Sharing cost in social community networks

DEFF Research Database (Denmark)

Pal, Ranjan; Elango, Divya; Wardana, Satya Ardhy

2012-01-01

their deployment in a residential locality. Our proposed mechanism accounts for heterogeneous user preferences towards different router features and comes up with the optimal (feature-set, user costs) router blueprint that satisfies each user in a locality, in turn motivating them to buy routers and thereby improve......Wireless social community networks (WSCNs) is an emerging technology that operate in the unlicensed spectrum and have been created as an alternative to cellular wireless networks for providing low-cost, high speed wireless data access in urban areas. WSCNs is an upcoming idea that is starting...... reflect their slow progress in capturing the WiFi router market. In this paper, we look at a router design and cost sharing problem in WSCNs to improve deployment. We devise a simple to implement, successful, budget-balanced, ex-post efficient, and individually rational auction-based mechanism...

Manufacturing enterprise’s logistics operational cost simulation and optimization from the perspective of inter-firm network

Directory of Open Access Journals (Sweden)

Chun Fu

2015-05-01

Full Text Available Purpose: By studying the case of a Changsha engineering machinery manufacturing firm, this paper aims to find out the optimization tactics to reduce enterprise’s logistics operational cost. Design/methodology/approach: This paper builds the structure model of manufacturing enterprise’s logistics operational costs from the perspective of inter-firm network and simulates the model based on system dynamics. Findings: It concludes that applying system dynamics in the research of manufacturing enterprise’s logistics cost control can better reflect the relationship of factors in the system. And the case firm can optimize the logistics costs by implement joint distribution. Research limitations/implications: This study still lacks comprehensive consideration about the variables quantities and quantitative of the control factors. In the future, we should strengthen the collection of data and information about the engineering manufacturing firms and improve the logistics operational cost model. Practical implications: This study puts forward some optimization tactics to reduce enterprise’s logistics operational cost. And it is of great significance for enterprise’s supply chain management optimization and logistics cost control. Originality/value: Differing from the existing literatures, this paper builds the structure model of manufacturing enterprise’s logistics operational costs from the perspective of inter-firm network and simulates the model based on system dynamics.

Unsupervised Neural Network Quantifies the Cost of Visual Information Processing.

Directory of Open Access Journals (Sweden)

Levente L Orbán

Full Text Available Untrained, "flower-naïve" bumblebees display behavioural preferences when presented with visual properties such as colour, symmetry, spatial frequency and others. Two unsupervised neural networks were implemented to understand the extent to which these models capture elements of bumblebees' unlearned visual preferences towards flower-like visual properties. The computational models, which are variants of Independent Component Analysis and Feature-Extracting Bidirectional Associative Memory, use images of test-patterns that are identical to ones used in behavioural studies. Each model works by decomposing images of floral patterns into meaningful underlying factors. We reconstruct the original floral image using the components and compare the quality of the reconstructed image to the original image. Independent Component Analysis matches behavioural results substantially better across several visual properties. These results are interpreted to support a hypothesis that the temporal and energetic costs of information processing by pollinators served as a selective pressure on floral displays: flowers adapted to pollinators' cognitive constraints.

Unsupervised Neural Network Quantifies the Cost of Visual Information Processing.

Science.gov (United States)

Orbán, Levente L; Chartier, Sylvain

2015-01-01

Untrained, "flower-naïve" bumblebees display behavioural preferences when presented with visual properties such as colour, symmetry, spatial frequency and others. Two unsupervised neural networks were implemented to understand the extent to which these models capture elements of bumblebees' unlearned visual preferences towards flower-like visual properties. The computational models, which are variants of Independent Component Analysis and Feature-Extracting Bidirectional Associative Memory, use images of test-patterns that are identical to ones used in behavioural studies. Each model works by decomposing images of floral patterns into meaningful underlying factors. We reconstruct the original floral image using the components and compare the quality of the reconstructed image to the original image. Independent Component Analysis matches behavioural results substantially better across several visual properties. These results are interpreted to support a hypothesis that the temporal and energetic costs of information processing by pollinators served as a selective pressure on floral displays: flowers adapted to pollinators' cognitive constraints.

Improved Cost-Base Design of Water Distribution Networks using Genetic Algorithm

Science.gov (United States)

Moradzadeh Azar, Foad; Abghari, Hirad; Taghi Alami, Mohammad; Weijs, Steven

2010-05-01

Population growth and progressive extension of urbanization in different places of Iran cause an increasing demand for primary needs. The water, this vital liquid is the most important natural need for human life. Providing this natural need is requires the design and construction of water distribution networks, that incur enormous costs on the country's budget. Any reduction in these costs enable more people from society to access extreme profit least cost. Therefore, investment of Municipal councils need to maximize benefits or minimize expenditures. To achieve this purpose, the engineering design depends on the cost optimization techniques. This paper, presents optimization models based on genetic algorithm(GA) to find out the minimum design cost Mahabad City's (North West, Iran) water distribution network. By designing two models and comparing the resulting costs, the abilities of GA were determined. the GA based model could find optimum pipe diameters to reduce the design costs of network. Results show that the water distribution network design using Genetic Algorithm could lead to reduction of at least 7% in project costs in comparison to the classic model. Keywords: Genetic Algorithm, Optimum Design of Water Distribution Network, Mahabad City, Iran.

Construction of road network vulnerability evaluation index based on general travel cost

Science.gov (United States)

Leng, Jun-qiang; Zhai, Jing; Li, Qian-wen; Zhao, Lin

2018-03-01

With the development of China's economy and the continuous improvement of her urban road network, the vulnerability of the urban road network has attracted increasing attention. Based on general travel cost, this work constructs the vulnerability evaluation index for the urban road network, and evaluates the vulnerability of the urban road network from the perspective of user generalised travel cost. Firstly, the generalised travel cost model is constructed based on vehicle cost, travel time, and traveller comfort. Then, the network efficiency index is selected as an evaluation index of vulnerability: the network efficiency index is composed of the traffic volume and the generalised travel cost, which are obtained from the equilibrium state of the network. In addition, the research analyses the influence of traffic capacity decrease, road section attribute value, and location of road section, on vulnerability. Finally, the vulnerability index is used to analyse the local area network of Harbin and verify its applicability.

Effects of network node consolidation in optical access and aggregation networks on costs and power consumption

Science.gov (United States)

Lange, Christoph; Hülsermann, Ralf; Kosiankowski, Dirk; Geilhardt, Frank; Gladisch, Andreas

2010-01-01

The increasing demand for higher bit rates in access networks requires fiber deployment closer to the subscriber resulting in fiber-to-the-home (FTTH) access networks. Besides higher access bit rates optical access network infrastructure and related technologies enable the network operator to establish larger service areas resulting in a simplified network structure with a lower number of network nodes. By changing the network structure network operators want to benefit from a changed network cost structure by decreasing in short and mid term the upfront investments for network equipment due to concentration effects as well as by reducing the energy costs due to a higher energy efficiency of large network sites housing a high amount of network equipment. In long term also savings in operational expenditures (OpEx) due to the closing of central office (CO) sites are expected. In this paper different architectures for optical access networks basing on state-of-the-art technology are analyzed with respect to network installation costs and power consumption in the context of access node consolidation. Network planning and dimensioning results are calculated for a realistic network scenario of Germany. All node consolidation scenarios are compared against a gigabit capable passive optical network (GPON) based FTTH access network operated from the conventional CO sites. The results show that a moderate reduction of the number of access nodes may be beneficial since in that case the capital expenditures (CapEx) do not rise extraordinarily and savings in OpEx related to the access nodes are expected. The total power consumption does not change significantly with decreasing number of access nodes but clustering effects enable a more energyefficient network operation and optimized power purchase order quantities leading to benefits in energy costs.

Designing Green Networks and Network Operations Saving Run-the-Engine Costs

CERN Document Server

Minoli, Daniel

2011-01-01

In recent years the confluence of socio-political trends toward environmental responsibility and the pressing need to reduce Run-the-Engine (RTE) costs has given birth to a nascent discipline of Green IT. A clear and concise introduction to green networks and green network operations, this book examines analytical measures and discusses virtualization, network computing, and web services as approaches for green data centers and networks. It identifies some strategies for green appliance and end devices and examines the methodical steps that can be taken over time to achieve a seamless migratio

Solving Minimum Cost Multi-Commodity Network Flow Problem ...

African Journals Online (AJOL)

ADOWIE PERE

2018-03-23

Mar 23, 2018 ... network-based modeling framework for integrated fixed and mobile ... Minimum Cost Network Flow Problem (MCNFP) and some ..... Unmanned Aerial Vehicle Routing in Traffic. Incident ... Ph.D. Thesis, Dept. of Surveying &.

On the origins of hierarchy in complex networks

Science.gov (United States)

Corominas-Murtra, Bernat; Goñi, Joaquín; Solé, Ricard V.; Rodríguez-Caso, Carlos

2013-01-01

Hierarchy seems to pervade complexity in both living and artificial systems. Despite its relevance, no general theory that captures all features of hierarchy and its origins has been proposed yet. Here we present a formal approach resulting from the convergence of theoretical morphology and network theory that allows constructing a 3D morphospace of hierarchies and hence comparing the hierarchical organization of ecological, cellular, technological, and social networks. Embedded within large voids in the morphospace of all possible hierarchies, four major groups are identified. Two of them match the expected from random networks with similar connectivity, thus suggesting that nonadaptive factors are at work. Ecological and gene networks define the other two, indicating that their topological order is the result of functional constraints. These results are consistent with an exploration of the morphospace, using in silico evolved networks. PMID:23898177

Cost-Based Vertical Handover Decision Algorithm for WWAN/WLAN Integrated Networks

Directory of Open Access Journals (Sweden)

Kim LaeYoung

2009-01-01

Full Text Available Abstract Next generation wireless communications are expected to rely on integrated networks consisting of multiple wireless technologies. Heterogeneous networks based on Wireless Local Area Networks (WLANs and Wireless Wide Area Networks (WWANs can combine their respective advantages on coverage and data rates, offering a high Quality of Service (QoS to mobile users. In such environment, multi-interface terminals should seamlessly switch from one network to another in order to obtain improved performance or at least to maintain a continuous wireless connection. Therefore, network selection algorithm is important in providing better performance to the multi-interface terminals in the integrated networks. In this paper, we propose a cost-based vertical handover decision algorithm that triggers the Vertical Handover (VHO based on a cost function for WWAN/WLAN integrated networks. For the cost function, we focus on developing an analytical model of the expected cost of WLAN for the mobile users that enter the double-coverage area while having a connection in the WWAN. Our simulation results show that the proposed scheme achieves better performance in terms of power consumption and throughput than typical approach where WLANs are always preferred whenever the WLAN access is available.

[Self-owned versus accredited network: comparative cost analysis in a Brazilian health insurance provider].

Science.gov (United States)

Souza, Marcos Antônio de; Salvalaio, Dalva

2010-10-01

to analyze the cost of a self-owned network maintained by a Brazilian health insurance provider as compared to the price charged by accredited service providers, so as to identify whether or not the self-owned network is economically advantageous. for this exploratory study, the company's management reports were reviewed. The cost associated with the self-owned network was calculated based on medical and dental office visits and diagnostic/laboratory tests performed at one of the company's most representative facilities. The costs associated with third parties were derived from price tables used by the accredited network for the same services analyzed in the self-owned network. The full-cost method was used for cost quantification. Costs are presented as absolute values (in R$) and percent comparisons between self-owned network costs versus accredited network costs. overall, the self-owned network was advantageous for medical and dental consultations as well as diagnostic and laboratory tests. Pediatric and labor medicine consultations and x-rays were less costly in the accredited network. the choice of verticalization has economic advantages for the health care insurance operator in comparison with services provided by third parties.

Determining the total cost of reverse supply chain operations for original equipment manufacturers

DEFF Research Database (Denmark)

Larsen, Samuel Brüning; Jacobsen, Peter

2014-01-01

When original equipment manufacturers (OEM) examine whether or not to invest in a reverse supply chain (RSC), managers need insight into not only the cost savings and new revenue streams the RSC enables, but also the total cost of the RSC itself. Using case study research the study examines what...... cost parameters constitute the total cost (TC) of the RSC. The specific RSC that the study seeks the TC for consists of 1) end-product refurbishing, 2) component refurbishing, and 3) sales of used materials back to original suppliers or independent recyclers for materials recycling....

[Cost estimation of an epidemiological surveillance network for animal diseases in Central Africa: a case study of the Chad network].

Science.gov (United States)

Ouagal, M; Berkvens, D; Hendrikx, P; Fecher-Bourgeois, F; Saegerman, C

2012-12-01

In sub-Saharan Africa, most epidemiological surveillance networks for animal diseases were temporarily funded by foreign aid. It should be possible for national public funds to ensure the sustainability of such decision support tools. Taking the epidemiological surveillance network for animal diseases in Chad (REPIMAT) as an example, this study aims to estimate the network's cost by identifying the various costs and expenditures for each level of intervention. The network cost was estimated on the basis of an analysis of the operational organisation of REPIMAT, additional data collected in surveys and interviews with network field workers and a market price listing for Chad. These costs were then compared with those of other epidemiological surveillance networks in West Africa. The study results indicate that REPIMAT costs account for 3% of the State budget allocated to the Ministry of Livestock. In Chad in general, as in other West African countries, fixed costs outweigh variable costs at every level of intervention. The cost of surveillance principally depends on what is needed for surveillance at the local level (monitoring stations) and at the intermediate level (official livestock sectors and regional livestock delegations) and on the cost of the necessary equipment. In African countries, the cost of surveillance per square kilometre depends on livestock density.

Network resilience against intelligent attacks constrained by the degree-dependent node removal cost

International Nuclear Information System (INIS)

Annibale, A; Coolen, A C C; Bianconi, G

2010-01-01

We study the resilience of complex networks against attacks in which nodes are targeted intelligently, but where disabling a node has a cost to the attacker which depends on its degree. Attackers have to meet these costs with limited resources, which constrains their actions. A network's integrity is quantified in terms of the efficacy of the process that it supports. We calculate how the optimal attack strategy and the most attack-resistant network degree statistics depend on the node removal cost function and the attack resources. The resilience of networks against intelligent attacks is found to depend strongly on the node removal cost function faced by the attacker. In particular, if node removal costs increase sufficiently fast with the node degree, power law networks are found to be more resilient than Poissonian ones, even against optimized intelligent attacks. For cost functions increasing quadratically in the node degrees, intelligent attackers cannot damage the network more than random damages would.

Strategy on energy saving reconstruction of distribution networks based on life cycle cost

Science.gov (United States)

Chen, Xiaofei; Qiu, Zejing; Xu, Zhaoyang; Xiao, Chupeng

2017-08-01

Because the actual distribution network reconstruction project funds are often limited, the cost-benefit model and the decision-making method are crucial for distribution network energy saving reconstruction project. From the perspective of life cycle cost (LCC), firstly the research life cycle is determined for the energy saving reconstruction of distribution networks with multi-devices. Then, a new life cycle cost-benefit model for energy-saving reconstruction of distribution network is developed, in which the modification schemes include distribution transformers replacement, lines replacement and reactive power compensation. In the operation loss cost and maintenance cost area, the operation cost model considering the influence of load season characteristics and the maintenance cost segmental model of transformers are proposed. Finally, aiming at the highest energy saving profit per LCC, a decision-making method is developed while considering financial and technical constraints as well. The model and method are applied to a real distribution network reconstruction, and the results prove that the model and method are effective.

Origin of hyperbolicity in brain-to-brain coordination networks

Science.gov (United States)

Tadić, Bosiljka; Andjelković, Miroslav; Šuvakov, Milovan

2018-02-01

Hyperbolicity or negative curvature of complex networks is the intrinsic geometric proximity of nodes in the graph metric space, which implies an improved network function. Here, we investigate hidden combinatorial geometries in brain-to-brain coordination networks arising through social communications. The networks originate from correlations among EEG signals previously recorded during spoken communications comprising of 14 individuals with 24 speaker-listener pairs. We find that the corresponding networks are delta-hyperbolic with delta_max=1 and the graph diameter D=3 in each brain. While the emergent hyperbolicity in the two-brain networks satisfies delta_max/D/2 neuronal correlation patterns ranging from weak coordination to super-brain structure. These topology features are in qualitative agreement with the listener’s self-reported ratings of own experience and quality of the speaker, suggesting that studies of the cross-brain connector networks can reveal new insight into the neural mechanisms underlying human social behavior.

Network formation under heterogeneous costs: The multiple group model

NARCIS (Netherlands)

Kamphorst, J.J.A.; van der Laan, G.

2007-01-01

It is widely recognized that the shape of networks influences both individual and aggregate behavior. This raises the question which types of networks are likely to arise. In this paper we investigate a model of network formation, where players are divided into groups and the costs of a link between

Accounting for Energy Cost When Designing Energy-Efficient Wireless Access Networks

Directory of Open Access Journals (Sweden)

Greta Vallero

2018-03-01

Full Text Available Because of the increase of the data traffic demand, wireless access networks, through which users access telecommunication services, have expanded, in terms of size and of capability and, consequently, in terms of power consumption. Therefore, costs to buy the necessary power for the supply of base stations of those networks is becoming very high, impacting the communication cost. In this study, strategies to reduce the amount of money spent for the purchase of the energy consumed by the base stations are proposed for a network powered by solar panels, energy batteries and the power grid. First, the variability of the energy prices is exploited. It provides a cost reduction of up to 30%, when energy is bought in advance. If a part of the base stations is deactivated when the energy price is higher than a given threshold, a compromise between the energy cost and the user coverage drop is needed. In the simulated scenario, the necessary energy cost can be reduced by more than 40%, preserving the user coverage by greater than 94%. Second, the network is introduced to the energy market: it buys and sells energy from/to the traditional power grid. Finally, costs are reduced by the reduction of power consumption of the network, achieved by using microcell base stations. In the considered scenario, up to a 31% cost reduction is obtained, without the deterioration of the quality of service, but a huge Capex expenditure is required.

Behaviour in O of the Neural Networks Training Cost

DEFF Research Database (Denmark)

Goutte, Cyril

1998-01-01

We study the behaviour in zero of the derivatives of the cost function used when training non-linear neural networks. It is shown that a fair number offirst, second and higher order derivatives vanish in zero, validating the belief that 0 is a peculiar and potentially harmful location. These calc......We study the behaviour in zero of the derivatives of the cost function used when training non-linear neural networks. It is shown that a fair number offirst, second and higher order derivatives vanish in zero, validating the belief that 0 is a peculiar and potentially harmful location....... These calculations arerelated to practical and theoretical aspects of neural networks training....

Cost allocation model for distribution networks considering high penetration of distributed energy resources

DEFF Research Database (Denmark)

Soares, Tiago; Pereira, Fábio; Morais, Hugo

2015-01-01

The high penetration of distributed energy resources (DER) in distribution networks and the competitive environment of electricity markets impose the use of new approaches in several domains. The network cost allocation, traditionally used in transmission networks, should be adapted and used...... in the distribution networks considering the specifications of the connected resources. The main goal is to develop a fairer methodology trying to distribute the distribution network use costs to all players which are using the network in each period. In this paper, a model considering different type of costs (fixed......, losses, and congestion costs) is proposed comprising the use of a large set of DER, namely distributed generation (DG), demand response (DR) of direct load control type, energy storage systems (ESS), and electric vehicles with capability of discharging energy to the network, which is known as vehicle...

Heterogeneous Deployment Analysis for Cost-Effective Mobile Network Evolution

DEFF Research Database (Denmark)

Coletti, Claudio

2013-01-01

network coverage and boosting network capacity in traffic hot-spot areas. The thesis deals with the deployment of both outdoor small cells and indoor femto cells. Amongst the outdoor solution, particular emphasis is put on relay base stations as backhaul costs can be reduced by utilizing LTE spectrum...... statistical models of deployment areas, the performance analysis is carried out in the form of operator case studies for large-scale deployment scenarios, including realistic macro network layouts and inhomogeneous spatial traffic distributions. Deployment of small cells is performed by means of proposed...... heuristic deployment algorithms, which combine network coverage and spatial user density information. As a secondary aspect, deployment solutions achieving the same coverage performance are compared in terms of Total Cost of Ownership (TCO), in order to investigate the viability of different deployment...

The influence of network characteristics on costs in pharmaceutical new product development

DEFF Research Database (Denmark)

Buonansegna, Erika; Schultz, Carsten; Stargardt, Tom

2015-01-01

This paper develops a model relating prior experiences, network stability, exclusive partnership, geographical distance, and intermediation in inter-firm R&D networks to new product development (NPD) costs. The developed hypotheses are tested with unique multilevel R&D partnership data from 33...... becomes relevant for non-exclusive partnerships and dispersed networks. NPD costs also increase in more stable networks, reflecting the relevance of structural holes for control and information advantages. This study contributes to the network management literature by understanding the relation between...

Neural networks applied to discriminate botanical origin of honeys.

Science.gov (United States)

Anjos, Ofélia; Iglesias, Carla; Peres, Fátima; Martínez, Javier; García, Ángela; Taboada, Javier

2015-05-15

The aim of this work is develop a tool based on neural networks to predict the botanical origin of honeys using physical and chemical parameters. The managed database consists of 49 honey samples of 2 different classes: monofloral (almond, holm oak, sweet chestnut, eucalyptus, orange, rosemary, lavender, strawberry trees, thyme, heather, sunflower) and multifloral. The moisture content, electrical conductivity, water activity, ashes content, pH, free acidity, colorimetric coordinates in CIELAB space (L(∗), a(∗), b(∗)) and total phenols content of the honey samples were evaluated. Those properties were considered as input variables of the predictive model. The neural network is optimised through several tests with different numbers of neurons in the hidden layer and also with different input variables. The reduced error rates (5%) allow us to conclude that the botanical origin of honey can be reliably and quickly known from the colorimetric information and the electrical conductivity of honey. Copyright © 2014 Elsevier Ltd. All rights reserved.

An efficient and cost effective nuclear medicine image network

International Nuclear Information System (INIS)

Sampathkumaran, K.S.; Miller, T.R.

1987-01-01

An image network that is in use in a large nuclear medicine department is described. This network was designed to efficiently handle a large volume of clinical data at reasonable cost. Small, limited function computers are attached to each scintillation camera for data acquisition. The images are transferred by cable network or floppy disc to a large, powerful central computer for processing and display. Cost is minimized by use of small acquisition computers not equipped with expensive video display systems or elaborate analysis software. Thus, financial expenditure can be concentrated in a powerful central computer providing a centralized data base, rapid processing, and an efficient environment for program development. Clinical work is greatly facilitated because the physicians can process and display all studies without leaving the main reading area. (orig.)

Least-cost network evaluation of centralized and decentralized contributions to global electrification

International Nuclear Information System (INIS)

Levin, Todd; Thomas, Valerie M.

2012-01-01

The choice between centralized and decentralized electricity generation is examined for 150 countries as a function of population distribution, electricity consumption, transmission cost, and the cost difference between decentralized and centralized electricity generation. A network algorithm is developed to find the shortest centralized transmission network that spans a given fraction of the population in a country. The least-cost combination of centralized and decentralized electricity that serves the country is determined. Case studies of Botswana, Uganda, and Bangladesh illustrate situations that are more and less suited for decentralized electrification. Specific maps for centralized and decentralized generation are presented to show how the least-cost option varies with the relative costs of centralized and decentralized generation and transmission cost. Centralized and decentralized fractions are calculated for 150 countries. For most of the world's population, centralized electricity is the least-cost option. For a number of countries, particularly in Africa, substantial populations and regions may be most cost-effectively served by decentralized electricity. - Highlights: ► Centralized and decentralized electrification are compared for 150 countries. ► A cost-optimized network algorithm finds the least-cost electrification system. ► Least-cost infrastructures combine centralized and decentralized portions. ► For most people, centralized electricity is cheapest option. ► In much of Africa, decentralized electricity may be cheaper than centralized.

Smart control for minimizing distribution network reinforcement cost due to electrification

International Nuclear Information System (INIS)

Pudjianto, Danny; Djapic, Predrag; Aunedi, Marko; Gan, Chin Kim; Strbac, Goran; Huang, Sikai; Infield, David

2013-01-01

Electrification of transport fleets and heating sectors is seen as one of the key strategies to further reduce the use of fossil fuels and the resulting greenhouse gas emissions. However, it will potentially cause a significant increase of electricity peak demand and have adverse consequences on the electricity system, in particular on distribution networks. This paper will address the benefits of various applications of smart network control and demand response technologies for enhancing the integration of these future load categories, and for improvements in operation management and efficient use of distribution network assets. A range of numerical simulations have been carried out on different distribution network topologies (rural and urban networks) to identify the need and the cost of network reinforcement required to accommodate future load under various operating strategies such as Business as Usual (passive demand and passive network) against the smart grid approach. Applications of smart Plug-in vehicle (PiV) charging, smart heat pumps, and optimised control of network voltage regulators to reduce network investment have been studied, and selected key results of our studies on evaluating the benefits of implementing these technologies for Great Britain's distribution networks are presented and discussed in this paper. - Highlights: ► Growth of electricity loads driven by electrification of transport and heat will be significant. ► It will increase the electricity peak demand up to 2–3 times and cost tens of billion pounds if we maintain Business as Usual approach. ► A coordinated application of smart demand technologies can significantly reduce this cost. ► It requires sets of policies and regulations to facilitate timely deployment of such technologies.

Testing the Feasibility of a Low-Cost Network Performance Measurement Infrastructure

Energy Technology Data Exchange (ETDEWEB)

Chevalier, Scott [Indiana Univ., Bloomington, IN (United States). International Networks; Schopf, Jennifer M. [Indiana Univ., Bloomington, IN (United States). International Networks; Miller, Kenneth [Pennsylvania State Univ., University Park, PA (United States). Telecommunications and Networking Services; Zurawski, Jason [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Energy Sciences Network

2016-07-01

Todays science collaborations depend on reliable, high performance networks, but monitoring the end-to-end performance of a network can be costly and difficult. The most accurate approaches involve using measurement equipment in many locations, which can be both expensive and difficult to manage due to immobile or complicated assets. The perfSONAR framework facilitates network measurement making management of the tests more reasonable. Traditional deployments have used over-provisioned servers, which can be expensive to deploy and maintain. As scientific network uses proliferate, there is a desire to instrument more facets of a network to better understand trends. This work explores low cost alternatives to assist with network measurement. Benefits include the ability to deploy more resources quickly, and reduced capital and operating expenditures. Finally, we present candidate platforms and a testing scenario that evaluated the relative merits of four types of small form factor equipment to deliver accurate performance measurements.

Guaranteed Cost Fault-Tolerant Control for Networked Control Systems with Sensor Faults

Directory of Open Access Journals (Sweden)

Qixin Zhu

2015-01-01

Full Text Available For the large scale and complicated structure of networked control systems, time-varying sensor faults could inevitably occur when the system works in a poor environment. Guaranteed cost fault-tolerant controller for the new networked control systems with time-varying sensor faults is designed in this paper. Based on time delay of the network transmission environment, the networked control systems with sensor faults are modeled as a discrete-time system with uncertain parameters. And the model of networked control systems is related to the boundary values of the sensor faults. Moreover, using Lyapunov stability theory and linear matrix inequalities (LMI approach, the guaranteed cost fault-tolerant controller is verified to render such networked control systems asymptotically stable. Finally, simulations are included to demonstrate the theoretical results.

The calculation of costs of postal network and universal postal service based on standard and average cost principles

Directory of Open Access Journals (Sweden)

Blagojević Mladenka Z.

2017-01-01

Full Text Available The provision of universal postal service involves high costs for operator, especially in rural areas. The aim of this paper is to propose and test tool for managing the cost of providing universal postal service and maintaining the postal network in order to facilitate understanding of the problem in the sector. The proposed approach use standard prices and standard quantities (the redefined number of postal units, the number of employees, etc. as well as average costs for calculation of the costs of the universal postal service and postal network. The methodology provides the efficiency analysis, benchmarking and identification of causes of poor performance of management and resource allocation. It can be used for postal operators that do not have modern accounting systems.

Coordination and Lock-In: Competition with Switching Costs and Network Effects

OpenAIRE

Farrell, Joseph; Klemperer, Paul

2006-01-01

Switching costs and network effects bind customers to vendors if products are incompatible, locking customers or even markets in to early choices. Lock-in hinders customers from changing suppliers in response to (predictable or unpredictable) changes in efficiency, and gives vendors lucrative ex post market power—over the same buyer in the case of switching costs (or brand loyalty), or over others with network effects. Firms compete ex ante for this ex post power, using penetration ...

A case study to estimate costs using Neural Networks and regression based models

Directory of Open Access Journals (Sweden)

Nadia Bhuiyan

2012-07-01

Full Text Available Bombardier Aerospace’s high performance aircrafts and services set the utmost standard for the Aerospace industry. A case study in collaboration with Bombardier Aerospace is conducted in order to estimate the target cost of a landing gear. More precisely, the study uses both parametric model and neural network models to estimate the cost of main landing gears, a major aircraft commodity. A comparative analysis between the parametric based model and those upon neural networks model will be considered in order to determine the most accurate method to predict the cost of a main landing gear. Several trials are presented for the design and use of the neural network model. The analysis for the case under study shows the flexibility in the design of the neural network model. Furthermore, the performance of the neural network model is deemed superior to the parametric models for this case study.

Topological Origin of the Network Dilation Anomaly in Ion-Exchanged Glasses

Science.gov (United States)

Wang, Mengyi; Smedskjaer, Morten M.; Mauro, John C.; Sant, Gaurav; Bauchy, Mathieu

2017-11-01

Ion exchange is commonly used to strengthen oxide glasses. However, the resulting stuffed glasses usually do not reach the molar volume of as-melted glasses of similar composition—a phenomenon known as the network dilation anomaly. This behavior seriously limits the potential for the chemical strengthening of glasses and its origin remains one of the mysteries of glass science. Here, based on molecular dynamics simulations of sodium silicate glasses coupled with topological constraint theory, we show that the topology of the atomic network controls the extent of ion-exchange-induced dilation. We demonstrate that isostatic glasses do not show any network dilation anomaly. This is found to arise from the combined absence of floppy modes of deformation and internal eigenstress in isostatic atomic networks.

Energy Cost Minimization in Heterogeneous Cellular Networks with Hybrid Energy Supplies

Directory of Open Access Journals (Sweden)

Bang Wang

2016-01-01

Full Text Available The ever increasing data demand has led to the significant increase of energy consumption in cellular mobile networks. Recent advancements in heterogeneous cellular networks and green energy supplied base stations provide promising solutions for cellular communications industry. In this article, we first review the motivations and challenges as well as approaches to address the energy cost minimization problem for such green heterogeneous networks. Owing to the diversities of mobile traffic and renewable energy, the energy cost minimization problem involves both temporal and spatial optimization of resource allocation. We next present a new solution to illustrate how to combine the optimization of the temporal green energy allocation and spatial mobile traffic distribution. The whole optimization problem is decomposed into four subproblems, and correspondingly our proposed solution is divided into four parts: energy consumption estimation, green energy allocation, user association, and green energy reallocation. Simulation results demonstrate that our proposed algorithm can significantly reduce the total energy cost.

Origin of the cosmic network in ΛCDM: Nature vs nurture

International Nuclear Information System (INIS)

Shandarin, Sergei; Habib, Salman; Heitmann, Katrin

2010-01-01

The large-scale structure of the Universe, as traced by the distribution of galaxies, is now being revealed by large-volume cosmological surveys. The structure is characterized by galaxies distributed along filaments, the filaments connecting in turn to form a percolating network. Our objective here is to quantitatively specify the underlying mechanisms that drive the formation of the cosmic network: By combining percolation-based analyses with N-body simulations of gravitational structure formation, we elucidate how the network has its origin in the properties of the initial density field (nature) and how its contrast is then amplified by the nonlinear mapping induced by the gravitational instability (nurture).

Origin of the cosmic network in ΛCDM: Nature vs nurture

Science.gov (United States)

Shandarin, Sergei; Habib, Salman; Heitmann, Katrin

2010-05-01

The large-scale structure of the Universe, as traced by the distribution of galaxies, is now being revealed by large-volume cosmological surveys. The structure is characterized by galaxies distributed along filaments, the filaments connecting in turn to form a percolating network. Our objective here is to quantitatively specify the underlying mechanisms that drive the formation of the cosmic network: By combining percolation-based analyses with N-body simulations of gravitational structure formation, we elucidate how the network has its origin in the properties of the initial density field (nature) and how its contrast is then amplified by the nonlinear mapping induced by the gravitational instability (nurture).

Incremental Optimization of Hub and Spoke Network for the Spokes’ Numbers and Flow

Directory of Open Access Journals (Sweden)

Yanfeng Wang

2015-01-01

Full Text Available Hub and spoke network problem is solved as part of a strategic decision making process which may have a profound effect on the future of enterprises. In view of the existing network structure, as time goes on, the number of spokes and the flow change because of different sources of uncertainty. Hence, the incremental optimization of hub and spoke network problem is considered in this paper, and the policy makers should adopt a series of strategies to cope with the change, such as setting up new hubs, adjusting the capacity level of original hubs, or closing some original hubs. The objective is to minimize the total cost, which includes the setup costs for the new hubs, the closure costs, and the adjustment costs for the original hubs as well as the flow routing costs. Two mixed-integer linear programming formulations are proposed and analyzed for this problem. China Deppon Logistics as an example is performed to present computational analysis, and we analyze the changes in the solutions driven by the number of spokes and the flow. The tests also allow an analysis to consider the effect of variation in parameters on network.

Robust and Cost-Efficient Communication Based on SNMP in Mobile Networks

Science.gov (United States)

Ryu, Sang-Hoon; Baik, Doo-Kwon

A main challenge in the design of this mobile network is the development of dynamic routing protocols that can efficiently find routes between two communicating nodes. Multimedia streaming services are receiving considerable interest in the mobile network business. An entire mobile network may change its point of attachment to the Internet. The mobile network is operated by a basic specification to support network mobility called Network Mobility (NEMO) Basic Support. However, NEMO basic Support mechanism has some problem in continuous communication. In this paper, we propose robust and cost-efficient algorithm. And we simulate proposed method and conclude some remarks.

Rules of origin and development of regional production network in ...

International Development Research Centre (IDRC) Digital Library (Canada)

Simpler Rules of Origin (RoO) with product specific rules can act as a catalyst in trade even if tariff rates are not low. Sector specific restrictiveness across trade agreements are assessed, in view of potential growth of International production networks (IPN). RoO is shown to play a significant role in promoting IPN.

Co-ordination and Lock-in: Competition with Switching Costs and Network Effects

OpenAIRE

Joseph Farrell; Paul Klemperer

2006-01-01

Switching costs and network effects bind customers to vendors if products are incompatible, locking customers or even markets in to early choices. Lock-in hinders customers from changing suppliers in response to (predictable or unpredictable) changes in effciency, and gives vendors lucrative ex post market power-over the same buyer in the case of switching costs (or brand loyalty), or over others with network effects. Firms compete ex ante for this ex post power, using penetration pricing, in...

Research on Japanese-original Anime Words based on Chinese Network Catchword Sphere

OpenAIRE

Cai Jin Chang

2016-01-01

In this paper, the phenomenon of Japanese-original anime language’s spreading in Chinese network language was discussed, and some theory of lexicology, semantics, grammar, and cultural linguistics was proposed. The characters of its different types and its influence on Chinese and the reason why the anime language can be so popular in the factors of psychologies, social also was analyzed. According to these studies, some suggestions were put forward that how to standardize the network languag...

On the Social Cost of Distributed Selfish Content Replication

DEFF Research Database (Denmark)

Pollatos, Gerasimos G.; Telelis, Orestis A.; Zissimopoulos, Vassilis

2008-01-01

We study distributed content replication networks formed voluntarily by selfish autonomous users, seeking access to information objects that originate form distant servers. Each user caters to minimization of its individual access cost by replicating locally (up to constrained storage capacity......) a subset of objects, and accessing the rest form the nearest possible location. We show existence of stable networks by proving existence of pure strategy Nash equilibria for a game-theoretic formulation of this situation. Social (overall) cost of stable networks is measured by the average...... or by the maximum access cost experienced by any user. We study socially most and least expensive stable networks by means of tight bounds on the ratios of the Price of Anarchy and Stability respectively. Although in the worst case the ratios may coincide, we identify cases where they differ significantly. We...

Computational cost for detecting inspiralling binaries using a network of laser interferometric detectors

International Nuclear Information System (INIS)

Pai, Archana; Bose, Sukanta; Dhurandhar, Sanjeev

2002-01-01

We extend a coherent network data-analysis strategy developed earlier for detecting Newtonian waveforms to the case of post-Newtonian (PN) waveforms. Since the PN waveform depends on the individual masses of the inspiralling binary, the parameter-space dimension increases by one from that of the Newtonian case. We obtain the number of templates and estimate the computational costs for PN waveforms: for a lower mass limit of 1M o-dot , for LIGO-I noise and with 3% maximum mismatch, the online computational speed requirement for single detector is a few Gflops; for a two-detector network it is hundreds of Gflops and for a three-detector network it is tens of Tflops. Apart from idealistic networks, we obtain results for realistic networks comprising of LIGO and VIRGO. Finally, we compare costs incurred in a coincidence detection strategy with those incurred in the coherent strategy detailed above

[The Identification of the Origin of Chinese Wolfberry Based on Infrared Spectral Technology and the Artificial Neural Network].

Science.gov (United States)

Li, Zhong; Liu, Ming-de; Ji, Shou-xiang

2016-03-01

The Fourier Transform Infrared Spectroscopy (FTIR) is established to find the geographic origins of Chinese wolfberry quickly. In the paper, the 45 samples of Chinese wolfberry from different places of Qinghai Province are to be surveyed by FTIR. The original data matrix of FTIR is pretreated with common preprocessing and wavelet transform. Compared with common windows shifting smoothing preprocessing, standard normal variation correction and multiplicative scatter correction, wavelet transform is an effective spectrum data preprocessing method. Before establishing model through the artificial neural networks, the spectra variables are compressed by means of the wavelet transformation so as to enhance the training speed of the artificial neural networks, and at the same time the related parameters of the artificial neural networks model are also discussed in detail. The survey shows even if the infrared spectroscopy data is compressed to 1/8 of its original data, the spectral information and analytical accuracy are not deteriorated. The compressed spectra variables are used for modeling parameters of the backpropagation artificial neural network (BP-ANN) model and the geographic origins of Chinese wolfberry are used for parameters of export. Three layers of neural network model are built to predict the 10 unknown samples by using the MATLAB neural network toolbox design error back propagation network. The number of hidden layer neurons is 5, and the number of output layer neuron is 1. The transfer function of hidden layer is tansig, while the transfer function of output layer is purelin. Network training function is trainl and the learning function of weights and thresholds is learngdm. net. trainParam. epochs=1 000, while net. trainParam. goal = 0.001. The recognition rate of 100% is to be achieved. It can be concluded that the method is quite suitable for the quick discrimination of producing areas of Chinese wolfberry. The infrared spectral analysis technology

Cost effectiveness of DH-network construction. Final report; Kaukolaempoeverkon rakentamisen kehittaeminen; Loppuraportti

Energy Technology Data Exchange (ETDEWEB)

Kivistoe, V.M. [Ekono Energy Ltd, Espoo (Finland)

1993-12-31

Construction cost of DH networks were analyzed in the study. Basing on the analysis, those areas of construction activities were selected, where cost effectiveness could be improved. According to the study, the civil works` cost form about half of the total construction cost on small diameter networks and 30..40 % of the cost of larger sizes. The impact of the design on the construction cost should be emphasized. According to the study it is possible to find significant reduction in the construction cost by increased use of twin pipe where the both carrier pipes are included in the same insulation casing. In small network sizes the reduction of cost achievable by the above is about 30..35 % and in larger sizes about 10 % (DN 125..DN 200) when comparing with a design by individual pipes. The use of twin pipe also causes savings in thermal loss. In sizes DN 65 and up, the saving in heat loss is about 90..95 FIM/m which represents about half of the total savings when compared with design by individual pipes. The possibility of prestressing the twin pipe element at factory in order to shorten the installation time at site was also studied and test pipes was also done. By factory prestressing it would be possible to avoid preheating of pipes at construction site. The trench could be backfilled immediately after pipe laying, welding and inspections. Theoretically and based on test pipes done the prestressing of twin pipe element looks very promising. When factory prestressing would be used, the open time of the trench is reduced significantly and for instance the disturbance to traffic is smaller. As well the use of labour and machinery at site could be more effective

Evaluating C-RAN Fronthaul Functional Splits in Terms of Network Level Energy and Cost Savings

DEFF Research Database (Denmark)

Checko, Aleksandra; Popovska Avramova, Andrijana; Berger, Michael Stübert

2016-01-01

The placement of the complete baseband processing in a centralized pool results in high data rate requirement and inflexibility of the fronthaul network, which challenges the energy and cost effectiveness of the cloud radio access network (C-RAN). Recently, redesign of the C-RAN through functional...... split in the baseband processing chain has been proposed to overcome these challenges. This paper evaluates, by mathematical and simulation methods, different splits with respect to network level energy and cost efficiency having in the mind the expected quality of service.The proposed mathematical...... model quantifies the multiplexing gains and the trade-offs between centralization and decentralization concerning the cost of the pool, fronthaul network capacity and resource utilization. The event-based simulation captures the influence of the traffic load dynamics and traffic type variation...

Research on Japanese-original Anime Words based on Chinese Network Catchword Sphere

Directory of Open Access Journals (Sweden)

Cai Jin Chang

2016-01-01

Full Text Available In this paper, the phenomenon of Japanese-original anime language’s spreading in Chinese network language was discussed, and some theory of lexicology, semantics, grammar, and cultural linguistics was proposed. The characters of its different types and its influence on Chinese and the reason why the anime language can be so popular in the factors of psychologies, social also was analyzed. According to these studies, some suggestions were put forward that how to standardize the network language and how to raise its taste.

Computational cost for detecting inspiralling binaries using a network of laser interferometric detectors

CERN Document Server

Pai, A; Dhurandhar, S V

2002-01-01

We extend a coherent network data-analysis strategy developed earlier for detecting Newtonian waveforms to the case of post-Newtonian (PN) waveforms. Since the PN waveform depends on the individual masses of the inspiralling binary, the parameter-space dimension increases by one from that of the Newtonian case. We obtain the number of templates and estimate the computational costs for PN waveforms: for a lower mass limit of 1M sub o sub - sub d sub o sub t , for LIGO-I noise and with 3% maximum mismatch, the online computational speed requirement for single detector is a few Gflops; for a two-detector network it is hundreds of Gflops and for a three-detector network it is tens of Tflops. Apart from idealistic networks, we obtain results for realistic networks comprising of LIGO and VIRGO. Finally, we compare costs incurred in a coincidence detection strategy with those incurred in the coherent strategy detailed above.

Coevolution of Synchronization and Cooperation in Costly Networked Interactions

Science.gov (United States)

Antonioni, Alberto; Cardillo, Alessio

2017-06-01

Despite the large number of studies on synchronization, the hypothesis that interactions bear a cost for involved individuals has seldom been considered. The introduction of costly interactions leads, instead, to the formulation of a dichotomous scenario in which an individual may decide to cooperate and pay the cost in order to get synchronized with the rest of the population. Alternatively, the same individual can decide to free ride, without incurring any cost, waiting for others to get synchronized to his or her state. Thus, the emergence of synchronization may be seen as the byproduct of an evolutionary game in which individuals decide their behavior according to the benefit-to-cost ratio they accrued in the past. We study the onset of cooperation and synchronization in networked populations of Kuramoto oscillators and report how topology is essential in order for cooperation to thrive. We also display how different classes of topology foster synchronization differently both at microscopic and macroscopic levels.

Switching Fuzzy Guaranteed Cost Control for Nonlinear Networked Control Systems

Directory of Open Access Journals (Sweden)

Linqin Cai

2014-01-01

Full Text Available This paper deals with the problem of guaranteed cost control for a class of nonlinear networked control systems (NCSs with time-varying delay. A guaranteed cost controller design method is proposed to achieve the desired control performance based on the switched T-S fuzzy model. The switching mechanism is introduced to handle the uncertainties of NCSs. Based on Lyapunov functional approach, some sufficient conditions for the existence of state feedback robust guaranteed cost controller are presented. Simulation results show that the proposed method is effective to guarantee system’s global asymptotic stability and quality of service (QoS.

Cost Minimization Model of Gas Transmission Line for Indonesian SIJ Pipeline Network

Directory of Open Access Journals (Sweden)

Septoratno Siregar

2003-05-01

Full Text Available Optimization of Indonesian SIJ gas pipeline network is being discussed here. Optimum pipe diameters together with the corresponding pressure distribution are obtained from minimization of total cost function consisting of investment and operating costs and subjects to some physical (Panhandle A and Panhandle B equations constraints. Iteration technique based on Generalized Steepest-Descent and fourth order Runge-Kutta method are used here. The resulting diameters from this continuous optimization are then rounded to the closest available discrete sizes. We have also calculated toll fee along each segment and safety factor of the network by determining the pipe wall thickness, using ANSI B31.8 standard. Sensitivity analysis of toll fee for variation of flow rates is shown here. The result will gives the diameter and compressor size and compressor location that feasible to use for the SIJ pipeline project. The Result also indicates that the east route cost relatively less expensive than the west cost.

Network cost in transmission and distribution of electric power

International Nuclear Information System (INIS)

Lindahl, A.; Naeslund, B.; Oettinger-Biberg, C.; Olander, H.; Wuolikainen, T.; Fritz, P.

1994-01-01

This report is divided in two parts, where part 1 treats the charges on the regional nets with special emphasis on the net owners tariffs on a deregulated market. Part 2 describes the development of the network costs in electric power distribution for the period 1991-1993. 11 figs, 33 tabs

Guaranteed cost control of mobile sensor networks with Markov switching topologies.

