Networks (WPAN). While unlicensed bands have opened up avenues for the...they can be applied to other types of wireless ad hoc networks. As an example, this framework finds application in Device-to-Device (D2D) communication

  20. Bridging Social Circles: Need for Cognition, Prejudicial Judgments, and Personal Social Network Characteristics

    Directory of Open Access Journals (Sweden)

    Petru L. Curşeu

    2017-07-01

    Full Text Available Various factors pertaining to the social context (availability of plausible social contacts as well as personality traits influence the emergence of social ties that ultimately compose one’s personal social network. We build on a situational selection model to argue that personality traits influence the cognitive processing of social cues that in turn influences the preference for particular social ties. More specifically, we use a cross-lagged design to test a mediation model explaining the effects of need for cognition (NFC on egocentric network characteristics. We used the data available in the LISS panel, in which a probabilistic sample of Dutch participants were asked to fill in surveys annually. We tested our model on data collected in three successive years and our results show that people scoring high in NFC tend to revolve in information-rich egocentric networks, characterized by high demographic diversity, high interpersonal dissimilarity, and high average education. The results also show that the effect of NFC on social network characteristics is mediated by non-prejudicial judgments.

  1. Social Networks Use, Loneliness and Academic Performance among University Students

    Science.gov (United States)

    Stankovska, Gordana; Angelkovska, Slagana; Grncarovska, Svetlana Pandiloska

    2016-01-01

    The world is extensively changed by Social Networks Sites (SNSs) on the Internet. A large number of children and adolescents in the world have access to the internet and are exposed to the internet at a very early age. Most of them use the Social Networks Sites with the purpose of exchanging academic activities and developing a social network all…

  2. Job Search, Networks, and Labor Market Performance of Immigrants

    OpenAIRE

    Arceo-Gómez, Eva Olimpia

    2012-01-01

    We develop an on-the-job search model in which immigrants search for jobs through formal channels or networks, and the quality of job offers differs across search methods. The model predicts networks unambiguously lead to a larger share of network jobs in job-to-job transitions, whereas the effect is ambiguous in unemployment-to-job transitions.

  3. Performance Analysis of Space Information Networks with Backbone Satellite Relaying for Vehicular Networks

    Directory of Open Access Journals (Sweden)

    Jian Jiao

    2017-01-01

    Full Text Available Space Information Network (SIN with backbone satellites relaying for vehicular network (VN communications is regarded as an effective strategy to provide diverse vehicular services in a seamless, efficient, and cost-effective manner in rural areas and highways. In this paper, we investigate the performance of SIN return channel cooperative communications via an amplify-and-forward (AF backbone satellite relaying for VN communications, where we assume that both of the source-destination and relay-destination links undergo Shadowed-Rician fading and the source-relay link follows Rician fading, respectively. In this SIN-assisted VN communication scenario, we first obtain the approximate statistical distributions of the equivalent end-to-end signal-to-noise ratio (SNR of the system. Then, we derive the closed-form expressions to efficiently evaluate the average symbol error rate (ASER of the system. Furthermore, the ASER expressions are taking into account the effect of satellite perturbation of the backbone relaying satellite, which reveal the accumulated error of the antenna pointing error. Finally, simulation results are provided to verify the accuracy of our theoretical analysis and show the impact of various parameters on the system performance.

  4. Performance Evaluation of Moving Small-Cell Network with Proactive Cache

    Directory of Open Access Journals (Sweden)

    Young Min Kwon

    2016-01-01

    Full Text Available Due to rapid growth in mobile traffic, mobile network operators (MNOs are considering the deployment of moving small-cells (mSCs. mSC is a user-centric network which provides voice and data services during mobility. mSC can receive and forward data traffic via wireless backhaul and sidehaul links. In addition, due to the predictive nature of users demand, mSCs can proactively cache the predicted contents in off-peak-traffic periods. Due to these characteristics, MNOs consider mSCs as a cost-efficient solution to not only enhance the system capacity but also provide guaranteed quality of service (QoS requirements to moving user equipment (UE in peak-traffic periods. In this paper, we conduct extensive system level simulations to analyze the performance of mSCs with varying cache size and content popularity and their effect on wireless backhaul load. The performance evaluation confirms that the QoS of moving small-cell UE (mSUE notably improves by using mSCs together with proactive caching. We also show that the effective use of proactive cache significantly reduces the wireless backhaul load and increases the overall network capacity.

  5. The Impact of Message Replication on the Performance of Opportunistic Networks for Sensed Data Collection

    Directory of Open Access Journals (Sweden)

    Tekenate E. Amah

    2017-11-01

    Full Text Available Opportunistic networks (OppNets provide a scalable solution for collecting delay‑tolerant data from sensors for their respective gateways. Portable handheld user devices contribute significantly to the scalability of OppNets since their number increases according to user population and they closely follow human movement patterns. Hence, OppNets for sensed data collection are characterised by high node population and degrees of spatial locality inherent to user movement. We study the impact of these characteristics on the performance of existing OppNet message replication techniques. Our findings reveal that the existing replication techniques are not specifically designed to cope with these characteristics. This raises concerns regarding excessive message transmission overhead and throughput degradations due to resource constraints and technological limitations associated with portable handheld user devices. Based on concepts derived from the study, we suggest design guidelines to augment existing message replication techniques. We also follow our design guidelines to propose a message replication technique, namely Locality Aware Replication (LARep. Simulation results show that LARep achieves better network performance under high node population and degrees of spatial locality as compared with existing techniques.

  6. An investigation of 'sparse channel networks'. Characteristic behaviours and their causes

    Energy Technology Data Exchange (ETDEWEB)

    Black, J.H. (In Situ Solutions, East Bridgford (GB)); Barker, J.A.; Woodman, N.D. (Univ. of Southampton (GB))

    2007-09-15

    This report represents a third study in a series concerned with groundwater flow in poorly permeable fractured crystalline rocks. The study has brought together three linked, but distinct, elements; a mathematical analysis of the intersection of ellipses, a review of field measurements associated with nuclear waste repository investigations and probabilistic simulations using a lattice network numerical model. We conclude that the model of channels that traverse fracture intersections without necessarily branching is a very likely representation of reality. More generally, assembling all the lines of evidence, it is suggested that groundwater flow systems in fractured crystalline rocks in the environs of underground laboratories have the following characteristics: Groundwater flows within a sparse network of channels just above the percolation limit. The frequency of intersections is low in that individual channels extend considerable distances between significant junctions. Individual channels often extend over many fracture surfaces and the resulting flow system is only weakly related to the density or size of mappable fractures. The sparseness of systems compared to the size of drifts and tunnels means that only a very few flow channels are intersected by drifts and tunnels. Highly convergent flow is required to connect to the rest of the network and this is misinterpreted as a skin of low hydraulic conductivity. Systems are so sparse that they are controlled by a few 'chokes' that give rise to compartments of head, and probably, of groundwater chemistry. Channels occur on all fracture planes, including those within fracture zones, and although the characteristics of the fracture zone channel networks may differ from those in surrounding rocks, they are nonetheless still channel networks. The actively flowing sparse channel network, occurring within any particular rock, is a naturally selected, small sub-set of the available channels. Hence, there are

  7. An investigation of 'sparse channel networks'. Characteristic behaviours and their causes

    International Nuclear Information System (INIS)

    Black, J.H.; Barker, J.A.; Woodman, N.D.

    2007-09-01

    This report represents a third study in a series concerned with groundwater flow in poorly permeable fractured crystalline rocks. The study has brought together three linked, but distinct, elements; a mathematical analysis of the intersection of ellipses, a review of field measurements associated with nuclear waste repository investigations and probabilistic simulations using a lattice network numerical model. We conclude that the model of channels that traverse fracture intersections without necessarily branching is a very likely representation of reality. More generally, assembling all the lines of evidence, it is suggested that groundwater flow systems in fractured crystalline rocks in the environs of underground laboratories have the following characteristics: Groundwater flows within a sparse network of channels just above the percolation limit. The frequency of intersections is low in that individual channels extend considerable distances between significant junctions. Individual channels often extend over many fracture surfaces and the resulting flow system is only weakly related to the density or size of mappable fractures. The sparseness of systems compared to the size of drifts and tunnels means that only a very few flow channels are intersected by drifts and tunnels. Highly convergent flow is required to connect to the rest of the network and this is misinterpreted as a skin of low hydraulic conductivity. Systems are so sparse that they are controlled by a few 'chokes' that give rise to compartments of head, and probably, of groundwater chemistry. Channels occur on all fracture planes, including those within fracture zones, and although the characteristics of the fracture zone channel networks may differ from those in surrounding rocks, they are nonetheless still channel networks. The actively flowing sparse channel network, occurring within any particular rock, is a naturally selected, small sub-set of the available channels. Hence, there are many

  8. Can Knowledge of the Characteristics of "High Performers" Be Generalised?

    Science.gov (United States)

    McKenna, Stephen

    2002-01-01

    Two managers described as high performing constructed complexity maps of their organization/world. The maps suggested that high performance is socially constructed and negotiated in specific contexts and management competencies associated with it are context specific. Development of high performers thus requires personalized coaching more than…

  9. Rail gun performance and plasma characteristics due to wall ablation

    Science.gov (United States)

    Ray, P. K.

    1986-01-01

    The experiment of Bauer, et al. (1982) is analyzed by considering wall ablation and viscous drag in the plasma. Plasma characteristics are evaluated through a simple fluid-mechanical analysis considering only wall ablation. By equating the energy dissipated in the plasma with the radiation heat loss, the average properties of the plasma are determined as a function of time.

  10. Growth performance and carcass characteristics of three Ethiopian ...

    African Journals Online (AJOL)

    Breed affected the weights of internal fat depots. The findings indicate that breed affected the carcass characteristics of the three Ethiopian goat breeds. Keywords: Indigenous goats; carcass yield; carcass composition; primal cuts; non-carcass components. South African Journal of Animal Science Vol. 37 (4) 2007: pp.221- ...

  11. Hearing Instrument using receivers with different performance characteristics

    DEFF Research Database (Denmark)

    2009-01-01

    The invention regards a signal processing device in a hearing aid, wherein the signal processing device is electrically coupled to a connection socket operable to detachably connect a receiver to the socket and whereby the signal processing device further comprise a detector operable to detect...... a characteristics of the receiver which is connected to the signal processing device through the connection socket....

  12. Design and performance characteristics of a krypton chloride (λ ...

    Indian Academy of Sciences (India)

    2014-01-07

    Jan 7, 2014 ... Development of a discharge-pumped krypton chloride (KrCl) laser operating at 222 nm wavelength is demonstrated. In this paper the design, successful realization and operating characteristics of KrCl excimer laser are reported. The laser is driven by a simple and efficient excitation technique using ...

