Distributed Coordinated Control of Large-Scale Nonlinear Networks

DOE PAGES

Kundu, Soumya; Anghel, Marian

2015-11-08

We provide a distributed coordinated approach to the stability analysis and control design of largescale nonlinear dynamical systems by using a vector Lyapunov functions approach. In this formulation the large-scale system is decomposed into a network of interacting subsystems and the stability of the system is analyzed through a comparison system. However finding such comparison system is not trivial. In this work, we propose a sum-of-squares based completely decentralized approach for computing the comparison systems for networks of nonlinear systems. Moreover, based on the comparison systems, we introduce a distributed optimal control strategy in which the individual subsystems (agents) coordinatemore » with their immediate neighbors to design local control policies that can exponentially stabilize the full system under initial disturbances.We illustrate the control algorithm on a network of interacting Van der Pol systems.« less

Decentralized Adaptive Neural Output-Feedback DSC for Switched Large-Scale Nonlinear Systems.

PubMed

Lijun Long; Jun Zhao

2017-04-01

In this paper, for a class of switched large-scale uncertain nonlinear systems with unknown control coefficients and unmeasurable states, a switched-dynamic-surface-based decentralized adaptive neural output-feedback control approach is developed. The approach proposed extends the classical dynamic surface control (DSC) technique for nonswitched version to switched version by designing switched first-order filters, which overcomes the problem of multiple "explosion of complexity." Also, a dual common coordinates transformation of all subsystems is exploited to avoid individual coordinate transformations for subsystems that are required when applying the backstepping recursive design scheme. Nussbaum-type functions are utilized to handle the unknown control coefficients, and a switched neural network observer is constructed to estimate the unmeasurable states. Combining with the average dwell time method and backstepping and the DSC technique, decentralized adaptive neural controllers of subsystems are explicitly designed. It is proved that the approach provided can guarantee the semiglobal uniformly ultimately boundedness for all the signals in the closed-loop system under a class of switching signals with average dwell time, and the tracking errors to a small neighborhood of the origin. A two inverted pendulums system is provided to demonstrate the effectiveness of the method proposed.

Optimal Policy of Cross-Layer Design for Channel Access and Transmission Rate Adaptation in Cognitive Radio Networks

NASA Astrophysics Data System (ADS)

He, Hao; Wang, Jun; Zhu, Jiang; Li, Shaoqian

2010-12-01

In this paper, we investigate the cross-layer design of joint channel access and transmission rate adaptation in CR networks with multiple channels for both centralized and decentralized cases. Our target is to maximize the throughput of CR network under transmission power constraint by taking spectrum sensing errors into account. In centralized case, this problem is formulated as a special constrained Markov decision process (CMDP), which can be solved by standard linear programming (LP) method. As the complexity of finding the optimal policy by LP increases exponentially with the size of action space and state space, we further apply action set reduction and state aggregation to reduce the complexity without loss of optimality. Meanwhile, for the convenience of implementation, we also consider the pure policy design and analyze the corresponding characteristics. In decentralized case, where only local information is available and there is no coordination among the CR users, we prove the existence of the constrained Nash equilibrium and obtain the optimal decentralized policy. Finally, in the case that the traffic load parameters of the licensed users are unknown for the CR users, we propose two methods to estimate the parameters for two different cases. Numerical results validate the theoretic analysis.

Multi-Agent Task Negotiation Among UAVs to Defend Against Swarm Attacks

DTIC Science & Technology

2012-03-01

are based on economic models [39]. Auction methods of task coordination also attempt to deal with agents dealing with noisy, dynamic environments...August 2006. [34] M. Alighanbari, “ Robust and decentralized task assignment algorithms for uavs,” Ph.D. dissertation, Massachusetts Institute of Technology...Implicit Coordination . . . . . . . . . . . . . 12 2.4 Decentralized Algorithm B - Market- Based . . . . . . . . . . . . . . . . 12 2.5 Decentralized

Integration of a Decentralized Linear-Quadratic-Gaussian Control into GSFC's Universal 3-D Autonomous Formation Flying Algorithm

NASA Technical Reports Server (NTRS)

Folta, David C.; Carpenter, J. Russell

1999-01-01

A decentralized control is investigated for applicability to the autonomous formation flying control algorithm developed by GSFC for the New Millenium Program Earth Observer-1 (EO-1) mission. This decentralized framework has the following characteristics: The approach is non-hierarchical, and coordination by a central supervisor is not required; Detected failures degrade the system performance gracefully; Each node in the decentralized network processes only its own measurement data, in parallel with the other nodes; Although the total computational burden over the entire network is greater than it would be for a single, centralized controller, fewer computations are required locally at each node; Requirements for data transmission between nodes are limited to only the dimension of the control vector, at the cost of maintaining a local additional data vector. The data vector compresses all past measurement history from all the nodes into a single vector of the dimension of the state; and The approach is optimal with respect to standard cost functions. The current approach is valid for linear time-invariant systems only. Similar to the GSFC formation flying algorithm, the extension to linear LQG time-varying systems requires that each node propagate its filter covariance forward (navigation) and controller Riccati matrix backward (guidance) at each time step. Extension of the GSFC algorithm to non-linear systems can also be accomplished via linearization about a reference trajectory in the standard fashion, or linearization about the current state estimate as with the extended Kalman filter. To investigate the feasibility of the decentralized integration with the GSFC algorithm, an existing centralized LQG design for a single spacecraft orbit control problem is adapted to the decentralized framework while using the GSFC algorithm's state transition matrices and framework. The existing GSFC design uses both reference trajectories of each spacecraft in formation and by appropriate choice of coordinates and simplified measurement modeling is formulated as a linear time-invariant system. Results for improvements to the GSFC algorithm and a multiple satellite formation will be addressed. The goal of this investigation is to progressively relax the assumptions that result in linear time-invariance, ultimately to the point of linearization of the non-linear dynamics about the current state estimate as in the extended Kalman filter. An assessment will then be made about the feasibility of the decentralized approach to the realistic formation flying application of the EO-1/Landsat 7 formation flying experiment.

A De-centralized Scheduling and Load Balancing Algorithm for Heterogeneous Grid Environments

NASA Technical Reports Server (NTRS)

Arora, Manish; Das, Sajal K.; Biswas, Rupak

2002-01-01

In the past two decades, numerous scheduling and load balancing techniques have been proposed for locally distributed multiprocessor systems. However, they all suffer from significant deficiencies when extended to a Grid environment: some use a centralized approach that renders the algorithm unscalable, while others assume the overhead involved in searching for appropriate resources to be negligible. Furthermore, classical scheduling algorithms do not consider a Grid node to be N-resource rich and merely work towards maximizing the utilization of one of the resources. In this paper, we propose a new scheduling and load balancing algorithm for a generalized Grid model of N-resource nodes that not only takes into account the node and network heterogeneity, but also considers the overhead involved in coordinating among the nodes. Our algorithm is decentralized, scalable, and overlaps the node coordination time with that of the actual processing of ready jobs, thus saving valuable clock cycles needed for making decisions. The proposed algorithm is studied by conducting simulations using the Message Passing Interface (MPI) paradigm.

A De-Centralized Scheduling and Load Balancing Algorithm for Heterogeneous Grid Environments

NASA Technical Reports Server (NTRS)

Arora, Manish; Das, Sajal K.; Biswas, Rupak; Biegel, Bryan (Technical Monitor)

2002-01-01

In the past two decades, numerous scheduling and load balancing techniques have been proposed for locally distributed multiprocessor systems. However, they all suffer from significant deficiencies when extended to a Grid environment: some use a centralized approach that renders the algorithm unscalable, while others assume the overhead involved in searching for appropriate resources to be negligible. Furthermore, classical scheduling algorithms do not consider a Grid node to be N-resource rich and merely work towards maximizing the utilization of one of the resources. In this paper we propose a new scheduling and load balancing algorithm for a generalized Grid model of N-resource nodes that not only takes into account the node and network heterogeneity, but also considers the overhead involved in coordinating among the nodes. Our algorithm is de-centralized, scalable, and overlaps the node coordination time of the actual processing of ready jobs, thus saving valuable clock cycles needed for making decisions. The proposed algorithm is studied by conducting simulations using the Message Passing Interface (MPI) paradigm.

On the decentralized control of large-scale systems. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Chong, C.

1973-01-01

The decentralized control of stochastic large scale systems was considered. Particular emphasis was given to control strategies which utilize decentralized information and can be computed in a decentralized manner. The deterministic constrained optimization problem is generalized to the stochastic case when each decision variable depends on different information and the constraint is only required to be satisfied on the average. For problems with a particular structure, a hierarchical decomposition is obtained. For the stochastic control of dynamic systems with different information sets, a new kind of optimality is proposed which exploits the coupled nature of the dynamic system. The subsystems are assumed to be uncoupled and then certain constraints are required to be satisfied, either in a off-line or on-line fashion. For off-line coordination, a hierarchical approach of solving the problem is obtained. The lower level problems are all uncoupled. For on-line coordination, distinction is made between open loop feedback optimal coordination and closed loop optimal coordination.

Resilience in social insect infrastructure systems

PubMed Central

2016-01-01

Both human and insect societies depend on complex and highly coordinated infrastructure systems, such as communication networks, supply chains and transportation networks. Like human-designed infrastructure systems, those of social insects are regularly subject to disruptions such as natural disasters, blockages or breaks in the transportation network, fluctuations in supply and/or demand, outbreaks of disease and loss of individuals. Unlike human-designed systems, there is no deliberate planning or centralized control system; rather, individual insects make simple decisions based on local information. How do these highly decentralized, leaderless systems deal with disruption? What factors make a social insect system resilient, and which factors lead to its collapse? In this review, we bring together literature on resilience in three key social insect infrastructure systems: transportation networks, supply chains and communication networks. We describe how systems differentially invest in three pathways to resilience: resistance, redirection or reconstruction. We suggest that investment in particular resistance pathways is related to the severity and frequency of disturbance. In the final section, we lay out a prospectus for future research. Human infrastructure networks are rapidly becoming decentralized and interconnected; indeed, more like social insect infrastructures. Human infrastructure management might therefore learn from social insect researchers, who can in turn make use of the mature analytical and simulation tools developed for the study of human infrastructure resilience. PMID:26962030

Decentralized Online Social Networks

NASA Astrophysics Data System (ADS)

Datta, Anwitaman; Buchegger, Sonja; Vu, Le-Hung; Strufe, Thorsten; Rzadca, Krzysztof

Current Online social networks (OSN) are web services run on logically centralized infrastructure. Large OSN sites use content distribution networks and thus distribute some of the load by caching for performance reasons, nevertheless there is a central repository for user and application data. This centralized nature of OSNs has several drawbacks including scalability, privacy, dependence on a provider, need for being online for every transaction, and a lack of locality. There have thus been several efforts toward decentralizing OSNs while retaining the functionalities offered by centralized OSNs. A decentralized online social network (DOSN) is a distributed system for social networking with no or limited dependency on any dedicated central infrastructure. In this chapter we explore the various motivations of a decentralized approach to online social networking, discuss several concrete proposals and types of DOSN as well as challenges and opportunities associated with decentralization.

Visualizing the Collective Learner through Decentralized Networks

ERIC Educational Resources Information Center

Castro, Juan Carlos

2015-01-01

Understandings of decentralized networks are increasingly used to describe a way to structure curriculum and pedagogy. It is often understood as a structural model to organize pedagogical and curricular relationships in which there is no center. While this is important it also bears introducing into the discourse that decentralized networks are…

Time-Coordination Strategies and Control Laws for Multi-Agent Unmanned Systems

NASA Technical Reports Server (NTRS)

Puig-Navarro, Javier; Hovakimyan, Naira; Allen, B. Danette

2017-01-01

Time-critical coordination tools for unmanned systems can be employed to enforce the type of temporal constraints required in terminal control areas, ensure minimum distance requirements among vehicles are satisfied, and successfully perform coordinated missions. In comparison with previous literature, this paper presents an ampler spectrum of coordination and temporal specifications for unmanned systems, and proposes a general control law that can enforce this range of constraints. The constraint classification presented con- siders the nature of the desired arrival window and the permissible coordination errors to define six different types of time-coordination strategies. The resulting decentralized coordination control law allows the vehicles to negotiate their speeds along their paths in response to information exchanged over the communication network. This control law organizes the different members in the fleet hierarchically per their behavior and informational needs as reference agent, leaders, and followers. Examples and simulation results for all the coordination strategies presented demonstrate the applicability and efficacy of the coordination control law for multiple unmanned systems.

Pattern Analysis in Social Networks with Dynamic Connections

NASA Astrophysics Data System (ADS)

Wu, Yu; Zhang, Yu

In this paper, we explore how decentralized local interactions of autonomous agents in a network relate to collective behaviors. Most existing work in this area models social network in which agent relations are fixed; instead, we focus on dynamic social networks where agents can rationally adjust their neighborhoods based on their individual interests. We propose a new connection evaluation rule called the Highest Weighted Reward (HWR) rule, with which agents dynamically choose their neighbors in order to maximize their own utilities based on the rewards from previous interactions. Our experiments show that in the 2-action pure coordination game, our system will stabilize to a clustering state where all relationships in the network are rewarded with the optimal payoff. Our experiments also reveal additional interesting patterns in the network.

Resilience in social insect infrastructure systems.

PubMed

Middleton, Eliza J T; Latty, Tanya

2016-03-01

Both human and insect societies depend on complex and highly coordinated infrastructure systems, such as communication networks, supply chains and transportation networks. Like human-designed infrastructure systems, those of social insects are regularly subject to disruptions such as natural disasters, blockages or breaks in the transportation network, fluctuations in supply and/or demand, outbreaks of disease and loss of individuals. Unlike human-designed systems, there is no deliberate planning or centralized control system; rather, individual insects make simple decisions based on local information. How do these highly decentralized, leaderless systems deal with disruption? What factors make a social insect system resilient, and which factors lead to its collapse? In this review, we bring together literature on resilience in three key social insect infrastructure systems: transportation networks, supply chains and communication networks. We describe how systems differentially invest in three pathways to resilience: resistance, redirection or reconstruction. We suggest that investment in particular resistance pathways is related to the severity and frequency of disturbance. In the final section, we lay out a prospectus for future research. Human infrastructure networks are rapidly becoming decentralized and interconnected; indeed, more like social insect infrastructures. Human infrastructure management might therefore learn from social insect researchers, who can in turn make use of the mature analytical and simulation tools developed for the study of human infrastructure resilience. © 2016 The Author(s).

A two-level discount model for coordinating a decentralized supply chain considering stochastic price-sensitive demand

NASA Astrophysics Data System (ADS)

Heydari, Jafar; Norouzinasab, Yousef

2015-12-01

In this paper, a discount model is proposed to coordinate pricing and ordering decisions in a two-echelon supply chain (SC). Demand is stochastic and price sensitive while lead times are fixed. Decentralized decision making where downstream decides on selling price and order size is investigated. Then, joint pricing and ordering decisions are extracted where both members act as a single entity aim to maximize whole SC profit. Finally, a coordination mechanism based on quantity discount is proposed to coordinate both pricing and ordering decisions simultaneously. The proposed two-level discount policy can be characterized from two aspects: (1) marketing viewpoint: a retail price discount to increase the demand, and (2) operations management viewpoint: a wholesale price discount to induce the retailer to adjust its order quantity and selling price jointly. Results of numerical experiments demonstrate that the proposed policy is suitable to coordinate SC and improve the profitability of SC as well as all SC members in comparison with decentralized decision making.

Decentralized control mechanism underlying interlimb coordination of millipedes.

PubMed

Kano, Takeshi; Sakai, Kazuhiko; Yasui, Kotaro; Owaki, Dai; Ishiguro, Akio

2017-04-04

Legged animals exhibit adaptive and resilient locomotion through interlimb coordination. The long-term goal of this study is to clarify the relationship between the number of legs and the inherent decentralized control mechanism for interlimb coordination. As a preliminary step, the study focuses on millipedes as they represent the species with the greatest number of legs among various animal species. A decentralized control mechanism involving local force feedback was proposed based on the qualitative findings of behavioural experiments in which responses to the removal of part of the terrain and leg amputation were observed. The proposed mechanism was implemented in a developed millipede-like robot to demonstrate that the robot can adapt to the removal of the part of the terrain and leg amputation in a manner similar to that in behavioural experiments.

40 CFR 51.353 - Network type and program evaluation.

Code of Federal Regulations, 2013 CFR

2013-07-01

..., decentralized, or a hybrid of the two at the State's discretion, but shall be demonstrated to achieve the same... § 51.351 or 51.352 of this subpart. For decentralized programs other than those meeting the design.... (a) Presumptive equivalency. A decentralized network consisting of stations that only perform...

Mobile robotic sensors for perimeter detection and tracking.

PubMed

Clark, Justin; Fierro, Rafael

2007-02-01

Mobile robot/sensor networks have emerged as tools for environmental monitoring, search and rescue, exploration and mapping, evaluation of civil infrastructure, and military operations. These networks consist of many sensors each equipped with embedded processors, wireless communication, and motion capabilities. This paper describes a cooperative mobile robot network capable of detecting and tracking a perimeter defined by a certain substance (e.g., a chemical spill) in the environment. Specifically, the contributions of this paper are twofold: (i) a library of simple reactive motion control algorithms and (ii) a coordination mechanism for effectively carrying out perimeter-sensing missions. The decentralized nature of the methodology implemented could potentially allow the network to scale to many sensors and to reconfigure when adding/deleting sensors. Extensive simulation results and experiments verify the validity of the proposed cooperative control scheme.

ALEPH: Israel's Research Library Network: Background, Evolution, and Implications for Networking in a Small Country.

ERIC Educational Resources Information Center

Lazinger, Susan S.

1991-01-01

Describes ALEPH, the research library network in Israel, and analyzes the strengths and weaknesses of its decentralized structure. Highlights include comparisons between RLIN and ALEPH; centralized versus decentralized networks; the format of ALEPH; authority control in ALEPH; and non-Roman scripts in both networks. (16 references) (LRW)

Decentralization and central and regional coordination of health services: the case of Switzerland.

PubMed

Wyss, K; Lorenz, N

2000-01-01

As part of reforms in the health care delivery sector, decentralization is currently promoted in many countries as a means to improve performance and outcomes of national health care systems. Switzerland is an example of a country with a long-standing tradition of decentralized organization for many purposes, including health care delivery. Apart from the few aspects where the responsibility is at the federal level, it is the task of the 26 cantons to organize the provision of health services for the population of around 7 million people. This permits the system to be responsive to local priorities and interest as well as to new developments in medical and public health know-how. However, the increasing and complex difficulties of most health care delivery systems raise questions about the need for mechanisms for coordination at federal level, as well as about the equity and the effectiveness of the decentralized approach. The Swiss case shows that in a strongly decentralized system, health policy and strategy elaboration, as well as coordination mechanisms among the regional components of the system, are very hard to establish. This situation may lead to strong regional inequities in the financing of health care as well as to differences in the distribution of financial, human and material inputs into the health system. The study of the Swiss health system reveals also that, within a decentralized framework, the promotion of cost-effective interventions through a well-balanced approach towards promotional, preventive and curative services, or towards ambulatory and hospital care, is difficult to achieve, as agreements between relatively autonomous regions are difficult to obtain. Therefore, a decentralized system is not necessarily the most equitable and cost-effective way to deliver health care.

On the interaction structure of linear multi-input feedback control systems. M.S. Thesis; [problem solving, lattices (mathematics)

NASA Technical Reports Server (NTRS)

Wong, P. K.

1975-01-01

The closely-related problems of designing reliable feedback stabilization strategy and coordinating decentralized feedbacks are considered. Two approaches are taken. A geometric characterization of the structure of control interaction (and its dual) was first attempted and a concept of structural homomorphism developed based on the idea of 'similarity' of interaction pattern. The idea of finding classes of individual feedback maps that do not 'interfere' with the stabilizing action of each other was developed by identifying the structural properties of nondestabilizing and LQ-optimal feedback maps. Some known stability properties of LQ-feedback were generalized and some partial solutions were provided to the reliable stabilization and decentralized feedback coordination problems. A concept of coordination parametrization was introduced, and a scheme for classifying different modes of decentralization (information, control law computation, on-line control implementation) in control systems was developed.

A Decentralized VPN Service over Generalized Mobile Ad-Hoc Networks

NASA Astrophysics Data System (ADS)

Fujita, Sho; Shima, Keiichi; Uo, Yojiro; Esaki, Hiroshi

We present a decentralized VPN service that can be built over generalized mobile ad-hoc networks (Generalized MANETs), in which topologies can be represented as a time-varying directed multigraph. We address wireless ad-hoc networks and overlay ad-hoc networks as instances of Generalized MANETs. We first propose an architecture to operate on various kinds of networks through a single set of operations. Then, we design and implement a decentralized VPN service on the proposed architecture. Through the development and operation of a prototype system we implemented, we found that the proposed architecture makes the VPN service applicable to each instance of Generalized MANETs, and that the VPN service makes it possible for unmodified applications to operate on the networks.

A distributed database view of network tracking systems

NASA Astrophysics Data System (ADS)

Yosinski, Jason; Paffenroth, Randy

2008-04-01

In distributed tracking systems, multiple non-collocated trackers cooperate to fuse local sensor data into a global track picture. Generating this global track picture at a central location is fairly straightforward, but the single point of failure and excessive bandwidth requirements introduced by centralized processing motivate the development of decentralized methods. In many decentralized tracking systems, trackers communicate with their peers via a lossy, bandwidth-limited network in which dropped, delayed, and out of order packets are typical. Oftentimes the decentralized tracking problem is viewed as a local tracking problem with a networking twist; we believe this view can underestimate the network complexities to be overcome. Indeed, a subsequent 'oversight' layer is often introduced to detect and handle track inconsistencies arising from a lack of robustness to network conditions. We instead pose the decentralized tracking problem as a distributed database problem, enabling us to draw inspiration from the vast extant literature on distributed databases. Using the two-phase commit algorithm, a well known technique for resolving transactions across a lossy network, we describe several ways in which one may build a distributed multiple hypothesis tracking system from the ground up to be robust to typical network intricacies. We pay particular attention to the dissimilar challenges presented by network track initiation vs. maintenance and suggest a hybrid system that balances speed and robustness by utilizing two-phase commit for only track initiation transactions. Finally, we present simulation results contrasting the performance of such a system with that of more traditional decentralized tracking implementations.

Decentralized regulation of dynamic systems. [for controlling large scale linear systems

NASA Technical Reports Server (NTRS)

Chu, K. C.

1975-01-01

A special class of decentralized control problem is discussed in which the objectives of the control agents are to steer the state of the system to desired levels. Each agent is concerned about certain aspects of the state of the entire system. The state and control equations are given for linear time-invariant systems. Stability and coordination, and the optimization of decentralized control are analyzed, and the information structure design is presented.

Taming instabilities in power grid networks by decentralized control

NASA Astrophysics Data System (ADS)

Schäfer, B.; Grabow, C.; Auer, S.; Kurths, J.; Witthaut, D.; Timme, M.

2016-05-01

Renewables will soon dominate energy production in our electric power system. And yet, how to integrate renewable energy into the grid and the market is still a subject of major debate. Decentral Smart Grid Control (DSGC) was recently proposed as a robust and decentralized approach to balance supply and demand and to guarantee a grid operation that is both economically and dynamically feasible. Here, we analyze the impact of network topology by assessing the stability of essential network motifs using both linear stability analysis and basin volume for delay systems. Our results indicate that if frequency measurements are averaged over sufficiently large time intervals, DSGC enhances the stability of extended power grid systems. We further investigate whether DSGC supports centralized and/or decentralized power production and find it to be applicable to both. However, our results on cycle-like systems suggest that DSGC favors systems with decentralized production. Here, lower line capacities and lower averaging times are required compared to those with centralized production.

The Large Introductory Class as an Exercise in Organization Design.

ERIC Educational Resources Information Center

Wagner, John A., III; Van Dyne, Linn

1999-01-01

Four methods for large group instruction differ in control and coordination dimensions: (1) centralization with mutual adjustment; (2) centralization with standardization; (3) decentralization with standardization; and (4) decentralization with mutual adjustment. Other factors to consider include class size and interests of various constituencies:…

Smart Computer-Assisted Markets

NASA Astrophysics Data System (ADS)

McCabe, Kevin A.; Rassenti, Stephen J.; Smith, Vernon L.

1991-10-01

The deregulation movement has motivated the experimental study of auction markets designed for interdependent network industries such as natural gas pipelines or electric power systems. Decentralized agents submit bids to buy commodity and offers to sell transportation and commodity to a computerized dispatch center. Computer algorithms determine prices and allocations that maximize the gains from exchange in the system relative to the submitted bids and offers. The problem is important, because traditionally the scale and coordination economies in such industries were thought to require regulation. Laboratory experiments are used to study feasibility, limitations, incentives, and performance of proposed market designs for deregulation, providing motivation for new theory.

The role of human-automation consensus in multiple unmanned vehicle scheduling.

PubMed

Cummings, M L; Clare, Andrew; Hart, Christin

2010-02-01

This study examined the impact of increasing automation replanning rates on operator performance and workload when supervising a decentralized network of heterogeneous unmanned vehicles. Futuristic unmanned vehicles systems will invert the operator-to-vehicle ratio so that one operator can control multiple dissimilar vehicles connected through a decentralized network. Significant human-automation collaboration will be needed because of automation brittleness, but such collaboration could cause high workload. Three increasing levels of replanning were tested on an existing multiple unmanned vehicle simulation environment that leverages decentralized algorithms for vehicle routing and task allocation in conjunction with human supervision. Rapid replanning can cause high operator workload, ultimately resulting in poorer overall system performance. Poor performance was associated with a lack of operator consensus for when to accept the automation's suggested prompts for new plan consideration as well as negative attitudes toward unmanned aerial vehicles in general. Participants with video game experience tended to collaborate more with the automation, which resulted in better performance. In decentralized unmanned vehicle networks, operators who ignore the automation's requests for new plan consideration and impose rapid replans both increase their own workload and reduce the ability of the vehicle network to operate at its maximum capacity. These findings have implications for personnel selection and training for futuristic systems involving human collaboration with decentralized algorithms embedded in networks of autonomous systems.

The Impact of Human-Automation Collaboration in Decentralized Multiple Unmanned Vehicle Control

DTIC Science & Technology

2011-01-01

based decentralized auctions for robust task allocation ,[ IEEE Trans. Robot., vol. 25, no. 4, pp...operators can aid such systems by bringing their knowledge- based reasoning and experience to bear. Given a decentralized task planner and a goal- based ...experience to bear. Given a decentralized task planner and a goal- based operator interface for a network of unmanned vehicles in a search, track,

Decentralization or centralization: striking a balance.

PubMed

Dirschel, K M

1994-09-01

An Executive Vice President for Nursing can provide the necessary link to meet diverse clinical demands when encountering centralization--decentralization decisions. Centralized communication links hospital departments giving nurses a unified voice. Decentralization acknowledges the need for diversity and achieves the right balance of uniformity through a responsive communications network.

Centralized and decentralized global outer-synchronization of asymmetric recurrent time-varying neural network by data-sampling.

PubMed

Lu, Wenlian; Zheng, Ren; Chen, Tianping

2016-03-01

In this paper, we discuss outer-synchronization of the asymmetrically connected recurrent time-varying neural networks. By using both centralized and decentralized discretization data sampling principles, we derive several sufficient conditions based on three vector norms to guarantee that the difference of any two trajectories starting from different initial values of the neural network converges to zero. The lower bounds of the common time intervals between data samples in centralized and decentralized principles are proved to be positive, which guarantees exclusion of Zeno behavior. A numerical example is provided to illustrate the efficiency of the theoretical results. Copyright © 2015 Elsevier Ltd. All rights reserved.

Decision and coordination of low-carbon supply chain considering technological spillover and environmental awareness.

PubMed

Xu, Lang; Wang, Chuanxu; Li, Hui

2017-06-08

We focus on the impacts of technological spillovers and environmental awareness in a two-echelon supply chain with one-single supplier and one-single manufacturer to reduce carbon emission. In this supply chain, carbon abatement investment becomes one of key factors of cutting costs and improving profits, which is reducing production costs in the components and products-the investment from players in supply chain. On the basis of optimality theory, the centralized and decentralized models are respectively established to investigate the optimal decisions and profits. Further, setting the players' profits of the decentralized scenario as the disagreement points, we propose a bargaining-coordination contract through revenue-cost sharing to enhance the performance. Finally, by theoretical comparison and numerical analysis, the results show that: (i) The optimal profits of players and supply chain improve as technological spillovers and environmental awareness increase, and the profits of them in the bargaining-coordination contract are higher than that in the decentralized scenario; (ii) Technological spillovers between the players amplify the impact of "free-ride" behavior, in which the supplier always incentives the manufacturer to improve carbon emission intensity, but the cooperation will achieves and the profits will improve only when technological spillovers and environmental awareness are great; (iii) The contract can effectively achieve coordinated supply chain, and improve carbon abatement investment.

Distributed and cooperative task processing: Cournot oligopolies on a graph.

PubMed

Pavlic, Theodore P; Passino, Kevin M

2014-06-01

This paper introduces a novel framework for the design of distributed agents that must complete externally generated tasks but also can volunteer to process tasks encountered by other agents. To reduce the computational and communication burden of coordination between agents to perfectly balance load around the network, the agents adjust their volunteering propensity asynchronously within a fictitious trading economy. This economy provides incentives for nontrivial levels of volunteering for remote tasks, and thus load is shared. Moreover, the combined effects of diminishing marginal returns and network topology lead to competitive equilibria that have task reallocations that are qualitatively similar to what is expected in a load-balancing system with explicit coordination between nodes. In the paper, topological and algorithmic conditions are given that ensure the existence and uniqueness of a competitive equilibrium. Additionally, a decentralized distributed gradient-ascent algorithm is given that is guaranteed to converge to this equilibrium while not causing any node to over-volunteer beyond its maximum task-processing rate. The framework is applied to an autonomous-air-vehicle example, and connections are drawn to classic studies of the evolution of cooperation in nature.

A decentralized mechanism for improving the functional robustness of distribution networks.