Science.gov (United States)

Zhao, Yuan; Guo, Ge; Ding, Lei

2015-09-01

This paper investigates the consensus seeking problem of mobile sensor networks (MSNs) with random switching topologies. The network communication topologies are composed of a set of directed graphs (or digraph) with a spanning tree. The switching of topologies is governed by a Markov chain. The consensus seeking problem is addressed by introducing a global topology-aware linear quadratic (LQ) cost as the performance measure. By state transformation, the consensus problem is transformed to the stabilization of a Markovian jump system with guaranteed cost. A sufficient condition for global mean-square consensus is derived in the context of stochastic stability analysis of Markovian jump systems. A computational algorithm is given to synchronously calculate both the sub-optimal consensus controller gains and the sub-minimum upper bound of the cost. The effectiveness of the proposed design method is illustrated by three numerical examples. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

Low cost drip irrigation in Burkina Faso : unravelling actors, networks and practices

NARCIS (Netherlands)

Wanvoeke, M.J.V.

2015-01-01

Title: Low cost drip irrigation in Burkina Faso: Unravelling Actors, Networks and Practices

In Burkina Faso, there is a lot of enthusiasm about Low Cost Drip Irrigation (LCDI) as a tool to irrigate vegetables, and thus improve food security,

Inclusion of tank configurations as a variable in the cost optimization of branched piped-water networks

Science.gov (United States)

Hooda, Nikhil; Damani, Om

2017-06-01

The classic problem of the capital cost optimization of branched piped networks consists of choosing pipe diameters for each pipe in the network from a discrete set of commercially available pipe diameters. Each pipe in the network can consist of multiple segments of differing diameters. Water networks also consist of intermediate tanks that act as buffers between incoming flow from the primary source and the outgoing flow to the demand nodes. The network from the primary source to the tanks is called the primary network, and the network from the tanks to the demand nodes is called the secondary network. During the design stage, the primary and secondary networks are optimized separately, with the tanks acting as demand nodes for the primary network. Typically the choice of tank locations, their elevations, and the set of demand nodes to be served by different tanks is manually made in an ad hoc fashion before any optimization is done. It is desirable therefore to include this tank configuration choice in the cost optimization process itself. In this work, we explain why the choice of tank configuration is important to the design of a network and describe an integer linear program model that integrates the tank configuration to the standard pipe diameter selection problem. In order to aid the designers of piped-water networks, the improved cost optimization formulation is incorporated into our existing network design system called JalTantra.

Potential impacts of the Alberta fetal alcohol spectrum disorder service networks on secondary disabilities: a cost-benefit analysis.

Science.gov (United States)

Thanh, Nguyen Xuan; Moffatt, Jessica; Jacobs, Philip; Chuck, Anderson W; Jonsson, Egon

2013-01-01

To estimate the break-even effectiveness of the Alberta Fetal Alcohol Spectrum Disorder (FASD) Service Networks in reducing occurrences of secondary disabilities associated with FASD. The secondary disabilities addressed within this study include crime, homelessness, mental health problems, and school disruption (for children) or unemployment (for adults). We used a cost-benefit analysis approach where benefits of the service networks were the cost difference between the two approaches: having the 12 service networks and having no service network in place, across Alberta. We used a threshold analysis to estimate the break-even effectiveness (i.e. the effectiveness level at which the service networks became cost-saving). If no network was in place throughout the province, the secondary disabilities would cost $22.85 million (including $8.62 million for adults and $14.24 million for children) per year. Given the cost of network was $6.12 million per year, the break-even effectiveness was estimated at 28% (range: 25% to 32%). Although not all benefits associated with the service networks are included, such as the exclusion of the primary benefit to those experiencing FASD, the benefits to FASD caregivers, and the preventative benefits, the economic and social burden associated with secondary disabilities will "pay-off" if the effectiveness of the program in reducing secondary disabilities is 28%.

Low-cost airlines in Europe: Network structures after the enlargement of the European Union

Directory of Open Access Journals (Sweden)

Dudas Gabor

2010-01-01

Full Text Available The liberalization of the European air opened the strictly regulated European market, and contributed to the appearance and quick spread of the Low-Cost Carriers (LCCs. At the beginning of the 21st century the low cost traffic absolutely concentrated on the Western European market but after the enlargement of the European Union (EU LCCs started their operations in Eastern Europe enlarging and enriching the former evolved network structures. The aim of this paper is to trace the evolution of the route network as a result of EU expansion. During the study we came to the conclusion that in the time period after the EU enlargement the European LCC traffic showed dynamic development, route networks widened and the number of accessible destinations doubled. Comparing the LCCs network structures we defined three main characteristics, which represents the North-South flows, the West-East routes and the mixed network structure.

Cost effective campaigning in social networks

Science.gov (United States)

Kotnis, Bhushan; Kuri, Joy

2016-05-01

Campaigners are increasingly using online social networking platforms for promoting products, ideas and information. A popular method of promoting a product or even an idea is incentivizing individuals to evangelize the idea vigorously by providing them with referral rewards in the form of discounts, cash backs, or social recognition. Due to budget constraints on scarce resources such as money and manpower, it may not be possible to provide incentives for the entire population, and hence incentives need to be allocated judiciously to appropriate individuals for ensuring the highest possible outreach size. We aim to do the same by formulating and solving an optimization problem using percolation theory. In particular, we compute the set of individuals that are provided incentives for minimizing the expected cost while ensuring a given outreach size. We also solve the problem of computing the set of individuals to be incentivized for maximizing the outreach size for given cost budget. The optimization problem turns out to be non trivial; it involves quantities that need to be computed by numerically solving a fixed point equation. Our primary contribution is, that for a fairly general cost structure, we show that the optimization problems can be solved by solving a simple linear program. We believe that our approach of using percolation theory to formulate an optimization problem is the first of its kind.

Secure and Cost-Effective Distributed Aggregation for Mobile Sensor Networks.

Science.gov (United States)

Guo, Kehua; Zhang, Ping; Ma, Jianhua

2016-04-23

Secure data aggregation (SDA) schemes are widely used in distributed applications, such as mobile sensor networks, to reduce communication cost, prolong the network life cycle and provide security. However, most SDA are only suited for a single type of statistics (i.e., summation-based or comparison-based statistics) and are not applicable to obtaining multiple statistic results. Most SDA are also inefficient for dynamic networks. This paper presents multi-functional secure data aggregation (MFSDA), in which the mapping step and coding step are introduced to provide value-preserving and order-preserving and, later, to enable arbitrary statistics support in the same query. MFSDA is suited for dynamic networks because these active nodes can be counted directly from aggregation data. The proposed scheme is tolerant to many types of attacks. The network load of the proposed scheme is balanced, and no significant bottleneck exists. The MFSDA includes two versions: MFSDA-I and MFSDA-II. The first one can obtain accurate results, while the second one is a more generalized version that can significantly reduce network traffic at the expense of less accuracy loss.

Road networks as collections of minimum cost paths

Science.gov (United States)

Wegner, Jan Dirk; Montoya-Zegarra, Javier Alexander; Schindler, Konrad

2015-10-01

We present a probabilistic representation of network structures in images. Our target application is the extraction of urban roads from aerial images. Roads appear as thin, elongated, partially curved structures forming a loopy graph, and this complex layout requires a prior that goes beyond standard smoothness and co-occurrence assumptions. In the proposed model the network is represented as a union of 1D paths connecting distant (super-)pixels. A large set of putative candidate paths is constructed in such a way that they include the true network as much as possible, by searching for minimum cost paths in the foreground (road) likelihood. Selecting the optimal subset of candidate paths is posed as MAP inference in a higher-order conditional random field. Each path forms a higher-order clique with a type of clique potential, which attracts the member nodes of cliques with high cumulative road evidence to the foreground label. That formulation induces a robust PN -Potts model, for which a global MAP solution can be found efficiently with graph cuts. Experiments with two road data sets show that the proposed model significantly improves per-pixel accuracies as well as the overall topological network quality with respect to several baselines.

Impact and Cost Evaluation of Electric Vehicle Integration on Medium Voltage Distribution Networks

DEFF Research Database (Denmark)

Wu, Qiuwei; Cheng, Lin; Pineau, Ulysse

2013-01-01

This paper presents the analysis of the impact of electric vehicle (EV) integration on medium voltage (MV) distribution networks and the cost evaluation of replacing the overloaded grid components. A number of EV charging scenarios have been studied. A 10 kV grid from the Bornholm Island...... in the city area has been used to carry out case studies. The case study results show that the secondary transformers are the bottleneck of the MV distribution networks and the increase of EV penetration leads to the overloading of secondary transformers. The cost of the transformer replacement has been...

On the Development of Methodology for Planning and Cost-Modeling of a Wide Area Network

OpenAIRE

Ahmedi, Basri; Mitrevski, Pece

2014-01-01

The most important stages in designing a computer network in a wider geographical area include: definition of requirements, topological description, identification and calculation of relevant parameters (i.e. traffic matrix), determining the shortest path between nodes, quantification of the effect of various levels of technical and technological development of urban areas involved, the cost of technology, and the cost of services. These parameters differ for WAN networks in different regions...

evaluation of total annual costs of heat exchanger networks using

African Journals Online (AJOL)

This study presents pinch analysis of some heat exchanger networks (HENs) problems using Hint integration (HINT) software. Three examples reported to have been solved using different approaches by various researchers to obtain the least possible total annual cost (TAC) were solved using the Hint software. In this work ...

NetPICOmag: A low-cost networked magnetometer and its applications

Science.gov (United States)

Schofield, I.; Connors, M.; Russell, C. T.

2012-03-01

NetPICOmag (NPM) is the culmination of a design effort to build a compact, low-cost, laboratory-grade, networked magnetometer designed for remote autonomous operation, suited for research and education. NPM allows wide placement of magnetometers sensitive enough to detect auroral activity and the daily variation, and is suitable for education projects and a range of geophysical applications. The use of networked microcontrollers and GPS timing is applicable to other small instruments for field or local deployment, and an onboard data logging capability has also been demonstrated. We illustrate the value of the placement of low-cost magnetometers to increase coverage in an area through the study of a Pc 5 pulsation event which took place on September 4, 2010. By combining results with those from auroral zone magnetometers supporting the THEMIS project, we find that the phase velocity of these morning sector pulsations was northward on the ground. The event took place under very quiet solar wind conditions, and credible mapping associates it with the inner magnetosphere. Another aspect beyond increasing areal coverage is increasing density of coverage, which becomes feasible with instruments of very low cost. We examine aspects of the April 5, 2010 space weather event which are possible to deduce from closely spaced magnetometers.

Triadic Closure in Core Networks : Disentangling the Effects of Social Distance, National Origin Similarity and Shared Contexts

NARCIS (Netherlands)

Mollenhorst, Gerald|info:eu-repo/dai/nl/304835153; Van Duijn, Marijtje; Rydgren, Jens; Edling, Christofer

2016-01-01

Acknowledging that the composition and structure of personal networks is affected by meeting opportunities, social distance, and national origin similarity, we aim to disentangle their association with triadic closure in the core of personal networks. We use data (collected 2009) on the core

Triadic closure in core networks: Disentangling the effects of social distance, natoinal origin similarity and shared contexts

NARCIS (Netherlands)

Mollenhorst, Gerald; van Duijn, Maria; Rydgren, Jens; Edling, Christopher

2016-01-01

Acknowledging that the composition and structure of personal networks is affected by meeting opportunities, social distance, and national origin similarity, we aim to disentangle their association with triadic closure in the core of personal networks. We use data (collected 2009) on the core

Measuring the Influence of Networks on Transaction Costs Using a Nonparametric Regression Technique

DEFF Research Database (Denmark)

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

All business transactions as well as achieving innovations take up resources, subsumed under the concept of transaction costs. One of the major factors in transaction costs theory is information. Firm networks can catalyse the interpersonal information exchange and hence, increase the access to non......-public information so that transaction costs are reduced.Many resources that are sacrificed for transaction costs are inputs that also enter the technical production process. As most production data do not distinguish between these two usages of inputs, high transaction costs result in reduced observed productivity...

Social grooming network in captive chimpanzees: does the wild or captive origin of group members affect sociality?

Science.gov (United States)

Levé, Marine; Sueur, Cédric; Petit, Odile; Matsuzawa, Tetsuro; Hirata, Satoshi

2016-01-01

Many chimpanzees throughout the world are housed in captivity, and there is an increasing effort to recreate social groups by mixing individuals with captive origins with those with wild origins. Captive origins may entail restricted rearing conditions during early infant life, including, for example, no maternal rearing and a limited social life. Early rearing conditions have been linked with differences in tool-use behavior between captive- and wild-born chimpanzees. If physical cognition can be impaired by non-natural rearing, what might be the consequences for social capacities? This study describes the results of network analysis based on grooming interactions in chimpanzees with wild and captive origins living in the Kumamoto Sanctuary in Kumamoto, Japan. Grooming is a complex social activity occupying up to 25% of chimpanzees' waking hours and plays a role in the emergence and maintenance of social relationships. We assessed whether the social centralities and roles of chimpanzees might be affected by their origin (captive vs wild). We found that captive- and wild-origin chimpanzees did not differ in their grooming behavior, but that theoretical removal of individuals from the network had differing impacts depending on the origin of the individual. Contrary to findings that non-natural early rearing has long-term effects on physical cognition, living in social groups seems to compensate for the negative effects of non-natural early rearing. Social network analysis (SNA) and, in particular, theoretical removal analysis, were able to highlight differences between individuals that would have been impossible to show using classical methods. The social environment of captive animals is important to their well-being, and we are only beginning to understand how SNA might help to enhance animal welfare.

Host switching in a generalist parasitoid: contrasting transient and transgenerational costs associated with novel and original host species.

Science.gov (United States)

Jones, Thomas S; Bilton, Adam R; Mak, Lorraine; Sait, Steven M

2015-01-01

Parasitoids face challenges by switching between host species that influence survival and fitness, determine their role in structuring communities, influence species invasions, and affect their importance as biocontrol agents. In the generalist parasitoid, Venturia canescens (Gravenhorst) (Hymenoptera: Ichneumonidae), we investigated the costs in encapsulation, survival, and body size on juveniles when adult parasitoids switched from their original host, Plodia interpunctella (Hübner) (Lepidotera, Pyralidae) to a novel host, Ephestia kuehniella (Zeller) (Lepidoptera, Pyralidae), over multiple generations. Switching had an initial survival cost for juvenile parasitoids in the novel host, but increased survival occurred within two generations. Conversely, mortality in the original host increased. Body size, a proxy for fecundity, also increased with the number of generations in the novel host species, reflecting adaptation or maternal effects due to the larger size of the novel host, and therefore greater resources available to the developing parasitoid. Switching to a novel host appears to have initial costs for a parasitoid, even when the novel host may be better quality, but the costs rapidly diminish. We predict that the net cost of switching to a novel host for parasitoids will be complex and will depend on the initial reduction in fitness from parasitizing a novel host versus local adaptations against parasitoids in the original host.

Dynamic network tariffs: are they the most efficient way to match peak consumption and network incremental costs?

OpenAIRE

João Tomé Saraiva; Guido Pires; João Filipe Nunes; José Nuno Fidalgo; Rui Barbosa Pinto

2016-01-01

The purpose of this paper is to present the main results of the ongoing analysis of applying dynamic network access tariffs in Portugal. For the 2015-2017 regulatory period, the Portuguese National Regulatory Authority, ERSE, required the three main Portuguese DSOs to submit, until the end of June 2016, plans for the implementation of network dynamic tariff schemes targeting Medium, High and Extra High Voltage customers, as well as the respective cost-benefit analysis. EDP Distribuição, the m...

Cost-related model for transit rates in electric power distribution networks

International Nuclear Information System (INIS)

Collstrand, F.

1994-02-01

The planned deregulation of the swedish electrical power market will require a new structure of the electrical energy rates. In this report different models of transit rates are studied. The report includes studies of literature and a proposal to a rate structure and is made specifically for Malmoe Energi AB. The differences between various methods of calculating the transfer cost are illustrated. Further, the build-up of the tariff structure and its base elements are discussed. The costs are divided on different categories of costumers and shows the cost for each customer. The new regulations should apply simultaneously to all networks, independent of the voltage level. The transit cost should be based on a number of basic elements: capital cost, operation and maintenance, losses, measuring and administration. Capital cost and operation and maintenance should be charged as power fees, the loss cost as an energy fee and the measuring and administration cost as a fixed fee. The customer bill should be split into two parts, one for the transit cost and one for the energy usage. 15 refs., 37 tabs., 6 figs

What Do Information Technology Support Services Really Cost?

Science.gov (United States)

Leach, Karen; Smallen, David

1998-01-01

A study examined the cost of information-technology support services in higher education institutions. The report describes the project's origins and work to date and reports initial results in three areas: network services, desktop repair services, and administrative information systems, looking in each case at economies of scale, outsourcing…

Temporal Dynamics of Sensorimotor Networks in Effort-Based Cost-Benefit Valuation: Early Emergence and Late Net Value Integration.

Science.gov (United States)

Harris, Alison; Lim, Seung-Lark

2016-07-06

Although physical effort can impose significant costs on decision-making, when and how effort cost information is incorporated into choice remains contested, reflecting a larger debate over the role of sensorimotor networks in specifying behavior. Serial information processing models, in which motor circuits simply implement the output of cognitive systems, hypothesize that effort cost factors into decisions relatively late, via integration with stimulus values into net (combined) value signals in dorsomedial frontal cortex (dmFC). In contrast, ethology-inspired approaches suggest a more active role for the dorsal sensorimotor stream, with effort cost signals emerging rapidly after stimulus onset. Here we investigated the time course of effort cost integration using event-related potentials in hungry human subjects while they made decisions about expending physical effort for appetitive foods. Consistent with the ethological perspective, we found that effort cost was represented from as early as 100-250 ms after stimulus onset, localized to dorsal sensorimotor regions including middle cingulate, somatosensory, and motor/premotor cortices. However, examining the same data time-locked to motor output revealed net value signals combining stimulus value and effort cost approximately -400 ms before response, originating from sensorimotor areas including dmFC, precuneus, and posterior parietal cortex. Granger causal connectivity analysis of the motor effector signal in the time leading to response showed interactions between these sensorimotor regions and ventrolateral prefrontal cortex, a structure associated with adjusting behavior-response mappings. These results suggest that rapid activation of sensorimotor regions interacts with cognitive valuation systems, producing a net value signal reflecting both physical effort and reward contingencies. Although physical effort imposes a cost on choice, when and how effort cost influences neural correlates of decision

How should fixed costs in the network be covered?

International Nuclear Information System (INIS)

1999-01-01

The report examines how tariffs that are only meant to cover costs in the transmission network should be formulated. Should the tariffs be based on power figures, such as for instance installed production capacity, or on an energy figure such as total annual energy production? Tariffs based on the producers' installed production capacity will in the long run cause the prises to rise under peak loads while tariffs based on generated energy elevate the consumer price by a small amount for all load segments. Thus, tariffs based on installed power capacity cause greater price distortion and greater socio-economic losses than energy tariffs. There are good arguments that fixed costs should mainly be paid by consumers with inelastic demand

The strategic capability of Asian network airlines to compete with low-cost carriers

OpenAIRE

Pearson, James; O'Connell, John F.; Pitfield, David; Ryley, Tim

2015-01-01

Never before have network airlines been so exposed and vulnerable to low-cost carriers (LCCs). While LCCs had 26.3% of all world seats in 2013, Southeast Asia had 57.7% and South Asia 58.4% – and these figures will only increase. There are many consequences of LCCs on network airlines, including inadequately meeting the expectations of customers, so increasing dissatisfaction, and not offering sufficient value-for-money. Clearly, it is fundamentally important for Asian network airlines to res...

Model for cost economic analysis in the maintenance of distribution networks

International Nuclear Information System (INIS)

Flores, N.; Leite, O.C.; Abe, R.Y.; Violante, R.A.

1989-01-01

A methodology for evaluating the costs from aerial distribution networks maintenance is described, aiming give a tool for the planning decisions, with the purpose to keeping the system operating in equilibrium conditions between the resources invested on the preventive and corrective maintenance. (C.G.C.)

Cost/worth assessment of reliability improvement in distribution networks by means of artificial intelligence

Energy Technology Data Exchange (ETDEWEB)

Bouhouras, Aggelos S.; Labridis, Dimitris P.; Bakirtzis, Anastasios G. [Power Systems Laboratory, Aristotle University of Thessaloniki, Dept. of Electrical and Computer Engineering, 54124 Thessaloniki (Greece)

2010-06-15

A major challenge for the power utilities today is to ensure a high level of reliability of supply to customers. Two main factors determine the feasibility of a project that improves the reliability of supply: the project cost (investment and operational) and the benefits that result from the implementation of the project. This paper examines the implementation of an Artificial Intelligence System in an urban distribution network, capable to locate and isolate short circuit faults in the feeder, thus accomplishing immediate restoration of electric supply to the customers. The paper describes the benefits of the project, which are supply reliability improvement and distribution network loss reduction through network reconfigurations. By comparison of the project benefits and costs the economic feasibility of such a project for an underground distribution feeder in Greece is demonstrated. (author)

Recruitment Strategies and Costs Associated with Community-Based Research in a Mexican-Origin Population

Science.gov (United States)

Mendez-Luck, Carolyn A.; Trejo, Laura; Miranda, Jeanne; Jimenez, Elizabeth; Quiter, Elaine S.; Mangione, Carol M.

2011-01-01

Purpose: We describe the recruitment strategies and personnel and materials costs associated with two community-based research studies in a Mexican-origin population. We also highlight the role that academic-community partnerships played in the outreach and recruitment process for our studies. We reviewed study documents using case study…

Remote Autonomous Sensor Networks: A Study in Redundancy and Life Cycle Costs

Science.gov (United States)

Ahlrichs, M.; Dotson, A.; Cenek, M.

2017-12-01

The remote nature of the United States and Canada border and their extreme seasonal shifts has made monitoring much of the area impossible using conventional monitoring techniques. Currently, the United States has large gaps in its ability to detect movement on an as-needed-basis in remote areas. The proposed autonomous sensor network aims to meet that need by developing a product that is low cost, robust, and can be deployed on an as-needed-basis for short term monitoring events. This is accomplished by identifying radio frequency disturbance and acoustic disturbance. This project aims to validate the proposed design and offer optimization strategies by conducting a redundancy model as well as performing a Life Cycle Assessment (LCA). The model will incorporate topological, meteorological, and land cover datasets to estimate sensor loss over a three-month period, ensuring that the remaining network does not have significant gaps in coverage which preclude being able to receive and transmit data. The LCA will investigate the materials used to create the sensor to generate an estimate of the total environmental energy that is utilized to create the network and offer alternative materials and distribution methods that can lower this cost. This platform can function as a stand-alone monitoring network or provide additional spatial and temporal resolution to existing monitoring networks. This study aims to create the framework to determine if a sensor's design and distribution is appropriate for the target environment. The incorporation of a LCA will seek to answer if the data a proposed sensor network will collect outweighs the environmental damage that will result from its deployment. Furthermore, as the arctic continues to thaw and economic development grows, the methodology described in paper will function as a guidance document to ensure that future sensor networks have a minimal impact on these pristine areas.

Measuring the influence of networks on transaction costs using a non-parametric regression technique

DEFF Research Database (Denmark)

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

All business transactions as well as achieving innovations take up resources, subsumed under the concept of transaction costs. One of the major factors in transaction costs theory is information. Firm networks can catalyse the interpersonal information exchange and hence, increase the access to non......-public information so that transaction costs are reduced. Many resources that are sacrificed for transaction costs are inputs that also enter the technical production process. As most production data do not distinguish between these two usages of inputs, high transaction costs result in reduced observed productivity...

A cost-effective traffic data collection system based on the iDEN mobile telecommunication network.

Science.gov (United States)

2008-10-01

This report describes a cost-effective data collection system for Caltrans 170 traffic signal : controller. The data collection system is based on TCP/IP communication over existing : low-cost mobile communication networks and Motorola iDEN1 mobile...

Reconfiguration of distribution networks to minimize loss and disruption costs using genetic algorithms

Energy Technology Data Exchange (ETDEWEB)

Cebrian, Juan Carlos; Kagan, Nelson [Department of Electrical Engineering, University of Sao Paulo, Escola Politecnica, Av. Prof. Luciano Gualberto, travessa 3 n 380 - CEP - 05508-970 - Sao Paulo (Brazil)

2010-01-15

In this paper a computational implementation of an evolutionary algorithm (EA) is shown in order to tackle the problem of reconfiguring radial distribution systems. The developed module considers power quality indices such as long duration interruptions and customer process disruptions due to voltage sags, by using the Monte Carlo simulation method. Power quality costs are modeled into the mathematical problem formulation, which are added to the cost of network losses. As for the EA codification proposed, a decimal representation is used. The EA operators, namely selection, recombination and mutation, which are considered for the reconfiguration algorithm, are herein analyzed. A number of selection procedures are analyzed, namely tournament, elitism and a mixed technique using both elitism and tournament. The recombination operator was developed by considering a chromosome structure representation that maps the network branches and system radiality, and another structure that takes into account the network topology and feasibility of network operation to exchange genetic material. The topologies regarding the initial population are randomly produced so as radial configurations are produced through the Prim and Kruskal algorithms that rapidly build minimum spanning trees. (author)

Measuring the Influence of Information Networks on Transaction Costs Using a Non-parametric Regression Technique

DEFF Research Database (Denmark)

Henningsen, Geraldine; Henningsen, Arne; Henning, Christian

2011-01-01

All business transactions as well as achieving innovations take up resources, subsumed under the concept of transaction costs (TAC). One of the major factors in TAC theory is information. Information networks can catalyse the interpersonal information exchange and hence, increase the access...... to nonpublic information. Our analysis shows that information networks have an impact on the level of TAC. Many resources that are sacrificed for TAC are inputs that also enter the technical production process. As most production data do not separate between these two usages of inputs, high transaction costs...

Design and management of networks with fixed transportation costs

OpenAIRE

Lange, Jean-Charles

2010-01-01

Reusable packages are logistic items used for the shipments of goods from a producer to its customers and which, once the goods have been consumed by the customers, are to be returned to the producer. This doctoral thesis addresses the strategic design and the operational management of large independent reverse networks for their return flows when fixed transportation costs apply. At the strategic level, we identify the economic logic by which the allocation of the customers should be made...

Thin Watts-Strogatz networks.

Science.gov (United States)

de Moura, Alessandro P S

2006-01-01

A modified version of the Watts-Strogatz (WS) network model is proposed, in which the number of shortcuts scales with the network size N as Nalpha, with alpha infinity, whereas in the original WS model, this ratio is constant. We call such networks "thin Watts-Strogatz networks." We show that even though the fraction of shortcuts becomes vanishingly small for large networks, they still cause a kind of small-world effect, in the sense that the length L of the network increases sublinearly with the size. We develop a mean-field theory for these networks, which predicts that the length scales as N1-alpha ln N for large N. We also study how a search using only local information works in thin WS networks. We find that the search performance is enhanced compared to the regular network, and we predict that the search time tau scales as N1-alpha/2. These theoretical results are tested using numerical simulations. We comment on the possible relevance of thin WS networks for the design of high-performance low-cost communication networks.

Modelling the Cost Performance of a Given Logistics Network Operating Under Regular and Irregular Conditions

NARCIS (Netherlands)

Janic, M.

2009-01-01

This paper develops an analytical model for the assessment of the cost performance of a given logistics network operating under regular and irregular (disruptive) conditions. In addition, the paper aims to carry out a sensitivity analysis of this cost with respect to changes of the most influencing

Experience with low-cost telemedicine in three different settings. Recommendations based on a proposed framework for network performance evaluation

Science.gov (United States)

Wootton, Richard; Vladzymyrskyy, Anton; Zolfo, Maria; Bonnardot, Laurent

2011-01-01

Background Telemedicine has been used for many years to support doctors in the developing world. Several networks provide services in different settings and in different ways. However, to draw conclusions about which telemedicine networks are successful requires a method of evaluating them. No general consensus or validated framework exists for this purpose. Objective To define a basic method of performance measurement that can be used to improve and compare teleconsultation networks; to employ the proposed framework in an evaluation of three existing networks; to make recommendations about the future implementation and follow-up of such networks. Methods Analysis based on the experience of three telemedicine networks (in operation for 7–10 years) that provide services to doctors in low-resource settings and which employ the same basic design. Findings Although there are many possible indicators and metrics that might be relevant, five measures for each of the three user groups appear to be sufficient for the proposed framework. In addition, from the societal perspective, information about clinical- and cost-effectiveness is also required. The proposed performance measurement framework was applied to three mature telemedicine networks. Despite their differences in terms of activity, size and objectives, their performance in certain respects is very similar. For example, the time to first reply from an expert is about 24 hours for each network. Although all three networks had systems in place to collect data from the user perspective, none of them collected information about the coordinator's time required or about ease of system usage. They had only limited information about quality and cost. Conclusion Measuring the performance of a telemedicine network is essential in understanding whether the network is working as intended and what effect it is having. Based on long-term field experience, the suggested framework is a practical tool that will permit

Experience with low-cost telemedicine in three different settings. Recommendations based on a proposed framework for network performance evaluation

Directory of Open Access Journals (Sweden)

Richard Wootton

2011-12-01

Full Text Available Telemedicine has been used for many years to support doctors in the developing world. Several networks provide services in different settings and in different ways. However, to draw conclusions about which telemedicine networks are successful requires a method of evaluating them. No general consensus or validated framework exists for this purpose.To define a basic method of performance measurement that can be used to improve and compare teleconsultation networks; to employ the proposed framework in an evaluation of three existing networks; to make recommendations about the future implementation and follow-up of such networks.Analysis based on the experience of three telemedicine networks (in operation for 7–10 years that provide services to doctors in low-resource settings and which employ the same basic design.Although there are many possible indicators and metrics that might be relevant, five measures for each of the three user groups appear to be sufficient for the proposed framework. In addition, from the societal perspective, information about clinical- and cost-effectiveness is also required. The proposed performance measurement framework was applied to three mature telemedicine networks. Despite their differences in terms of activity, size and objectives, their performance in certain respects is very similar. For example, the time to first reply from an expert is about 24 hours for each network. Although all three networks had systems in place to collect data from the user perspective, none of them collected information about the coordinator's time required or about ease of system usage. They had only limited information about quality and cost.Measuring the performance of a telemedicine network is essential in understanding whether the network is working as intended and what effect it is having. Based on long-term field experience, the suggested framework is a practical tool that will permit organisations to assess the performance of

A New European COST Network 'NORM4Building' (TU1301) for the Reuse of NORM Containing Residues in Building Materials

International Nuclear Information System (INIS)

Schroeyers, W.; Schreurs, S.

2014-01-01

The new COST action was initiated on the 1st of January 2014 and runs for four years. COST is supported by the EU RTD Framework Program. In the presentation more information on how to participate in the network will be provided. In the presentation the new approach and new initiatives of the NORM4BUILDING network, that has its first meeting here in the DEAD SEA Hotel on the 12-13/02/2014, will be introduced. The NORM4Building materials network will be an open network of researchers. An Advisory Board consisting mainly from NORM processing and construction industries and relevant associations and regulators are invited to work in collaboration with the scientists that will populate the various working groups and the management committee of the new COST action

Walking- and cycling track networks in Norwegian cities : cost-benefit analyses including health effects and external costs of road traffic : summary

Science.gov (United States)

2002-04-01

Cost- benefit analyses of walking- and cycling track net-works in three Norwegian cities are presented in this study. A project group working with a National Cycling Strategy in Norway initialised the study. Motivation for starting the study is the P...

APHiD: Hierarchical Task Placement to Enable a Tapered Fat Tree Topology for Lower Power and Cost in HPC Networks

Energy Technology Data Exchange (ETDEWEB)

Michelogiannakis, George; Ibrahim, Khaled Z.; Shalf, John; Wilke, Jeremiah J.; Knight, Samuel; Kenny, Joseph P.

2017-05-14

The power and procurement cost of bandwidth in system-wide networks has forced a steady drop in the byte/flop ratio. This trend of computation becoming faster relative to the network is expected to hold. In this paper, we explore how cost-oriented task placement enables reducing the cost of system-wide networks by enabling high performance even on tapered topologies where more bandwidth is provisioned at lower levels. We describe APHiD, an efficient hierarchical placement algorithm that uses new techniques to improve the quality of heuristic solutions and reduces the demand on high-level, expensive bandwidth in hierarchical topologies. We apply APHiD to a tapered fat-tree, demonstrating that APHiD maintains application scalability even for severely tapered network configurations. Using simulation, we show that for tapered networks APHiD improves performance by more than 50% over random placement and even 15% in some cases over costlier, state-of-the-art placement algorithms.

Appling a Novel Cost Function to Hopfield Neural Network for Defects Boundaries Detection of Wood Image

Directory of Open Access Journals (Sweden)

Qi Dawei

2010-01-01

Full Text Available A modified Hopfield neural network with a novel cost function was presented for detecting wood defects boundary in the image. Different from traditional methods, the boundary detection problem in this paper was formulated as an optimization process that sought the boundary points to minimize a cost function. An initial boundary was estimated by Canny algorithm first. The pixel gray value was described as a neuron state of Hopfield neural network. The state updated till the cost function touches the minimum value. The designed cost function ensured that few neurons were activated except the neurons corresponding to actual boundary points and ensured that the activated neurons are positioned in the points which had greatest change in gray value. The tools of Matlab were used to implement the experiment. The results show that the noises of the image are effectively removed, and our method obtains more noiseless and vivid boundary than those of the traditional methods.

The modular organization of human anatomical brain networks: Accounting for the cost of wiring

Directory of Open Access Journals (Sweden)

Richard F. Betzel

2017-02-01

Full Text Available Brain networks are expected to be modular. However, existing techniques for estimating a network’s modules make it difficult to assess the influence of organizational principles such as wiring cost reduction on the detected modules. Here we present a modification of an existing module detection algorithm that allowed us to focus on connections that are unexpected under a cost-reduction wiring rule and to identify modules from among these connections. We applied this technique to anatomical brain networks and showed that the modules we detected differ from those detected using the standard technique. We demonstrated that these novel modules are spatially distributed, exhibit unique functional fingerprints, and overlap considerably with rich clubs, giving rise to an alternative and complementary interpretation of the functional roles of specific brain regions. Finally, we demonstrated that, using the modified module detection approach, we can detect modules in a developmental dataset that track normative patterns of maturation. Collectively, these findings support the hypothesis that brain networks are composed of modules and provide additional insight into the function of those modules.

Networks and RegionalCompetitiveness: Towards a Transaction Cost Approach of Small-Scale Cooperation

Directory of Open Access Journals (Sweden)

Daniel Friel

2005-06-01

Full Text Available A preoccupation with competition often dominates the study of governance. A focus on competition often unnecessarily precludes the possibility that regional institutions can suspend competition in certain areas and facilitate cooperation among potential rivals, thereby potentially contributing to their mutual success. In many ways companies cooperating through these types of networks have a greater degree of flexibility than firms which are forced to rely solely on hierarchies or markets for solutions to their problems. In order to fully understand how such networks work, this article first parses out differences in definitions of networks in order to understand how the type of network mentioned above actually differs from other uses of this term. Then it develops a theory of governance that goes beyond hierarchies and markets by demonstrating how this type of network can lead to reductions in transaction costs. This claim is illustrated on hand from examples of alternative forms of organization in Germany and Italy.

The COST Action IC0604 "Telepathology Network in Europe" (EURO-TELEPATH).

Science.gov (United States)

García-Rojo, Marcial; Gonçalves, Luís; Blobel, Bernd

2012-01-01

The COST Action IC0604 "Telepathology Network in Europe" (EURO-TELEPATH) is a European COST Action that has been running from 2007 to 2011. COST Actions are funded by the COST (European Cooperation in the field of Scientific and Technical Research) Agency, supported by the Seventh Framework Programme for Research and Technological Development (FP7), of the European Union. EURO-TELEPATH's main objectives were evaluating and validating the common technological framework and communication standards required to access, transmit and manage digital medical records by pathologists and other medical professionals in a networked environment. The project was organized in four working groups. orking Group 1 "Business modeling in pathology" has designed main pathology processes - Frozen Study, Formalin Fixed Specimen Study, Telepathology, Cytology, and Autopsy -using Business Process Modeling Notation (BPMN). orking Group 2 "Informatics standards in pathology" has been dedicated to promoting the development and application of informatics standards in pathology, collaborating with Integrating the Healthcare Enterprise (IHE), Digital Imaging and Communications in Medicine (DICOM), Health Level Seven (HL7), and other standardization bodies. Working Group 3 "Images: Analysis, Processing, Retrieval and Management" worked on the use of virtual or digital slides that are fostering the use of image processing and analysis in pathology not only for research purposes, but also in daily practice. Working Group 4 "Technology and Automation in Pathology" was focused on studying the adequacy of current existing technical solutions, including, e.g., the quality of images obtained by slide scanners, or the efficiency of image analysis applications. Major outcome of this action are the collaboration with international health informatics standardization bodies to foster the development of standards for digital pathology, offering a new approach for workflow analysis, based in business process

Efficient extraction of drainage networks from massive, radar-based elevation models with least cost path search

Directory of Open Access Journals (Sweden)

M. Metz

2011-02-01

Full Text Available The availability of both global and regional elevation datasets acquired by modern remote sensing technologies provides an opportunity to significantly improve the accuracy of stream mapping, especially in remote, hard to reach regions. Stream extraction from digital elevation models (DEMs is based on computation of flow accumulation, a summary parameter that poses performance and accuracy challenges when applied to large, noisy DEMs generated by remote sensing technologies. Robust handling of DEM depressions is essential for reliable extraction of connected drainage networks from this type of data. The least-cost flow routing method implemented in GRASS GIS as the module r.watershed was redesigned to significantly improve its speed, functionality, and memory requirements and make it an efficient tool for stream mapping and watershed analysis from large DEMs. To evaluate its handling of large depressions, typical for remote sensing derived DEMs, three different methods were compared: traditional sink filling, impact reduction approach, and least-cost path search. The comparison was performed using the Shuttle Radar Topographic Mission (SRTM and Interferometric Synthetic Aperture Radar for Elevation (IFSARE datasets covering central Panama at 90 m and 10 m resolutions, respectively. The accuracy assessment was based on ground control points acquired by GPS and reference points digitized from Landsat imagery along segments of selected Panamanian rivers. The results demonstrate that the new implementation of the least-cost path method is significantly faster than the original version, can cope with massive datasets, and provides the most accurate results in terms of stream locations validated against reference points.

The Evolutionary Origins of Hierarchy.

Science.gov (United States)

Mengistu, Henok; Huizinga, Joost; Mouret, Jean-Baptiste; Clune, Jeff

2016-06-01

Hierarchical organization-the recursive composition of sub-modules-is ubiquitous in biological networks, including neural, metabolic, ecological, and genetic regulatory networks, and in human-made systems, such as large organizations and the Internet. To date, most research on hierarchy in networks has been limited to quantifying this property. However, an open, important question in evolutionary biology is why hierarchical organization evolves in the first place. It has recently been shown that modularity evolves because of the presence of a cost for network connections. Here we investigate whether such connection costs also tend to cause a hierarchical organization of such modules. In computational simulations, we find that networks without a connection cost do not evolve to be hierarchical, even when the task has a hierarchical structure. However, with a connection cost, networks evolve to be both modular and hierarchical, and these networks exhibit higher overall performance and evolvability (i.e. faster adaptation to new environments). Additional analyses confirm that hierarchy independently improves adaptability after controlling for modularity. Overall, our results suggest that the same force-the cost of connections-promotes the evolution of both hierarchy and modularity, and that these properties are important drivers of network performance and adaptability. In addition to shedding light on the emergence of hierarchy across the many domains in which it appears, these findings will also accelerate future research into evolving more complex, intelligent computational brains in the fields of artificial intelligence and robotics.

The Evolutionary Origins of Hierarchy

Science.gov (United States)

Huizinga, Joost; Clune, Jeff

2016-01-01

Hierarchical organization—the recursive composition of sub-modules—is ubiquitous in biological networks, including neural, metabolic, ecological, and genetic regulatory networks, and in human-made systems, such as large organizations and the Internet. To date, most research on hierarchy in networks has been limited to quantifying this property. However, an open, important question in evolutionary biology is why hierarchical organization evolves in the first place. It has recently been shown that modularity evolves because of the presence of a cost for network connections. Here we investigate whether such connection costs also tend to cause a hierarchical organization of such modules. In computational simulations, we find that networks without a connection cost do not evolve to be hierarchical, even when the task has a hierarchical structure. However, with a connection cost, networks evolve to be both modular and hierarchical, and these networks exhibit higher overall performance and evolvability (i.e. faster adaptation to new environments). Additional analyses confirm that hierarchy independently improves adaptability after controlling for modularity. Overall, our results suggest that the same force–the cost of connections–promotes the evolution of both hierarchy and modularity, and that these properties are important drivers of network performance and adaptability. In addition to shedding light on the emergence of hierarchy across the many domains in which it appears, these findings will also accelerate future research into evolving more complex, intelligent computational brains in the fields of artificial intelligence and robotics. PMID:27280881

The Evolutionary Origins of Hierarchy.

Directory of Open Access Journals (Sweden)

Henok Mengistu

2016-06-01

Full Text Available Hierarchical organization-the recursive composition of sub-modules-is ubiquitous in biological networks, including neural, metabolic, ecological, and genetic regulatory networks, and in human-made systems, such as large organizations and the Internet. To date, most research on hierarchy in networks has been limited to quantifying this property. However, an open, important question in evolutionary biology is why hierarchical organization evolves in the first place. It has recently been shown that modularity evolves because of the presence of a cost for network connections. Here we investigate whether such connection costs also tend to cause a hierarchical organization of such modules. In computational simulations, we find that networks without a connection cost do not evolve to be hierarchical, even when the task has a hierarchical structure. However, with a connection cost, networks evolve to be both modular and hierarchical, and these networks exhibit higher overall performance and evolvability (i.e. faster adaptation to new environments. Additional analyses confirm that hierarchy independently improves adaptability after controlling for modularity. Overall, our results suggest that the same force-the cost of connections-promotes the evolution of both hierarchy and modularity, and that these properties are important drivers of network performance and adaptability. In addition to shedding light on the emergence of hierarchy across the many domains in which it appears, these findings will also accelerate future research into evolving more complex, intelligent computational brains in the fields of artificial intelligence and robotics.

Potential travel cost saving in urban public-transport networks using smartphone guidance

Science.gov (United States)

2018-01-01

Public transport (PT) is a key element in most major cities around the world. With the development of smartphones, available journey planning information is becoming an integral part of the PT system. Each traveler has specific preferences when undertaking a trip, and these preferences can also be reflected on the smartphone. This paper considers transit assignment in urban public-transport networks in which the passengers receive smartphone-based information containing elements that might influence the travel decisions in relation to line loads, as well as passenger benefits, and the paper discusses the transition from the current widespread choosing approach to a personalized decision-making approach based on smartphone information. The approach associated with smartphone guidance that considers passengers’ preference on travel time, waiting time and transfer is proposed in the process of obtaining his/her preferred route from the potential travel routes generated by the Deep First Search (DFS) method. Two other approaches, based on the scenarios reflecting reality, include passengers with access to no real time information, and passengers that only have access to the arrival time at the platform are used as comparisons. For illustration, the same network proposed by Spiess and Florian is utilized on the experiments in an agent-based model. Two experiments are conducted respectively according to whether each passenger’s choosing method is consistent. As expected, the results in the first experiment showed that the travel for consistent passengers with smartphone guidance was clearly shorter and that it can reduce travel time exceeding 15% and weighted cost exceeding 20%, and the average saved time approximated 3.88 minutes per passenger. The second experiment presented that travel cost, as well as cost savings, gradually decreased by employing smartphone guidance, and the maximum cost savings accounted for 14.2% of the total weighted cost. PMID:29746528

Potential travel cost saving in urban public-transport networks using smartphone guidance.

Science.gov (United States)

Song, Cuiying; Guan, Wei; Ma, Jihui

2018-01-01

Public transport (PT) is a key element in most major cities around the world. With the development of smartphones, available journey planning information is becoming an integral part of the PT system. Each traveler has specific preferences when undertaking a trip, and these preferences can also be reflected on the smartphone. This paper considers transit assignment in urban public-transport networks in which the passengers receive smartphone-based information containing elements that might influence the travel decisions in relation to line loads, as well as passenger benefits, and the paper discusses the transition from the current widespread choosing approach to a personalized decision-making approach based on smartphone information. The approach associated with smartphone guidance that considers passengers' preference on travel time, waiting time and transfer is proposed in the process of obtaining his/her preferred route from the potential travel routes generated by the Deep First Search (DFS) method. Two other approaches, based on the scenarios reflecting reality, include passengers with access to no real time information, and passengers that only have access to the arrival time at the platform are used as comparisons. For illustration, the same network proposed by Spiess and Florian is utilized on the experiments in an agent-based model. Two experiments are conducted respectively according to whether each passenger's choosing method is consistent. As expected, the results in the first experiment showed that the travel for consistent passengers with smartphone guidance was clearly shorter and that it can reduce travel time exceeding 15% and weighted cost exceeding 20%, and the average saved time approximated 3.88 minutes per passenger. The second experiment presented that travel cost, as well as cost savings, gradually decreased by employing smartphone guidance, and the maximum cost savings accounted for 14.2% of the total weighted cost.

Global Approximations to Cost and Production Functions using Artificial Neural Networks

Directory of Open Access Journals (Sweden)

Efthymios G. Tsionas

2009-06-01

Full Text Available The estimation of cost and production functions in economics relies on standard specifications which are less than satisfactory in numerous situations. However, instead of fitting the data with a pre-specified model, Artificial Neural Networks (ANNs let the data itself serve as evidence to support the modelrs estimation of the underlying process. In this context, the proposed approach combines the strengths of economics, statistics and machine learning research and the paper proposes a global approximation to arbitrary cost and production functions, respectively, given by ANNs. Suggestions on implementation are proposed and empirical application relies on standard techniques. All relevant measures such as Returns to Scale (RTS and Total Factor Productivity (TFP may be computed routinely.