  13. Performance of sampling methods to estimate log characteristics for wildlife.

    Science.gov (United States)

    Lisa J. Bate; Torolf R. Torgersen; Michael J. Wisdom; Edward O. Garton

    2004-01-01

    Accurate estimation of the characteristics of log resources, or coarse woody debris (CWD), is critical to effective management of wildlife and other forest resources. Despite the importance of logs as wildlife habitat, methods for sampling logs have traditionally focused on silvicultural and fire applications. These applications have emphasized estimates of log volume...

  14. performance characteristics of an armature voltage controlled dc motor

    African Journals Online (AJOL)

    Dr Obe

    obtained by digital computer analysis. The results show that closed loop operation, with appropriate control ... Using digital computer analysis, the driver characteristics of a test motor is investigated. In the closed loop ... system circuit failure especially with respect to the semiconductor devices that may be used in varying ...

  15. Performance Evaluation of Resilience using Service Relocation for GMPLS Networks

    DEFF Research Database (Denmark)

    Wessing, Henrik; Herrmann, Sven; Ruepp, Sarah Renée

    2015-01-01

    Cloud computing today represents an ever increasing part of the data exchanged over the Internet. This influences the core network, where the special properties of cloud based services can be leveraged to increase the network efficiency. This paper explores the concept of relocation for the backup...... path when providing resiliency to cloud services in the network. The control plane of a GMPLSenabled optical network is simulated, thus evaluating the proposed Path Computation Element architecture for service relocation. The results show that for increased offered traffic in the network, the overall...

  16. Effects of Network Characteristics on Reaching the Payoff-Dominant Equilibrium in Coordination Games: A Simulation study.

    Science.gov (United States)

    Buskens, Vincent; Snijders, Chris

    2016-01-01

    We study how payoffs and network structure affect reaching the payoff-dominant equilibrium in a [Formula: see text] coordination game that actors play with their neighbors in a network. Using an extensive simulation analysis of over 100,000 networks with 2-25 actors, we show that the importance of network characteristics is restricted to a limited part of the payoff space. In this part, we conclude that the payoff-dominant equilibrium is chosen more often if network density is larger, the network is more centralized, and segmentation of the network is smaller. Moreover, it is more likely that heterogeneity in behavior persists if the network is more segmented and less centralized. Persistence of heterogeneous behavior is not related to network density.

  17. Understanding characteristics in multivariate traffic flow time series from complex network structure

    Science.gov (United States)

    Yan, Ying; Zhang, Shen; Tang, Jinjun; Wang, Xiaofei

    2017-07-01

    Discovering dynamic characteristics in traffic flow is the significant step to design effective traffic managing and controlling strategy for relieving traffic congestion in urban cities. A new method based on complex network theory is proposed to study multivariate traffic flow time series. The data were collected from loop detectors on freeway during a year. In order to construct complex network from original traffic flow, a weighted Froenius norm is adopt to estimate similarity between multivariate time series, and Principal Component Analysis is implemented to determine the weights. We discuss how to select optimal critical threshold for networks at different hour in term of cumulative probability distribution of degree. Furthermore, two statistical properties of networks: normalized network structure entropy and cumulative probability of degree, are utilized to explore hourly variation in traffic flow. The results demonstrate these two statistical quantities express similar pattern to traffic flow parameters with morning and evening peak hours. Accordingly, we detect three traffic states: trough, peak and transitional hours, according to the correlation between two aforementioned properties. The classifying results of states can actually represent hourly fluctuation in traffic flow by analyzing annual average hourly values of traffic volume, occupancy and speed in corresponding hours.

  18. The impacts of network competence, knowledge sharing on service innovation performance: Moderating role of relationship quality

    Directory of Open Access Journals (Sweden)

    Zaoquan Jian

    2013-03-01

    Full Text Available Purpose: To examine how network competence, knowledge sharing and relationship quality affect service innovation performanceDesign/methodology/approach: Empirical ResearchFindings: 1 Both enterprise’s network competence and knowledge sharing have distinct positive impact on SIP; (2 Knowledge sharing partially mediates the effect of network competence on SIP. (3 Relationship quality positively moderates the effect of network competence on knowledge sharing, and the effect of knowledge sharing on SIP. (4 Relationship quality does not positively moderate the effect of network competence on SIP.Originality/value: This study has enriched current understanding of the relationship among network competence, knowledge sharing, relationship quality and service innovation performance.

  19. Key demands and characteristics of occupations performed by individuals with spinal cord injury living in Switzerland.

    Science.gov (United States)

    Nützi, M; Trezzini, B; Ronca, E; Schwegler, U

    2017-08-08

    Descriptive qualitative and quantitative study using cross-sectional data from the Swiss Spinal Cord Injury Cohort Study (SwiSCI). To determine the key demands and characteristics of occupations performed by individuals with spinal cord injury (SCI). Swiss community. Job titles indicated by SwiSCI participants were linked to occupational titles from the Occupational Information Network (O*NET) and then frequency-analyzed across sociodemographic and injury-related factors. Subsequently, average O*NET relevance values ranging from 0 to 100 were calculated for the occupations' demands and characteristics, both in general and stratified by injury-related factors. The 1549 study participants indicated a total of 717 job titles and were primarily employed in administrative and management occupations (22.1% and 16.4%, respectively). The participants' occupations predominantly required verbal abilities (average relevance [AR]=68.4) and complex problem solving skills (AR=55.8) and were characterized by conventional work tasks (AR=62.9) and social relationships (AR=58.6). Both the occupations' frequency distribution as well as the average relevance levels of their demands and characteristics differed by SCI severity. Individuals with SCI perform a broad range of occupations that are mainly characterized by cognitive and communicative demands, while physical demands are of minor importance. By informing the development of job matching profiles for vocational guidance, our study facilitates the determination of well-matching jobs for persons with SCI and may contribute to a more sustainable return to work of the affected persons.Spinal Cord advance online publication, 8 August 2017; doi:10.1038/sc.2017.84.

  20. Wireless sensor network performance metrics for building applications

    Energy Technology Data Exchange (ETDEWEB)

    Jang, W.S. (Department of Civil Engineering Yeungnam University 214-1 Dae-Dong, Gyeongsan-Si Gyeongsangbuk-Do 712-749 South Korea); Healy, W.M. [Building and Fire Research Laboratory, 100 Bureau Drive, Gaithersburg, MD 20899-8632 (United States)

    2010-06-15

    Metrics are investigated to help assess the performance of wireless sensors in buildings. Wireless sensor networks present tremendous opportunities for energy savings and improvement in occupant comfort in buildings by making data about conditions and equipment more readily available. A key barrier to their adoption, however, is the uncertainty among users regarding the reliability of the wireless links through building construction. Tests were carried out that examined three performance metrics as a function of transmitter-receiver separation distance, transmitter power level, and obstruction type. These tests demonstrated, via the packet delivery rate, a clear transition from reliable to unreliable communications at different separation distances. While the packet delivery rate is difficult to measure in actual applications, the received signal strength indication correlated well with the drop in packet delivery rate in the relatively noise-free environment used in these tests. The concept of an equivalent distance was introduced to translate the range of reliability in open field operation to that seen in a typical building, thereby providing wireless system designers a rough estimate of the necessary spacing between sensor nodes in building applications. It is anticipated that the availability of straightforward metrics on the range of wireless sensors in buildings will enable more widespread sensing in buildings for improved control and fault detection. (author)

  1. MANAGEMENT TEAM CHARACTERISTICS: EVIDENCE FROM UNIVERSITY GOVERNANCE AND SCHOOL PERFORMANCE

    OpenAIRE

    Hsiang-Tsai Chiang; Mei-Chih Lin

    2013-01-01

    The paper examines cognition from the viewpoint of internal management teams of private universities against satisfaction with school performance, applying the SEM model. Empirical results show that the board’s operational effectiveness and attendance rate for internal important meetings held on campus have a significantly positive relationship with implementing effectiveness and satisfaction with school administrative performance. The satisfaction with school administrative performance and...

  2. Study on team characteristics influencing on nuclear safety culture in Korea based on Bayesian networks

    Energy Technology Data Exchange (ETDEWEB)

    Young-gab, K.; Chan-ho, S.; Jeong-jin, P., E-mail: iamkyg@khnp.co.kr, E-mail: chsung@khnp.co.kr, E-mail: jjpark82@khnp.co.kr [Korea Hydro & Nuclear Power Co., Central Research Inst., Yuseong-gu, Daejeon (Korea, Republic of)

    2014-07-01

    The safety culture of Korean nuclear power plants has been settled down as an organizational culture since the Chernobyl accident in 1986. Reason (1997) proposed that safety culture is a sub-culture of corporate culture and sub-culture is a term that can be used interchangeably to a sub-group of people (i.e., department, workgroup). Therefore, the safety culture of organization comprised of various teams can be told as a culture to reflect team characteristics and interact with each other. Team characteristics have something to do with a successful task performance and task efficiency. However, the team characteristics in nuclear power plant have to consider safety preferentially rather than performance. Team characteristics for a safety are necessary to ensure and enhance the safety of safety-critical system. This paper proposed team characteristics for a safety which influence on the strong and vulnerable area of safety culture. These characteristics were analyzed on the basis of the safety culture evaluation which was performed to measure the level of plant workers' safety culture in 2013. The model of team characteristics was constructed considering Bayesian inference and the result was proposed according to workers' awareness. Safety team characteristics have a direct or indirect effect on the safety of nuclear power plants. Therefore, if they are improved and trained continuously, the safety of nuclear power plants might be enhanced. (author)

  3. Study on team characteristics influencing on nuclear safety culture in Korea based on Bayesian networks

    International Nuclear Information System (INIS)

    Young-gab, K.; Chan-ho, S.; Jeong-jin, P.