PubMed

Shi, Benyun; Liu, Jiming

2012-10-01

Most real-world distribution systems can be modeled as distribution networks, where a commodity can flow from source nodes to sink nodes through junction nodes. One of the fundamental characteristics of distribution networks is the functional robustness, which reflects the ability of maintaining its function in the face of internal or external disruptions. In view of the fact that most distribution networks do not have any centralized control mechanisms, we consider the problem of how to improve the functional robustness in a decentralized way. To achieve this goal, we study two important problems: 1) how to formally measure the functional robustness, and 2) how to improve the functional robustness of a network based on the local interaction of its nodes. First, we derive a utility function in terms of network entropy to characterize the functional robustness of a distribution network. Second, we propose a decentralized network pricing mechanism, where each node need only communicate with its distribution neighbors by sending a "price" signal to its upstream neighbors and receiving "price" signals from its downstream neighbors. By doing so, each node can determine its outflows by maximizing its own payoff function. Our mathematical analysis shows that the decentralized pricing mechanism can produce results equivalent to those of an ideal centralized maximization with complete information. Finally, to demonstrate the properties of our mechanism, we carry out a case study on the U.S. natural gas distribution network. The results validate the convergence and effectiveness of our mechanism when comparing it with an existing algorithm.

Quality control and improvement of cancer care: what is needed? 4th European Roundtable Meeting (ERTM) May 5th, 2017, Berlin, Germany.

PubMed

Ortmann, Olaf; Helbig, Ulrike; Torode, Julie; Schreck, Stefan; Karjalainen, Sakari; Bettio, Manola; Ringborg, Ulrik; Klinkhammer-Schalke, Monika; Bray, Freddy

2018-06-01

National Cancer Control Plans (NCCPs) often describe structural requirements for high quality cancer care. During the fourth European Roundtable Meeting (ERTM) participants shared learnings from their own national setting to formulate best practice in optimizing communication strategies between parties involved in clinical cancer registries, cancer centers and guideline groups. A decentralized model of data collection close to the patient and caregiver enhances timely completion and the quality of the data captured. Nevertheless, central coordination is necessary to define datasets, indicators, standard settings, education, training and quality control to maintain standards across the network. In particular, interaction of parties in cancer care network has to be established and maintained on a regular basis. After establishing the structural requirements of cancer care networks, communication between the different components and parties is required to analyze outcome data, provide regular reporting to all and develop strategies for continuous improvement of quality across the network.

Coordinated Collaboration between Heterogeneous Distributed Energy Resources

DOE PAGES

Abdollahy, Shahin; Lavrova, Olga; Mammoli, Andrea

2014-01-01

A power distribution feeder, where a heterogeneous set of distributed energy resources is deployed, is examined by simulation. The energy resources include PV, battery storage, natural gas GenSet, fuel cells, and active thermal storage for commercial buildings. The resource scenario considered is one that may exist in a not too distant future. Two cases of interaction between different resources are examined. One interaction involves a GenSet used to partially offset the duty cycle of a smoothing battery connected to a large PV system. The other example involves the coordination of twenty thermal storage devices, each associated with a commercial building.more » Storage devices are intended to provide maximum benefit to the building, but it is shown that this can have a deleterious effect on the overall system, unless the action of the individual storage devices is coordinated. A network based approach is also introduced to calculate some type of effectiveness metric to all available resources which take part in coordinated operation. The main finding is that it is possible to achieve synergy between DERs on a system; however this required a unified strategy to coordinate the action of all devices in a decentralized way.« less

Recycling Pricing and Coordination of WEEE Dual-Channel Closed-Loop Supply Chain Considering Consumers' Bargaining.

PubMed

Zhu, Xiaodong; Wang, Jing; Tang, Juan

2017-12-15

Environmentally friendly handling and efficient recycling of waste electrical on Waste Electrical and Electronic Equipment (WEEE) have grown to be a global social problem. As holders of WEEE, consumers have a significant effect on the recycling process. A consideration of and attention to the influence of consumer behavior in the recycling process can help achieve more effective recycling of WEEE. In this paper, we built a dual-channel closed-loop supply chain model composed of manufacturers, retailers, and network recycling platforms. Based on the influence of customer bargaining behavior, we studied several different scenarios of centralized decision-making, decentralized decision-making, and contract coordination, using the Stackelberg game theory. The results show that retailers and network recycling platforms will reduce the direct recovery prices to maintain their own profit when considering the impact of consumer bargaining behavior, while remanufacturers will improve the transfer payment price for surrendering part of the profit under revenue and the expense sharing contract. Using this contract, we can achieve supply chain coordination and eliminate the effect of consumer bargaining behavior on supply chain performance. It can be viewed from the parameter sensitivity analysis that when we select the appropriate sharing coefficient, the closed-loop supply chain can achieve the same system performance under a centralized decision.

Recycling Pricing and Coordination of WEEE Dual-Channel Closed-Loop Supply Chain Considering Consumers’ Bargaining

PubMed Central

Zhu, Xiaodong; Wang, Jing; Tang, Juan

2017-01-01

Environmentally friendly handling and efficient recycling of waste electrical on Waste Electrical and Electronic Equipment (WEEE) have grown to be a global social problem. As holders of WEEE, consumers have a significant effect on the recycling process. A consideration of and attention to the influence of consumer behavior in the recycling process can help achieve more effective recycling of WEEE. In this paper, we built a dual-channel closed-loop supply chain model composed of manufacturers, retailers, and network recycling platforms. Based on the influence of customer bargaining behavior, we studied several different scenarios of centralized decision-making, decentralized decision-making, and contract coordination, using the Stackelberg game theory. The results show that retailers and network recycling platforms will reduce the direct recovery prices to maintain their own profit when considering the impact of consumer bargaining behavior, while remanufacturers will improve the transfer payment price for surrendering part of the profit under revenue and the expense sharing contract. Using this contract, we can achieve supply chain coordination and eliminate the effect of consumer bargaining behavior on supply chain performance. It can be viewed from the parameter sensitivity analysis that when we select the appropriate sharing coefficient, the closed-loop supply chain can achieve the same system performance under a centralized decision. PMID:29244778

Adaptive neural network decentralized backstepping output-feedback control for nonlinear large-scale systems with time delays.

PubMed

Tong, Shao Cheng; Li, Yong Ming; Zhang, Hua-Guang

2011-07-01

In this paper, two adaptive neural network (NN) decentralized output feedback control approaches are proposed for a class of uncertain nonlinear large-scale systems with immeasurable states and unknown time delays. Using NNs to approximate the unknown nonlinear functions, an NN state observer is designed to estimate the immeasurable states. By combining the adaptive backstepping technique with decentralized control design principle, an adaptive NN decentralized output feedback control approach is developed. In order to overcome the problem of "explosion of complexity" inherent in the proposed control approach, the dynamic surface control (DSC) technique is introduced into the first adaptive NN decentralized control scheme, and a simplified adaptive NN decentralized output feedback DSC approach is developed. It is proved that the two proposed control approaches can guarantee that all the signals of the closed-loop system are semi-globally uniformly ultimately bounded, and the observer errors and the tracking errors converge to a small neighborhood of the origin. Simulation results are provided to show the effectiveness of the proposed approaches.

Model-Based Design of Tree WSNs for Decentralized Detection.

PubMed

Tantawy, Ashraf; Koutsoukos, Xenofon; Biswas, Gautam

2015-08-20

The classical decentralized detection problem of finding the optimal decision rules at the sensor and fusion center, as well as variants that introduce physical channel impairments have been studied extensively in the literature. The deployment of WSNs in decentralized detection applications brings new challenges to the field. Protocols for different communication layers have to be co-designed to optimize the detection performance. In this paper, we consider the communication network design problem for a tree WSN. We pursue a system-level approach where a complete model for the system is developed that captures the interactions between different layers, as well as different sensor quality measures. For network optimization, we propose a hierarchical optimization algorithm that lends itself to the tree structure, requiring only local network information. The proposed design approach shows superior performance over several contentionless and contention-based network design approaches.

Ecology Based Decentralized Agent Management System

NASA Technical Reports Server (NTRS)

Peysakhov, Maxim D.; Cicirello, Vincent A.; Regli, William C.

2004-01-01

The problem of maintaining a desired number of mobile agents on a network is not trivial, especially if we want a completely decentralized solution. Decentralized control makes a system more r e bust and less susceptible to partial failures. The problem is exacerbated on wireless ad hoc networks where host mobility can result in significant changes in the network size and topology. In this paper we propose an ecology-inspired approach to the management of the number of agents. The approach associates agents with living organisms and tasks with food. Agents procreate or die based on the abundance of uncompleted tasks (food). We performed a series of experiments investigating properties of such systems and analyzed their stability under various conditions. We concluded that the ecology based metaphor can be successfully applied to the management of agent populations on wireless ad hoc networks.

From social network (centralized vs. decentralized) to collective decision-making (unshared vs. shared consensus).

PubMed

Sueur, Cédric; Deneubourg, Jean-Louis; Petit, Odile

2012-01-01

Relationships we have with our friends, family, or colleagues influence our personal decisions, as well as decisions we make together with others. As in human beings, despotism and egalitarian societies seem to also exist in animals. While studies have shown that social networks constrain many phenomena from amoebae to primates, we still do not know how consensus emerges from the properties of social networks in many biological systems. We created artificial social networks that represent the continuum from centralized to decentralized organization and used an agent-based model to make predictions about the patterns of consensus and collective movements we observed according to the social network. These theoretical results showed that different social networks and especially contrasted ones--star network vs. equal network--led to totally different patterns. Our model showed that, by moving from a centralized network to a decentralized one, the central individual seemed to lose its leadership in the collective movement's decisions. We, therefore, showed a link between the type of social network and the resulting consensus. By comparing our theoretical data with data on five groups of primates, we confirmed that this relationship between social network and consensus also appears to exist in animal societies.

Analyzing the effects of transit network change on agency performance and riders in a decentralized, small-to-mid-sized US metropolitan area : a case study of Tallahassee, Florida.

DOT National Transportation Integrated Search

2013-05-01

On July 11, 2011, StarMetro, the local public transit agency in Tallahassee, Florida, restructured its entire bus network from a : downtown-focused radial system to a decentralized, grid-like system that local officials and agency leaders believed wo...

Decentralized stabilization for a class of continuous-time nonlinear interconnected systems using online learning optimal control approach.

PubMed

Liu, Derong; Wang, Ding; Li, Hongliang

2014-02-01

In this paper, using a neural-network-based online learning optimal control approach, a novel decentralized control strategy is developed to stabilize a class of continuous-time nonlinear interconnected large-scale systems. First, optimal controllers of the isolated subsystems are designed with cost functions reflecting the bounds of interconnections. Then, it is proven that the decentralized control strategy of the overall system can be established by adding appropriate feedback gains to the optimal control policies of the isolated subsystems. Next, an online policy iteration algorithm is presented to solve the Hamilton-Jacobi-Bellman equations related to the optimal control problem. Through constructing a set of critic neural networks, the cost functions can be obtained approximately, followed by the control policies. Furthermore, the dynamics of the estimation errors of the critic networks are verified to be uniformly and ultimately bounded. Finally, a simulation example is provided to illustrate the effectiveness of the present decentralized control scheme.

Coordination of Distributed Fuzzy Behaviors in Mobile Robot Control

NASA Technical Reports Server (NTRS)

Tunstel, E.

1995-01-01

This presentation describes an approach to behavior coordination and conflict resolution within the context of a hierarchical architecture of fuzzy behaviors. Coordination is achieved using weighted decision-making based on behavioral degrees of applicability. This strategy is appropriate for fuzzy control of systems that can be represented by hierarchical or decentralized structures.

Taking stock of decentralized disaster risk reduction in Indonesia

NASA Astrophysics Data System (ADS)

Grady, Anthony; Gersonius, Berry; Makarigakis, Alexandros

2016-09-01

The Sendai Framework, which outlines the global course on disaster risk reduction until 2030, places strong importance on the role of local government in disaster risk reduction. An aim of decentralization is to increase the influence and authority of local government in decision making. Yet, there is limited empirical evidence of the extent, character and effects of decentralization in current disaster risk reduction implementation, and of the barriers that are most critical to this. This paper evaluates decentralization in relation to disaster risk reduction in Indonesia, chosen for its recent actions to decentralize governance of DRR coupled with a high level of disaster risk. An analytical framework was developed to evaluate the various dimensions of decentralized disaster risk reduction, which necessitated the use of a desk study, semi-structured interviews and a gap analysis. Key barriers to implementation in Indonesia included: capacity gaps at lower institutional levels, low compliance with legislation, disconnected policies, issues in communication and coordination and inadequate resourcing. However, any of these barriers are not unique to disaster risk reduction, and similar barriers have been observed for decentralization in other developing countries in other public sectors.

Research on Coordination of Fresh Produce Supply Chain in Big Market Sales Environment

PubMed Central

Su, Juning; Liu, Chenguang

2014-01-01

In this paper, we propose two decision models for decentralized and centralized fresh produce supply chains with stochastic supply and demand and controllable transportation time. The optimal order quantity and the optimal transportation time in these two supply chain systems are derived. To improve profits in a decentralized supply chain, based on analyzing the risk taken by each participant in the supply chain, we design a set of contracts which can coordinate this type of fresh produce supply chain with stochastic supply and stochastic demand, and controllable transportation time as well. We also obtain a value range of contract parameters that can increase profits of all participants in the decentralized supply chain. The expected profits of the decentralized setting and the centralized setting are compared with respect to given numerical examples. Furthermore, the sensitivity analyses of the deterioration rate factor and the freshness factor are performed. The results of numerical examples show that the transportation time is shorter, the order quantity is smaller, the total profit of whole supply chain is less, and the possibility of cooperation between supplier and retailer is higher for the fresh produce which is more perishable and its quality decays more quickly. PMID:24764770

Research on coordination of fresh produce supply chain in big market sales environment.

PubMed

Su, Juning; Wu, Jiebing; Liu, Chenguang

2014-01-01

In this paper, we propose two decision models for decentralized and centralized fresh produce supply chains with stochastic supply and demand and controllable transportation time. The optimal order quantity and the optimal transportation time in these two supply chain systems are derived. To improve profits in a decentralized supply chain, based on analyzing the risk taken by each participant in the supply chain, we design a set of contracts which can coordinate this type of fresh produce supply chain with stochastic supply and stochastic demand, and controllable transportation time as well. We also obtain a value range of contract parameters that can increase profits of all participants in the decentralized supply chain. The expected profits of the decentralized setting and the centralized setting are compared with respect to given numerical examples. Furthermore, the sensitivity analyses of the deterioration rate factor and the freshness factor are performed. The results of numerical examples show that the transportation time is shorter, the order quantity is smaller, the total profit of whole supply chain is less, and the possibility of cooperation between supplier and retailer is higher for the fresh produce which is more perishable and its quality decays more quickly.

Self-control of traffic lights and vehicle flows in urban road networks

NASA Astrophysics Data System (ADS)

Lämmer, Stefan; Helbing, Dirk

2008-04-01

Based on fluid-dynamic and many-particle (car-following) simulations of traffic flows in (urban) networks, we study the problem of coordinating incompatible traffic flows at intersections. Inspired by the observation of self-organized oscillations of pedestrian flows at bottlenecks, we propose a self-organization approach to traffic light control. The problem can be treated as a multi-agent problem with interactions between vehicles and traffic lights. Specifically, our approach assumes a priority-based control of traffic lights by the vehicle flows themselves, taking into account short-sighted anticipation of vehicle flows and platoons. The considered local interactions lead to emergent coordination patterns such as 'green waves' and achieve an efficient, decentralized traffic light control. While the proposed self-control adapts flexibly to local flow conditions and often leads to non-cyclical switching patterns with changing service sequences of different traffic flows, an almost periodic service may evolve under certain conditions and suggests the existence of a spontaneous synchronization of traffic lights despite the varying delays due to variable vehicle queues and travel times. The self-organized traffic light control is based on an optimization and a stabilization rule, each of which performs poorly at high utilizations of the road network, while their proper combination reaches a superior performance. The result is a considerable reduction not only in the average travel times, but also of their variation. Similar control approaches could be applied to the coordination of logistic and production processes.

Decentralized coordinated control of elastic web winding systems without tension sensor.

PubMed

Hou, Hailiang; Nian, Xiaohong; Chen, Jie; Xiao, Dengfeng

2018-06-26

In elastic web winding systems, precise regulation of web tension in each span is critical to ensure final product quality, and to achieve low cost by reducing the occurrence of web break or fold. Generally, web winding systems use load cells or swing rolls as tension sensors, which add cost, reduce system reliability and increase the difficulty of control. In this paper, a decentralized coordinated control scheme with tension observers is designed for a three-motor web-winding system. First, two tension observers are proposed to estimate the unwinding and winding tension. The designed observers consider the essential dynamic, radius, and inertial variation effects and only require the modest computational effort. Then, using the estimated tensions as feedback signals, a robust decentralized coordinated controller is adopted to reduce the interaction between subsystems. Asymptotic stabilities of the observer error dynamics and the closed-loop winding systems are demonstrated via Lyapunov stability theory. The observer gains and the controller gains can be obtained by solving matrix inequalities. Finally, some simulations and experiments are performed on a paper winding setup to test the performance of the designed observers and the observer-base DCC method, respectively. Copyright © 2018 ISA. Published by Elsevier Ltd. All rights reserved.

Value Driven Information Processing and Fusion

DTIC Science & Technology

2016-03-01

consensus approach allows a decentralized approach to achieve the optimal error exponent of the centralized counterpart, a conclusion that is signifi...SECURITY CLASSIFICATION OF: The objective of the project is to develop a general framework for value driven decentralized information processing...including: optimal data reduction in a network setting for decentralized inference with quantization constraint; interactive fusion that allows queries and

A web-based information system for a regional public mental healthcare service network in Brazil.

PubMed

Yoshiura, Vinicius Tohoru; de Azevedo-Marques, João Mazzoncini; Rzewuska, Magdalena; Vinci, André Luiz Teixeira; Sasso, Ariane Morassi; Miyoshi, Newton Shydeo Brandão; Furegato, Antonia Regina Ferreira; Rijo, Rui Pedro Charters Lopes; Del-Ben, Cristina Marta; Alves, Domingos

2017-01-01

Regional networking between services that provide mental health care in Brazil's decentralized public health system is challenging, partly due to the simultaneous existence of services managed by municipal and state authorities and a lack of efficient and transparent mechanisms for continuous and updated communication between them. Since 2011, the Ribeirao Preto Medical School and the XIII Regional Health Department of the Sao Paulo state, Brazil, have been developing and implementing a web-based information system to facilitate an integrated care throughout a public regional mental health care network. After a profound on-site analysis, the structure of the network was identified and a web-based information system for psychiatric admissions and discharges was developed and implemented using a socio-technical approach. An information technology team liaised with mental health professionals, health-service managers, municipal and state health secretariats and judicial authorities. Primary care, specialized community services, general emergency and psychiatric wards services, that comprise the regional mental healthcare network, were identified and the system flow was delineated. The web-based system overcame the fragmentation of the healthcare system and addressed service specific needs, enabling: detailed patient information sharing; active coordination of the processes of psychiatric admissions and discharges; real-time monitoring; the patients' status reports; the evaluation of the performance of each service and the whole network. During a 2-year period of operation, it registered 137 services, 480 health care professionals and 4271 patients, with a mean number of 2835 accesses per month. To date the system is successfully operating and further expanding. We have successfully developed and implemented an acceptable, useful and transparent web-based information system for a regional mental healthcare service network in a medium-income country with a decentralized public health system. Systematic collaboration between an information technology team and a wide range of stakeholders is essential for the system development and implementation.

Model-Based Design of Tree WSNs for Decentralized Detection †

PubMed Central

Tantawy, Ashraf; Koutsoukos, Xenofon; Biswas, Gautam

2015-01-01

The classical decentralized detection problem of finding the optimal decision rules at the sensor and fusion center, as well as variants that introduce physical channel impairments have been studied extensively in the literature. The deployment of WSNs in decentralized detection applications brings new challenges to the field. Protocols for different communication layers have to be co-designed to optimize the detection performance. In this paper, we consider the communication network design problem for a tree WSN. We pursue a system-level approach where a complete model for the system is developed that captures the interactions between different layers, as well as different sensor quality measures. For network optimization, we propose a hierarchical optimization algorithm that lends itself to the tree structure, requiring only local network information. The proposed design approach shows superior performance over several contentionless and contention-based network design approaches. PMID:26307989

Decentralized Feedback Controllers for Exponential Stabilization of Hybrid Periodic Orbits: Application to Robotic Walking.

PubMed

Hamed, Kaveh Akbari; Gregg, Robert D

2016-07-01

This paper presents a systematic algorithm to design time-invariant decentralized feedback controllers to exponentially stabilize periodic orbits for a class of hybrid dynamical systems arising from bipedal walking. The algorithm assumes a class of parameterized and nonlinear decentralized feedback controllers which coordinate lower-dimensional hybrid subsystems based on a common phasing variable. The exponential stabilization problem is translated into an iterative sequence of optimization problems involving bilinear and linear matrix inequalities, which can be easily solved with available software packages. A set of sufficient conditions for the convergence of the iterative algorithm to a stabilizing decentralized feedback control solution is presented. The power of the algorithm is demonstrated by designing a set of local nonlinear controllers that cooperatively produce stable walking for a 3D autonomous biped with 9 degrees of freedom, 3 degrees of underactuation, and a decentralization scheme motivated by amputee locomotion with a transpelvic prosthetic leg.

Decentralized Feedback Controllers for Exponential Stabilization of Hybrid Periodic Orbits: Application to Robotic Walking*

PubMed Central

Hamed, Kaveh Akbari; Gregg, Robert D.

2016-01-01

This paper presents a systematic algorithm to design time-invariant decentralized feedback controllers to exponentially stabilize periodic orbits for a class of hybrid dynamical systems arising from bipedal walking. The algorithm assumes a class of parameterized and nonlinear decentralized feedback controllers which coordinate lower-dimensional hybrid subsystems based on a common phasing variable. The exponential stabilization problem is translated into an iterative sequence of optimization problems involving bilinear and linear matrix inequalities, which can be easily solved with available software packages. A set of sufficient conditions for the convergence of the iterative algorithm to a stabilizing decentralized feedback control solution is presented. The power of the algorithm is demonstrated by designing a set of local nonlinear controllers that cooperatively produce stable walking for a 3D autonomous biped with 9 degrees of freedom, 3 degrees of underactuation, and a decentralization scheme motivated by amputee locomotion with a transpelvic prosthetic leg. PMID:27990059

Decentralized control

NASA Technical Reports Server (NTRS)

Steffen, Chris

1990-01-01

An overview of the time-delay problem and the reliability problem which arise in trying to perform robotic construction operations at a remote space location are presented. The effects of the time-delay upon the control system design will be itemized. A high level overview of a decentralized method of control which is expected to perform better than the centralized approach in solving the time-delay problem is given. The lower level, decentralized, autonomous, Troter Move-Bar algorithm is also presented (Troters are coordinated independent robots). The solution of the reliability problem is connected to adding redundancy to the system. One method of adding redundancy is given.

Optimizing decentralized production-distribution planning problem in a multi-period supply chain network under uncertainty

NASA Astrophysics Data System (ADS)

Nourifar, Raheleh; Mahdavi, Iraj; Mahdavi-Amiri, Nezam; Paydar, Mohammad Mahdi

2017-09-01

Decentralized supply chain management is found to be significantly relevant in today's competitive markets. Production and distribution planning is posed as an important optimization problem in supply chain networks. Here, we propose a multi-period decentralized supply chain network model with uncertainty. The imprecision related to uncertain parameters like demand and price of the final product is appropriated with stochastic and fuzzy numbers. We provide mathematical formulation of the problem as a bi-level mixed integer linear programming model. Due to problem's convolution, a structure to solve is developed that incorporates a novel heuristic algorithm based on Kth-best algorithm, fuzzy approach and chance constraint approach. Ultimately, a numerical example is constructed and worked through to demonstrate applicability of the optimization model. A sensitivity analysis is also made.

Optimizing Natural Gas Networks through Dynamic Manifold Theory and a Decentralized Algorithm: Belgium Case Study

NASA Astrophysics Data System (ADS)

Koch, Caleb; Winfrey, Leigh

2014-10-01

Natural Gas is a major energy source in Europe, yet political instabilities have the potential to disrupt access and supply. Energy resilience is an increasingly essential construct and begins with transmission network design. This study proposes a new way of thinking about modelling natural gas flow. Rather than relying on classical economic models, this problem is cast into a time-dependent Hamiltonian dynamics discussion. Traditional Natural Gas constraints, including inelastic demand and maximum/minimum pipe flows, are portrayed as energy functions and built into the dynamics of each pipe flow. Doing so allows the constraints to be built into the dynamics of each pipeline. As time progresses in the model, natural gas flow rates find the minimum energy, thus the optimal gas flow rates. The most important result of this study is using dynamical principles to ensure the output of natural gas at demand nodes remains constant, which is important for country to country natural gas transmission. Another important step in this study is building the dynamics of each flow in a decentralized algorithm format. Decentralized regulation has solved congestion problems for internet data flow, traffic flow, epidemiology, and as demonstrated in this study can solve the problem of Natural Gas congestion. A mathematical description is provided for how decentralized regulation leads to globally optimized network flow. Furthermore, the dynamical principles and decentralized algorithm are applied to a case study of the Fluxys Belgium Natural Gas Network.

From Social Network (Centralized vs. Decentralized) to Collective Decision-Making (Unshared vs. Shared Consensus)

PubMed Central

Sueur, Cédric; Deneubourg, Jean-Louis; Petit, Odile

2012-01-01

Relationships we have with our friends, family, or colleagues influence our personal decisions, as well as decisions we make together with others. As in human beings, despotism and egalitarian societies seem to also exist in animals. While studies have shown that social networks constrain many phenomena from amoebae to primates, we still do not know how consensus emerges from the properties of social networks in many biological systems. We created artificial social networks that represent the continuum from centralized to decentralized organization and used an agent-based model to make predictions about the patterns of consensus and collective movements we observed according to the social network. These theoretical results showed that different social networks and especially contrasted ones – star network vs. equal network - led to totally different patterns. Our model showed that, by moving from a centralized network to a decentralized one, the central individual seemed to lose its leadership in the collective movement's decisions. We, therefore, showed a link between the type of social network and the resulting consensus. By comparing our theoretical data with data on five groups of primates, we confirmed that this relationship between social network and consensus also appears to exist in animal societies. PMID:22393416

Analysis of electric power industry restructuring

NASA Astrophysics Data System (ADS)

Al-Agtash, Salem Yahya

1998-10-01

This thesis evaluates alternative structures of the electric power industry in a competitive environment. One structure is based on the principle of creating a mandatory power pool to foster competition and manage system economics. The structure is PoolCo (pool coordination). A second structure is based on the principle of allowing independent multilateral trading and decentralized market coordination. The structure is DecCo (decentralized coordination). The criteria I use to evaluate these two structures are: economic efficiency, system reliability and freedom of choice. Economic efficiency evaluation considers strategic behavior of individual generators as well as behavioral variations of different classes of consumers. A supply-function equilibria model is characterized for deriving bidding strategies of competing generators under PoolCo. It is shown that asymmetric equilibria can exist within the capacities of generators. An augmented Lagrangian approach is introduced to solve iteratively for global optimal operations schedules. Under DecCo, the process involves solving iteratively for system operations schedules. The schedules reflect generators strategic behavior and brokers' interactions for arranging profitable trades, allocating losses and managing network congestion. In the determination of PoolCo and DecCo operations schedules, overall costs of power generation (start-up and shut-down costs and availability of hydro electric power) as well as losses and costs of transmission network are considered. For system reliability evaluation, I examine the effect of PoolCo and DecCo operating conditions on the system security. Random component failure perturbations are generated to simulate the actual system behavior. This is done using Monte Carlo simulation. Freedom of choice evaluation accounts for schemes' beneficial opportunities and capabilities to respond to consumers expressed preferences. An IEEE 24-bus test system is used to illustrate the concepts developed for economic efficiency evaluation. The system was tested over two years time period. The results indicate 2.6684 and 2.7269 percent of efficiency loss on average for PoolCo and DecCo, respectively. These values, however, do not represent forecasts of efficiency losses of PoolCo- and DecCo-based competitive industries. Rather, they are illustrations of the efficiency losses for the given IEEE test system and based on the modeling assumptions underlying framework development.

The coordination of problem solving strategies: when low competence sources exert more influence on task processing than high competence sources.

PubMed

Quiamzade, Alain; Mugny, Gabriel; Darnon, Céline

2009-03-01

Previous research has shown that low competence sources, compared to highly competent sources, can exert influence in aptitudes tasks in as much as they induce people to focus on the task and to solve it more deeply. Two experiments aimed at testing the coordination between self and source's problem solving strategies as a main explanation of such a difference in influence. The influence of a low versus high competence source has been examined in an anagram task that allows for distinguishing between three response strategies, including one that corresponds to the coordination between the source's strategy and participants' own strategy. In Study 1 the strategy suggested by the source was either relevant and useful or irrelevant and useless for solving the task. Results indicated that participants used the coordination strategy in a larger extend when they had been confronted to a low competence rather than a highly competent source but only when the source displayed a strategy that was useful to solve the task. In Study 2 the source's strategy was always relevant and useful, but a decentring procedure was introduced for half of the participants. This procedure induced participants to consider other points of view than their own. Results replicated the difference observed in Study 1 when no decentring was introduced. The difference however disappeared when decentring was induced, because of an increase of the high competence source's influence. These results highlight coordination of strategies as one mechanism underlying influence from low competence sources.

Energy-efficient pulse-coupled synchronization strategy design for wireless sensor networks through reduced idle listening

PubMed Central

Wang, Yongqiang; Núñez, Felipe; Doyle, Francis J.