Origin of Peer Influence in Social Networks

Science.gov (United States)

Pinheiro, Flávio L.; Santos, Marta D.; Santos, Francisco C.; Pacheco, Jorge M.

2014-03-01

Social networks pervade our everyday lives: we interact, influence, and are influenced by our friends and acquaintances. With the advent of the World Wide Web, large amounts of data on social networks have become available, allowing the quantitative analysis of the distribution of information on them, including behavioral traits and fads. Recent studies of correlations among members of a social network, who exhibit the same trait, have shown that individuals influence not only their direct contacts but also friends' friends, up to a network distance extending beyond their closest peers. Here, we show how such patterns of correlations between peers emerge in networked populations. We use standard models (yet reflecting intrinsically different mechanisms) of information spreading to argue that empirically observed patterns of correlation among peers emerge naturally from a wide range of dynamics, being essentially independent of the type of information, on how it spreads, and even on the class of underlying network that interconnects individuals. Finally, we show that the sparser and clustered the network, the more far reaching the influence of each individual will be.

Effects of primary care team social networks on quality of care and costs for patients with cardiovascular disease.

Science.gov (United States)

Mundt, Marlon P; Gilchrist, Valerie J; Fleming, Michael F; Zakletskaia, Larissa I; Tuan, Wen-Jan; Beasley, John W

2015-03-01

Cardiovascular disease is the leading cause of mortality and morbidity in the United States. Primary care teams can be best suited to improve quality of care and lower costs for patients with cardiovascular disease. This study evaluates the associations between primary care team communication, interaction, and coordination (ie, social networks); quality of care; and costs for patients with cardiovascular disease. Using a sociometric survey, 155 health professionals from 31 teams at 6 primary care clinics identified with whom they interact daily about patient care. Social network analysis calculated variables of density and centralization representing team interaction structures. Three-level hierarchical modeling evaluated the link between team network density, centralization, and number of patients with a diagnosis of cardiovascular disease for controlled blood pressure and cholesterol, counts of urgent care visits, emergency department visits, hospital days, and medical care costs in the previous 12 months. Teams with dense interactions among all team members were associated with fewer hospital days (rate ratio [RR] = 0.62; 95% CI, 0.50-0.77) and lower medical care costs (-$556; 95% CI, -$781 to -$331) for patients with cardiovascular disease. Conversely, teams with interactions revolving around a few central individuals were associated with increased hospital days (RR = 1.45; 95% CI, 1.09-1.94) and greater costs ($506; 95% CI, $202-$810). Team-shared vision about goals and expectations mediated the relationship between social network structures and patient quality of care outcomes. Primary care teams that are more interconnected and less centralized and that have a shared team vision are better positioned to deliver high-quality cardiovascular disease care at a lower cost. © 2015 Annals of Family Medicine, Inc.

Implementing Virtual Private Networking for Enabling Lower Cost, More Secure Wide Area Communications at Sandia National Laboratories; TOPICAL

International Nuclear Information System (INIS)

MILLER, MARC M.; YONEK JR., GEORGE A.

2001-01-01

Virtual Private Networking is a new communications technology that promises lower cost, more secure wide area communications by leveraging public networks such as the Internet. Sandia National Laboratories has embraced the technology for interconnecting remote sites to Sandia's corporate network, and for enabling remote access users for both dial-up and broadband access

Implementation of a Low-Cost Energy and Environment Monitoring System Based on a Hybrid Wireless Sensor Network

Directory of Open Access Journals (Sweden)

Dong Sik Kim

2017-01-01

Full Text Available A low-cost hybrid wireless sensor network (WSN that utilizes the 917 MHz band Wireless Smart Utility Network (Wi-SUN and a 447 MHz band narrow bandwidth communication network is implemented for electric metering and room temperature, humidity, and CO2 gas measurements. A mesh network connection that is commonly utilized for the Internet of Things (IoT is used for the Wi-SUN under the Contiki OS, and a star connection is used for the narrow bandwidth network. Both a duty-cycling receiver algorithm and a digitally controlled temperature-compensated crystal oscillator algorithm for frequency reference are implemented at the physical layer of the receiver to accomplish low-power and low-cost wireless sensor node design. A two-level temperature-compensation approach, in which first a fixed third-order curve and then a sample-based first-order curve are applied, is proposed using a conventional AT-cut quartz crystal resonator. The developed WSN is installed in a home and provides reliable data collection with low construction complexity and power consumption.

Bridge Management Strategy Based on Extreme User Costs for Bridge Network Condition

Directory of Open Access Journals (Sweden)

Ladislaus Lwambuka

2014-01-01

Full Text Available This paper presents a practical approach for prioritization of bridge maintenance within a given bridge network. The maintenance prioritization is formulated as a multiobjective optimization problem where the simultaneous satisfaction of several conflicting objectives includes minimization of maintenance costs, maximization of bridge deck condition, and minimization of traffic disruption and associated user costs. The prevalence of user cost during maintenance period is twofold; the first case refers to the period of dry season where normally the traffic flow is diverted to alternative routes usually resurfaced to regain traffic access. The second prevalence refers to the absence of alternative routes which is often the case in the least developed countries; in this case the user cost referred to results from the waiting time while the traffic flow is put on hold awaiting accomplishment of the maintenance activity. This paper deals with the second scenario of traffic closure in the absence of alternative diversion routes which in essence results in extreme user cost. The paper shows that the multiobjective optimization approach remains valid for extreme cases of user costs in the absence of detour roads as often is the scenario in countries with extreme poor road infrastructure.

Delay and cost performance analysis of the diffie-hellman key exchange protocol in opportunistic mobile networks

Science.gov (United States)

Soelistijanto, B.; Muliadi, V.

2018-03-01

Diffie-Hellman (DH) provides an efficient key exchange system by reducing the number of cryptographic keys distributed in the network. In this method, a node broadcasts a single public key to all nodes in the network, and in turn each peer uses this key to establish a shared secret key which then can be utilized to encrypt and decrypt traffic between the peer and the given node. In this paper, we evaluate the key transfer delay and cost performance of DH in opportunistic mobile networks, a specific scenario of MANETs where complete end-to-end paths rarely exist between sources and destinations; consequently, the end-to-end delays in these networks are much greater than typical MANETs. Simulation results, driven by a random node movement model and real human mobility traces, showed that DH outperforms a typical key distribution scheme based on the RSA algorithm in terms of key transfer delay, measured by average key convergence time; however, DH performs as well as the benchmark in terms of key transfer cost, evaluated by total key (copies) forwards.

On the Problem of Attribute Selection for Software Cost Estimation: Input Backward Elimination Using Artificial Neural Networks

OpenAIRE

Papatheocharous , Efi; Andreou , Andreas S.

2010-01-01

International audience; Many parameters affect the cost evolution of software projects. In the area of software cost estimation and project management the main challenge is to understand and quantify the effect of these parameters, or 'cost drivers', on the effort expended to develop software systems. This paper aims at investigating the effect of cost attributes on software development effort using empirical databases of completed projects and building Artificial Neural Network (ANN) models ...

Forecasting Construction Cost Index based on visibility graph: A network approach

Science.gov (United States)

Zhang, Rong; Ashuri, Baabak; Shyr, Yu; Deng, Yong

2018-03-01

Engineering News-Record (ENR), a professional magazine in the field of global construction engineering, publishes Construction Cost Index (CCI) every month. Cost estimators and contractors assess projects, arrange budgets and prepare bids by forecasting CCI. However, fluctuations and uncertainties of CCI cause irrational estimations now and then. This paper aims at achieving more accurate predictions of CCI based on a network approach in which time series is firstly converted into a visibility graph and future values are forecasted relied on link prediction. According to the experimental results, the proposed method shows satisfactory performance since the error measures are acceptable. Compared with other methods, the proposed method is easier to implement and is able to forecast CCI with less errors. It is convinced that the proposed method is efficient to provide considerably accurate CCI predictions, which will make contributions to the construction engineering by assisting individuals and organizations in reducing costs and making project schedules.

Low-cost autonomous perceptron neural network inspired by quantum computation

Science.gov (United States)

Zidan, Mohammed; Abdel-Aty, Abdel-Haleem; El-Sadek, Alaa; Zanaty, E. A.; Abdel-Aty, Mahmoud

2017-11-01

Achieving low cost learning with reliable accuracy is one of the important goals to achieve intelligent machines to save time, energy and perform learning process over limited computational resources machines. In this paper, we propose an efficient algorithm for a perceptron neural network inspired by quantum computing composite from a single neuron to classify inspirable linear applications after a single training iteration O(1). The algorithm is applied over a real world data set and the results are outer performs the other state-of-the art algorithms.

A Low-Cost, Real-Time Network for Radiological Monitoring Around Nuclear Facilities

International Nuclear Information System (INIS)

Bertoldo, N A

2004-01-01

A low-cost, real-time radiological sensor network for emergency response has been developed and deployed at the Lawrence Livermore National Laboratory (LLNL). The Real-Time Radiological Area Monitoring (RTRAM) network is comprised of 16 Geiger-Mueller (GM) sensors positioned on the site perimeter to continuously monitor radiological conditions as part of LLNL's comprehensive environment/safety/health protection program. The RTRAM network sensor locations coincide with wind sector directions to provide thorough coverage of the one square mile site. These low-power sensors transmit measurement data back to a central command center (CCC) computer through the LLNL telecommunications infrastructure. Alarm conditions are identified by comparing current data to predetermined threshold parameters and are validated by comparison with plausible dispersion modeling scenarios and prevailing meteorological conditions. Emergency response personnel are notified of alarm conditions by automatic radio- and computer- based notifications. A secure intranet provides emergency response personnel with current condition assessment data that enable them to direct field response efforts remotely. This system provides a low-cost real-time radiation monitoring solution that is easily converted to incorporate both a hard-wired interior perimeter with strategically positioned wireless secondary and tertiary concentric remote locations. These wireless stations would be configured with solar voltaic panels that provide current to recharge batteries and power the sensors and radio transceivers. These platforms would supply data transmission at a range of up to 95 km from a single transceiver location. As necessary, using radio transceivers in repeater mode can extend the transmission range. The RTRAM network as it is presently configured at LLNL has proven to be a reliable system since initial deployment in August 2001 and maintains stability during inclement weather conditions. With the proposed

A Decision Processing Algorithm for CDC Location Under Minimum Cost SCM Network

Science.gov (United States)

Park, N. K.; Kim, J. Y.; Choi, W. Y.; Tian, Z. M.; Kim, D. J.

Location of CDC in the matter of network on Supply Chain is becoming on the high concern these days. Present status of methods on CDC has been mainly based on the calculation manually by the spread sheet to achieve the goal of minimum logistics cost. This study is focused on the development of new processing algorithm to overcome the limit of present methods, and examination of the propriety of this algorithm by case study. The algorithm suggested by this study is based on the principle of optimization on the directive GRAPH of SCM model and suggest the algorithm utilizing the traditionally introduced MST, shortest paths finding methods, etc. By the aftermath of this study, it helps to assess suitability of the present on-going SCM network and could be the criterion on the decision-making process for the optimal SCM network building-up for the demand prospect in the future.

Locating inefficient links in a large-scale transportation network

Science.gov (United States)

Sun, Li; Liu, Like; Xu, Zhongzhi; Jie, Yang; Wei, Dong; Wang, Pu

2015-02-01

Based on data from geographical information system (GIS) and daily commuting origin destination (OD) matrices, we estimated the distribution of traffic flow in the San Francisco road network and studied Braess's paradox in a large-scale transportation network with realistic travel demand. We measured the variation of total travel time Δ T when a road segment is closed, and found that | Δ T | follows a power-law distribution if Δ T 0. This implies that most roads have a negligible effect on the efficiency of the road network, while the failure of a few crucial links would result in severe travel delays, and closure of a few inefficient links would counter-intuitively reduce travel costs considerably. Generating three theoretical networks, we discovered that the heterogeneously distributed travel demand may be the origin of the observed power-law distributions of | Δ T | . Finally, a genetic algorithm was used to pinpoint inefficient link clusters in the road network. We found that closing specific road clusters would further improve the transportation efficiency.

Practice Innovation, Health Care Utilization and Costs in a Network of Federally Qualified Health Centers and Hospitals for Medicaid Enrollees.

Science.gov (United States)

Johnson, Tricia J; Jones, Art; Lulias, Cheryl; Perry, Anthony

2018-06-01

State Medicaid programs need cost-effective strategies to provide high-quality care that is accessible to individuals with low incomes and limited resources. Integrated delivery systems have been formed to provide care across the continuum, but creating a shared vision for improving community health can be challenging. Medical Home Network was created as a network of primary care providers and hospital systems providing care to Medicaid enrollees, guided by the principles of egalitarian governance, practice-level care coordination, real-time electronic alerts, and pay-for-performance incentives. This analysis of health care utilization and costs included 1,189,195 Medicaid enrollees. After implementation of Medical Home Network, a risk-adjusted increase of $9.07 or 4.3% per member per month was found over the 2 years of implementation compared with an increase of $17.25 or 9.3% per member per month, before accounting for the cost of care management fees and other financial incentives, for Medicaid enrollees within the same geographic area with a primary care provider outside of Medical Home Network. After accounting for care coordination fees paid to providers, the net risk-adjusted cost reduction was $11.0 million.

Multifuel multimodal network design; Projeto de redes multicombustiveis multimodal

Energy Technology Data Exchange (ETDEWEB)

Lage, Carolina; Dias, Gustavo; Bahiense, Laura; Ferreira Filho, Virgilio J.M. [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia (COPPE). Programa de Engenharia de Producao

2008-07-01

The objective of the Multi commodity Multimodal Network Project is the development of modeling tools and methodologies for the optimal sizing of production networks and multimodal distribution of multiple fuel and its incomes, considering investments and transportation costs. Given the inherently non-linear combinatory nature of the problem, the resolution of real instances by the complete model, in an exact way, becomes computationally intractable. Thus, the strategy for resolution should contain a combination of exacts and heuristics methods, that must be applied to subdivisions of the original problem. This paper deals with one of these subdivisions, tackling the problem of modeling a network of pipelines in order to drain the production of ethanol away from the producing plants. The objective consists in defining the best network topology, minimizing investment and operational costs, and attending the total demand. In order to do that, the network was considered a tree, where the nodes are the center of producing regions and the edges are the pipelines, trough where the ethanol produced by plants must be drained away. The main objective also includes the decision over the optimal diameter of each pipeline and the optimal size of the bombs, in order to minimize the pumping costs. (author)

Impact of connection density on regional cost differences for network operators in the Netherlands

International Nuclear Information System (INIS)

2009-04-01

The Dutch Office of Energy Regulation ('Energiekamer') has an obligation to investigate the extent to which the electricity and gas distribution businesses (DNOs) in the Netherlands face different structural environments that result in regional cost differences which, in turn, could justify tariff differences. On the basis of previous studies, Energiekamer has identified 'water crossings' and 'local taxes' as allowable regional differences. To account for them, Energiekamer has introduced an adjustment to the regulated revenues formula in order to guarantee a level-playing field to the Dutch DNOs. In addition to these factors, it has been claimed that connection density may have an impact on distribution costs and that, therefore, regulated revenues should be adjusted to compensate for regional differences in connection density between DNOs. However, so far, the research in this field has been unable to identify a sufficiently robust relationship between cost and connection density to support this claim. In order to address this issue, Energiekamer has asked Frontier Economics and Consentec to further investigate the relationship between connection density and distribution costs in the Netherlands. Therefore, our analysis has aimed at determining whether, and to what extent, connection density in the Netherlands is a significant driver of the costs of electricity and gas distribution networks. The following three questions are answered: (1) Is connection density a significant cost driver in electricity and gas networks in the Netherlands?; (2) If so, which functional form (e.g. U-shaped) does this relationship have in the Netherlands?; (3) Finally, based on the evidence collected, is the influence of connection density sufficiently well-determined to be considered a regional difference in the Dutch regulatory framework?

Application of an Original Wildfire Smoke Health Cost Benefits Transfer Protocol to the Western US, 2005-2015

Science.gov (United States)

Jones, Benjamin A.; Berrens, Robert P.

2017-11-01

Recent growth in the frequency and severity of US wildfires has led to more wildfire smoke and increased public exposure to harmful air pollutants. Populations exposed to wildfire smoke experience a variety of negative health impacts, imposing economic costs on society. However, few estimates of smoke health costs exist and none for the entire Western US, in particular, which experiences some of the largest and most intense wildfires in the US. The lack of cost estimates is troublesome because smoke health impacts are an important consideration of the overall costs of wildfire. To address this gap, this study provides the first time series estimates of PM2.5 smoke costs across mortality and several morbidity measures for the Western US over 2005-2015. This time period includes smoke from several megafires and includes years of record-breaking acres burned. Smoke costs are estimated using a benefits transfer protocol developed for contexts when original health data are not available. The novelty of our protocol is that it synthesizes the literature on choices faced by researchers when conducting a smoke cost benefit transfer. On average, wildfire smoke in the Western US creates 165 million in annual morbidity and mortality health costs.

SOFTCOST - DEEP SPACE NETWORK SOFTWARE COST MODEL

Science.gov (United States)

Tausworthe, R. C.

1994-01-01

The early-on estimation of required resources and a schedule for the development and maintenance of software is usually the least precise aspect of the software life cycle. However, it is desirable to make some sort of an orderly and rational attempt at estimation in order to plan and organize an implementation effort. The Software Cost Estimation Model program, SOFTCOST, was developed to provide a consistent automated resource and schedule model which is more formalized than the often used guesswork model based on experience, intuition, and luck. SOFTCOST was developed after the evaluation of a number of existing cost estimation programs indicated that there was a need for a cost estimation program with a wide range of application and adaptability to diverse kinds of software. SOFTCOST combines several software cost models found in the open literature into one comprehensive set of algorithms that compensate for nearly fifty implementation factors relative to size of the task, inherited baseline, organizational and system environment, and difficulty of the task. SOFTCOST produces mean and variance estimates of software size, implementation productivity, recommended staff level, probable duration, amount of computer resources required, and amount and cost of software documentation. Since the confidence level for a project using mean estimates is small, the user is given the opportunity to enter risk-biased values for effort, duration, and staffing, to achieve higher confidence levels. SOFTCOST then produces a PERT/CPM file with subtask efforts, durations, and precedences defined so as to produce the Work Breakdown Structure (WBS) and schedule having the asked-for overall effort and duration. The SOFTCOST program operates in an interactive environment prompting the user for all of the required input. The program builds the supporting PERT data base in a file for later report generation or revision. The PERT schedule and the WBS schedule may be printed and stored in a

Long-range planning cost model for support of future space missions by the deep space network

Science.gov (United States)

Sherif, J. S.; Remer, D. S.; Buchanan, H. R.

1990-01-01

A simple model is suggested to do long-range planning cost estimates for Deep Space Network (DSP) support of future space missions. The model estimates total DSN preparation costs and the annual distribution of these costs for long-range budgetary planning. The cost model is based on actual DSN preparation costs from four space missions: Galileo, Voyager (Uranus), Voyager (Neptune), and Magellan. The model was tested against the four projects and gave cost estimates that range from 18 percent above the actual total preparation costs of the projects to 25 percent below. The model was also compared to two other independent projects: Viking and Mariner Jupiter/Saturn (MJS later became Voyager). The model gave cost estimates that range from 2 percent (for Viking) to 10 percent (for MJS) below the actual total preparation costs of these missions.

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

Science.gov (United States)

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

2017-03-01

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

Fiber in access technologies and network convergence: an opportunity for optical integration

Science.gov (United States)

Ghiggino, Pierpaolo C.

2008-11-01

Broadband networks are among the fastest growing segment in telecom. The initial and still very significant push originated with xDSL technologies and indeed a significant amount of research and development is still occurring in this field with impressive results and allowing for a remarkable use of the installed copper infrastructure way beyond its originally planned bandwidth capabilities. However it is clear that ultimately a more suitable fiber based infrastructure will be needed in order to reduce both operational and network technology costs. Such cost reduction in inevitable as the added value to end users is only related to services and these cannot be priced outside a sensible window, whilst the related bandwidth increase is much more dramatic and its huge variability must be met with little or no cost impact by the network and its operation. Fiber in access has indeed the potential to cope with a huge bandwidth demand for many years to come as its inherent bandwidth capabilities are only just tapped by current service requirements. However the whole technology supply chain must follow in line. In particular optical technology must brace itself to cope with the required much larger deployment and greater cost effectiveness, whilst at the same time deliver performance suitable to the bandwidth increase offered in the longer term by the fiber medium. This paper looks at this issues and debates the opportunities for a new class of optical devices making use of the progress in optical integration

A dual exterior point simplex type algorithm for the minimum cost network flow problem

Directory of Open Access Journals (Sweden)

Geranis George

2009-01-01

Full Text Available A new dual simplex type algorithm for the Minimum Cost Network Flow Problem (MCNFP is presented. The proposed algorithm belongs to a special 'exterior- point simplex type' category. Similarly to the classical network dual simplex algorithm (NDSA, this algorithm starts with a dual feasible tree-solution and reduces the primal infeasibility, iteration by iteration. However, contrary to the NDSA, the new algorithm does not always maintain a dual feasible solution. Instead, the new algorithm might reach a basic point (tree-solution outside the dual feasible area (exterior point - dual infeasible tree.

A Cost-based Explanation of Gradual, Regional Internationalization of Multinationals on Social Networking Sites

DEFF Research Database (Denmark)

Pogrebnyakov, Nicolai

2017-01-01

This paper examines firm internationalization on social networking sites (SNS). It systematically examines costs faced by an internationalizing firm and how firms react to these costs according to “distance-dependent” (gradual and regional) and “distance-invariant” (born-global) explanations...... of internationalization. Data on 5827 country pages of 240 multinational firms on Facebook, the most popular SNS today, is used. Creating a foreign country-specific Facebook page is considered the SNS equivalent of opening a physical subsidiary in that country. The data show that multinationals exhibit...

The Social Origins of Networks and Diffusion.

Science.gov (United States)

Centola, Damon

2015-03-01

Recent research on social contagion has demonstrated significant effects of network topology on the dynamics of diffusion. However, network topologies are not given a priori. Rather, they are patterns of relations that emerge from individual and structural features of society, such as population composition, group heterogeneity, homophily, and social consolidation. Following Blau and Schwartz, the author develops a model of social network formation that explores how social and structural constraints on tie formation generate emergent social topologies and then explores the effectiveness of these social networks for the dynamics of social diffusion. Results show that, at one extreme, high levels of consolidation can create highly balkanized communities with poor integration of shared norms and practices. As suggested by Blau and Schwartz, reducing consolidation creates more crosscutting circles and significantly improves the dynamics of social diffusion across the population. However, the author finds that further reducing consolidation creates highly intersecting social networks that fail to support the widespread diffusion of norms and practices, indicating that successful social diffusion can depend on moderate to high levels of structural consolidation.

Perceptions of mobile network operators regarding the cost drivers of the South African mobile phone industry

Directory of Open Access Journals (Sweden)

Musenga F. Mpwanya

2016-11-01

Implications: The findings of this study should assist MNOs in their monitoring of cost drivers and in the identification of cost reduction opportunities, in order to remain effective and efficient in the industry. This study’s findings should help regulating authorities (such as the Department of Communications and the Independent Communication Authority of South Africa [ICASA] to gain insights into the cost drivers of the South African mobile phone industry from the perspective of a network operator, and thus to develop appropriate mobile phone policies.

Low-cost coherent receiver for long-reach optical access network using single-ended detection.

Science.gov (United States)

Zhang, Xuebing; Li, Zhaohui; Li, Jianping; Yu, Changyuan; Lau, Alan Pak Tao; Lu, Chao

2014-09-15

A low-cost coherent receiver using two 2×3 optical hybrids and single-ended detection is proposed for long-reach optical access network. This structure can detect the two polarization components of polarization division multiplexing (PDM) signals. Polarization de-multiplexing and signal-to-signal beat interference (SSBI) cancellation are realized by using only three photodiodes. Simulation results for 40 Gb/s PDM-OFDM transmissions indicate that the low-cost coherent receiver has 3.2 dB optical signal-to-noise ratio difference compared with the theoretical value.

Economic consequences of extra by-passes in district heating networks. Investment-, running- and maintenance costs

International Nuclear Information System (INIS)

Herbert, P.

1995-02-01

For various reasons, extra by-passes are installed in district heating networks to ensure a high flow temperature when the water circulation is insufficient. By 'extra by-pass' we here mean a connection between the distribution pipe and the return pipe. This study mainly deals with extra by-passes to prevent freezing. The estimation of the extra by-pass costs is based on the district heating rates. Our assumption is that an extra by-pass can be regarded as a substation in the district heating network, with regard to the demand for the water flow, heat and power. The reason is the difficulty to obtain available facts to estimate the real costs concerning extra by-passes. Therefore, the method can not claim that the information about the costs is exact but gives an indication of the size of them. The valves in an extra by-pass can be set more or less open. We assume that manual valves in extra by-passes are wide open. Thermostatic valves are, however, assumed to be adjusted in order to cause a very small water flow. 2 refs, 16 figs, 9 tabs, 6 appendices

Transforming Ordinary Buildings into Smart Buildings via Low-Cost, Self-Powering Wireless Sensors & Sensor Networks

Energy Technology Data Exchange (ETDEWEB)

Feng, Philip [Case Western Reserve Univ., Cleveland, OH (United States)

2017-06-09

The research objective of this project is to design and demonstrate a low-cost, compact, easy-to-deploy, maintenance-free sensor node technology, and a network of such sensors, which enable the monitoring of multiphysical parameters and can transform today’s ordinary buildings into smart buildings with environmental awareness. We develop the sensor node and network via engineering and integration of existing technologies, including high-efficiency mechanical energy harvesting, and ultralow-power integrated circuits (ICs) for sensing and wireless communication. Through integration and innovative power management via specifically designed low-power control circuits for wireless sensing applications, and tailoring energy-harvesting components to indoor applications, the target products will have smaller volume, higher efficiency, and much lower cost (in both manufacturing and maintenance) than the baseline technology. Our development and commercialization objective is to create prototypes for our target products under the CWRU-Intwine collaboration.

Routing of radioactive shipments in networks with time-varying costs and curfews

Energy Technology Data Exchange (ETDEWEB)

Bowler, L.A.; Mahmassani, H.S. [Univ. of Texas, Austin, TX (United States). Dept. of Civil Engineering

1998-09-01

This research examines routing of radioactive shipments in highway networks with time-dependent travel times and population densities. A time-dependent least-cost path (TDLCP) algorithm that uses a label-correcting approach is adapted to include curfews and waiting at nodes. A method is developed to estimate time-dependent population densities, which are required to estimate risk associated with the use of a particular highway link at a particular time. The TDLCP algorithm is implemented for example networks and used to examine policy questions related to radioactive shipments. It is observed that when only Interstate highway facilities are used to transport these materials, a shipment must go through many cities and has difficulty avoiding all of them during their rush hour periods. Decreases in risk, increased departure time flexibility, and modest increases in travel times are observed when primary and/or secondary roads are included in the network. Based on the results of the example implementation, the suitability of the TDLCP algorithm for strategic nuclear material and general radioactive material shipments is demonstrated.

Routing of radioactive shipments in networks with time-varying costs and curfews

International Nuclear Information System (INIS)

Bowler, L.A.; Mahmassani, H.S.

1998-09-01

This research examines routing of radioactive shipments in highway networks with time-dependent travel times and population densities. A time-dependent least-cost path (TDLCP) algorithm that uses a label-correcting approach is adapted to include curfews and waiting at nodes. A method is developed to estimate time-dependent population densities, which are required to estimate risk associated with the use of a particular highway link at a particular time. The TDLCP algorithm is implemented for example networks and used to examine policy questions related to radioactive shipments. It is observed that when only Interstate highway facilities are used to transport these materials, a shipment must go through many cities and has difficulty avoiding all of them during their rush hour periods. Decreases in risk, increased departure time flexibility, and modest increases in travel times are observed when primary and/or secondary roads are included in the network. Based on the results of the example implementation, the suitability of the TDLCP algorithm for strategic nuclear material and general radioactive material shipments is demonstrated

Design of a Multiobjective Reverse Logistics Network Considering the Cost and Service Level

Directory of Open Access Journals (Sweden)

Shuang Li

2012-01-01

Full Text Available Reverse logistics, which is induced by various forms of used products and materials, has received growing attention throughout this decade. In a highly competitive environment, the service level is an important criterion for reverse logistics network design. However, most previous studies about product returns only focused on the total cost of the reverse logistics and neglected the service level. To help a manufacturer of electronic products provide quality postsale repair service for their consumer, this paper proposes a multiobjective reverse logistics network optimisation model that considers the objectives of the cost, the total tardiness of the cycle time, and the coverage of customer zones. The Nondominated Sorting Genetic Algorithm II (NSGA-II is employed for solving this multiobjective optimisation model. To evaluate the performance of NSGA-II, a genetic algorithm based on weighted sum approach and Multiobjective Simulated Annealing (MOSA are also applied. The performance of these three heuristic algorithms is compared using numerical examples. The computational results show that NSGA-II outperforms MOSA and the genetic algorithm based on weighted sum approach. Furthermore, the key parameters of the model are tested, and some conclusions are drawn.

Análise comparativa dos custos de diferentes redes de distribuição de energia elétrica no contexto da arborização urbana Costs of aerial electricity conventional distribution networks, aerial compact distribution networks and underground networks in arboriculture context

Directory of Open Access Journals (Sweden)

Giuliana Del Nero Velasco

2006-08-01

Full Text Available Com o intuito de estudar as podas feitas em árvores urbanas e analisar novas técnicas possíveis de serem utilizadas para reduzir o número de podas e melhorar a convivência das espécies com a fiação elétrica, além de permitir à árvore desempenhar plenamente suas funções ecológicas, buscou-se levantar dados referentes aos três tipos principais de redes de distribuição de energia elétrica (aérea convencional, aérea compacta e subterrânea, em quatro concessionárias de energia elétrica, a fim de compilá-los em um só trabalho. Foram levantados custos de implantação das redes convencional, compacta e subterrânea, assim como custos de manutenção e de poda de árvores. O custo de implantação de rede convencional (primária e secundária variou de R$54.188,39 a R$67.571,43. O custo de implantação da rede compacta (primária e secundária foi em média R$62.215,99. Já o custo de implantação de uma rede subterrânea é, em média, de R$436.585,04. A rede compacta já é totalmente viável, principalmente por ter custo de implantação praticamente igual à rede convencional e ter custo de manutenção 80% menor. A rede subterrânea, embora com custo de implantação aproximadamente 10 vezes maior quando comparado com o custo da convencional, por ter reduzido custo de manutenção e alta confiabilidade do sistema elétrico, seu uso já pode ser viável em diversas ocasiões.In order to study the pruning carried out in urban trees and analyze new techniques that may be used to reduce pruning, improve the relationship between the species and the networks, and allow trees to fulfill their proper ecological functions, studies concerning the three main types of electric power distribution were carried out: aerial conventional distribution networks, aerial compact distribution networks and underground networks in four electric power companies. The study showed the implementation costs of the three named networks as well as

Event-Triggered Asynchronous Guaranteed Cost Control for Markov Jump Discrete-Time Neural Networks With Distributed Delay and Channel Fading.

Science.gov (United States)

Yan, Huaicheng; Zhang, Hao; Yang, Fuwen; Zhan, Xisheng; Peng, Chen

2017-08-18

This paper is concerned with the guaranteed cost control problem for a class of Markov jump discrete-time neural networks (NNs) with event-triggered mechanism, asynchronous jumping, and fading channels. The Markov jump NNs are introduced to be close to reality, where the modes of the NNs and guaranteed cost controller are determined by two mutually independent Markov chains. The asynchronous phenomenon is considered, which increases the difficulty of designing required mode-dependent controller. The event-triggered mechanism is designed by comparing the relative measurement error with the last triggered state at the process of data transmission, which is used to eliminate dispensable transmission and reduce the networked energy consumption. In addition, the signal fading is considered for the effect of signal reflection and shadow in wireless networks, which is modeled by the novel Rice fading models. Some novel sufficient conditions are obtained to guarantee that the closed-loop system reaches a specified cost value under the designed jumping state feedback control law in terms of linear matrix inequalities. Finally, some simulation results are provided to illustrate the effectiveness of the proposed method.

Origin labelling; Cost analysis for producers and consumers

NARCIS (Netherlands)

Terluin, I.J.; Benninga, J.; Berkhout, P.; Immink, V.M.; Janssens, S.R.M.; Jongeneel, R.A.; Rau, M.L.; Tacken, G.M.L.

2012-01-01

By stating the origin of a foodstuff, producers can provide consumers with information about where the food comes from. Country of origin labelling is the subject of debate from two different policy areas. One debate takes place in the framework of EU quality policy for agricultural products, the

Optimal Network-Topology Design

Science.gov (United States)

Li, Victor O. K.; Yuen, Joseph H.; Hou, Ting-Chao; Lam, Yuen Fung

1987-01-01

Candidate network designs tested for acceptability and cost. Optimal Network Topology Design computer program developed as part of study on topology design and analysis of performance of Space Station Information System (SSIS) network. Uses efficient algorithm to generate candidate network designs consisting of subsets of set of all network components, in increasing order of total costs and checks each design to see whether it forms acceptable network. Technique gives true cost-optimal network and particularly useful when network has many constraints and not too many components. Program written in PASCAL.

Monitoring groundwater: optimising networks to take account of cost effectiveness, legal requirements and enforcement realities

Science.gov (United States)

Allan, A.; Spray, C.

2013-12-01

regulator to ensure compliance with legal standards. On the other hand, it can be ruinously expensive to set up a monitoring network in remote areas and regulators must therefore balance the cost effectiveness of these networks against the chance that a court might question their fitness for purpose. This presentation will examine how regulators can balance legal standards for monitoring against the cost of developing and maintaining the requisite networks, while still producing observable improvements in water and ecosystem quality backed by legally enforceable sanctions for breaches. Reflecting the findings from the EU-funded GENESIS project, it will look at case law from around the world to assess how tribunals balance competing models, and the extent to which decisions may be revisited in the light of new scientific understanding. Finally, it will make recommendations to assist regulators in optimising their network designs for enforcement.

Entropy-based heavy tailed distribution transformation and visual analytics for monitoring massive network traffic

Science.gov (United States)

Han, Keesook J.; Hodge, Matthew; Ross, Virginia W.

2011-06-01

For monitoring network traffic, there is an enormous cost in collecting, storing, and analyzing network traffic datasets. Data mining based network traffic analysis has a growing interest in the cyber security community, but is computationally expensive for finding correlations between attributes in massive network traffic datasets. To lower the cost and reduce computational complexity, it is desirable to perform feasible statistical processing on effective reduced datasets instead of on the original full datasets. Because of the dynamic behavior of network traffic, traffic traces exhibit mixtures of heavy tailed statistical distributions or overdispersion. Heavy tailed network traffic characterization and visualization are important and essential tasks to measure network performance for the Quality of Services. However, heavy tailed distributions are limited in their ability to characterize real-time network traffic due to the difficulty of parameter estimation. The Entropy-Based Heavy Tailed Distribution Transformation (EHTDT) was developed to convert the heavy tailed distribution into a transformed distribution to find the linear approximation. The EHTDT linearization has the advantage of being amenable to characterize and aggregate overdispersion of network traffic in realtime. Results of applying the EHTDT for innovative visual analytics to real network traffic data are presented.

Measuring the Influence of Information Networks on Transaction Costs Using a Non-parametric Regression Technique

DEFF Research Database (Denmark)

Henningsen, Geraldine; Henningsen, Arne; Henning, Christian

2011-01-01

to nonpublic information. Our analysis shows that information networks have an impact on the level of TAC. Many resources that are sacrificed for TAC are inputs that also enter the technical production process. As most production data do not separate between these two usages of inputs, high transaction costs...

Leak Signature Space: An Original Representation for Robust Leak Location in Water Distribution Networks

Directory of Open Access Journals (Sweden)

Myrna V. Casillas

2015-03-01

Full Text Available In this paper, an original model-based scheme for leak location using pressure sensors in water distribution networks is introduced. The proposed approach is based on a new representation called the Leak Signature Space (LSS that associates a specific signature to each leak location being minimally affected by leak magnitude. The LSS considers a linear model approximation of the relation between pressure residuals and leaks that is projected onto a selected hyperplane. This new approach allows to infer the location of a given leak by comparing the position of its signature with other leak signatures. Moreover, two ways of improving the method’s robustness are proposed. First, by associating a domain of influence to each signature and second, through a time horizon analysis. The efficiency of the method is highlighted by means of a real network using several scenarios involving different number of sensors and considering the presence of noise in the measurements.

A medical cost estimation with fuzzy neural network of acute hepatitis patients in emergency room.

Science.gov (United States)

Kuo, R J; Cheng, W C; Lien, W C; Yang, T J

2015-10-01

Taiwan is an area where chronic hepatitis is endemic. Liver cancer is so common that it has been ranked first among cancer mortality rates since the early 1980s in Taiwan. Besides, liver cirrhosis and chronic liver diseases are the sixth or seventh in the causes of death. Therefore, as shown by the active research on hepatitis, it is not only a health threat, but also a huge medical cost for the government. The estimated total number of hepatitis B carriers in the general population aged more than 20 years old is 3,067,307. Thus, a case record review was conducted from all patients with diagnosis of acute hepatitis admitted to the Emergency Department (ED) of a well-known teaching-oriented hospital in Taipei. The cost of medical resource utilization is defined as the total medical fee. In this study, a fuzzy neural network is employed to develop the cost forecasting model. A total of 110 patients met the inclusion criteria. The computational results indicate that the FNN model can provide more accurate forecasts than the support vector regression (SVR) or artificial neural network (ANN). In addition, unlike SVR and ANN, FNN can also provide fuzzy IF-THEN rules for interpretation. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Chaos in a dynamic model of urban transportation network flow based on user equilibrium states

International Nuclear Information System (INIS)

Xu Meng; Gao Ziyou

2009-01-01

In this study, we investigate the dynamical behavior of network traffic flow. We first build a two-stage mathematical model to analyze the complex behavior of network flow, a dynamical model, which is based on the dynamical gravity model proposed by Dendrinos and Sonis [Dendrinos DS, Sonis M. Chaos and social-spatial dynamic. Berlin: Springer-Verlag; 1990] is used to estimate the number of trips. Considering the fact that the Origin-Destination (O-D) trip cost in the traffic network is hard to express as a functional form, in the second stage, the user equilibrium network assignment model was used to estimate the trip cost, which is the minimum cost of used path when user equilibrium (UE) conditions are satisfied. It is important to use UE to estimate the O-D cost, since a connection is built among link flow, path flow, and O-D flow. The dynamical model describes the variations of O-D flows over discrete time periods, such as each day and each week. It is shown that even in a system with dimensions equal to two, chaos phenomenon still exists. A 'Chaos Propagation' phenomenon is found in the given model.

Low-cost fused taper polymer optical fiber (LFT-POF) splitters for environmental and home-networking solution

Science.gov (United States)

Supian, L. S.; Ab-Rahman, Mohammad Syuhaimi; Harun, Mohd Hazwan; Gunab, Hadi; Sulaiman, Malik; Naim, Nani Fadzlina

2017-08-01

In visible optical communication over the multimode PMMA fibers, the overall cost of optical network can be reduced by deploying economical splitters for distributing the optical data signals from a point to multipoint in transmission network. The low-cost splitters shall have two main characteristics; good uniformity and high power efficiency. The most cost-effective and environmental friendly optical splitter having those characteristics have been developed. The device material is 100% purely based on the multimode step-index PMMA Polymer Optical Fiber (POF). The region which all fibers merged as single fiber is called as fused-taper POF. This ensures that all fibers are melted and fused properly. The results for uniformity and power efficiency of all splitters have been revealed by injecting red LED transmitter with 650 nm wavelength into input port while each end of output fibers measured by optical power meter. Final analysis shows our fused-taper splitter has low excess loss 0.53 dB and each of the output port has low insertion loss, which the average value is below 7 dB. In addition, the splitter has good uniformity that is 32:37:31% in which it is suitably used for demultiplexer fabrication.

Development and evaluation of an open-source, low-cost distributed sensor network for environmental monitoring applications

Science.gov (United States)

Gunawardena, N.; Pardyjak, E. R.; Stoll, R.; Khadka, A.

2018-02-01

Over the last decade there has been a proliferation of low-cost sensor networks that enable highly distributed sensor deployments in environmental applications. The technology is easily accessible and rapidly advancing due to the use of open-source microcontrollers. While this trend is extremely exciting, and the technology provides unprecedented spatial coverage, these sensors and associated microcontroller systems have not been well evaluated in the literature. Given the large number of new deployments and proposed research efforts using these technologies, it is necessary to quantify the overall instrument and microcontroller performance for specific applications. In this paper, an Arduino-based weather station system is presented in detail. These low-cost energy-budget measurement stations, or LEMS, have now been deployed for continuous measurements as part of several different field campaigns, which are described herein. The LEMS are low-cost, flexible, and simple to maintain. In addition to presenting the technical details of the LEMS, its errors are quantified in laboratory and field settings. A simple artificial neural network-based radiation-error correction scheme is also presented. Finally, challenges and possible improvements to microcontroller-based atmospheric sensing systems are discussed.

A Path-Based Gradient Projection Algorithm for the Cost-Based System Optimum Problem in Networks with Continuously Distributed Value of Time

Directory of Open Access Journals (Sweden)

Wen-Xiang Wu

2014-01-01

Full Text Available The cost-based system optimum problem in networks with continuously distributed value of time is formulated as a path-based form, which cannot be solved by the Frank-Wolfe algorithm. In light of magnitude improvement in the availability of computer memory in recent years, path-based algorithms have been regarded as a viable approach for traffic assignment problems with reasonably large network sizes. We develop a path-based gradient projection algorithm for solving the cost-based system optimum model, based on Goldstein-Levitin-Polyak method which has been successfully applied to solve standard user equilibrium and system optimum problems. The Sioux Falls network tested is used to verify the effectiveness of the algorithm.

Cost- and reliability-oriented aggregation point association in long-term evolution and passive optical network hybrid access infrastructure for smart grid neighborhood area network

Science.gov (United States)

Cheng, Xiao; Feng, Lei; Zhou, Fanqin; Wei, Lei; Yu, Peng; Li, Wenjing

2018-02-01

With the rapid development of the smart grid, the data aggregation point (AP) in the neighborhood area network (NAN) is becoming increasingly important for forwarding the information between the home area network and wide area network. Due to limited budget, it is unable to use one-single access technology to meet the ongoing requirements on AP coverage. This paper first introduces the wired and wireless hybrid access network with the integration of long-term evolution (LTE) and passive optical network (PON) system for NAN, which allows a good trade-off among cost, flexibility, and reliability. Then, based on the already existing wireless LTE network, an AP association optimization model is proposed to make the PON serve as many APs as possible, considering both the economic efficiency and network reliability. Moreover, since the features of the constraints and variables of this NP-hard problem, a hybrid intelligent optimization algorithm is proposed, which is achieved by the mixture of the genetic, ant colony and dynamic greedy algorithm. By comparing with other published methods, simulation results verify the performance of the proposed method in improving the AP coverage and the performance of the proposed algorithm in terms of convergence.

18F-FDG PET/CT in inflammation of unknown origin: a cost-effectiveness pilot-study

International Nuclear Information System (INIS)

Balink, H.; Tan, S.S.; Veeger, N.J.G.M.; Holleman, F.; Eck-Smit, B.L.F. van; Bennink, R.J.; Verberne, H.J.

2015-01-01

Patients with increased inflammatory parameters, nonspecific signs and symptoms without fever and without a diagnosis after a variety of diagnostic procedures are a diagnostic dilemma and are referred to as having inflammation of unknown origin (IUO). The objective of this pilot study was to compare the cost-effectiveness of a diagnostic work-up/strategy with and without 18 F-FDG PET/CT in patients with IUO using a published dataset as a reference. IUO patients without 18 F-FDG PET/CT (group A, 46 patients) and IUO patients referred for 18 F-FDG PET/CT (group B, 46 patients) were selected. IUO was defined as the combination of nonspecific signs and symptoms and a prolonged erythrocyte sedimentation rate (ESR), defined as ≥age/2 in men and ≥(age + 10)/2 in women (ESR in millimetres per hour and age in years), and/or C-reactive protein (CRP) ≥15 mg/l. The costs of all tests and procedures and the number of hospitalization days in each patient to reach a diagnosis were calculated using current Dutch tariffs. In group A a diagnosis was reached in 14 of the 46 patients. The mean cost per patient of all the diagnostic procedures was EUR2,051, and including the cost of hospitalization was EUR12,614. In group B a diagnosis was reached in 32 of the 46 patients. The mean cost per patient of all the diagnostic procedures was EUR1,821, significantly lower than in group A (p < 0.0002), and including the cost of hospitalization was EUR5,298. In IUO 18 F-FDG PET/CT has the potential to become a cost-effective routine imaging technique indicating the direction for further diagnostic decisions thereby allowing unnecessary, invasive and expensive diagnostic investigations to be avoided and possibly the duration of hospitalization to be reduced. However, a prospective multicentre ''bottom-up microcosting'' cost-effectiveness study is warranted before these preliminary data can be extrapolated to clinical practice. (orig.)

QOS-aware error recovery in wireless body sensor networks using adaptive network coding.

Science.gov (United States)

Razzaque, Mohammad Abdur; Javadi, Saeideh S; Coulibaly, Yahaya; Hira, Muta Tah

2014-12-29

Wireless body sensor networks (WBSNs) for healthcare and medical applications are real-time and life-critical infrastructures, which require a strict guarantee of quality of service (QoS), in terms of latency, error rate and reliability. Considering the criticality of healthcare and medical applications, WBSNs need to fulfill users/applications and the corresponding network's QoS requirements. For instance, for a real-time application to support on-time data delivery, a WBSN needs to guarantee a constrained delay at the network level. A network coding-based error recovery mechanism is an emerging mechanism that can be used in these systems to support QoS at very low energy, memory and hardware cost. However, in dynamic network environments and user requirements, the original non-adaptive version of network coding fails to support some of the network and user QoS requirements. This work explores the QoS requirements of WBSNs in both perspectives of QoS. Based on these requirements, this paper proposes an adaptive network coding-based, QoS-aware error recovery mechanism for WBSNs. It utilizes network-level and user-/application-level information to make it adaptive in both contexts. Thus, it provides improved QoS support adaptively in terms of reliability, energy efficiency and delay. Simulation results show the potential of the proposed mechanism in terms of adaptability, reliability, real-time data delivery and network lifetime compared to its counterparts.