    2014-01-01

    The safety culture of Korean nuclear power plants has been settled down as an organizational culture since the Chernobyl accident in 1986. Reason (1997) proposed that safety culture is a sub-culture of corporate culture and sub-culture is a term that can be used interchangeably to a sub-group of people (i.e., department, workgroup). Therefore, the safety culture of organization comprised of various teams can be told as a culture to reflect team characteristics and interact with each other. Team characteristics have something to do with a successful task performance and task efficiency. However, the team characteristics in nuclear power plant have to consider safety preferentially rather than performance. Team characteristics for a safety are necessary to ensure and enhance the safety of safety-critical system. This paper proposed team characteristics for a safety which influence on the strong and vulnerable area of safety culture. These characteristics were analyzed on the basis of the safety culture evaluation which was performed to measure the level of plant workers' safety culture in 2013. The model of team characteristics was constructed considering Bayesian inference and the result was proposed according to workers' awareness. Safety team characteristics have a direct or indirect effect on the safety of nuclear power plants. Therefore, if they are improved and trained continuously, the safety of nuclear power plants might be enhanced. (author)

  4. A New Processing Method Combined with BP Neural Network for Francis Turbine Synthetic Characteristic Curve Research

    Directory of Open Access Journals (Sweden)

    Junyi Li

    2017-01-01

    Full Text Available A BP (backpropagation neural network method is employed to solve the problems existing in the synthetic characteristic curve processing of hydroturbine at present that most studies are only concerned with data in the high efficiency and large guide vane opening area, which can hardly meet the research requirements of transition process especially in large fluctuation situation. The principle of the proposed method is to convert the nonlinear characteristics of turbine to torque and flow characteristics, which can be used for real-time simulation directly based on neural network. Results show that obtained sample data can be extended successfully to cover working areas wider under different operation conditions. Another major contribution of this paper is the resampling technique proposed in the paper to overcome the limitation to sample period simulation. In addition, a detailed analysis for improvements of iteration convergence of the pressure loop is proposed, leading to a better iterative convergence during the head pressure calculation. Actual applications verify that methods proposed in this paper have better simulation results which are closer to the field and provide a new perspective for hydroturbine synthetic characteristic curve fitting and modeling.

  5. Rumor diffusion in heterogeneous networks by considering the individuals' subjective judgment and diverse characteristics

    Science.gov (United States)

    Ma, Jing; Zhu, He

    2018-06-01

    In this study, we propose a novel rumor spreading model in consideration of the individuals' subjective judgment and diverse characteristics. To reflect the diversity of the individuals' characteristics, we introduce two probability distribution functions, which could be chosen arbitrarily or given by empirical data, to characterize individuals' mastering degree of knowledge with respect to the domain of a specific rumor and individuals' rationality degree. Different from existing models, no two persons in our model are identical, and each individual can judge the authenticity of the information, e.g., rumors, with his distinctive characteristics. In addition, by means of the mean-field method, we establish the expression of the dynamics of the rumor propagation in the complex heterogeneous networks and derive the rumor spreading threshold. Through the theoretical analysis, we find that the threshold is independent of the forms of the two introduced functions. Furthermore, we prove the stability of the rumor-free equilibrium set E0. That is if and only if R0 series of numerical simulations to verify the theoretical results and comprehensively illustrate the evolution of the model. The simulation results show that because of the diversity of individuals' characteristics, it becomes more difficult for the rumor to disseminate in the networks and the higher the mean of knowledge and the mean of rationality are, the more time it will take for the model to evolve to the steady state.

  6. Effects of dehydration methods on the characteristics of fibrous networks from un-tanned hides

    Science.gov (United States)

    To improve prospective markets and to secure a viable future for the hides and leather industries, it is important to develop new uses and novel biobased products from hides. We hypothesize collagen fiber networks derived from un-tanned hides can be utilized to prepare high performance green compos...

  7. Effects of dehydration methods on characteristics of fibrous networks from un-tanned hides

    Science.gov (United States)

    To improve prospective markets and to secure a viable future for the hides and leather industries, it is important to develop new uses and novel biobased products from hides. We hypothesize collagen fiber networks derived from un-tanned hides can be utilized to prepare high performance green compos...

  8. Effect of landslides on the structural characteristics of land-cover based on complex networks

    Science.gov (United States)

    He, Jing; Tang, Chuan; Liu, Gang; Li, Weile

    2017-09-01

    Landslides have been widely studied by geologists. However, previous studies mainly focused on the formation of landslides and never considered the effect of landslides on the structural characteristics of land-cover. Here we define the modeling of the graph topology for the land-cover, using the satellite images of the earth’s surface before and after the earthquake. We find that the land-cover network satisfies the power-law distribution, whether the land-cover contains landslides or not. However, landslides may change some parameters or measures of the structural characteristics of land-cover. The results show that the linear coefficient, modularity and area distribution are all changed after the occurence of landslides, which means the structural characteristics of the land-cover are changed.

  9. Common Characteristics of Good and Poorly Performing AC Pavements

    Science.gov (United States)

    1999-12-01

    This report documents the analysis and findings of a study to identify the site conditions and design/construction features of : flexible pavements that lead to good performance and those that lead to poor performance. Data from the Long Term Pavemen...

  10. Common Characteristics of Good and Poorly Performing PCC Pavements

    Science.gov (United States)

    1998-01-01

    This report documents the analysis and findings of a study to identify the site conditions and design/construction features of concrete pavements (JPCP, JRCP, CRCP) that lead to good performance and those that lead to poor performance. Data from Long...

  11. Variability of Performance: A "Signature" Characteristic of Learning Disabled Children?

    Science.gov (United States)

    Fuchs, Douglas; And Others

    Two studies were conducted to compare the performance instability of children (grades 3-9) labeled learning disabled/brain injured (LD/BI) to the performance instability of emotionally handicapped (EH) children. In the first study, 50 LD/BI and 37 EH students were measured on three third grade reading passages twice, once within one sitting and…

  12. Poor physician performance in the Netherlands: characteristics, causes, and prevalence.

    NARCIS (Netherlands)

    Goor, M.M.P.G. van den; Wagner, C.; Lombarts, K.M.J.M.H.

    2015-01-01

    Introduction: Poor physician performance has a profound impact on patient safety and society's trust in the health care system. The attention that this topic has received in the media suggests that it is a large-scale issue. However, research about physician performance is still scant; there is

  13. Depression, Smoking, and Ego-Centric Social Network Characteristics in Ohio Appalachian Women.

    Science.gov (United States)

    Lam, Jeffrey; Lu, Bo; Doogan, Nate; Thomson, Tiffany; Ferketich, Amy; Paskett, Electra D; Wewers, Mary Ellen

    2017-01-01

    Depression is a serious, costly, and debilitating disorder that is understudied in rural women. Studies show that depression is associated with low social integration and support, but few studies investigate the relationship between depression and social network characteristics. This study examined the associations among women from three Ohio Appalachian counties enrolled in a health study, which aimed to collect information for a future social network smoking cessation intervention. An address-based sampling method was used to randomly select and recruit 404 women. A cross-sectional survey and interview were used to collect information about demographic, psychosocial, behavioral factors, and ego-centric social network characteristics, which are variables derived from an individual (ego) and her first degree contacts (alters). The CES-D scale assessed depressive symptoms. A multivariable logistic regression analysis described the association between these factors and participants with depression (defined as CES-D≥16). Higher network density, or greater number of relationships among alters divided by the total amount of alters, reduced the risk for depression (OR = 0.84, 95% confidence interval [CI] 0.73-0.95). Additionally, women with a high percentage of smoking alters were at greater risk for depression (OR = 1.19, 95% CI 1.02-1.39). Other factors associated with risk for depression included perceived stress score (OR = 1.34, 95% CI 1.24-1.45), loneliness score (OR = 1.37, 95% CI 1.05-1.80), and days with poor physical health (OR = 1.06, 95% CI 1.02-1.11). Findings suggest that psychosocial factors and social networks should be considered when addressing depression in clinical practice.

  14. Assessing the implications of cellular network performance on mobile content access

    DEFF Research Database (Denmark)

    Kaup, Fabian; Michelinakis, Foivos; Bui, Nicola

    2016-01-01

    Mobile applications such as VoIP, (live) gaming, or video streaming have diverse QoS requirements ranging from low delay to high throughput. The optimization of the network quality experienced by end-users requires detailed knowledge of the expected network performance. Also, the achieved service...... of cellular network measurements, focused on analyzing root causes of mobile network performance variability. Measurements conducted on a 4G cellular network in Germany show that management and configuration decisions have a substantial impact on the performance. Specifically, it is observed...

  15. Is functional integration of resting state brain networks an unspecific biomarker for working memory performance?

    Science.gov (United States)

    Alavash, Mohsen; Doebler, Philipp; Holling, Heinz; Thiel, Christiane M; Gießing, Carsten

    2015-03-01

    Is there one optimal topology of functional brain networks at rest from which our cognitive performance would profit? Previous studies suggest that functional integration of resting state brain networks is an important biomarker for cognitive performance. However, it is still unknown whether higher network integration is an unspecific predictor for good cognitive performance or, alternatively, whether specific network organization during rest predicts only specific cognitive abilities. Here, we investigated the relationship between network integration at rest and cognitive performance using two tasks that measured different aspects of working memory; one task assessed visual-spatial and the other numerical working memory. Network clustering, modularity and efficiency were computed to capture network integration on different levels of network organization, and to statistically compare their correlations with the performance in each working memory test. The results revealed that each working memory aspect profits from a different resting state topology, and the tests showed significantly different correlations with each of the measures of network integration. While higher global network integration and modularity predicted significantly better performance in visual-spatial working memory, both measures showed no significant correlation with numerical working memory performance. In contrast, numerical working memory was superior in subjects with highly clustered brain networks, predominantly in the intraparietal sulcus, a core brain region of the working memory network. Our findings suggest that a specific balance between local and global functional integration of resting state brain networks facilitates special aspects of cognitive performance. In the context of working memory, while visual-spatial performance is facilitated by globally integrated functional resting state brain networks, numerical working memory profits from increased capacities for local processing

  16. The Influence of Social Network Characteristics on Peer Clustering in Smoking: A Two-Wave Panel Study of 19- and 23-Year-Old Swedes.

    Science.gov (United States)

    Miething, Alexander; Rostila, Mikael; Edling, Christofer; Rydgren, Jens

    2016-01-01

    The present study examines how the composition of social networks and perceived relationship content influence peer clustering in smoking, and how the association changes during the transition from late adolescence to early adulthood. The analysis was based on a Swedish two-wave survey sample comprising ego-centric network data. Respondents were 19 years old in the initial wave, and 23 when the follow-up sample was conducted. 17,227 ego-alter dyads were included in the analyses, which corresponds to an average response rate of 48.7 percent. Random effects logistic regression models were performed to calculate gender-specific average marginal effects of social network characteristics on smoking. The association of egos' and alters' smoking behavior was confirmed and found to be stronger when correlated in the female sample. For females, the associations decreased between age 19 and 23. Interactions between network characteristics and peer clustering in smoking showed that intense social interactions with smokers increase egos' smoking probability. The influence of network structures on peer clustering in smoking decreased during the transition from late adolescence to early adulthood. The study confirmed peer clustering in smoking and revealed that females' smoking behavior in particular is determined by social interactions. Female smokers' propensity to interact with other smokers was found to be associated with the quality of peer relationships, frequent social interactions, and network density. The influence of social networks on peer clustering in smoking decreased during the transition from late adolescence to early adulthood.

  17. Improving the performance of neutral network in differentiation of breast tumors using wavelet transformation on dynamic MRI

    International Nuclear Information System (INIS)

    Abdolmaleki, P.; Abrishami-Moghddam, H.; Gity, M.; Mokhtari- Dizaji, M.; Mostafa, A.