2013-01-01

Synchronization is crucial to wireless sensor networks due to their decentralized structure. We propose an energy-efficient pulse-coupled synchronization strategy to achieve this goal. The basic idea is to reduce idle listening by intentionally introducing a large refractory period in the sensors’ cooperation. The large refractory period greatly reduces idle listening in each oscillation period, and is analytically proven to have no influence on the time to synchronization. Hence, it significantly reduces the total energy consumption in a synchronization process. A topology control approach tailored for pulse-coupled synchronization is given to guarantee a k-edge strongly connected interaction topology, which is tolerant to communication-link failures. The topology control approach is totally decentralized and needs no information exchange among sensors, and it is applicable to dynamic network topologies as well. This facilitates a completely decentralized implementation of the synchronization strategy. The strategy is applicable to mobile sensor networks, too. QualNet case studies confirm the effectiveness of the synchronization strategy. PMID:24307831

Decentralized Patrolling Under Constraints in Dynamic Environments.

PubMed

Shaofei Chen; Feng Wu; Lincheng Shen; Jing Chen; Ramchurn, Sarvapali D

2016-12-01

We investigate a decentralized patrolling problem for dynamic environments where information is distributed alongside threats. In this problem, agents obtain information at a location, but may suffer attacks from the threat at that location. In a decentralized fashion, each agent patrols in a designated area of the environment and interacts with a limited number of agents. Therefore, the goal of these agents is to coordinate to gather as much information as possible while limiting the damage incurred. Hence, we model this class of problem as a transition-decoupled partially observable Markov decision process with health constraints. Furthermore, we propose scalable decentralized online algorithms based on Monte Carlo tree search and a factored belief vector. We empirically evaluate our algorithms on decentralized patrolling problems and benchmark them against the state-of-the-art online planning solver. The results show that our approach outperforms the state-of-the-art by more than 56% for six agents patrolling problems and can scale up to 24 agents in reasonable time.

Modular synchronization in complex networks.

PubMed

Oh, E; Rho, K; Hong, H; Kahng, B

2005-10-01

We study the synchronization transition (ST) of a modified Kuramoto model on two different types of modular complex networks. It is found that the ST depends on the type of intermodular connections. For the network with decentralized (centralized) intermodular connections, the ST occurs at finite coupling constant (behaves abnormally). Such distinct features are found in the yeast protein interaction network and the Internet, respectively. Moreover, by applying the finite-size scaling analysis to an artificial network with decentralized intermodular connections, we obtain the exponent associated with the order parameter of the ST to be beta approximately 1 different from beta(MF) approximately 1/2 obtained from the scale-free network with the same degree distribution but the absence of modular structure, corresponding to the mean field value.

Intelligent Decentralized Control In Large Distributed Computer Systems

DTIC Science & Technology

1988-04-01

decentralized. The goal is to find a way for the agents to coordinate their actions to maximize some index of system performance. (Our main...shown in Figure 4.13. The controller observes the environ- ment through sensors, and then may issue a command (i.e., take action ) to affect the...the Hypothesis Generator and the Belief Manager, and finally actions are issued by the Action Generator, the Experiment Generator, or the Reflex

Symmetric Link Key Management for Secure Neighbor Discovery in a Decentralized Wireless Sensor Network

DTIC Science & Technology

2017-09-01

and to the Office of Management and Budget, Paperwork Reduction Project (0704-0188) Washington, DC 20503. 1. AGENCY USE ONLY (Leave blank) 2. REPORT...KEY MANAGEMENT FOR SECURE NEIGHBOR DISCOVERY IN A DECENTRALIZED WIRELESS SENSOR NETWORK by Kelvin T. Chew September 2017 Thesis Advisor...DATE September 2017 3. REPORT TYPE AND DATES COVERED Master’s thesis 4. TITLE AND SUBTITLE SYMMETRIC LINK KEY MANAGEMENT FOR SECURE NEIGHBOR

On Event-Triggered Adaptive Architectures for Decentralized and Distributed Control of Large-Scale Modular Systems

PubMed Central

Albattat, Ali; Gruenwald, Benjamin C.; Yucelen, Tansel

2016-01-01

The last decade has witnessed an increased interest in physical systems controlled over wireless networks (networked control systems). These systems allow the computation of control signals via processors that are not attached to the physical systems, and the feedback loops are closed over wireless networks. The contribution of this paper is to design and analyze event-triggered decentralized and distributed adaptive control architectures for uncertain networked large-scale modular systems; that is, systems consist of physically-interconnected modules controlled over wireless networks. Specifically, the proposed adaptive architectures guarantee overall system stability while reducing wireless network utilization and achieving a given system performance in the presence of system uncertainties that can result from modeling and degraded modes of operation of the modules and their interconnections between each other. In addition to the theoretical findings including rigorous system stability and the boundedness analysis of the closed-loop dynamical system, as well as the characterization of the effect of user-defined event-triggering thresholds and the design parameters of the proposed adaptive architectures on the overall system performance, an illustrative numerical example is further provided to demonstrate the efficacy of the proposed decentralized and distributed control approaches. PMID:27537894

On Event-Triggered Adaptive Architectures for Decentralized and Distributed Control of Large-Scale Modular Systems.

PubMed

Albattat, Ali; Gruenwald, Benjamin C; Yucelen, Tansel

2016-08-16

The last decade has witnessed an increased interest in physical systems controlled over wireless networks (networked control systems). These systems allow the computation of control signals via processors that are not attached to the physical systems, and the feedback loops are closed over wireless networks. The contribution of this paper is to design and analyze event-triggered decentralized and distributed adaptive control architectures for uncertain networked large-scale modular systems; that is, systems consist of physically-interconnected modules controlled over wireless networks. Specifically, the proposed adaptive architectures guarantee overall system stability while reducing wireless network utilization and achieving a given system performance in the presence of system uncertainties that can result from modeling and degraded modes of operation of the modules and their interconnections between each other. In addition to the theoretical findings including rigorous system stability and the boundedness analysis of the closed-loop dynamical system, as well as the characterization of the effect of user-defined event-triggering thresholds and the design parameters of the proposed adaptive architectures on the overall system performance, an illustrative numerical example is further provided to demonstrate the efficacy of the proposed decentralized and distributed control approaches.

Decentralized Multisensory Information Integration in Neural Systems.

PubMed

Zhang, Wen-Hao; Chen, Aihua; Rasch, Malte J; Wu, Si

2016-01-13

How multiple sensory cues are integrated in neural circuitry remains a challenge. The common hypothesis is that information integration might be accomplished in a dedicated multisensory integration area receiving feedforward inputs from the modalities. However, recent experimental evidence suggests that it is not a single multisensory brain area, but rather many multisensory brain areas that are simultaneously involved in the integration of information. Why many mutually connected areas should be needed for information integration is puzzling. Here, we investigated theoretically how information integration could be achieved in a distributed fashion within a network of interconnected multisensory areas. Using biologically realistic neural network models, we developed a decentralized information integration system that comprises multiple interconnected integration areas. Studying an example of combining visual and vestibular cues to infer heading direction, we show that such a decentralized system is in good agreement with anatomical evidence and experimental observations. In particular, we show that this decentralized system can integrate information optimally. The decentralized system predicts that optimally integrated information should emerge locally from the dynamics of the communication between brain areas and sheds new light on the interpretation of the connectivity between multisensory brain areas. To extract information reliably from ambiguous environments, the brain integrates multiple sensory cues, which provide different aspects of information about the same entity of interest. Here, we propose a decentralized architecture for multisensory integration. In such a system, no processor is in the center of the network topology and information integration is achieved in a distributed manner through reciprocally connected local processors. Through studying the inference of heading direction with visual and vestibular cues, we show that the decentralized system can integrate information optimally, with the reciprocal connections between processers determining the extent of cue integration. Our model reproduces known multisensory integration behaviors observed in experiments and sheds new light on our understanding of how information is integrated in the brain. Copyright © 2016 Zhang et al.

Decentralized Multisensory Information Integration in Neural Systems

PubMed Central

Zhang, Wen-hao; Chen, Aihua

2016-01-01

How multiple sensory cues are integrated in neural circuitry remains a challenge. The common hypothesis is that information integration might be accomplished in a dedicated multisensory integration area receiving feedforward inputs from the modalities. However, recent experimental evidence suggests that it is not a single multisensory brain area, but rather many multisensory brain areas that are simultaneously involved in the integration of information. Why many mutually connected areas should be needed for information integration is puzzling. Here, we investigated theoretically how information integration could be achieved in a distributed fashion within a network of interconnected multisensory areas. Using biologically realistic neural network models, we developed a decentralized information integration system that comprises multiple interconnected integration areas. Studying an example of combining visual and vestibular cues to infer heading direction, we show that such a decentralized system is in good agreement with anatomical evidence and experimental observations. In particular, we show that this decentralized system can integrate information optimally. The decentralized system predicts that optimally integrated information should emerge locally from the dynamics of the communication between brain areas and sheds new light on the interpretation of the connectivity between multisensory brain areas. SIGNIFICANCE STATEMENT To extract information reliably from ambiguous environments, the brain integrates multiple sensory cues, which provide different aspects of information about the same entity of interest. Here, we propose a decentralized architecture for multisensory integration. In such a system, no processor is in the center of the network topology and information integration is achieved in a distributed manner through reciprocally connected local processors. Through studying the inference of heading direction with visual and vestibular cues, we show that the decentralized system can integrate information optimally, with the reciprocal connections between processers determining the extent of cue integration. Our model reproduces known multisensory integration behaviors observed in experiments and sheds new light on our understanding of how information is integrated in the brain. PMID:26758843

Healthcare financing, decentralization and regional health planning: federal transfers and the healthcare networks in Minas Gerais, Brazil.

PubMed

Moreira, Laura Monteiro de Castro; Ferré, Felipe; Andrade, Eli Iola Gurgel

2017-04-01

The Decrees 4279/10 and 7508/11 established norms to guide health politics, with impacts on funding of the Middle and High Complexity Hospital and Outpatient. To verify the effects on the consolidation of care networks in Minas Gerais, we performed an analytical-descriptive study of the National Health Fund from 2006 to 2014. We observed decentralization of responsibilities, accompanied of resources and innovative financing mechanisms, resulting expansion of the network care model. The federal government definitions suggest reduction of the autonomy and limitation of regional solutions.

Neural joint control for Space Shuttle Remote Manipulator System

NASA Technical Reports Server (NTRS)

Atkins, Mark A.; Cox, Chadwick J.; Lothers, Michael D.; Pap, Robert M.; Thomas, Charles R.

1992-01-01

Neural networks are being used to control a robot arm in a telerobotic operation. The concept uses neural networks for both joint and inverse kinematics in a robotic control application. An upper level neural network is trained to learn inverse kinematic mappings. The output, a trajectory, is then fed to the Decentralized Adaptive Joint Controllers. This neural network implementation has shown that the controlled arm recovers from unexpected payload changes while following the reference trajectory. The neural network-based decentralized joint controller is faster, more robust and efficient than conventional approaches. Implementations of this architecture are discussed that would relax assumptions about dynamics, obstacles, and heavy loads. This system is being developed to use with the Space Shuttle Remote Manipulator System.

Decentralized Feedback Controllers for Robust Stabilization of Periodic Orbits of Hybrid Systems: Application to Bipedal Walking.

PubMed

Hamed, Kaveh Akbari; Gregg, Robert D

2017-07-01

This paper presents a systematic algorithm to design time-invariant decentralized feedback controllers to exponentially and robustly stabilize periodic orbits for hybrid dynamical systems against possible uncertainties in discrete-time phases. The algorithm assumes a family of parameterized and decentralized nonlinear controllers to coordinate interconnected hybrid subsystems based on a common phasing variable. The exponential and [Formula: see text] robust stabilization problems of periodic orbits are translated into an iterative sequence of optimization problems involving bilinear and linear matrix inequalities. By investigating the properties of the Poincaré map, some sufficient conditions for the convergence of the iterative algorithm are presented. The power of the algorithm is finally demonstrated through designing a set of robust stabilizing local nonlinear controllers for walking of an underactuated 3D autonomous bipedal robot with 9 degrees of freedom, impact model uncertainties, and a decentralization scheme motivated by amputee locomotion with a transpelvic prosthetic leg.

Decentralized Feedback Controllers for Robust Stabilization of Periodic Orbits of Hybrid Systems: Application to Bipedal Walking

PubMed Central

Hamed, Kaveh Akbari; Gregg, Robert D.

2016-01-01

This paper presents a systematic algorithm to design time-invariant decentralized feedback controllers to exponentially and robustly stabilize periodic orbits for hybrid dynamical systems against possible uncertainties in discrete-time phases. The algorithm assumes a family of parameterized and decentralized nonlinear controllers to coordinate interconnected hybrid subsystems based on a common phasing variable. The exponential and H2 robust stabilization problems of periodic orbits are translated into an iterative sequence of optimization problems involving bilinear and linear matrix inequalities. By investigating the properties of the Poincaré map, some sufficient conditions for the convergence of the iterative algorithm are presented. The power of the algorithm is finally demonstrated through designing a set of robust stabilizing local nonlinear controllers for walking of an underactuated 3D autonomous bipedal robot with 9 degrees of freedom, impact model uncertainties, and a decentralization scheme motivated by amputee locomotion with a transpelvic prosthetic leg. PMID:28959117

Representation of potential information gain to measure the price of anarchy on ISR activities

NASA Astrophysics Data System (ADS)

Ortiz-Peña, Hector J.; Hirsch, Michael; Karwan, Mark; Nagi, Rakesh; Sudit, Moises

2013-05-01

One of the main technical challenges facing intelligence analysts today is effectively determining information gaps from huge amounts of collected data. Moreover, getting the right information to/from the right person (e.g., analyst, warfighter on the edge) at the right time in a distributed environment has been elusive to our military forces. Synchronization of Intelligence, Surveillance, and Reconnaissance (ISR) activities to maximize the efficient utilization of limited resources (both in quantity and capabilities) has become critically important to increase the accuracy and timeliness of overall information gain. Given this reality, we are interested in quantifying the degradation of solution quality (i.e., information gain) as a centralized system synchronizing ISR activities (from information gap identification to information collection and dissemination) moves to a more decentralized framework. This evaluation extends the concept of price of anarchy, a measure of the inefficiency of a system when agents maximize decisions without coordination, by considering different levels of decentralization. Our initial research representing the potential information gain in geospatial and time discretized spaces is presented. This potential information gain map can represent a consolidation of Intelligence Preparation of the Battlefield products as input to automated ISR synchronization tools. Using the coordination of unmanned vehicles (UxVs) as an example, we developed a mathematical programming model for multi-perspective optimization in which each UxV develops its own fight plan to support mission objectives based only on its perspective of the environment (i.e., potential information gain map). Information is only exchanged when UxVs are part of the same communication network.

Decentralized Dimensionality Reduction for Distributed Tensor Data Across Sensor Networks.

PubMed

Liang, Junli; Yu, Guoyang; Chen, Badong; Zhao, Minghua

2016-11-01

This paper develops a novel decentralized dimensionality reduction algorithm for the distributed tensor data across sensor networks. The main contributions of this paper are as follows. First, conventional centralized methods, which utilize entire data to simultaneously determine all the vectors of the projection matrix along each tensor mode, are not suitable for the network environment. Here, we relax the simultaneous processing manner into the one-vector-by-one-vector (OVBOV) manner, i.e., determining the projection vectors (PVs) related to each tensor mode one by one. Second, we prove that in the OVBOV manner each PV can be determined without modifying any tensor data, which simplifies corresponding computations. Third, we cast the decentralized PV determination problem as a set of subproblems with consensus constraints, so that it can be solved in the network environment only by local computations and information communications among neighboring nodes. Fourth, we introduce the null space and transform the PV determination problem with complex orthogonality constraints into an equivalent hidden convex one without any orthogonality constraint, which can be solved by the Lagrange multiplier method. Finally, experimental results are given to show that the proposed algorithm is an effective dimensionality reduction scheme for the distributed tensor data across the sensor networks.

Real-Time Decentralized Neural Control via Backstepping for a Robotic Arm Powered by Industrial Servomotors.

PubMed

Vazquez, Luis A; Jurado, Francisco; Castaneda, Carlos E; Santibanez, Victor

2018-02-01

This paper presents a continuous-time decentralized neural control scheme for trajectory tracking of a two degrees of freedom direct drive vertical robotic arm. A decentralized recurrent high-order neural network (RHONN) structure is proposed to identify online, in a series-parallel configuration and using the filtered error learning law, the dynamics of the plant. Based on the RHONN subsystems, a local neural controller is derived via backstepping approach. The effectiveness of the decentralized neural controller is validated on a robotic arm platform, of our own design and unknown parameters, which uses industrial servomotors to drive the joints.

Decentralized safety concept for closed-loop controlled intensive care.

PubMed

Kühn, Jan; Brendle, Christian; Stollenwerk, André; Schweigler, Martin; Kowalewski, Stefan; Janisch, Thorsten; Rossaint, Rolf; Leonhardt, Steffen; Walter, Marian; Kopp, Rüdger

2017-04-01

This paper presents a decentralized safety concept for networked intensive care setups, for which a decentralized network of sensors and actuators is realized by embedded microcontroller nodes. It is evaluated for up to eleven medical devices in a setup for automated acute respiratory distress syndrome (ARDS) therapy. In this contribution we highlight a blood pump supervision as exemplary safety measure, which allows a reliable bubble detection in an extracorporeal blood circulation. The approach is validated with data of animal experiments including 35 bubbles with a size between 0.05 and 0.3 ml. All 18 bubbles with a size down to 0.15 ml are successfully detected. By using hidden Markov models (HMMs) as statistical method the number of necessary sensors can be reduced by two pressure sensors.

Neural-Network-Based Adaptive Decentralized Fault-Tolerant Control for a Class of Interconnected Nonlinear Systems.

PubMed

Li, Xiao-Jian; Yang, Guang-Hong

2018-01-01

This paper is concerned with the adaptive decentralized fault-tolerant tracking control problem for a class of uncertain interconnected nonlinear systems with unknown strong interconnections. An algebraic graph theory result is introduced to address the considered interconnections. In addition, to achieve the desirable tracking performance, a neural-network-based robust adaptive decentralized fault-tolerant control (FTC) scheme is given to compensate the actuator faults and system uncertainties. Furthermore, via the Lyapunov analysis method, it is proven that all the signals of the resulting closed-loop system are semiglobally bounded, and the tracking errors of each subsystem exponentially converge to a compact set, whose radius is adjustable by choosing different controller design parameters. Finally, the effectiveness and advantages of the proposed FTC approach are illustrated with two simulated examples.

Building a System of Autonomous Institutions: Coordination and Collaboration in British Columbia's Community College, University College, and Institute System.

ERIC Educational Resources Information Center

Gaber, Devron A.

2003-01-01

Explores the historical development of British Columbia's community college, university college, and institute system with the focus on voluntary collaboration in relation to provincial coordination and on swings between centralization and decentralization. Study examines development in BC's post secondary system in light of broader global…

Decentralized System Identification Using Stochastic Subspace Identification for Wireless Sensor Networks

PubMed Central

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

2015-01-01

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

Decentralized event-triggered synchronization of uncertain Markovian jumping neutral-type neural networks with mixed delays.

PubMed

Senan, Sibel; Syed Ali, M; Vadivel, R; Arik, Sabri

2017-02-01

In this study, we present an approach for the decentralized event-triggered synchronization of Markovian jumping neutral-type neural networks with mixed delays. We present a method for designing decentralized event-triggered synchronization, which only utilizes locally available information, in order to determine the time instants for transmission from sensors to a central controller. By applying a novel Lyapunov-Krasovskii functional, as well as using the reciprocal convex combination method and some inequality techniques such as Jensen's inequality, we obtain several sufficient conditions in terms of a set of linear matrix inequalities (LMIs) under which the delayed neural networks are stochastically stable in terms of the error systems. Finally, we conclude that the drive systems synchronize stochastically with the response systems. We show that the proposed stability criteria can be verified easily using the numerically efficient Matlab LMI toolbox. The effectiveness and feasibility of the results obtained are verified by numerical examples. Copyright © 2016 Elsevier Ltd. All rights reserved.

Cluster Size Optimization in Sensor Networks with Decentralized Cluster-Based Protocols

PubMed Central

Amini, Navid; Vahdatpour, Alireza; Xu, Wenyao; Gerla, Mario; Sarrafzadeh, Majid

2011-01-01

Network lifetime and energy-efficiency are viewed as the dominating considerations in designing cluster-based communication protocols for wireless sensor networks. This paper analytically provides the optimal cluster size that minimizes the total energy expenditure in such networks, where all sensors communicate data through their elected cluster heads to the base station in a decentralized fashion. LEACH, LEACH-Coverage, and DBS comprise three cluster-based protocols investigated in this paper that do not require any centralized support from a certain node. The analytical outcomes are given in the form of closed-form expressions for various widely-used network configurations. Extensive simulations on different networks are used to confirm the expectations based on the analytical results. To obtain a thorough understanding of the results, cluster number variability problem is identified and inspected from the energy consumption point of view. PMID:22267882

Distributed Environment Control Using Wireless Sensor/Actuator Networks for Lighting Applications

PubMed Central

Nakamura, Masayuki; Sakurai, Atsushi; Nakamura, Jiro

2009-01-01

We propose a decentralized algorithm to calculate the control signals for lights in wireless sensor/actuator networks. This algorithm uses an appropriate step size in the iterative process used for quickly computing the control signals. We demonstrate the accuracy and efficiency of this approach compared with the penalty method by using Mote-based mesh sensor networks. The estimation error of the new approach is one-eighth as large as that of the penalty method with one-fifth of its computation time. In addition, we describe our sensor/actuator node for distributed lighting control based on the decentralized algorithm and demonstrate its practical efficacy. PMID:22291525

Development of a decentralized multi-axis synchronous control approach for real-time networks.

PubMed

Xu, Xiong; Gu, Guo-Ying; Xiong, Zhenhua; Sheng, Xinjun; Zhu, Xiangyang

2017-05-01

The message scheduling and the network-induced delays of real-time networks, together with the different inertias and disturbances in different axes, make the synchronous control of the real-time network-based systems quite challenging. To address this challenge, a decentralized multi-axis synchronous control approach is developed in this paper. Due to the limitations of message scheduling and network bandwidth, error of the position synchronization is firstly defined in the proposed control approach as a subset of preceding-axis pairs. Then, a motion message estimator is designed to reduce the effect of network delays. It is proven that position and synchronization errors asymptotically converge to zero in the proposed controller with the delay compensation. Finally, simulation and experimental results show that the developed control approach can achieve the good position synchronization performance for the multi-axis motion over the real-time network. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

Global POPIN Advisory Committee meeting considers broad range of information issues.

PubMed

1995-09-01

The Global Population Information Network (POPIN) Advisory Committee met in Bangkok in June 1995. The Bali Declaration on Population and Sustainable Development adopted in 1992, and the Program of Action of the International Conference on Population and Development in 1994 recognized the importance of information in achieving information, education, and communication (IEC) goals in the population field. The information revolution would help achieve the population goals of individual countries, as more regional information networks are being created. POPIN's primary objective is to increase the awareness, knowledge, and understanding of population-related issues. There has been discussion about merging the POPLINE and POPIN thesauri and translating the Population Multilingual Thesaurus in several more languages. At this meeting a set of recommendations were adopted about POPIN's future operations concerning the continued growth of the network as a decentralized organization; the continued functioning of the Global POPIN Coordinating Unit as the central coordinating node; that the specialized agencies of the United Nations should participate actively in POPIN activities; and that the networks in each region should share information. In the production and dissemination of information various media should be used, including print, CD-ROM, e-mail, and the Internet; documents should be created in electronic format with developed guidelines; meetings should held on topics in information technology to provide training opportunities and exchange experience; presentations at conferences and symposia should be available in electronic format and made available through the Internet via the POPIN Gopher/Web Server. Follow-up activities should include the diversification of funding, the avoidance of duplication, and the achievement of cost-effectiveness.

Scaling theory for information networks.

PubMed

Moses, Melanie E; Forrest, Stephanie; Davis, Alan L; Lodder, Mike A; Brown, James H

2008-12-06

Networks distribute energy, materials and information to the components of a variety of natural and human-engineered systems, including organisms, brains, the Internet and microprocessors. Distribution networks enable the integrated and coordinated functioning of these systems, and they also constrain their design. The similar hierarchical branching networks observed in organisms and microprocessors are striking, given that the structure of organisms has evolved via natural selection, while microprocessors are designed by engineers. Metabolic scaling theory (MST) shows that the rate at which networks deliver energy to an organism is proportional to its mass raised to the 3/4 power. We show that computational systems are also characterized by nonlinear network scaling and use MST principles to characterize how information networks scale, focusing on how MST predicts properties of clock distribution networks in microprocessors. The MST equations are modified to account for variation in the size and density of transistors and terminal wires in microprocessors. Based on the scaling of the clock distribution network, we predict a set of trade-offs and performance properties that scale with chip size and the number of transistors. However, there are systematic deviations between power requirements on microprocessors and predictions derived directly from MST. These deviations are addressed by augmenting the model to account for decentralized flow in some microprocessor networks (e.g. in logic networks). More generally, we hypothesize a set of constraints between the size, power and performance of networked information systems including transistors on chips, hosts on the Internet and neurons in the brain.

Distribution Free Approach for Coordination of a Supply Chain with Consumer Return

NASA Astrophysics Data System (ADS)

Hu, Jinsong; Xu, Yuanji

Consumer return is considered in a coordination of a supply chain consisting of one manufacturer and one retailer. A distribution free approach is employed to deal with a centralized decision model and a decentralized model which are constructed under the situation with only knowing the demand function's mean and variance, respectively. A markdown money contract is designed to coordinate the supply chain, and it is also proved that the contract can make the supply chain perfectly coordinated. Several numerical examples are given at the end of this paper.

Combatting Global Infectious Diseases: A Network Effect of Specimen Referral Systems.

PubMed

Fonjungo, Peter N; Alemnji, George A; Kebede, Yenew; Opio, Alex; Mwangi, Christina; Spira, Thomas J; Beard, R Suzanne; Nkengasong, John N

2017-02-13

The recent Ebola virus outbreak in West Africa clearly demonstrated the critical role of laboratory systems and networks in responding to epidemics. Because of the huge challenges in establishing functional laboratories at all tiers of health systems in developing countries, strengthening specimen referral networks is critical. In this review article, we propose a platform strategy for developing specimen referral networks based on 2 models: centralized and decentralized laboratory specimen referral networks. These models have been shown to be effective in patient management in programs in resource-limited settings. Both models lead to reduced turnaround time and retain flexibility for integrating different specimen types. In Haiti, decentralized specimen referral systems resulted in a 182% increase in patients enrolling in human immunodeficiency virus treatment programs within 6 months. In Uganda, cost savings of up to 62% were observed with a centralized model. A platform strategy will create a network effect that will benefit multiple disease programs.

Resource allocation planning with international components

NASA Technical Reports Server (NTRS)

Burke, Gene; Durham, Ralph; Leppla, Frank; Porter, David

1993-01-01

Dumas, Briggs, Reid and Smith (1989) describe the need for identifying mutually acceptable methodologies for developing standard agreements for the exchange of tracking time or facility use among international components. One possible starting point is the current process used at the Jet Propulsion Laboratory (JPL) in planning the use of tracking resources. While there is a significant promise of better resource utilization by international cooperative agreements, there is a serious challenge to provide convenient user participation given the separate project and network locations. Coordination among users and facility providers will require a more decentralized communication process and a wider variety of automated planning tools to help users find potential exchanges. This paper provides a framework in which international cooperation in the utilization of ground based space communication systems can be facilitated.

Online network organization of Barcelona en Comú, an emergent movement-party.

PubMed

Aragón, Pablo; Gallego, Helena; Laniado, David; Volkovich, Yana; Kaltenbrunner, Andreas

2017-01-01

The emerging grassroots party Barcelona en Comú won the 2015 Barcelona City Council election. This candidacy was devised by activists involved in the Spanish 15M movement to transform citizen outrage into political change. On the one hand, the 15M movement was based on a decentralized structure. On the other hand, political science literature postulates that parties develop oligarchical leadership structures. This tension motivates to examine whether Barcelona en Comú preserved a decentralized structure or adopted a conventional centralized organization. In this study we develop a computational methodology to characterize the online network organization of every party in the election campaign on Twitter. Results on the network of retweets reveal that, while traditional parties are organized in a single cluster, for Barcelona en Comú two well-defined groups co-exist: a centralized cluster led by the candidate and party accounts, and a decentralized cluster with the movement activists. Furthermore, results on the network of replies also shows a dual structure: a cluster around the candidate receiving the largest attention from other parties, and another with the movement activists exhibiting a higher predisposition to dialogue with other parties.

Decentralized Hypothesis Testing in Energy Harvesting Wireless Sensor Networks

NASA Astrophysics Data System (ADS)

Tarighati, Alla; Gross, James; Jalden, Joakim

2017-09-01

We consider the problem of decentralized hypothesis testing in a network of energy harvesting sensors, where sensors make noisy observations of a phenomenon and send quantized information about the phenomenon towards a fusion center. The fusion center makes a decision about the present hypothesis using the aggregate received data during a time interval. We explicitly consider a scenario under which the messages are sent through parallel access channels towards the fusion center. To avoid limited lifetime issues, we assume each sensor is capable of harvesting all the energy it needs for the communication from the environment. Each sensor has an energy buffer (battery) to save its harvested energy for use in other time intervals. Our key contribution is to formulate the problem of decentralized detection in a sensor network with energy harvesting devices. Our analysis is based on a queuing-theoretic model for the battery and we propose a sensor decision design method by considering long term energy management at the sensors. We show how the performance of the system changes for different battery capacities. We then numerically show how our findings can be used in the design of sensor networks with energy harvesting sensors.

Decentralized DC Microgrid Monitoring and Optimization via Primary Control Perturbations

NASA Astrophysics Data System (ADS)

Angjelichinoski, Marko; Scaglione, Anna; Popovski, Petar; Stefanovic, Cedomir

2018-06-01

We treat the emerging power systems with direct current (DC) MicroGrids, characterized with high penetration of power electronic converters. We rely on the power electronics to propose a decentralized solution for autonomous learning of and adaptation to the operating conditions of the DC Mirogrids; the goal is to eliminate the need to rely on an external communication system for such purpose. The solution works within the primary droop control loops and uses only local bus voltage measurements. Each controller is able to estimate (i) the generation capacities of power sources, (ii) the load demands, and (iii) the conductances of the distribution lines. To define a well-conditioned estimation problem, we employ decentralized strategy where the primary droop controllers temporarily switch between operating points in a coordinated manner, following amplitude-modulated training sequences. We study the use of the estimator in a decentralized solution of the Optimal Economic Dispatch problem. The evaluations confirm the usefulness of the proposed solution for autonomous MicroGrid operation.