Optical Access Networks

Science.gov (United States)

Zheng, Jun; Ansari, Nirwan

2005-06-01

Call for Papers: Optical Access Networks With the wide deployment of fiber-optic technology over the past two decades, we have witnessed a tremendous growth of bandwidth capacity in the backbone networks of today's telecommunications infrastructure. However, access networks, which cover the "last-mile" areas and serve numerous residential and small business users, have not been scaled up commensurately. The local subscriber lines for telephone and cable television are still using twisted pairs and coaxial cables. Most residential connections to the Internet are still through dial-up modems operating at a low speed on twisted pairs. As the demand for access bandwidth increases with emerging high-bandwidth applications, such as distance learning, high-definition television (HDTV), and video on demand (VoD), the last-mile access networks have become a bandwidth bottleneck in today's telecommunications infrastructure. To ease this bottleneck, it is imperative to provide sufficient bandwidth capacity in the access networks to open the bottleneck and thus present more opportunities for the provisioning of multiservices. Optical access solutions promise huge bandwidth to service providers and low-cost high-bandwidth services to end users and are therefore widely considered the technology of choice for next-generation access networks. To realize the vision of optical access networks, however, many key issues still need to be addressed, such as network architectures, signaling protocols, and implementation standards. The major challenges lie in the fact that an optical solution must be not only robust, scalable, and flexible, but also implemented at a low cost comparable to that of existing access solutions in order to increase the economic viability of many potential high-bandwidth applications. In recent years, optical access networks have been receiving tremendous attention from both academia and industry. A large number of research activities have been carried out or

Optimization of transport network in the Basin of Yangtze River with minimization of environmental emission and transport/investment costs

Directory of Open Access Journals (Sweden)

Haiping Shi

2016-08-01

Full Text Available The capacity of the ship-lock at the Three Gorges Dam has become bottleneck of waterway transport and caused serious congestion. In this article, a continual network design model is established to solve the problem with minimizing the transport cost and environmental emission as well as infrastructure construction cost. In this bi-level model, the upper model gives the schemes of ship-lock expansion or construction of pass-dam highway. The lower model assigns the containers in the multi-mode network and calculates the transport cost, environmental emission, and construction investment. The solution algorithm to the model is proposed. In the numerical study, scenario analyses are done to evaluate the schemes and determine the optimal one in the context of different traffic demands. The result shows that expanding the ship-lock is better than constructing pass-dam highway.

The origin of the criticality in meme popularity distribution on complex networks.

Science.gov (United States)

Kim, Yup; Park, Seokjong; Yook, Soon-Hyung

2016-03-24

Previous studies showed that the meme popularity distribution is described by a heavy-tailed distribution or a power-law, which is a characteristic feature of the criticality. Here, we study the origin of the criticality on non-growing and growing networks based on the competition induced criticality model. From the direct Mote Carlo simulations and the exact mapping into the position dependent biased random walk (PDBRW), we find that the meme popularity distribution satisfies a very robust power- law with exponent α = 3/2 if there is an innovation process. On the other hand, if there is no innovation, then we find that the meme popularity distribution is bounded and highly skewed for early transient time periods, while it satisfies a power-law with exponent α ≠ 3/2 for intermediate time periods. The exact mapping into PDBRW clearly shows that the balance between the creation of new memes by the innovation process and the extinction of old memes is the key factor for the criticality. We confirm that the balance for the criticality sustains for relatively small innovation rate. Therefore, the innovation processes with significantly influential memes should be the simple and fundamental processes which cause the critical distribution of the meme popularity in real social networks.

The origins and evolutionary history of human non-coding RNA regulatory networks.

Science.gov (United States)

Sherafatian, Masih; Mowla, Seyed Javad

2017-04-01

The evolutionary history and origin of the regulatory function of animal non-coding RNAs are not well understood. Lack of conservation of long non-coding RNAs and small sizes of microRNAs has been major obstacles in their phylogenetic analysis. In this study, we tried to shed more light on the evolution of ncRNA regulatory networks by changing our phylogenetic strategy to focus on the evolutionary pattern of their protein coding targets. We used available target databases of miRNAs and lncRNAs to find their protein coding targets in human. We were able to recognize evolutionary hallmarks of ncRNA targets by phylostratigraphic analysis. We found the conventional 3'-UTR and lesser known 5'-UTR targets of miRNAs to be enriched at three consecutive phylostrata. Firstly, in eukaryata phylostratum corresponding to the emergence of miRNAs, our study revealed that miRNA targets function primarily in cell cycle processes. Moreover, the same overrepresentation of the targets observed in the next two consecutive phylostrata, opisthokonta and eumetazoa, corresponded to the expansion periods of miRNAs in animals evolution. Coding sequence targets of miRNAs showed a delayed rise at opisthokonta phylostratum, compared to the 3' and 5' UTR targets of miRNAs. LncRNA regulatory network was the latest to evolve at eumetazoa.

The origin of the criticality in meme popularity distribution on complex networks

Science.gov (United States)

Kim, Yup; Park, Seokjong; Yook, Soon-Hyung

2016-03-01

Previous studies showed that the meme popularity distribution is described by a heavy-tailed distribution or a power-law, which is a characteristic feature of the criticality. Here, we study the origin of the criticality on non-growing and growing networks based on the competition induced criticality model. From the direct Mote Carlo simulations and the exact mapping into the position dependent biased random walk (PDBRW), we find that the meme popularity distribution satisfies a very robust power- law with exponent α = 3/2 if there is an innovation process. On the other hand, if there is no innovation, then we find that the meme popularity distribution is bounded and highly skewed for early transient time periods, while it satisfies a power-law with exponent α ≠ 3/2 for intermediate time periods. The exact mapping into PDBRW clearly shows that the balance between the creation of new memes by the innovation process and the extinction of old memes is the key factor for the criticality. We confirm that the balance for the criticality sustains for relatively small innovation rate. Therefore, the innovation processes with significantly influential memes should be the simple and fundamental processes which cause the critical distribution of the meme popularity in real social networks.

Network design for cylinder gas distribution

Directory of Open Access Journals (Sweden)

Tejinder Pal Singh

2015-01-01

Full Text Available Purpose: Network design of the supply chain is an important and strategic aspect of logistics management. In this paper, we address the network design problem specific to packaged gases (cylinder supply chain. We propose an integrated framework that allows for the determination of the optimal facility locations, the filling plant production capacities, the inventory at plants and hubs, and the number of packages to be routed in primary and secondary transportation. Design/methodology/approach: We formulate the problem as a mixed integer program and then develop a decomposition approach to solve it. We illustrate the proposed framework with numerical examples from real-life packaged gases supply chain. The results show that the decomposition approach is effective in solving a broad range of problem sizes. Findings: The main finding of this paper is that decomposing the network design problem into two sub-problems is very effective to tackle the real-life large scale network design problems occurring in cylinder gas distribution by optimizing strategic and tactical decisions and approximating the operational decisions. We also benchmark the results from the decomposition approach by solving the complete packaged gases network design model for smaller test cases. Originality/value: The main contribution of our work is that it integrates supply chain network design decisions without fixing the fillings plant locations with inventory and resource allocation decisions required at the plants. We also consider the transportation costs for the entire supply chain including the transhipment costs among different facilities by deciding the replenishment frequency.

Original Article

African Journals Online (AJOL)

such as artificial intelligence neural network models. These models offer an overall ..... superficial resemblance to the human brain, a structure with which most physicians ... associated issues such as mortality, quality of life or cost of treatment.

Time synchronization of a wired sensor network for structural health monitoring

International Nuclear Information System (INIS)

Ishikawa, Ken-ichiro; Mita, Akira

2008-01-01

This paper introduces a time synchronization system for wired smart sensor networks to be applied to the structural health monitoring of gigantic structures. The jitter of sensor nodes in the wired network depends on the wire length between the origin and the destination of the time synchronization signals. The proposed system can theoretically achieve the accuracy to limit the jitter of sensors within 34 ns by adjusting the timing depending on the wire length, and experimentally showed the jitter of 190 m separation to be within 25 ns. The proposed system uses local area network (LAN) cables and does not require additional cabling for synchronization. Thus the proposed synchronization system can be embedded in the sensor network with minimal cost

ORIGINAL ARTICLES Cost-effectiveness analysis for priority-setting ...

African Journals Online (AJOL)

health outcomes and wasted resources.4-5 It was found that the cost- effectiveness of South ... Priorities for Developing Countries Project was that emergency (and even some elective) ... to control air pollutants found that in South Africa the most cost- effective ..... outdoor air pollution in South Africa in 2000. S Afr Med J ...

QoS-Aware Error Recovery in Wireless Body Sensor Networks Using Adaptive Network Coding

Science.gov (United States)

Razzaque, Mohammad Abdur; Javadi, Saeideh S.; Coulibaly, Yahaya; Hira, Muta Tah

2015-01-01

Wireless body sensor networks (WBSNs) for healthcare and medical applications are real-time and life-critical infrastructures, which require a strict guarantee of quality of service (QoS), in terms of latency, error rate and reliability. Considering the criticality of healthcare and medical applications, WBSNs need to fulfill users/applications and the corresponding network's QoS requirements. For instance, for a real-time application to support on-time data delivery, a WBSN needs to guarantee a constrained delay at the network level. A network coding-based error recovery mechanism is an emerging mechanism that can be used in these systems to support QoS at very low energy, memory and hardware cost. However, in dynamic network environments and user requirements, the original non-adaptive version of network coding fails to support some of the network and user QoS requirements. This work explores the QoS requirements of WBSNs in both perspectives of QoS. Based on these requirements, this paper proposes an adaptive network coding-based, QoS-aware error recovery mechanism for WBSNs. It utilizes network-level and user-/application-level information to make it adaptive in both contexts. Thus, it provides improved QoS support adaptively in terms of reliability, energy efficiency and delay. Simulation results show the potential of the proposed mechanism in terms of adaptability, reliability, real-time data delivery and network lifetime compared to its counterparts. PMID:25551485

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....

Application of multivariate probabilistic (Bayesian) networks to substance use disorder risk stratification and cost estimation.

Science.gov (United States)

Weinstein, Lawrence; Radano, Todd A; Jack, Timothy; Kalina, Philip; Eberhardt, John S

2009-09-16

This paper explores the use of machine learning and Bayesian classification models to develop broadly applicable risk stratification models to guide disease management of health plan enrollees with substance use disorder (SUD). While the high costs and morbidities associated with SUD are understood by payers, who manage it through utilization review, acute interventions, coverage and cost limitations, and disease management, the literature shows mixed results for these modalities in improving patient outcomes and controlling cost. Our objective is to evaluate the potential of data mining methods to identify novel risk factors for chronic disease and stratification of enrollee utilization, which can be used to develop new methods for targeting disease management services to maximize benefits to both enrollees and payers. For our evaluation, we used DecisionQ machine learning algorithms to build Bayesian network models of a representative sample of data licensed from Thomson-Reuters' MarketScan consisting of 185,322 enrollees with three full-year claim records. Data sets were prepared, and a stepwise learning process was used to train a series of Bayesian belief networks (BBNs). The BBNs were validated using a 10 percent holdout set. The networks were highly predictive, with the risk-stratification BBNs producing area under the curve (AUC) for SUD positive of 0.948 (95 percent confidence interval [CI], 0.944-0.951) and 0.736 (95 percent CI, 0.721-0.752), respectively, and SUD negative of 0.951 (95 percent CI, 0.947-0.954) and 0.738 (95 percent CI, 0.727-0.750), respectively. The cost estimation models produced area under the curve ranging from 0.72 (95 percent CI, 0.708-0.731) to 0.961 (95 percent CI, 0.95-0.971). We were able to successfully model a large, heterogeneous population of commercial enrollees, applying state-of-the-art machine learning technology to develop complex and accurate multivariate models that support near-real-time scoring of novel payer

Fragmenting networks by targeting collective influencers at a mesoscopic level

Science.gov (United States)

Kobayashi, Teruyoshi; Masuda, Naoki

2016-11-01

A practical approach to protecting networks against epidemic processes such as spreading of infectious diseases, malware, and harmful viral information is to remove some influential nodes beforehand to fragment the network into small components. Because determining the optimal order to remove nodes is a computationally hard problem, various approximate algorithms have been proposed to efficiently fragment networks by sequential node removal. Morone and Makse proposed an algorithm employing the non-backtracking matrix of given networks, which outperforms various existing algorithms. In fact, many empirical networks have community structure, compromising the assumption of local tree-like structure on which the original algorithm is based. We develop an immunization algorithm by synergistically combining the Morone-Makse algorithm and coarse graining of the network in which we regard a community as a supernode. In this way, we aim to identify nodes that connect different communities at a reasonable computational cost. The proposed algorithm works more efficiently than the Morone-Makse and other algorithms on networks with community structure.

Recruitment strategies and costs associated with community-based research in a Mexican-origin population.

Science.gov (United States)

Mendez-Luck, Carolyn A; Trejo, Laura; Miranda, Jeanne; Jimenez, Elizabeth; Quiter, Elaine S; Mangione, Carol M

2011-06-01

We describe the recruitment strategies and personnel and materials costs associated with two community-based research studies in a Mexican-origin population. We also highlight the role that academic-community partnerships played in the outreach and recruitment process for our studies. We reviewed study documents using case study methodology to categorize recruitment methods, examine community partnerships, and calculate study costs. We employed several recruitment methods to identify and solicit 154 female caregivers for participation in qualitative interviews and quantitative surveys. Recruitment approaches included using flyers and word of mouth, attending health fairs, and partnering with nonprofit community-based organizations (CBOs) to sponsor targeted recruitment events. Face-to-face contact with community residents and partnerships with CBOs were most effective in enrolling caregivers into the studies. Almost 70% of participants attended a recruitment event sponsored or supported by CBOs. The least effective recruitment strategy was the use of flyers, which resulted in only 7 completed interviews or questionnaires. Time and costs related to carrying out the research varied by study, where personal interviews cost more on a per-participant basis ($1,081) than the questionnaires ($298). However, almost the same amount of time was spent in the community for both studies. Partnerships with CBOs were critical for reaching the target enrollment for our studies. The relationship between the University of California-Los Angeles (UCLA) Resource Center for Minority Aging Research/Center for Health Improvement for Minority Elderly and the Department of Aging provided the infrastructure for maintaining connections with academic-community partnerships. Nevertheless, building partnerships required time, effort, and resources for both researchers and local organizations.

Recruitment Strategies and Costs Associated With Community-Based Research in a Mexican-Origin Population

Science.gov (United States)

Mendez-Luck, Carolyn A.; Trejo, Laura; Miranda, Jeanne; Jimenez, Elizabeth; Quiter, Elaine S.; Mangione, Carol M.

2011-01-01

Purpose: We describe the recruitment strategies and personnel and materials costs associated with two community-based research studies in a Mexican-origin population. We also highlight the role that academic–community partnerships played in the outreach and recruitment process for our studies. We reviewed study documents using case study methodology to categorize recruitment methods, examine community partnerships, and calculate study costs. Results: We employed several recruitment methods to identify and solicit 154 female caregivers for participation in qualitative interviews and quantitative surveys. Recruitment approaches included using flyers and word of mouth, attending health fairs, and partnering with nonprofit community-based organizations (CBOs) to sponsor targeted recruitment events. Face-to-face contact with community residents and partnerships with CBOs were most effective in enrolling caregivers into the studies. Almost 70% of participants attended a recruitment event sponsored or supported by CBOs. The least effective recruitment strategy was the use of flyers, which resulted in only 7 completed interviews or questionnaires. Time and costs related to carrying out the research varied by study, where personal interviews cost more on a per-participant basis ($1,081) than the questionnaires ($298). However, almost the same amount of time was spent in the community for both studies. Implications: Partnerships with CBOs were critical for reaching the target enrollment for our studies. The relationship between the University of California–Los Angeles (UCLA) Resource Center for Minority Aging Research/Center for Health Improvement for Minority Elderly and the Department of Aging provided the infrastructure for maintaining connections with academic–community partnerships. Nevertheless, building partnerships required time, effort, and resources for both researchers and local organizations. PMID:21565824

Fast frequency hopping codes applied to SAC optical CDMA network

Science.gov (United States)

Tseng, Shin-Pin

2015-06-01

This study designed a fast frequency hopping (FFH) code family suitable for application in spectral-amplitude-coding (SAC) optical code-division multiple-access (CDMA) networks. The FFH code family can effectively suppress the effects of multiuser interference and had its origin in the frequency hopping code family. Additional codes were developed as secure codewords for enhancing the security of the network. In considering the system cost and flexibility, simple optical encoders/decoders using fiber Bragg gratings (FBGs) and a set of optical securers using two arrayed-waveguide grating (AWG) demultiplexers (DeMUXs) were also constructed. Based on a Gaussian approximation, expressions for evaluating the bit error rate (BER) and spectral efficiency (SE) of SAC optical CDMA networks are presented. The results indicated that the proposed SAC optical CDMA network exhibited favorable performance.

Tradeoffs between costs and greenhouse gas emissions in the design of urban transit systems

International Nuclear Information System (INIS)

Griswold, Julia B; Madanat, Samer; Horvath, Arpad

2013-01-01

Recent investments in the transit sector to address greenhouse gas emissions have concentrated on purchasing efficient replacement vehicles and inducing mode shift from the private automobile. There has been little focus on the potential of network and operational improvements, such as changes in headways, route spacing, and stop spacing, to reduce transit emissions. Most models of transit system design consider user and agency cost while ignoring emissions and the potential environmental benefit of operational improvements. We use a model to evaluate the user and agency costs as well as greenhouse gas benefit of design and operational improvements to transit systems. We examine how the operational characteristics of urban transit systems affect both costs and greenhouse gas emissions. The research identifies the Pareto frontier for designing an idealized transit network. Modes considered include bus, bus rapid transit (BRT), light rail transit (LRT), and metro (heavy) rail, with cost and emissions parameters appropriate for the United States. Passenger demand follows a many-to-many travel pattern with uniformly distributed origins and destinations. The approaches described could be used to optimize the network design of existing bus service or help to select a mode and design attributes for a new transit system. The results show that BRT provides the lowest cost but not the lowest emissions for our large city scenarios. Bus and LRT systems have low costs and the lowest emissions for our small city scenarios. Relatively large reductions in emissions from the cost-optimal system can be achieved with only minor increases in user travel time. (letter)

An approach to efficient mobility management in intelligent networks

Science.gov (United States)

Murthy, K. M. S.

1995-01-01

Providing personal communication systems supporting full mobility require intelligent networks for tracking mobile users and facilitating outgoing and incoming calls over different physical and network environments. In realizing the intelligent network functionalities, databases play a major role. Currently proposed network architectures envision using the SS7-based signaling network for linking these DB's and also for interconnecting DB's with switches. If the network has to support ubiquitous, seamless mobile services, then it has to support additionally mobile application parts, viz., mobile origination calls, mobile destination calls, mobile location updates and inter-switch handovers. These functions will generate significant amount of data and require them to be transferred between databases (HLR, VLR) and switches (MSC's) very efficiently. In the future, the users (fixed or mobile) may use and communicate with sophisticated CPE's (e.g. multimedia, multipoint and multisession calls) which may require complex signaling functions. This will generate volumness service handling data and require efficient transfer of these message between databases and switches. Consequently, the network providers would be able to add new services and capabilities to their networks incrementally, quickly and cost-effectively.

Video distribution system cost model

Science.gov (United States)

Gershkoff, I.; Haspert, J. K.; Morgenstern, B.

1980-01-01

A cost model that can be used to systematically identify the costs of procuring and operating satellite linked communications systems is described. The user defines a network configuration by specifying the location of each participating site, the interconnection requirements, and the transmission paths available for the uplink (studio to satellite), downlink (satellite to audience), and voice talkback (between audience and studio) segments of the network. The model uses this information to calculate the least expensive signal distribution path for each participating site. Cost estimates are broken downy by capital, installation, lease, operations and maintenance. The design of the model permits flexibility in specifying network and cost structure.

SOME NOTES ON COST ALLOCATION IN MULTICASTING

Directory of Open Access Journals (Sweden)

Darko Skorin-Kapov

2012-12-01

Full Text Available We analyze the cost allocation strategies with the problef of broadcasting information from some source to a number of communication network users. A multicast routing chooses a minimum cost tree network that spans the source and all the receivers. The cost of such a network is distributed among its receivers who may be individuals or organizations with possibly conflicting interests. Providing network developers, users and owners with practical computable 'fair' cost allocation solution procedures is of great importance for network mamagement. Consequently, this multidisciplinary problem was extensively studied by Operational Researchers, Economists, Mathematicians and Computer Scientists. The fairness of various proposed solutions was even argued in US courts. This presentation overviews some previously published, as well as some recent results, in the development of algorithmic mechanisms to efficiently compute 'attractive' cost allocation solutions for multicast networks. Specifically, we will analyze cooperative game theory based cost allocation models that avoid cross subsidies and/or are distance and population monotonic. We will also present some related open cost allocation problems and the potential contribution that such models might make to this problem in the future.

The impact of cost and network topology on urban mobility: a study of public bicycle usage in 2 U.S. cities.

Science.gov (United States)

Jurdak, Raja

2013-01-01

Understanding the drivers of urban mobility is vital for epidemiology, urban planning, and communication networks. Human movements have so far been studied by observing people's positions in a given space and time, though most recent models only implicitly account for expected costs and returns for movements. This paper explores the explicit impact of cost and network topology on mobility dynamics, using data from 2 city-wide public bicycle share systems in the USA. User mobility is characterized through the distribution of trip durations, while network topology is characterized through the pairwise distances between stations and the popularity of stations and routes. Despite significant differences in station density and physical layout between the 2 cities, trip durations follow remarkably similar distributions that exhibit cost sensitive trends around pricing point boundaries, particularly with long-term users of the system. Based on the results, recommendations for dynamic pricing and incentive schemes are provided to positively influence mobility patterns and guide improved planning and management of public bicycle systems to increase uptake.

Wireless Sensor Network Handles Image Data

Science.gov (United States)

2008-01-01

To relay data from remote locations for NASA s Earth sciences research, Goddard Space Flight Center contributed to the development of "microservers" (wireless sensor network nodes), which are now used commercially as a quick and affordable means to capture and distribute geographical information, including rich sets of aerial and street-level imagery. NASA began this work out of a necessity for real-time recovery of remote sensor data. These microservers work much like a wireless office network, relaying information between devices. The key difference, however, is that instead of linking workstations within one office, the interconnected microservers operate miles away from one another. This attribute traces back to the technology s original use: The microservers were originally designed for seismology on remote glaciers and ice streams in Alaska, Greenland, and Antarctica-acquiring, storing, and relaying data wirelessly between ground sensors. The microservers boast three key attributes. First, a researcher in the field can establish a "managed network" of microservers and rapidly see the data streams (recovered wirelessly) on a field computer. This rapid feedback permits the researcher to reconfigure the network for different purposes over the course of a field campaign. Second, through careful power management, the microservers can dwell unsupervised in the field for up to 2 years, collecting tremendous amounts of data at a research location. The third attribute is the exciting potential to deploy a microserver network that works in synchrony with robotic explorers (e.g., providing ground truth validation for satellites, supporting rovers as they traverse the local environment). Managed networks of remote microservers that relay data unsupervised for up to 2 years can drastically reduce the costs of field instrumentation and data rec

Supply disruption cost for power network planning

International Nuclear Information System (INIS)

Kjoelle, G.H.

1992-09-01

A description is given of the method of approach to calculate the total annual socio-economic cost of power supply disruption and non-supplied energy, included the utilities' cost for planning. The total socio-economic supply disruption cost is the sum of the customers' disruption cost and the utilities' cost for failure and disruption. The mean weighted disruption cost for Norway for one hour disruption is NOK 19 per kWh. The customers' annual disruption cost is calculated with basis in the specific disruption cost referred to heavy load (January) and dimensioning maximum loads. The loads are reduced by factors taking into account the time variations of the failure frequency, duration, the loads and the disruption cost. 6 refs

Warranty optimisation based on the prediction of costs to the manufacturer using neural network model and Monte Carlo simulation

Science.gov (United States)

Stamenkovic, Dragan D.; Popovic, Vladimir M.

2015-02-01

Warranty is a powerful marketing tool, but it always involves additional costs to the manufacturer. In order to reduce these costs and make use of warranty's marketing potential, the manufacturer needs to master the techniques for warranty cost prediction according to the reliability characteristics of the product. In this paper a combination free replacement and pro rata warranty policy is analysed as warranty model for one type of light bulbs. Since operating conditions have a great impact on product reliability, they need to be considered in such analysis. A neural network model is used to predict light bulb reliability characteristics based on the data from the tests of light bulbs in various operating conditions. Compared with a linear regression model used in the literature for similar tasks, the neural network model proved to be a more accurate method for such prediction. Reliability parameters obtained in this way are later used in Monte Carlo simulation for the prediction of times to failure needed for warranty cost calculation. The results of the analysis make possible for the manufacturer to choose the optimal warranty policy based on expected product operating conditions. In such a way, the manufacturer can lower the costs and increase the profit.

An Optical Multicast Routing with Minimal Network Coding Operations in WDM Networks

Directory of Open Access Journals (Sweden)

Huanlin Liu

2014-01-01

Full Text Available Network coding can improve the optical multicast routing performance in terms of network throughput, bandwidth utilization, and traffic load balance. But network coding needs high encoding operations costs in all-optical WDM networks due to shortage of optical RAM. In the paper, the network coding operation is defined to evaluate the number of network coding operation cost in the paper. An optical multicast routing algorithm based on minimal number of network coding operations is proposed to improve the multicast capacity. Two heuristic criteria are designed to establish the multicast routing with low network coding cost and high multicast capacity. One is to select one path from the former K shortest paths with the least probability of dropping the multicast maximal capacity. The other is to select the path with lowest potential coding operations with the highest link shared degree among the multiple wavelength disjoint paths cluster from source to each destination. Comparing with the other multicast routing based on network coding, simulation results show that the proposed multicast routing algorithm can effectively reduce the times of network coding operations, can improve the probability of reaching multicast maximal capacity, and can keep the less multicast routing link cost for optical WDM networks.

QoS-Aware Error Recovery in Wireless Body Sensor Networks Using Adaptive Network Coding

Directory of Open Access Journals (Sweden)

Mohammad Abdur Razzaque

2014-12-01

Full Text Available Wireless body sensor networks (WBSNs for healthcare and medical applications are real-time and life-critical infrastructures, which require a strict guarantee of quality of service (QoS, in terms of latency, error rate and reliability. Considering the criticality of healthcare and medical applications, WBSNs need to fulfill users/applications and the corresponding network’s QoS requirements. For instance, for a real-time application to support on-time data delivery, a WBSN needs to guarantee a constrained delay at the network level. A network coding-based error recovery mechanism is an emerging mechanism that can be used in these systems to support QoS at very low energy, memory and hardware cost. However, in dynamic network environments and user requirements, the original non-adaptive version of network coding fails to support some of the network and user QoS requirements. This work explores the QoS requirements of WBSNs in both perspectives of QoS. Based on these requirements, this paper proposes an adaptive network coding-based, QoS-aware error recovery mechanism for WBSNs. It utilizes network-level and user-/application-level information to make it adaptive in both contexts. Thus, it provides improved QoS support adaptively in terms of reliability, energy efficiency and delay. Simulation results show the potential of the proposed mechanism in terms of adaptability, reliability, real-time data delivery and network lifetime compared to its counterparts.

Wood heat networks - Scope of relevancy

International Nuclear Information System (INIS)

Baiz, Adam; Monnoyer-Smith, Laurence

2017-01-01

As the French law of energy transition for a green growth foresees a strong development of heat networks based on renewable energies, this study aims at proposing elements of answer about wood-based heat networks: can they be competitive with respect to cheap gas? Would high power networks result in important economies of scale? Which will be the impact of a reduction of energy consumption in a renewed area on the profitability of a heat network? A model of actor-based and social-economic costs has been developed to compare the profitability of wood-supplied heat networks with that of conventional heating means (individual electric heating, individual or collective gas heating, heat pump, individual fuel heating, and individual wood heating). The model makes the distinction between investment fixed costs, varying energy consumption and exploitation costs, and also externalised environmental costs. Then, different scale effects are assessed. They may concern investment costs for boiler, for sub-stations and for the distribution network. The cost interval of heat networks is then studied among the very heterogeneous existing heat networks. Investment and production costs of different configurations of the different above-mentioned heat networks are discussed

Behavioral and network origins of wealth inequality: insights from a virtual world.

Directory of Open Access Journals (Sweden)

Benedikt Fuchs

Full Text Available Almost universally, wealth is not distributed uniformly within societies or economies. Even though wealth data have been collected in various forms for centuries, the origins for the observed wealth-disparity and social inequality are not yet fully understood. Especially the impact and connections of human behavior on wealth could so far not be inferred from data. Here we study wealth data from the virtual economy of the massive multiplayer online game (MMOG Pardus. This data not only contains every player's wealth at every point in time, but also all actions over a timespan of almost a decade. We find that wealth distributions in the virtual world are very similar to those in Western countries. In particular we find an approximate exponential distribution for low wealth levels and a power-law tail for high levels. The Gini index is found to be g = 0.65, which is close to the indices of many Western countries. We find that wealth-increase rates depend on the time when players entered the game. Players that entered the game early on tend to have remarkably higher wealth-increase rates than those who joined later. Studying the players' positions within their social networks, we find that the local position in the trade network is most relevant for wealth. Wealthy people have high in- and out-degrees in the trade network, relatively low nearest-neighbor degrees, and low clustering coefficients. Wealthy players have many mutual friendships and are socially well respected by others, but spend more time on business than on socializing. Wealthy players have few personal enemies, but show animosity towards players that behave as public enemies. We find that players that are not organized within social groups are significantly poorer on average. We observe that "political" status and wealth go hand in hand.

Behavioral and network origins of wealth inequality: insights from a virtual world.

Science.gov (United States)

Fuchs, Benedikt; Thurner, Stefan

2014-01-01

Almost universally, wealth is not distributed uniformly within societies or economies. Even though wealth data have been collected in various forms for centuries, the origins for the observed wealth-disparity and social inequality are not yet fully understood. Especially the impact and connections of human behavior on wealth could so far not be inferred from data. Here we study wealth data from the virtual economy of the massive multiplayer online game (MMOG) Pardus. This data not only contains every player's wealth at every point in time, but also all actions over a timespan of almost a decade. We find that wealth distributions in the virtual world are very similar to those in Western countries. In particular we find an approximate exponential distribution for low wealth levels and a power-law tail for high levels. The Gini index is found to be g = 0.65, which is close to the indices of many Western countries. We find that wealth-increase rates depend on the time when players entered the game. Players that entered the game early on tend to have remarkably higher wealth-increase rates than those who joined later. Studying the players' positions within their social networks, we find that the local position in the trade network is most relevant for wealth. Wealthy people have high in- and out-degrees in the trade network, relatively low nearest-neighbor degrees, and low clustering coefficients. Wealthy players have many mutual friendships and are socially well respected by others, but spend more time on business than on socializing. Wealthy players have few personal enemies, but show animosity towards players that behave as public enemies. We find that players that are not organized within social groups are significantly poorer on average. We observe that "political" status and wealth go hand in hand.

Network cost in transmission and distribution of electric power; Naetkostnader i oeverfoering och distribution av el

Energy Technology Data Exchange (ETDEWEB)

Lindahl, A; Naeslund, B; Oettinger-Biberg, C; Olander, H; Wuolikainen, T; Fritz, P

1994-12-31

This report is divided in two parts, where part 1 treats the charges on the regional nets with special emphasis on the net owners tariffs on a deregulated market. Part 2 describes the development of the network costs in electric power distribution for the period 1991-1993. 11 figs, 33 tabs

Complete Neuron-Astrocyte Interaction Model: Digital Multiplierless Design and Networking Mechanism.

Science.gov (United States)

Haghiri, Saeed; Ahmadi, Arash; Saif, Mehrdad

2017-02-01

Glial cells, also known as neuroglia or glia, are non-neuronal cells providing support and protection for neurons in the central nervous system (CNS). They also act as supportive cells in the brain. Among a variety of glial cells, the star-shaped glial cells, i.e., astrocytes, are the largest cell population in the brain. The important role of astrocyte such as neuronal synchronization, synaptic information regulation, feedback to neural activity and extracellular regulation make the astrocytes play a vital role in brain disease. This paper presents a modified complete neuron-astrocyte interaction model that is more suitable for efficient and large scale biological neural network realization on digital platforms. Simulation results show that the modified complete interaction model can reproduce biological-like behavior of the original neuron-astrocyte mechanism. The modified interaction model is investigated in terms of digital realization feasibility and cost targeting a low cost hardware implementation. Networking behavior of this interaction is investigated and compared between two cases: i) the neuron spiking mechanism without astrocyte effects, and ii) the effect of astrocyte in regulating the neurons behavior and synaptic transmission via controlling the LTP and LTD processes. Hardware implementation on FPGA shows that the modified model mimics the main mechanism of neuron-astrocyte communication with higher performance and considerably lower hardware overhead cost compared with the original interaction model.

Online Learning Algorithm for Time Series Forecasting Suitable for Low Cost Wireless Sensor Networks Nodes

Directory of Open Access Journals (Sweden)

Juan Pardo

2015-04-01

Full Text Available Time series forecasting is an important predictive methodology which can be applied to a wide range of problems. Particularly, forecasting the indoor temperature permits an improved utilization of the HVAC (Heating, Ventilating and Air Conditioning systems in a home and thus a better energy efficiency. With such purpose the paper describes how to implement an Artificial Neural Network (ANN algorithm in a low cost system-on-chip to develop an autonomous intelligent wireless sensor network. The present paper uses a Wireless Sensor Networks (WSN to monitor and forecast the indoor temperature in a smart home, based on low resources and cost microcontroller technology as the 8051MCU. An on-line learning approach, based on Back-Propagation (BP algorithm for ANNs, has been developed for real-time time series learning. It performs the model training with every new data that arrive to the system, without saving enormous quantities of data to create a historical database as usual, i.e., without previous knowledge. Consequently to validate the approach a simulation study through a Bayesian baseline model have been tested in order to compare with a database of a real application aiming to see the performance and accuracy. The core of the paper is a new algorithm, based on the BP one, which has been described in detail, and the challenge was how to implement a computational demanding algorithm in a simple architecture with very few hardware resources.

Online Learning Algorithm for Time Series Forecasting Suitable for Low Cost Wireless Sensor Networks Nodes

Science.gov (United States)

Pardo, Juan; Zamora-Martínez, Francisco; Botella-Rocamora, Paloma

2015-01-01

Time series forecasting is an important predictive methodology which can be applied to a wide range of problems. Particularly, forecasting the indoor temperature permits an improved utilization of the HVAC (Heating, Ventilating and Air Conditioning) systems in a home and thus a better energy efficiency. With such purpose the paper describes how to implement an Artificial Neural Network (ANN) algorithm in a low cost system-on-chip to develop an autonomous intelligent wireless sensor network. The present paper uses a Wireless Sensor Networks (WSN) to monitor and forecast the indoor temperature in a smart home, based on low resources and cost microcontroller technology as the 8051MCU. An on-line learning approach, based on Back-Propagation (BP) algorithm for ANNs, has been developed for real-time time series learning. It performs the model training with every new data that arrive to the system, without saving enormous quantities of data to create a historical database as usual, i.e., without previous knowledge. Consequently to validate the approach a simulation study through a Bayesian baseline model have been tested in order to compare with a database of a real application aiming to see the performance and accuracy. The core of the paper is a new algorithm, based on the BP one, which has been described in detail, and the challenge was how to implement a computational demanding algorithm in a simple architecture with very few hardware resources. PMID:25905698

Online learning algorithm for time series forecasting suitable for low cost wireless sensor networks nodes.

Science.gov (United States)

Pardo, Juan; Zamora-Martínez, Francisco; Botella-Rocamora, Paloma

2015-04-21

Time series forecasting is an important predictive methodology which can be applied to a wide range of problems. Particularly, forecasting the indoor temperature permits an improved utilization of the HVAC (Heating, Ventilating and Air Conditioning) systems in a home and thus a better energy efficiency. With such purpose the paper describes how to implement an Artificial Neural Network (ANN) algorithm in a low cost system-on-chip to develop an autonomous intelligent wireless sensor network. The present paper uses a Wireless Sensor Networks (WSN) to monitor and forecast the indoor temperature in a smart home, based on low resources and cost microcontroller technology as the 8051MCU. An on-line learning approach, based on Back-Propagation (BP) algorithm for ANNs, has been developed for real-time time series learning. It performs the model training with every new data that arrive to the system, without saving enormous quantities of data to create a historical database as usual, i.e., without previous knowledge. Consequently to validate the approach a simulation study through a Bayesian baseline model have been tested in order to compare with a database of a real application aiming to see the performance and accuracy. The core of the paper is a new algorithm, based on the BP one, which has been described in detail, and the challenge was how to implement a computational demanding algorithm in a simple architecture with very few hardware resources.

Managing Ongoing EVSE Costs

Energy Technology Data Exchange (ETDEWEB)

Hodge, Cabell [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

2017-09-05

The costs associated with EVSE begin with picking the best location and unit for the job, but they continue with electricity and network charges through the life of your vehicle. This presentation tells how to balance electricity demand charges and network management costs through smart planning at your program's inception.

The origins of originality: the neural bases of creative thinking and originality.

Science.gov (United States)

Shamay-Tsoory, S G; Adler, N; Aharon-Peretz, J; Perry, D; Mayseless, N

2011-01-01

Although creativity has been related to prefrontal activity, recent neurological case studies postulate that patients who have left frontal and temporal degeneration involving deterioration of language abilities may actually develop de novo artistic abilities. In this study, we propose a neural and cognitive model according to which a balance between the two hemispheres affects a major aspect of creative cognition, namely, originality. In order to examine the neural basis of originality, that is, the ability to produce statistically infrequent ideas, patients with localized lesions in the medial prefrontal cortex (mPFC), inferior frontal gyrus (IFG), and posterior parietal and temporal cortex (PC), were assessed by two tasks involving divergent thinking and originality. Results indicate that lesions in the mPFC involved the most profound impairment in originality. Furthermore, precise anatomical mapping of lesions indicated that while the extent of lesion in the right mPFC was associated with impaired originality, lesions in the left PC were associated with somewhat elevated levels of originality. A positive correlation between creativity scores and left PC lesions indicated that the larger the lesion is in this area the greater the originality. On the other hand, a negative correlation was observed between originality scores and lesions in the right mPFC. It is concluded that the right mPFC is part of a right fronto-parietal network which is responsible for producing original ideas. It is possible that more linear cognitive processing such as language, mediated by left hemisphere structures interferes with creative cognition. Therefore, lesions in the left hemisphere may be associated with elevated levels of originality. Copyright © 2010 Elsevier Ltd. All rights reserved.

{sup 18}F-FDG PET/CT in inflammation of unknown origin: a cost-effectiveness pilot-study

Energy Technology Data Exchange (ETDEWEB)

Balink, H. [Medical Center Leeuwarden, Department of Nuclear Medicine, Leeuwarden (Netherlands); Tan, S.S. [Institute for Medical Technology Assessment, Erasmus University Rotterdam, Rotterdam (Netherlands); Veeger, N.J.G.M. [University Medical Center Groningen, Department of Epidemiology, Groningen (Netherlands); Holleman, F. [Academic Medical Center Amsterdam, Department of Internal Medicine, Amsterdam (Netherlands); Eck-Smit, B.L.F. van; Bennink, R.J.; Verberne, H.J. [Academic Medical Center, Department of Nuclear Medicine, Amsterdam (Netherlands)

2015-08-15

Patients with increased inflammatory parameters, nonspecific signs and symptoms without fever and without a diagnosis after a variety of diagnostic procedures are a diagnostic dilemma and are referred to as having inflammation of unknown origin (IUO). The objective of this pilot study was to compare the cost-effectiveness of a diagnostic work-up/strategy with and without {sup 18}F-FDG PET/CT in patients with IUO using a published dataset as a reference. IUO patients without {sup 18}F-FDG PET/CT (group A, 46 patients) and IUO patients referred for {sup 18}F-FDG PET/CT (group B, 46 patients) were selected. IUO was defined as the combination of nonspecific signs and symptoms and a prolonged erythrocyte sedimentation rate (ESR), defined as ≥age/2 in men and ≥(age + 10)/2 in women (ESR in millimetres per hour and age in years), and/or C-reactive protein (CRP) ≥15 mg/l. The costs of all tests and procedures and the number of hospitalization days in each patient to reach a diagnosis were calculated using current Dutch tariffs. In group A a diagnosis was reached in 14 of the 46 patients. The mean cost per patient of all the diagnostic procedures was EUR2,051, and including the cost of hospitalization was EUR12,614. In group B a diagnosis was reached in 32 of the 46 patients. The mean cost per patient of all the diagnostic procedures was EUR1,821, significantly lower than in group A (p < 0.0002), and including the cost of hospitalization was EUR5,298. In IUO {sup 18}F-FDG PET/CT has the potential to become a cost-effective routine imaging technique indicating the direction for further diagnostic decisions thereby allowing unnecessary, invasive and expensive diagnostic investigations to be avoided and possibly the duration of hospitalization to be reduced. However, a prospective multicentre ''bottom-up microcosting'' cost-effectiveness study is warranted before these preliminary data can be extrapolated to clinical practice. (orig.)

COST Action ES1401 TIDES: a European network on TIme DEpendent Seismology

Science.gov (United States)

Morelli, Andrea

2016-04-01

Using the full-length records of seismic events and background ambient noise, today seismology is going beyond still-life snapshots of the interior of the Earth, and look into time-dependent changes of its properties. Data availability has grown dramatically with the expansion of seismographic networks and data centers, so as to enable much more detailed and accurate analyses. COST Action ES1401 TIDES (TIme DEpendent Seismology; http://tides-cost.eu) aims at structuring the EU seismological community to enable development of data-intensive, time-dependent techniques for monitoring Earth active processes (e.g., earthquakes, volcanic eruptions, landslides, glacial earthquakes) as well as oil/gas reservoirs. The main structure of TIDES is organised around working groups on: Workflow integration of data and computing resources; Seismic interferometry and ambient noise; Forward problems and High-performance computing applications; Seismic tomography, full waveform inversion and uncertainties; Applications in the natural environment and industry. TIDES is an open network of European laboratories with complementary skills, and is organising a series of events - workshops and advanced training schools - as well as supporting short-duration scientific stays. The first advanced training school was held in Bertinoro (Italy) on June 2015, with attendance of about 100 participants from 20 European countries, was devoted to how to manage and model seismic data with modern tools. The next school, devoted to ambient noise, will be held in 2016 Portugal: the program will be announced at the time of this conference. TIDES will strengthen Europe's role in a critical field for natural hazards and natural resource management.

A Network Traffic Control Enhancement Approach over Bluetooth Networks

DEFF Research Database (Denmark)

Son, L.T.; Schiøler, Henrik; Madsen, Ole Brun

2003-01-01

This paper analyzes network traffic control issues in Bluetooth data networks as convex optimization problem. We formulate the problem of maximizing of total network flows and minimizing the costs of flows. An adaptive distributed network traffic control scheme is proposed as an approximated solu...... as capacity limitations and flow requirements in the network. Simulation shows that the performance of Bluetooth networks could be improved by applying the adaptive distributed network traffic control scheme...... solution of the stated optimization problem that satisfies quality of service requirements and topologically induced constraints in Bluetooth networks, such as link capacity and node resource limitations. The proposed scheme is decentralized and complies with frequent changes of topology as well......This paper analyzes network traffic control issues in Bluetooth data networks as convex optimization problem. We formulate the problem of maximizing of total network flows and minimizing the costs of flows. An adaptive distributed network traffic control scheme is proposed as an approximated...

Origin of how steam rockets can reduce space transport cost by orders of magnitude

International Nuclear Information System (INIS)

Zuppero, A.; Larson, T.K.; Schnitzler, B.G.; Rice, J.W.; Hill, T.J.; Richins, W.D.; Parlier, L.; Werner, J.E.

1999-01-01

A brief sketch shows the origin of why and how thermal rocket propulsion has the unique potential to dramatically reduce the cost of space transportation for most inner solar system missions of interest. Orders of magnitude reduction in cost are apparently possible when compared to all processes requiring electrolysis for the production of rocket fuels or propellants and to all electric propulsion systems. An order of magnitude advantage can be attributed to rocket propellant tank factors associated with storing water propellant, compared to cryogenic liquids. An order of magnitude can also be attributed to the simplicity of the extraction and processing of ice on the lunar surface, into an easily stored, non-cryogenic rocket propellant (water). A nuclear heated thermal rocket can deliver thousands of times its mass to Low Earth Orbit from the Lunar surface, providing the equivalent to orders of magnitude drop in launch cost for mass in Earth orbit. Mass includes water ice. These cost reductions depend (exponentially) on the mission delta-v requirements being less than about 6 km/s, or about 3 times the specific velocity of steam rockets (2 km/s, from Isp 200 sec). Such missions include: from the lunar surface to Low Lunar Orbit, (LLO), from LLO to lunar escape, from Low Earth Orbit (LEO) to Geosynchronous Orbit (GEO), from LEO to Earth Escape, from LEO to Mars Transfer Orbit, from LLO to GEO, missions returning payloads from about 10% of the periodic comets using propulsive capture to orbits around Earth itself, and fast, 100 day missions from Lunar Escape to Mars. All the assertions depend entirely and completely on the existence of abundant, nearly pure ice at the permanently dark North and South Poles of the Moon. copyright 1999 American Institute of Physics

Blending Hydrogen into Natural Gas Pipeline Networks: A Review of Key Issues

Energy Technology Data Exchange (ETDEWEB)

Melaina, M. W.; Antonia, O.; Penev, M.