    2005-01-01

    A computer aided diagnosis system was established using the wavelet transform and neural network to differentiate malignant from benign in a group of patients with histo-pathologically proved breast lesions based on the data derived independently from time-intensity profile. Materials and Methods: The performance of the artificial neural network was evaluated using a database with 105 patients' records each of which consisted of 8 quantitative parameters mostly derived from time- intensity profile using wavelet transform. These findings were encoded as features for a three-layered neural network to predict the outcome of biopsy. The network was trained and tested using the jackknife method and its performance was then compared to that of the radiologists in terms of sensitivity, specificity and accuracy using receiver operating characteristic curve (ROC) analysis. Results: The network was able to classify correctly the 84 original cases and yielded a comparable diagnostic accuracy (80%), compared to that of the radiologist (85%) by performing a constructive association between extracted quantitative data and corresponding pathological results (r=0.63, p<0.001). Conclusion: An artificial neural network supported by wavelet transform can be trained to differentiate malignant from benign breast tumors with a reasonable degree of accuracy

  18. Performance Analysis with Network-Enhanced Complexities: On Fading Measurements, Event-Triggered Mechanisms, and Cyber Attacks

    Directory of Open Access Journals (Sweden)

    Derui Ding

    2014-01-01

    Full Text Available Nowadays, the real-world systems are usually subject to various complexities such as parameter uncertainties, time-delays, and nonlinear disturbances. For networked systems, especially large-scale systems such as multiagent systems and systems over sensor networks, the complexities are inevitably enhanced in terms of their degrees or intensities because of the usage of the communication networks. Therefore, it would be interesting to (1 examine how this kind of network-enhanced complexities affects the control or filtering performance; and (2 develop some suitable approaches for controller/filter design problems. In this paper, we aim to survey some recent advances on the performance analysis and synthesis with three sorts of fashionable network-enhanced complexities, namely, fading measurements, event-triggered mechanisms, and attack behaviors of adversaries. First, these three kinds of complexities are introduced in detail according to their engineering backgrounds, dynamical characteristic, and modelling techniques. Then, the developments of the performance analysis and synthesis issues for various networked systems are systematically reviewed. Furthermore, some challenges are illustrated by using a thorough literature review and some possible future research directions are highlighted.

  19. Performance ratio hardness characteristics polystyrene-metal composite materials

    International Nuclear Information System (INIS)

    Klepikov, V.F.; Prokhorenko, E.M.; Lytvynenko, V.V.; Zakharchenko, A.A.; Hazhmuradov, M.A.

    2015-01-01

    The methods of measuring the hardness of layered polystyrene-metallic composite materials. It is proposed to use powder-like tungsten and powder-like steel as radiation-protective layer. A measurement of the hardness of composites of different composition, and given its dependence on the particle size and their form. The possibility of increasing the hardness of the composites reinforced with metallic additives. Radiation-protective characteristics were calculated for the studied species of composite materials. Influence of the quantitative composition of the metal components is studied on the change of the absorbed dose of gamma radiation

  20. First comes social networking, then comes marriage? Characteristics of Americans married 2005-2012 who met through social networking sites.

    Science.gov (United States)

    Hall, Jeffrey A

    2014-05-01

    Abstract Although social networking sites (SNS) have become increasingly prevalent and integrated into the lives of users, the role of SNS in courtship is relatively unknown. The present manuscript reports on the characteristics of Americans married between 2005 and 2012 who met through SNS drawn from a weighted national sample (N=18,527). Compared to other online meetings (i.e., dating sites, online communities, one-on-one communication), individuals who met through SNS were younger, married more recently, and were more likely to be African American. Compared with offline meetings, individuals who met through SNS were more likely to be younger, male, African American and Hispanic, married more recently, and frequent Internet users with higher incomes. Trends suggest an increasing proportion of individuals are meeting using SNS, necessitating further research on factors that influence romantic relational development through SNS.

  1. the steady-state performance characteristics of single phase transfer

    African Journals Online (AJOL)

    2012-11-03

    Nov 3, 2012 ... field (SPTF) machine operating in the asynchronous mode from which the performance charac- teristics could be ... motor from a poly-phase induction motor by discon- necting one of its .... tating magnetic field. The pulsating ...

  2. The Importance of External Contacts in Job Performance: A Study in Healthcare Organizations Using Social Network Analysis

    Directory of Open Access Journals (Sweden)

    Pilar Marqués-Sánchez

    2018-06-01

    Full Text Available There is evidence that relations between physicians and nurses within healthcare institutions might be shaped by informal aspects of such relations and by links to people external to the organization, with an impact on work performance. Social network analysis is underutilized in exploring such associations. The paper aims to describe physicians’ and nurses’ relationships outside their clinical units and to explore what kind of ties are related to job performance. A network analysis was performed on cross-sectional data. The study population consisted of 196 healthcare employees working in a public hospital and a primary healthcare centre in Spain. Relational data were analysed using the UCINET software package. Measures included: (i sample characteristics; (ii social network variables; and (iii team performance ratings. Descriptive statistics (means, medians, percentages were used to characterize staff and performance ratings. A correlational analysis was conducted to examine the strength of relationships between four different types of ties. Our findings suggest that external ties only contribute to improving the performance of physicians at both the individual and team level. They are focused on the decision-making process about the therapeutic plan and, therefore, might need to seek advice outside the workplace. In contrast, external ties are not relevant for the work performance of nurses, as they need to find solutions to immediate problems in a short period of time, having strong ties in the workplace. Social network analysis can illuminate relations within healthcare organizations and inform the development of innovative interventions.

  3. IDI diesel engine performance and exhaust emission analysis using biodiesel with an artificial neural network (ANN

    Directory of Open Access Journals (Sweden)

    K. Prasada Rao

    2017-09-01

    Full Text Available Biodiesel is receiving increasing attention each passing day because of its fuel properties and compatibility. This study investigates the performance and emission characteristics of single cylinder four stroke indirect diesel injection (IDI engine fueled with Rice Bran Methyl Ester (RBME with Isopropanol additive. The investigation is done through a combination of experimental data analysis and artificial neural network (ANN modeling. The study used IDI engine experimental data to evaluate nine engine performance and emission parameters including Exhaust Gas Temperature (E.G.T, Brake Specific Fuel Consumption (BSFC, Brake Thermal Efficiency (B.The and various emissions like Hydrocarbons (HC, Carbon monoxide (CO, Carbon dioxide (CO2, Oxygen (O2, Nitrogen oxides (NOX and smoke. For the ANN modeling standard back propagation algorithm was found to be the optimum choice for training the model. A multi-layer perception (MLP network was used for non-linear mapping between the input and output parameters. It was found that ANN was able to predict the engine performance and exhaust emissions with a correlation coefficient of 0.995, 0.980, 0.999, 0.985, 0.999, 0.999, 0.980, 0.999, and 0.999 for E.G.T, BSFC, B.The, HC, O2, CO2, CO, NOX, smoke respectively.

  4. Investigation of transfer characteristics of high performance graphene flakes.

    Science.gov (United States)

    Venugopal, Gunasekaran; Krishnamoorthy, Karthikeyan; Kim, Sang-Jae

    2013-05-01

    In this article, we attempted a study on field effect transport characteristics of graphene flakes. These graphene flakes were exfoliated by mechanical peeling-off technique and the electrical contacts were patterned by photo-lithographic method. Graphene devices have shown better transfer characteristics which was obtained even in low-voltage (graphene transistors were patterned on oxidized silicon wafers. A clear n-type to p-type transition at Dirac point and higher electron drain-current modulation in positive back-gate field with current minimum (the Dirac point) were observed at V(GS) = -1.7 V. The carrier mobility was determined from the measured transconductance. The transconductance of the graphene transistors was observed as high as 18.6 microS with a channel length of 68 microm. A maximum electron mobility of 1870 +/- 143 cm2/V x s and hole mobility of 1050 +/- 35 cm2/V x s were achieved at a drain bias 2.1 V which are comparatively higher values among reported for mechanically exfoliated graphene using lithographic method. The fabricated devices also sustained with high-current density for 40 hr in continuous operation without any change in device resistance, which could be applied for robust wiring applications.

  5. Social network characteristics and cervical cancer screening among Quechua women in Andean Peru

    Directory of Open Access Journals (Sweden)

    John S. Luque

    2016-02-01

    Full Text Available Abstract Background Peru has high cervical cancer incidence and mortality rates compared to other Andean countries. Therefore, partnerships between governmental and international organizations have targeted rural areas of Peru to receive cervical cancer screening via outreach campaigns. Previous studies have found a relationship between a person’s social networks and cancer screening behaviors. Screening outreach campaigns conducted by the nonprofit organization CerviCusco created an opportunity for a social network study to examine cervical cancer screening history and social network characteristics in a rural indigenous community that participated in these campaigns in 2012 and 2013. The aim of this study was to explore social network characteristics in this community related to receipt of cervical cancer screening following the campaigns. Methods An egocentric social network questionnaire was used to collect cross-sectional network data on community participants. Each survey participant (ego was asked to name six other women they knew (alters and identify the nature of their relationship or tie (family, friend, neighbor, other, residential closeness (within 5 km, length of time known, frequency of communication, topics of conversation, and whether they lent money to the person, provided childcare or helped with transportation. In addition, each participant was asked to report the nature of the relationship between all alters identified (e.g., friend, family, or neighbor. Bivariate and multivariate analyses were used to explore the relationship between Pap test receipt at the CerviCusco outreach screening campaigns and social network characteristics. Results Bivariate results found significant differences in percentage of alter composition for neighbors and family, and for mean number of years known, mean density, and mean degree centrality between women who had received a Pap test (n = 19 compared to those who had not (n = 50 (p

  6. Implementation and performance of the ATLAS pixel clustering neural networks

    CERN Document Server

    Gagnon, Louis-Guillaume; The ATLAS collaboration

    2018-01-01

    The high particle densities produced by the Large Hadron Collider (LHC) mean that in the ATLAS pixel detector the clusters of deposited charge start to merge. A neural network-based approach is used to estimate the number of particles contributing to each cluster, and to accurately estimate the hit positions even in the presence of multiple particles. This talk thoroughly describes the algorithm and its implementation as well as present a set of benchmark performance measurements. The problem is most acute in the core of high-momentum jets where the average separation between particles becomes comparable to the detector granularity. This is further complicated by the high number of interactions per bunch crossing. Both these issues will become worse as the Run 3 and HL-LHC programme require analysis of higher and higher pT jets, while the interaction multiplicity rises. Future prospects in the context of LHC Run 3 and the upcoming ATLAS inner detector upgrade are also discussed.

  7. Performance and energy efficiency in wireless self-organized networks

    Energy Technology Data Exchange (ETDEWEB)

    Gao, C.