Cooperative vehicles for robust traffic congestion reduction: An analysis based on algorithmic, environmental and agent behavioral factors

PubMed Central

Desai, Prajakta; Desai, Aniruddha

2017-01-01

Traffic congestion continues to be a persistent problem throughout the world. As vehicle-to-vehicle communication develops, there is an opportunity of using cooperation among close proximity vehicles to tackle the congestion problem. The intuition is that if vehicles could cooperate opportunistically when they come close enough to each other, they could, in effect, spread themselves out among alternative routes so that vehicles do not all jam up on the same roads. Our previous work proposed a decentralized multiagent based vehicular congestion management algorithm entitled Congestion Avoidance and Route Allocation using Virtual Agent Negotiation (CARAVAN), wherein the vehicles acting as intelligent agents perform cooperative route allocation using inter-vehicular communication. This paper focuses on evaluating the practical applicability of this approach by testing its robustness and performance (in terms of travel time reduction), across variations in: (a) environmental parameters such as road network topology and configuration; (b) algorithmic parameters such as vehicle agent preferences and route cost/preference multipliers; and (c) agent-related parameters such as equipped/non-equipped vehicles and compliant/non-compliant agents. Overall, the results demonstrate the adaptability and robustness of the decentralized cooperative vehicles approach to providing global travel time reduction using simple local coordination strategies. PMID:28792513

Cooperative vehicles for robust traffic congestion reduction: An analysis based on algorithmic, environmental and agent behavioral factors.

PubMed

Desai, Prajakta; Loke, Seng W; Desai, Aniruddha

2017-01-01

Traffic congestion continues to be a persistent problem throughout the world. As vehicle-to-vehicle communication develops, there is an opportunity of using cooperation among close proximity vehicles to tackle the congestion problem. The intuition is that if vehicles could cooperate opportunistically when they come close enough to each other, they could, in effect, spread themselves out among alternative routes so that vehicles do not all jam up on the same roads. Our previous work proposed a decentralized multiagent based vehicular congestion management algorithm entitled Congestion Avoidance and Route Allocation using Virtual Agent Negotiation (CARAVAN), wherein the vehicles acting as intelligent agents perform cooperative route allocation using inter-vehicular communication. This paper focuses on evaluating the practical applicability of this approach by testing its robustness and performance (in terms of travel time reduction), across variations in: (a) environmental parameters such as road network topology and configuration; (b) algorithmic parameters such as vehicle agent preferences and route cost/preference multipliers; and (c) agent-related parameters such as equipped/non-equipped vehicles and compliant/non-compliant agents. Overall, the results demonstrate the adaptability and robustness of the decentralized cooperative vehicles approach to providing global travel time reduction using simple local coordination strategies.

Game-Based Virtual Worlds as Decentralized Virtual Activity Systems

NASA Astrophysics Data System (ADS)

Scacchi, Walt

There is widespread interest in the development and use of decentralized systems and virtual world environments as possible new places for engaging in collaborative work activities. Similarly, there is widespread interest in stimulating new technological innovations that enable people to come together through social networking, file/media sharing, and networked multi-player computer game play. A decentralized virtual activity system (DVAS) is a networked computer supported work/play system whose elements and social activities can be both virtual and decentralized (Scacchi et al. 2008b). Massively multi-player online games (MMOGs) such as World of Warcraft and online virtual worlds such as Second Life are each popular examples of a DVAS. Furthermore, these systems are beginning to be used for research, deve-lopment, and education activities in different science, technology, and engineering domains (Bainbridge 2007, Bohannon et al. 2009; Rieber 2005; Scacchi and Adams 2007; Shaffer 2006), which are also of interest here. This chapter explores two case studies of DVASs developed at the University of California at Irvine that employ game-based virtual worlds to support collaborative work/play activities in different settings. The settings include those that model and simulate practical or imaginative physical worlds in different domains of science, technology, or engineering through alternative virtual worlds where players/workers engage in different kinds of quests or quest-like workflows (Jakobsson 2006).

Study of the Effectiveness of OCR for Decentralized Data Capture and Conversion. Final Report.

ERIC Educational Resources Information Center

Liston, David M.; And Others

The ERIC network conversion to an OCR (Optical Character Recognition) mode of data entry was studied to analyze the potential effectiveness of OCR data entry for future EPC/s (Editorial Processing Centers). Study results are also applicable to any other system involving decentralized bibliographic data capture and conversion functions. The report…

Decentralized state estimation for a large-scale spatially interconnected system.

PubMed

Liu, Huabo; Yu, Haisheng

2018-03-01

A decentralized state estimator is derived for the spatially interconnected systems composed of many subsystems with arbitrary connection relations. An optimization problem on the basis of linear matrix inequality (LMI) is constructed for the computations of improved subsystem parameter matrices. Several computationally effective approaches are derived which efficiently utilize the block-diagonal characteristic of system parameter matrices and the sparseness of subsystem connection matrix. Moreover, this decentralized state estimator is proved to converge to a stable system and obtain a bounded covariance matrix of estimation errors under certain conditions. Numerical simulations show that the obtained decentralized state estimator is attractive in the synthesis of a large-scale networked system. Copyright © 2018 ISA. Published by Elsevier Ltd. All rights reserved.

Decentralized Bayesian search using approximate dynamic programming methods.

PubMed

Zhao, Yijia; Patek, Stephen D; Beling, Peter A

2008-08-01

We consider decentralized Bayesian search problems that involve a team of multiple autonomous agents searching for targets on a network of search points operating under the following constraints: 1) interagent communication is limited; 2) the agents do not have the opportunity to agree in advance on how to resolve equivalent but incompatible strategies; and 3) each agent lacks the ability to control or predict with certainty the actions of the other agents. We formulate the multiagent search-path-planning problem as a decentralized optimal control problem and introduce approximate dynamic heuristics that can be implemented in a decentralized fashion. After establishing some analytical properties of the heuristics, we present computational results for a search problem involving two agents on a 5 x 5 grid.

40 CFR 51.353 - Network type and program evaluation.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 2 2011-07-01 2011-07-01 false Network type and program evaluation. 51... Requirements § 51.353 Network type and program evaluation. Basic and enhanced I/M programs can be centralized.... (a) Presumptive equivalency. A decentralized network consisting of stations that only perform...

Using ontologies to model human navigation behavior in information networks: A study based on Wikipedia.

PubMed

Lamprecht, Daniel; Strohmaier, Markus; Helic, Denis; Nyulas, Csongor; Tudorache, Tania; Noy, Natalya F; Musen, Mark A

The need to examine the behavior of different user groups is a fundamental requirement when building information systems. In this paper, we present Ontology-based Decentralized Search (OBDS), a novel method to model the navigation behavior of users equipped with different types of background knowledge. Ontology-based Decentralized Search combines decentralized search, an established method for navigation in social networks, and ontologies to model navigation behavior in information networks. The method uses ontologies as an explicit representation of background knowledge to inform the navigation process and guide it towards navigation targets. By using different ontologies, users equipped with different types of background knowledge can be represented. We demonstrate our method using four biomedical ontologies and their associated Wikipedia articles. We compare our simulation results with base line approaches and with results obtained from a user study. We find that our method produces click paths that have properties similar to those originating from human navigators. The results suggest that our method can be used to model human navigation behavior in systems that are based on information networks, such as Wikipedia. This paper makes the following contributions: (i) To the best of our knowledge, this is the first work to demonstrate the utility of ontologies in modeling human navigation and (ii) it yields new insights and understanding about the mechanisms of human navigation in information networks.

Using ontologies to model human navigation behavior in information networks: A study based on Wikipedia

PubMed Central

Lamprecht, Daniel; Strohmaier, Markus; Helic, Denis; Nyulas, Csongor; Tudorache, Tania; Noy, Natalya F.; Musen, Mark A.

2015-01-01

The need to examine the behavior of different user groups is a fundamental requirement when building information systems. In this paper, we present Ontology-based Decentralized Search (OBDS), a novel method to model the navigation behavior of users equipped with different types of background knowledge. Ontology-based Decentralized Search combines decentralized search, an established method for navigation in social networks, and ontologies to model navigation behavior in information networks. The method uses ontologies as an explicit representation of background knowledge to inform the navigation process and guide it towards navigation targets. By using different ontologies, users equipped with different types of background knowledge can be represented. We demonstrate our method using four biomedical ontologies and their associated Wikipedia articles. We compare our simulation results with base line approaches and with results obtained from a user study. We find that our method produces click paths that have properties similar to those originating from human navigators. The results suggest that our method can be used to model human navigation behavior in systems that are based on information networks, such as Wikipedia. This paper makes the following contributions: (i) To the best of our knowledge, this is the first work to demonstrate the utility of ontologies in modeling human navigation and (ii) it yields new insights and understanding about the mechanisms of human navigation in information networks. PMID:26568745

Decentralized supply chain network design: monopoly, duopoly and oligopoly competitions under uncertainty

NASA Astrophysics Data System (ADS)

Seyedhosseini, Seyed Mohammad; Fahimi, Kaveh; Makui, Ahmad

2017-12-01

This paper presents the competitive supply chain network design problem in which n decentralized supply chains simultaneously enter the market with no existing rival chain, shape their networks and set wholesale and retail prices in competitive mode. The customer demand is elastic and price dependent, customer utility function is based on the Hoteling model and the chains produce identical or highly substitutable products. We construct a solution algorithm based on bi-level programming and possibility theory. In the proposed bi-level model, the inner part sets the prices based on simultaneous extra- and Stackleberg intra- chains competitions, and the outer part shapes the networks in cooperative competitions. Finally, we use a real-word study to discuss the effect of the different structures of the competitors on the equilibrium solution. Moreover, sensitivity analyses are conducted and managerial insights are offered.

Interdependent Network Recovery Games.

PubMed

Smith, Andrew M; González, Andrés D; Dueñas-Osorio, Leonardo; D'Souza, Raissa M

2017-10-30

Recovery of interdependent infrastructure networks in the presence of catastrophic failure is crucial to the economy and welfare of society. Recently, centralized methods have been developed to address optimal resource allocation in postdisaster recovery scenarios of interdependent infrastructure systems that minimize total cost. In real-world systems, however, multiple independent, possibly noncooperative, utility network controllers are responsible for making recovery decisions, resulting in suboptimal decentralized processes. With the goal of minimizing recovery cost, a best-case decentralized model allows controllers to develop a full recovery plan and negotiate until all parties are satisfied (an equilibrium is reached). Such a model is computationally intensive for planning and negotiating, and time is a crucial resource in postdisaster recovery scenarios. Furthermore, in this work, we prove this best-case decentralized negotiation process could continue indefinitely under certain conditions. Accounting for network controllers' urgency in repairing their system, we propose an ad hoc sequential game-theoretic model of interdependent infrastructure network recovery represented as a discrete time noncooperative game between network controllers that is guaranteed to converge to an equilibrium. We further reduce the computation time needed to find a solution by applying a best-response heuristic and prove bounds on ε-Nash equilibrium, where ε depends on problem inputs. We compare best-case and ad hoc models on an empirical interdependent infrastructure network in the presence of simulated earthquakes to demonstrate the extent of the tradeoff between optimality and computational efficiency. Our method provides a foundation for modeling sociotechnical systems in a way that mirrors restoration processes in practice. © 2017 Society for Risk Analysis.

Impacts of a Large Decentralized Telepathology Network in Canada.

PubMed

Pare, Guy; Meyer, Julien; Trudel, Marie-Claude; Tetu, Bernard

2016-03-01

Telepathology is a fast growing segment of the telemedicine field. As of yet, no prior research has investigated the impacts of large decentralized telepathology projects on patients, clinicians, and healthcare systems. This study aims to fill this gap. We report a benefits evaluation study of a large decentralized telepathology project deployed in Eastern Quebec, Canada whose main objective is to provide continuous coverage of intraoperative consultations in remote hospitals without pathologists on-site. The project involves 18 hospitals, making it one of the largest telepathology networks in the world. We conducted 43 semistructured interviews with several telepathology users and hospital managers. Archival data on the impacts of the telepathology project (e.g., number of service disruptions, average time between initial diagnosis and surgery) were also extracted and analyzed. Our findings show that no service disruptions were recorded in hospitals without pathologists following the deployment of telepathology. Surgeons noted that the use of intraoperative consultations enabled by telepathology helped avoid second surgeries and improved accessibility to care services. Telepathology was also perceived by our respondents as having positive impacts on the remote hospitals' ability to retain and recruit surgeons. The observed benefits should not leave the impression that implementing telepathology is a trivial matter. Indeed, many technical, human, and organizational challenges may be encountered. Telepathology can be highly useful in regional hospitals that do not have a pathologist on-site. More research is needed to investigate the challenges and benefits associated with large decentralized telepathology networks.

Sensor fusion IV: Control paradigms and data structures; Proceedings of the Meeting, Boston, MA, Nov. 12-15, 1991

NASA Technical Reports Server (NTRS)

Schenker, Paul S. (Editor)

1992-01-01

Various papers on control paradigms and data structures in sensor fusion are presented. The general topics addressed include: decision models and computational methods, sensor modeling and data representation, active sensing strategies, geometric planning and visualization, task-driven sensing, motion analysis, models motivated biology and psychology, decentralized detection and distributed decision, data fusion architectures, robust estimation of shapes and features, application and implementation. Some of the individual subjects considered are: the Firefly experiment on neural networks for distributed sensor data fusion, manifold traversing as a model for learning control of autonomous robots, choice of coordinate systems for multiple sensor fusion, continuous motion using task-directed stereo vision, interactive and cooperative sensing and control for advanced teleoperation, knowledge-based imaging for terrain analysis, physical and digital simulations for IVA robotics.

Robust Decentralized Nonlinear Control for a Twin Rotor MIMO System

PubMed Central

Belmonte, Lidia María; Morales, Rafael; Fernández-Caballero, Antonio; Somolinos, José Andrés

2016-01-01

This article presents the design of a novel decentralized nonlinear multivariate control scheme for an underactuated, nonlinear and multivariate laboratory helicopter denominated the twin rotor MIMO system (TRMS). The TRMS is characterized by a coupling effect between rotor dynamics and the body of the model, which is due to the action-reaction principle originated in the acceleration and deceleration of the motor-propeller groups. The proposed controller is composed of two nested loops that are utilized to achieve stabilization and precise trajectory tracking tasks for the controlled position of the generalized coordinates of the TRMS. The nonlinear internal loop is used to control the electrical dynamics of the platform, and the nonlinear external loop allows the platform to be perfectly stabilized and positioned in space. Finally, we illustrate the theoretical control developments with a set of experiments in order to verify the effectiveness of the proposed nonlinear decentralized feedback controller, in which a comparative study with other controllers is performed, illustrating the excellent performance of the proposed robust decentralized control scheme in both stabilization and trajectory tracking tasks. PMID:27472338

Robust Decentralized Nonlinear Control for a Twin Rotor MIMO System.

PubMed

Belmonte, Lidia María; Morales, Rafael; Fernández-Caballero, Antonio; Somolinos, José Andrés

2016-07-27

This article presents the design of a novel decentralized nonlinear multivariate control scheme for an underactuated, nonlinear and multivariate laboratory helicopter denominated the twin rotor MIMO system (TRMS). The TRMS is characterized by a coupling effect between rotor dynamics and the body of the model, which is due to the action-reaction principle originated in the acceleration and deceleration of the motor-propeller groups. The proposed controller is composed of two nested loops that are utilized to achieve stabilization and precise trajectory tracking tasks for the controlled position of the generalized coordinates of the TRMS. The nonlinear internal loop is used to control the electrical dynamics of the platform, and the nonlinear external loop allows the platform to be perfectly stabilized and positioned in space. Finally, we illustrate the theoretical control developments with a set of experiments in order to verify the effectiveness of the proposed nonlinear decentralized feedback controller, in which a comparative study with other controllers is performed, illustrating the excellent performance of the proposed robust decentralized control scheme in both stabilization and trajectory tracking tasks.

Decentralized Routing and Diameter Bounds in Entangled Quantum Networks

NASA Astrophysics Data System (ADS)

Gyongyosi, Laszlo; Imre, Sandor

2017-04-01

Entangled quantum networks are a necessity for any future quantum internet, long-distance quantum key distribution, and quantum repeater networks. The entangled quantum nodes can communicate through several different levels of entanglement, leading to a heterogeneous, multi-level entangled network structure. The level of entanglement between the quantum nodes determines the hop distance, the number of spanned nodes, and the probability of the existence of an entangled link in the network. In this work we define a decentralized routing for entangled quantum networks. We show that the probability distribution of the entangled links can be modeled by a specific distribution in a base-graph. The results allow us to perform efficient routing to find the shortest paths in entangled quantum networks by using only local knowledge of the quantum nodes. We give bounds on the maximum value of the total number of entangled links of a path. The proposed scheme can be directly applied in practical quantum communications and quantum networking scenarios. This work was partially supported by the Hungarian Scientific Research Fund - OTKA K-112125.

Refueling Strategies for a Team of Cooperating AUVs

DTIC Science & Technology

2011-01-01

manager, and thus the constraint a centrally managed underwater network imposes on the mission. Task management utilizing Robust Decentralized Task ...the computational complexity. A bid based approach to task management has also been studied as a possible means of decentralization of group task ...currently performing another task . In [18], ground robots perform distributed task allocation using the ASyMTRy-D algorithm, which is based on CNP

Stability of Fiber Optic Networked Decentralized Distributed Engine Control Under Time Delays

DTIC Science & Technology

2009-08-01

Nomenclature FADEC = Full Authority Digital Engine Control D2FADEC = Decentralized Distributed Full Authority Digital Engine Control DEC...Corporation (IFOS), bm@ifos.com. I American Institute of Aeronautics and Astronautics 2 II. Distributed Engine Control Systems FADEC Based on...of Full Authority Digital Engine Control ( FADEC ) are distributed at the component level. Each sensor/actuator is to be replaced by a smart sensor

Distributed architecture and distributed processing mode in urban sewage treatment

NASA Astrophysics Data System (ADS)

Zhou, Ruipeng; Yang, Yuanming

2017-05-01

Decentralized rural sewage treatment facility over the broad area, a larger operation and management difficult, based on the analysis of rural sewage treatment model based on the response to these challenges, we describe the principle, structure and function in networking technology and network communications technology as the core of distributed remote monitoring system, through the application of case analysis to explore remote monitoring system features in a decentralized rural sewage treatment facilities in the daily operation and management. Practice shows that the remote monitoring system to provide technical support for the long-term operation and effective supervision of the facilities, and reduced operating, maintenance and supervision costs for development.

Decentralized system identification using stochastic subspace identification on wireless smart sensor networks

NASA Astrophysics Data System (ADS)

Sim, Sung-Han; Spencer, Billie F., Jr.; Park, Jongwoong; Jung, Hyungjo

2012-04-01

Wireless Smart Sensor Networks (WSSNs) facilitates a new paradigm to structural identification and monitoring for civil infrastructure. Conventional monitoring systems based on wired sensors and centralized data acquisition and processing have been considered to be challenging and costly due to cabling and expensive equipment and maintenance costs. WSSNs have emerged as a technology that can overcome such difficulties, making deployment of a dense array of sensors on large civil structures both feasible and economical. However, as opposed to wired sensor networks in which centralized data acquisition and processing is common practice, WSSNs require decentralized computing algorithms to reduce data transmission due to the limitation associated with wireless communication. Thus, several system identification methods have been implemented to process sensor data and extract essential information, including Natural Excitation Technique with Eigensystem Realization Algorithm, Frequency Domain Decomposition (FDD), and Random Decrement Technique (RDT); however, Stochastic Subspace Identification (SSI) has not been fully utilized in WSSNs, while SSI has the strong potential to enhance the system identification. This study presents a decentralized system identification using SSI in WSSNs. The approach is implemented on MEMSIC's Imote2 sensor platform and experimentally verified using a 5-story shear building model.

DAISY-DAMP: A distributed AI system for the dynamic allocation and management of power

NASA Technical Reports Server (NTRS)

Hall, Steven B.; Ohler, Peter C.

1988-01-01

One of the critical parameters that must be addressed when designing a loosely coupled Distributed AI SYstem (DAISY) has to do with the degree to which authority is centralized or decentralized. The decision to implement the Dynamic Allocation and Management of Power (DAMP) system as a network of cooperating agents mandated this study. The DAISY-DAMP problem is described; the component agents of the system are characterized; and the communication protocols system elucidated. The motivations and advantages in designing the system with authority decentralized is discussed. Progress in the area of Speech Act theory is proposed as playing a role in constructing decentralized systems.

Introduction to Blueweb: A Decentralized Scatternet Formation Algorithm for Bluetooth Ad Hoc Networks

NASA Astrophysics Data System (ADS)

Yu, Chih-Min; Huang, Chia-Chi

In this letter, a decentralized scatternet formation algorithm called Bluelayer is proposed. First, Bluelayer uses a designated root to construct a tree-shaped subnet and propagates an integer variable k1 called counter limit as well as a constant k in its downstream direction to determine new roots. Then each new root asks its upstream master to start a return connection procedure to convert the tree-shaped subnet into a web-shaped subnet for its immediate upstream root. At the same time, each new root repeats the same procedure as the root to build its own subnet until the whole scatternet is formed. Simulation results show that Bluelayer achieves good network scalability and generates an efficient scatternet configuration for various sizes of Bluetooth ad hoc network.

Thoughts on the development of active regional public health systems.

PubMed

Reis, Ademar Arthur Chioro Dos; Sóter, Ana Paula Menezes; Furtado, Lumena Almeida Castro; Pereira, Silvana Souza da Silva

2017-04-01

Decentralization and regionalization are strategic themes for reforms in the health system. This paper analyzes the complex process of health regionalization being developed in Brazil. This paper identifies that the normative framework from the Brazilian National Health System, SUS has made advances with respect to its institutionalization and overcoming the initial centrality involved in municipalization. This has strengthened the development of regionalization and the intergovernmental agreement on health but the evidence points to the need to promote a revision. Based on document analysis, literature review and the views given by the authors involved in management in SUS as well as generating radically different views, the challenges for the construction of a regionalization that is active, is debated. We also discuss: its relations with planning and the dimensioning of service networks, the production of active care networks and shared management spaces, the inter-federative agreements and regional regulations, the capacity to coordinate regional systems and financing and the impact of the political dimension and electoral cycles. Regionalization (and SUS itself) is an open book, therefore ways and possibilities on how to maintain an active form of regionalization can be recommended.

Multi-agent coordination algorithms for control of distributed energy resources in smart grids

NASA Astrophysics Data System (ADS)

Cortes, Andres

Sustainable energy is a top-priority for researchers these days, since electricity and transportation are pillars of modern society. Integration of clean energy technologies such as wind, solar, and plug-in electric vehicles (PEVs), is a major engineering challenge in operation and management of power systems. This is due to the uncertain nature of renewable energy technologies and the large amount of extra load that PEVs would add to the power grid. Given the networked structure of a power system, multi-agent control and optimization strategies are natural approaches to address the various problems of interest for the safe and reliable operation of the power grid. The distributed computation in multi-agent algorithms addresses three problems at the same time: i) it allows for the handling of problems with millions of variables that a single processor cannot compute, ii) it allows certain independence and privacy to electricity customers by not requiring any usage information, and iii) it is robust to localized failures in the communication network, being able to solve problems by simply neglecting the failing section of the system. We propose various algorithms to coordinate storage, generation, and demand resources in a power grid using multi-agent computation and decentralized decision making. First, we introduce a hierarchical vehicle-one-grid (V1G) algorithm for coordination of PEVs under usage constraints, where energy only flows from the grid in to the batteries of PEVs. We then present a hierarchical vehicle-to-grid (V2G) algorithm for PEV coordination that takes into consideration line capacity constraints in the distribution grid, and where energy flows both ways, from the grid in to the batteries, and from the batteries to the grid. Next, we develop a greedy-like hierarchical algorithm for management of demand response events with on/off loads. Finally, we introduce distributed algorithms for the optimal control of distributed energy resources, i.e., generation and storage in a microgrid. The algorithms we present are provably correct and tested in simulation. Each algorithm is assumed to work on a particular network topology, and simulation studies are carried out in order to demonstrate their convergence properties to a desired solution.

Organizing a Learning Center.

ERIC Educational Resources Information Center

Davis, Harold S.

The organization and development of instructional materials centers (IMC's) as a part of a program of educational improvement is discussed. Analysis is made of the advantages, disadvantages, and organization of centralized IMC's, decentralized IMC's, and coordinated IMC's, with recommendations being made for their development. The operation of…

Trust: The Key to the Success of Mission Command in the Joint Force

DTIC Science & Technology

2015-05-18

Malaysia, Kuala Lumpur: International Conference on ISO9000. Schmidt, Todd A. “ Design , Mission Command and the Network: Enabling Organization...acknowledge that trust is one of the most important component of a decentralized command philosophy. Adding to this challenge is an increasingly...moving to mission command, we must acknowledge that trust is one of the most important components of a decentralized command philosophy. Adding to this

Formation Flying for Satellites and UAVs

NASA Technical Reports Server (NTRS)

Merrill, Garrick; Becker, Chris

2015-01-01

A formation monitoring and control system was developed utilizing mesh networking and decentralized control. Highlights of this system include low latency, seamless addition and removal of vehicles, network relay functionality, and the ability to run on a variety of hardware.

7 CFR 22.104 - General policy.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 7 Agriculture 1 2011-01-01 2011-01-01 false General policy. 22.104 Section 22.104 Agriculture Office of the Secretary of Agriculture RURAL DEVELOPMENT COORDINATION General § 22.104 General policy. Federal implementation of the Act will be consistent with the President's policy of decentralized...

7 CFR 22.104 - General policy.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 7 Agriculture 1 2013-01-01 2013-01-01 false General policy. 22.104 Section 22.104 Agriculture Office of the Secretary of Agriculture RURAL DEVELOPMENT COORDINATION General § 22.104 General policy. Federal implementation of the Act will be consistent with the President's policy of decentralized...

7 CFR 22.104 - General policy.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 7 Agriculture 1 2014-01-01 2014-01-01 false General policy. 22.104 Section 22.104 Agriculture Office of the Secretary of Agriculture RURAL DEVELOPMENT COORDINATION General § 22.104 General policy. Federal implementation of the Act will be consistent with the President's policy of decentralized...

7 CFR 22.104 - General policy.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 7 Agriculture 1 2012-01-01 2012-01-01 false General policy. 22.104 Section 22.104 Agriculture Office of the Secretary of Agriculture RURAL DEVELOPMENT COORDINATION General § 22.104 General policy. Federal implementation of the Act will be consistent with the President's policy of decentralized...

Two-echelon logistics service supply chain decision game considering quality supervision

NASA Astrophysics Data System (ADS)

Shi, Jiaying

2017-10-01

Due to the increasing importance of supply chain logistics service, we established the Stackelberg game model between single integrator and single subcontractors under decentralized and centralized circumstances, and found that logistics services integrators as a leader prefer centralized decision-making but logistics service subcontractors tend to the decentralized decision-making. Then, we further analyzed why subcontractor chose to deceive and rebuilt a principal-agent game model to monitor the logistics services quality of them. Mixed Strategy Nash equilibrium and related parameters were discussed. The results show that strengthening the supervision and coordination can improve the quality level of logistics service supply chain.

The impact of South Africa's new constitution on the organization of health services in the post-apartheid era.

PubMed

Pillay, Y

2001-08-01

This essay evaluates the transformation of the health care system in South Africa in the five years following the end of apartheid. This period has witnessed dramatic and wide-ranging changes in the roles of the central and provincial governments as well as many of the same problems related to decentralization as have been seen elsewhere in the world. The importance of effective intergovernmental relations to the creation of a national health system is highlighted. Negotiation. contracting, and coordination skills and mechanisms need to be strengthened to ensure a more effective national health system within a decentralized political system.

Energy management and multi-layer control of networked microgrids

NASA Astrophysics Data System (ADS)

Zamora, Ramon

Networked microgrids is a group of neighboring microgrids that has ability to interchange power when required in order to increase reliability and resiliency. Networked microgrid can operate in different possible configurations including: islanded microgrid, a grid-connected microgrid without a tie-line converter, a grid-connected microgrid with a tie-line converter, and networked microgrids. These possible configurations and specific characteristics of renewable energy offer challenges in designing control and management algorithms for voltage, frequency and power in all possible operating scenarios. In this work, control algorithm is designed based on large-signal model that enables microgrid to operate in wide range of operating points. A combination between PI controller and feed-forward measured system responses will compensate for the changes in operating points. The control architecture developed in this work has multi-layers and the outer layer is slower than the inner layer in time response. The main responsibility of the designed controls are to regulate voltage magnitude and frequency, as well as output power of the DG(s). These local controls also integrate with a microgrid level energy management system or microgrid central controller (MGCC) for power and energy balance for. the entire microgrid in islanded, grid-connected, or networked microgid mode. The MGCC is responsible to coordinate the lower level controls to have reliable and resilient operation. In case of communication network failure, the decentralized energy management will operate locally and will activate droop control. Simulation results indicate the superiority of designed control algorithms compared to existing ones.

Economics of Computing: The Case of Centralized Network File Servers.

ERIC Educational Resources Information Center

Solomon, Martin B.

1994-01-01

Discusses computer networking and the cost effectiveness of decentralization, including local area networks. A planned experiment with a centralized approach to the operation and management of file servers at the University of South Carolina is described that hopes to realize cost savings and the avoidance of staffing problems. (Contains four…

Network-Cognizant Design of Decentralized Volt/VAR Controllers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baker, Kyri A; Bernstein, Andrey; Zhao, Changhong

This paper considers the problem of designing decentralized Volt/VAR controllers for distributed energy resources (DERs). The voltage-reactive power characteristics of individual DERs are obtained by solving a convex optimization problem, where given performance objectives (e.g., minimization of the voltage deviations from a given profile) are specified and stability constraints are enforced. The resultant Volt/VAR characteristics are network-cognizant, in the sense that they embed information on the location of the DERs and, consequently, on the effect of reactive-power adjustments on the voltages throughout the feeder. Bounds on the maximum voltage deviation incurred by the controllers are analytically established. Numerical results aremore » reported to corroborate the technical findings.« less

Integration of Decentralized Thermal Storages Within District Heating (DH) Networks

NASA Astrophysics Data System (ADS)

Schuchardt, Georg K.