2013-03-01

The United States has 11 distinct natural gas pipeline corridors: five originate in the Southwest, four deliver natural gas from Canada, and two extend from the Rocky Mountain region. This study assesses the potential to deliver hydrogen through the existing natural gas pipeline network as a hydrogen and natural gas mixture to defray the cost of building dedicated hydrogen pipelines.

Design of a monitoring network over France in case of a radiological accidental release

Science.gov (United States)

Abida, Rachid; Bocquet, Marc; Vercauteren, Nikki; Isnard, Olivier

The Institute of Radiation Protection and Nuclear Safety (France) is planning the set-up of an automatic nuclear aerosol monitoring network over the French territory. Each of the stations will be able to automatically sample the air aerosol content and provide activity concentration measurements on several radionuclides. This should help monitor the French and neighbouring countries nuclear power plants set. It would help evaluate the impact of a radiological incident occurring at one of these nuclear facilities. This paper is devoted to the spatial design of such a network. Here, any potential network is judged on its ability to extrapolate activity concentrations measured on the network stations over the whole domain. The performance of a network is quantitatively assessed through a cost function that measures the discrepancy between the extrapolation and the true concentration fields. These true fields are obtained through the computation of a database of dispersion accidents over one year of meteorology and originating from 20 French nuclear sites. A close to optimal network is then looked for using a simulated annealing optimisation. The results emphasise the importance of the cost function in the design of a network aimed at monitoring an accidental dispersion. Several choices of norm used in the cost function are studied and give way to different designs. The influence of the number of stations is discussed. A comparison with a purely geometric approach which does not involve simulations with a chemistry-transport model is performed.

Analyzing Multimode Wireless Sensor Networks Using the Network Calculus

Directory of Open Access Journals (Sweden)

Xi Jin

2015-01-01

Full Text Available The network calculus is a powerful tool to analyze the performance of wireless sensor networks. But the original network calculus can only model the single-mode wireless sensor network. In this paper, we combine the original network calculus with the multimode model to analyze the maximum delay bound of the flow of interest in the multimode wireless sensor network. There are two combined methods A-MM and N-MM. The method A-MM models the whole network as a multimode component, and the method N-MM models each node as a multimode component. We prove that the maximum delay bound computed by the method A-MM is tighter than or equal to that computed by the method N-MM. Experiments show that our proposed methods can significantly decrease the analytical delay bound comparing with the separate flow analysis method. For the large-scale wireless sensor network with 32 thousands of sensor nodes, our proposed methods can decrease about 70% of the analytical delay bound.

The multi-layer network nature of systemic risk and its implications for the costs of financial crises

NARCIS (Netherlands)

Poledna, S.; Molina-Borboa, J.L.; Martínez-Jaramillo, S.; van der Leij, M.; Thurner, S.

2015-01-01

The inability to see and quantify systemic financial risk comes at an immense social cost. Systemic risk in the financial system arises to a large extent as a consequence of the interconnectedness of its institutions, which are linked through networks of different types of financial contracts, such

The Price of Anarchy in Network Creation Games Is (Mostly) Constant

Science.gov (United States)

Mihalák, Matúš; Schlegel, Jan Christoph

We study the price of anarchy and the structure of equilibria in network creation games. A network creation game (first defined and studied by Fabrikant et al. [4]) is played by n players {1,2,...,n}, each identified with a vertex of a graph (network), where the strategy of player i, i = 1,...,n, is to build some edges adjacent to i. The cost of building an edge is α> 0, a fixed parameter of the game. The goal of every player is to minimize its creation cost plus its usage cost. The creation cost of player i is α times the number of built edges. In the SumGame (the original variant of Fabrikant et al. [4]) the usage cost of player i is the sum of distances from i to every node of the resulting graph. In the MaxGame (variant defined and studied by Demaine et al. [3]) the usage cost is the eccentricity of i in the resulting graph of the game. In this paper we improve previously known bounds on the price of anarchy of the game (of both variants) for various ranges of α, and give new insights into the structure of equilibria for various values of α. The two main results of the paper show that for α > 273·n all equilibria in SumGame are trees and thus the price of anarchy is constant, and that for α> 129 all equilibria in MaxGame are trees and the price of anarchy is constant. For SumGame this (almost) answers one of the basic open problems in the field - is price of anarchy of the network creation game constant for all values of α? - in an affirmative way, up to a tiny range of α.

Low-cost RAU with Optical Power Supply Used in a Hybrid RoF IEEE 802.11 Network

Science.gov (United States)

Kowalczyk, M.; Siuzdak, J.

2014-09-01

The paper presents design and implementation of a low-cost RAU (Remote Antenna Unit) device. It was designed to work in a hybrid Wi-Fi/optical network based on the IEEE 802.11b/g standard. An unique feature of the device is the possibility of optical power supply.

CREATION OF EXPORT-ORIENTED NETWORK OF GRAIN ELEVATORS IN UKRAINE

Directory of Open Access Journals (Sweden)

D. M. Kozachenko

2017-04-01

Full Text Available Purpose. The scientific paper highlights improving the efficiency of export rail transportation of grain cargoes in Ukraine by introducing shipper routing and concentration of loading at the terminal grain elevators. Methodology. According to the experience of the USA and Canada, one of the most effective ways to reduce costs in the grain to-port supply chain is a shipper routing of the rail traffic. Shipper routing for transportation of grain cargoes involves the concentration of their loading on the multiple junctions. The junctions are proposed to be selected with the use of cluster analysis methods. For the formation of the grain loading concentration areas the authors used methods of set theory and multi-criteria optimization. Findings. Based on agglomerative cluster analysis algorithm, the junctions on a network of Ukrainian railways are selected and the areas of possible concentration of grain loading are formed. DSU-algorithm allowed distinguishing the overlapping and non-overlapping areas of concentration. The problem of selecting non-overlapping areas of the grain loading concentration is formalized as the problem of multiobjective integer programming with boolean variables. The solution of this problem by a modified simplex algorithm allows selecting on the railway network of Ukraine 24 districts of possible grain loading concentration, which cover 70 stations and at minimal additional cost provide routing of about 7.5 million tons of grain per year. Originality. The originality of the work lies in the fact that the authors developed the mathematical procedure for selection of junctions and concentration areas of grain loading at the Ukrainian railway network, taking into account the economic efficiency of the process. Practicalvalue. Application of the developed method of grain loading concentration for the formation of unit trains will significantly reduce the logistics costs in the supply chain of grain to Ukrainian ports for

Searching for the most cost-effective strategy for controlling epidemics spreading on regular and small-world networks.

Science.gov (United States)

Kleczkowski, Adam; Oleś, Katarzyna; Gudowska-Nowak, Ewa; Gilligan, Christopher A

2012-01-07

We present a combined epidemiological and economic model for control of diseases spreading on local and small-world networks. The disease is characterized by a pre-symptomatic infectious stage that makes detection and control of cases more difficult. The effectiveness of local (ring-vaccination or culling) and global control strategies is analysed by comparing the net present values of the combined cost of preventive treatment and illness. The optimal strategy is then selected by minimizing the total cost of the epidemic. We show that three main strategies emerge, with treating a large number of individuals (global strategy, GS), treating a small number of individuals in a well-defined neighbourhood of a detected case (local strategy) and allowing the disease to spread unchecked (null strategy, NS). The choice of the optimal strategy is governed mainly by a relative cost of palliative and preventive treatments. If the disease spreads within the well-defined neighbourhood, the local strategy is optimal unless the cost of a single vaccine is much higher than the cost associated with hospitalization. In the latter case, it is most cost-effective to refrain from prevention. Destruction of local correlations, either by long-range (small-world) links or by inclusion of many initial foci, expands the range of costs for which the NS is most cost-effective. The GS emerges for the case when the cost of prevention is much lower than the cost of treatment and there is a substantial non-local component in the disease spread. We also show that local treatment is only desirable if the disease spreads on a small-world network with sufficiently few long-range links; otherwise it is optimal to treat globally. In the mean-field case, there are only two optimal solutions, to treat all if the cost of the vaccine is low and to treat nobody if it is high. The basic reproduction ratio, R(0), does not depend on the rate of responsive treatment in this case and the disease always invades

The BErkeley Atmospheric CO2 Observation Network: field calibration and evaluation of low-cost air quality sensors

Science.gov (United States)

Kim, Jinsol; Shusterman, Alexis A.; Lieschke, Kaitlyn J.; Newman, Catherine; Cohen, Ronald C.

2018-04-01

The newest generation of air quality sensors is small, low cost, and easy to deploy. These sensors are an attractive option for developing dense observation networks in support of regulatory activities and scientific research. They are also of interest for use by individuals to characterize their home environment and for citizen science. However, these sensors are difficult to interpret. Although some have an approximately linear response to the target analyte, that response may vary with time, temperature, and/or humidity, and the cross-sensitivity to non-target analytes can be large enough to be confounding. Standard approaches to calibration that are sufficient to account for these variations require a quantity of equipment and labor that negates the attractiveness of the sensors' low cost. Here we describe a novel calibration strategy for a set of sensors, including CO, NO, NO2, and O3, that makes use of (1) multiple co-located sensors, (2) a priori knowledge about the chemistry of NO, NO2, and O3, (3) an estimate of mean emission factors for CO, and (4) the global background of CO. The strategy requires one or more well calibrated anchor points within the network domain, but it does not require direct calibration of any of the individual low-cost sensors. The procedure nonetheless accounts for temperature and drift, in both the sensitivity and zero offset. We demonstrate this calibration on a subset of the sensors comprising BEACO2N, a distributed network of approximately 50 sensor nodes, each measuring CO2, CO, NO, NO2, O3 and particulate matter at 10 s time resolution and approximately 2 km spacing within the San Francisco Bay Area.

Broadband network selection issues

Science.gov (United States)

Leimer, Michael E.

1996-01-01

Selecting the best network for a given cable or telephone company provider is not as obvious as it appears. The cost and performance trades between Hybrid Fiber Coax (HFC), Fiber to the Curb (FTTC) and Asymmetric Digital Subscriber Line networks lead to very different choices based on the existing plant and the expected interactive subscriber usage model. This paper presents some of the issues and trades that drive network selection. The majority of the Interactive Television trials currently underway or planned are based on HFC networks. As a throw away market trial or a short term strategic incursion into a cable market, HFC may make sense. In the long run, if interactive services see high demand, HFC costs per node and an ever shrinking neighborhood node size to service large numbers of subscribers make FTTC appear attractive. For example, thirty-three 64-QAM modulators are required to fill the 550 MHz to 750 MHz spectrum with compressed video streams in 6 MHz channels. This large amount of hardware at each node drives not only initial build-out costs, but operations and maintenance costs as well. FTTC, with its potential for digitally switching large amounts of bandwidth to an given home, offers the potential to grow with the interactive subscriber base with less downstream cost. Integrated telephony on these networks is an issue that appears to be an afterthought for most of the networks being selected at the present time. The major players seem to be videocentric and include telephony as a simple add-on later. This may be a reasonable view point for the telephone companies that plan to leave their existing phone networks untouched. However, a phone company planning a network upgrade or a cable company jumping into the telephony business needs to carefully weigh the cost and performance issues of the various network choices. Each network type provides varying capability in both upstream and downstream bandwidth for voice channels. The noise characteristics

Comparing multilayer brain networks between groups: Introducing graph metrics and recommendations.

Science.gov (United States)

Mandke, Kanad; Meier, Jil; Brookes, Matthew J; O'Dea, Reuben D; Van Mieghem, Piet; Stam, Cornelis J; Hillebrand, Arjan; Tewarie, Prejaas

2018-02-01

There is an increasing awareness of the advantages of multi-modal neuroimaging. Networks obtained from different modalities are usually treated in isolation, which is however contradictory to accumulating evidence that these networks show non-trivial interdependencies. Even networks obtained from a single modality, such as frequency-band specific functional networks measured from magnetoencephalography (MEG) are often treated independently. Here, we discuss how a multilayer network framework allows for integration of multiple networks into a single network description and how graph metrics can be applied to quantify multilayer network organisation for group comparison. We analyse how well-known biases for single layer networks, such as effects of group differences in link density and/or average connectivity, influence multilayer networks, and we compare four schemes that aim to correct for such biases: the minimum spanning tree (MST), effective graph resistance cost minimisation, efficiency cost optimisation (ECO) and a normalisation scheme based on singular value decomposition (SVD). These schemes can be applied to the layers independently or to the multilayer network as a whole. For correction applied to whole multilayer networks, only the SVD showed sufficient bias correction. For correction applied to individual layers, three schemes (ECO, MST, SVD) could correct for biases. By using generative models as well as empirical MEG and functional magnetic resonance imaging (fMRI) data, we further demonstrated that all schemes were sensitive to identify network topology when the original networks were perturbed. In conclusion, uncorrected multilayer network analysis leads to biases. These biases may differ between centres and studies and could consequently lead to unreproducible results in a similar manner as for single layer networks. We therefore recommend using correction schemes prior to multilayer network analysis for group comparisons. Copyright © 2017 Elsevier

Impacts of battery characteristics, driver preferences and road network features on travel costs of a plug-in hybrid electric vehicle (PHEV) for long-distance trips

International Nuclear Information System (INIS)

Arslan, Okan; Yıldız, Barış; Ekin Karaşan, Oya

2014-01-01

In a road network with refueling and fast charging stations, the minimum-cost driving path of a plug-in hybrid electric vehicle (PHEV) depends on factors such as location and availability of refueling/fast charging stations, capacity and cost of PHEV batteries, and driver tolerance towards extra mileage or additional stopping. In this paper, our focus is long-distance trips of PHEVs. We analyze the impacts of battery characteristics, often-overlooked driver preferences and road network features on PHEV travel costs for long-distance trips and compare the results with hybrid electric and conventional vehicles. We investigate the significance of these factors and derive critical managerial insights for shaping the future investment decisions about PHEVs and their infrastructure. In particular, our findings suggest that with a certain level of deployment of fast charging stations, well established cost and emission benefits of PHEVs for the short range trips can be extended to long distance. Drivers' stopping intolerance may hamper these benefits; however, increasing battery capacity may help overcome the adverse effects of this intolerance. - Highlights: • We investigate the travel costs of CVs, HEVs and PHEVs for long-distance trips. • We analyze the impacts of battery, driver and road network characteristics on the costs. • We provide critical managerial insights to shape the investment decisions about PHEVs. • Drivers' stopping intolerance may hamper the cost and emission benefits of PHEVs. • Negative effect of intolerance on cost may be overcome by battery capacity expansion

IP communication optimization for 6LoWPAN-Based Wireless Sensor Networks

Directory of Open Access Journals (Sweden)

Li MA

2014-07-01

Full Text Available The emergence of 6LoWPAN makes it possible that Wireless Sensor Networks access to the Internet. However, the cost of IP communication between 6LoWPAN wireless sensor node and external internet node is still relatively high. This paper proposed a new addressing configuration and compression scheme in 6LoWPAN network called IPHC-NAT, which largely reduced the proportion of the IP header in 6LoWPAN packet, designed and constructed a bidirectional data transmission gateway to connect 6LoWPAN wireless sensor node with IPv6 client. The experimental results show the feasibility of the design of IPHC-NAT and the data transmission efficiency has significantly been improved compared to the original 6LoWPAN network.

A Space-Time Network-Based Modeling Framework for Dynamic Unmanned Aerial Vehicle Routing in Traffic Incident Monitoring Applications

Directory of Open Access Journals (Sweden)

Jisheng Zhang

2015-06-01

Full Text Available It is essential for transportation management centers to equip and manage a network of fixed and mobile sensors in order to quickly detect traffic incidents and further monitor the related impact areas, especially for high-impact accidents with dramatic traffic congestion propagation. As emerging small Unmanned Aerial Vehicles (UAVs start to have a more flexible regulation environment, it is critically important to fully explore the potential for of using UAVs for monitoring recurring and non-recurring traffic conditions and special events on transportation networks. This paper presents a space-time network- based modeling framework for integrated fixed and mobile sensor networks, in order to provide a rapid and systematic road traffic monitoring mechanism. By constructing a discretized space-time network to characterize not only the speed for UAVs but also the time-sensitive impact areas of traffic congestion, we formulate the problem as a linear integer programming model to minimize the detection delay cost and operational cost, subject to feasible flying route constraints. A Lagrangian relaxation solution framework is developed to decompose the original complex problem into a series of computationally efficient time-dependent and least cost path finding sub-problems. Several examples are used to demonstrate the results of proposed models in UAVs’ route planning for small and medium-scale networks.

Energy-aware virtual network embedding in flexi-grid networks.

Science.gov (United States)

Lin, Rongping; Luo, Shan; Wang, Haoran; Wang, Sheng

2017-11-27

Network virtualization technology has been proposed to allow multiple heterogeneous virtual networks (VNs) to coexist on a shared substrate network, which increases the utilization of the substrate network. Efficiently mapping VNs on the substrate network is a major challenge on account of the VN embedding (VNE) problem. Meanwhile, energy efficiency has been widely considered in the network design in terms of operation expenses and the ecological awareness. In this paper, we aim to solve the energy-aware VNE problem in flexi-grid optical networks. We provide an integer linear programming (ILP) formulation to minimize the electricity cost of each arriving VN request. We also propose a polynomial-time heuristic algorithm where virtual links are embedded sequentially to keep a reasonable acceptance ratio and maintain a low electricity cost. Numerical results show that the heuristic algorithm performs closely to the ILP for a small size network, and we also demonstrate its applicability to larger networks.

Towards Scalable Cost-Effective Service and Survivability Provisioning in Ultra High Speed Networks

Energy Technology Data Exchange (ETDEWEB)

Bin Wang

2006-12-01

Optical transport networks based on wavelength division multiplexing (WDM) are considered to be the most appropriate choice for future Internet backbone. On the other hand, future DOE networks are expected to have the ability to dynamically provision on-demand survivable services to suit the needs of various high performance scientific applications and remote collaboration. Since a failure in aWDMnetwork such as a cable cut may result in a tremendous amount of data loss, efficient protection of data transport in WDM networks is therefore essential. As the backbone network is moving towards GMPLS/WDM optical networks, the unique requirement to support DOE’s science mission results in challenging issues that are not directly addressed by existing networking techniques and methodologies. The objectives of this project were to develop cost effective protection and restoration mechanisms based on dedicated path, shared path, preconfigured cycle (p-cycle), and so on, to deal with single failure, dual failure, and shared risk link group (SRLG) failure, under different traffic and resource requirement models; to devise efficient service provisioning algorithms that deal with application specific network resource requirements for both unicast and multicast; to study various aspects of traffic grooming in WDM ring and mesh networks to derive cost effective solutions while meeting application resource and QoS requirements; to design various diverse routing and multi-constrained routing algorithms, considering different traffic models and failure models, for protection and restoration, as well as for service provisioning; to propose and study new optical burst switched architectures and mechanisms for effectively supporting dynamic services; and to integrate research with graduate and undergraduate education. All objectives have been successfully met. This report summarizes the major accomplishments of this project. The impact of the project manifests in many aspects: First

A Portable Low-Cost High Density Sensor Network for Air Quality at London Heathrow Airport

Science.gov (United States)

Popoola, Olalekan; Mead, Iq; Bright, Vivien; Baron, Ronan; Saffell, John; Stewart, Gregor; Kaye, Paul; Jones, Roderic

2013-04-01

Outdoor air quality and its impact on human health and the environment have been well studied and it has been projected that poor air quality will surpass poor sanitation as the major course of environmental premature mortality by 2050 (IGAC / IGBP, release statement, 2012). Transport-related pollution has been regulated at various levels by enactment of legislations at local, national, regional and global stages. As part of the mitigation measures, routine measurements of atmospheric pollutants such as carbon monoxide (CO), nitric oxide (NO) and nitrogen dioxide (NO2) have to be established in areas where air quality problems are identified. In addition, emission inventories are also generated for different atmospheric environments including urban areas and airport environments required for air quality models. Whilst recognising that most of the existing sparse monitoring networks provide high temporal measurements, spatial data of these highly variable pollutants are not captured, making it difficult to adequately characterise the highly heterogeneous air quality. Spatial information is often obtained from model data which can only be constrained using measurements from the sparse monitoring networks. The work presented here shows the application of low-cost sensor networks aimed at addressing this missing spatial information. We have shown in previous studies the application of low-cost electrochemical sensor network instruments in monitoring road transport pollutants including CO, NO and NO2 in an urban environment (Mead et. al. 2012, accepted Atmospheric Environment). Modified versions of these instruments which include additional species such as O3, SO2, VOCs and CO2 are currently deployed at London Heathrow Airport (LHR) as part of the Sensor Network for Air Quality (SNAQ) project. Meteorology data such as temperature, relative humidity, wind speed and direction are also measured as well as size-speciated particulates (0.38 to 17.4 µm). A network of 50

Origin of the Cosmic Network: Nature vs Nurture

OpenAIRE

Shandarin, Sergei; Habib, Salman; Heitmann, Katrin

2009-01-01

The large-scale structure of the Universe, as traced by the distribution of galaxies, is now being revealed by large-volume cosmological surveys. The structure is characterized by galaxies distributed along filaments, the filaments connecting in turn to form a percolating network. Our objective here is to quantitatively specify the underlying mechanisms that drive the formation of the cosmic network: By combining percolation-based analyses with N-body simulations of gravitational structure fo...

A novel beamforming based model of coverage and transmission costing in IEEE 802.11 WLAN networks

Directory of Open Access Journals (Sweden)

Mehdi Guessous

2017-09-01

Full Text Available IEEE 802.11 WLAN indoor networks face major inherent and environmental issues such as interference, noise, and obstacles. At the same time, they must provide a maximal service performance in highly changing radio environments and conformance to various applications’ requirements. For this purpose, they require a solid design approach that considers both inputs from the radio interface and the upper-layer services at every design step. The modelization of radio area coverage is a key component in this process and must build on feasible work hypotheses. It should be able also to interpret highly varying characteristics of dense indoor environments, technology advances, service design best practices, end-to-end integration with other network parts: Local Area Network (LAN, Wide Area Network (WAN or Data Center Network (DCN. This work focuses on Radio Resource Management (RRM as a key tool to achieve a solid design in WLAN indoor environments by planning frequency channel assignment, transmit directions and corresponding power levels. Its scope is limited to tackle co-channel interference but can be easily extended to address cross-channel ones. In this paper, we consider beamforming and costing techniques to augment conventional RRM’s Transmit Power Control (TPC procedures that market-leading vendors has implemented and related research has worked on. We present a novel approach of radio coverage modelization and prove its additions to the cited related-work’s models. Our solution model runs three algorithms to evaluate transmission opportunities of Wireless Devices (WD under the coverage area. It builds on realistic hypotheses and a thorough system operation’s understanding to evaluate such an opportunity to transmit, overcomes limitations from compared related-work’s models, and integrates a hierarchical costing system to match Service Level Agreement (SLA expectations. The term “opportunity” in this context relates also to the new

Maximum Parsimony on Phylogenetic networks

Science.gov (United States)

2012-01-01

Background Phylogenetic networks are generalizations of phylogenetic trees, that are used to model evolutionary events in various contexts. Several different methods and criteria have been introduced for reconstructing phylogenetic trees. Maximum Parsimony is a character-based approach that infers a phylogenetic tree by minimizing the total number of evolutionary steps required to explain a given set of data assigned on the leaves. Exact solutions for optimizing parsimony scores on phylogenetic trees have been introduced in the past. Results In this paper, we define the parsimony score on networks as the sum of the substitution costs along all the edges of the network; and show that certain well-known algorithms that calculate the optimum parsimony score on trees, such as Sankoff and Fitch algorithms extend naturally for networks, barring conflicting assignments at the reticulate vertices. We provide heuristics for finding the optimum parsimony scores on networks. Our algorithms can be applied for any cost matrix that may contain unequal substitution costs of transforming between different characters along different edges of the network. We analyzed this for experimental data on 10 leaves or fewer with at most 2 reticulations and found that for almost all networks, the bounds returned by the heuristics matched with the exhaustively determined optimum parsimony scores. Conclusion The parsimony score we define here does not directly reflect the cost of the best tree in the network that displays the evolution of the character. However, when searching for the most parsimonious network that describes a collection of characters, it becomes necessary to add additional cost considerations to prefer simpler structures, such as trees over networks. The parsimony score on a network that we describe here takes into account the substitution costs along the additional edges incident on each reticulate vertex, in addition to the substitution costs along the other edges which are

Network architecture in a converged optical + IP network

Science.gov (United States)

Wakim, Walid; Zottmann, Harald

2012-01-01

As demands on Provider Networks continue to grow at exponential rates, providers are forced to evaluate how to continue to grow the network while increasing service velocity, enhancing resiliency while decreasing the total cost of ownership (TCO). The bandwidth growth that networks are experiencing is in the form packet based multimedia services such as video, video conferencing, gaming, etc... mixed with Over the Top (OTT) content providers such as Netflix, and the customer's expectations that best effort is not enough you end up with a situation that forces the provider to analyze how to gain more out of the network with less cost. In this paper we will discuss changes in the network that are driving us to a tighter integration between packet and optical layers and how to improve on today's multi - layer inefficiencies to drive down network TCO and provide for a fully integrated and dynamic network that will decrease time to revenue.

Tunable optical frequency comb enabled scalable and cost-effective multiuser orthogonal frequency-division multiple access passive optical network with source-free optical network units.

Science.gov (United States)

Chen, Chen; Zhang, Chongfu; Liu, Deming; Qiu, Kun; Liu, Shuang

2012-10-01

We propose and experimentally demonstrate a multiuser orthogonal frequency-division multiple access passive optical network (OFDMA-PON) with source-free optical network units (ONUs), enabled by tunable optical frequency comb generation technology. By cascading a phase modulator (PM) and an intensity modulator and dynamically controlling the peak-to-peak voltage of a PM driven signal, a tunable optical frequency comb source can be generated. It is utilized to assist the configuration of a multiple source-free ONUs enhanced OFDMA-PON where simultaneous and interference-free multiuser upstream transmission over a single wavelength can be efficiently supported. The proposed multiuser OFDMA-PON is scalable and cost effective, and its feasibility is successfully verified by experiment.

Congestion control and routing over satellite networks

Science.gov (United States)

Cao, Jinhua

Satellite networks and transmissions find their application in fields of computer communications, telephone communications, television broadcasting, transportation, space situational awareness systems and so on. This thesis mainly focuses on two networking issues affecting satellite networking: network congestion control and network routing optimization. Congestion, which leads to long queueing delays, packet losses or both, is a networking problem that has drawn the attention of many researchers. The goal of congestion control mechanisms is to ensure high bandwidth utilization while avoiding network congestion by regulating the rate at which traffic sources inject packets into a network. In this thesis, we propose a stable congestion controller using data-driven, safe switching control theory to improve the dynamic performance of satellite Transmission Control Protocol/Active Queue Management (TCP/AQM) networks. First, the stable region of the Proportional-Integral (PI) parameters for a nominal model is explored. Then, a PI controller, whose parameters are adaptively tuned by switching among members of a given candidate set, using observed plant data, is presented and compared with some classical AQM policy examples, such as Random Early Detection (RED) and fixed PI control. A new cost detectable switching law with an interval cost function switching algorithm, which improves the performance and also saves the computational cost, is developed and compared with a law commonly used in the switching control literature. Finite-gain stability of the system is proved. A fuzzy logic PI controller is incorporated as a special candidate to achieve good performance at all nominal points with the available set of candidate controllers. Simulations are presented to validate the theory. An effocient routing algorithm plays a key role in optimizing network resources. In this thesis, we briefly analyze Low Earth Orbit (LEO) satellite networks, review the Cross Entropy (CE

FttC-Based Fronthaul for 5G Dense/Ultra-Dense Access Network: Performance and Costs in Realistic Scenarios

Directory of Open Access Journals (Sweden)

Franco Mazzenga

2017-10-01

Full Text Available One distinctive feature of the next 5G systems is the presence of a dense/ultra-dense wireless access network with a large number of access points (or nodes at short distances from each other. Dense/ultra-dense access networks allow for providing very high transmission capacity to terminals. However, the deployment of dense/ultra-dense networks is slowed down by the cost of the fiber-based infrastructure required to connect radio nodes to the central processing units and then to the core network. In this paper, we investigate the possibility for existing FttC access networks to provide fronthaul capabilities for dense/ultra-dense 5G wireless networks. The analysis is realistic in that it is carried out considering an actual access network scenario, i.e., the Italian FttC deployment. It is assumed that access nodes are connected to the Cabinets and to the corresponding distributors by a number of copper pairs. Different types of cities grouped in terms of population have been considered. Results focus on fronthaul transport capacity provided by the FttC network and have been expressed in terms of the available fronthaul bit rate per node and of the achievable coverage.

Circles of Health: towards an advanced social network about disabilities of neurological origin.

Science.gov (United States)

Subirats, Laia; Ceccaroni, Luigi; Lopez-Blazquez, Raquel; Miralles, Felip; García-Rudolph, Alejandro; Tormos, Jose M

2013-12-01

This research is concerned with the study of a new social-network platform, which (1) provides people with disabilities of neurological origin, their relatives, health professionals, therapists, carers and institutions with an interoperable platform that supports standard indicators, (2) promotes knowledge democratization and user empowerment, and (3) allows making decisions with a more informed opinion. A new social network, Circles of Health, has been designed, developed and tested by end-users. To allow monitoring the evolution of people's health status and comparing it with other users and with their cohort, anonymized data of 2675 people from comprehensive and multidimensional medical evaluations, carried out yearly from 2006 to 2010, have been standardized to the International Classification of Functioning, Disability and Health, integrated into the corresponding medical health records and then used to automatically generate and graphically represent multidimensional indicators. These indicators have been integrated into Circles of Health's social environment, which has been then evaluated via expert and user-experience analyses. Patients used Circles of Health to exchange bio-psycho-social information (medical and otherwise) about their everyday lives. Health professionals remarked that the use of color-coding in graphical representations is useful to quickly diagnose deficiencies, difficulties or barriers in rehabilitation. Most people with disabilities complained about the excessive amount of information and the difficulty in interpreting graphical representations. Health professionals found Circles of Health useful to generate a more integrative understanding of health based on a comprehensive profile of individuals instead of being focused on patient's diseases and injuries. People with disabilities found enriching personal knowledge with the experiences of other users helpful. The number of descriptors used at the same time in the graphical interface

Coauthorship and institutional collaborations on cost-effectiveness analyses: a systematic network analysis.

Directory of Open Access Journals (Sweden)

Ferrán Catalá-López

Full Text Available BACKGROUND: Cost-Effectiveness Analysis (CEA has been promoted as an important research methodology for determining the efficiency of healthcare technology and guiding medical decision-making. Our aim was to characterize the collaborative patterns of CEA conducted over the past two decades in Spain. METHODS AND FINDINGS: A systematic analysis was carried out with the information obtained through an updated comprehensive literature review and from reports of health technology assessment agencies. We identified CEAs with outcomes expressed as a time-based summary measure of population health (e.g. quality-adjusted life-years or disability-adjusted life-years, conducted in Spain and published between 1989 and 2011. Networks of coauthorship and institutional collaboration were produced using PAJEK software. One-hundred and thirty-one papers were analyzed, in which 526 authors and 230 institutions participated. The overall signatures per paper index was 5.4. Six major groups (one with 14 members, three with 7 members and two with 6 members were identified. The most prolific authors were generally affiliated with the private-for-profit sector (e.g. consulting firms and the pharmaceutical industry. The private-for-profit sector maintains profuse collaborative networks including public hospitals and academia. Collaboration within the public sector (e.g. healthcare administration and primary care was weak and fragmented. CONCLUSIONS: This empirical analysis reflects critical practices among collaborative networks that contributed substantially to the production of CEA, raises challenges for redesigning future policies and provides a framework for similar analyses in other regions.

Generating original ideas: The neural underpinning of originality.

Science.gov (United States)

Mayseless, Naama; Eran, Ayelet; Shamay-Tsoory, Simone G

2015-08-01

One of the key aspects of creativity is the ability to produce original ideas. Originality is defined in terms of the novelty and rarity of an idea and is measured by the infrequency of the idea compared to other ideas. In the current study we focused on divergent thinking (DT) - the ability to produce many alternate ideas - and assessed the neural pathways associated with originality. Considering that generation of original ideas involves both the ability to generate new associations and the ability to overcome automatic common responses, we hypothesized that originality would be associated with activations in regions related to associative thinking, including areas of the default mode network (DMN) such as medial prefrontal areas, as well as with areas involved in cognitive control and inhibition. Thirty participants were scanned while performing a DT task that required the generation of original uses for common objects. The results indicate that the ability to produce original ideas is mediated by activity in several regions that are part of the DMN including the medial prefrontal cortex (mPFC) and the posterior cingulate cortex (PCC). Furthermore, individuals who are more original exhibited enhanced activation in the ventral anterior cingulate cortex (vACC), which was also positively coupled with activity in the left occipital-temporal area. These results are in line with the dual model of creativity, according to which original ideas are a product of the interaction between a system that generates ideas and a control system that evaluates these ideas. Copyright © 2015 Elsevier Inc. All rights reserved.

Validation of the OpCost logging cost model using contractor surveys

Science.gov (United States)

Conor K. Bell; Robert F. Keefe; Jeremy S. Fried

2017-01-01

OpCost is a harvest and fuel treatment operations cost model developed to function as both a standalone tool and an integrated component of the Bioregional Inventory Originated Simulation Under Management (BioSum) analytical framework for landscape-level analysis of forest management alternatives. OpCost is an updated implementation of the Fuel Reduction Cost Simulator...

Transaction costs economics of irreplaceability: ex ante and ex post evaluation of conservation networks' vulnerability to environmental shocks.

Science.gov (United States)

Huusom, Henrik; Strange, Niels

2008-04-01

The theoretical concept, "asset specificity," is applied to real data in the context of Danish nature conservation network planning in order to produce illustrative examples of an economic measure of the network's vulnerability to exogenous shocks to the species composition. Three different measures of asset specificity are quantified from the shadow value of eliminating a key species from the individual grid cells. This represents a novel approach and a different interpretation of the term, as it is conventionally used as a qualitative indicator in the transaction cost economics literature. Apart from supplementing existing cost measures with an indicator of risk associated with investments in protected areas, this study demonstrates how the estimation and interpretation of various asset specificity measures for geographical areas may qualify policy makers' choice of policy instrument in conservation planning. This differs from the more intuitive approach of basing policy instrument choice solely on the rarity of the species in a given area.

Low-Cost Ground Sensor Network for Intrusion Detection

Science.gov (United States)

2017-09-01

their suitability to our research. 1. Wireless Sensor Networks The backend network infrastructure forms the communication links for the network...were not ideal as they were perpetually turned on. Our research considered the backend communication infrastructure and its power requirements when...7 3. Border Patrol— Mobile Situation Awareness Tool (MSAT

A cost-effective measurement-device-independent quantum key distribution system for quantum networks

Science.gov (United States)

Valivarthi, Raju; Zhou, Qiang; John, Caleb; Marsili, Francesco; Verma, Varun B.; Shaw, Matthew D.; Nam, Sae Woo; Oblak, Daniel; Tittel, Wolfgang

2017-12-01

We experimentally realize a measurement-device-independent quantum key distribution (MDI-QKD) system. It is based on cost-effective and commercially available hardware such as distributed feedback lasers and field-programmable gate arrays that enable time-bin qubit preparation and time-tagging, and active feedback systems that allow for compensation of time-varying properties of photons after transmission through deployed fiber. We examine the performance of our system, and conclude that its design does not compromise performance. Our demonstration paves the way for MDI-QKD-based quantum networks in star-type topology that extend over more than 100 km distance.

Is Cooperative Memory Special? The Role of Costly Errors, Context, and Social Network Size When Remembering Cooperative Actions

Directory of Open Access Journals (Sweden)

Tim Winke

2017-10-01

Full Text Available Theoretical studies of cooperative behavior have focused on decision strategies, such as tit-for-tat, that depend on remembering a partner’s last choices. Yet, an empirical study by Stevens et al. (2011 demonstrated that human memory may not meet the requirements that needed to use these strategies. When asked to recall the previous behavior of simulated partners in a cooperative memory task, participants performed poorly, making errors in 10–24% of the trials. However, we do not know the extent to which this task taps specialized cognition for cooperation. It may be possible to engage participants in more cooperative, strategic thinking, which may improve memory. On the other hand, compared with other situations, a cooperative context may already engage improved memory via cheater detection mechanisms. This study investigated the specificity of memory in cooperative contexts by varying (1 the costs of errors in memory by making forgetting defection more costly and (2 whether the recall situation is framed as a cooperative or neutral context. Also, we investigated whether variation in participants’ social network size could account for individual differences observed in memory accuracy. We found that neither including differential costs for misremembering defection nor removing the cooperative context influenced memory accuracy for cooperation. Combined, these results suggest that memory accuracy is robust to differences in the cooperative context: Adding more strategic components does not help accuracy, and removing cooperative components does not hurt accuracy. Social network size, however, did correlate with memory accuracy: People with larger networks remembered the events better. These findings suggest that cooperative memory does not seem to be special compared with other forms of memory, which aligns with previous work demonstrating the domain generality of memory. However, the demands of interacting in a large social network may

Optical Access Networks

Science.gov (United States)

Zheng, Jun; Ansari, Nirwan

2005-01-01

Call for Papers: Optical Access Networks Guest Editors Jun Zheng, University of Ottawa Nirwan Ansari, New Jersey Institute of Technology Submission Deadline: 1 June 2005 Background With the wide deployment of fiber-optic technology over the past two decades, we have witnessed a tremendous growth of bandwidth capacity in the backbone networks of today's telecommunications infrastructure. However, access networks, which cover the "last-mile" areas and serve numerous residential and small business users, have not been scaled up commensurately. The local subscriber lines for telephone and cable television are still using twisted pairs and coaxial cables. Most residential connections to the Internet are still through dial-up modems operating at a low speed on twisted pairs. As the demand for access bandwidth increases with emerging high-bandwidth applications, such as distance learning, high-definition television (HDTV), and video on demand (VoD), the last-mile access networks have become a bandwidth bottleneck in today's telecommunications infrastructure. To ease this bottleneck, it is imperative to provide sufficient bandwidth capacity in the access networks to open the bottleneck and thus present more opportunities for the provisioning of multiservices. Optical access solutions promise huge bandwidth to service providers and low-cost high-bandwidth services to end users and are therefore widely considered the technology of choice for next-generation access networks. To realize the vision of optical access networks, however, many key issues still need to be addressed, such as network architectures, signaling protocols, and implementation standards. The major challenges lie in the fact that an optical solution must be not only robust, scalable, and flexible, but also implemented at a low cost comparable to that of existing access solutions in order to increase the economic viability of many potential high-bandwidth applications. In recent years, optical access networks

OPTIMAL NETWORK TOPOLOGY DESIGN

Science.gov (United States)

Yuen, J. H.

1994-01-01

This program was developed as part of a research study on the topology design and performance analysis for the Space Station Information System (SSIS) network. 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. It is intended that this new design technique consider all important performance measures explicitly and take into account the constraints due to various technical feasibilities. In the current program, technical constraints are taken care of by the user properly forming the starting set of candidate components (e.g. nonfeasible links are not included). As subsets are generated, they are tested to see if they form an acceptable network by checking that all requirements are satisfied. Thus the first acceptable subset encountered gives the cost-optimal topology satisfying all given constraints. The user must sort the set of "feasible" link elements in increasing order of their costs. The program prompts the user for the following information for each link: 1) cost, 2) connectivity (number of stations connected by the link), and 3) the stations connected by that link. Unless instructed to stop, the program generates all possible acceptable networks in increasing order of their total costs. The program is written only to generate topologies that are simply connected. Tests on reliability, delay, and other performance measures are discussed in the documentation, but have not been incorporated into the program. This program is written in PASCAL for interactive execution and has been implemented on an IBM PC series computer operating under PC DOS. The disk contains source code only. This program was developed in 1985.

Cost considerations

NARCIS (Netherlands)

Michiel Ras; Debbie Verbeek-Oudijk; Evelien Eggink

2013-01-01

Original title: Lasten onder de loep The Dutch government spends almost 7 billion euros  each year on care for people with intellectual disabilities, and these costs are rising steadily. This report analyses what underlies the increase in costs that occurred between 2007 and 2011. Was

Green mobile networks a networking perspective

CERN Document Server

Ansari, Nirwan

2016-01-01

Combines the hot topics of energy efficiency and next generation mobile networking, examining techniques and solutions. Green communications is a very hot topic. Ever increasing mobile network bandwidth rates significantly impacts on operating costs due to aggregate network energy consumption. As such, design on 4G networks and beyond has increasingly started to focus on 'energy efficiency' or so-called 'green' networks. Many techniques and solutions have been proposed to enhance the energy efficiency of mobile networks, yet no book has provided an in-depth analysis of the energy consumption issues in mobile networks nor offers detailed theories, tools and solutions for solving the energy efficiency problems.

Sharing the cost of redundant items

DEFF Research Database (Denmark)

Hougaard, Jens Leth; Moulin, Hervé

2014-01-01

We ask how to share the cost of finitely many public goods (items) among users with different needs: some smaller subsets of items are enough to serve the needs of each user, yet the cost of all items must be covered, even if this entails inefficiently paying for redundant items. Typical examples...... are network connectivity problems when an existing (possibly inefficient) network must be maintained. We axiomatize a family cost ratios based on simple liability indices, one for each agent and for each item, measuring the relative worth of this item across agents, and generating cost allocation rules...... additive in costs....

ORIGINAL ARTICLES

African Journals Online (AJOL)

ORIGINAL ARTICLES. Cost to patients of obtaining treatment for HIV/AIDS in. South Africa. Sydney Rosen, Mpefe Ketlhapile, Ian Sanne, Mary Bachman DeSilva. Background. South Africa is providing antiretroviral (ARV) drugs for HIV I AIDS free of charge in order to increase access for poorer patients and promote ...

Column generation algorithms for virtual network embedding in flexi-grid optical networks.

Science.gov (United States)

Lin, Rongping; Luo, Shan; Zhou, Jingwei; Wang, Sheng; Chen, Bin; Zhang, Xiaoning; Cai, Anliang; Zhong, Wen-De; Zukerman, Moshe

2018-04-16

Network virtualization provides means for efficient management of network resources by embedding multiple virtual networks (VNs) to share efficiently the same substrate network. Such virtual network embedding (VNE) gives rise to a challenging problem of how to optimize resource allocation to VNs and to guarantee their performance requirements. In this paper, we provide VNE algorithms for efficient management of flexi-grid optical networks. We provide an exact algorithm aiming to minimize the total embedding cost in terms of spectrum cost and computation cost for a single VN request. Then, to achieve scalability, we also develop a heuristic algorithm for the same problem. We apply these two algorithms for a dynamic traffic scenario where many VN requests arrive one-by-one. We first demonstrate by simulations for the case of a six-node network that the heuristic algorithm obtains very close blocking probabilities to exact algorithm (about 0.2% higher). Then, for a network of realistic size (namely, USnet) we demonstrate that the blocking probability of our new heuristic algorithm is about one magnitude lower than a simpler heuristic algorithm, which was a component of an earlier published algorithm.

Construction cost estimation of spherical storage tanks: artificial neural networks and hybrid regression—GA algorithms

Science.gov (United States)

Arabzadeh, Vida; Niaki, S. T. A.; Arabzadeh, Vahid

2017-10-01

One of the most important processes in the early stages of construction projects is to estimate the cost involved. This process involves a wide range of uncertainties, which make it a challenging task. Because of unknown issues, using the experience of the experts or looking for similar cases are the conventional methods to deal with cost estimation. The current study presents data-driven methods for cost estimation based on the application of artificial neural network (ANN) and regression models. The learning algorithms of the ANN are the Levenberg-Marquardt and the Bayesian regulated. Moreover, regression models are hybridized with a genetic algorithm to obtain better estimates of the coefficients. The methods are applied in a real case, where the input parameters of the models are assigned based on the key issues involved in a spherical tank construction. The results reveal that while a high correlation between the estimated cost and the real cost exists; both ANNs could perform better than the hybridized regression models. In addition, the ANN with the Levenberg-Marquardt learning algorithm (LMNN) obtains a better estimation than the ANN with the Bayesian-regulated learning algorithm (BRNN). The correlation between real data and estimated values is over 90%, while the mean square error is achieved around 0.4. The proposed LMNN model can be effective to reduce uncertainty and complexity in the early stages of the construction project.

Overlay networks toward information networking

CERN Document Server

Tarkoma, Sasu

2010-01-01

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

Individual Search and Social Networks

OpenAIRE

Sanjeev Goyal; Stephanie Rosenkranz; Utz Weitzel; Vincent Buskens

2014-01-01

The explosion in online social networks motivates an enquiry into their structure and their welfare effects. A central feature of these networks is information sharing: online social networks lower the cost of getting information from others. These lower costs affect the attractiveness of individual search vis-a-vis a reliance on social networks. The paper reports the findings of an experiment on these effects. Our experiment shows that online networks can have large effects. Information acqu...

Network for development of electroporation-based technologies and treatments: COST TD1104.

Science.gov (United States)

Miklavčič, Damijan

2012-10-01

Exposure of biological cells to a sufficiently strong external electric field results in increased permeability of cell membranes, referred to as "electroporation." Since all types of cells (animal, plant and microorganism) can be effectively electroporated, electroporation is considered to be a universal method and a platform technology. Electroporation has become a widely used technology applicable to, e.g., cancer treatment, gene transfection, food and biomass processing and microbial inactivation. However, despite significant progress in electroporation-based applications, there is a lack of coordination and interdisciplinary exchange of knowledge between researchers from different scientific domains. Thus, critical mass for new major breakthroughs is missing. This is why we decided to establish cooperation between research groups working in different fields of electroporation. Cooperation in Science and Technology (COST), which funds networking and capacity-building activities, presents a perfect framework for such scientific cooperation. This COST action aims at (1) providing necessary steps toward EU cooperation of science and technology to foster basic understanding of electroporation; (2) improving communication between research groups, resulting in streamlining European research and development activities; and (3) enabling development of new and further development of existing electroporation-based applications by integrating multidisciplinary research teams, as well as providing comprehensive training for early-stage researchers. Results of this COST action will provide multiple societal, scientific and technological benefits from improving existing electroporation-based applications to adding new ones in the fields of medicine, biotechnology and environmental preservation.