    2009-07-01

    Self-organized packet radio networks (ad-hoc networks) and wireless sensor networks have got massive attention recently. One of critical problems in such networks is the energy efficiency, because wireless nodes are usually powered by battery. Energy efficiency design can dramatically increase the survivability and stability of wireless ad-hoc/sensor networks. In this thesis the energy efficiency has been considered at different protocol layers for wireless ad-hoc/sensor networks. The energy consumption of wireless nodes is inspected at the physical layer and MAC layer. At the network layer, some current routing protocols are compared and special attention has been paid to reactive routing protocols. A minimum hop analysis is given and according to the analysis result, a modification of AODV routing is proposed. A variation of transmit power can be also applied to clustering algorithm, which is believed to be able to control the scalability of network. Clustering a network can also improve the energy efficiency. We offer a clustering scheme based on the link state measurement and variation of transmit power of intra-cluster and inter-cluster transmission. Simulation shows that it can achieve both targets. In association with the clustering algorithm, a global synchronization scheme is proposed to increase the efficiency of clustering algorithm. The research attention has been also paid to self-organization for multi-hop cellular networks. A 2-hop 2-slot uplink proposal to infrastructure-based cellular networks. The proposed solution can significantly increase the throughput of uplink communication and reduce the energy consumption of wireless terminals. (orig.)

  8. Battery Performance Modelling ad Simulation: a Neural Network Based Approach

    Science.gov (United States)

    Ottavianelli, Giuseppe; Donati, Alessandro

    2002-01-01

    This project has developed on the background of ongoing researches within the Control Technology Unit (TOS-OSC) of the Special Projects Division at the European Space Operations Centre (ESOC) of the European Space Agency. The purpose of this research is to develop and validate an Artificial Neural Network tool (ANN) able to model, simulate and predict the Cluster II battery system's performance degradation. (Cluster II mission is made of four spacecraft flying in tetrahedral formation and aimed to observe and study the interaction between sun and earth by passing in and out of our planet's magnetic field). This prototype tool, named BAPER and developed with a commercial neural network toolbox, could be used to support short and medium term mission planning in order to improve and maximise the batteries lifetime, determining which are the future best charge/discharge cycles for the batteries given their present states, in view of a Cluster II mission extension. This study focuses on the five Silver-Cadmium batteries onboard of Tango, the fourth Cluster II satellite, but time restrains have allowed so far to perform an assessment only on the first battery. In their most basic form, ANNs are hyper-dimensional curve fits for non-linear data. With their remarkable ability to derive meaning from complicated or imprecise history data, ANN can be used to extract patterns and detect trends that are too complex to be noticed by either humans or other computer techniques. ANNs learn by example, and this is why they can be described as an inductive, or data-based models for the simulation of input/target mappings. A trained ANN can be thought of as an "expert" in the category of information it has been given to analyse, and this expert can then be used, as in this project, to provide projections given new situations of interest and answer "what if" questions. The most appropriate algorithm, in terms of training speed and memory storage requirements, is clearly the Levenberg

  9. Performance assessment of air quality monitoring networks using principal component analysis and cluster analysis

    International Nuclear Information System (INIS)

    Lu, Wei-Zhen; He, Hong-Di; Dong, Li-yun

    2011-01-01

    This study aims to evaluate the performance of two statistical methods, principal component analysis and cluster analysis, for the management of air quality monitoring network of Hong Kong and the reduction of associated expenses. The specific objectives include: (i) to identify city areas with similar air pollution behavior; and (ii) to locate emission sources. The statistical methods were applied to the mass concentrations of sulphur dioxide (SO 2 ), respirable suspended particulates (RSP) and nitrogen dioxide (NO 2 ), collected in monitoring network of Hong Kong from January 2001 to December 2007. The results demonstrate that, for each pollutant, the monitoring stations are grouped into different classes based on their air pollution behaviors. The monitoring stations located in nearby area are characterized by the same specific air pollution characteristics and suggested with an effective management of air quality monitoring system. The redundant equipments should be transferred to other monitoring stations for allowing further enlargement of the monitored area. Additionally, the existence of different air pollution behaviors in the monitoring network is explained by the variability of wind directions across the region. The results imply that the air quality problem in Hong Kong is not only a local problem mainly from street-level pollutions, but also a region problem from the Pearl River Delta region. (author)

  10. Aerodynamic characteristics and heat radiation performance of sportswear fabrics

    Science.gov (United States)

    Koga, H.; Hiratsuka, M.; Ito, S.; Konno, A.

    2017-10-01

    Sports such as swimming, speed skating, and marathon are sports competing for time. In recent years, reduction of the fluid drag of sportswear is required for these competitions in order to improve the record. In addition, sweating and discomfort due to body temperature rise during competition are thought to affect competitor performance, and heat radiation performance is also an important factor for sportswear. The authors have measured fluid force drag by wrapping cloth around a cylinder and have confirmed their differences due to the roughness of the fabric surface, differences in sewing. The authors could be verified the drag can be reduced by the position of the wear stitch. This time, we measured the heat radiation performance of 14 types of cloths whose aero dynamic properties are known using cylinders which are regarded as human fuselages, and found elements of cloth with heat radiation performance. It was found to be important for raising the heat radiation performance of sportswear that the fabric is thin and flat surface processing.

  11. Improving Network Performance with Affinity based Mobility Model in Opportunistic Network

    OpenAIRE

    Suvadip Batabyal; Parama Bhaumik

    2012-01-01

    Opportunistic network is a type of Delay Tolerant Network which is characterized by intermittent connectivity amongst the nodes and communication largely depends upon the mobility of the participating nodes. The network being highly dynamic, traditional MANET protocols cannot be applied and the nodes must adhere to store-carry-forward mechanism. Nodes do not have the information about the network topology, number of participating nodes and the location of the destination node. Hence, message ...

  12. Performance of Flow-Aware Networking in LTE backbone

    DEFF Research Database (Denmark)

    Sniady, Aleksander; Soler, José

    2012-01-01

    technologies, such as Long Term Evolution (LTE). This paper proposes usage of a modified Flow Aware Networking (FAN) technique for enhancing Quality of Service (QoS) in the all-IP transport networks underlying LTE backbone. The results obtained with OPNET Modeler show that FAN, in spite of being relatively...

  13. assessment of neural networks performance in modeling rainfall ...

    African Journals Online (AJOL)

    Sholagberu

    neural network architecture for precipitation prediction of Myanmar, World Academy of. Science, Engineering and Technology, 48, pp. 130 – 134. Kumarasiri, A.D. and Sonnadara, D.U.J. (2006). Rainfall forecasting: an artificial neural network approach, Proceedings of the Technical Sessions,. 22, pp. 1-13 Institute of Physics ...

  14. Cell outage compensation in LTE networks: Algorithms and performance assessment

    NARCIS (Netherlands)

    Amirijoo, M.; Jorguseski, L.; Litjens, R.; Schmelz, L.C.

    2011-01-01

    Cell outage compensation is a self-healing function and as such part of the Self-Organising Networks concept for mobile wireless networks. It aims at mitigating the degradation of coverage, capacity and service quality caused by a cell or site level outage. Upon detection of such an outage, cell

  15. Network embeddedness and organizational performance. The strength of strong ties in Dutch higher education

    NARCIS (Netherlands)

    Schalk, J.; Torenvlied, R.; Allen, J.P.

    2010-01-01

    With only few exceptions, current research in public management on the effects of inter-organizational networks on organizational performance focuses either on network activity or on the inter-organizational network structure. The present paper theoretically links both approaches and tests two

  16. From Network to Research – Ten Years of Music Informatics, Performance and Aesthetics

    DEFF Research Database (Denmark)

    Frimodt-Møller, Søren; Grund, Cynthia M.; Jensen, Kristoffer

    2011-01-01

    This article briefly chronicles the history of the Nordic Network of Music Informatics, Performance and Aesthetics (NNIMIPA) and its roots in previous research networks and milieus. It explains how a cross-disciplinary network works and gives rise to research projects that bridge the gap between...

  17. The Impact of Increases in Subsidiary Autonomy and Network Relationships on Performance

    DEFF Research Database (Denmark)

    Gammelgaard, Jens; McDonald, Frank; Stephan, Andreas

    2012-01-01

    This paper uses network approaches to subsidiary theory to investigate the performance impacts of interactions among the factors of autonomy, intra-organizational network relationships, and inter-organizational network relationships. The paper offers an analysis of both direct and indirect intera...

  18. OPTIMAL CONFIGURATION OF A COMMAND AND CONTROL NETWORK: BALANCING PERFORMANCE AND RECONFIGURATION CONSTRAINTS

    Energy Technology Data Exchange (ETDEWEB)

    L. DOWELL

    1999-07-01

    The optimization of the configuration of communications and control networks is important for assuring the reliability and performance of the networks. This paper presents techniques for determining the optimal configuration for such a network in the presence of communication and connectivity constraints.

  19. Adaptive sampling rate control for networked systems based on statistical characteristics of packet disordering.

    Science.gov (United States)

    Li, Jin-Na; Er, Meng-Joo; Tan, Yen-Kheng; Yu, Hai-Bin; Zeng, Peng

    2015-09-01

    This paper investigates an adaptive sampling rate control scheme for networked control systems (NCSs) subject to packet disordering. The main objectives of the proposed scheme are (a) to avoid heavy packet disordering existing in communication networks and (b) to stabilize NCSs with packet disordering, transmission delay and packet loss. First, a novel sampling rate control algorithm based on statistical characteristics of disordering entropy is proposed; secondly, an augmented closed-loop NCS that consists of a plant, a sampler and a state-feedback controller is transformed into an uncertain and stochastic system, which facilitates the controller design. Then, a sufficient condition for stochastic stability in terms of Linear Matrix Inequalities (LMIs) is given. Moreover, an adaptive tracking controller is designed such that the sampling period tracks a desired sampling period, which represents a significant contribution. Finally, experimental results are given to illustrate the effectiveness and advantages of the proposed scheme. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

  20. Optimization of observation plan based on the stochastic characteristics of the geodetic network

    Directory of Open Access Journals (Sweden)

    Pachelski Wojciech

    2016-06-01

    Full Text Available Optimal design of geodetic network is a basic subject of many engineering projects. An observation plan is a concluding part of the process. Any particular observation within the network has through adjustment a different contribution and impact on values and accuracy characteristics of unknowns. The problem of optimal design can be solved by means of computer simulation. This paper presents a new method of simulation based on sequential estimation of individual observations in a step-by-step manner, by means of the so-called filtering equations. The algorithm aims at satisfying different criteria of accuracy according to various interpretations of the covariance matrix. Apart of them, the optimization criterion is also amount of effort, defined as the minimum number of observations required.