2016-12-01

Thermal Storages and Thermal Accumulators are an important component within District Heating (DH) systems, adding flexibility and offering additional business opportunities for these systems. Furthermore, these components have a major impact on the energy and exergy efficiency as well as the heat losses of the heat distribution system. Especially the integration of Thermal Storages within ill-conditioned parts of the overall DH system enhances the efficiency of the heat distribution. Regarding an illustrative and simplified example for a DH system, the interactions of different heat storage concepts (centralized and decentralized) and the heat losses, energy and exergy efficiencies will be examined by considering the thermal state of the heat distribution network.

GoDisco: Selective Gossip Based Dissemination of Information in Social Community Based Overlays

NASA Astrophysics Data System (ADS)

Datta, Anwitaman; Sharma, Rajesh

We propose and investigate a gossip based, social principles and behavior inspired decentralized mechanism (GoDisco) to disseminate information in online social community networks, using exclusively social links and exploiting semantic context to keep the dissemination process selective to relevant nodes. Such a designed dissemination scheme using gossiping over a egocentric social network is unique and is arguably a concept whose time has arrived, emulating word of mouth behavior and can have interesting applications like probabilistic publish/subscribe, decentralized recommendation and contextual advertisement systems, to name a few. Simulation based experiments show that despite using only local knowledge and contacts, the system has good global coverage and behavior.

Communication network for decentralized remote tele-science during the Spacelab mission IML-2

NASA Technical Reports Server (NTRS)

Christ, Uwe; Schulz, Klaus-Juergen; Incollingo, Marco

1994-01-01

The ESA communication network for decentralized remote telescience during the Spacelab mission IML-2, called Interconnection Ground Subnetwork (IGS), provided data, voice conferencing, video distribution/conferencing and high rate data services to 5 remote user centers in Europe. The combination of services allowed the experimenters to interact with their experiments as they would normally do from the Payload Operations Control Center (POCC) at MSFC. In addition, to enhance their science results, they were able to make use of reference facilities and computing resources in their home laboratory, which typically are not available in the POCC. Characteristics of the IML-2 communications implementation were the adaptation to the different user needs based on modular service capabilities of IGS and the cost optimization for the connectivity. This was achieved by using a combination of traditional leased lines, satellite based VSAT connectivity and N-ISDN according to the simulation and mission schedule for each remote site. The central management system of IGS allows minimization of staffing and the involvement of communications personnel at the remote sites. The successful operation of IGS for IML-2 as a precursor network for the Columbus Orbital Facility (COF) has proven the concept for communications to support the operation of the COF decentralized scenario.

An architecture for integrating distributed and cooperating knowledge-based Air Force decision aids

NASA Technical Reports Server (NTRS)

Nugent, Richard O.; Tucker, Richard W.

1988-01-01

MITRE has been developing a Knowledge-Based Battle Management Testbed for evaluating the viability of integrating independently-developed knowledge-based decision aids in the Air Force tactical domain. The primary goal for the testbed architecture is to permit a new system to be added to a testbed with little change to the system's software. Each system that connects to the testbed network declares that it can provide a number of services to other systems. When a system wants to use another system's service, it does not address the server system by name, but instead transmits a request to the testbed network asking for a particular service to be performed. A key component of the testbed architecture is a common database which uses a relational database management system (RDBMS). The RDBMS provides a database update notification service to requesting systems. Normally, each system is expected to monitor data relations of interest to it. Alternatively, a system may broadcast an announcement message to inform other systems that an event of potential interest has occurred. Current research is aimed at dealing with issues resulting from integration efforts, such as dealing with potential mismatches of each system's assumptions about the common database, decentralizing network control, and coordinating multiple agents.

A Coordinated Decentralized Approach to Online Project Development

ERIC Educational Resources Information Center

Mykota, David

2013-01-01

With the growth rate of online learning outpacing traditional face-to-face instruction, universities are beginning to recognize the importance of strategic planning in its development. Making the case for online learning requires sound project management practices and an understanding of the business models on which it is predicated. The objective…

Inside Public Television

ERIC Educational Resources Information Center

Wurtzel, Alan

1977-01-01

In the continuing saga of the perils of public television, the author, University of Georgia School of Journalism TV Coordinator, gives the viewer an inside look at the unwieldy structure of this non-commercial medium. Today's episode: Will high-quality programming survive? The players: 265 independent public TV stations, a decentralized public TV…

Distributed and decentralized state estimation in gas networks as distributed parameter systems.

PubMed

Ahmadian Behrooz, Hesam; Boozarjomehry, R Bozorgmehry

2015-09-01

In this paper, a framework for distributed and decentralized state estimation in high-pressure and long-distance gas transmission networks (GTNs) is proposed. The non-isothermal model of the plant including mass, momentum and energy balance equations are used to simulate the dynamic behavior. Due to several disadvantages of implementing a centralized Kalman filter for large-scale systems, the continuous/discrete form of extended Kalman filter for distributed and decentralized estimation (DDE) has been extended for these systems. Accordingly, the global model is decomposed into several subsystems, called local models. Some heuristic rules are suggested for system decomposition in gas pipeline networks. In the construction of local models, due to the existence of common states and interconnections among the subsystems, the assimilation and prediction steps of the Kalman filter are modified to take the overlapping and external states into account. However, dynamic Riccati equation for each subsystem is constructed based on the local model, which introduces a maximum error of 5% in the estimated standard deviation of the states in the benchmarks studied in this paper. The performance of the proposed methodology has been shown based on the comparison of its accuracy and computational demands against their counterparts in centralized Kalman filter for two viable benchmarks. In a real life network, it is shown that while the accuracy is not significantly decreased, the real-time factor of the state estimation is increased by a factor of 10. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

Social network analysis of child and adult interorganizational connections.

PubMed

Davis, Maryann; Koroloff, Nancy; Johnsen, Matthew

2012-01-01

Because most programs serve either children and their families or adults, a critical component of service and treatment continuity in mental health and related services for individuals transitioning into adulthood (ages 14-25) is coordination across programs on either side of the adult age divide. This study was conducted in Clark County, Washington, a community that had received a Partnership for Youth Transition grant from the Federal Center for Mental Health Services. Social Network Analysis methodology was used to describe the strength and direction of each organization's relationship to other organizations in the transition network. Interviews were conducted before grant implementation (n=103) and again four years later (n=99). The findings of the study revealed significant changes in the nature of relationships between organizations over time. While the overall density of the transition service network remained stable, specific ways of connecting did change. Some activities became more decentralized while others became more inclusive as evidenced by the increase in size of the largest K-core. This was particularly true for the activity of "receiving referrals." These changes reflected more direct contact between child and adult serving organizations. The two separate child and adult systems identified at baseline appeared more integrated by the end of the grant period. Having greater connectivity among all organizations regardless of ages served should benefit youth and young adults of transition age. This study provides further evidence that Social Network Analysis is a useful method for measuring change in service system integration over time.

Outdoor flocking of quadcopter drones with decentralized model predictive control.

PubMed

Yuan, Quan; Zhan, Jingyuan; Li, Xiang

2017-11-01

In this paper, we present a multi-drone system featured with a decentralized model predictive control (DMPC) flocking algorithm. The drones gather localized information from neighbors and update their velocities using the DMPC flocking algorithm. In the multi-drone system, data packages are transmitted through XBee ® wireless modules in broadcast mode, yielding such an anonymous and decentralized system where all the calculations and controls are completed on an onboard minicomputer of each drone. Each drone is a double-layered agent system with the coordination layer running multi-drone flocking algorithms and the flight control layer navigating the drone, and the final formation of the flock relies on both the communication range and the desired inter-drone distance. We give both numerical simulations and field tests with a flock of five drones, showing that the DMPC flocking algorithm performs well on the presented multi-drone system in both the convergence rate and the ability of tracking a desired path. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

DC Microgrids–Part I: A Review of Control Strategies and Stabilization Techniques

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dragicevic, Tomislav; Lu, Xiaonan; Vasquez, Juan

2015-01-01

This paper presents a review of control strategies, stability analysis, and stabilization techniques for dc microgrids (MGs). Overall control is systematically classified into local and coordinated control levels according to respective functionalities in each level. As opposed to local control, which relies only on local measurements, some line of communication between units needs to be made available in order to achieve the coordinated control. Depending on the communication method, three basic coordinated control strategies can be distinguished, i.e., decentralized, centralized, and distributed control. Decentralized control can be regarded as an extension of the local control since it is also basedmore » exclusively on local measurements. In contrast, centralized and distributed control strategies rely on digital communication technologies. A number of approaches using these three coordinated control strategies to achieve various control objectives are reviewed in this paper. Moreover, properties of dc MG dynamics and stability are discussed. This paper illustrates that tightly regulated point-of-load converters tend to reduce the stability margins of the system since they introduce negative impedances, which can potentially oscillate with lightly damped power supply input filters. It is also demonstrated that how the stability of the whole system is defined by the relationship of the source and load impedances, referred to as the minor loop gain. Several prominent specifications for the minor loop gain are reviewed. Finally, a number of active stabilization techniques are presented.« less

DQM: Decentralized Quadratically Approximated Alternating Direction Method of Multipliers

NASA Astrophysics Data System (ADS)

Mokhtari, Aryan; Shi, Wei; Ling, Qing; Ribeiro, Alejandro

2016-10-01

This paper considers decentralized consensus optimization problems where nodes of a network have access to different summands of a global objective function. Nodes cooperate to minimize the global objective by exchanging information with neighbors only. A decentralized version of the alternating directions method of multipliers (DADMM) is a common method for solving this category of problems. DADMM exhibits linear convergence rate to the optimal objective but its implementation requires solving a convex optimization problem at each iteration. This can be computationally costly and may result in large overall convergence times. The decentralized quadratically approximated ADMM algorithm (DQM), which minimizes a quadratic approximation of the objective function that DADMM minimizes at each iteration, is proposed here. The consequent reduction in computational time is shown to have minimal effect on convergence properties. Convergence still proceeds at a linear rate with a guaranteed constant that is asymptotically equivalent to the DADMM linear convergence rate constant. Numerical results demonstrate advantages of DQM relative to DADMM and other alternatives in a logistic regression problem.

The Internet and World-Wide-Web: Potential Benefits to Rural Schools.

ERIC Educational Resources Information Center

Barker, Bruce O.

The Internet is a decentralized collection of computer networks managed by separate groups using a common set of technical standards. The Internet has tremendous potential as an educational resource by providing access to networking through worldwide electronic mail, various databases, and electronic bulletin boards; collaborative investigation…

The Death of Distance and the Rise of the Network Society.

ERIC Educational Resources Information Center

Saba, Farhad

1999-01-01

Discusses the rise of computer networks, telecommuting possibilities, the growing global economy, and possible resulting trends in the population of cities. Implications for higher education are suggested, including the centralization of certain core operations and the decentralization of other services to address the varied needs of students.…

Library and Information Networks: Centralization and Decentralization.

ERIC Educational Resources Information Center

Segal, JoAnn S.

1988-01-01

Describes the development of centralized library networks and the current factors that make library sharing on a smaller scale feasible. The discussion covers the need to decide the level at which library cooperation should occur and the possibility of linking via the Open System Interface Reference Model. (37 references) (CLB)

Coordinating Decentralized Learning and Conflict Resolution across Agent Boundaries

ERIC Educational Resources Information Center

Cheng, Shanjun

2012-01-01

It is crucial for embedded systems to adapt to the dynamics of open environments. This adaptation process becomes especially challenging in the context of multiagent systems because of scalability, partial information accessibility and complex interaction of agents. It is a challenge for agents to learn good policies, when they need to plan and…

Extreme Makeover: IT Edition

ERIC Educational Resources Information Center

Schaffhauser, Dian

2011-01-01

Air-traffic controller might be a relaxing second career for anyone who's coordinated IT operations at a large research university. Just ask administrators at the University of Michigan in Ann Arbor. As at most big universities, IT operations on the academic side are decentralized on a major scale. When a faculty member in one of Michigan's 19…

A Hierarchical Auction-Based Mechanism for Real-Time Resource Allocation in Cloud Robotic Systems.

PubMed

Wang, Lujia; Liu, Ming; Meng, Max Q-H

2017-02-01

Cloud computing enables users to share computing resources on-demand. The cloud computing framework cannot be directly mapped to cloud robotic systems with ad hoc networks since cloud robotic systems have additional constraints such as limited bandwidth and dynamic structure. However, most multirobotic applications with cooperative control adopt this decentralized approach to avoid a single point of failure. Robots need to continuously update intensive data to execute tasks in a coordinated manner, which implies real-time requirements. Thus, a resource allocation strategy is required, especially in such resource-constrained environments. This paper proposes a hierarchical auction-based mechanism, namely link quality matrix (LQM) auction, which is suitable for ad hoc networks by introducing a link quality indicator. The proposed algorithm produces a fast and robust method that is accurate and scalable. It reduces both global communication and unnecessary repeated computation. The proposed method is designed for firm real-time resource retrieval for physical multirobot systems. A joint surveillance scenario empirically validates the proposed mechanism by assessing several practical metrics. The results show that the proposed LQM auction outperforms state-of-the-art algorithms for resource allocation.

IPTV multicast with peer-assisted lossy error control

NASA Astrophysics Data System (ADS)

Li, Zhi; Zhu, Xiaoqing; Begen, Ali C.; Girod, Bernd

2010-07-01

Emerging IPTV technology uses source-specific IP multicast to deliver television programs to end-users. To provide reliable IPTV services over the error-prone DSL access networks, a combination of multicast forward error correction (FEC) and unicast retransmissions is employed to mitigate the impulse noises in DSL links. In existing systems, the retransmission function is provided by the Retransmission Servers sitting at the edge of the core network. In this work, we propose an alternative distributed solution where the burden of packet loss repair is partially shifted to the peer IP set-top boxes. Through Peer-Assisted Repair (PAR) protocol, we demonstrate how the packet repairs can be delivered in a timely, reliable and decentralized manner using the combination of server-peer coordination and redundancy of repairs. We also show that this distributed protocol can be seamlessly integrated with an application-layer source-aware error protection mechanism called forward and retransmitted Systematic Lossy Error Protection (SLEP/SLEPr). Simulations show that this joint PARSLEP/ SLEPr framework not only effectively mitigates the bottleneck experienced by the Retransmission Servers, thus greatly enhancing the scalability of the system, but also efficiently improves the resistance to the impulse noise.

Empowering health personnel for decentralized health planning in India: The Public Health Resource Network.

PubMed

Kalita, Anuska; Zaidi, Sarover; Prasad, Vandana; Raman, V R

2009-07-20

The Public Health Resource Network is an innovative distance-learning course in training, motivating, empowering and building a network of health personnel from government and civil society groups. Its aim is to build human resource capacity for strengthening decentralized health planning, especially at the district level, to improve accountability of health systems, elicit community participation for health, ensure equitable and accessible health facilities and to bring about convergence in programmes and services. The question confronting health systems in India is how best to reform, revitalize and resource primary health systems to deliver different levels of service aligned to local realities, ensuring universal coverage, equitable access, efficiency and effectiveness, through an empowered cadre of health personnel. To achieve these outcomes it is essential that health planning be decentralized. Districts vary widely according to the specific needs of their population, and even more so in terms of existing interventions and available resources. Strategies, therefore, have to be district-specific, not only because health needs vary, but also because people's perceptions and capacities to intervene and implement programmes vary. In centrally designed plans there is little scope for such adaptation and contextualization, and hence decentralized planning becomes crucial. To undertake these initiatives, there is a strong need for trained, motivated, empowered and networked health personnel. It is precisely at this level that a lack of technical knowledge and skills and the absence of a supportive network or adequate educational opportunities impede personnel from making improvements. The absence of in-service training and of training curricula that reflect field realities also adds to this, discouraging health workers from pursuing effective strategies. The Public Health Resource Network is thus an attempt to reach out to motivated though often isolated health workers. It interacts with, and works to empower, health personnel within the government health system as well as civil society, to meaningfully participate in and strengthen decentralized planning processes and outcomes. Structured as an innovative distance-learning course spread over 12 to 18 months of coursework and contact programmes, the Public Health Resource Network comprises 14 core modules and five optional courses. The technical content and contact programmes have been specifically developed to build perspectives and technical knowledge of participants and provide them with a variety of options that can be immediately put into practice within their work environments and everyday roles. The thematic areas of the course modules range from technical knowledge related to maternal and child health and communicable and noncommunicable diseases; programmatic and systemic knowledge related to health planning, convergence, health management and public-private partnerships; to perspective-building knowledge related to mainstreaming gender issues and community participation. Currently the Public Health Resource Network has been launched in four states of India--Chhattisgarh, Jharkhand, Bihar and Orissa--in its first phase, and reaches out to more than 500 participants with diverse backgrounds. The initiative has received valuable support from central and state government departments of health, state training institutes, the National Rural Health Mission--the current comprehensive health policy in the country--and leading civil society organizations.

Empowering health personnel for decentralized health planning in India: The Public Health Resource Network

PubMed Central

Kalita, Anuska; Zaidi, Sarover; Prasad, Vandana; Raman, VR

2009-01-01

The Public Health Resource Network is an innovative distance-learning course in training, motivating, empowering and building a network of health personnel from government and civil society groups. Its aim is to build human resource capacity for strengthening decentralized health planning, especially at the district level, to improve accountability of health systems, elicit community participation for health, ensure equitable and accessible health facilities and to bring about convergence in programmes and services. The question confronting health systems in India is how best to reform, revitalize and resource primary health systems to deliver different levels of service aligned to local realities, ensuring universal coverage, equitable access, efficiency and effectiveness, through an empowered cadre of health personnel. To achieve these outcomes it is essential that health planning be decentralized. Districts vary widely according to the specific needs of their population, and even more so in terms of existing interventions and available resources. Strategies, therefore, have to be district-specific, not only because health needs vary, but also because people's perceptions and capacities to intervene and implement programmes vary. In centrally designed plans there is little scope for such adaptation and contextualization, and hence decentralized planning becomes crucial. To undertake these initiatives, there is a strong need for trained, motivated, empowered and networked health personnel. It is precisely at this level that a lack of technical knowledge and skills and the absence of a supportive network or adequate educational opportunities impede personnel from making improvements. The absence of in-service training and of training curricula that reflect field realities also adds to this, discouraging health workers from pursuing effective strategies. The Public Health Resource Network is thus an attempt to reach out to motivated though often isolated health workers. It interacts with, and works to empower, health personnel within the government health system as well as civil society, to meaningfully participate in and strengthen decentralized planning processes and outcomes. Structured as an innovative distance-learning course spread over 12 to 18 months of coursework and contact programmes, the Public Health Resource Network comprises 14 core modules and five optional courses. The technical content and contact programmes have been specifically developed to build perspectives and technical knowledge of participants and provide them with a variety of options that can be immediately put into practice within their work environments and everyday roles. The thematic areas of the course modules range from technical knowledge related to maternal and child health and communicable and noncommunicable diseases; programmatic and systemic knowledge related to health planning, convergence, health management and public-private partnerships; to perspective-building knowledge related to mainstreaming gender issues and community participation. Currently the Public Health Resource Network has been launched in four states of India – Chhattisgarh, Jharkhand, Bihar and Orissa – in its first phase, and reaches out to more than 500 participants with diverse backgrounds. The initiative has received valuable support from central and state government departments of health, state training institutes, the National Rural Health Mission – the current comprehensive health policy in the country – and leading civil society organizations. PMID:19615106

Social Mobilization and Community Engagement Central to the Ebola Response in West Africa: Lessons for Future Public Health Emergencies

PubMed Central

Gillespie, Amaya M; Obregon, Rafael; El Asawi, Rania; Richey, Catherine; Manoncourt, Erma; Joshi, Kshiitij; Naqvi, Savita; Pouye, Ade; Safi, Naqibullah; Chitnis, Ketan; Quereshi, Sabeeha

2016-01-01

ABSTRACT Following the World Health Organization (WHO) declaration of a Public Health Emergency of International Concern regarding the Ebola outbreak in West Africa in July 2014, UNICEF was asked to co-lead, in coordination with WHO and the ministries of health of affected countries, the communication and social mobilization component—which UNICEF refers to as communication for development (C4D)—of the Ebola response. For the first time in an emergency setting, C4D was formally incorporated into each country's national response, alongside more typical components such as supplies and logistics, surveillance, and clinical care. This article describes the lessons learned about social mobilization and community engagement in the emergency response to the Ebola outbreak, with a particular focus on UNICEF's C4D work in Guinea, Liberia, and Sierra Leone. The lessons emerged through an assessment conducted by UNICEF using 4 methods: a literature review of key documents, meeting reports, and other articles; structured discussions conducted in June 2015 and October 2015 with UNICEF and civil society experts; an electronic survey, launched in October and November 2015, with staff from government, the UN, or any partner organization who worked on Ebola (N = 53); and key informant interviews (N = 5). After triangulating the findings from all data sources, we distilled lessons under 7 major domains: (1) strategy and decentralization: develop a comprehensive C4D strategy with communities at the center and decentralized programming to facilitate flexibility and adaptation to the local context; (2) coordination: establish C4D leadership with the necessary authority to coordinate between partners and enforce use of standard operating procedures as a central coordination and quality assurance tool; (3) entering and engaging communities: invest in key communication channels (such as radio) and trusted local community members; (4) messaging: adapt messages and strategies continually as patterns of the epidemic change over time; (5) partnerships: invest in strategic partnerships with community, religious leaders, journalists, radio stations, and partner organizations; (6) capacity building: support a network of local and international professionals with capacity for C4D who can be deployed rapidly; (7) data and performance monitoring: establish clear C4D process and impact indicators and strive for real-time data analysis and rapid feedback to communities and authorities to inform decision making. Ultimately, communication, community engagement, and social mobilization need to be formally placed within the global humanitarian response architecture with proper funding to effectively support future public health emergencies, which are as much a social as a health phenomenon. PMID:28031301

Social Mobilization and Community Engagement Central to the Ebola Response in West Africa: Lessons for Future Public Health Emergencies.

PubMed

Gillespie, Amaya M; Obregon, Rafael; El Asawi, Rania; Richey, Catherine; Manoncourt, Erma; Joshi, Kshiitij; Naqvi, Savita; Pouye, Ade; Safi, Naqibullah; Chitnis, Ketan; Quereshi, Sabeeha

2016-12-23

Following the World Health Organization (WHO) declaration of a Public Health Emergency of International Concern regarding the Ebola outbreak in West Africa in July 2014, UNICEF was asked to co-lead, in coordination with WHO and the ministries of health of affected countries, the communication and social mobilization component-which UNICEF refers to as communication for development (C4D)-of the Ebola response. For the first time in an emergency setting, C4D was formally incorporated into each country's national response, alongside more typical components such as supplies and logistics, surveillance, and clinical care. This article describes the lessons learned about social mobilization and community engagement in the emergency response to the Ebola outbreak, with a particular focus on UNICEF's C4D work in Guinea, Liberia, and Sierra Leone. The lessons emerged through an assessment conducted by UNICEF using 4 methods: a literature review of key documents, meeting reports, and other articles; structured discussions conducted in June 2015 and October 2015 with UNICEF and civil society experts; an electronic survey, launched in October and November 2015, with staff from government, the UN, or any partner organization who worked on Ebola (N = 53); and key informant interviews (N = 5). After triangulating the findings from all data sources, we distilled lessons under 7 major domains: (1) strategy and decentralization: develop a comprehensive C4D strategy with communities at the center and decentralized programming to facilitate flexibility and adaptation to the local context; (2) coordination: establish C4D leadership with the necessary authority to coordinate between partners and enforce use of standard operating procedures as a central coordination and quality assurance tool; (3) entering and engaging communities: invest in key communication channels (such as radio) and trusted local community members; (4) messaging: adapt messages and strategies continually as patterns of the epidemic change over time; (5) partnerships: invest in strategic partnerships with community, religious leaders, journalists, radio stations, and partner organizations; (6) capacity building: support a network of local and international professionals with capacity for C4D who can be deployed rapidly; (7) data and performance monitoring: establish clear C4D process and impact indicators and strive for real-time data analysis and rapid feedback to communities and authorities to inform decision making. Ultimately, communication, community engagement, and social mobilization need to be formally placed within the global humanitarian response architecture with proper funding to effectively support future public health emergencies, which are as much a social as a health phenomenon. © Gillespie et al.

Market-oriented Programming Using Small-world Networks for Controlling Building Environments

NASA Astrophysics Data System (ADS)

Shigei, Noritaka; Miyajima, Hiromi; Osako, Tsukasa

The market model, which is one of the economic activity models, is modeled as an agent system, and applying the model to the resource allocation problem has been studied. For air conditioning control of building, which is one of the resource allocation problems, an effective method based on the agent system using auction has been proposed for traditional PID controller. On the other hand, it has been considered that this method is performed by decentralized control. However, its decentralization is not perfect, and its performace is not enough. In this paper, firstly, we propose a perfectly decentralized agent model and show its performance. Secondly, in order to improve the model, we propose the agent model based on small-world model. The effectiveness of the proposed model is shown by simulation.

A decentralized fuzzy C-means-based energy-efficient routing protocol for wireless sensor networks.

PubMed

Alia, Osama Moh'd

2014-01-01

Energy conservation in wireless sensor networks (WSNs) is a vital consideration when designing wireless networking protocols. In this paper, we propose a Decentralized Fuzzy Clustering Protocol, named DCFP, which minimizes total network energy dissipation to promote maximum network lifetime. The process of constructing the infrastructure for a given WSN is performed only once at the beginning of the protocol at a base station, which remains unchanged throughout the network's lifetime. In this initial construction step, a fuzzy C-means algorithm is adopted to allocate sensor nodes into their most appropriate clusters. Subsequently, the protocol runs its rounds where each round is divided into a CH-Election phase and a Data Transmission phase. In the CH-Election phase, the election of new cluster heads is done locally in each cluster where a new multicriteria objective function is proposed to enhance the quality of elected cluster heads. In the Data Transmission phase, the sensing and data transmission from each sensor node to their respective cluster head is performed and cluster heads in turn aggregate and send the sensed data to the base station. Simulation results demonstrate that the proposed protocol improves network lifetime, data delivery, and energy consumption compared to other well-known energy-efficient protocols.

A Decentralized Fuzzy C-Means-Based Energy-Efficient Routing Protocol for Wireless Sensor Networks

PubMed Central

2014-01-01

Energy conservation in wireless sensor networks (WSNs) is a vital consideration when designing wireless networking protocols. In this paper, we propose a Decentralized Fuzzy Clustering Protocol, named DCFP, which minimizes total network energy dissipation to promote maximum network lifetime. The process of constructing the infrastructure for a given WSN is performed only once at the beginning of the protocol at a base station, which remains unchanged throughout the network's lifetime. In this initial construction step, a fuzzy C-means algorithm is adopted to allocate sensor nodes into their most appropriate clusters. Subsequently, the protocol runs its rounds where each round is divided into a CH-Election phase and a Data Transmission phase. In the CH-Election phase, the election of new cluster heads is done locally in each cluster where a new multicriteria objective function is proposed to enhance the quality of elected cluster heads. In the Data Transmission phase, the sensing and data transmission from each sensor node to their respective cluster head is performed and cluster heads in turn aggregate and send the sensed data to the base station. Simulation results demonstrate that the proposed protocol improves network lifetime, data delivery, and energy consumption compared to other well-known energy-efficient protocols. PMID:25162060

Organically Grown Architectures: Creating Decentralized, Autonomous Systems by Embryomorphic Engineering

NASA Astrophysics Data System (ADS)

Doursat, René

Exploding growth growth in computational systems forces us to gradually replace rigid design and control with decentralization and autonomy. Information technologies will progress, instead, by"meta-designing" mechanisms of system self-assembly, self-regulation and evolution. Nature offers a great variety of efficient complex systems, in which numerous small elements form large-scale, adaptive patterns. The new engineering challenge is to recreate this self-organization and let it freely generate innovative designs under guidance. This article presents an original model of artificial system growth inspired by embryogenesis. A virtual organism is a lattice of cells that proliferate, migrate and self-pattern into differentiated domains. Each cell's fate is controlled by an internal gene regulatory network network. Embryomorphic engineering emphasizes hyperdistributed architectures, and their development as a prerequisite of evolutionary design.

Redundant manipulator techniques for partially decentralized path planning and control of a platoon of autonomous vehicles.

PubMed

Stilwell, Daniel J; Bishop, Bradley E; Sylvester, Caleb A

2005-08-01

An approach to real-time trajectory generation for platoons of autonomous vehicles is developed from well-known control techniques for redundant robotic manipulators. The partially decentralized structure of this approach permits each vehicle to independently compute its trajectory in real-time using only locally generated information and low-bandwidth feedback generated by a system exogenous to the platoon. Our work is motivated by applications for which communications bandwidth is severely limited, such for platoons of autonomous underwater vehicles. The communication requirements for our trajectory generation approach are independent of the number of vehicles in the platoon, enabling platoons composed of a large number of vehicles to be coordinated despite limited communication bandwidth.

A Markov Chain Approach to Probabilistic Swarm Guidance

NASA Technical Reports Server (NTRS)

Acikmese, Behcet; Bayard, David S.

2012-01-01

This paper introduces a probabilistic guidance approach for the coordination of swarms of autonomous agents. The main idea is to drive the swarm to a prescribed density distribution in a prescribed region of the configuration space. In its simplest form, the probabilistic approach is completely decentralized and does not require communication or collabo- ration between agents. Agents make statistically independent probabilistic decisions based solely on their own state, that ultimately guides the swarm to the desired density distribution in the configuration space. In addition to being completely decentralized, the probabilistic guidance approach has a novel autonomous self-repair property: Once the desired swarm density distribution is attained, the agents automatically repair any damage to the distribution without collaborating and without any knowledge about the damage.