Network connectivity value.

Science.gov (United States)

Dragicevic, Arnaud; Boulanger, Vincent; Bruciamacchie, Max; Chauchard, Sandrine; Dupouey, Jean-Luc; Stenger, Anne

2017-04-21

In order to unveil the value of network connectivity, we formalize the construction of ecological networks in forest environments as an optimal control dynamic graph-theoretic problem. The network is based on a set of bioreserves and patches linked by ecological corridors. The node dynamics, built upon the consensus protocol, form a time evolutive Mahalanobis distance weighted by the opportunity costs of timber production. We consider a case of complete graph, where the ecological network is fully connected, and a case of incomplete graph, where the ecological network is partially connected. The results show that the network equilibrium depends on the size of the reception zone, while the network connectivity depends on the environmental compatibility between the ecological areas. Through shadow prices, we find that securing connectivity in partially connected networks is more expensive than in fully connected networks, but should be undertaken when the opportunity costs are significant. Copyright © 2017 Elsevier Ltd. All rights reserved.

DESIGNING OF AN AUTOMOBILE FLEET NETWORK

Directory of Open Access Journals (Sweden)

R. B. Ivut

2016-01-01

Full Text Available Investment volume is considered as an important factor in regional development under current conditions. Logistical infrastructure which ensures a complex transport, distributive, information and other services exerts a significant influence on regional investment attractiveness. Lack of clear vision on development and execution of development strategy for logistics infrastructure from the side of regional authorities results in unwillingness of large federal and transnational companies to provide investments in infrastructure projects. Network of automotive transport terminals is one of the main elements in logistics infrastructure. The network allows to optimize a flow of material goods from the point of their origin to the point of their consumption with the lowest possible costs and the required level of service. Automobile transport is one of the main objects of transport infrastructure and it is characterized by rather high flexibility in comparison with other types of transport facilities that preconditions its widespread application. Network of automobile fleets (terminals has been formed for redistribution of goods traffic within the concerned regions. The purpose of the present research is to develop a mathematical model for formation of transport infrastructure on the territory of regions. The paper proposes an approach for formation of automobile fleet (terminal network on the territory of a large region with due account of the established network of distribution and sorting-out warehouse facilities. A model has been developed for solving the problem pertaining to minimization of aggregate costs related to maintenance of automobile fleets, delivery of goods to and from distribution and sorting-out warehouse facilities to consumers, ferry of empty trucks and goods handling. The model makes it possible to determine optimal number and location area of automobile fleets (terminals while accounting for their possible locations, capacity

Comprehensive Cost Minimization in Distribution Networks Using Segmented-time Feeder Reconfiguration and Reactive Power Control of Distributed Generators

DEFF Research Database (Denmark)

Chen, Shuheng; Hu, Weihao; Chen, Zhe

2016-01-01

In this paper, an efficient methodology is proposed to deal with segmented-time reconfiguration problem of distribution networks coupled with segmented-time reactive power control of distributed generators. The target is to find the optimal dispatching schedule of all controllable switches...... and distributed generators’ reactive powers in order to minimize comprehensive cost. Corresponding constraints, including voltage profile, maximum allowable daily switching operation numbers (MADSON), reactive power limits, and so on, are considered. The strategy of grouping branches is used to simplify...... (FAHPSO) is implemented in VC++ 6.0 program language. A modified version of the typical 70-node distribution network and several real distribution networks are used to test the performance of the proposed method. Numerical results show that the proposed methodology is an efficient method for comprehensive...

The economic effect of electricity net-metering with solar PV: Consequences for network cost recovery, cross subsidies and policy objectives

International Nuclear Information System (INIS)

Eid, Cherrelle; Reneses Guillén, Javier; Frías Marín, Pablo; Hakvoort, Rudi

2014-01-01

Net-metering is commonly known as a practice by which owners of distributed generation (DG) units may offset their electricity consumption from the grid with local generation. The increasing number of prosumers (consumers that both produce and consume electricity) with solar photovoltaic (PV) generation combined with net-metering results in reduced incomes for many network utilities worldwide. Consequently, this pushes utilities to increase charges per kW h in order to recover costs. For non-PV owners, this could result into inequality issues due to the fact that also non-PV owners have to pay higher chargers for their electricity consumed to make up for netted costs of PV-owners. In order to provide insight in those inequality issues caused by net-metering, this study presents the effects on cross-subsidies, cost recovery and policy objectives evolving from different applied netmetering and tariff designs for a residential consumer. Eventually this paper provides recommendations regarding tariffs and metering that will result in more explicit incentives for PV, instead of the current implicit incentives which are present to PV owners due to net-metering. - Highlights: • Network users are frequently charged by energy charging and fixed charging. • Net-metering with energy charging causes potential problems for DSO cost recovery. • Increasing rolling credit timeframes amplify net-metering impacts on cost recovery. • Observed capacity charging can incentivize local storage and self-consumption. • PV owners should receive direct incentives in order to avoid cross subsidization

Robustness of airline route networks

Science.gov (United States)

Lordan, Oriol; Sallan, Jose M.; Escorihuela, Nuria; Gonzalez-Prieto, David

2016-03-01

Airlines shape their route network by defining their routes through supply and demand considerations, paying little attention to network performance indicators, such as network robustness. However, the collapse of an airline network can produce high financial costs for the airline and all its geographical area of influence. The aim of this study is to analyze the topology and robustness of the network route of airlines following Low Cost Carriers (LCCs) and Full Service Carriers (FSCs) business models. Results show that FSC hubs are more central than LCC bases in their route network. As a result, LCC route networks are more robust than FSC networks.

On the track of fish batches in three distribution networks

DEFF Research Database (Denmark)

Randrup, Maria; Wu, Haiping; Jørgensen, Bo M.

2012-01-01

Three fish products sampled in retail shops were traced back to their origin and fish from the same batch were tracked forward towards the retailer, thereby simulating a recall situation. The resulting distribution networks were very complex, but to the extent that companies were willing to provi...... of discovering a fault as early as possible in order to minimise the costs of a recall. The localisation of distributed products during a recall operation can be facilitated by a well-constructed traceability system....

Business Networks and Inward FDI Policy

OpenAIRE

Fergal McCann

2008-01-01

I outline the effect of business networks on trade, FDI and welfare in a two-country, two-firm duopoly. The network effect, following Greaney (2002), is modelled as a marginal cost disadvantage facing a firm from Foreign in selling to Home. Unlike traditional trade costs, this cost cannot be avoided by investing in Home. My main addition is a Nash game between governments in which they subsidise the fixed costs of inward FDI. While the network effect is shown to lead to favourable outcomes fo...

Transnational networks as a migration strategy. Algerians in the Ebro riverside / Redes transnacionales como estrategia migratoria. Argelinos en la ribera del Ebro

Directory of Open Access Journals (Sweden)

Anna Mata Romeu

2015-10-01

Full Text Available Networks can serve to cushion the weight they have on migrants living costs and disruption involved in immigration; determine, to some extent, who are those who migrate from communities and families; influence the selection of the places of destination and origin; maintaining links with society migrant origin and condition of the integration of migrants into the host society. Our premise is that networks exist and become important within the migration project, both in the way as in the settlement; but its use and intensity is extremely disparate and different, as we refer to one or another immigrant community. We delve into the ways in which they use in the group of Algerian origin settled in Spain, following field work developed in the Autonomous Community of Navarre (Spain between 2002 and 2013.

Wireless mesh networks.

Science.gov (United States)

Wang, Xinheng

2008-01-01

Wireless telemedicine using GSM and GPRS technologies can only provide low bandwidth connections, which makes it difficult to transmit images and video. Satellite or 3G wireless transmission provides greater bandwidth, but the running costs are high. Wireless networks (WLANs) appear promising, since they can supply high bandwidth at low cost. However, the WLAN technology has limitations, such as coverage. A new wireless networking technology named the wireless mesh network (WMN) overcomes some of the limitations of the WLAN. A WMN combines the characteristics of both a WLAN and ad hoc networks, thus forming an intelligent, large scale and broadband wireless network. These features are attractive for telemedicine and telecare because of the ability to provide data, voice and video communications over a large area. One successful wireless telemedicine project which uses wireless mesh technology is the Emergency Room Link (ER-LINK) in Tucson, Arizona, USA. There are three key characteristics of a WMN: self-organization, including self-management and self-healing; dynamic changes in network topology; and scalability. What we may now see is a shift from mobile communication and satellite systems for wireless telemedicine to the use of wireless networks based on mesh technology, since the latter are very attractive in terms of cost, reliability and speed.

Optical storage networking

Science.gov (United States)

Mohr, Ulrich

2001-11-01

For efficient business continuance and backup of mission- critical data an inter-site storage network is required. Where traditional telecommunications costs are prohibitive for all but the largest organizations, there is an opportunity for regional carries to deliver an innovative storage service. This session reveals how a combination of optical networking and protocol-aware SAN gateways can provide an extended storage networking platform with the lowest cost of ownership and the highest possible degree of reliability, security and availability. Companies of every size, with mainframe and open-systems environments, can afford to use this integrated service. Three mayor applications are explained; channel extension, Network Attached Storage (NAS), Storage Area Networks (SAN) and how optical networks address the specific requirements. One advantage of DWDM is the ability for protocols such as ESCON, Fibre Channel, ATM and Gigabit Ethernet, to be transported natively and simultaneously across a single fiber pair, and the ability to multiplex many individual fiber pairs over a single pair, thereby reducing fiber cost and recovering fiber pairs already in use. An optical storage network enables a new class of service providers, Storage Service Providers (SSP) aiming to deliver value to the enterprise by managing storage, backup, replication and restoration as an outsourced service.

The vertebrate Hox gene regulatory network for hindbrain segmentation: Evolution and diversification: Coupling of a Hox gene regulatory network to hindbrain segmentation is an ancient trait originating at the base of vertebrates.

Science.gov (United States)

Parker, Hugo J; Bronner, Marianne E; Krumlauf, Robb

2016-06-01

Hindbrain development is orchestrated by a vertebrate gene regulatory network that generates segmental patterning along the anterior-posterior axis via Hox genes. Here, we review analyses of vertebrate and invertebrate chordate models that inform upon the evolutionary origin and diversification of this network. Evidence from the sea lamprey reveals that the hindbrain regulatory network generates rhombomeric compartments with segmental Hox expression and an underlying Hox code. We infer that this basal feature was present in ancestral vertebrates and, as an evolutionarily constrained developmental state, is fundamentally important for patterning of the vertebrate hindbrain across diverse lineages. Despite the common ground plan, vertebrates exhibit neuroanatomical diversity in lineage-specific patterns, with different vertebrates revealing variations of Hox expression in the hindbrain that could underlie this diversification. Invertebrate chordates lack hindbrain segmentation but exhibit some conserved aspects of this network, with retinoic acid signaling playing a role in establishing nested domains of Hox expression. © 2016 WILEY Periodicals, Inc.

ANN Based Approach for Estimation of Construction Costs of Sports Fields

Directory of Open Access Journals (Sweden)

Michał Juszczyk

2018-01-01

Full Text Available Cost estimates are essential for the success of construction projects. Neural networks, as the tools of artificial intelligence, offer a significant potential in this field. Applying neural networks, however, requires respective studies due to the specifics of different kinds of facilities. This paper presents the proposal of an approach to the estimation of construction costs of sports fields which is based on neural networks. The general applicability of artificial neural networks in the formulated problem with cost estimation is investigated. An applicability of multilayer perceptron networks is confirmed by the results of the initial training of a set of various artificial neural networks. Moreover, one network was tailored for mapping a relationship between the total cost of construction works and the selected cost predictors which are characteristic of sports fields. Its prediction quality and accuracy were assessed positively. The research results legitimatize the proposed approach.

Faith community nursing demonstrates good stewardship of community benefit dollars through cost savings and cost avoidance.

Science.gov (United States)

Brown, Ameldia R; Coppola, Patricia; Giacona, Marian; Petriches, Anne; Stockwell, Mary Ann

2009-01-01

Health systems seeking responsible stewardship of community benefit dollars supporting Faith Community Nursing Networks require demonstration of positive measurable health outcomes. Faith Community Nurses (FCNs) answer the call for measurable outcomes by documenting cost savings and cost avoidances to families, communities, and health systems associated with their interventions. Using a spreadsheet tool based on Medicare reimbursements and diagnostic-related groupings, 3 networks of FCNs have together shown more than 600 000 (for calendar year 2008) healthcare dollars saved by avoidance of unnecessary acute care visits and extended care placements. The cost-benefit ratio of support dollars to cost savings and cost avoidance demonstrates that support of FCNs is good stewardship of community benefit dollars.

The cost of service quality improvements: tracking the flow of funds in social franchise networks in Myanmar

Science.gov (United States)

2013-01-01

Introduction This paper examines the cost of quality improvements in Population Services International (PSI) Myanmar’s social franchise operations from 2007 to 2009. Methods The social franchise commodities studied were products for reproductive health, malaria, STIs, pneumonia, and diarrhea. This project applied ingredients based costing for labor, supplies, transport, and overhead. Data were gathered seven during key informant interviews with staff in the central Yangon office, examination of 3 years of payroll data, examination of a time motion study conducted by PSI, and spreadsheets recording the costs of acquiring and transporting supplies. Results In 2009 PSI Myanmar’s social franchise devoted $2.02 million towards a 94% reduction in commodity prices offered to its network of over 1700 primary care providers. These providers retained 1/3 of the subsidy as revenue and passed along the other 2/3 to their patients in the course of offering subsidized care for 1.5 million health episodes. In addition, PSI Myanmar devoted $2.09 million to support a team of franchise officers who conducted quality assurance for the private providers overseeing service quality and to distributing medical commodities. Conclusion In Myanmar, the social franchise operated by PSI spends roughly $1.00 in quality management and retailing for every $1.00 spent subsidizing medical commodities. Some services are free, but patients also pay fees for other lines of service. Overall patients contribute 1/6 as much as PSI does. Unlike other NGO’s, health services in social franchises like PSI are not all free to the patients, nor are the discounts uniformly applied. Discounts and subsidies evolve in response to public health concerns, market demand, providers’ cost structures as well as strategic objectives in maintaining the network and its portfolio of services. PMID:23826743

The cost of service quality improvements: tracking the flow of funds in social franchise networks in Myanmar.

Science.gov (United States)

Bishai, David; LeFevre, Amnesty; Theuss, Marc; Boxshall, Matt; Hetherington, John D; Zaw, Min; Montagu, Dominic

2013-01-01

This paper examines the cost of quality improvements in Population Services International (PSI) Myanmar's social franchise operations from 2007 to 2009. The social franchise commodities studied were products for reproductive health, malaria, STIs, pneumonia, and diarrhea. This project applied ingredients based costing for labor, supplies, transport, and overhead. Data were gathered seven during key informant interviews with staff in the central Yangon office, examination of 3 years of payroll data, examination of a time motion study conducted by PSI, and spreadsheets recording the costs of acquiring and transporting supplies. In 2009 PSI Myanmar's social franchise devoted $2.02 million towards a 94% reduction in commodity prices offered to its network of over 1700 primary care providers. These providers retained 1/3 of the subsidy as revenue and passed along the other 2/3 to their patients in the course of offering subsidized care for 1.5 million health episodes. In addition, PSI Myanmar devoted $2.09 million to support a team of franchise officers who conducted quality assurance for the private providers overseeing service quality and to distributing medical commodities. In Myanmar, the social franchise operated by PSI spends roughly $1.00 in quality management and retailing for every $1.00 spent subsidizing medical commodities. Some services are free, but patients also pay fees for other lines of service. Overall patients contribute 1/6 as much as PSI does. Unlike other NGO's, health services in social franchises like PSI are not all free to the patients, nor are the discounts uniformly applied. Discounts and subsidies evolve in response to public health concerns, market demand, providers' cost structures as well as strategic objectives in maintaining the network and its portfolio of services.

Minimisation of a heat exchanger networks' cost over its lifetime

International Nuclear Information System (INIS)

Nemet, Andreja; Klemeš, Jiří Jaromír; Kravanja, Zdravko

2012-01-01

The optimal design of heat exchanger networks (HENs) has a great influence on the profitability of a plant. The optimisation is based on trade-offs between investment and operational cost. The full lifetime of the HEN and future utility prices have to be considered rather than optimising HEN on a yearly basis using current utility prices. Single-period optimisation and synthesis models for HENs reflect current utility prices only. These prices can fluctuate rather quickly and the optimal solution may be very different from a year to year. Deterministic and stochastic multi-period mixed-integer nonlinear programming (MINLP) models for HEN synthesis have been developed to account for future price projections, where the utility cost coefficients are forecasted for the lifetime of the process. An optimal design is then determined for each projection and these designs are compared against a design with fixed current prices by applying the Incremental Net Present Value and other economic measures. In case studies the difference between utility consumption, using previous optimisation methods and new, were significant; e.g. in Case Study 2 the utility savings were 18.4% for hot and 32.6% for cold utility yielding an increase of the Net Present Value (NPV) by 7.8%. Highlights: ► Optimisation using forecasted utility prices can lead to higher energy recovery. ► Incremental Net Present Value when using future versus current prices is positive. ► The reduction of utilities increases with the process lifetime. ► Developed multi-period MINLP models for HEN account for future utility prices.

Probabilistic costing of transmission services

International Nuclear Information System (INIS)

Wijayatunga, P.D.C.

1992-01-01

Costing of transmission services of electrical utilities is required for transactions involving the transport of energy over a power network. The calculation of these costs based on Short Run Marginal Costing (SRMC) is preferred over other methods proposed in the literature due to its economic efficiency. In the research work discussed here, the concept of probabilistic costing of use-of-system based on SRMC which emerges as a consequence of the uncertainties in a power system is introduced using two different approaches. The first approach, based on the Monte Carlo method, generates a large number of possible system states by simulating random variables in the system using pseudo random number generators. A second approach to probabilistic use-of-system costing is proposed based on numerical convolution and multi-area representation of the transmission network. (UK)

12 CFR 714.5 - What is required if you rely on an estimated residual value greater than 25% of the original cost...

Science.gov (United States)

2010-01-01

... 12 Banks and Banking 6 2010-01-01 2010-01-01 false What is required if you rely on an estimated residual value greater than 25% of the original cost of the leased property? 714.5 Section 714.5 Banks and Banking NATIONAL CREDIT UNION ADMINISTRATION REGULATIONS AFFECTING CREDIT UNIONS LEASING § 714.5 What is...

Narrow Networks On The Health Insurance Marketplaces: Prevalence, Pricing, And The Cost Of Network Breadth.

Science.gov (United States)

Dafny, Leemore S; Hendel, Igal; Marone, Victoria; Ody, Christopher

2017-09-01

Anecdotal reports and systematic research highlight the prevalence of narrow-network plans on the Affordable Care Act's health insurance Marketplaces. At the same time, Marketplace premiums in the period 2014-16 were much lower than projected by the Congressional Budget Office in 2009. Using detailed data on the breadth of both hospital and physician networks, we studied the prevalence of narrow networks and quantified the association between network breadth and premiums. Controlling for many potentially confounding factors, we found that a plan with narrow physician and hospital networks was 16 percent cheaper than a plan with broad networks for both, and that narrowing the breadth of just one type of network was associated with a 6-9 percent decrease in premiums. Narrow-network plans also have a sizable impact on federal outlays, as they depress the premium of the second-lowest-price silver plan, to which subsidy amounts are linked. Holding all else constant, we estimate that federal subsidies would have been 10.8 percent higher in 2014 had Marketplaces required all plans to offer broad provider networks. Narrow networks are a promising source of potential savings for other segments of the commercial insurance market. Project HOPE—The People-to-People Health Foundation, Inc.

The evolution of cooperation on geographical networks

Science.gov (United States)

Li, Yixiao; Wang, Yi; Sheng, Jichuan

2017-11-01

We study evolutionary public goods game on geographical networks, i.e., complex networks which are located on a geographical plane. The geographical feature effects in two ways: In one way, the geographically-induced network structure influences the overall evolutionary dynamics, and, in the other way, the geographical length of an edge influences the cost when the two players at the two ends interact. For the latter effect, we design a new cost function of cooperators, which simply assumes that the longer the distance between two players, the higher cost the cooperator(s) of them have to pay. In this study, network substrates are generated by a previous spatial network model with a cost-benefit parameter controlling the network topology. Our simulations show that the greatest promotion of cooperation is achieved in the intermediate regime of the parameter, in which empirical estimates of various railway networks fall. Further, we investigate how the distribution of edges' geographical costs influences the evolutionary dynamics and consider three patterns of the distribution: an approximately-equal distribution, a diverse distribution, and a polarized distribution. For normal geographical networks which are generated using intermediate values of the cost-benefit parameter, a diverse distribution hinders the evolution of cooperation, whereas a polarized distribution lowers the threshold value of the amplification factor for cooperation in public goods game. These results are helpful for understanding the evolution of cooperation on real-world geographical networks.

A Novel Model of Conforming Delaunay Triangulation for Sensor Network Configuration

Directory of Open Access Journals (Sweden)

Yan Ma

2015-01-01

Full Text Available Delaunay refinement is a technique for generating unstructured meshes of triangles for sensor network configuration engineering practice. A new method for solving Delaunay triangulation problem is proposed in this paper, which is called endpoint triangle’s circumcircle model (ETCM. As compared with the original fractional node refinement algorithms, the proposed algorithm can get well refinement stability with least time cost. Simulations are performed under five aspects including refinement stability, the number of additional nodes, time cost, mesh quality after intruding additional nodes, and the aspect ratio improved by single additional node. All experimental results show the advantages of the proposed algorithm as compared with the existing algorithms and confirm the algorithm analysis sufficiently.

On the origin of distribution patterns of motifs in biological networks

Directory of Open Access Journals (Sweden)

Lesk Arthur M

2008-08-01

Full Text Available Abstract Background Inventories of small subgraphs in biological networks have identified commonly-recurring patterns, called motifs. The inference that these motifs have been selected for function rests on the idea that their occurrences are significantly more frequent than random. Results Our analysis of several large biological networks suggests, in contrast, that the frequencies of appearance of common subgraphs are similar in natural and corresponding random networks. Conclusion Indeed, certain topological features of biological networks give rise naturally to the common appearance of the motifs. We therefore question whether frequencies of occurrences are reasonable evidence that the structures of motifs have been selected for their functional contribution to the operation of networks.

Incorporating Low-Cost Seismometers into the Central Weather Bureau Seismic Network for Earthquake Early Warning in Taiwan

Directory of Open Access Journals (Sweden)

Da-Yi Chen

2015-01-01

Full Text Available A dense seismic network can increase Earthquake Early Warning (EEW system capability to estimate earthquake information with higher accuracy. It is also critical for generating fast, robust earthquake alarms before strong-ground shaking hits the target area. However, building a dense seismic network via traditional seismometers is too expensive and may not be practical. Using low-cost Micro-Electro Mechanical System (MEMS accelerometers is a potential solution to quickly deploy a large number of sensors around the monitored region. An EEW system constructed using a dense seismic network with 543 MEMS sensors in Taiwan is presented. The system also incorporates the official seismic network of _ Central Weather Bureau (CWB. The real-time data streams generated by the two networks are integrated using the Earthworm software. This paper illustrates the methods used by the integrated system for estimating earthquake information and evaluates the system performance. We applied the Earthworm picker for the seismograms recorded by the MEMS sensors (Chen et al. 2015 following new picking constraints to accurately detect P-wave arrivals and use a new regression equation for estimating earthquake magnitudes. An off-line test was implemented using 46 earthquakes with magnitudes ranging from ML 4.5 - 6.5 to calibrate the system. The experimental results show that the integrated system has stable source parameter results and issues alarms much faster than the current system run by the CWB seismic network (CWBSN.

SONG China project - participating in the global network

Science.gov (United States)

Deng, Licai; Xin, Yu; Zhang, Xiaobin; Li, Yan; Jiang, Xiaojun; Wang, Guomin; Wang, Kun; Zhou, Jilin; Yan, Zhengzhou; Luo, Zhiquan

2013-01-01

SONG (Stellar Observations Network Goup) is a low-cost ground based international collaboration aimed at two cutting edge problems in contemporary astrophysics in the time-domain: 1) Direct diagnostics of the internal structure of stars and 2) looking for and studying extra solar planets, possibly in the habitable zone. The general plan is to set up a network of 1m telescopes uniformly distributed in geographic latitude (in both hemispheres). China jointed the collaboration (initiated by Danish astronomers) at the very beginning. In addition to SONG's original plan (http://song.phys.au.dk), the Chinese team proposed a parallel photometry subnet work in the northern hemisphere, namely 50BiN (50cm Binocular Network, previously known as mini-SONG), to enable a large field photometric capability for the network, therefore maximising the potential of the network platform. The network will be able to produce nearly continuous time series observations of a number of selected objects with high resolution spectroscopy (SONG) and accurate photometry (50BiN), and to produce ultra-high accuracy photometry in dense field to look for micro-lensing events caused by planetary systems. This project has great synergy with Chinese Astronomical activities in Antarctica (Dome A), and other similar networks (e.g. LCOGT). The plan and current status of the project are overviewed in this poster.

Marginal pricing of transmission services: An analysis of cost recovery

Energy Technology Data Exchange (ETDEWEB)

Perez-Arriaga, I.J.; Rubio, F.J. [Univ. Pontificia Comillas, Madrid (Spain); Puerta, J.F.; Arceluz, J.; Marin, J. [IBERDROLA, Bilbao (Spain). Unidad de Planificacion Estrategica

1995-02-01

This paper presents an in-depth analysis of network revenues computed with marginal pricing, and in particular it investigates the reasons why marginal prices fail to recover the total incurred network costs in actual power systems. The basic theoretical results are presented and the major causes of the mismatch between network costs and marginal revenues are identified and illustrated with numerical examples, some tutorial and others of realistic size. The regulatory implications of marginal network pricing in the context of competitive electricity markets are analyzed, and suggestions are provided for the meaningful allocation of the costs of the network among its users.

Marginal pricing of transmission services: An analysis of cost recovery

International Nuclear Information System (INIS)

Perez-Arriaga, I.J.; Rubio, F.J.; Puerta, J.F.; Arceluz, J.; Marin, J.

1995-01-01

This paper presents an in-depth analysis of network revenues computed with marginal pricing, and in particular it investigates the reasons why marginal prices fail to recover the total incurred network costs in actual power systems. The basic theoretical results are presented and the major causes of the mismatch between network costs and marginal revenues are identified and illustrated with numerical examples, some tutorial and others of realistic size. The regulatory implications of marginal network pricing in the context of competitive electricity markets are analyzed, and suggestions are provided for the meaningful allocation of the costs of the network among its users

Search for minimal paths in modified networks

International Nuclear Information System (INIS)

Yeh, W.-C.

2002-01-01

The problem of searching for all minimal paths (MPs) in a network obtained by modifying the original network, e.g. for network expansion or reinforcement, is discussed and solved in this study. The existing best-known method to solve this problem was a straightforward approach. It needed extensive comparison and verification, and failed to solve some special but important cases. Therefore, a more efficient, intuitive and generalized method to search for all MPs without an extensive research procedure is proposed. In this presentation, first we develop an intuitive algorithm based upon the reformation of all MPs in the original network to search for all MPs in a modified network. Next, the computational complexity of the proposed algorithm is analyzed and compared with the existing methods. Finally, examples illustrate how all MPs are generated in a modified network based upon the reformation of all of the MPs in the corresponding original network

A Network-Based Impact Measure for Propagated Losses in a Supply Chain Network Consisting of Resilient Components

Directory of Open Access Journals (Sweden)

Jesus Felix Bayta Valenzuela

2018-01-01

Full Text Available The topology of a supply chain network affects the impacts of disruptions in it. We formulate a network-based measure of the impact of a disruption loss in a supply chain propagating downstream from an originating node. The measure takes into account the loss profile of the originating node, the structure of the supply network, and the resilience of the network components. We obtain an analytical expression for the impact measure under a beta-distributed initial loss (generalizable to any continuous distribution supported on the interval 0,1, under a breakthrough scenario (in which a fraction of the initial production loss reaches a focal company downstream as opposed to containment upstream or at the originating point. Furthermore, we obtain a closed-form solution for a supply chain network with a k-ary tree topology; a numerical study is performed for a scale-free network and a random network. Our proposed approach enables the evaluation of potential losses for a focal company considering its supply chain network structure, which may help the company to plan or redesign a robust and resilient network in response to different types of disruptions.

The brain's default network: origins and implications for the study of psychosis.

Science.gov (United States)

Buckner, Randy L

2013-09-01

The brain's default network is a set of regions that is spontaneously active during passive moments. The network is also active during directed tasks that require participants to remember past events or imagine upcoming events. One hypothesis is that the network facilitates construction of mental models (simulations) that can be used adaptively in many contexts. Extensive research has considered whether disruption of the default network may contribute to disease. While an intriguing possibility, a specific challenge to this notion is the fact that it is difficult to accurately measure the default network in patients where confounds of head motion and compliance are prominent. Nonetheless, some intriguing recent findings suggest that dysfunctional interactions between front-oparietal control systems and the default network contribute to psychosis. Psychosis may be a network disturbance that manifests as disordered thought partly because it disrupts the fragile balance between the default network and competing brain systems.

Communication Network Architectures Based on Ethernet Passive Optical Network for Offshore Wind Power Farms

Directory of Open Access Journals (Sweden)

Mohamed A. Ahmed

2016-03-01

Full Text Available Nowadays, with large-scale offshore wind power farms (WPFs becoming a reality, more efforts are needed to maintain a reliable communication network for WPF monitoring. Deployment topologies, redundancy, and network availability are the main items to enhance the communication reliability between wind turbines (WTs and control centers. Traditional communication networks for monitoring and control (i.e., supervisory control and data acquisition (SCADA systems using switched gigabit Ethernet will not be sufficient for the huge amount of data passing through the network. In this paper, the optical power budget, optical path loss, reliability, and network cost of the proposed Ethernet Passive Optical Network (EPON-based communication network for small-size offshore WPFs have been evaluated for five different network architectures. The proposed network model consists of an optical network unit device (ONU deployed on the WT side for collecting data from different internal networks. All ONUs from different WTs are connected to a central optical line terminal (OLT, placed in the control center. There are no active electronic elements used between the ONUs and the OLT, which reduces the costs and complexity of maintenance and deployment. As fiber access networks without any protection are characterized by poor reliability, three different protection schemes have been configured, explained, and discussed. Considering the cost of network components, the total implementation expense of different architectures with, or without, protection have been calculated and compared. The proposed network model can significantly contribute to the communication network architecture for next generation WPFs.

Violence originated from Facebook: A case study in Bangladesh

OpenAIRE

Minar, Matiur Rahman; Naher, Jibon

2018-01-01

Facebook as in social network is a great innovation of modern times. Among all social networking sites, Facebook is the most popular social network all over the world. Bangladesh is no exception. People use Facebook for various reasons e.g. social networking and communication, online shopping and business, knowledge and experience sharing etc. However, some recent incidents in Bangladesh, originated from or based on Facebook activities, led to arson and violence. Social network i.e. Facebook ...

A Nonlinear Multiobjective Bilevel Model for Minimum Cost Network Flow Problem in a Large-Scale Construction Project

Directory of Open Access Journals (Sweden)

Jiuping Xu

2012-01-01

Full Text Available The aim of this study is to deal with a minimum cost network flow problem (MCNFP in a large-scale construction project using a nonlinear multiobjective bilevel model with birandom variables. The main target of the upper level is to minimize both direct and transportation time costs. The target of the lower level is to minimize transportation costs. After an analysis of the birandom variables, an expectation multiobjective bilevel programming model with chance constraints is formulated to incorporate decision makers’ preferences. To solve the identified special conditions, an equivalent crisp model is proposed with an additional multiobjective bilevel particle swarm optimization (MOBLPSO developed to solve the model. The Shuibuya Hydropower Project is used as a real-world example to verify the proposed approach. Results and analysis are presented to highlight the performances of the MOBLPSO, which is very effective and efficient compared to a genetic algorithm and a simulated annealing algorithm.

Cloud Radio Access Network architecture. Towards 5G mobile networks

DEFF Research Database (Denmark)

Checko, Aleksandra

Cloud Radio Access Network (C-RAN) is a novel mobile network architecture which can address a number of challenges that mobile operators face while trying to support ever-growing end-users’ needs towards 5th generation of mobile networks (5G). The main idea behind C-RAN is to split the base...... stations into radio and baseband parts, and pool the Baseband Units (BBUs) from multiple base stations into a centralized and virtualized BBU Pool. This gives a number of benefits in terms of cost and capacity. However, the challenge is then to find an optimal functionality splitting point as well...... as to design the socalled fronthaul network, interconnecting those parts. This thesis focuses on quantifying those benefits and proposing a flexible and capacity-optimized fronthaul network. It is shown that a C-RAN with a functional split resulting in a variable bit rate on the fronthaul links brings cost...

The Role of Trust in Costly Network Formation

NARCIS (Netherlands)

Gilles, R.P.; Sarangi, S.

2003-01-01

We consider game theoretic models of social network formation.In this paper we limit our investigation to game theoretic models of network formation that are based on individual actions only.Our approach is based on three simple and realistic principles: (1) Link formation is a binary process of

Computer network time synchronization the network time protocol

CERN Document Server

Mills, David L

2006-01-01

What started with the sundial has, thus far, been refined to a level of precision based on atomic resonance: Time. Our obsession with time is evident in this continued scaling down to nanosecond resolution and beyond. But this obsession is not without warrant. Precision and time synchronization are critical in many applications, such as air traffic control and stock trading, and pose complex and important challenges in modern information networks.Penned by David L. Mills, the original developer of the Network Time Protocol (NTP), Computer Network Time Synchronization: The Network Time Protocol

WDM Core Networks : regenerator placement and green networking

OpenAIRE

Youssef , Mayssa

2011-01-01

As Operators strive today to optimize their networks, considerations of cost, availability, eco-sustainability, and quality of service are beginning to converge. Solutions that reduce capital and operational expenditures not only save money, but also tend to reduce the environmental impact. In "opaque" networks, optical signals undergo expensive electrical regeneration systematically at each node. In "transparent" networks, signal quality deteriorates due to the accumulation of physical impai...

An original tool for checking energy performance and certification of buildings by means of Artificial Neural Networks

International Nuclear Information System (INIS)

Buratti, C.; Barbanera, M.; Palladino, D.

2014-01-01

Highlights: • ANN used as a tool for evaluating energy performance of buildings. • Training, validation, and testing of Neural Network with real energy certificates data. • Global energy performance index was chosen as a target of ANN. • A good correlation and a minimum error was found with certificates data. • A new energy index was defined in order to check the energy certificates. - Abstract: The Energy Performance Buildings Directive (EPBD) was issued to provide a common strategy for all European countries and to implement several actions for improving energy efficiency of buildings, responsible for 40% of energy consumption. Energy Performance Certificates are provided as a tool to evaluate the energy performance of buildings; however, costly and time-consuming controls are necessary to verify the accuracy of the set and declared data. Useful tools could be the Artificial Neural Networks (ANN), whereby it is possible to estimate the energy consumptions from specific parameters, to evaluate the accuracy of data in the energy certificates, and to identify the certificates needing accurate control. In this study, an Artificial Neural Network was developed based on approximately 6500 energy certificates (2700 are self-declaration) received by the Umbria Region (central Italy), in order to evaluate the global energy consumption of buildings from several and specific parameters reported in certificates. Data was checked in compliance with energy standards and only the correct certificates were used to train the Neural Network. The implemented Neural Network was tested with database data and a good correlation was found; in particular the energy performance calculated with the Neural Network presents an error greater than 15 kW h/m 2 year with respect to the real value of global energy performance index in only 3.6% of cases. Finally, a Neural Energy Performance Index (N.E.P.I.) was defined, in order to verify the accuracy of the energy certificates; the

Assessing the Performance of a Network of Low Cost Particulate Matter Sensors Deployed in Sacramento, California

Science.gov (United States)

Mukherjee, A. D.; Brown, S. G.; McCarthy, M. C.

2017-12-01

A new generation of low cost air quality sensors have the potential to provide valuable information on the spatial-temporal variability of air pollution - if the measurements have sufficient quality. This study examined the performance of a particulate matter sensor model, the AirBeam (HabitatMap Inc., Brooklyn, NY), over a three month period in the urban environment of Sacramento, California. Nineteen AirBeam sensors were deployed at a regulatory air monitoring site collocated with meteorology measurements and as a local network over an 80 km2 domain in Sacramento, CA. This study presents the methodology to evaluate the precision, accuracy, and reliability of the sensors over a range of meteorological and aerosol conditions. The sensors demonstrated a robust degree of precision during collocated measurement periods (R2 = 0.98 - 0.99) and a moderate degree of correlation against a Beta Attenuation Monitor PM2.5 monitor (R2 0.6). A normalization correction is applied during the study period so that each AirBeam sensor in the network reports a comparable value. The role of the meteorological environment on the accuracy of the sensor measurements is investigated, along with the possibility of improving the measurements through a meteorology weighted correction. The data quality of the network of sensors is examined, and the spatial variability of particulate matter through the study domain derived from the sensor network is presented.

Topological patterns in street networks of self-organized urban settlements

Science.gov (United States)

Buhl, J.; Gautrais, J.; Reeves, N.; Solé, R. V.; Valverde, S.; Kuntz, P.; Theraulaz, G.

2006-02-01

Many urban settlements result from a spatially distributed, decentralized building process. Here we analyze the topological patterns of organization of a large collection of such settlements using the approach of complex networks. The global efficiency (based on the inverse of shortest-path lengths), robustness to disconnections and cost (in terms of length) of these graphs is studied and their possible origins analyzed. A wide range of patterns is found, from tree-like settlements (highly vulnerable to random failures) to meshed urban patterns. The latter are shown to be more robust and efficient.

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.

Floyd-A∗ Algorithm Solving the Least-Time Itinerary Planning Problem in Urban Scheduled Public Transport Network

Directory of Open Access Journals (Sweden)

Yu Zhang

2014-01-01

Full Text Available We consider an ad hoc Floyd-A∗ algorithm to determine the a priori least-time itinerary from an origin to a destination given an initial time in an urban scheduled public transport (USPT network. The network is bimodal (i.e., USPT lines and walking and time dependent. The modified USPT network model results in more reasonable itinerary results. An itinerary is connected through a sequence of time-label arcs. The proposed Floyd-A∗ algorithm is composed of two procedures designated as Itinerary Finder and Cost Estimator. The A∗-based Itinerary Finder determines the time-dependent, least-time itinerary in real time, aided by the heuristic information precomputed by the Floyd-based Cost Estimator, where a strategy is formed to preestimate the time-dependent arc travel time as an associated static lower bound. The Floyd-A∗ algorithm is proven to guarantee optimality in theory and, demonstrated through a real-world example in Shenyang City USPT network to be more efficient than previous procedures. The computational experiments also reveal the time-dependent nature of the least-time itinerary. In the premise that lines run punctually, “just boarding” and “just missing” cases are identified.

Coevolutionary modeling in network formation

KAUST Repository

Al-Shyoukh, Ibrahim

2014-12-03

Network coevolution, the process of network topology evolution in feedback with dynamical processes over the network nodes, is a common feature of many engineered and natural networks. In such settings, the change in network topology occurs at a comparable time scale to nodal dynamics. Coevolutionary modeling offers the possibility to better understand how and why network structures emerge. For example, social networks can exhibit a variety of structures, ranging from almost uniform to scale-free degree distributions. While current models of network formation can reproduce these structures, coevolutionary modeling can offer a better understanding of the underlying dynamics. This paper presents an overview of recent work on coevolutionary models of network formation, with an emphasis on the following three settings: (i) dynamic flow of benefits and costs, (ii) transient link establishment costs, and (iii) latent preferential attachment.

Coevolutionary modeling in network formation

KAUST Repository

Al-Shyoukh, Ibrahim; Chasparis, Georgios; Shamma, Jeff S.

2014-01-01

Network coevolution, the process of network topology evolution in feedback with dynamical processes over the network nodes, is a common feature of many engineered and natural networks. In such settings, the change in network topology occurs at a comparable time scale to nodal dynamics. Coevolutionary modeling offers the possibility to better understand how and why network structures emerge. For example, social networks can exhibit a variety of structures, ranging from almost uniform to scale-free degree distributions. While current models of network formation can reproduce these structures, coevolutionary modeling can offer a better understanding of the underlying dynamics. This paper presents an overview of recent work on coevolutionary models of network formation, with an emphasis on the following three settings: (i) dynamic flow of benefits and costs, (ii) transient link establishment costs, and (iii) latent preferential attachment.

Control of a hybrid compensator in a power network by an artificial neural network

Directory of Open Access Journals (Sweden)

I. S. Shaw

1998-07-01

Full Text Available Increased interest in the elimination of distortion in electrical power networks has led to the development of various compensator topologies. The increasing cost of electrical energy necessitates the cost-effective operation of any of these topologies. This paper considers the development of an artificial neural network based controller, trained by means of the backpropagation method, that ensures the cost-effective operation of the hybrid compensator consisting of various converters and filters.

Cost sharing in production situations and network exploitation

NARCIS (Netherlands)

Koster, M.A.L.

1999-01-01

In many real-life situations where individuals work together in a joint project, joint costs (or profits) occur which have to be shared. The central problem of cost sharing is the allocation of costs in a 'just' way among the participants. Examples are numerous and range from setting fees for the

Network cosmology.

Science.gov (United States)

Krioukov, Dmitri; Kitsak, Maksim; Sinkovits, Robert S; Rideout, David; Meyer, David; Boguñá, Marián

2012-01-01

Prediction and control of the dynamics of complex networks is a central problem in network science. Structural and dynamical similarities of different real networks suggest that some universal laws might accurately describe the dynamics of these networks, albeit the nature and common origin of such laws remain elusive. Here we show that the causal network representing the large-scale structure of spacetime in our accelerating universe is a power-law graph with strong clustering, similar to many complex networks such as the Internet, social, or biological networks. We prove that this structural similarity is a consequence of the asymptotic equivalence between the large-scale growth dynamics of complex networks and causal networks. This equivalence suggests that unexpectedly similar laws govern the dynamics of complex networks and spacetime in the universe, with implications to network science and cosmology.

The Network effects of Railway Investments

DEFF Research Database (Denmark)

Hansen, Sten; Landex, Alex; Kaas, Anders H.

2006-01-01

Network effects is when a change at one place in the railway network results in changes elsewhere in the network – maybe even far away from the original change. Railway investments have network effects, and therefore, this paper describes the network effects and how these network effects can...

Adaptive Suspicious Prevention for Defending DoS Attacks in SDN-Based Convergent Networks.

Science.gov (United States)

Dao, Nhu-Ngoc; Kim, Joongheon; Park, Minho; Cho, Sungrae

2016-01-01

The convergent communication network will play an important role as a single platform to unify heterogeneous networks and integrate emerging technologies and existing legacy networks. Although there have been proposed many feasible solutions, they could not become convergent frameworks since they mainly focused on converting functions between various protocols and interfaces in edge networks, and handling functions for multiple services in core networks, e.g., the Multi-protocol Label Switching (MPLS) technique. Software-defined networking (SDN), on the other hand, is expected to be the ideal future for the convergent network since it can provide a controllable, dynamic, and cost-effective network. However, SDN has an original structural vulnerability behind a lot of advantages, which is the centralized control plane. As the brains of the network, a controller manages the whole network, which is attractive to attackers. In this context, we proposes a novel solution called adaptive suspicious prevention (ASP) mechanism to protect the controller from the Denial of Service (DoS) attacks that could incapacitate an SDN. The ASP is integrated with OpenFlow protocol to detect and prevent DoS attacks effectively. Our comprehensive experimental results show that the ASP enhances the resilience of an SDN network against DoS attacks by up to 38%.

Synchronization on effective networks

International Nuclear Information System (INIS)

Zhou Tao; Zhao Ming; Zhou Changsong

2010-01-01

The study of network synchronization has attracted increasing attentionrecently. In this paper, we strictly define a class of networks, namely effective networks, which are synchronizable and orientable networks. We can prove that all the effective networks with the same size have the same spectra, and are of the best synchronizability according to the master stability analysis. However, it is found that the synchronization time for different effective networks can be quite different. Further analysis shows that the key ingredient affecting the synchronization time is the maximal depth of an effective network: the larger depth results in a longer synchronization time. The secondary factor is the number of links. The increasing number of links connecting nodes in the same layer (horizontal links) will lead to longer synchronization time, whereas the increasing number of links connecting nodes in neighboring layers (vertical links) will accelerate the synchronization. Our analysis of the relationship between the structure and synchronization properties of the original and effective networks shows that the purely directed effective network can provide an approximation of the original weighted network with normalized input strength. Our findings provide insights into the roles of depth, horizontal and vertical links in the synchronizing process, and suggest that the spectral analysis is helpful yet insufficient for the comprehensive understanding of network synchronization.