  1. Vibrational characteristics of graphene sheets elucidated using an elastic network model.

    Science.gov (United States)

    Kim, Min Hyeok; Kim, Daejoong; Choi, Jae Boong; Kim, Moon Ki

    2014-08-07

    Recent studies of graphene have demonstrated its great potential for highly sensitive resonators. In order to capture the intrinsic vibrational characteristics of graphene, we propose an atomistic modeling method called the elastic network model (ENM), in which a graphene sheet is modeled as a mass-spring network of adjacent atoms connected by various linear springs with specific bond ratios. Normal mode analysis (NMA) reveals the various vibrational features of bi-layer graphene sheets (BLGSs) clamped at two edges. We also propose a coarse-graining (CG) method to extend our graphene study into the meso- and macroscales, at which experimental measurements and synthesis of graphene become practical. The simulation results show good agreement with experimental observations. Therefore, the proposed ENM approach will not only shed light on the theoretical study of graphene mechanics, but also play an important role in the design of highly-sensitive graphene-based resonators.

  2. Predicting Performance Under Acute Stress : The Role of Individual Characteristics

    NARCIS (Netherlands)

    Delahaij, R.; Dam, K. van; Gaillard, A.W.K.; Soeters, J.

    2011-01-01

    This prospective study examined how differences in coping style, coping self-efficacy, and metacognitive awareness influence coping behavior and performance during a realistic acute stressful exercise in 2 military samples (n = 122 and n = 132). Results showed that coping self-efficacy and coping

  3. Performance characteristics and blood profile of West African dwarf ...

    African Journals Online (AJOL)

    A twelve week trial was investigated to evaluate performance and blood profile of West African dwarf (WAD) goats fed malted sorghum sprout with pineapple waste (MSPW) based diet. The malted sorghum sprout and pineapple waste was at ratio 1:2 (weight/weight) respectively. Sixteen WAD goats with average initial ...

  4. Job characteristics, flow, and performance : the moderating role of conscientiousness

    NARCIS (Netherlands)

    Demerouti, E.

    2006-01-01

    The present article aims to show the importance of positive work-related experiences within occupational health psychology by examining the relationship between flow at work (i.e., absorption, work enjoyment, and intrinsic work motivation) and job performance. On the basis of the literature, it was

  5. Performance gaps in energy consumption : household groups and building characteristics

    NARCIS (Netherlands)

    van den Brom, P.I.; Meijer, A.; Visscher, H.J.

    2017-01-01

    The difference between actual and calculated energy is called the ‘energy-performance gap’. Possible explanations for this gap are construction mistakes, improper adjusting of equipment, excessive simplification in simulation models and occupant behaviour. Many researchers and governmental

  6. Performance and carcass characteristics of Japanese quail as ...

    African Journals Online (AJOL)

    The effect of sex and the supplementation of the prebiotic, mannan oligosaccharides (MOS), the acidifier, calcium propionate (CPr) or their combination in the feed of Japanese quail (Coturnix japonica) on their performance and carcass quality was examined in this experimentation. Three hundred, 1-day old Japanese quail ...

  7. Southern hemisphere coal characteristics and their impact on plant performance

    Energy Technology Data Exchange (ETDEWEB)

    Chiou, Y Y; Dickson, A J; Lowe, A; Pearson, J M; Pitman, B L; Semark, P M [Taiwan Power Company (Taiwan)

    1992-09-01

    The paper reports performance information of specific utilities fired by coal mined in the Southern Hemisphere. It includes information from Pacific Power Services, Australia, the China Light and Power Company, Hong Kong, the Taiwan Power Company, Taiwan, and the South Africa Electricity Power Company, South Africa. 12 refs., 3 figs., 12 tabs.

  8. Sibsize, Family Environment, Cognitive Performance, and Affective Characteristics

    Science.gov (United States)

    Marjoribanks, Kevin

    1976-01-01

    Incorporates measures of family environment (parent-child interaction) into research methodology to study the effects of sibsize (family size and birth order) on a child's cognitive performance and affective behavior. Provides tentative support for the confluence model of sibsize influences on children's behaviors. (RL)

  9. PGF2α induced estrus characteristics and reproductive performance ...

    African Journals Online (AJOL)

    Structured questionnaire and a field survey were applied on a total of 200 randomly selected households. ... Records of animal identification, parameters of reproductive performance such as weaning age and age at puberty, litter size, kidding interval (KI), the type of management practice and clinical parameters were taken ...

  10. Individual, contextual and network characteristics of blood donors and non-donors: a systematic review of recent literature

    NARCIS (Netherlands)

    Piersma, Tjeerd W.; Bekkers, René; Klinkenberg, Elisabeth F.; de Kort, Wim L. A. M.; Merz, Eva-Maria

    2017-01-01

    Background. The ageing population and recent migration flows may negatively affect the blood supply in the long term, increasing the importance of targeted recruitment and retention strategies to address donors. This review sought to identify individual, network and contextual characteristics

  11. 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

  12. PWR and WWER fuel performance. A comparison of major characteristics

    International Nuclear Information System (INIS)

    Weidinger, H.

    2006-01-01

    PWR and WWER fuel technologies have the same basic performance targets: most effective use of the energy stored in the fuel and highest possible reliability. Both fuel technologies use basically the same strategies to reach these targets: 1) Optimized reload strategies; 2) Maximal use of structural material with low neutron cross sections; 3) Decrease the fuel failure frequency towards a 'zero failure' performance by understanding and eliminating the root causes of those defects. The key driving force of the technology of both, PWR and WWER fuel is high burn-up. Presently a range of 45 - 50 MWD/kgU have been reached commercially for PWR and WWER fuel. The main technical limitations to reach high burn-up are typically different for PWR and WWER fuel: for PWR fuel it is the corrosion and hydrogen uptake of the Zr-based materials; for WWER fuel it is the mechanical and dimensional stability of the FA (and the whole core). Corrosion and hydrogen uptake of Zr-materials is a 'non-problem' for WWER fuel. Other performance criteria that are important for high burn-up are the creep and growth behaviour of the Zr materials and the fission gas release in the fuel rod. There exists a good and broad data base to model and design both fuel types. FA and fuel rod vibration appears to be a generic problem for both fuel types but with more evidence for PWR fuel performance reliability. Grid-to-rod fretting is still a major issue in the fuel failure statistics of PWR fuel. Fuel rod cladding defects by debris fretting is no longer a key problem for PWR fuel, while it still appears to be a significant root cause for WWER fuel failures. 'Zero defect' fuel performance is achievable with a high probability, as statistics for US PWR and WWER-1000 fuel has shown

  13. Performance in wireless networks and industrial wireless networks on control processes in real time under industrial environments

    Directory of Open Access Journals (Sweden)

    Juan F. Monsalve-Posada

    2015-01-01

    Full Text Available The growing use of Ethernet networks on the industrial automation pyramid has led many companies to develop new devices to operate in requirements of this level, nowadays it is called Industrial Ethernet network, on the market there are various sensors and actuators to industrial scale equipped with this technology, many of these devices are very expensive. In this paper, the performance of two wireless networks is evaluated, the first network has conventional Ethernet devices, and the second network has Industrial Ethernet devices. For the process we vary four parameters such as distance, number of bytes, the signal to noise ratio, and the packet error rate, and then we measure delays and compare with metric statistics results, Box Plot graphs were used for the analysis. Finally, we conclude that under the parameters and conditions tested, wireless networks can serve as a communication system in control applications with allowable delays of up to 50 ms, in addition, the results show a better performance of Industrial Ethernet networks over conventional networks, with differences in the RTT of milliseconds. Therefore, it is recommended to establish what risk is for the process to control these delays to determine if the equipment conventional applies, since under certain features like humidity and temperature can operate properly for a considerable time and at lower cost than devices to Industrial Ethernet.

  14. Suns-VOC characteristics of high performance kesterite solar cells

    Science.gov (United States)

    Gunawan, Oki; Gokmen, Tayfun; Mitzi, David B.

    2014-08-01

    Low open circuit voltage (VOC) has been recognized as the number one problem in the current generation of Cu2ZnSn(Se,S)4 (CZTSSe) solar cells. We report high light intensity and low temperature Suns-VOC measurement in high performance CZTSSe devices. The Suns-VOC curves exhibit bending at high light intensity, which points to several prospective VOC limiting mechanisms that could impact the VOC, even at 1 sun for lower performing samples. These VOC limiting mechanisms include low bulk conductivity (because of low hole density or low mobility), bulk or interface defects, including tail states, and a non-ohmic back contact for low carrier density CZTSSe. The non-ohmic back contact problem can be detected by Suns-VOC measurements with different monochromatic illuminations. These limiting factors may also contribute to an artificially lower JSC-VOC diode ideality factor.

  15. Performance characteristics of aerodynamically optimum turbines for wind energy generators

    Science.gov (United States)

    Rohrbach, C.; Worobel, R.

    1975-01-01

    This paper presents a brief discussion of the aerodynamic methodology for wind energy generator turbines, an approach to the design of aerodynamically optimum wind turbines covering a broad range of design parameters, some insight on the effect on performance of nonoptimum blade shapes which may represent lower fabrication costs, the annual wind turbine energy for a family of optimum wind turbines, and areas of needed research. On the basis of the investigation, it is concluded that optimum wind turbines show high performance over a wide range of design velocity ratios; that structural requirements impose constraints on blade geometry; that variable pitch wind turbines provide excellent power regulation and that annual energy output is insensitive to design rpm and solidity of optimum wind turbines.

  16. Electrical performance characteristics of the SSC Accelerator System String Test

    International Nuclear Information System (INIS)

    Robinson, W.; Burgett, W.; Dombeck, T.; Gannon, J.; Kraushaar, P.; McInturff, A.; Savord, T.; Tool, G.

    1993-05-01

    The string test facility was constructed to provide a development test bed for the arc regions of the Superconducting Super Collider (SSC). Significant effort has been devoted to the development and testing of superconducting magnets, spools, and accelerator control systems required for the SSC. The string test facility provides the necessary environment required to evaluate the operational performance of these components as they are configured as an accelerator lens in the collider. This discussion will review the results of high current testing of the string conducted to evaluate magnet element uniformity and compatibility, the splice resistance used to connect the magnets, and system response to various quench conditions. Performance results of the spools, energy bypass systems, energy dump, and the power supply system are also discussed

  17. Electrical performance characteristics of the SSC Accelerator System String Test

    International Nuclear Information System (INIS)

    Robinson, W.; Burgett, W.; Dombeck, T.; Gannon, J.; Kraushaar, P.; McInturff, A.; Savord, T.; Tool, G.