Integrated long-range UAV/UGV collaborative target tracking

NASA Astrophysics Data System (ADS)

Moseley, Mark B.; Grocholsky, Benjamin P.; Cheung, Carol; Singh, Sanjiv

2009-05-01

Coordinated operations between unmanned air and ground assets allow leveraging of multi-domain sensing and increase opportunities for improving line of sight communications. While numerous military missions would benefit from coordinated UAV-UGV operations, foundational capabilities that integrate stove-piped tactical systems and share available sensor data are required and not yet available. iRobot, AeroVironment, and Carnegie Mellon University are working together, partially SBIR-funded through ARDEC's small unit network lethality initiative, to develop collaborative capabilities for surveillance, targeting, and improved communications based on PackBot UGV and Raven UAV platforms. We integrate newly available technologies into computational, vision, and communications payloads and develop sensing algorithms to support vision-based target tracking. We first simulated and then applied onto real tactical platforms an implementation of Decentralized Data Fusion, a novel technique for fusing track estimates from PackBot and Raven platforms for a moving target in an open environment. In addition, system integration with AeroVironment's Digital Data Link onto both air and ground platforms has extended our capabilities in communications range to operate the PackBot as well as in increased video and data throughput. The system is brought together through a unified Operator Control Unit (OCU) for the PackBot and Raven that provides simultaneous waypoint navigation and traditional teleoperation. We also present several recent capability accomplishments toward PackBot-Raven coordinated operations, including single OCU display design and operation, early target track results, and Digital Data Link integration efforts, as well as our near-term capability goals.

The Rise of the CISO

ERIC Educational Resources Information Center

Gale, Doug

2007-01-01

The late 1980s was an exciting time to be a CIO in higher education. Computing was being decentralized as microcomputers replaced mainframes, networking was emerging, and the National Science Foundation Network (NSFNET) was introducing the concept of an "internet" to hundreds of thousands of new users. Security wasn't much of an issue;…

Critical Thinking about Literature through Computer Networking.

ERIC Educational Resources Information Center

Long, Thomas L.; Pedersen, Christine

A computer-oriented, classroom-based research project was conducted at Thomas Nelson Community College in Hampton, Virginia, to explore the ways in which students in a composition and literature class might use a local area network (LAN) as a catalyst to critical thinking, to construct a decentralized classroom, and to use various forms of…

The ecology of markets.

PubMed Central

Nordhaus, W D

1992-01-01

Economies are sometimes viewed as analogous to ecological systems in which "everything is connected to everything else." In complex modern economies, the question arises whether the market mechanism can appropriately coordinate all the interconnections or whether instead some supramarket body is needed to coordinate the vast web of human activities. This study describes how an idealized decentralized competitive market in fact coordinates the different economic organisms in an efficient manner. The problems of pollution and other externalities can undo the efficient outcome unless corrected by appropriate property rights or corrective taxes. But in closing the economic circle, the internalized economy does not actually need to close the natural cycles by linking up all physical flows through recycling. PMID:11607264

An Effective and Robust Decentralized Target Tracking Scheme in Wireless Camera Sensor Networks.

PubMed

Fu, Pengcheng; Cheng, Yongbo; Tang, Hongying; Li, Baoqing; Pei, Jun; Yuan, Xiaobing

2017-03-20

In this paper, we propose an effective and robust decentralized tracking scheme based on the square root cubature information filter (SRCIF) to balance the energy consumption and tracking accuracy in wireless camera sensor networks (WCNs). More specifically, regarding the characteristics and constraints of camera nodes in WCNs, some special mechanisms are put forward and integrated in this tracking scheme. First, a decentralized tracking approach is adopted so that the tracking can be implemented energy-efficiently and steadily. Subsequently, task cluster nodes are dynamically selected by adopting a greedy on-line decision approach based on the defined contribution decision (CD) considering the limited energy of camera nodes. Additionally, we design an efficient cluster head (CH) selection mechanism that casts such selection problem as an optimization problem based on the remaining energy and distance-to-target. Finally, we also perform analysis on the target detection probability when selecting the task cluster nodes and their CH, owing to the directional sensing and observation limitations in field of view (FOV) of camera nodes in WCNs. From simulation results, the proposed tracking scheme shows an obvious improvement in balancing the energy consumption and tracking accuracy over the existing methods.

An Effective and Robust Decentralized Target Tracking Scheme in Wireless Camera Sensor Networks

PubMed Central

Fu, Pengcheng; Cheng, Yongbo; Tang, Hongying; Li, Baoqing; Pei, Jun; Yuan, Xiaobing

2017-01-01

In this paper, we propose an effective and robust decentralized tracking scheme based on the square root cubature information filter (SRCIF) to balance the energy consumption and tracking accuracy in wireless camera sensor networks (WCNs). More specifically, regarding the characteristics and constraints of camera nodes in WCNs, some special mechanisms are put forward and integrated in this tracking scheme. First, a decentralized tracking approach is adopted so that the tracking can be implemented energy-efficiently and steadily. Subsequently, task cluster nodes are dynamically selected by adopting a greedy on-line decision approach based on the defined contribution decision (CD) considering the limited energy of camera nodes. Additionally, we design an efficient cluster head (CH) selection mechanism that casts such selection problem as an optimization problem based on the remaining energy and distance-to-target. Finally, we also perform analysis on the target detection probability when selecting the task cluster nodes and their CH, owing to the directional sensing and observation limitations in field of view (FOV) of camera nodes in WCNs. From simulation results, the proposed tracking scheme shows an obvious improvement in balancing the energy consumption and tracking accuracy over the existing methods. PMID:28335537

Spatial optimization for decentralized non-potable water reuse

NASA Astrophysics Data System (ADS)

Kavvada, Olga; Nelson, Kara L.; Horvath, Arpad

2018-06-01

Decentralization has the potential to reduce the scale of the piped distribution network needed to enable non-potable water reuse (NPR) in urban areas by producing recycled water closer to its point of use. However, tradeoffs exist between the economies of scale of treatment facilities and the size of the conveyance infrastructure, including energy for upgradient distribution of recycled water. To adequately capture the impacts from distribution pipes and pumping requirements, site-specific conditions must be accounted for. In this study, a generalized framework (a heuristic modeling approach using geospatial algorithms) is developed that estimates the financial cost, the energy use, and the greenhouse gas emissions associated with NPR (for toilet flushing) as a function of scale of treatment and conveyance networks with the goal of determining the optimal degree of decentralization. A decision-support platform is developed to assess and visualize NPR system designs considering topography, economies of scale, and building size. The platform can be used for scenario development to explore the optimal system size based on the layout of current or new buildings. The model also promotes technology innovation by facilitating the systems-level comparison of options to lower costs, improve energy efficiency, and lower greenhouse gas emissions.

Centralized Coordination of Decentralized Assistance for Patients with Gestational Trophoblastic Disease in Brazil: A Viable Strategy for Developing Countries.

PubMed

Braga, Antonio; Burlá, Marcelo; Freitas, Fernanda; Uberti, Elza; Viggiano, Mauricio; Sun, Sue Yazaki; Maestá, Izildinha; Elias, Kevin M; Berkowitz, Ross S

2016-01-01

To report on the Brazilian Association of Gestational Trophoblastic Disease's (GTD) formation of a network of regional care at specialized centers for women with GTD. We developed a questionnaire composed of 15 questions, which was sent by email to the 38 Brazilian GTD Reference Center (BGTDRC) Directors who are members of the Brazilian Association of GTD, in order to characterize the professionals involved in the care of patients with GTD and the type of assistance provided. The Directors of the BGTDRCs are usually specialists in Gynecology and Obstetrics (97%), with a median experience of a decade in treating women with GTD. The BGTDRCs are linked to university hospitals in 75% of centers and provide completely free medical care in 87%. However, 52% of centers do not perform chemotherapy in their reference center, and patients are referred elsewhere for chemotherapy. Despite some difficulties, the rate of patients lost to follow-up before human chorionic gonadotropin remission is 9%, and the GTD mortality rate is 0.9%. Due to large regional disparities, the BGTDRCs are not uniformly organized. However, under the coordination of the Brazilian Association of GTD there is now strong communication and collaboration among reference centers, which has significantly advanced both patient care and research into the management of these diseases.

Robustness analysis of complex networks with power decentralization strategy via flow-sensitive centrality against cascading failures

NASA Astrophysics Data System (ADS)

Guo, Wenzhang; Wang, Hao; Wu, Zhengping

2018-03-01

Most existing cascading failure mitigation strategy of power grids based on complex network ignores the impact of electrical characteristics on dynamic performance. In this paper, the robustness of the power grid under a power decentralization strategy is analysed through cascading failure simulation based on AC flow theory. The flow-sensitive (FS) centrality is introduced by integrating topological features and electrical properties to help determine the siting of the generation nodes. The simulation results of the IEEE-bus systems show that the flow-sensitive centrality method is a more stable and accurate approach and can enhance the robustness of the network remarkably. Through the study of the optimal flow-sensitive centrality selection for different networks, we find that the robustness of the network with obvious small-world effect depends more on contribution of the generation nodes detected by community structure, otherwise, contribution of the generation nodes with important influence on power flow is more critical. In addition, community structure plays a significant role in balancing the power flow distribution and further slowing the propagation of failures. These results are useful in power grid planning and cascading failure prevention.

MEDLARS and the Library Community

PubMed Central

Adams, Scott

1964-01-01

The intention of the National Library of Medicine is to share with other libraries the products and the capabilities developed by the MEDLARS system. MEDLARS will provide bibliographic services of use to other libraries from the central system. The decentralization of the central system to permit libraries with access to computers to establish local machine retrieval systems is also indicated. The implications of such decentralization for the American medical library network and its effect on library evolution are suggested, as are the implications for international development of mechanized storage and retrieval systems. PMID:14119289

On the topological structure of multinationals network

NASA Astrophysics Data System (ADS)

Joyez, Charlie

2017-05-01

This paper uses a weighted network analysis to examine the structure of multinationals' implantation countries network. Based on French firm-level dataset of multinational enterprises (MNEs) the network analysis provides information on each country position in the network and in internationalization strategies of French MNEs through connectivity preferences among the nodes. The paper also details network-wide features and their recent evolution toward a more decentralized structure. While much has been said on international trade network, this paper shows that multinational firms' studies would also benefit from network analysis, notably by investigating the sensitivity of the network construction to firm heterogeneity.

The Marketing of Education in a Coordinated Decentralised Context: Alfred P. Sloan Revisited.

ERIC Educational Resources Information Center

Watkins, Peter E.

This paper argues that a useful way of analyzing the current moves to locate education within a decentralized framework of schools competing for educational consumers is to return to the founders of managerialism. In particular, this paper suggests that by returning to the point of production, the "mutilated rationality" (Habermas) of…

Quantifying Risk for Decentralized Offensive Cyber Operations

DTIC Science & Technology

2017-06-01

information. Additionally, radio communications equipment were reevaluated in order to provide longer ranges, last longer on battery power, and be...every other device monitoring that radio frequency . Additionally, wireless signals are limited by distance, the construction materials in walls... communications , socio-psychological, and personality factors in the maintenance of crew coordination. Aviation, Space, and Environmental Medicine, 53( 11

Decentralized event-triggered consensus control strategy for leader-follower networked systems

NASA Astrophysics Data System (ADS)

Zhang, Shouxu; Xie, Duosi; Yan, Weisheng

2017-08-01

In this paper, the consensus problem of leader-follower networked systems is addressed. At first, a centralized and a decentralized event-triggered control strategy are proposed, which make the control actuators of followers update at aperiodic invent interval. In particular, the latter one makes each follower requires the local information only. After that, an improved triggering function that only uses the follower's own information and the neighbors' states at their latest event instants is developed to relax the requirement of the continuous state of the neighbors. In addition, the strategy does not require the information of the topology, nor the eigenvalues of the Laplacian matrix. And if the follower does not have direct connection to the leader, the leader's information is not required either. It is analytically shown that by using the proposed strategy the leader-follower networked system is able to reach consensus without continuous communication among followers. Simulation examples are given to show effectiveness of the proposed control strategy.

Analyzing the Impact of Storage Shortage on Data Availability in Decentralized Online Social Networks

PubMed Central

He, Ligang; Liao, Xiangke; Huang, Chenlin

2014-01-01

Maintaining data availability is one of the biggest challenges in decentralized online social networks (DOSNs). The existing work often assumes that the friends of a user can always contribute to the sufficient storage capacity to store all data. However, this assumption is not always true in today's online social networks (OSNs) due to the fact that nowadays the users often use the smart mobile devices to access the OSNs. The limitation of the storage capacity in mobile devices may jeopardize the data availability. Therefore, it is desired to know the relation between the storage capacity contributed by the OSN users and the level of data availability that the OSNs can achieve. This paper addresses this issue. In this paper, the data availability model over storage capacity is established. Further, a novel method is proposed to predict the data availability on the fly. Extensive simulation experiments have been conducted to evaluate the effectiveness of the data availability model and the on-the-fly prediction. PMID:24892095

Belief Function Based Decision Fusion for Decentralized Target Classification in Wireless Sensor Networks

PubMed Central

Zhang, Wenyu; Zhang, Zhenjiang

2015-01-01

Decision fusion in sensor networks enables sensors to improve classification accuracy while reducing the energy consumption and bandwidth demand for data transmission. In this paper, we focus on the decentralized multi-class classification fusion problem in wireless sensor networks (WSNs) and a new simple but effective decision fusion rule based on belief function theory is proposed. Unlike existing belief function based decision fusion schemes, the proposed approach is compatible with any type of classifier because the basic belief assignments (BBAs) of each sensor are constructed on the basis of the classifier’s training output confusion matrix and real-time observations. We also derive explicit global BBA in the fusion center under Dempster’s combinational rule, making the decision making operation in the fusion center greatly simplified. Also, sending the whole BBA structure to the fusion center is avoided. Experimental results demonstrate that the proposed fusion rule has better performance in fusion accuracy compared with the naïve Bayes rule and weighted majority voting rule. PMID:26295399

Analyzing the impact of storage shortage on data availability in decentralized online social networks.

PubMed

Fu, Songling; He, Ligang; Liao, Xiangke; Li, Kenli; Huang, Chenlin

2014-01-01

Maintaining data availability is one of the biggest challenges in decentralized online social networks (DOSNs). The existing work often assumes that the friends of a user can always contribute to the sufficient storage capacity to store all data. However, this assumption is not always true in today's online social networks (OSNs) due to the fact that nowadays the users often use the smart mobile devices to access the OSNs. The limitation of the storage capacity in mobile devices may jeopardize the data availability. Therefore, it is desired to know the relation between the storage capacity contributed by the OSN users and the level of data availability that the OSNs can achieve. This paper addresses this issue. In this paper, the data availability model over storage capacity is established. Further, a novel method is proposed to predict the data availability on the fly. Extensive simulation experiments have been conducted to evaluate the effectiveness of the data availability model and the on-the-fly prediction.

A federated information management system for the Deep Space Network. M.S. Thesis - Univ. of Southern California

NASA Technical Reports Server (NTRS)

Dobinson, E.

1982-01-01

General requirements for an information management system for the deep space network (DSN) are examined. A concise review of available database management system technology is presented. It is recommended that a federation of logically decentralized databases be implemented for the Network Information Management System of the DSN. Overall characteristics of the federation are specified, as well as reasons for adopting this approach.

LEOPACK The integrated services communications system based on LEO satellites

NASA Astrophysics Data System (ADS)

Negoda, A.; Bunin, S.; Bushuev, E.; Dranovsky, V.

LEOPACK is yet another LEO satellite project which provides global integrated services for 'business' communications. It utilizes packet rather then circuit switching in both terrestrial and satellite chains as well as cellular approach for frequencies use. Original multiple access protocols and decentralized network control make it possible to organize regionally or logically independent and world-wide networks. Relatively small number of satellites (28) provides virtually global network coverage.

Distributed processing method for arbitrary view generation in camera sensor network

NASA Astrophysics Data System (ADS)

Tehrani, Mehrdad P.; Fujii, Toshiaki; Tanimoto, Masayuki

2003-05-01

Camera sensor network as a new advent of technology is a network that each sensor node can capture video signals, process and communicate them with other nodes. The processing task in this network is to generate arbitrary view, which can be requested from central node or user. To avoid unnecessary communication between nodes in camera sensor network and speed up the processing time, we have distributed the processing tasks between nodes. In this method, each sensor node processes part of interpolation algorithm to generate the interpolated image with local communication between nodes. The processing task in camera sensor network is ray-space interpolation, which is an object independent method and based on MSE minimization by using adaptive filtering. Two methods were proposed for distributing processing tasks, which are Fully Image Shared Decentralized Processing (FIS-DP), and Partially Image Shared Decentralized Processing (PIS-DP), to share image data locally. Comparison of the proposed methods with Centralized Processing (CP) method shows that PIS-DP has the highest processing speed after FIS-DP, and CP has the lowest processing speed. Communication rate of CP and PIS-DP is almost same and better than FIS-DP. So, PIS-DP is recommended because of its better performance than CP and FIS-DP.

Decentralized Orchestration of Composite Ogc Web Processing Services in the Cloud

NASA Astrophysics Data System (ADS)

Xiao, F.; Shea, G. Y. K.; Cao, J.

2016-09-01

Current web-based GIS or RS applications generally rely on centralized structure, which has inherent drawbacks such as single points of failure, network congestion, and data inconsistency, etc. The inherent disadvantages of traditional GISs need to be solved for new applications on Internet or Web. Decentralized orchestration offers performance improvements in terms of increased throughput and scalability and lower response time. This paper investigates build time and runtime issues related to decentralized orchestration of composite geospatial processing services based on OGC WPS standard specification. A case study of dust storm detection was demonstrated to evaluate the proposed method and the experimental results indicate that the method proposed in this study is effective for its ability to produce the high quality solution at a low cost of communications for geospatial processing service composition problem.

Web-based international studies in limited populations of pediatric leukemia.

PubMed

Valsecchi, Maria Grazia; Silvestri, Daniela; Covezzoli, Anna; De Lorenzo, Paola

2008-02-01

Recent progress in cancer research leads to the characterization of small subgroups of patients by genetic/biological features. Clinical studies in this setting are frequently promoted by international networks of independent researchers and are limited by practical and methodological constraints, not least the regulations recently issued by national and international institutions (EU Directive 2001/20/EC). We reviewed various methods in the design of international multicenter studies, with focus on randomized clinical trials. This paper reports our experience in planning and conducting international studies in childhood leukemia. We applied a decentralized study conduct based on a two-level structure, comprising a national and an international coordinating level. For the more recent trials this structure was implemented as a web-based system. This approach accommodates major legal requirements (e.g., safety reporting) and ensures Good Clinical Practice principles by implementing risk-oriented monitoring procedures. Setting up international non-commercial trials is increasingly complicated. Still, they are strongly needed for answering relevant questions in limited populations. (c) 2007 Wiley-Liss, Inc.

Disaster risk reduction capacity assessment for precarious settlements in Guatemala City.

PubMed

Miles, Scott B; Green, Rebekah A; Svekla, Walter

2012-07-01

This study presents findings of an institutional capacity analysis of urban disaster risk reduction for informal settlements in the Guatemala Metropolitan Region. It uses a resource access perspective of vulnerability, actor-network theory, and qualitative data collection. The analysis reveals that there is interest in disaster risk reduction for the informal settlements; however, there is little in the way of direct financial or oversight relationships between informal settlement residents and all other actors. Respondents observed that informal settlements would probably remain inhabited; thus, there is a need for disaster risk reduction within these settlements. Disaster risk reduction capacity for informal settlements exists and can be further leveraged, as long as steps are taken to ensure appropriate access to and control of resources and oversight. Further, the nascent institutional arrangements should be strengthened through increased communication and coordination between actors, a decentralization of oversight and financial relationships, and mediation of identified resource conflicts. © 2012 The Author(s). Journal compilation © Overseas Development Institute, 2012.

Crossbar Switches For Optical Data-Communication Networks

NASA Technical Reports Server (NTRS)

Monacos, Steve P.

1994-01-01

Optoelectronic and electro-optical crossbar switches called "permutation engines" (PE's) developed to route packets of data through fiber-optic communication networks. Basic network concept described in "High-Speed Optical Wide-Area Data-Communication Network" (NPO-18983). Nonblocking operation achieved by decentralized switching and control scheme. Each packet routed up or down in each column of this 5-input/5-output permutation engine. Routing algorithm ensures each packet arrives at its designated output port without blocking any other packet that does not contend for same output port.

Ophiuroid robot that self-organizes periodic and non-periodic arm movements.

PubMed

Kano, Takeshi; Suzuki, Shota; Watanabe, Wataru; Ishiguro, Akio

2012-09-01

Autonomous decentralized control is a key concept for understanding the mechanism underlying adaptive and versatile locomotion of animals. Although the design of an autonomous decentralized control system that ensures adaptability by using coupled oscillators has been proposed previously, it cannot comprehensively reproduce the versatility of animal behaviour. To tackle this problem, we focus on using ophiuroids as a simple model that exhibits versatile locomotion including periodic and non-periodic arm movements. Our existing model for ophiuroid locomotion uses an active rotator model that describes both oscillatory and excitatory properties. In this communication, we develop an ophiuroid robot to confirm the validity of this proposed model in the real world. We show that the robot travels by successfully coordinating periodic and non-periodic arm movements in response to external stimuli.

Simultaneous Education for Women and Girls. Report of a Project.

ERIC Educational Resources Information Center

United Nations Educational, Scientific, and Cultural Organization, Bangkok (Thailand). Regional Office for Education in Asia and the Pacific.

This project focuses on non-formal and adult education for women in rural areas of Uttar Pradesh, India. The objectives of the project were: (1) to provide non-formal education to girls and adult education to women in a coordinated manner; (2) to raise civic and social awareness of women; (3) to decentralize planning and implementation of programs…

Cooperative Learning for Distributed In-Network Traffic Classification

NASA Astrophysics Data System (ADS)

Joseph, S. B.; Loo, H. R.; Ismail, I.; Andromeda, T.; Marsono, M. N.

2017-04-01

Inspired by the concept of autonomic distributed/decentralized network management schemes, we consider the issue of information exchange among distributed network nodes to network performance and promote scalability for in-network monitoring. In this paper, we propose a cooperative learning algorithm for propagation and synchronization of network information among autonomic distributed network nodes for online traffic classification. The results show that network nodes with sharing capability perform better with a higher average accuracy of 89.21% (sharing data) and 88.37% (sharing clusters) compared to 88.06% for nodes without cooperative learning capability. The overall performance indicates that cooperative learning is promising for distributed in-network traffic classification.

Wave scheduling - Decentralized scheduling of task forces in multicomputers

NASA Technical Reports Server (NTRS)

Van Tilborg, A. M.; Wittie, L. D.

1984-01-01

Decentralized operating systems that control large multicomputers need techniques to schedule competing parallel programs called task forces. Wave scheduling is a probabilistic technique that uses a hierarchical distributed virtual machine to schedule task forces by recursively subdividing and issuing wavefront-like commands to processing elements capable of executing individual tasks. Wave scheduling is highly resistant to processing element failures because it uses many distributed schedulers that dynamically assign scheduling responsibilities among themselves. The scheduling technique is trivially extensible as more processing elements join the host multicomputer. A simple model of scheduling cost is used by every scheduler node to distribute scheduling activity and minimize wasted processing capacity by using perceived workload to vary decentralized scheduling rules. At low to moderate levels of network activity, wave scheduling is only slightly less efficient than a central scheduler in its ability to direct processing elements to accomplish useful work.

Non-Orthogonal Random Access in MIMO Cognitive Radio Networks: Beamforming, Power Allocation, and Opportunistic Transmission

PubMed Central

Lin, Huifa; Shin, Won-Yong

2017-01-01

We study secondary random access in multi-input multi-output cognitive radio networks, where a slotted ALOHA-type protocol and successive interference cancellation are used. We first introduce three types of transmit beamforming performed by secondary users, where multiple antennas are used to suppress the interference at the primary base station and/or to increase the received signal power at the secondary base station. Then, we show a simple decentralized power allocation along with the equivalent single-antenna conversion. To exploit the multiuser diversity gain, an opportunistic transmission protocol is proposed, where the secondary users generating less interference are opportunistically selected, resulting in a further reduction of the interference temperature. The proposed methods are validated via computer simulations. Numerical results show that increasing the number of transmit antennas can greatly reduce the interference temperature, while increasing the number of receive antennas leads to a reduction of the total transmit power. Optimal parameter values of the opportunistic transmission protocol are examined according to three types of beamforming and different antenna configurations, in terms of maximizing the cognitive transmission capacity. All the beamforming, decentralized power allocation, and opportunistic transmission protocol are performed by the secondary users in a decentralized manner, thus resulting in an easy implementation in practice. PMID:28076402

Decentralized Optimal Dispatch of Photovoltaic Inverters in Residential Distribution Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dall'Anese, Emiliano; Dhople, Sairaj V.; Johnson, Brian B.

Summary form only given. Decentralized methods for computing optimal real and reactive power setpoints for residential photovoltaic (PV) inverters are developed in this paper. It is known that conventional PV inverter controllers, which are designed to extract maximum power at unity power factor, cannot address secondary performance objectives such as voltage regulation and network loss minimization. Optimal power flow techniques can be utilized to select which inverters will provide ancillary services, and to compute their optimal real and reactive power setpoints according to well-defined performance criteria and economic objectives. Leveraging advances in sparsity-promoting regularization techniques and semidefinite relaxation, this papermore » shows how such problems can be solved with reduced computational burden and optimality guarantees. To enable large-scale implementation, a novel algorithmic framework is introduced - based on the so-called alternating direction method of multipliers - by which optimal power flow-type problems in this setting can be systematically decomposed into sub-problems that can be solved in a decentralized fashion by the utility and customer-owned PV systems with limited exchanges of information. Since the computational burden is shared among multiple devices and the requirement of all-to-all communication can be circumvented, the proposed optimization approach scales favorably to large distribution networks.« less

Non-Orthogonal Random Access in MIMO Cognitive Radio Networks: Beamforming, Power Allocation, and Opportunistic Transmission.

PubMed

Lin, Huifa; Shin, Won-Yong

2017-01-01

We study secondary random access in multi-input multi-output cognitive radio networks, where a slotted ALOHA-type protocol and successive interference cancellation are used. We first introduce three types of transmit beamforming performed by secondary users, where multiple antennas are used to suppress the interference at the primary base station and/or to increase the received signal power at the secondary base station. Then, we show a simple decentralized power allocation along with the equivalent single-antenna conversion. To exploit the multiuser diversity gain, an opportunistic transmission protocol is proposed, where the secondary users generating less interference are opportunistically selected, resulting in a further reduction of the interference temperature. The proposed methods are validated via computer simulations. Numerical results show that increasing the number of transmit antennas can greatly reduce the interference temperature, while increasing the number of receive antennas leads to a reduction of the total transmit power. Optimal parameter values of the opportunistic transmission protocol are examined according to three types of beamforming and different antenna configurations, in terms of maximizing the cognitive transmission capacity. All the beamforming, decentralized power allocation, and opportunistic transmission protocol are performed by the secondary users in a decentralized manner, thus resulting in an easy implementation in practice.

The Setting-up of Multi-Site School Collaboratives: The Benefits of This Organizational Reform in Terms of Networking Opportunities and Their Effects

ERIC Educational Resources Information Center

Mifsud, Denise

2015-01-01

This article, which is set within the Maltese education scenario of unfolding decentralization through the setting-up of multi-site school collaboratives (legally termed "colleges") via a policy mandate, explores a particular aspect of this reform--that of "networking". This is examined in terms of the potential for…

Distributed Computing Environment for Mine Warfare Command

DTIC Science & Technology

1993-06-01

based system to a decentralized network of personal computers over the past several years. This thesis analyzes the progress of the evolution as of May of...network of personal computers over the past several years. This thesis analyzes the progress of the evolution as of May of 1992. The building blocks of a...85 A. BACKGROUND ............. .................. 85 B. PAST ENVIRONMENT ........... ............... 86 C. PRESENT ENVIRONMENT

Decentralized System Control.

DTIC Science & Technology

1986-04-01

a Local Area Network Environment. Submitted for Publication. 1982. [Barrnger 791 Barringer . H,. P. C. Capon, and R . Phillips. The Portable Compiling...configuration and hardware. [Chesley 81 Chesley, Harry R . and Bruce V. Hunt., % Squire - A Communications-Oriented Operating System. Computer Networks 5(2...copying the information. Transfers between machines and copying " - r pages as necemry. [Nelson 80] Nelson, Bruce Jay. Remote Procedure Call. PhD Thesis

Generic, scalable and decentralized fault detection for robot swarms.

PubMed

Tarapore, Danesh; Christensen, Anders Lyhne; Timmis, Jon

2017-01-01

Robot swarms are large-scale multirobot systems with decentralized control which means that each robot acts based only on local perception and on local coordination with neighboring robots. The decentralized approach to control confers number of potential benefits. In particular, inherent scalability and robustness are often highlighted as key distinguishing features of robot swarms compared with systems that rely on traditional approaches to multirobot coordination. It has, however, been shown that swarm robotics systems are not always fault tolerant. To realize the robustness potential of robot swarms, it is thus essential to give systems the capacity to actively detect and accommodate faults. In this paper, we present a generic fault-detection system for robot swarms. We show how robots with limited and imperfect sensing capabilities are able to observe and classify the behavior of one another. In order to achieve this, the underlying classifier is an immune system-inspired algorithm that learns to distinguish between normal behavior and abnormal behavior online. Through a series of experiments, we systematically assess the performance of our approach in a detailed simulation environment. In particular, we analyze our system's capacity to correctly detect robots with faults, false positive rates, performance in a foraging task in which each robot exhibits a composite behavior, and performance under perturbations of the task environment. Results show that our generic fault-detection system is robust, that it is able to detect faults in a timely manner, and that it achieves a low false positive rate. The developed fault-detection system has the potential to enable long-term autonomy for robust multirobot systems, thus increasing the usefulness of robots for a diverse repertoire of upcoming applications in the area of distributed intelligent automation.