Synchronization on effective networks

Energy Technology Data Exchange (ETDEWEB)

Zhou Tao [Web Sciences Center, University of Electronic Science and Technology of China, Chengdu 610054 (China); Zhao Ming [Department of Modern Physics, University of Science and Technology of China, Hefei 230026 (China); Zhou Changsong, E-mail: cszhou@hkbu.edu.h [Department of Physics, Hong Kong Baptist University, Kowloon Tong (Hong Kong)

2010-04-15

The study of network synchronization has attracted increasing attentionrecently. In this paper, we strictly define a class of networks, namely effective networks, which are synchronizable and orientable networks. We can prove that all the effective networks with the same size have the same spectra, and are of the best synchronizability according to the master stability analysis. However, it is found that the synchronization time for different effective networks can be quite different. Further analysis shows that the key ingredient affecting the synchronization time is the maximal depth of an effective network: the larger depth results in a longer synchronization time. The secondary factor is the number of links. The increasing number of links connecting nodes in the same layer (horizontal links) will lead to longer synchronization time, whereas the increasing number of links connecting nodes in neighboring layers (vertical links) will accelerate the synchronization. Our analysis of the relationship between the structure and synchronization properties of the original and effective networks shows that the purely directed effective network can provide an approximation of the original weighted network with normalized input strength. Our findings provide insights into the roles of depth, horizontal and vertical links in the synchronizing process, and suggest that the spectral analysis is helpful yet insufficient for the comprehensive understanding of network synchronization.

MPC control of water supply networks

DEFF Research Database (Denmark)

Baunsgaard, Kenneth Marx Hoe; Ravn, Ole; Kallesoe, Carsten Skovmose

2016-01-01

This paper investigates the modelling and predictive control of a drinking water supply network with the aim of minimising the energy and economic cost. A model predictive controller, MPC, is applied to a nonlinear model of a drinking water network that follows certain constraints to maintain......, controlling the drinking water supply network with the MPC showed reduction of the energy and the economic cost of running the system. This has been achieved by minimising actuator control effort and by shifting the actuator use towards the night time, where energy prices are lower. Along with energy cost...... consumer pressure desire. A model predictive controller, MPC, is based on a simple model that models the main characteristics of a water distribution network, optimizes a desired cost minimisation, and keeps the system inside specified constraints. In comparison to a logic (on/off) control design...

A distributed network of low-cost continuous reading sensors to measure spatiotemporal variations of PM2.5 in Xi'an, China

International Nuclear Information System (INIS)

Gao, Meiling; Cao, Junji; Seto, Edmund

2015-01-01

Fine particulate matter (PM2.5) is a growing public health concern especially in industrializing countries but existing monitoring networks are unable to properly characterize human exposures due to low resolution spatiotemporal data. Low-cost portable monitors can supplement existing networks in both developed and industrializing regions to increase density of sites and data. This study tests the performance of a low-cost sensor in high concentration urban environments. Seven Portable University of Washington Particle (PUWP) monitors were calibrated with optical and gravimetric PM2.5 reference monitors in Xi'an, China in December 2013. Pairwise correlations between the raw PUWP and the reference monitors were high (R 2  = 0.86–0.89). PUWP monitors were also simultaneously deployed at eight sites across Xi'an alongside gravimetric PM2.5 monitors (R 2  = 0.53). The PUWP monitors were able to identify the High-technology Zone site as a potential PM2.5 hotspot with sustained high concentrations compared to the city average throughout the day. - Highlights: • A $15 portable PM sensor demonstrated high correlations with reference monitors. • The sensor can be deployed in high PM2.5 urban environments. • The sensor can improve spatiotemporal resolution of data from existing monitoring networks. - This reliable low-cost portable PM sensor could help improve monitoring and management of urban air pollution to help protect public health in both developed and developing areas

On the cost/delay tradeoff of wireless delay tolerant geographic routing

OpenAIRE

Tasiopoulos, Argyrios; Tsiaras, Christos; Toumpis, Stavros

2012-01-01

In Delay Tolerant Networks (DTNs), there is a fundamental tradeoff between the aggregate transport cost of a packet and the delay in its delivery. We study this tradeoff in the context of geographical routing in wireless DTNs.We ?rst specify the optimal cost/delay tradeoff, i.e., the tradeoff under optimal network operation, using a dynamic network construction termed the Cost/Delay Evolving Graph (C/DEG) and the Optimal Cost/Delay Curve (OC/DC), a function that gives the minimum possible agg...

Requirements of the integration of renewable energy into network charge regulation. Proposals for the further development of the network charge system. Final report

International Nuclear Information System (INIS)

Friedrichsen, Nele; Klobasa, Marian; Marwitz, Simon; Hilpert, Johannes; Sailer, Frank

2016-01-01

In this project we analyzed options to advance the network tariff system to support the German energy transition. A power system with high shares of renewables, requires more flexibility of supply and demand than the traditional system based on centralized, fossil power plants. Further, the power networks need to be adjusted and expanded. The transformation should aim at system efficiency i.e. look at both generation and network development. Network tariffs allocate the network cost towards network users. They also should provide incentives, e.g. to reduce peak load in periods of network congestion. Inappropriate network tariffs can hinder the provision of flexibility and thereby become a barrier towards system integration of renewable. Against this background, this report presents a systematic review of the German network tariff system and a discussion of several options to adapt the network tarif system in order to support the energy transition. The following aspects are analyzed: An adjustment of the privileges for industrial users to increase potential network benefits and reduce barriers towards a more market oriented behaviour. The payments for avoided network charges to distributed generation, that do not reflect cost reality in distribution networks anymore. Uniform transmission network tariffs as an option for a more appropriate allocation of cost associated with the energy transition. Increased standing fees in low voltage networks as an option to increase the cost-contribution of users with self-generation to network financing. Generator tariffs, to allocate a share of network cost to generators and provide incentives for network oriented location choice and/or feed-in.

Marginal costs for road maintenance and operation - a cost function approach

OpenAIRE

Haraldsson, Mattias

2007-01-01

Using observational data covering the whole Swedish national road network for the period 1998-2002, this paper estimates a set of maintenance and operation cost functions. It is found that costs for all operation and maintenance measures increase with traffic intensity, with two exceptions; total operation and winter operation measures are fixed cost activities. All other operation and maintenance measures have short run elasticities in the range 0.25-0.60. The impact of an additional vehicle...

Modification Propagation in Complex Networks

Science.gov (United States)

Mouronte, Mary Luz; Vargas, María Luisa; Moyano, Luis Gregorio; Algarra, Francisco Javier García; Del Pozo, Luis Salvador

To keep up with rapidly changing conditions, business systems and their associated networks are growing increasingly intricate as never before. By doing this, network management and operation costs not only rise, but are difficult even to measure. This fact must be regarded as a major constraint to system optimization initiatives, as well as a setback to derived economic benefits. In this work we introduce a simple model in order to estimate the relative cost associated to modification propagation in complex architectures. Our model can be used to anticipate costs caused by network evolution, as well as for planning and evaluating future architecture development while providing benefit optimization.

A Roadmap and Cost Implications of Establishing Comprehensive Cancer Care Using a Teleradiotherapy Network in a Group of Sub-Saharan African Countries With No Access to Radiation Therapy

Energy Technology Data Exchange (ETDEWEB)

Datta, Niloy R., E-mail: niloyranjan.datta@ksa.ch [Center for Radiation Oncology, KSA-KSB, Kantonsspital Aarau, Aarau (Switzerland); Heuser, Michael [Center for Radiation Oncology, KSA-KSB, Kantonsspital Aarau, Aarau (Switzerland); Bodis, Stephan [Center for Radiation Oncology, KSA-KSB, Kantonsspital Aarau, Aarau (Switzerland); Department of Radiation Oncology, University Hospital Zurich, Zurich (Switzerland)

2016-08-01

Purpose: To propose a roadmap and explore the cost implications of establishing a teleradiotherapy network to provide comprehensive cancer care and capacity building in countries without access to radiation therapy. Methods and Materials: Ten low-income sub-Saharan countries with no current radiation therapy facilities were evaluated. A basic/secondary radiation therapy center (SRTC) with 2 teletherapy, 1 brachytherapy, 1 simulator, and a treatment planning facility was envisaged at a cost of 5 million US dollars (USD 5M). This could be networked with 1 to 4 primary radiation therapy centers (PRTC) with 1 teletherapy unit, each costing USD 2M. The numbers of PRTCs and SRTCs for each country were computed on the basis of cancer incidence, assuming that a PRTC and SRTC could respectively treat 450 and 900 patients annually. Results: An estimated 71,215 patients in these countries will need radiation therapy in 2020. Stepwise establishment of a network with 99 PRTCs and 28 SRTCs would result in 155 teletherapy units and 96% access to radiation therapy. A total of 310 radiation oncologists, 155 medical physicists, and 465 radiation therapy technologists would be needed. Capacity building could be undertaken through telementoring by networking to various international institutions and professional societies. Total infrastructure costs would be approximately USD 860.88M, only 0.94% of the average annual gross domestic product of these 10 countries. A total of 1.04 million patients could receive radiation therapy during the 15-year lifespan of a teletherapy unit for an investment of USD 826.69 per patient. For the entire population of 218.32 million, this equates to USD 4.11 per inhabitant. Conclusion: A teleradiotherapy network could be a cost-contained innovative health care strategy to provide effective comprehensive cancer care through resource sharing and capacity building. The network could also be expanded to include other allied specialties. The proposal calls for

Neural Networks and Micromechanics

Science.gov (United States)

Kussul, Ernst; Baidyk, Tatiana; Wunsch, Donald C.

The title of the book, "Neural Networks and Micromechanics," seems artificial. However, the scientific and technological developments in recent decades demonstrate a very close connection between the two different areas of neural networks and micromechanics. The purpose of this book is to demonstrate this connection. Some artificial intelligence (AI) methods, including neural networks, could be used to improve automation system performance in manufacturing processes. However, the implementation of these AI methods within industry is rather slow because of the high cost of conducting experiments using conventional manufacturing and AI systems. To lower the cost, we have developed special micromechanical equipment that is similar to conventional mechanical equipment but of much smaller size and therefore of lower cost. This equipment could be used to evaluate different AI methods in an easy and inexpensive way. The proved methods could be transferred to industry through appropriate scaling. In this book, we describe the prototypes of low cost microequipment for manufacturing processes and the implementation of some AI methods to increase precision, such as computer vision systems based on neural networks for microdevice assembly and genetic algorithms for microequipment characterization and the increase of microequipment precision.

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....

The Dynamic Enterprise Network Composition Algorithm for Efficient Operation in Cloud Manufacturing

Directory of Open Access Journals (Sweden)

Gilseung Ahn

2016-11-01

Full Text Available As a service oriented and networked model, cloud manufacturing (CM has been proposed recently for solving a variety of manufacturing problems, including diverse requirements from customers. In CM, on-demand manufacturing services are provided by a temporary production network composed of several enterprises participating within an enterprise network. In other words, the production network is the main agent of production and a subset of an enterprise network. Therefore, it is essential to compose the enterprise network in a way that can respond to demands properly. A properly-composed enterprise network means the network can handle demands that arrive at the CM, with minimal costs, such as network composition and operation costs, such as participation contract costs, system maintenance costs, and so forth. Due to trade-offs among costs (e.g., contract cost and opportunity cost of production, it is a non-trivial problem to find the optimal network enterprise composition. In addition, this includes probabilistic constraints, such as forecasted demand. In this paper, we propose an algorithm, named the dynamic enterprise network composition algorithm (DENCA, based on a genetic algorithm to solve the enterprise network composition problem. A numerical simulation result is provided to demonstrate the performance of the proposed algorithm.

Setting up virtual private network

International Nuclear Information System (INIS)

Huang Hongmei; Zhang Chengjun

2003-01-01

Setting up virtual private network for business enterprise provides a low cost network foundation, increases enterprise's network function and enlarges its private scope. The text introduces virtual private network's principal, privileges and protocols that use in virtual private network. At last, this paper introduces several setting up virtual private network's technologies which based on LAN

Setting up virtual private network

International Nuclear Information System (INIS)

Huang Hongmei; Zhang Chengjun

2003-01-01

Setting up virtual private network for business enterprise provides a low cost network foundation, increases enterprise network function and enlarges its private scope. This text introduces virtual private network principal, privileges and protocols applied in virtual private network. At last, this paper introduces several setting up virtual private network technologies which is based on LAN

Analysis of Recurrent Analog Neural Networks

Directory of Open Access Journals (Sweden)

Z. Raida

1998-06-01

Full Text Available In this paper, an original rigorous analysis of recurrent analog neural networks, which are built from opamp neurons, is presented. The analysis, which comes from the approximate model of the operational amplifier, reveals causes of possible non-stable states and enables to determine convergence properties of the network. Results of the analysis are discussed in order to enable development of original robust and fast analog networks. In the analysis, the special attention is turned to the examination of the influence of real circuit elements and of the statistical parameters of processed signals to the parameters of the network.

Resolving epidemic network failures through differentiated repair times

DEFF Research Database (Denmark)

Fagertun, Anna Manolova; Ruepp, Sarah Renée; Manzano, Marc

2015-01-01

In this study, the authors investigate epidemic failure spreading in large-scale transport networks under generalisedmulti-protocol label switching control plane. By evaluating the effect of the epidemic failure spreading on the network,they design several strategies for cost-effective network pe...... assigninglower repair times among the network nodes. They believe that the event-driven simulation model can be highly beneficialfor network providers, since it could be used during the network planning process for facilitating cost-effective networksurvivability design.......In this study, the authors investigate epidemic failure spreading in large-scale transport networks under generalisedmulti-protocol label switching control plane. By evaluating the effect of the epidemic failure spreading on the network,they design several strategies for cost-effective network...... performance improvement via differentiated repair times. First, theyidentify the most vulnerable and the most strategic nodes in the network. Then, via extensive event-driven simulations theyshow that strategic placement of resources for improved failure recovery has better performance than randomly...

Phase transitions in Pareto optimal complex networks.

Science.gov (United States)

Seoane, Luís F; Solé, Ricard

2015-09-01

The organization of interactions in complex systems can be described by networks connecting different units. These graphs are useful representations of the local and global complexity of the underlying systems. The origin of their topological structure can be diverse, resulting from different mechanisms including multiplicative processes and optimization. In spatial networks or in graphs where cost constraints are at work, as it occurs in a plethora of situations from power grids to the wiring of neurons in the brain, optimization plays an important part in shaping their organization. In this paper we study network designs resulting from a Pareto optimization process, where different simultaneous constraints are the targets of selection. We analyze three variations on a problem, finding phase transitions of different kinds. Distinct phases are associated with different arrangements of the connections, but the need of drastic topological changes does not determine the presence or the nature of the phase transitions encountered. Instead, the functions under optimization do play a determinant role. This reinforces the view that phase transitions do not arise from intrinsic properties of a system alone, but from the interplay of that system with its external constraints.

Computer networks and advanced communications

International Nuclear Information System (INIS)

Koederitz, W.L.; Macon, B.S.

1992-01-01

One of the major methods for getting the most productivity and benefits from computer usage is networking. However, for those who are contemplating a change from stand-alone computers to a network system, the investigation of actual networks in use presents a paradox: network systems can be highly productive and beneficial; at the same time, these networks can create many complex, frustrating problems. The issue becomes a question of whether the benefits of networking are worth the extra effort and cost. In response to this issue, the authors review in this paper the implementation and management of an actual network in the LSU Petroleum Engineering Department. The network, which has been in operation for four years, is large and diverse (50 computers, 2 sites, PC's, UNIX RISC workstations, etc.). The benefits, costs, and method of operation of this network will be described, and an effort will be made to objectively weigh these elements from the point of view of the average computer user

COST Action TU1206 "SUB-URBAN - A European network to improve understanding and use of the ground beneath our cities"

Science.gov (United States)

Campbell, Diarmad; de Beer, Johannes; Lawrence, David; van der Meulen, Michiel; Mielby, Susie; Hay, David; Scanlon, Ray; Campenhout, Ignace; Taugs, Renate; Eriksson, Ingelov

2014-05-01

Sustainable urbanisation is the focus of SUB-URBAN, a European Cooperation in Science and Technology (COST) Action TU1206 - A European network to improve understanding and use of the ground beneath our cities. This aims to transform relationships between experts who develop urban subsurface geoscience knowledge - principally national Geological Survey Organisations (GSOs), and those who can most benefit from it - urban decision makers, planners, practitioners and the wider research community. Under COST's Transport and Urban Development Domain, SUB-URBAN has established a network of GSOs and other researchers in over 20 countries, to draw together and evaluate collective urban geoscience research in 3D/4D characterisation, prediction and visualisation. Knowledge exchange between researchers and City-partners within 'SUB-URBAN' is already facilitating new city-scale subsurface projects, and is developing a tool-box of good-practice guidance, decision-support tools, and cost-effective methodologies that are appropriate to local needs and circumstances. These are intended to act as catalysts in the transformation of relationships between geoscientists and urban decision-makers more generally. As a result, the importance of the urban sub-surface in the sustainable development of our cities will be better appreciated, and the conflicting demands currently placed on it will be acknowledged, and resolved appropriately. Existing city-scale 3D/4D model exemplars are being developed by partners in the UK (Glasgow, London), Germany (Hamburg) and France (Paris). These draw on extensive ground investigation (10s-100s of thousands of boreholes) and other data. Model linkage enables prediction of groundwater, heat, SuDS, and engineering properties. Combined subsurface and above-ground (CityGML, BIMs) models are in preparation. These models will provide valuable tools for more holistic urban planning; identifying subsurface opportunities and saving costs by reducing uncertainty in

Distributed Multi-Commodity Network Flow Algorithm for Energy Optimal Routing in Wireless Sensor Networks.

Directory of Open Access Journals (Sweden)

J. Trdlicka

2010-12-01

Full Text Available This work proposes a distributed algorithm for energy optimal routing in a wireless sensor network. The routing problem is described as a mathematical problem by the minimum-cost multi-commodity network flow problem. Due to the separability of the problem, we use the duality theorem to derive the distributed algorithm. The algorithm computes the energy optimal routing in the network without any central node or knowledge of the whole network structure. Each node only needs to know the flow which is supposed to send or receive and the costs and capacities of the neighboring links. An evaluation of the presented algorithm on benchmarks for the energy optimal data flow routing in sensor networks with up to 100 nodes is presented.

A Model for Shovel Capital Cost Estimation, Using a Hybrid Model of Multivariate Regression and Neural Networks

Directory of Open Access Journals (Sweden)

Abdolreza Yazdani-Chamzini

2017-12-01

Full Text Available Cost estimation is an essential issue in feasibility studies in civil engineering. Many different methods can be applied to modelling costs. These methods can be divided into several main groups: (1 artificial intelligence, (2 statistical methods, and (3 analytical methods. In this paper, the multivariate regression (MVR method, which is one of the most popular linear models, and the artificial neural network (ANN method, which is widely applied to solving different prediction problems with a high degree of accuracy, have been combined to provide a cost estimate model for a shovel machine. This hybrid methodology is proposed, taking the advantages of MVR and ANN models in linear and nonlinear modelling, respectively. In the proposed model, the unique advantages of the MVR model in linear modelling are used first to recognize the existing linear structure in data, and, then, the ANN for determining nonlinear patterns in preprocessed data is applied. The results with three indices indicate that the proposed model is efficient and capable of increasing the prediction accuracy.

Cost-effective handoff scheme based on mobility-aware dual pointer forwarding in proxy mobile IPv6 networks.

Science.gov (United States)

Son, Seungsik; Jeong, Jongpil

2014-01-01

In this paper, a mobility-aware Dual Pointer Forwarding scheme (mDPF) is applied in Proxy Mobile IPv6 (PMIPv6) networks. The movement of a Mobile Node (MN) is classified as intra-domain and inter-domain handoff. When the MN moves, this scheme can reduce the high signaling overhead for intra-handoff/inter-handoff, because the Local Mobility Anchor (LMA) and Mobile Access Gateway (MAG) are connected by pointer chains. In other words, a handoff is aware of low mobility between the previously attached MAG (pMAG) and newly attached MAG (nMAG), and another handoff between the previously attached LMA (pLMA) and newly attached LMA (nLMA) is aware of high mobility. Based on these mobility-aware binding updates, the overhead of the packet delivery can be reduced. Also, we analyse the binding update cost and packet delivery cost for route optimization, based on the mathematical analytic model. Analytical results show that our mDPF outperforms the PMIPv6 and the other pointer forwarding schemes, in terms of reducing the total cost of signaling.

Application of Butterfly Clos-Network in Network-on-Chip

Directory of Open Access Journals (Sweden)

Hui Liu

2014-01-01

Full Text Available This paper studied the topology of NoC (Network-on-Chip. By combining the characteristics of the Clos network and butterfly network, a new topology named BFC (Butterfly Clos-network network was proposed. This topology integrates several modules, which belongs to the same layer but different dimensions, into a new module. In the BFC network, a bidirectional link is used to complete information exchange, instead of information exchange between different layers in the original network. During the routing period, other nondestination nodes can be used as middle stages to transfer data packets to complete the routing mission. Therefore, this topology has the characteristic of multistage. Simulation analyses show that BFC inherits the rich path diversity of Clos network, and it has a better performance than butterfly network in throughput and delay in a quite congested traffic pattern.

Large Scale Environmental Monitoring through Integration of Sensor and Mesh Networks

Directory of Open Access Journals (Sweden)

Raja Jurdak

2008-11-01

Full Text Available Monitoring outdoor environments through networks of wireless sensors has received interest for collecting physical and chemical samples at high spatial and temporal scales. A central challenge to environmental monitoring applications of sensor networks is the short communication range of the sensor nodes, which increases the complexity and cost of monitoring commodities that are located in geographically spread areas. To address this issue, we propose a new communication architecture that integrates sensor networks with medium range wireless mesh networks, and provides users with an advanced web portal for managing sensed information in an integrated manner. Our architecture adopts a holistic approach targeted at improving the user experience by optimizing the system performance for handling data that originates at the sensors, traverses the mesh network, and resides at the server for user consumption. This holistic approach enables users to set high level policies that can adapt the resolution of information collected at the sensors, set the preferred performance targets for their application, and run a wide range of queries and analysis on both real-time and historical data. All system components and processes will be described in this paper.

Large Scale Environmental Monitoring through Integration of Sensor and Mesh Networks.

Science.gov (United States)

Jurdak, Raja; Nafaa, Abdelhamid; Barbirato, Alessio

2008-11-24

Monitoring outdoor environments through networks of wireless sensors has received interest for collecting physical and chemical samples at high spatial and temporal scales. A central challenge to environmental monitoring applications of sensor networks is the short communication range of the sensor nodes, which increases the complexity and cost of monitoring commodities that are located in geographically spread areas. To address this issue, we propose a new communication architecture that integrates sensor networks with medium range wireless mesh networks, and provides users with an advanced web portal for managing sensed information in an integrated manner. Our architecture adopts a holistic approach targeted at improving the user experience by optimizing the system performance for handling data that originates at the sensors, traverses the mesh network, and resides at the server for user consumption. This holistic approach enables users to set high level policies that can adapt the resolution of information collected at the sensors, set the preferred performance targets for their application, and run a wide range of queries and analysis on both real-time and historical data. All system components and processes will be described in this paper.

Migration towards fibre to the home: key cost factors

Science.gov (United States)

Zhou, L. W.; Mas Machuca, C.; Zhao, R.; Grunert, K.

2010-12-01

This paper presents a comprehensive cost model for migration towards FTTH, some case study results from different network area scenarios, as well as the identification of the most important cost factors to be considered by operators aiming at increasing the profitability of their networks.

COST network genderSTE: Networking Gender Equality in Research and Innovation in Europe and beyond

Directory of Open Access Journals (Sweden)

Inés Sánchez de Madariaga

2013-06-01

Full Text Available Gender is one of five priorities of the European Research Area, as stated in the Communication adopted in July 2012 entitled A Reinforced European Research Area Partnership for Excellence and Growth (EC 2012c. Following this Communication, the EC has fully integrated gender dimensions in its proposal for a regulation on the new research framework program Horizon 2020¸ which includes in article 15 a provision for gender mainstreaming (EC 2011b. One final upcoming policy instrument announced by the EC is the Recommendation on Gender, Science and Innovation that will address member states and be adopted in the next months. Against this European policy background , the international COST network genderSTE (Gender, Science, Technology and Environment aims at enhancing a better integration of gender dimensions in science and technology at three main levels: i promoting women’s careers in science and technology through structural change of institutions (as recommended by EC by disseminating existing research and practice; ii promoting a better integration of gender in the content of science, research and technology, by dissemination existing research on the topic, ie the UE-US Gendered Innovations Project; iii identifying gender dimensions relevant to environment-related Horizon2020 Grand Challenges and other urban EC initiatives.  

Application and Network-Cognizant Proxies - Final Report

Energy Technology Data Exchange (ETDEWEB)

Antonio Ortega; Daniel C. Lee

2003-03-24

OAK B264 Application and Network-Cognizant Proxies - Final Report. Current networks show increasing heterogeneity both in terms of their bandwidths/delays and the applications they are required to support. This is a trend that is likely to intensify in the future, as real-time services, such as video, become more widely available and networking access over wireless links becomes more widespread. For this reason they propose that application-specific proxies, intermediate network nodes that broker the interactions between server and client, will become an increasingly important network element. These proxies will allow adaptation to changes in network characteristics without requiring a direct intervention of either server or client. Moreover, it will be possible to locate these proxies strategically at those points where a mismatch occurs between subdomains (for example, a proxy could be placed so as to act as a bridge between a reliable network domain and an unreliable one). This design philosophy favors scalability in the sense that the basic network infrastructure can remain unchanged while new functionality can be added to proxies, as required by the applications. While proxies can perform numerous generic functions, such as caching or security, they concentrate here on media-specific, and in particular video-specific, tasks. The goal of this project was to demonstrate that application- and network-specific knowledge at a proxy can improve overall performance especially under changing network conditions. They summarize below the work performed to address these issues. Particular effort was spent in studying caching techniques and on video classification to enable DiffServ delivery. other work included analysis of traffic characteristics, optimized media scheduling, coding techniques based on multiple description coding, and use of proxies to reduce computation costs. This work covered much of what was originally proposed but with a necessarily reduced scope.

Adventist Education: origin, development and expasion

Directory of Open Access Journals (Sweden)

Patrick Vieira Ferreira

2018-03-01

Full Text Available This article aimed to present a brief historical report of the origin, development and consolidation of the Adventist Education Network. Thus, it will be possible to know about its emergence, philosophy of education and the genesis of this confessional network operating in the Brazilian educational scenario for more than a century. The research method includes bibliographical analysis of the main theoreticians of the Brazilian history of education and rescues facts cited by Adventist historians. The research situated the Adventist Education Network in the Brazilian historical context and identified the Seventh-day Adventists as a religious group and as agents in the field of school education.

Optimal urban networks via mass transportation

CERN Document Server

Buttazzo, Giuseppe; Stepanov, Eugene; Solimini, Sergio

2009-01-01

Recently much attention has been devoted to the optimization of transportation networks in a given geographic area. One assumes the distributions of population and of services/workplaces (i.e. the network's sources and sinks) are known, as well as the costs of movement with/without the network, and the cost of constructing/maintaining it. Both the long-term optimization and the short-term, "who goes where" optimization are considered. These models can also be adapted for the optimization of other types of networks, such as telecommunications, pipeline or drainage networks. In the monograph we study the most general problem settings, namely, when neither the shape nor even the topology of the network to be constructed is known a priori.

Effect of various features on the life cycle cost of the timing/synchronization subsystem of the DCS digital communications network

Science.gov (United States)

Kimsey, D. B.

1978-01-01

The effect on the life cycle cost of the timing subsystem was examined, when these optional features were included in various combinations. The features included mutual control, directed control, double-ended reference links, independence of clock error measurement and correction, phase reference combining, self-organization, smoothing for link and nodal dropouts, unequal reference weightings, and a master in a mutual control network. An overall design of a microprocessor-based timing subsystem was formulated. The microprocessor (8080) implements the digital filter portion of a digital phase locked loop, as well as other control functions such as organization of the network through communication with processors at neighboring nodes.

Mathematical model of highways network optimization

Science.gov (United States)

Sakhapov, R. L.; Nikolaeva, R. V.; Gatiyatullin, M. H.; Makhmutov, M. M.

2017-12-01

The article deals with the issue of highways network design. Studies show that the main requirement from road transport for the road network is to ensure the realization of all the transport links served by it, with the least possible cost. The goal of optimizing the network of highways is to increase the efficiency of transport. It is necessary to take into account a large number of factors that make it difficult to quantify and qualify their impact on the road network. In this paper, we propose building an optimal variant for locating the road network on the basis of a mathematical model. The article defines the criteria for optimality and objective functions that reflect the requirements for the road network. The most fully satisfying condition for optimality is the minimization of road and transport costs. We adopted this indicator as a criterion of optimality in the economic-mathematical model of a network of highways. Studies have shown that each offset point in the optimal binding road network is associated with all other corresponding points in the directions providing the least financial costs necessary to move passengers and cargo from this point to the other corresponding points. The article presents general principles for constructing an optimal network of roads.

Traffic-aware Elastic Optical Networks to leverage Energy Savings

DEFF Research Database (Denmark)

Turus, Ioan; Fagertun, Anna Manolova; Dittmann, Lars

2014-01-01

Because of the static nature of the deployed optical networks, large energy wastage is experienced today in production networks such as Telecom networks . With power-adaptive optical interfaces and suitable grooming procedures, we propose the design of more energy efficient transport networks....... Optical network reconfigurations are performed by GMPLS node controllers according to monitored traffic information. The investigated energy reduction strategies are simulated on two large scale transport networks (DT17 and COST37). The results show that the energy savings obtained by these strategies......-Europea n COST37 network, for both symbol-rate and modulation format adaptations significant savings are obtained . Mixed adaptation (jointly performing symbol-rate and modulation format adaptations) used together with optical grooming allows up to 4 4 % and 4 7 % power savings in DT17 and COST37 networks...

Structure and relationships within global manufacturing virtual networks

Directory of Open Access Journals (Sweden)

José Ramón Vilana

2009-04-01

Full Text Available Global Manufacturing Virtual Networks (GMVNs are dynamically changing organizations formed by Original Equipment Manufacturers (OEMs, Contract Manufacturers (CMs, turn-key and component suppliers, R+D centres and distributors. These networks establish a new type of vertical and horizontal relations between independent companies or even competitors where it is not needed to maintain internal manufacturing resources but to manage and share the network resources. The fluid relations that exist within the GMVNs allow them a very permeable organization easy to connect and disconnect from one to each other as well as to choose a set of partners with specific attributes. The result is a highly flexible system characterized by low barriers to entry and exit, geographic flexibility, low costs, rapid technological diffusion, high diversification through contract manufacturers and exceptional economies of scale. Anyhow, there are three major drawbacks in the GMVNs that should be considered at the beginning of this type of collaborations: 1 the risk of contract manufacturers to develop their own end-products in competition with their customers; 2 the technology transfer between competitors OEMs through other members of the GMVN and 3 the lose of process expertise by the OEMs the more they outsource manufacturing processes to the network.

The South Asian Origins of the Global Network to Eradicate Blindness: WHO, NGOs, and Decentralization.

Science.gov (United States)

Williams, Logan D A

2018-03-01

The global network to eradicate blindness emerged out of the work of Western and South Asian professionals to eradicate smallpox which was endemic in South Asia. The history of the emergence of the global network to eradicate blindness demonstrates a shift from vertical command and control public health programs directed by the WHO, to the decentralized public health services originating in non-profit, non-governmental organizations and coordinated by the WHO. The WHO constitution started with a federal regionalist structure that encouraged collaboration and coordination with NGOs. In South Asia in particular, epidemiologists and general medical practitioners moved from eradicating smallpox through the WHO to creating their own domestic and international NGOs based in various countries with a mission to control blindness in South Asia and Africa. In 1975, pushed by the WHO Director General, these new NGOs in turn joined with individual ophthalmologists and existing blind member associations to form the International Agency for the Prevention of Blindness. Thus, the WHO was shaped by, and shaping, international NGOs such as the IAPB. The IAPB pushed for the formation of the WHO Prevention of Blindness program. This was the earliest example of how the IAPB facilitates bottom-up agenda-setting in the WHO. In 1980, when the WHO officially closed the smallpox program, the Prevention of Blindness program first received independent funding. Presently, the IAPB acts as a decentralized arm of the WHO. Copyright © 2018 Elsevier Ltd. All rights reserved.

Minimum cost dynamic flows: The series-parallel case

NARCIS (Netherlands)

Klinz, Bettina; Woeginger, Gerhard

2004-01-01

A dynamic network consists of a directed graph with capacities, costs, and integral transit times on the arcs. In the minimum-cost dynamic flow problem (MCDFP), the goal is to compute, for a given dynamic network with source s, sink t, and two integers v and T, a feasible dynamic flow from s to t of

A Process Management System for Networked Manufacturing

Science.gov (United States)

Liu, Tingting; Wang, Huifen; Liu, Linyan

With the development of computer, communication and network, networked manufacturing has become one of the main manufacturing paradigms in the 21st century. Under the networked manufacturing environment, there exist a large number of cooperative tasks susceptible to alterations, conflicts caused by resources and problems of cost and quality. This increases the complexity of administration. Process management is a technology used to design, enact, control, and analyze networked manufacturing processes. It supports efficient execution, effective management, conflict resolution, cost containment and quality control. In this paper we propose an integrated process management system for networked manufacturing. Requirements of process management are analyzed and architecture of the system is presented. And a process model considering process cost and quality is developed. Finally a case study is provided to explain how the system runs efficiently.

Eco-efficient based logistics network design in hybrid manufacturing/ remanufacturing system in low-carbon economy

Directory of Open Access Journals (Sweden)

Yacan Wang

2013-03-01

Full Text Available Purpose: Low-carbon economy requires the pursuit of eco-efficiency, which is a win-win situation between economic and environmental efficiency. In this paper the question of trading off the economic and environmental effects embodied in eco-efficiency in the hybrid manufacturing/remanufacturing logistics network design in the context of low-carbon economy is examined.Design/methodology/approach: A multi-objective mixed integer linear programming model to find the optimal facility locations and materials flow allocation is established. In the objective function, three minimum targets are set: economic cost, CO2 emission and waste generation. Through an iterative algorithm, the Pareto Boundary of the problem is obtained.Findings: The results of numeric study show that in order to achieve a Pareto improvement over an original system, three of the critical rates (i.e. return rate, recovery rate, and cost substitute rate should be increased.Practical implications: To meet the need of low-carbon dioxide, an iso- CO2 emission curve in which decision makers have a series of optimal choices with the same CO2 emission but different cost and waste generation is plotted. Each choice may have different network design but all of these are Pareto optimal solutions, which provide a comprehensive evaluation of both economics and ecology for the decision making.Originality/value: This research chooses carbon emission as one of the three objective functions and uses Pareto sets to analyze how to balance profitability and environmental impacts in designing remanufacturing closed-loop supply chain in the context of low-carbon economy.

A cost and economic evaluation of the Leeds personality disorder managed clinical network-A service and commissioning development initiative.

Science.gov (United States)

Kane, Eddie; Reeder, Neil; Keane, Kimberley; Prince, Sharon

2016-08-01

In the UK, patients with personality disorders presenting complex needs frequently experience an unhelpful pattern of acute treatment followed by community care-with associated high cost implications for services. With UK mental health resources under severe pressure, this leaves commissioners with difficult decisions to make. Yet studies on cost-effectiveness in respect of personality disorder treatment are scarce, particularly for treatments taking place outside of major teaching hospitals in the USA. This paper studies the benefits of an intensive, holistic approach and finds that the Network achieved substantial reductions in health care usage and expenditure in the short to medium term. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Low Cost Wireless Sensor Network for Continuous Bridge monitoring

DEFF Research Database (Denmark)

Han, Bo; Kalis, A; Tragas, P

2012-01-01

Continuous monitoring wireless sensor networks (WSN) are considered as one of the most promising means to harvest information from large structures in order to assist in structural health monitoring and management. At the same time, continuous monitoring WSNs suffer from limited network lifetimes...

Robust Networking Architecture and Secure Communication Scheme for Heterogeneous Wireless Sensor Networks

Science.gov (United States)

McNeal, McKenzie, III.

2012-01-01

Current networking architectures and communication protocols used for Wireless Sensor Networks (WSNs) have been designed to be energy efficient, low latency, and long network lifetime. One major issue that must be addressed is the security in data communication. Due to the limited capabilities of low cost and small sized sensor nodes, designing…

Extending the coverage of the internet of things with low-cost nanosatellite networks

Science.gov (United States)

Almonacid, Vicente; Franck, Laurent

2017-09-01

Recent technology advances have made CubeSats not only an affordable means of access to space, but also promising platforms to develop a new variety of space applications. In this paper, we explore the idea of using nanosatellites as access points to provide extended coverage to the Internet of Things (IoT) and Machine-to-Machine (M2M) communications. This study is mainly motivated by two facts: on the one hand, it is already obvious that the number of machine-type devices deployed globally will experiment an exponential growth over the forthcoming years. This trend is pushed by the available terrestrial cellular infrastructure, which allows adding support for M2M connectivity at marginal costs. On the other hand, the same growth is not observed in remote areas that must rely on space-based connectivity. In such environments, the demand for M2M communications is potentially large, yet it is challenged by the lack of cost-effective service providers. The traffic characteristics of typical M2M applications translate into the requirement for an extremely low cost per transmitted message. Under these strong economical constraints, we expect that nanosatellites in the low Earth orbit will play a fundamental role in overcoming what we may call the IoT digital divide. The objective of this paper is therefore to provide a general analysis of a nanosatellite-based, global IoT/M2M network. We put emphasis in the engineering challenges faced in designing the Earth-to-Space communication link, where the adoption of an efficient multiple-access scheme is paramount for ensuring connectivity to a large number of terminal nodes. In particular, the trade-offs energy efficiency-access delay and energy efficiency-throughput are discussed, and a novel access approach suitable for delay-tolerant applications is proposed. Thus, by keeping a system-level standpoint, we identify key issues and discuss perspectives towards energy efficient and cost-effective solutions.

ORIGINAL ARTICLES Financial and economic costs of scaling up ...

African Journals Online (AJOL)

provision of free HAART to HIV-infected health professionals should be .... additional working hours is a fixed labour cost (of R55 799 per year). Estimates of staff .... tend to be unreliable as they are often partially completed, long after the actual ...

Vulnerability of network of networks

Science.gov (United States)

Havlin, S.; Kenett, D. Y.; Bashan, A.; Gao, J.; Stanley, H. E.

2014-10-01

Our dependence on networks - be they infrastructure, economic, social or others - leaves us prone to crises caused by the vulnerabilities of these networks. There is a great need to develop new methods to protect infrastructure networks and prevent cascade of failures (especially in cases of coupled networks). Terrorist attacks on transportation networks have traumatized modern societies. With a single blast, it has become possible to paralyze airline traffic, electric power supply, ground transportation or Internet communication. How, and at which cost can one restructure the network such that it will become more robust against malicious attacks? The gradual increase in attacks on the networks society depends on - Internet, mobile phone, transportation, air travel, banking, etc. - emphasize the need to develop new strategies to protect and defend these crucial networks of communication and infrastructure networks. One example is the threat of liquid explosives a few years ago, which completely shut down air travel for days, and has created extreme changes in regulations. Such threats and dangers warrant the need for new tools and strategies to defend critical infrastructure. In this paper we review recent advances in the theoretical understanding of the vulnerabilities of interdependent networks with and without spatial embedding, attack strategies and their affect on such networks of networks as well as recently developed strategies to optimize and repair failures caused by such attacks.

Components of the costs of controlling quality: a transaction cost economics approach.

Science.gov (United States)

Stiles, R A; Mick, S S

1997-01-01

This article identifies the components that contribute to a healthcare organization's costs in controlling quality. A central tenet of our argument is that at its core, quality is the result of a series of transactions among members of a diverse network. Transaction cost economics is applied internally to analyze intraorganizational transactions that contribute to quality control, and questions for future research are posed.

Teachers’ motives for learning in networks : costs, rewards and community interest

NARCIS (Netherlands)

van den Beemt, A.A.J.; Ketelaar, E.; Diepstraten, I.; de Laat, M.

2018-01-01

Background: This paper discusses teachers’ perspectives on learning networks and their motives for participating in these networks. Although it is widely held that teachers’ learning may be developed through learning networks, not all teachers participate in such networks. Purpose: The theme of

Computing motion using resistive networks

Science.gov (United States)

Koch, Christof; Luo, Jin; Mead, Carver; Hutchinson, James

1988-01-01

Recent developments in the theory of early vision are described which lead from the formulation of the motion problem as an ill-posed one to its solution by minimizing certain 'cost' functions. These cost or energy functions can be mapped onto simple analog and digital resistive networks. It is shown how the optical flow can be computed by injecting currents into resistive networks and recording the resulting stationary voltage distribution at each node. These networks can be implemented in cMOS VLSI circuits and represent plausible candidates for biological vision systems.

Lack of evolvability in self-sustaining autocatalytic networks constraints metabolism-first scenarios for the origin of life.

Science.gov (United States)

Vasas, Vera; Szathmáry, Eörs; Santos, Mauro

2010-01-26

A basic property of life is its capacity to experience Darwinian evolution. The replicator concept is at the core of genetics-first theories of the origin of life, which suggest that self-replicating oligonucleotides or their similar ancestors may have been the first "living" systems and may have led to the evolution of an RNA world. But problems with the nonenzymatic synthesis of biopolymers and the origin of template replication have spurred the alternative metabolism-first scenario, where self-reproducing and evolving proto-metabolic networks are assumed to have predated self-replicating genes. Recent theoretical work shows that "compositional genomes" (i.e., the counts of different molecular species in an assembly) are able to propagate compositional information and can provide a setup on which natural selection acts. Accordingly, if we stick to the notion of replicator as an entity that passes on its structure largely intact in successive replications, those macromolecular aggregates could be dubbed "ensemble replicators" (composomes) and quite different from the more familiar genes and memes. In sharp contrast with template-dependent replication dynamics, we demonstrate here that replication of compositional information is so inaccurate that fitter compositional genomes cannot be maintained by selection and, therefore, the system lacks evolvability (i.e., it cannot substantially depart from the asymptotic steady-state solution already built-in in the dynamical equations). We conclude that this fundamental limitation of ensemble replicators cautions against metabolism-first theories of the origin of life, although ancient metabolic systems could have provided a stable habitat within which polymer replicators later evolved.

Staying Safe on Social Network Sites

Science.gov (United States)

... Tips Security Tip (ST06-003) Staying Safe on Social Networking Sites Original release date: January 26, 2011 | Last revised: ... so you should take certain precautions. What are social networking sites? Social networking sites, sometimes referred to as "friend- ...

Marginal pricing of transmission services. An analysis of cost recovery

Energy Technology Data Exchange (ETDEWEB)

Perez-Arriaga, I.J.., Rubio, F.J. [Instituto de Investigacion Technologica, Universidad Pontificia Comillas, Madrid (Spain); Puerta, J.F.; Arceluz, J.; Marin, J. [Unidad de Planificacion Estrategica, Iberdrola, Madrid (Spain)

1996-12-31

The authors present an in-depth analysis of network revenues that are computed with marginal pricing, and investigate the reasons why marginal prices in actual power systems fail to recover total incurred network costs. The major causes of the failure are identified and illustrated with numerical examples. The paper analyzes the regulatory implications of marginal network pricing in the context of competitive electricity markets and provides suggestions for the meaningful allocation of network costs among users. 5 figs., 9 tabs., 8 refs.

Marginal pricing of transmission services. An analysis of cost recovery

International Nuclear Information System (INIS)

Perez-Arriaga, I.J.., Rubio, F.J.; Puerta, J.F.; Arceluz, J.; Marin, J.

1996-01-01

The authors present an in-depth analysis of network revenues that are computed with marginal pricing, and investigate the reasons why marginal prices in actual power systems fail to recover total incurred network costs. The major causes of the failure are identified and illustrated with numerical examples. The paper analyzes the regulatory implications of marginal network pricing in the context of competitive electricity markets and provides suggestions for the meaningful allocation of network costs among users. 5 figs., 9 tabs., 8 refs

Secure Chaotic Map Based Block Cryptosystem with Application to Camera Sensor Networks

Directory of Open Access Journals (Sweden)

Muhammad Khurram Khan

2011-01-01

Full Text Available Recently, Wang et al. presented an efficient logistic map based block encryption system. The encryption system employs feedback ciphertext to achieve plaintext dependence of sub-keys. Unfortunately, we discovered that their scheme is unable to withstand key stream attack. To improve its security, this paper proposes a novel chaotic map based block cryptosystem. At the same time, a secure architecture for camera sensor network is constructed. The network comprises a set of inexpensive camera sensors to capture the images, a sink node equipped with sufficient computation and storage capabilities and a data processing server. The transmission security between the sink node and the server is gained by utilizing the improved cipher. Both theoretical analysis and simulation results indicate that the improved algorithm can overcome the flaws and maintain all the merits of the original cryptosystem. In addition, computational costs and efficiency of the proposed scheme are encouraging for the practical implementation in the real environment as well as camera sensor network.

Design of Supply Chain Networks with Supply Disruptions using Genetic Algorithm

OpenAIRE

Taha, Raghda; Abdallah, Khaled; Sadek, Yomma; El-Kharbotly, Amin; Afia, Nahid

2014-01-01

The design of supply chain networks subject to disruptions is tackled. A genetic algorithm with the objective of minimizing the design cost and regret cost is developed to achieve a reliable supply chain network. The improvement of supply chain network reliability is measured against the supply chain cost.

Synergistic stiffening in double-fiber networks

NARCIS (Netherlands)

Rombouts, W.H.; Giesbers, M.; Lent, van J.W.M.; Wolf, de F.A.; Gucht, van der J.

2014-01-01

Many biological materials are composite structures, interpenetrating networks of different types of fibers. The composite nature of such networks leads to superior mechanical properties, but the origin of this mechanical synergism is still poorly understood. Here we study soft composite networks,

Friends First? The Peer Network Origins of Adolescent Dating

Science.gov (United States)

Kreager, Derek A.; Molloy, Lauren E.; Moody, James; Feinberg, Mark E.