    1993-01-01

    The string test facility was constructed to provide a development test bed for the arc regions of the Superconducting Super Collider (SSC). Significant effort has been devoted to the development and testing of superconducting magnets, spools, and accelerator control systems required for the SSC. The string test facility provides the necessary environment required to evaluate the operational performance of these components as they are configured as an accelerator lens in the collider. This discussion will review the results of high current testing of the string conducted to evaluate magnet element uniformity and compatibility, the splice resistance used to connect the magnets, and system response to various quench conditions. Performance results of the spools, energy bypass systems, energy dump, and the power supply system are also discussed

  18. The HARP resistive plate chambers: Characteristics and physics performance

    International Nuclear Information System (INIS)

    Ammosov, V.; Boyko, I.; Chelkov, G.; Dedovitch, D.; Dumps, R.; Dydak, F.; Elagin, A.; Gapienko, V.; Gostkin, M.; Guskov, A.; Kroumchtein, Z.; Koreshev, V.; Linssen, L.; Nefedov, Yu.; Nikolaev, K.; Semak, A.; Sviridov, Yu.; Usenko, E.; Wotschack, J.; Zaets, V.; Zhemchugov, A.

    2007-01-01

    The HARP Resistive Plate Chamber (RPC) system was designed for time-of-flight measurement in the large-angle acceptance region of the HARP spectrometer. It comprised 46 four-gap glass RPCs covering an area of ∼8m 2 . The design of the RPCs, their operation, intrinsic properties, and system performance are described. The intrinsic time resolution of the RPCs is better than 130ps leading to a system time resolution of ∼175ps

  19. The performance characteristics of groundnut ( Arachis hypogea , L ...

    African Journals Online (AJOL)

    The ethyl-esters were blended with automotive gas oil at (0 to 20%) mix with 5% increment of groundnut ethyl-esters to produce biodiesel. The performance of a 2.46 kW diesel engine was evaluated using the groundnut biodiesel at five loading conditions (0, 25, 50, 75 and 100% of full load). Automotive gas oil was used as ...

  20. The characteristics and performance of international joint ventures in Thailand

    OpenAIRE

    Suwannarat, P

    2010-01-01

    The importance of strategic alliances in the form of international joint ventures (IJVs) is growing in the present international business environment where competition is on a global scale. A review of the IJV literature, especially in developing countries, shows an over-emphasis on China and the NIEs (the first tier newly-industrialising economies: Taiwan, Singapore, Hong Kong, and South Korea). To date, relatively little attention has been paid to the ASEAN4 countries (the high-performing e...

  1. Adaptation and learning: characteristic time scales of performance dynamics.

    Science.gov (United States)

    Newell, Karl M; Mayer-Kress, Gottfried; Hong, S Lee; Liu, Yeou-Teh

    2009-12-01

    A multiple time scales landscape model is presented that reveals structures of performance dynamics that were not resolved in the traditional power law analysis of motor learning. It shows the co-existence of separate processes during and between practice sessions that evolve in two independent dimensions characterized by time scales that differ by about an order of magnitude. Performance along the slow persistent dimension of learning improves often as much and sometimes more during rest (memory consolidation and/or insight generation processes) than during a practice session itself. In contrast, the process characterized by the fast, transient dimension of adaptation reverses direction between practice sessions, thereby significantly degrading performance at the beginning of the next practice session (warm-up decrement). The theoretical model fits qualitatively and quantitatively the data from Snoddy's [Snoddy, G. S. (1926). Learning and stability. Journal of Applied Psychology, 10, 1-36] classic learning study of mirror tracing and other averaged and individual data sets, and provides a new account of the processes of change in adaptation and learning. 2009 Elsevier B.V. All rights reserved.

  2. Energetic Performance of Service-oriented Multi-radio Networks: Issues and Perspectives

    OpenAIRE

    Caporuscio , Mauro; Charlet , Damien; Issarny , Valérie; Navarra , Alfredo

    2006-01-01

    Wireless devices now hold multiple radio interfaces, allowing to switch from one network to another according to required connectivity and related quality. Still, the selection of the best radio interface for a specific connection is under the responsibility of the end-user in most cases. Integrated multi-radio network management so as to improve the overall performance of the network(s) has led to a number of research efforts over the last few years. However, several challenges remain due to...

  3. Structure-function relationships in elderly resting-state-networks : influence of age and cognitive performance

    OpenAIRE

    Jockwitz, Christiane

    2016-01-01

    The aim of this work was to investigate the structure-function relationship in cognitive resting state networks in a large population-based elderly sample. The first study characterized the functional connectivity in four cognitive resting state networks with respect to age, gender and cognitive performance: Default Mode Network (DMN), executive, and left and right frontoparietal resting state networks. The second study assessed the structural correlates of the functional reorganization of th...

  4. PERFORMANCE COMPARISON FOR INTRUSION DETECTION SYSTEM USING NEURAL NETWORK WITH KDD DATASET

    Directory of Open Access Journals (Sweden)

    S. Devaraju

    2014-04-01

    Full Text Available Intrusion Detection Systems are challenging task for finding the user as normal user or attack user in any organizational information systems or IT Industry. The Intrusion Detection System is an effective method to deal with the kinds of problem in networks. Different classifiers are used to detect the different kinds of attacks in networks. In this paper, the performance of intrusion detection is compared with various neural network classifiers. In the proposed research the four types of classifiers used are Feed Forward Neural Network (FFNN, Generalized Regression Neural Network (GRNN, Probabilistic Neural Network (PNN and Radial Basis Neural Network (RBNN. The performance of the full featured KDD Cup 1999 dataset is compared with that of the reduced featured KDD Cup 1999 dataset. The MATLAB software is used to train and test the dataset and the efficiency and False Alarm Rate is measured. It is proved that the reduced dataset is performing better than the full featured dataset.

  5. myCourse: An Educational Content Management Platform with Social Networking Characteristics

    Directory of Open Access Journals (Sweden)

    Ioannis Ignatiadis

    2010-12-01

    Full Text Available We adopt the direction towards new educational and pedagogic paradigms, where learning is a process of emergence and co-evolution of the individual, the social group and the wider society. In this direction, Service-Oriented Architectures are becoming a popular system paradigm for e-learning. In this article, we present our research and development efforts to provide a social networking learning platform for developing services which address the personal learning needs of the users and enable them to create value. We also present the specific characteristics of our community driven service framework and discuss our approach in comparison to other similar approaches and frameworks.

  6. Monofractal Characteristics of Traffic in Wireless Sensor Networks for Smart Grid

    Directory of Open Access Journals (Sweden)

    Ming-Yue Zhai

    2014-05-01

    Full Text Available Wireless sensor networks (WSNs have extensive applications in the smart grid in recently years. The time series in WSNs in smart grid should be discussed by analysis method which is non-linear. The method of monofractal is used here. Self-similar Hurst parameter calculated by the algorithm of Rescaled Range Analysis (R/S and fractal dimension are obtained, which confirm that the time sequences in WSNs for smart grid belong to the fractal sets and have the characteristic of self- similarity.

  7. Characteristics of sprint performance in college football players.

    Science.gov (United States)

    Brechue, William F; Mayhew, Jerry L; Piper, Fontaine C

    2010-05-01

    To investigate sprinting strategy, acceleration and velocity patterns were determined in college football players (n = 61) during performance of a 9.1-, 36.6-, and 54.9-m sprints. Acceleration and velocity were determined at 9.1-m intervals during each sprint. Lower-body strength and power were evaluated by 1 repetition maximum (1-RM) squat, power clean, jerk, vertical jump, standing long jump, and standing triple jump. Sprint times averaged 1.78 +/- 0.11 seconds (9.1 m), 5.18 +/- 0.35 seconds (36.6 m), and 7.40 +/- 0.53 seconds. Acceleration peaked at 9.1 m (2.96 +/- 0.44 m x s(-2)), was held constant at 18.3 m (3.55 +/- 0.0.94 m x s(-2)), and was negative at 27.4 m (-1.02 +/- 0.72 m x s(-2)). Velocity peaked at 18.3 m (8.38 +/- 0.65 m x s(-2)) and decreased slightly, but significantly at 27.4 m (7.55 +/- 0.66 m x s(-2)), associated with the negative acceleration. Measures of lower-body strength were significantly related to acceleration, velocity, and sprint performance only when corrected for body mass. Lower-body strength/BM and power correlated highest with 36.6-m time (rs = -0.55 to -0.80) and with acceleration (strength r = 0.67-0.49; power r = 0.73-0.81) and velocity (strength r = 0.68-0.53; power r = 0.74-0.82) at 9.1 m. Sprint times and strength per body mass were significantly lower in lineman compared with linebackers-tight ends and backs. The acceleration and velocity patterns were the same for each position group, and differences in sprint time were determined by the magnitude of acceleration and velocity at 9.1 and 18.3 m. Sprint performance in football players is determined by a rapid increase in acceleration (through 18.3 m) and a high velocity maintained throughout the sprint and is independent of position played. The best sprint performances (independent of sprint distance) appear to be related to the highest initial acceleration (through 18.3 m) and highest attained and maintained velocity. Strength relative to body mass and power appears to

  8. A visual analytics system for optimizing the performance of large-scale networks in supercomputing systems

    Directory of Open Access Journals (Sweden)

    Takanori Fujiwara

    2018-03-01

    Full Text Available The overall efficiency of an extreme-scale supercomputer largely relies on the performance of its network interconnects. Several of the state of the art supercomputers use networks based on the increasingly popular Dragonfly topology. It is crucial to study the behavior and performance of different parallel applications running on Dragonfly networks in order to make optimal system configurations and design choices, such as job scheduling and routing strategies. However, in order to study these temporal network behavior, we would need a tool to analyze and correlate numerous sets of multivariate time-series data collected from the Dragonfly’s multi-level hierarchies. This paper presents such a tool–a visual analytics system–that uses the Dragonfly network to investigate the temporal behavior and optimize the communication performance of a supercomputer. We coupled interactive visualization with time-series analysis methods to help reveal hidden patterns in the network behavior with respect to different parallel applications and system configurations. Our system also provides multiple coordinated views for connecting behaviors observed at different levels of the network hierarchies, which effectively helps visual analysis tasks. We demonstrate the effectiveness of the system with a set of case studies. Our system and findings can not only help improve the communication performance of supercomputing applications, but also the network performance of next-generation supercomputers. Keywords: Supercomputing, Parallel communication network, Dragonfly networks, Time-series data, Performance analysis, Visual analytics

  9. Characteristics and lessons learned from practice-based research networks (PBRNs in the United States

    Directory of Open Access Journals (Sweden)