Generic, scalable and decentralized fault detection for robot swarms

PubMed Central

Christensen, Anders Lyhne; Timmis, Jon

2017-01-01

Robot swarms are large-scale multirobot systems with decentralized control which means that each robot acts based only on local perception and on local coordination with neighboring robots. The decentralized approach to control confers number of potential benefits. In particular, inherent scalability and robustness are often highlighted as key distinguishing features of robot swarms compared with systems that rely on traditional approaches to multirobot coordination. It has, however, been shown that swarm robotics systems are not always fault tolerant. To realize the robustness potential of robot swarms, it is thus essential to give systems the capacity to actively detect and accommodate faults. In this paper, we present a generic fault-detection system for robot swarms. We show how robots with limited and imperfect sensing capabilities are able to observe and classify the behavior of one another. In order to achieve this, the underlying classifier is an immune system-inspired algorithm that learns to distinguish between normal behavior and abnormal behavior online. Through a series of experiments, we systematically assess the performance of our approach in a detailed simulation environment. In particular, we analyze our system’s capacity to correctly detect robots with faults, false positive rates, performance in a foraging task in which each robot exhibits a composite behavior, and performance under perturbations of the task environment. Results show that our generic fault-detection system is robust, that it is able to detect faults in a timely manner, and that it achieves a low false positive rate. The developed fault-detection system has the potential to enable long-term autonomy for robust multirobot systems, thus increasing the usefulness of robots for a diverse repertoire of upcoming applications in the area of distributed intelligent automation. PMID:28806756

Building and Rebuilding: The National Public Health Laboratory Systems and Services Before and After the Earthquake and Cholera Epidemic, Haiti, 2009-2015.

PubMed

Jean Louis, Frantz; Buteau, Josiane; Boncy, Jacques; Anselme, Renette; Stanislas, Magalie; Nagel, Mary C; Juin, Stanley; Charles, Macarthur; Burris, Robert; Antoine, Eva; Yang, Chunfu; Kalou, Mireille; Vertefeuille, John; Marston, Barbara J; Lowrance, David W; Deyde, Varough

2017-10-01

Before the 2010 devastating earthquake and cholera outbreak, Haiti's public health laboratory systems were weak and services were limited. There was no national laboratory strategic plan and only minimal coordination across the laboratory network. Laboratory capacity was further weakened by the destruction of over 25 laboratories and testing sites at the departmental and peripheral levels and the loss of life among the laboratory health-care workers. However, since 2010, tremendous progress has been made in building stronger laboratory infrastructure and training a qualified public health laboratory workforce across the country, allowing for decentralization of access to quality-assured services. Major achievements include development and implementation of a national laboratory strategic plan with a formalized and strengthened laboratory network; introduction of automation of testing to ensure better quality of results and diversify the menu of tests to effectively respond to outbreaks; expansion of molecular testing for tuberculosis, human immunodeficiency virus, malaria, diarrheal and respiratory diseases; establishment of laboratory-based surveillance of epidemic-prone diseases; and improvement of the overall quality of testing. Nonetheless, the progress and gains made remain fragile and require the full ownership and continuous investment from the Haitian government to sustain these successes and achievements.

Building and Rebuilding: The National Public Health Laboratory Systems and Services Before and After the Earthquake and Cholera Epidemic, Haiti, 2009–2015

PubMed Central

Jean Louis, Frantz; Buteau, Josiane; Boncy, Jacques; Anselme, Renette; Stanislas, Magalie; Nagel, Mary C.; Juin, Stanley; Charles, Macarthur; Burris, Robert; Antoine, Eva; Yang, Chunfu; Kalou, Mireille; Vertefeuille, John; Marston, Barbara J.; Lowrance, David W.; Deyde, Varough

2017-01-01

Abstract. Before the 2010 devastating earthquake and cholera outbreak, Haiti’s public health laboratory systems were weak and services were limited. There was no national laboratory strategic plan and only minimal coordination across the laboratory network. Laboratory capacity was further weakened by the destruction of over 25 laboratories and testing sites at the departmental and peripheral levels and the loss of life among the laboratory health-care workers. However, since 2010, tremendous progress has been made in building stronger laboratory infrastructure and training a qualified public health laboratory workforce across the country, allowing for decentralization of access to quality-assured services. Major achievements include development and implementation of a national laboratory strategic plan with a formalized and strengthened laboratory network; introduction of automation of testing to ensure better quality of results and diversify the menu of tests to effectively respond to outbreaks; expansion of molecular testing for tuberculosis, human immunodeficiency virus, malaria, diarrheal and respiratory diseases; establishment of laboratory-based surveillance of epidemic-prone diseases; and improvement of the overall quality of testing. Nonetheless, the progress and gains made remain fragile and require the full ownership and continuous investment from the Haitian government to sustain these successes and achievements. PMID:29064354

Self-* properties through gossiping.

PubMed

Babaoglu, Ozalp; Jelasity, Márk

2008-10-28

As computer systems have become more complex, numerous competing approaches have been proposed for these systems to self-configure, self-manage, self-repair, etc. such that human intervention in their operation can be minimized. In ubiquitous systems, this has always been a central issue as well. In this paper, we overview techniques to implement self-* properties in large-scale, decentralized networks through bio-inspired techniques in general, and gossip-based algorithms in particular. We believe that gossip-based algorithms could be an important inspiration for solving problems in ubiquitous computing as well. As an example, we outline a novel approach to arrange large numbers of mobile agents (e.g. vehicles, rescue teams carrying mobile devices) into different formations in a totally decentralized manner. The approach is inspired by the biological mechanism of cell sorting via differential adhesion, as well as by our earlier work in self-organizing peer-to-peer overlay networks.

OTACT: ONU Turning with Adaptive Cycle Times in Long-Reach PONs

NASA Astrophysics Data System (ADS)

Zare, Sajjad; Ghaffarpour Rahbar, Akbar

2015-01-01

With the expansion of PON networks as Long-Reach PON (LR-PON) networks, the problem of degrading the efficiency of centralized bandwidth allocation algorithms threatens this network due to high propagation delay. This is because these algorithms are based on bandwidth negotiation messages frequently exchanged between the optical line terminal (OLT) in the Central Office and optical network units (ONUs) near the users, which become seriously delayed when the network is extended. To solve this problem, some decentralized algorithms are proposed based on bandwidth negotiation messages frequently exchanged between the Remote Node (RN)/Local Exchange (LX) and ONUs near the users. The network has a relatively high delay since there are relatively large distances between RN/LX and ONUs, and therefore, control messages should travel twice between ONUs and RN/LX in order to go from one ONU to another ONU. In this paper, we propose a novel framework, called ONU Turning with Adaptive Cycle Times (OTACT), that uses Power Line Communication (PLC) to connect two adjacent ONUs. Since there is a large population density in urban areas, ONUs are closer to each other. Thus, the efficiency of the proposed method is high. We investigate the performance of the proposed scheme in contrast with other decentralized schemes under the worst case conditions. Simulation results show that the average upstream packet delay can be decreased under the proposed scheme.

A Decentralized Framework for Multi-Agent Robotic Systems

PubMed Central

2018-01-01

Over the past few years, decentralization of multi-agent robotic systems has become an important research area. These systems do not depend on a central control unit, which enables the control and assignment of distributed, asynchronous and robust tasks. However, in some cases, the network communication process between robotic agents is overlooked, and this creates a dependency for each agent to maintain a permanent link with nearby units to be able to fulfill its goals. This article describes a communication framework, where each agent in the system can leave the network or accept new connections, sending its information based on the transfer history of all nodes in the network. To this end, each agent needs to comply with four processes to participate in the system, plus a fifth process for data transfer to the nearest nodes that is based on Received Signal Strength Indicator (RSSI) and data history. To validate this framework, we use differential robotic agents and a monitoring agent to generate a topological map of an environment with the presence of obstacles. PMID:29389849

Some aspects of control of a large-scale dynamic system

NASA Technical Reports Server (NTRS)

Aoki, M.

1975-01-01

Techniques of predicting and/or controlling the dynamic behavior of large scale systems are discussed in terms of decentralized decision making. Topics discussed include: (1) control of large scale systems by dynamic team with delayed information sharing; (2) dynamic resource allocation problems by a team (hierarchical structure with a coordinator); and (3) some problems related to the construction of a model of reduced dimension.

Decentral Smart Grid Control

NASA Astrophysics Data System (ADS)

Schäfer, Benjamin; Matthiae, Moritz; Timme, Marc; Witthaut, Dirk

2015-01-01

Stable operation of complex flow and transportation networks requires balanced supply and demand. For the operation of electric power grids—due to their increasing fraction of renewable energy sources—a pressing challenge is to fit the fluctuations in decentralized supply to the distributed and temporally varying demands. To achieve this goal, common smart grid concepts suggest to collect consumer demand data, centrally evaluate them given current supply and send price information back to customers for them to decide about usage. Besides restrictions regarding cyber security, privacy protection and large required investments, it remains unclear how such central smart grid options guarantee overall stability. Here we propose a Decentral Smart Grid Control, where the price is directly linked to the local grid frequency at each customer. The grid frequency provides all necessary information about the current power balance such that it is sufficient to match supply and demand without the need for a centralized IT infrastructure. We analyze the performance and the dynamical stability of the power grid with such a control system. Our results suggest that the proposed Decentral Smart Grid Control is feasible independent of effective measurement delays, if frequencies are averaged over sufficiently large time intervals.

Privacy-Preserving Relationship Path Discovery in Social Networks

NASA Astrophysics Data System (ADS)

Mezzour, Ghita; Perrig, Adrian; Gligor, Virgil; Papadimitratos, Panos

As social networks sites continue to proliferate and are being used for an increasing variety of purposes, the privacy risks raised by the full access of social networking sites over user data become uncomfortable. A decentralized social network would help alleviate this problem, but offering the functionalities of social networking sites is a distributed manner is a challenging problem. In this paper, we provide techniques to instantiate one of the core functionalities of social networks: discovery of paths between individuals. Our algorithm preserves the privacy of relationship information, and can operate offline during the path discovery phase. We simulate our algorithm on real social network topologies.

Coordination of a supply chain with consumer return under vendor-managed consignment inventory and stochastic demand

NASA Astrophysics Data System (ADS)

Wu, Zhihui; Chen, Dongyan; Yu, Hui

2016-07-01

In this paper, the problem of the coordination policy is investigated for vendor-managed consignment inventory supply chain subject to consumer return. Here, the market demand is assumed to be affected by promotional effort and consumer return policy. The optimal consignment inventory and the optimal promotional effort level are proposed under the decentralized and centralized decisions. Based on the optimal decision conditions, the markdown allowance-promotional cost-sharing contract is investigated to coordinate the supply chain. Subsequently, the comparison between the two extreme policies shows that full-refund policy dominates the no-return policy when the returning cost and the positive effect of return policy are satisfied certain conditions. Finally, a numerical example is provided to illustrate the impacts of consumer return policy on the coordination contract and optimal profit as well as the effectiveness of the proposed supply chain decision.

Primary Health Care and tuberculosis: services evaluation.

PubMed

Wysocki, Anneliese Domingues; Ponce, Maria Amélia Zanon; Brunello, Maria Eugênia Firmino; Beraldo, Aline Ale; Vendramini, Silvia Helena Figueiredo; Scatena, Lúcia Marina; Ruffino, Antonio; Villa, Tereza Cristina Scatena

2017-01-01

In order to control tuberculosis, the Brazilian Ministry of Health recommends the decentralization of control actions directed to the Primary Health Care, and there are few studies on the performance of the Tuberculosis Control Program in decentralized contexts. To evaluate the performance of Primary Health Care services in tuberculosis treatment. This is an evaluative study with cross-sectional approach conducted in 2011. Two hundred and thirty-nine health professionals from Primary Health Care units were interviewed using a structured instrument based on the evaluation reference of the health services quality (structure - process - results). The performance of these services was analyzed applying techniques of descriptive statistics, validation, and construction of indicators and by determining the reduced variable "Z". The indicators "participation of professionals in tuberculosis patients' care" (structure) and "reference and counterreference" (process) had the best evaluations, whereas "professional training" (structure) and "external actions for tuberculosis control" (process) had the worst results. The decentralization of tuberculosis control actions has been taking place in a vertical manner in Primary Health Care. The challenge of controlling tuberculosis involves overcoming constraints related to the engagement, training, and turnover rates among health professionals, which is a coordination between services and monitoring of control actions in Primary Health Care.

Decentralized control scheme for myriapod robot inspired by adaptive and resilient centipede locomotion.

PubMed

Yasui, Kotaro; Sakai, Kazuhiko; Kano, Takeshi; Owaki, Dai; Ishiguro, Akio

2017-01-01

Recently, myriapods have attracted the attention of engineers because mobile robots that mimic them potentially have the capability of producing highly stable, adaptive, and resilient behaviors. The major challenge here is to develop a control scheme that can coordinate their numerous legs in real time, and an autonomous decentralized control could be the key to solve this problem. Therefore, we focus on real centipedes and aim to design a decentralized control scheme for myriapod robots by drawing inspiration from behavioral experiments on centipede locomotion under unusual conditions. In the behavioral experiments, we observed the response to the removal of a part of the terrain and to amputation of several legs. Further, we determined that the ground reaction force is significant for generating rhythmic leg movements; the motion of each leg is likely affected by a sensory input from its neighboring legs. Thus, we constructed a two-dimensional model wherein a simple local reflexive mechanism was implemented in each leg. We performed simulations by using this model and demonstrated that the myriapod robot could move adaptively to changes in the environment and body properties. Our findings will shed new light on designing adaptive and resilient myriapod robots that can function under various circumstances.

Effects of health decentralization, financing and governance in Mexico.

PubMed

Arredondo, Armando; Orozco, Emanuel

2006-02-01

To identify the effects of decentralization on health financing and governance policies in Mexico from the perspective of users and providers. A cross-sectional study was carried out in four states that were selected according to geopolitical and administrative criteria. Four indicators were assessed: changes and effects on governance, financing sources and funds, the final destination of resources, and fund allocation mechanisms. Data collection was performed using in-depth interviews with health system key personnel and community leaders, consensus techniques and document analyses. The interviews were transcribed and analyzed by thematic segmentation. The results show different effectiveness levels for the four states regarding changes in financing policies and community participation. Effects on health financing after decentralization were identified in each state, including: greater participation of municipal and state governments in health expenditure, increased financial participation of households, greater community participation in low-income states, duality and confusion in the new mechanisms for coordination among the three government levels, absence of an accountability system, lack of human resources and technical skills to implement, monitor and evaluate changes in financing. In general, positive and negative effects of decentralization on health financing and governance were identified. The effects mentioned by health service providers and users were related to a diversification of financing sources, a greater margin for decisions around the use and final destination of financial resources and normative development for the use of resources. At the community level, direct financial contributions were mentioned, as well as in-kind contributions, particularly in the form of community work.

USSR Report: Machine Tools and Metalworking Equipment.

DTIC Science & Technology

1986-01-23

between satellite stop and the camshaft of the programer unit. The line has 23 positions including 12 automatic ones. Specification of line Number...technological, processes, automated research, etc.) are as follows.: a monochannel based on a shared trunk line, ring, star and tree (polychannel...line or ring networks based on decentralized control of data exchange between subscribers are very robust. A tree -form network has star structure

A decentralized approach to reducing the social costs of cascading failures

NASA Astrophysics Data System (ADS)

Hines, Paul

Large cascading failures in electrical power networks come with enormous social costs. These can be direct financial costs, such as the loss of refrigerated foods in grocery stores, or more indirect social costs, such as the traffic congestion that results from the failure of traffic signals. While engineers and policy makers have made numerous technical and organizational changes to reduce the frequency and impact of large cascading failures, the existing data, as described in Chapter 2 of this work, indicate that the overall frequency and impact of large electrical blackouts in the United States are not decreasing. Motivated by the cascading failure problem, this thesis describes a new method for Distributed Model Predictive Control and a power systems application. The central goal of the method, when applied to power systems, is to reduce the social costs of cascading failures by making small, targeted reductions in load and generation and changes to generator voltage set points. Unlike some existing schemes that operate from centrally located control centers, the method is operated by software agents located at substations distributed throughout the power network. The resulting multi-agent control system is a new approach to decentralized control, combining Distributed Model Predictive Control and Reciprocal Altruism. Experimental results indicate that this scheme can in fact decrease the average size, and thus social costs, of cascading failures. Over 100 randomly generated disturbances to a model of the IEEE 300 bus test network, the method resulted in nearly an order of magnitude decrease in average event size (measured in cost) relative to cascading failure simulations without remedial control actions. Additionally, the communication requirements for the method are measured, and found to be within the bandwidth capabilities of current communications technology (on the order of 100kB/second). Experiments on several resistor networks with varying structures, including a random graph, a scale-free network and a power grid indicate that the effectiveness of decentralized control schemes, like the method proposed here, is a function of the structure of the network that is to be controlled.

Quid pro quo: a mechanism for fair collaboration in networked systems.

PubMed

Santos, Agustín; Fernández Anta, Antonio; López Fernández, Luis

2013-01-01

Collaboration may be understood as the execution of coordinated tasks (in the most general sense) by groups of users, who cooperate for achieving a common goal. Collaboration is a fundamental assumption and requirement for the correct operation of many communication systems. The main challenge when creating collaborative systems in a decentralized manner is dealing with the fact that users may behave in selfish ways, trying to obtain the benefits of the tasks but without participating in their execution. In this context, Game Theory has been instrumental to model collaborative systems and the task allocation problem, and to design mechanisms for optimal allocation of tasks. In this paper, we revise the classical assumptions of these models and propose a new approach to this problem. First, we establish a system model based on heterogenous nodes (users, players), and propose a basic distributed mechanism so that, when a new task appears, it is assigned to the most suitable node. The classical technique for compensating a node that executes a task is the use of payments (which in most networks are hard or impossible to implement). Instead, we propose a distributed mechanism for the optimal allocation of tasks without payments. We prove this mechanism to be robust evenevent in the presence of independent selfish or rationally limited players. Additionally, our model is based on very weak assumptions, which makes the proposed mechanisms susceptible to be implemented in networked systems (e.g., the Internet).

Autonomous, Decentralized Grid Architecture: Prosumer-Based Distributed Autonomous Cyber-Physical Architecture for Ultra-Reliable Green Electricity Networks

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

2012-01-11

GENI Project: Georgia Tech is developing a decentralized, autonomous, internet-like control architecture and control software system for the electric power grid. Georgia Tech’s new architecture is based on the emerging concept of electricity prosumers—economically motivated actors that can produce, consume, or store electricity. Under Georgia Tech’s architecture, all of the actors in an energy system are empowered to offer associated energy services based on their capabilities. The actors achieve their sustainability, efficiency, reliability, and economic objectives, while contributing to system-wide reliability and efficiency goals. This is in marked contrast to the current one-way, centralized control paradigm.

A cooperative game theory approach to transmission planning in power systems

NASA Astrophysics Data System (ADS)

Contreras, Javier

The rapid restructuring of the electric power industry from a vertically integrated entity into a decentralized industry has given rise to complex problems. In particular, the transmission component of the electric power system requires new methodologies to fully capture this emerging competitive industry. Game theory models are used to model strategic interactions in a competitive environment. This thesis presents a new decentralized framework to study the transmission network expansion problem using cooperative game theory. First, the players and the rules of the game are defined. Second, a coalition formation scheme is developed. Finally, the optimized cost of expansion is allocated based on the history of the coalition formation.

Gemini: Extending Information Management for Real Time Tactical Environments

DTIC Science & Technology

2008-03-01

Mobile,  Ad ‐ Hoc  Networks.......................................................................................................49  8.4  Wired...networks, such as  wireless  ad ‐ hoc  networks. This paper looked into the operating environments expected to be available to  Unmanned Aircraft Systems...decentralized,  ad ‐ hoc   networks. The total peering capability of these networks may be very large. And, each network or access  point may carry restrictions; for

Simulating the decentralized processes of the human immune system in a virtual anatomy model.

PubMed

Sarpe, Vladimir; Jacob, Christian

2013-01-01

Many physiological processes within the human body can be perceived and modeled as large systems of interacting particles or swarming agents. The complex processes of the human immune system prove to be challenging to capture and illustrate without proper reference to the spatial distribution of immune-related organs and systems. Our work focuses on physical aspects of immune system processes, which we implement through swarms of agents. This is our first prototype for integrating different immune processes into one comprehensive virtual physiology simulation. Using agent-based methodology and a 3-dimensional modeling and visualization environment (LINDSAY Composer), we present an agent-based simulation of the decentralized processes in the human immune system. The agents in our model - such as immune cells, viruses and cytokines - interact through simulated physics in two different, compartmentalized and decentralized 3-dimensional environments namely, (1) within the tissue and (2) inside a lymph node. While the two environments are separated and perform their computations asynchronously, an abstract form of communication is allowed in order to replicate the exchange, transportation and interaction of immune system agents between these sites. The distribution of simulated processes, that can communicate across multiple, local CPUs or through a network of machines, provides a starting point to build decentralized systems that replicate larger-scale processes within the human body, thus creating integrated simulations with other physiological systems, such as the circulatory, endocrine, or nervous system. Ultimately, this system integration across scales is our goal for the LINDSAY Virtual Human project. Our current immune system simulations extend our previous work on agent-based simulations by introducing advanced visualizations within the context of a virtual human anatomy model. We also demonstrate how to distribute a collection of connected simulations over a network of computers. As a future endeavour, we plan to use parameter tuning techniques on our model to further enhance its biological credibility. We consider these in silico experiments and their associated modeling and optimization techniques as essential components in further enhancing our capabilities of simulating a whole-body, decentralized immune system, to be used both for medical education and research as well as for virtual studies in immunoinformatics.

Growing trees in child brains: graph theoretical analysis of electroencephalography-derived minimum spanning tree in 5- and 7-year-old children reflects brain maturation.

PubMed

Boersma, Maria; Smit, Dirk J A; Boomsma, Dorret I; De Geus, Eco J C; Delemarre-van de Waal, Henriette A; Stam, Cornelis J

2013-01-01

The child brain is a small-world network, which is hypothesized to change toward more ordered configurations with development. In graph theoretical studies, comparing network topologies under different conditions remains a critical point. Constructing a minimum spanning tree (MST) might present a solution, since it does not require setting a threshold and uses a fixed number of nodes and edges. In this study, the MST method is introduced to examine developmental changes in functional brain network topology in young children. Resting-state electroencephalography was recorded from 227 children twice at 5 and 7 years of age. Synchronization likelihood (SL) weighted matrices were calculated in three different frequency bands from which MSTs were constructed, which represent constructs of the most important routes for information flow in a network. From these trees, several parameters were calculated to characterize developmental change in network organization. The MST diameter and eccentricity significantly increased, while the leaf number and hierarchy significantly decreased in the alpha band with development. Boys showed significant higher leaf number, betweenness, degree and hierarchy and significant lower SL, diameter, and eccentricity than girls in the theta band. The developmental changes indicate a shift toward more decentralized line-like trees, which supports the previously hypothesized increase toward regularity of brain networks with development. Additionally, girls showed more line-like decentralized configurations, which is consistent with the view that girls are ahead of boys in brain development. MST provides an elegant method sensitive to capture subtle developmental changes in network organization without the bias of network comparison.

Homophyly/kinship hypothesis: Natural communities, and predicting in networks

NASA Astrophysics Data System (ADS)

Li, Angsheng; Li, Jiankou; Pan, Yicheng

2015-02-01

It has been a longstanding challenge to understand natural communities in real world networks. We proposed a community finding algorithm based on fitness of networks, two algorithms for prediction, accurate prediction and confirmation of keywords for papers in the citation network Arxiv HEP-TH (high energy physics theory), and the measures of internal centrality, external de-centrality, internal and external slopes to characterize the structures of communities. We implemented our algorithms on 2 citation and 5 cooperation graphs. Our experiments explored and validated a homophyly/kinship principle of real world networks. The homophyly/kinship principle includes: (1) homophyly is the natural selection in real world networks, similar to Darwin's kinship selection in nature, (2) real world networks consist of natural communities generated by the natural selection of homophyly, (3) most individuals in a natural community share a short list of common attributes, (4) natural communities have an internal centrality (or internal heterogeneity) that a natural community has a few nodes dominating most of the individuals in the community, (5) natural communities have an external de-centrality (or external homogeneity) that external links of a natural community homogeneously distributed in different communities, and (6) natural communities of a given network have typical structures determined by the internal slopes, and have typical patterns of outgoing links determined by external slopes, etc. Our homophyly/kinship principle perfectly matches Darwin's observation that animals from ants to people form social groups in which most individuals work for the common good, and that kinship could encourage altruistic behavior. Our homophyly/kinship principle is the network version of Darwinian theory, and builds a bridge between Darwinian evolution and network science.

Adaptive Probabilistic Protocols for Advanced Networks/Assuring the Integrity of Highly Decentralized Communications Systems

DTIC Science & Technology

2005-03-01

to obtain a protocol customized to the needs of a specific setting, under control of an automated theorem proving system that can guarantee...new “compositional” method for protocol design and implementation, in which small microprotocols are combined to obtain a protocol customized to the...and Network Centric Enterprise (NCES) visions. This final report documents a wide range of contributions and technology transitions, including: A

Advanced Decentralized Water/Energy Network Design for Sustainable Infrastructure

EPA Science Inventory

In order to provide a water infrastructure that is more sustainable into and beyond the 21st century, drinking water distribution systems and wastewater collection systems must account for our diminishing water supply, increasing demands, climate change, energy cost and availabil...

A QoS Management Technique of Urgent Information Provision in ITS Services Using DSRC for Autonomous Base Stations

NASA Astrophysics Data System (ADS)

Shimura, Akitoshi; Aizono, Takeiki; Hiraiwa, Masashi; Sugano, Shigeki

A QoS management technique based on an autonomous decentralized mobility system, which is an autonomous decentralized system enhanced to provide mobile stations with information about urgent roadway situations, is proposed in this paper. This technique enables urgent messages to be flexibly and quickly transmitted to mobile stations by multiple decentralized base stations using dedicated short range communication. It also supports the easy addition of additional base stations. Each station autonomously creates information-delivery communities based on the urgency of the messages it receives through the roadside network and the distances between the senders and receivers. Each station dynamically determines the urgency of messages according to the message content and the speed of the mobile stations. Evaluation of this technique applied to the Smart Gateway system, which provides driving-assistance services to mobile stations through dedicated short-range communication, demonstrated its effectiveness and that it is suitable for actual systems.

Fuzzy bilevel programming with multiple non-cooperative followers: model, algorithm and application

NASA Astrophysics Data System (ADS)

Ke, Hua; Huang, Hu; Ralescu, Dan A.; Wang, Lei

2016-04-01

In centralized decision problems, it is not complicated for decision-makers to make modelling technique selections under uncertainty. When a decentralized decision problem is considered, however, choosing appropriate models is no longer easy due to the difficulty in estimating the other decision-makers' inconclusive decision criteria. These decision criteria may vary with different decision-makers because of their special risk tolerances and management requirements. Considering the general differences among the decision-makers in decentralized systems, we propose a general framework of fuzzy bilevel programming including hybrid models (integrated with different modelling methods in different levels). Specially, we discuss two of these models which may have wide applications in many fields. Furthermore, we apply the proposed two models to formulate a pricing decision problem in a decentralized supply chain with fuzzy coefficients. In order to solve these models, a hybrid intelligent algorithm integrating fuzzy simulation, neural network and particle swarm optimization based on penalty function approach is designed. Some suggestions on the applications of these models are also presented.

Collision-free motion planning for fiber positioner robots: discretization of velocity profiles

NASA Astrophysics Data System (ADS)

Makarem, Laleh; Kneib, Jean-Paul; Gillet, Denis; Bleuler, Hannes; Bouri, Mohamed; Hörler, Philippe; Jenni, Laurent; Prada, Francisco; Sánchez, Justo

2014-07-01

The next generation of large-scale spectroscopic survey experiments such as DESI, will use thousands of fiber positioner robots packed on a focal plate. In order to maximize the observing time with this robotic system we need to move in parallel the fiber-ends of all positioners from the previous to the next target coordinates. Direct trajectories are not feasible due to collision risks that could undeniably damage the robots and impact the survey operation and performance. We have previously developed a motion planning method based on a novel decentralized navigation function for collision-free coordination of fiber positioners. The navigation function takes into account the configuration of positioners as well as their envelope constraints. The motion planning scheme has linear complexity and short motion duration (2.5 seconds with the maximum speed of 30 rpm for the positioner), which is independent of the number of positioners. These two key advantages of the decentralization designate the method as a promising solution for the collision-free motion-planning problem in the next-generation of fiber-fed spectrographs. In a framework where a centralized computer communicates with the positioner robots, communication overhead can be reduced significantly by using velocity profiles consisting of a few bits only. We present here the discretization of velocity profiles to ensure the feasibility of a real-time coordination for a large number of positioners. The modified motion planning method that generates piecewise linearized position profiles guarantees collision-free trajectories for all the robots. The velocity profiles fit few bits at the expense of higher computational costs.

Analysis of Decentralized Variable Structure Control for Collective Search by Mobile Robots

DOE Office of Scientific and Technical Information (OSTI.GOV)

Feddema, J.; Goldsmith, S.; Robinett, R.