2015-01-01

The proximity of dating partners in peer friendship networks has important implications for the diffusion of health-risk behaviors and adolescent social development. We derive two competing hypotheses for the friendship-romance association. The first predicts that daters are proximally positioned in friendship networks prior to dating and that opposite-gender friends are likely to transition to dating. The second predicts that dating typically crosses group boundaries and opposite-gender friends are unlikely to later date. We test these hypotheses with longitudinal friendship data for 626 9th grade PROSPER heterosexual dating couples. Results primarily support the second hypothesis: romantic partners are unlikely to be friends in the previous year or share the same cohesive subgroup, and opposite-gender friends are unlikely to transition into dating. PMID:27134511

A Study of Rank Defect and Network Effect in Processing the CMONOC Network on Bernese

Directory of Open Access Journals (Sweden)

Weiwei Wu

2018-02-01

Full Text Available High-precision GPS data processing on Bernese has been employed to routinely resolve daily position solutions of GPS stations in the Crustal Movement Observation Network of China (CMONOC. The rank-deficient problems of the normal equation (NEQ system and the network effect on the frame alignment of NEQs in the processing of CMONOC data on Bernese still present difficulties. In this study, we diagnose the rank-deficient problems of the original NEQ, review the efficiency of the controlled datum removal (CDR method in filtering out the three frame-origin-related datum contents, investigate the reliabilities of the inherited frame orientation and scale information from the fixation of the GPS satellite orbits and the Earth rotation parameters in establishing the NEQ of the CMONOC network on Bernese, and analyze the impact of the network effect on the position time series of GPS stations. Our results confirm the nonsingularity of the original NEQ and the efficiency of the CDR filtering in resolving the rank-deficient problems; show that the frame origin parameters are weakly defined and should be stripped off, while the frame orientation and scale parameters should be retained due to their insufficient redefinition from the minimal constraint (MC implementation through inhomogeneous and asymmetrical fiducial networks; and reveal the superiority of a globally distributed fiducial network for frame alignment of the reconstructed NEQs via No-Net-Translation (NNT MC conditions. Finally, we attribute the two apparent discontinuities in the position time series to the terrestrial reference frame (TRF conversions of the GPS satellite orbits, and identify it as the orbit TRF effect.

Introduction of a super speed network in JNC

International Nuclear Information System (INIS)

Nosaki, Nobuhisa; Aoki, Kazuhisa; Narita, Nobuiku

2002-01-01

The construction of a super speed and broadband network with high cost performance is now possible through the resent remarkable development of information-communication technologies. Under such circumstances, the modification of LAN and WAN to the super speed network was required in accordance with the recent network demand in JNC. The trend of the information-communication technologies and the needs of information-communication infrastructure were reviewed as the first step. A modification of WAN to the super speed network with high cost performance was established in fiscal year 2000. This paper introduces the work procedures and the modification of the WAN in order to acquire a reduction in the running cost and the super speed network in the fiscal year. (author)

A Squeezed Artificial Neural Network for the Symbolic Network Reliability Functions of Binary-State Networks.

Science.gov (United States)

Yeh, Wei-Chang

Network reliability is an important index to the provision of useful information for decision support in the modern world. There is always a need to calculate symbolic network reliability functions (SNRFs) due to dynamic and rapid changes in network parameters. In this brief, the proposed squeezed artificial neural network (SqANN) approach uses the Monte Carlo simulation to estimate the corresponding reliability of a given designed matrix from the Box-Behnken design, and then the Taguchi method is implemented to find the appropriate number of neurons and activation functions of the hidden layer and the output layer in ANN to evaluate SNRFs. According to the experimental results of the benchmark networks, the comparison appears to support the superiority of the proposed SqANN method over the traditional ANN-based approach with at least 16.6% improvement in the median absolute deviation in the cost of extra 2 s on average for all experiments.Network reliability is an important index to the provision of useful information for decision support in the modern world. There is always a need to calculate symbolic network reliability functions (SNRFs) due to dynamic and rapid changes in network parameters. In this brief, the proposed squeezed artificial neural network (SqANN) approach uses the Monte Carlo simulation to estimate the corresponding reliability of a given designed matrix from the Box-Behnken design, and then the Taguchi method is implemented to find the appropriate number of neurons and activation functions of the hidden layer and the output layer in ANN to evaluate SNRFs. According to the experimental results of the benchmark networks, the comparison appears to support the superiority of the proposed SqANN method over the traditional ANN-based approach with at least 16.6% improvement in the median absolute deviation in the cost of extra 2 s on average for all experiments.

A Benefit/Cost/Deficit (BCD) model for learning from human errors

International Nuclear Information System (INIS)

Vanderhaegen, Frederic; Zieba, Stephane; Enjalbert, Simon; Polet, Philippe

2011-01-01

This paper proposes an original model for interpreting human errors, mainly violations, in terms of benefits, costs and potential deficits. This BCD model is then used as an input framework to learn from human errors, and two systems based on this model are developed: a case-based reasoning system and an artificial neural network system. These systems are used to predict a specific human car driving violation: not respecting the priority-to-the-right rule, which is a decision to remove a barrier. Both prediction systems learn from previous violation occurrences, using the BCD model and four criteria: safety, for identifying the deficit or the danger; and opportunity for action, driver comfort, and time spent; for identifying the benefits or the costs. The application of learning systems to predict car driving violations gives a rate over 80% of correct prediction after 10 iterations. These results are validated for the non-respect of priority-to-the-right rule.

Cost-Benefit Analysis of Smart Grids Implementation

International Nuclear Information System (INIS)

Tomsic, Z.; Pongrasic, M.

2014-01-01

Paper presents guidelines for conducting the cost-benefit analysis of Smart Grid projects connected to the implementation of advanced technologies in electric power system. Restrictions of presented electric power networks are also mentioned along with solutions that are offered by advanced electric power network. From an economic point of view, the main characteristic of advanced electric power network is big investment, and benefits are seen after some time with risk of being smaller than expected. Therefore it is important to make a comprehensive analysis of those projects which consist of economic and qualitative analysis. This report relies on EPRI methodology developed in American institute for energy. The methodology is comprehensive and useful, but also simple and easy to understand. Steps of this methodology and main characteristics of methodologies which refer to EPRI methodology: methodology developed in Joint Research Center and methodologies for analysing implementation of smart meters in electricity power network are explained. Costs, benefits and categories in which they can be classified are also defined. As a part of qualitative analysis, social aspect of Smart Grid projects is described. In cost defining, special attention has to be paid to projects of integrating electricity from variable renewable energy sources into the power system because of additional costs. This work summarized categories of additional costs. In the end of this report, an overview is given of what has been done and what will be done in European Union. (author).

Design Guidelines for New Generation Network Architecture

Science.gov (United States)

Harai, Hiroaki; Fujikawa, Kenji; Kafle, Ved P.; Miyazawa, Takaya; Murata, Masayuki; Ohnishi, Masaaki; Ohta, Masataka; Umezawa, Takeshi

Limitations are found in the recent Internet because a lot of functions and protocols are patched to the original suite of layered protocols without considering global optimization. This reveals that end-to-end argument in the original Internet was neither sufficient for the current societal network and nor for a sustainable network of the future. In this position paper, we present design guidelines for a future network, which we call the New Generation Network, which provides the inclusion of diverse human requirements, reliable connection between the real-world and virtual network space, and promotion of social potentiality for human emergence. The guidelines consist of the crystal synthesis, the reality connection, and the sustainable & evolutional guidelines.

Social Interaction in Learning Networks

NARCIS (Netherlands)

Sloep, Peter

2009-01-01

The original publication is available from www.springerlink.com. Sloep, P. (2009). Social Interaction in Learning Networks. In R. Koper (Ed.), Learning Network Services for Professional Development (pp 13-15). Berlin, Germany: Springer Verlag.

Social Networks and Political Parties in Chile

OpenAIRE

Adler Lomnitz, Larissa

2002-01-01

This paper describes the origin and evolution of two Chilean political parties (the Radical Party and the Christian Democrat Party) through the analysis of the social networks that originated and composed them. The aim of this study is to propose a model of national political cultures on the basis of the structure of social networks related to power and of the symbol system, which legitimizes it. The structure of social networks, horizontal and vertical, are based on reciprocal or redistribut...

Rede própria ou rede credenciada: análise comparativa de custos em uma operadora brasileira de planos de saúde Self-owned versus accredited network: comparative cost analysis in a Brazilian health insurance provider

Directory of Open Access Journals (Sweden)

Marcos Antônio de Souza

2010-10-01

Full Text Available OBJETIVO: Analisar os custos da rede própria de uma operadora brasileira de planos de saúde comparativamente com o preço cobrado pela rede credenciada, visando a identificar se a opção estratégica da operadora em ter rede própria representou vantagem econômica. MÉTODOS: Este estudo exploratório foi desenvolvido mediante pesquisa nos relatórios gerenciais da empresa. O custo da rede própria foi calculado com base nas consultas médicas e odontológicas e nos exames diagnósticos e laboratoriais realizados em uma unidade representativa da operadora. Os custos com terceirizados foram obtidos da tabela de preços praticados pela rede credenciada para os mesmos serviços analisados na rede própria. Para a quantificação dos custos foi utilizado o método de custeio pleno. Os custos são apresentados em termos absolutos (em R$ e em percentuais dos custos próprios em relação aos da rede credenciada. RESULTADOS: De modo geral há vantagem para a operadora em utilizar sua própria rede. Isso é verdadeiro para consultas médicas, odontológicas e exames. São exceções as consultas nas especialidades de pediatria e medicina do trabalho e os exames de raio-X. CONCLUSÕES: A opção da operadora pela verticalização do serviço apresenta vantagens econômicas para a empresa em relação à terceirização.OBJECTIVE: To analyze the cost of a self-owned network maintained by a Brazilian health insurance provider as compared to the price charged by accredited service providers, so as to identify whether or not the self-owned network is economically advantageous. METHODS: For this exploratory study, the company's management reports were reviewed. The cost associated with the self-owned network was calculated based on medical and dental office visits and diagnostic/laboratory tests performed at one of the company's most representative facilities. The costs associated with third parties were derived from price tables used by the accredited

Equity in multiproduct supply chain network

Directory of Open Access Journals (Sweden)

Mina SAEE BOSTANABAD

2013-01-01

Full Text Available In this paper, multiproduct supply chain network is investigated with equity consideration,namely, obtaining the optimal flow pattern, in such a way that no user in the network can increasehis(her benefit with change in product’s sending path. However, each kind of products, has anindividual cost function and, at the same time, contributes to its own and other product’s cost functionin an individual way. An algorithm is developed to find optimal flow pattern for such multiproductsupply chain network.

Origin of an extensive network of non-tectonic synclines in Eocene limestones of the Western Desert, Egypt

Science.gov (United States)

Tewksbury, Barbara J.; Tarabees, Elhamy A.; Mehrtens, Charlotte J.

2017-12-01

Satellite images of the Western Desert of Egypt display conspicuous sinuous color patterning that previous workers have interpreted as erosional flutes formed by catastrophic flooding. Our work with high resolution satellite imagery shows that the patterning is not erosional but, rather, the result of a network of thousands of narrow synclines in the Eocene bedrock capping the Limestone Plateau. Synclines form as isolated, 200-400 meter-wide downwarps in otherwise flat-lying strata. Limb dips are shallow, and doubly plunging hinges form multiple basin closures along syncline lengths. Anticlines form ;accidentally; in inter-syncline areas where two adjacent synclines lie close together. Synclines have two dominant orientations, WNW-ESE and NNW-SSE, parallel to two prominent joint and fault sets, and synclines branch, merge, and change orientation along their lengths. Synclines are all at the same scale with neither larger structures nor parasitic structures and are best described as non-tectonic sag synclines. An Egypt-wide inventory reveals that these synclines are both confined to Eocene limestones and developed, albeit it sporadically, over nearly 100,000 km2. The syncline network predates plateau gravels of the Katkut Formation, which have been interpreted as Oligocene or early Miocene in age, and the network is cut by faults related to Western Desert extension associated with Red Sea rifting. The mechanism that caused sag of overlying layers is not clear. Modern karst collapse, subsurface dissolution of evaporites, and collapse of paleokarst are all unlikely mechanisms given the timing of formation and the underlying stratigraphy. Silica diagenesis and downslope mobilization of underlying shales are possibilities, although uncertainty about the origin of silica in the limestones, plus the consistency of syncline orientations over large areas, make these models problematic. Hypogene karst, perhaps related to aggressive fluids associated with basaltic intrusions

On the reliability of Quake-Catcher Network earthquake detections

Science.gov (United States)

Yildirim, Battalgazi; Cochran, Elizabeth S.; Chung, Angela I.; Christensen, Carl M.; Lawrence, Jesse F.

2015-01-01

Over the past two decades, there have been several initiatives to create volunteer‐based seismic networks. The Personal Seismic Network, proposed around 1990, used a short‐period seismograph to record earthquake waveforms using existing phone lines (Cranswick and Banfill, 1990; Cranswicket al., 1993). NetQuakes (Luetgert et al., 2010) deploys triaxial Micro‐Electromechanical Systems (MEMS) sensors in private homes, businesses, and public buildings where there is an Internet connection. Other seismic networks using a dense array of low‐cost MEMS sensors are the Community Seismic Network (Clayton et al., 2012; Kohler et al., 2013) and the Home Seismometer Network (Horiuchi et al., 2009). One main advantage of combining low‐cost MEMS sensors and existing Internet connection in public and private buildings over the traditional networks is the reduction in installation and maintenance costs (Koide et al., 2006). In doing so, it is possible to create a dense seismic network for a fraction of the cost of traditional seismic networks (D’Alessandro and D’Anna, 2013; D’Alessandro, 2014; D’Alessandro et al., 2014).

Reliability Improved Cooperative Communication over Wireless Sensor Networks

Directory of Open Access Journals (Sweden)

Zhuangbin Chen

2017-10-01

Full Text Available With the development of smart devices and connection technologies, Wireless Sensor Networks (WSNs are becoming increasingly intelligent. New or special functions can be obtained by receiving new versions of program codes to upgrade their software systems, forming the so-called smart Internet of Things (IoT. Due to the lossy property of wireless channels, data collection in WSNs still suffers from a long delay, high energy consumption, and many retransmissions. Thanks to wireless software-defined networks (WSDNs, software in sensors can now be updated to help them transmit data cooperatively, thereby achieving more reliable communication. In this paper, a Reliability Improved Cooperative Communication (RICC data collection scheme is proposed to improve the reliability of random-network-coding-based cooperative communications in multi-hop relay WSNs without reducing the network lifetime. In WSNs, sensors in different positions can have different numbers of packets to handle, resulting in the unbalanced energy consumption of the network. In particular, nodes in non-hotspot areas have up to 90% of their original energy remaining when the network dies. To efficiently use the residual energy, in RICC, high data transmission power is adopted in non-hotspot areas to achieve a higher reliability at the cost of large energy consumption, and relatively low transmission power is adopted in hotspot areas to maintain the long network lifetime. Therefore, high reliability and a long network lifetime can be obtained simultaneously. The simulation results show that compared with other scheme, RICC can reduce the end-to-end Message Fail delivering Ratio (MFR by 59.4%–62.8% under the same lifetime with a more balanced energy utilization.

The effects of rising energy costs and transportation mode mix on forest fuel procurement costs

International Nuclear Information System (INIS)

Rauch, Peter; Gronalt, Manfred

2011-01-01

Since fossil fuels have been broadly recognized as a non-renewable energy source that threatens the climate, sustainable and CO 2 neutral energy sources - such as forest fuels - are being promoted in Europe, instead. With the expeditiously growing forest fuel demand, the strategic problem of how to design a cost-efficient distribution network has evolved. This paper presents an MILP model, comprising decisions on modes of transportation and spatial arrangement of terminals, in order to design a forest fuel supply network for Austria. The MILP model is used to evaluate the impacts of rising energy costs on procurement sources, transport mix and procurement costs on a national scale, based on the example of Austria. A 20% increase of energy costs results in a procurement cost increase of 7%, and another 20% increase of energy costs would have similar results. While domestic waterways become more important as a result of the first energy cost increase, rail only does so after the second. One way to decrease procurement costs would be to reduce the share of empty trips with truck and trailer. Reducing this share by 10% decreases the average procurement costs by up to 20%. Routing influences the modal split considerably, and the truck transport share increases from 86% to 97%, accordingly. Increasing forest fuel imports by large CHPs lowers domestic competition and also enables smaller plants to cut their procurement costs. Rising forest fuel imports via ship will not significantly decrease domestic market shares, but they will reduce procurement costs considerably. (author)

Neural Network Blind Equalization Algorithm Applied in Medical CT Image Restoration

Directory of Open Access Journals (Sweden)

Yunshan Sun

2013-01-01

Full Text Available A new algorithm for iterative blind image restoration is presented in this paper. The method extends blind equalization found in the signal case to the image. A neural network blind equalization algorithm is derived and used in conjunction with Zigzag coding to restore the original image. As a result, the effect of PSF can be removed by using the proposed algorithm, which contributes to eliminate intersymbol interference (ISI. In order to obtain the estimation of the original image, what is proposed in this method is to optimize constant modulus blind equalization cost function applied to grayscale CT image by using conjugate gradient method. Analysis of convergence performance of the algorithm verifies the feasibility of this method theoretically; meanwhile, simulation results and performance evaluations of recent image quality metrics are provided to assess the effectiveness of the proposed method.

Vulnerability analysis methods for road networks

Science.gov (United States)

Bíl, Michal; Vodák, Rostislav; Kubeček, Jan; Rebok, Tomáš; Svoboda, Tomáš

2014-05-01

Road networks rank among the most important lifelines of modern society. They can be damaged by either random or intentional events. Roads are also often affected by natural hazards, the impacts of which are both direct and indirect. Whereas direct impacts (e.g. roads damaged by a landslide or due to flooding) are localized in close proximity to the natural hazard occurrence, the indirect impacts can entail widespread service disabilities and considerable travel delays. The change in flows in the network may affect the population living far from the places originally impacted by the natural disaster. These effects are primarily possible due to the intrinsic nature of this system. The consequences and extent of the indirect costs also depend on the set of road links which were damaged, because the road links differ in terms of their importance. The more robust (interconnected) the road network is, the less time is usually needed to secure the serviceability of an area hit by a disaster. These kinds of networks also demonstrate a higher degree of resilience. Evaluating road network structures is therefore essential in any type of vulnerability and resilience analysis. There are a range of approaches used for evaluation of the vulnerability of a network and for identification of the weakest road links. Only few of them are, however, capable of simulating the impacts of the simultaneous closure of numerous links, which often occurs during a disaster. The primary problem is that in the case of a disaster, which usually has a large regional extent, the road network may remain disconnected. The majority of the commonly used indices use direct computation of the shortest paths or time between OD (origin - destination) pairs and therefore cannot be applied when the network breaks up into two or more components. Since extensive break-ups often occur in cases of major disasters, it is important to study the network vulnerability in these cases as well, so that appropriate

Telecommunications network modelling, planning and design

CERN Document Server

Evans, Sharon

2003-01-01

Telecommunication Network Modelling, Planning and Design addresses sophisticated modelling techniques from the perspective of the communications industry and covers some of the major issues facing telecommunications network engineers and managers today. Topics covered include network planning for transmission systems, modelling of SDH transport network structures and telecommunications network design and performance modelling, as well as network costs and ROI modelling and QoS in 3G networks.

Nuclear plant life cycle costs

International Nuclear Information System (INIS)

Durante, R.W.

1994-01-01

Life cycle costs of nuclear power plants in the United States are discussed. The author argues that these costs have been mishandled or neglected. Decommissioning costs have escalated, e.g. from $328 per unit in 1991 to $370 in 1993 for the Sacramento Municipal Utility District, though they still only amount to less than 0.1 cent per kWh. Waste management has been complicated in the U.S. by the decision to abandon civilian reprocessing; by the year 2000, roughly 30 U.S. nuclear power units will have filled their storage pools; dry storage has been delayed, and will be an expense not originally envisaged. Some examples of costs of major component replacement are provided. No single component has caused as much operational disruption and financial penalties as the steam generator. Operation and maintenance costs have increased steadily, and now amount to more than 70% of production costs. A strategic plan by the Nuclear Power Oversight Committee (of U.S. utilities) will ensure that the ability to correctly operate and maintain a nuclear power plant is built into the original design. 6 figs

Localization in Wireless Sensor Networks: A Survey on Algorithms, Measurement Techniques, Applications and Challenges

Directory of Open Access Journals (Sweden)

Anup Kumar Paul

2017-10-01

Full Text Available Localization is an important aspect in the field of wireless sensor networks (WSNs that has developed significant research interest among academia and research community. Wireless sensor network is formed by a large number of tiny, low energy, limited processing capability and low-cost sensors that communicate with each other in ad-hoc fashion. The task of determining physical coordinates of sensor nodes in WSNs is known as localization or positioning and is a key factor in today’s communication systems to estimate the place of origin of events. As the requirement of the positioning accuracy for different applications varies, different localization methods are used in different applications and there are several challenges in some special scenarios such as forest fire detection. In this paper, we survey different measurement techniques and strategies for range based and range free localization with an emphasis on the latter. Further, we discuss different localization-based applications, where the estimation of the location information is crucial. Finally, a comprehensive discussion of the challenges such as accuracy, cost, complexity, and scalability are given.

Influence of degree correlations on network structure and stability in protein-protein interaction networks

Directory of Open Access Journals (Sweden)

Zimmer Ralf

2007-08-01

Full Text Available Abstract Background The existence of negative correlations between degrees of interacting proteins is being discussed since such negative degree correlations were found for the large-scale yeast protein-protein interaction (PPI network of Ito et al. More recent studies observed no such negative correlations for high-confidence interaction sets. In this article, we analyzed a range of experimentally derived interaction networks to understand the role and prevalence of degree correlations in PPI networks. We investigated how degree correlations influence the structure of networks and their tolerance against perturbations such as the targeted deletion of hubs. Results For each PPI network, we simulated uncorrelated, positively and negatively correlated reference networks. Here, a simple model was developed which can create different types of degree correlations in a network without changing the degree distribution. Differences in static properties associated with degree correlations were compared by analyzing the network characteristics of the original PPI and reference networks. Dynamics were compared by simulating the effect of a selective deletion of hubs in all networks. Conclusion Considerable differences between the network types were found for the number of components in the original networks. Negatively correlated networks are fragmented into significantly less components than observed for positively correlated networks. On the other hand, the selective deletion of hubs showed an increased structural tolerance to these deletions for the positively correlated networks. This results in a lower rate of interaction loss in these networks compared to the negatively correlated networks and a decreased disintegration rate. Interestingly, real PPI networks are most similar to the randomly correlated references with respect to all properties analyzed. Thus, although structural properties of networks can be modified considerably by degree

Resilience-based optimal design of water distribution network

Science.gov (United States)

Suribabu, C. R.

2017-11-01

Optimal design of water distribution network is generally aimed to minimize the capital cost of the investments on tanks, pipes, pumps, and other appurtenances. Minimizing the cost of pipes is usually considered as a prime objective as its proportion in capital cost of the water distribution system project is very high. However, minimizing the capital cost of the pipeline alone may result in economical network configuration, but it may not be a promising solution in terms of resilience point of view. Resilience of the water distribution network has been considered as one of the popular surrogate measures to address ability of network to withstand failure scenarios. To improve the resiliency of the network, the pipe network optimization can be performed with two objectives, namely minimizing the capital cost as first objective and maximizing resilience measure of the configuration as secondary objective. In the present work, these two objectives are combined as single objective and optimization problem is solved by differential evolution technique. The paper illustrates the procedure for normalizing the objective functions having distinct metrics. Two of the existing resilience indices and power efficiency are considered for optimal design of water distribution network. The proposed normalized objective function is found to be efficient under weighted method of handling multi-objective water distribution design problem. The numerical results of the design indicate the importance of sizing pipe telescopically along shortest path of flow to have enhanced resiliency indices.

Airline network structure in competitive market

Directory of Open Access Journals (Sweden)

Babić Danica D.

2014-01-01

Full Text Available Airline's network is the key element of its business strategy and selected network structure will not have influence only on the airline's costs but could gain some advantage in revenues, too. Network designing implies that an airline has to make decisions about markets that it will serve and how to serve those markets. Network choice raises the following questions for an airline: a what markets to serve, b how to serve selected markets, c what level of service to offer, d what are the benefits/cost of the that decisions and e what is the influence of the competition. We analyzed the existing airline business models and corresponding network structure. The paper highlights the relationship between the network structures and the airline business strategies. Using a simple model we examine the relationship between the network structure and service quality in deregulated market.

A paradox for traffic dynamics in complex networks with ATIS

International Nuclear Information System (INIS)

Zheng Jianfeng; Gao Ziyou

2008-01-01

In this work, we study the statistical properties of traffic (e.g., vehicles) dynamics in complex networks, by introducing advanced transportation information systems (ATIS). The ATIS can provide the information of traffic flow pattern throughout the network and have an obvious effect on path routing strategy for such vehicles equipped with ATIS. The ATIS can be described by the understanding of link cost functions. Different indices such as efficiency and system total cost are discussed in depth. It is found that, for random networks (scale-free networks), the efficiency is effectively improved (decreased) if ATIS is properly equipped; however the system total cost is largely increased (decreased). It indicates that there exists a paradox between the efficiency and system total cost in complex networks. Furthermore, we report the simulation results by considering different kinds of link cost functions, and the paradox is recovered. Finally, we extend our traffic model, and also find the existence of the paradox

The APS control system network upgrade

International Nuclear Information System (INIS)

Sidorowicz, K. v.; Leibfritz, D.; McDowell, W. P.

1999-01-01

When it was installed,the Advanced Photon Source (APS) control system network was at the state-of-the-art. Different aspects of the system have been reported at previous meetings [1,2]. As loads on the controls network have increased due to newer and faster workstations and front-end computers, we have found performance of the system declining and have implemented an upgraded network. There have been dramatic advances in networking hardware in the last several years. The upgraded APS controls network replaces the original FDDI backbone and shared Ethernet hubs with redundant gigabit uplinks and fully switched 10/100 Ethernet switches with backplane fabrics in excess of 20 Gbits/s (Gbps). The central collapsed backbone FDDI concentrator has been replaced with a Gigabit Ethernet switch with greater than 30 Gbps backplane fabric. Full redundancy of the system has been maintained. This paper will discuss this upgrade and include performance data and performance comparisons with the original network

Network Restoration for Next-Generation Communication and Computing Networks

Directory of Open Access Journals (Sweden)

B. S. Awoyemi

2018-01-01

Full Text Available Network failures are undesirable but inevitable occurrences for most modern communication and computing networks. A good network design must be robust enough to handle sudden failures, maintain traffic flow, and restore failed parts of the network within a permissible time frame, at the lowest cost achievable and with as little extra complexity in the network as possible. Emerging next-generation (xG communication and computing networks such as fifth-generation networks, software-defined networks, and internet-of-things networks have promises of fast speeds, impressive data rates, and remarkable reliability. To achieve these promises, these complex and dynamic xG networks must be built with low failure possibilities, high network restoration capacity, and quick failure recovery capabilities. Hence, improved network restoration models have to be developed and incorporated in their design. In this paper, a comprehensive study on network restoration mechanisms that are being developed for addressing network failures in current and emerging xG networks is carried out. Open-ended problems are identified, while invaluable ideas for better adaptation of network restoration to evolving xG communication and computing paradigms are discussed.

Optimal river monitoring network using optimal partition analysis: a case study of Hun River, Northeast China.

Science.gov (United States)

Wang, Hui; Liu, Chunyue; Rong, Luge; Wang, Xiaoxu; Sun, Lina; Luo, Qing; Wu, Hao

2018-01-09

River monitoring networks play an important role in water environmental management and assessment, and it is critical to develop an appropriate method to optimize the monitoring network. In this study, an effective method was proposed based on the attainment rate of National Grade III water quality, optimal partition analysis and Euclidean distance, and Hun River was taken as a method validation case. There were 7 sampling sites in the monitoring network of the Hun River, and 17 monitoring items were analyzed once a month during January 2009 to December 2010. The results showed that the main monitoring items in the surface water of Hun River were ammonia nitrogen (NH 4 + -N), chemical oxygen demand, and biochemical oxygen demand. After optimization, the required number of monitoring sites was reduced from seven to three, and 57% of the cost was saved. In addition, there were no significant differences between non-optimized and optimized monitoring networks, and the optimized monitoring networks could correctly represent the original monitoring network. The duplicate setting degree of monitoring sites decreased after optimization, and the rationality of the monitoring network was improved. Therefore, the optimal method was identified as feasible, efficient, and economic.

Economic consequences of extra by-passes in district heating networks. Investment-, running- and maintenance costs; Rundgaangars ekonomiska betydelse foer fjaerrvaermenaeten. Investerings-, drift- och underhaallskostnader

Energy Technology Data Exchange (ETDEWEB)

Herbert, P. [AaF-Energikonsult Stockholm AB, (Sweden)

1995-02-01

For various reasons, extra by-passes are installed in district heating networks to ensure a high flow temperature when the water circulation is insufficient. By `extra by-pass` we here mean a connection between the distribution pipe and the return pipe. This study mainly deals with extra by-passes to prevent freezing. The estimation of the extra by-pass costs is based on the district heating rates. Our assumption is that an extra by-pass can be regarded as a substation in the district heating network, with regard to the demand for the water flow, heat and power. The reason is the difficulty to obtain available facts to estimate the real costs concerning extra by-passes. Therefore, the method can not claim that the information about the costs is exact but gives an indication of the size of them. The valves in an extra by-pass can be set more or less open. We assume that manual valves in extra by-passes are wide open. Thermostatic valves are, however, assumed to be adjusted in order to cause a very small water flow. 2 refs, 16 figs, 9 tabs, 6 appendices

Stochastic network interdiction optimization via capacitated network reliability modeling and probabilistic solution discovery

International Nuclear Information System (INIS)

Ramirez-Marquez, Jose Emmanuel; Rocco S, Claudio M.

2009-01-01

This paper introduces an evolutionary optimization approach that can be readily applied to solve stochastic network interdiction problems (SNIP). The network interdiction problem solved considers the minimization of the cost associated with an interdiction strategy such that the maximum flow that can be transmitted between a source node and a sink node for a fixed network design is greater than or equal to a given reliability requirement. Furthermore, the model assumes that the nominal capacity of each network link and the cost associated with their interdiction can change from link to link and that such interdiction has a probability of being successful. This version of the SNIP is for the first time modeled as a capacitated network reliability problem allowing for the implementation of computation and solution techniques previously unavailable. The solution process is based on an evolutionary algorithm that implements: (1) Monte-Carlo simulation, to generate potential network interdiction strategies, (2) capacitated network reliability techniques to analyze strategies' source-sink flow reliability and, (3) an evolutionary optimization technique to define, in probabilistic terms, how likely a link is to appear in the final interdiction strategy. Examples for different sizes of networks are used throughout the paper to illustrate the approach

Network science

CERN Document Server

Barabasi, Albert-Laszlo

2016-01-01

Networks are everywhere, from the Internet, to social networks, and the genetic networks that determine our biological existence. Illustrated throughout in full colour, this pioneering textbook, spanning a wide range of topics from physics to computer science, engineering, economics and the social sciences, introduces network science to an interdisciplinary audience. From the origins of the six degrees of separation to explaining why networks are robust to random failures, the author explores how viruses like Ebola and H1N1 spread, and why it is that our friends have more friends than we do. Using numerous real-world examples, this innovatively designed text includes clear delineation between undergraduate and graduate level material. The mathematical formulas and derivations are included within Advanced Topics sections, enabling use at a range of levels. Extensive online resources, including films and software for network analysis, make this a multifaceted companion for anyone with an interest in network sci...

Spatial networks

Science.gov (United States)

Barthélemy, Marc

2011-02-01

Complex systems are very often organized under the form of networks where nodes and edges are embedded in space. Transportation and mobility networks, Internet, mobile phone networks, power grids, social and contact networks, and neural networks, are all examples where space is relevant and where topology alone does not contain all the information. Characterizing and understanding the structure and the evolution of spatial networks is thus crucial for many different fields, ranging from urbanism to epidemiology. An important consequence of space on networks is that there is a cost associated with the length of edges which in turn has dramatic effects on the topological structure of these networks. We will thoroughly explain the current state of our understanding of how the spatial constraints affect the structure and properties of these networks. We will review the most recent empirical observations and the most important models of spatial networks. We will also discuss various processes which take place on these spatial networks, such as phase transitions, random walks, synchronization, navigation, resilience, and disease spread.

Quality of Security Service Costing Demonstration for the MSHN Project

National Research Council Canada - National Science Library

Spyropoulou, Evdoxia

2000-01-01

.... Each service has two costs: an initialization cost and a run-time cost. The demonstration illustrates the costs incurred as network modes and security levels are changed. High level and detailed specifications are provided.

Optimization of a truck-drone in tandem delivery network using k-means and genetic algorithm

Directory of Open Access Journals (Sweden)

Sergio Mourelo Ferrandez

2016-04-01

Full Text Available Purpose: The purpose of this paper is to investigate the effectiveness of implementing unmanned aerial delivery vehicles in delivery networks. We investigate the notion of the reduced overall delivery time, energy, and costs for a truck-drone network by comparing the in-tandem system with a stand-alone delivery effort. The objectives are (1 to investigate the time, energy, and costs associated to a truck-drone delivery network compared to standalone truck or drone, (2 to propose an optimization algorithm that determines the optimal number of launch sites and locations given delivery requirements, and drones per truck, (3 to develop mathematical formulations for closed form estimations for the optimal number of launch locations, optimal total time, as well as the associated cost for the system. Design/methodology/approach: The design of the algorithm herein computes the minimal time of delivery utilizing K-means clustering to find launch locations, as well as a genetic algorithm to solve the truck route as a traveling salesmen problem (TSP. The optimal solution is determined by finding the minimum cost associated to the parabolic convex cost function. The optimal min-cost is determined by finding the most efficient launch locations using K-means algorithms to determine launch locations and a genetic algorithm to determine truck route between those launch locations.  Findings: Results show improvements with in-tandem delivery efforts as opposed to standalone systems. Further, multiple drones per truck are more optimal and contribute to savings in both energy and time. For this, we sampled various initialization variables to derive closed form mathematical solutions for the problem. Originality/value: Ultimately, this provides the necessary analysis of an integrated truck-drone delivery system which could be implemented by a company in order to maximize deliveries while minimizing time and energy. Closed-form mathematical solutions can be used as

The transmission tariff - the economic tool for the network infrastructure development

International Nuclear Information System (INIS)

Popescu, Vifor Bogdan; Cirlan, Florica; Mihailescu, Florentina

2004-01-01

The free access to the transmission network is one of the key elements of the electricity market development both at the national and regional levels. The operation of the electricity market needs the appropriate development of its basic infrastructure, the transmission network. In the frame work of the electricity market, the network ensures the electricity transmission under reliable conditions, from the generators to the suppliers and eligible consumers and creates market opportunities for its users. One of the main market tools, which may influence the optimal development of the network structure, by an efficient location signal of the large consumers and generators, is the pricing system. The overall costs of the Transmission System Operator (TSO) for providing the transmission service may be distinctly focused by categories as follows: - Costs of the existing transmission network (fixed costs), maintenance and operation costs, capital costs; - Costs of electricity losses (variable costs); - Development costs needed to eliminate the network congestion (variable costs). The recovery of all costs involved by the transmission service is based on regulated tariff system approved by ANRE. By the tariff system, the transmission and system operator aims both to cover the transmission service cost and provide locational signals for all market players which should lead to the efficient grid operation as well as to the optimal development of its structure. The tariff values reflect the polarization existing in the Romanian Power System (PS), namely: surplus power in the South area of the PS (4G zone) and a power deficit in the North areas of the PS (2G and 5G zones). Electricity demand is more evenly distributed in the territory than the electricity generated. This assertion is based on the following statement: - the tariffs value range of electricity delivered in the transmission network is wider, between 1.13 and 2.39 USD/MWh (51%) than the one related to the zones of

A Low Cost Bluetooth Low Energy Transceiver for Wireless Sensor Network Applications with a Front-end Receiver-Matching Network-Reusing Power Amplifier Load Inductor.

Science.gov (United States)

Liang, Zhen; Li, Bin; Huang, Mo; Zheng, Yanqi; Ye, Hui; Xu, Ken; Deng, Fangming

2017-04-19

In this work, a low cost Bluetooth Low Energy (BLE) transceiver for wireless sensor network (WSN) applications, with a receiver (RX)-matching network-reusing power amplifier (PA) load inductor, is presented. In order to decrease the die area, only two inductors were used in this work. Besides the one used in the voltage control oscillator (VCO), the PA load inductor was reused as the RX impedance matching component in the front-end. Proper controls have been applied to achieve high transmitter (TX) input impedance when the transceiver is in the receiving mode, and vice versa. This allows the TRX-switch/matching network integration without significant performance degradation. The RX adopted a low-IF structure and integrated a single-ended low noise amplifier (LNA), a current bleeding mixer, a 4th complex filter and a delta-sigma continuous time (CT) analog-to-digital converter (ADC). The TX employed a two-point PLL-based architecture with a non-linear PA. The RX achieved a sensitivity of -93 dBm and consumes 9.7 mW, while the TX achieved a 2.97% error vector magnitude (EVM) with 9.4 mW at 0 dBm output power. This design was fabricated in a 0.11 μm complementary metal oxide semiconductor (CMOS) technology and the front-end circuit only occupies 0.24 mm². The measurement results verify the effectiveness and applicability of the proposed BLE transceiver for WSN applications.

Application of customer-interruption costs for optimum distribution planning

International Nuclear Information System (INIS)

Mok, Y.L.; Chung, T.S.

1996-01-01

We present a new methodology for obtaining optimum values of the integrated cost of utility investment with customer interruption in distribution planning for electric power systems by determining the reliability cost and worth of the distribution system. Reliability cost refers to investment cost of the utility in achieving a defined level of reliability. Reliability worth is the benefit gained by the utility customer from an increase of reliability. A computer program has been developed to determine comparative reliability indices for a typical distribution network. With the average interruption cost, outage duration, average disconnected load, cost data for distribution equipment, etc. being known, the relation between reliability cost, reliability worth and reliability at the specified load point are obtained. The optimum reliability of the distribution system is then determined from the minimum cost to the utility with customer interruption. The applicability of this approach is demonstrated by several practical networks. (Author)

COMPLEX NETWORK SIMULATION OF FOREST NETWORK SPATIAL PATTERN IN PEARL RIVER DELTA

Directory of Open Access Journals (Sweden)

Y. Zeng

2017-09-01

Full Text Available Forest network-construction uses for the method and model with the scale-free features of complex network theory based on random graph theory and dynamic network nodes which show a power-law distribution phenomenon. The model is suitable for ecological disturbance by larger ecological landscape Pearl River Delta consistent recovery. Remote sensing and GIS spatial data are available through the latest forest patches. A standard scale-free network node distribution model calculates the area of forest network’s power-law distribution parameter value size; The recent existing forest polygons which are defined as nodes can compute the network nodes decaying index value of the network’s degree distribution. The parameters of forest network are picked up then make a spatial transition to GIS real world models. Hence the connection is automatically generated by minimizing the ecological corridor by the least cost rule between the near nodes. Based on scale-free network node distribution requirements, select the number compared with less, a huge point of aggregation as a future forest planning network’s main node, and put them with the existing node sequence comparison. By this theory, the forest ecological projects in the past avoid being fragmented, scattered disorderly phenomena. The previous regular forest networks can be reduced the required forest planting costs by this method. For ecological restoration of tropical and subtropical in south China areas, it will provide an effective method for the forest entering city project guidance and demonstration with other ecological networks (water, climate network, etc. for networking a standard and base datum.

Sustainable wireless networks

CERN Document Server

Zheng, Zhongming; Xuemin

2013-01-01

This brief focuses on network planning and resource allocation by jointly considering cost and energy sustainability in wireless networks with sustainable energy. The characteristics of green energy and investigating existing energy-efficient green approaches for wireless networks with sustainable energy is covered in the first part of this brief. The book then addresses the random availability and capacity of the energy supply. The authors explore how to maximize the energy sustainability of the network and minimize the failure probability that the mesh access points (APs) could deplete their

The IAEA/WHO network of Secondary Standard Dosimetry Laboratories. SSDL network charter

International Nuclear Information System (INIS)

1999-04-01

In 1976, the International Atomic Energy Agency (IAEA) together with the World Health Organization (WHO) established a Network of Secondary Standard Dosimetry Laboratories (SSDLs), known as the IAEA/WHO SSDL Network. This Network, through SSDLs designated by Member States, provides a direct linkage of national dosimetry standards to the international measurement system of standards traceable to the Bureau International des Poids et Mesures (BIPM), and the dissemination of S.I. quantities and units through the proper calibration of field instruments by the SSDLs. The Network has proved to be of value in improving national capabilities for instrument calibration and the awareness of better accuracy and traceability. Fifty-eight countries have nominated SSDLs for membership in the Network. Unfortunately, some of these SSDLs do not yet function as full members, perhaps because of some uncertainty as to their obligations concerning the Network. Consequently, the Scientific Committee which advises the Network Secretariat has recommended that a Charter be drawn up explaining the privileges, rights and duties of members in the Network which would strengthen their links to the international measurement system. In addition to the duties of members in the Network and the benefits that full members can receive, the Charter also describes how the Network functions and the scope of the work of the SSDLs. In producing this Charter, the advisory group has drawn heavily on the IAEA publication 'Secondary Standard Dosimetry Laboratories: Development and Trends' (1985) which summarizes the origin, development, status and prospects of the IAEA/WHO SSDL Network. The various appendices are effectively up-dates of different parts of this earlier publication, and the original drafting and reviewing bodies are given due recognition. The revisions take into account the experience the Agency has gained in coordinating the activities of the Network for more than 20 years

The IAEA/WHO network of Secondary Standard Dosimetry Laboratories. SSDL network charter

Energy Technology Data Exchange (ETDEWEB)

NONE

1999-04-01

In 1976, the International Atomic Energy Agency (IAEA) together with the World Health Organization (WHO) established a Network of Secondary Standard Dosimetry Laboratories (SSDLs), known as the IAEA/WHO SSDL Network. This Network, through SSDLs designated by Member States, provides a direct linkage of national dosimetry standards to the international measurement system of standards traceable to the Bureau International des Poids et Mesures (BIPM), and the dissemination of S.I. quantities and units through the proper calibration of field instruments by the SSDLs. The Network has proved to be of value in improving national capabilities for instrument calibration and the awareness of better accuracy and traceability. Fifty-eight countries have nominated SSDLs for membership in the Network. Unfortunately, some of these SSDLs do not yet function as full members, perhaps because of some uncertainty as to their obligations concerning the Network. Consequently, the Scientific Committee which advises the Network Secretariat has recommended that a Charter be drawn up explaining the privileges, rights and duties of members in the Network which would strengthen their links to the international measurement system. In addition to the duties of members in the Network and the benefits that full members can receive, the Charter also describes how the Network functions and the scope of the work of the SSDLs. In producing this Charter, the advisory group has drawn heavily on the IAEA publication 'Secondary Standard Dosimetry Laboratories: Development and Trends' (1985) which summarizes the origin, development, status and prospects of the IAEA/WHO SSDL Network. The various appendices are effectively up-dates of different parts of this earlier publication, and the original drafting and reviewing bodies are given due recognition. The revisions take into account the experience the Agency has gained in coordinating the activities of the Network for more than 20 years.

SCM: A method to improve network service layout efficiency with network evolution

Science.gov (United States)

Zhao, Qi; Zhang, Chuanhao

2017-01-01

Network services are an important component of the Internet, which are used to expand network functions for third-party developers. Network function virtualization (NFV) can improve the speed and flexibility of network service deployment. However, with the evolution of the network, network service layout may become inefficient. Regarding this problem, this paper proposes a service chain migration (SCM) method with the framework of “software defined network + network function virtualization” (SDN+NFV), which migrates service chains to adapt to network evolution and improves the efficiency of the network service layout. SCM is modeled as an integer linear programming problem and resolved via particle swarm optimization. An SCM prototype system is designed based on an SDN controller. Experiments demonstrate that SCM could reduce the network traffic cost and energy consumption efficiently. PMID:29267299

SCM: A method to improve network service layout efficiency with network evolution.

Science.gov (United States)

Zhao, Qi; Zhang, Chuanhao; Zhao, Zheng

2017-01-01

Network services are an important component of the Internet, which are used to expand network functions for third-party developers. Network function virtualization (NFV) can improve the speed and flexibility of network service deployment. However, with the evolution of the network, network service layout may become inefficient. Regarding this problem, this paper proposes a service chain migration (SCM) method with the framework of "software defined network + network function virtualization" (SDN+NFV), which migrates service chains to adapt to network evolution and improves the efficiency of the network service layout. SCM is modeled as an integer linear programming problem and resolved via particle swarm optimization. An SCM prototype system is designed based on an SDN controller. Experiments demonstrate that SCM could reduce the network traffic cost and energy consumption efficiently.

Empirical study of long-range connections in a road network offers new ingredient for navigation optimization models

Science.gov (United States)

Wang, Pu; Liu, Like; Li, Xiamiao; Li, Guanliang; González, Marta C.

2014-01-01

Navigation problem in lattices with long-range connections has been widely studied to understand the design principles for optimal transport networks; however, the travel cost of long-range connections was not considered in previous models. We define long-range connection in a road network as the shortest path between a pair of nodes through highways and empirically analyze the travel cost properties of long-range connections. Based on the maximum speed allowed in each road segment, we observe that the time needed to travel through a long-range connection has a characteristic time Th ˜ 29 min, while the time required when using the alternative arterial road path has two different characteristic times Ta ˜ 13 and 41 min and follows a power law for times larger than 50 min. Using daily commuting origin-destination matrix data, we additionally find that the use of long-range connections helps people to save about half of the travel time in their daily commute. Based on the empirical results, we assign a more realistic travel cost to long-range connections in two-dimensional square lattices, observing dramatically different minimum average shortest path but similar optimal navigation conditions.

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

NARCIS (Netherlands)

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

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

A Network Reconfiguration Method Considering Data Uncertainties in Smart Distribution Networks

Directory of Open Access Journals (Sweden)

Ke-yan Liu