    Keller S

    2012-09-01

    Full Text Available Melinda M Davis,1,2 Sara Keller,1 Jennifer E DeVoe,1,3 Deborah J Cohen11Department of Family Medicine, 2Oregon Rural Practice-based Research Network, Oregon Health & Science University, Portland, OR, USA; 3OCHIN Practice-based Research Network, Portland, OR, USAAbstract: Practice-based research networks (PBRNs are organizations that involve practicing clinicians in asking and answering clinically relevant research questions. This review explores the origins, characteristics, funding, and lessons learned through practice-based research in the United States. Primary care PBRNs emerged in the USA in the 1970s. Early studies explored the etiology of common problems encountered in primary care practices (eg, headache, miscarriage, demonstrating the gap between research conducted in controlled specialty settings and real-world practices. Over time, national initiatives and an evolving funding climate have shaped PBRN development, contributing to larger networks, a push for shared electronic health records, and the use of a broad range of research methodologies (eg, observational studies, pragmatic randomized controlled trials, continuous quality improvement, participatory methods. Today, there are over 160 active networks registered with the Agency for Healthcare Research and Quality's PBRN Resource Center that engage primary care clinicians, pharmacists, dentists, and other health care professionals in research and quality-improvement initiatives. PBRNs provide an important laboratory for encouraging collaborative research partnerships between academicians and practices or communities to improve population health, conduct comparative effectiveness and patient-centered outcomes research, and study health policy reform. PBRNs continue to face critical challenges that include: (1 adapting to a changing landscape; (2 recruiting and retaining membership; (3 securing infrastructure support; (4 straddling two worlds (academia and community and managing

  10. Performance characteristics of the ARCHITECT anti-HCV assay.

    Science.gov (United States)

    Jonas, Gesa; Pelzer, Claudia; Beckert, Christian; Hausmann, Michael; Kapprell, Hans-Peter

    2005-10-01

    The ARCHITECT Anti-HCV assay is a fully automated high throughput chemiluminescent microparticle immunoassay (CMIA) for the detection of antibodies to structural and nonstructural proteins of the hepatitis C virus (HCV). To further enhance the performance of this test, the assay was modified to improve the specificity for blood donor specimens. The specificity of the enhanced ARCHITECT Anti-HCV assay was evaluated by screening blood donor samples randomly collected from various German blood banks, as well as hospitalized patient samples derived from Germany and the US. Additionally, antibody sensitivity was determined on commercially available anti-HCV seroconversion panels and on a commercially available worldwide anti-HCV genotype performance panel. Apparent specificity of the modified ARCHITECT Anti-HCV assay in a blood donor population consisting of 3811 specimens was 99.92%, compared to 99.76% for the current on-market assay. Additionally, antibody sensitivity was determined on commercially available anti-HCV seroconversion panels. Seroconversion sensitivity equivalent to or better than the current on-market product was observed by testing 33 seroconversion panels. This study demonstrates that the modified version of the ARCHITECT Anti-HCV assay shows improved specificity for blood donor specimens compared to the current assay on market without compromising sensitivity. With the availability of the improved ARCHITECT Anti-HCV assay and the recent launch of the ARCHITECT HIV Ag/Ab Combo assay, the ARCHITECT system now offers a full hepatitis/retrovirus menu with excellent performance on a high throughput, random access, automated analyzer, ideally suited for blood screening and diagnostic applications.

  11. Performance characteristics of solar-photovoltaic flywheel-storage systems

    Science.gov (United States)

    Jarvinen, P. O.; Brench, B. L.; Rasmussen, N. E.

    A solar photovoltaic energy flywheel storage and conversion system for residential applications was tested. Performance and efficiency measurements were conducted on the system, which utilizes low loss magnetic bearings, maximum power point tracking of the photovoltaic array, integrated permanent magnet motor generator, and output power conditioning sections of either the stand alone cycloconverter or utility interactive inverter type. The overall in/out electrical storage efficiency of the flywheel system was measured along with the power transfer efficiencies of the individual components and the system spin down tare losses. The system compares favorably with systems which use batteries and inverters.

  12. Performance characteristics of a horizontal axis turbine with fusion winglet

    International Nuclear Information System (INIS)

    Zhu, Bing; Sun, Xiaojing; Wang, Ying; Huang, Diangui

    2017-01-01

    Any technique or method that can improve the efficiency in exploiting renewable wind or marine current energy has got a great significance today. It has been reported that adding a winglet at the tip of the rotor blades on a horizontal axis wind turbine can increase its power performance. The purpose of this paper is to adopt a numerical method to investigate the effects of different winglet configurations on turbine performance, especially focusing on the direction for the winglet tip to point towards (the suction side, pressure side or both sides of the main blade). The results show that the new design of an integrated fusion winglet proposed in this paper can generally improve the main blade's power producing ability, which is further enhanced with the increase of turbine's tip speed ratio with a maximum power augmentation of about 3.96%. No matter which direction the winglet tip faces, the installation angle of the winglet should match well with the real angle of incoming flow. As a whole, the turbine with winglet of two tips facing to both sides of the main blade can produce much more power than the one of winglet configuration whose tip faces only one side for different blade hub pitch angles and vast majority of tip speed ratios. The working principle behind the winglet in improving turbine performance may be that it can block the downwash fluid easily flowing around the tip section of the main blade from the pressure side to suction side, and hence diffuse and spread out the tip vortex. As a result, it finally decreases the energy loss. Besides, the relative projected rotor area in incoming flow direction will also be reduced due to the addition of the winglet, which is also helpful to turbine's power coefficient. - Highlights: • Added winglet generally increase the turbine energy extraction performance. • Winglet facing blade both sides is usually superior to that of facing one side. • Winglet can isolate downwash fluid easily flowing

  13. Performance Evaluation of a Routing Protocol in Wireless Sensor Network

    National Research Council Canada - National Science Library

    Cheng Kiat Amos, Teo

    2005-01-01

    ... and have topologies engineered. As such, recent research into wireless sensor networks has attracted great interest due to its diversity of applications, ranging in areas such as home, health, environmental and military applications...

  14. The Impact of Network Performance on Warfighter Effectiveness

    National Research Council Canada - National Science Library

    Porche, III, Isaac R; Wilson, Bradley

    2006-01-01

    ... to warfighter effectiveness at the tactical level. It will give the Army unique and relevant information to guide its transition to a new force makeup that will be knowledge-based and network-centric...

  15. Comparative performance of some popular artificial neural network ...

    Indian Academy of Sciences (India)

    tificial neural network domain (viz., local search algorithms, global search ... branches of astronomy for automated data analysis and other applications like ...... such as standard backpropagation, fuzzy logic, genetic algorithms, fractals etc.,.

  16. Linux containers networking: performance and scalability of kernel modules

    NARCIS (Netherlands)

    Claassen, J.; Koning, R.; Grosso, P.; Oktug Badonnel, S.; Ulema, M.; Cavdar, C.; Zambenedetti Granville, L.; dos Santos, C.R.P.

    2016-01-01

    Linux container virtualisation is gaining momentum as lightweight technology to support cloud and distributed computing. Applications relying on container architectures might at times rely on inter-container communication, and container networking solutions are emerging to address this need.

  17. Influence of current pulse shape on directly modulated system performance in metro area optical networks

    Science.gov (United States)

    Campos, Carmina del Rio; Horche, Paloma R.; Martin-Minguez, Alfredo

    2011-03-01

    Due to the fact that a metro network market is very cost sensitive, direct modulated schemes appear attractive. In this paper a CWDM (Coarse Wavelength Division Multiplexing) system is studied in detail by means of an Optical Communication System Design Software; a detailed study of the modulated current shape (exponential, sine and gaussian) for 2.5 Gb/s CWDM Metropolitan Area Networks is performed to evaluate its tolerance to linear impairments such as signal-to-noise-ratio degradation and dispersion. Point-to-point links are investigated and optimum design parameters are obtained. Through extensive sets of simulation results, it is shown that some of these shape pulses are more tolerant to dispersion when compared with conventional gaussian shape pulses. In order to achieve a low Bit Error Rate (BER), different types of optical transmitters are considered including strongly adiabatic and transient chirp dominated Directly Modulated Lasers (DMLs). We have used fibers with different dispersion characteristics, showing that the system performance depends, strongly, on the chosen DML-fiber couple.

  18. Performance characteristics of ZLC 37 Siemens gamma camera

    International Nuclear Information System (INIS)

    Abdelgadir, Wafaa Abdelrahman

    1994-04-01

    The relationships between the ZLC 37 Siemens γ camera parameters (energy resolution, plane sensitivity, intrinsic uniformity, intrinsic resolution, system uniformity and system resolution) and diagnostic imaging performance was investigated. These parameters when computers when compared with internationally published data showed that the ZLC 37 Siemens γ cameras is in good operative conditions. The effect of the scattering media and WW on the spatial resolution, when the distance is kept fixed were investigated. Comparison of resolution for the media (air, water, water + radioactivity when using WW (10, 15,20%) showed that the resolution is best for air, better for water and worse for water + radioactivity up to a concentration of 8% for a 10% WW. (Author)

  19. Performance characteristics of ZLC 37 Siemens gamma camera

    Energy Technology Data Exchange (ETDEWEB)

    Abdelgadir, Wafaa Abdelrahman [Department of Physics, Faculty of Science, University of Khartoum, Khartoum (Sudan)

    1994-04-01

    The relationships between the ZLC 37 Siemens {gamma} camera parameters (energy resolution, plane sensitivity, intrinsic uniformity, intrinsic resolution, system uniformity and system resolution) and diagnostic imaging performance was investigated. These parameters when computers when compared with internationally published data showed that the ZLC 37 Siemens {gamma} cameras is in good operative conditions. The effect of the scattering media and WW on the spatial resolution, when the distance is kept fixed were investigated. Comparison of resolution for the media (air, water, water + radioactivity) when using WW (10, 15,20%) showed that the resolution is best for air, better for water and worse for water + radioactivity up to a concentration of 8% for a 10% WW. (Author) 28 refs. , 10 tabs. , 22 figs. Also available from the Department of Physics, Faculty of Science, University of Khartoum, Khartoum (SD)

  20. Electrical performance characteristics of the SSC Accelerator System String Test

    International Nuclear Information System (INIS)

    Robinson, W.; Burgett, W.; Gannon, J.; Kraushaar, P.; Mcinturff, A.; Nehring, R.; Saladin, V.; Savord, T.; Sorrensen, G.; Smellie, R.; Tool, G.; Voy, D.

    1993-05-01

    The intent of the Accelerator System String Test (ASST) is to obtain data for model verification and information on the magnitudes of pressures and voltages encountered in an accelerator environment. The ASST milestone run was achieved during July and August, 1992 and consisted of demonstrating the accelerator components could be configured together as a system operating at full current. Following the milestone run, the string was warmed to counteract some design flaws that impeded the operational range. The string was again cooled to cryogenic temperatures in October, and a comprehensive power testing program was conducted through the end of January, 1993. This paper describes how the collider arc components operate in an accelerator environment during quenches induced by firing both strip heaters and spot heaters. Evaluation of the data illustrates how variations in the design parameters on magnets used in a string environment can impact system performance