1998-11-04

This paper presents an analysis of a decentralized coordination strategy for organizing and controlling a team of mobile robots performing collective search. The alpha-beta coordination strategy is a family of collective search algorithms that allow teams of communicating robots to implicitly coordinate their search activities through a division of labor based on self-selected roIes. In an alpha-beta team. alpha agents are motivated to improve their status by exploring new regions of the search space. Beta a~ents are conservative, and reiy on the alpha agents to provide advanced information on favorable regions of the search space. An agent selects its currentmore » role dynamically based on its current status value relative to the current status values of the other team members. Status is determined by some function of the agent's sensor readings, and is generally a measurement of source intensity at the agent's current location. Variations on the decision rules determining alpha and beta behavior produce different versions of the algorithm that lead to different global properties. The alpha-beta strategy is based on a simple finite-state machine that implements a form of Variable Structure Control (VSC). The VSC system changes the dynamics of the collective system by abruptly switching at defined states to alternative control laws . In VSC, Lyapunov's direct method is often used to design control surfaces which guide the system to a given goal. We introduce the alpha-beta aIgorithm and present an analysis of the equilibrium point and the global stability of the alpha-beta algorithm based on Lyapunov's method.« less

Analysis of decentralized variable structure control for collective search by mobile robots

NASA Astrophysics Data System (ADS)

Goldsmith, Steven Y.; Feddema, John T.; Robinett, Rush D., III

1998-10-01

This paper presents an analysis of a decentralized coordination strategy for organizing and controlling a team of mobile robots performing collective search. The alpha- beta coordination strategy is a family of collective search algorithms that allow teams of communicating robots to implicitly coordinate their search activities through a division of labor based on self-selected roles. In an alpha- beta team, alpha agents are motivated to improve their status by exploring new regions of the search space. Beta agents are conservative, and rely on the alpha agents to provide advanced information on favorable regions of the search space. An agent selects its current role dynamically based on its current status value relative to the current status values of the other team members. Status is determined by some function of the agent's sensor readings, and is generally a measurement of source intensity at the agent's current location. Variations on the decision rules determining alpha and beta behavior produce different versions of the algorithm that lead to different global properties. The alpha-beta strategy is based on a simple finite-state machine that implements a form of Variable Structure Control (VSC). The VSC system changes the dynamics of the collective system by abruptly switching at defined states to alternative control laws. In VSC, Lyapunov's direct method is often used to design control surfaces which guide the system to a given goal. We introduce the alpha- beta algorithm and present an analysis of the equilibrium point and the global stability of the alpha-beta algorithm based on Lyapunov's method.

[Supporting the intermediate level of health care in urban health areas in Kinshasa (1995-2005), DR Congo].

PubMed

Mbeva, Jean-Bosco Kahindo; Schirvel, Carole; Karemere, Hermès; Porignon, Denis

2012-06-08

As a result of the decentralization of health systems, some countries have introduced intermediate (provincial) levels in their public health system. This paper presents the results of a case study conducted in Kinshasa on health system decentralization. The study identified a shift from a focus on regulation compliance assessment to an emphasis on health system coordination and health district support. It also highlighted the emergence of a?managerial (as opposed to a bureaucratic) approach to health district support. The performance of health districts in terms of health care coverage and health service use were also found to have improved. The results highlight the importance of intermediate levels in?the health care system and the value of a more organic and managerial rationality in supporting health districts faced with the complexity of urban environments and the integration of specialized multi-partner programs and interventions.

A Framework for Information Theoretic Cooperative Sensing and Predictive Control

DTIC Science & Technology

2012-09-11

Miroslav Barić and Francesco Borelli , Decentralized Robust Control Invariance for a Network of Integrators, Proceeding of American Control...from http: //www.mpc.berkeley.edu. P4 Miroslav Barić and Francesco Borelli , Distributed Averaging with Flow Constraints, Proceeding of American Control

Adaptive Neural Networks Prescribed Performance Control Design for Switched Interconnected Uncertain Nonlinear Systems.

PubMed

Li, Yongming; Tong, Shaocheng

2017-06-28

In this paper, an adaptive neural networks (NNs)-based decentralized control scheme with the prescribed performance is proposed for uncertain switched nonstrict-feedback interconnected nonlinear systems. It is assumed that nonlinear interconnected terms and nonlinear functions of the concerned systems are unknown, and also the switching signals are unknown and arbitrary. A linear state estimator is constructed to solve the problem of unmeasured states. The NNs are employed to approximate unknown interconnected terms and nonlinear functions. A new output feedback decentralized control scheme is developed by using the adaptive backstepping design technique. The control design problem of nonlinear interconnected switched systems with unknown switching signals can be solved by the proposed scheme, and only a tuning parameter is needed for each subsystem. The proposed scheme can ensure that all variables of the control systems are semi-globally uniformly ultimately bounded and the tracking errors converge to a small residual set with the prescribed performance bound. The effectiveness of the proposed control approach is verified by some simulation results.

Using a Novel Wireless-Networked Decentralized Control Scheme under Unpredictable Environmental Conditions

PubMed Central

Chang, Chung-Liang; Huang, Yi-Ming; Hong, Guo-Fong

2015-01-01

The direction of sunshine or the installation sites of environmental control facilities in the greenhouse result in different temperature and humidity levels in the various zones of the greenhouse, and thus, the production quality of crop is inconsistent. This study proposed a wireless-networked decentralized fuzzy control scheme to regulate the environmental parameters of various culture zones within a greenhouse. The proposed scheme can create different environmental conditions for cultivating different crops in various zones and achieve diversification or standardization of crop production. A star-type wireless sensor network is utilized to communicate with each sensing node, actuator node, and control node in various zones within the greenhouse. The fuzzy rule-based inference system is used to regulate the environmental parameters for temperature and humidity based on real-time data of plant growth response provided by a growth stage selector. The growth stage selector defines the control ranges of temperature and humidity of the various culture zones according to the leaf area of the plant, the number of leaves, and the cumulative amount of light. The experimental results show that the proposed scheme is stable and robust and provides basis for future greenhouse applications. PMID:26569264

[Direccion General de Comunicacion. Programa Nacional de Comunicacion en Poblacion].

PubMed

1988-06-01

Peru's National Population Council is currently developing a national program of population communication. The program will be coordinated with public and private sector activities and will seek help from international organizations. The objective of the program is to promote changes in population knowledge, attitudes, and behaviors in priority social sectors and general public opinion to achieve a better harmony between population growth and distribution and socioeconomic development. The program strategy is to begin with identification of priority audiences. Other components of the strategy include quality control, coordination, decentralization, participation, use of low-cost technologies with high impact, and a multidisciplinary focus. An inventory of institutional activities in population communication will be a major activity.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Yue J.; Malikopoulos, Andreas; Cassandras, Christos G.

We address the problem of coordinating online a continuous flow of connected and automated vehicles (CAVs) crossing two adjacent intersections in an urban area. We present a decentralized optimal control framework whose solution yields for each vehicle the optimal acceleration/deceleration at any time in the sense of minimizing fuel consumption. The solu- tion, when it exists, allows the vehicles to cross the intersections without the use of traffic lights, without creating congestion on the connecting road, and under the hard safety constraint of collision avoidance. The effectiveness of the proposed solution is validated through simulation considering two intersections located inmore » downtown Boston, and it is shown that coordination of CAVs can reduce significantly both fuel consumption and travel time.« less

Entanglement-Gradient Routing for Quantum Networks.

PubMed

Gyongyosi, Laszlo; Imre, Sandor

2017-10-27

We define the entanglement-gradient routing scheme for quantum repeater networks. The routing framework fuses the fundamentals of swarm intelligence and quantum Shannon theory. Swarm intelligence provides nature-inspired solutions for problem solving. Motivated by models of social insect behavior, the routing is performed using parallel threads to determine the shortest path via the entanglement gradient coefficient, which describes the feasibility of the entangled links and paths of the network. The routing metrics are derived from the characteristics of entanglement transmission and relevant measures of entanglement distribution in quantum networks. The method allows a moderate complexity decentralized routing in quantum repeater networks. The results can be applied in experimental quantum networking, future quantum Internet, and long-distance quantum communications.

An experimental paradigm for team decision processes

NASA Technical Reports Server (NTRS)

Serfaty, D.; Kleinman, D. L.

1986-01-01

The study of distributed information processing and decision making is presently hampered by two factors: (1) The inherent complexity of the mathematical formulation of decentralized problems has prevented the development of models that could be used to predict performance in a distributed environment; and (2) The lack of comprehensive scientific empirical data on human team decision making has hindered the development of significant descriptive models. As a part of a comprehensive effort to find a new framework for multihuman decision making problems, a novel experimental research paradigm was developed involving human terms in decision making tasks. Attempts to construct parts of an integrated model with ideas from queueing networks, team theory, distributed estimation and decentralized resource management are described.

Continued implementation and testing of a Neighborhood Office Center (NOC) and integration of the NOC with an administrative correspondence management information system

NASA Technical Reports Server (NTRS)

1978-01-01

The concept of decentralized (remote) neighborhood offices, linked together through a self-sustaining communications network for exchanging voice messages, video images, and digital data was quantitatively evaluated. Hardware and procedures for the integrated multifunctional system were developed. The configuration of the neighborhood office center (NOC) is explained, its production statistics given, and an experiment for NOC network integration via satellite is described. The hardware selected for the integration NOC/management information system is discussed, and the NASA teleconferencing network is evaluated.

[Food and nutritional security: situation analysis of decentralization in the national public policy].

PubMed

Vasconcellos, Ana Beatriz Pinto de Almeida; Moura, Leides Barroso Azevedo de

2018-03-01

The aim of this study was to analyze the situation with the decentralization of the Brazilian National System of Food and Nutritional Security (SISAN), created in 2006 under the Brazilian National Food and Nutritional Security Act (LOSAN). Based on the criteria for joining SISAN, as set out in Decree 7,272 of August 25, 2010, the authors analyzed data from the basic information surveys of the Brazilian Institute of Geography and Statistics, 2014 (Estadic e Munic/2014). The results show that decentralization of SISAN is still incipient at the municipal level, although all the states of Brazil have already joined the system. The social assistance sector has played an outstanding role in coordinating SISAN at the state and municipal levels, while in the latter the health sector has also played a relevant role. The analysis of food and nutritional security activities conducted to date, based on the sources of federal, state, and municipal funds, further shows that the federal sphere has still not played a strong inductive role capable of leading the expansion of SISAN. More effective funding mechanisms and the assignment of responsibilities to the states and municipalities are relevant factors for consolidating the system's state-level base and expanding the municipal base in the search for an identity and capillarity for SISAN.

The Use of Decentralized Control in the Design of a Large Segmented Space Reflector

NASA Technical Reports Server (NTRS)

Ryaciotaki-Boussalis, Helen; Mirmirani, Maj; Rad, Khosrow; Morales, Mauricio; Velazquez, Efrain; Chassiakos, Anastasios; Luzardo, Jose-Alberto

1997-01-01

The 3-dimensional model for a segmented reflector telescope is developed using finite element techniques. The structure is decomposed into six subsystems. System control design using neural networks is performed. Performance evaluation is demonstrated via simulation using PRO-MATLAB and SIMULINK.

Library Legislation as a Research Subject.

ERIC Educational Resources Information Center

Kolodziejska, Jadwiga

Polish library legislation enacted since World War II is directed to the establishment of a library network, centralized in concepts and goals, but decentralized in administration and operation. Dating from 1774 when the Commission for National Education first issued regulations for schools and libraries, there has been continuous legislative…

Change of strategy is required for malaria elimination: a case study in Purworejo District, Central Java Province, Indonesia.

PubMed

Murhandarwati, E Elsa Herdiana; Fuad, Anis; Sulistyawati; Wijayanti, Mahardika Agus; Bia, Michael Badi; Widartono, Barandi Sapta; Kuswantoro; Lobo, Neil F; Supargiyono; Hawley, William A

2015-08-16

Malaria has been targeted for elimination from Indonesia by 2030, with varying timelines for specific geographical areas based on disease endemicity. The regional deadline for malaria elimination for Java island, given the steady decrease of malaria cases, was the end of 2015. Purworejo District, a malaria-endemic area in Java with an annual parasite incidence (API) of 0.05 per 1,000 population in 2009, aims to enter this elimination stage. This study documents factors that affect incidence and spatial distribution of malaria in Purworejo, such as geomorphology, topography, health system issues, and identifies potential constraints and challenges to achieve the elimination stage, such as inter-districts coordination, decentralization policy and allocation of financial resources for the programme. Historical malaria data from 2007 to 2011 were collected through secondary data, in-depth interviews and focus group discussions during study year (2010-2011). Malaria cases were mapped using the village-centroid shape file to visualize its distribution with geomorphologic characteristics overlay and spatial distribution of malaria. API in each village in Purworejo and its surrounding districts from 2007 to 2011 was stratified into high, middle or low case incidence to show the spatiotemporal mapping pattern. The spatiotemporal pattern of malaria cases in Purworejo and the adjacent districts demonstrate repeated concentrated occurrences of malaria in specific areas from 2007 to 2011. District health system issues, i.e., suboptimal coordination between primary care and referral systems, suboptimal inter-district collaboration for malaria surveillance, decentralization policy and the lack of resources, especially district budget allocations for the malaria programme, were major constraints for programme sustainability. A new malaria elimination approach that fits the local disease transmission, intervention and political system is required. These changes include timely measurements of malaria transmission, revision of the decentralized government system and optimizing the use of the district capitation fund followed by an effective technical implementation of the intervention strategy.

Stroke Thrombolysis in a Centralized and a Decentralized System (Helsinki and Telemedical Project for Integrative Stroke Care Network).

PubMed

Hubert, Gordian J; Meretoja, Atte; Audebert, Heinrich J; Tatlisumak, Turgut; Zeman, Florian; Boy, Sandra; Haberl, Roman L; Kaste, Markku; Müller-Barna, Peter

2016-12-01

Intravenous thrombolysis with tissue-type plasminogen activator (tPA) for acute ischemic stroke is more effective when delivered early. Timely delivery is challenging particularly in rural areas with long distances. We compared delays and treatment rates of a large, decentralized telemedicine-based system and a well-organized, large, centralized single-hospital system. We analyzed the centralized system of the Helsinki University Central Hospital (Helsinki and Province of Uusimaa, Finland, 1.56 million inhabitants, 9096 km 2 ) and the decentralized TeleStroke Unit network in a predominantly rural area (Telemedical Project for Integrative Stroke Care [TEMPiS], South-East Bavaria, Germany, 1.94 million inhabitants, 14 992 km 2 ). All consecutive tPA treatments were prospectively registered. We compared tPA rates per total ischemic stroke admissions in the Helsinki and TEMPiS catchment areas. For delay comparisons, we excluded patients with basilar artery occlusions, in-hospital strokes, and those being treated after 270 minutes. From January 1, 2011, to December 31, 2013, 912 patients received tPA in Helsinki University Central Hospital and 1779 in TEMPiS hospitals. Area-based tPA rates were equal (13.0% of 7017 ischemic strokes in the Helsinki University Central Hospital area versus 13.3% of 14 637 ischemic strokes in the TEMPiS area; P=0.078). Median prehospital delays were longer (88; interquartile range, 60-135 versus 65; 48-101 minutes; P<0.001) but in-hospital delays were shorter (18; interquartile range, 13-30 versus 39; 26-56 minutes; P<0.001) in Helsinki University Central Hospital compared with TEMPiS with no difference in overall delays (117; interquartile range, 81-168 versus 115; 87-155 minutes; P=0.45). A decentralized telestroke thrombolysis service can achieve similar treatment rates and time delays for a rural population as a centralized system can achieve for an urban population. © 2016 American Heart Association, Inc.

[Community mental health networks and doors at a Health and Community Center (CeSAC No 24) in the south of the Autonomous City of Buenos Aires (CABA)].

PubMed

Corin, Marcela

2013-01-01

The history of the Health and Community Center (CeSAC) No 24 began 21 years ago in the Ramón Carrillo district, in Villa Soldati neighborhood. This is a marginal urban area in the south of the CABA with a population with urgent needs. The work started with a group of professionals dealing with primary care practices, and it continues up to the present. The goal of our community mental health project is the creation of spaces for prevention and well-being including art in all its expressions, with the active participation of neighbors in the coordination of many activities. Through the symbolic opening of doors and making networks visible, we opened the CeSAC to universities, scientific societies, foundations, NGOs, neighbor committees, neighborhood boards, human rights organizations, formal and informal education centers, cultural centers, churches, community radios, in order to show the vital movements of the community, as we -as a team- are an integral part of it. Our spaces, workshops and programs are a collective socio-historical construction that achieves milestones such as thinking, thinking of us, getting together and achieving the participation from the community and the continuous training for everybody working and living in Soldati. The decentralization and democratization trend, and the heterarchical management of our organization favors the possibility of catalyzing the wishes, motivations and efforts of the healthcare team, neighbors and network nodes, thus benefiting the creative work that turns a dream into a hopeful reality.

Efficient Multi-Source Data Fusion for Decentralized Sensor Networks

DTIC Science & Technology

2006-10-01

Operating Picture (COP). Robovolc, accessing a single DDF node associated with a CCTV camera (marked in orange in Figure 3a), defends a ‘ sensitive ...Gaussian environments. Figure 10: Particle Distribution Snapshots osition error between each target and the me ed particle set at the bearing-only

The Rise of Networks: How Decentralized Management Is Improving Schools

ERIC Educational Resources Information Center

Kelleher, Maureen

2014-01-01

School districts across the country are shifting away from their traditional management paradigm--a central office that directs its schools through uniform mandates and policies--toward a new vision where district leaders support autonomous schools while holding them accountable for student performance. The advent of new governance mechanisms…

Circulating Power and In/Visibility: Layers of Educational Leadership

ERIC Educational Resources Information Center

Mifsud, Denise

2015-01-01

Purpose: The purpose of this paper is to study circulating power and in/visibility. In the unfolding Maltese education scenario of decentralization and school networking, suffused with entrenched power, with added layers of leadership and more subtle levels of accountability, this paper explores the underlying power relations among the top…

40 CFR 51.353 - Network type and program evaluation.

Code of Federal Regulations, 2010 CFR

2010-07-01

... § 51.351 or 51.352 of this subpart. For decentralized programs other than those meeting the design... presumptively equivalent to a centralized, test-only system including comparable test elements. States may allow...-serve gasoline, pre-packaged oil, or other, non-automotive, convenience store items. At the State's...

40 CFR 51.353 - Network type and program evaluation.

Code of Federal Regulations, 2012 CFR

2012-07-01

... § 51.351 or 51.352 of this subpart. For decentralized programs other than those meeting the design... presumptively equivalent to a centralized, test-only system including comparable test elements. States may allow...-serve gasoline, pre-packaged oil, or other, non-automotive, convenience store items. At the State's...

40 CFR 51.353 - Network type and program evaluation.

Code of Federal Regulations, 2014 CFR

2014-07-01

... § 51.351 or 51.352 of this subpart. For decentralized programs other than those meeting the design... presumptively equivalent to a centralized, test-only system including comparable test elements. States may allow...-serve gasoline, pre-packaged oil, or other, non-automotive, convenience store items. At the State's...

Catching the ’Network Science’ Bug: Insight and Opportunity for the Operations Researcher

DTIC Science & Technology

2008-01-21

publication: Operations Research agents often interface in a decentralized and asynchronous manner, and where the interaction of “ selfish ” agents...interaction of the two. For example, in a metabolic network, the activation of a gene may alter the biochemical pathways that in turn can alter other genes , and...people, computers, vehicles, cells, or genes . In these systems, all configurations are not feasible, simply because survival for these systems means

Western State Hospital: implementing a MUMPS-based PC network.

PubMed

Russ, D C

1991-06-01

Western State Hospital, a state-administered 1,200-bed mental health institution near Tacoma, Wash., confronted the challenge of automating its large campus through the application of the Healthcare Integrated Information System (HIIS). It is the first adaptation of the Veterans Administration's Decentralized Hospital Computer Program software in a mental health institution of this size, and the first DHCP application to be installed on a PC client/server network in a large U.S. hospital.

A flooding algorithm for multirobot exploration.

PubMed

Cabrera-Mora, Flavio; Xiao, Jizhong

2012-06-01

In this paper, we present a multirobot exploration algorithm that aims at reducing the exploration time and to minimize the overall traverse distance of the robots by coordinating the movement of the robots performing the exploration. Modeling the environment as a tree, we consider a coordination model that restricts the number of robots allowed to traverse an edge and to enter a vertex during each step. This coordination is achieved in a decentralized manner by the robots using a set of active landmarks that are dropped by them at explored vertices. We mathematically analyze the algorithm on trees, obtaining its main properties and specifying its bounds on the exploration time. We also define three metrics of performance for multirobot algorithms. We simulate and compare the performance of this new algorithm with those of our multirobot depth first search (MR-DFS) approach presented in our recent paper and classic single-robot DFS.

Shared Activity Coordination

NASA Technical Reports Server (NTRS)

Clement, Bradley J.; Barrett, Anthony C.

2003-01-01

Interacting agents that interleave planning and execution must reach consensus on their commitments to each other. In domains where agents have varying degrees of interaction and different constraints on communication and computation, agents will require different coordination protocols in order to efficiently reach consensus in real time. We briefly describe a largely unexplored class of real-time, distributed planning problems (inspired by interacting spacecraft missions), new challenges they pose, and a general approach to solving the problems. These problems involve self-interested agents that have infrequent communication but collaborate on joint activities. We describe a Shared Activity Coordination (SHAC) framework that provides a decentralized algorithm for negotiating the scheduling of shared activities in a dynamic environment, a soft, real-time approach to reaching consensus during execution with limited communication, and a foundation for customizing protocols for negotiating planner interactions. We apply SHAC to a realistic simulation of interacting Mars missions and illustrate the simplicity of protocol development.

Continual coordination through shared activities

NASA Technical Reports Server (NTRS)

Clement, Bradley J.; Barrett, Anthony C.

2003-01-01

Interacting agents that interleave planning and execution must reach consensus on their commitments to each other. In domains where agents have varying degrees of interaction and different constraints on communication and computation, agents will require different coordination protocols in order to efficiently reach consensus in real time. We briefly describe a largely unexplored class of realtime, distributed planning problems (inspired by interacting spacecraft missions), new challenges they pose, and a general approach to solving the problems. These problems involve self-interested agents that have infrequent communication but collaborate on joint activities. We describe a Shared Activity Coordination (SHAC) framework that provides a decentralized algorithm for negotiating the scheduling of shared activities over the lifetimes of separate missions, a soft, real-time approach to reaching consensus during execution with limited communication, and a foundation for customizing protocols for negotiating planner interactions. We apply SHAC to a realistic simulation of interacting Mars missions and illustrate the simplicity of protocol development.

Argumentation for coordinating shared activities

NASA Technical Reports Server (NTRS)

Clement, Bradley J.; Barrett, Anthony C.; Schaffer, Steven R.

2004-01-01

an increasing need for space missions to be able to collaboratively (and competitively) develop plans both within and across missions. In addition, interacting spacecraft that interleave onboard planning and execution must reach consensus on their commitments to each other prior to execution. In domains where missions have varying degrees of interaction and different constraints on communication and computation, the missions will require different coordination protocols in order to efficiently reach consensus with in their imposed deadlines. We describe a Shared Activity Coordination (SHAC) framework that provides a decentralized algorithm for negotiating the scheduling of shared activities over the lifetimes of multiple agents and a foundation for customizing protocols for negotiating planner interactions. We investigate variations of a few simple protocols based on argumentation and distributed constraints satisfaction techniques and evaluate their abilities to reach consistent solutions according to computation, time, and communication costs in an abstract domain where spacecraft propose joint measurements.

Impacts on the Voltage Profile of DC Distribution Network with DG Access

NASA Astrophysics Data System (ADS)

Tu, J. J.; Yin, Z. D.

2017-07-01

With the development of electronic, more and more distributed generations (DGs) access into grid and cause the research fever of direct current (DC) distribution network. Considering distributed generation (DG) location and capacity have great impacts on voltage profile, so use IEEE9 and IEEE33 typical circuit as examples, with DGs access in centralized and decentralized mode, to compare voltage profile in alternating and direct current (AC/DC) distribution network. Introducing the voltage change ratio as an evaluation index, so gets the general results on voltage profile of DC distributed network with DG access. Simulation shows that, in the premise of reasonable location and capacity, DC distribution network is more suitable for DG access.

Quality of Service Metrics in Wireless Sensor Networks: A Survey

NASA Astrophysics Data System (ADS)

Snigdh, Itu; Gupta, Nisha

2016-03-01

Wireless ad hoc network is characterized by autonomous nodes communicating with each other by forming a multi hop radio network and maintaining connectivity in a decentralized manner. This paper presents a systematic approach to the interdependencies and the analogy of the various factors that affect and constrain the wireless sensor network. This article elaborates the quality of service parameters in terms of methods of deployment, coverage and connectivity which affect the lifetime of the network that have been addressed, till date by the different literatures. The analogy of the indispensable rudiments was discussed that are important factors to determine the varied quality of service achieved, yet have not been duly focused upon.

Transition from isotropic to digitated growth modulates network formation in Physarum polycephalum

NASA Astrophysics Data System (ADS)

Vogel, David; Gautrais, Jacques; Perna, Andrea; Sumpter, David J. T.; Deneubourg, Jean-Louis; Dussutour, Audrey

2017-01-01

Some organisms, including fungi, ants, and slime molds, explore their environment and forage by forming interconnected networks. The plasmodium of the slime mold Physarum polycephalum is a large unicellular amoeboid organism that grows a tubular spatial network through which nutrients, body mass, and chemical signals are transported. Individual plasmodia are capable of sophisticated behaviours such as optimizing their network connectivity and dynamics using only decentralized information processing. In this study, we used a population of plasmodia that interconnect through time to analyse the dynamical interactions between growth of individual plasmodia and global network formation. Our results showed how initial conditions, such as the distance between plasmodia, their size, or the presence and quality of food, affect the emerging network connectivity.

A balance of bottom-up and top-down in linking climate policies

NASA Astrophysics Data System (ADS)

Green, Jessica F.; Sterner, Thomas; Wagner, Gernot

2014-12-01

Top-down climate negotiations embodied by the Kyoto Protocol have all but stalled, chiefly because of disagreements over targets and objections to financial transfers. To avoid those problems, many have shifted their focus to linkage of bottom-up climate policies such as regional carbon markets. This approach is appealing, but we identify four obstacles to successful linkage: different levels of ambition; competing domestic policy objectives; objections to financial transfers; and the difficulty of close regulatory coordination. Even with a more decentralized approach, overcoming the 'global warming gridlock' of the intergovernmental negotiations will require close international coordination. We demonstrate how a balance of bottom-up and top-down elements can create a path toward an effective global climate architecture.

Linking: Today's Libraries, Tomorrow's Technologies. Report of the Bibliographic and Communications Network Pilot Project. Canadian Network Papers Number 7 = Le Lien entre les Bibliotheques d'Aujourd'hui et les Technologies de Demain. Rapport du Projet Pilote du Reseau de Services Bibliographiques et de Communications. Documents sur les Reseaux Canadiens Numero 7.

ERIC Educational Resources Information Center

National Library of Canada, Ottawa (Ontario).

A pilot project was conducted from May 1980 to November 1983 to test the application of iNet--a decentralized, packet-switched telecommunications network--to bibliographic data interchange in Canada. The principal components of the project were participation of the Bibliographic Common Interest Group (BCIP), a group of libraries with stand-alone,…

A Streaming Content Distribution Network for E-Learning Support

ERIC Educational Resources Information Center

Esteve, M.; Molina, B.; Palau, C.; Fortino, G.

2006-01-01

To date e-Learning material has usually been accessed and delivered through a central web server. As the number of users, the amount of information, the frequency of accesses and the volume of data increase, together with the introduction of multimedia streaming applications, a decentralized content distribution architecture is necessary. In this…

Scalability of Findability: Decentralized Search and Retrieval in Large Information Networks

ERIC Educational Resources Information Center

Ke, Weimao

2010-01-01

Amid the rapid growth of information today is the increasing challenge for people to survive and navigate its magnitude. Dynamics and heterogeneity of large information spaces such as the Web challenge information retrieval in these environments. Collection of information in advance and centralization of IR operations are hardly possible because…

Evaluation and Decentralised Governance: Examples of Inspections in Polycentric Education Systems

ERIC Educational Resources Information Center

Ehren, M. C. M.; Janssens, F. J. G.; Brown, M.; McNamara, G.; O'Hara, J.; Shevlin, P.

2017-01-01

Across Europe schools and other service providers increasingly operate in networks to provide inclusive education or develop and implement more localized school-to-school improvement models. As some education systems move towards more decentralized decision-making where multiple actors have an active role in steering and governing schools, the…

Analysis of production-inventory decisions in a decentralized supply chain with price-dependent demand

NASA Astrophysics Data System (ADS)

Kurdhi, N. A.; Irsanianto, S. T.; Sutanto

2017-01-01

In this paper, we consider a production-inventory supply chain system with single-manufacturer and single-retailer. There are many types of contract that guarantee the supply chain. However, the administrative costs of the contract are usually neglected in real situation. The additional gain from integration may not cover the extra administrative costs may not addressed to supply chain. Therefore, a Stackelberg game and RFM policy are examined in order to investigate its performance on supply chain. The RFM policy is applied because its administrative costs are lower than othe policies. Although RFM policy is not capable of coordinating the channel, it leads to considerable improvements over the channel. The purpose of this research is to present a model of integrated policy, in which the goal is to maximize the whole system profit, and to evaluate decentralized-Stackelberg and RFM policies, in which individual firms in the supply chain have their own objectives and decisions to optimize.

[Regional health systems management: a case study in Rio Grande do Sul, Brazil].

PubMed

Lima, Juliano de Carvalho; Rivera, Francisco Javier Uribe

2006-10-01

This article analyzes the management system in a health district in the State of Rio Grande do Sul, Brazil, through qualitative analysis, using a case study as the methodology and macro-organization theory as the analytical framework. For the current management system in the 6th Health Region, a clear mission statement and wide acceptance by health workers are facilitating factors for the current organizational practices within the health system. Nevertheless, the way health coordinators are currently prioritizing their time has diverted necessary resources from critical problems towards more remedial issues. The 6th Health Region has encouraged social control (or public oversight) in order to improve accountability. However, there is room for improvement in quality assurance management, since there were no well-defined goals, objectives, or accountability. Decentralized consultancy provided to the municipalities and the funding model itself have both promoted decentralization and autonomy, although the strategy requires better regional integration and greater commitment in managerial practices.

Long range healthcare capacity planning in the Netherlands. The case of radiotherapy.

PubMed

Postma, T J B M; Terpstra, S

2002-01-01

This contribution discusses centralization vs. decentralization in healthcare strategic decision making, focusing on long-range planning of facilities for radiotherapy. The radiotherapy case illustrates that more centralized, comprehensive, and systematic planning and strategic decisions making may be necessary to account for inputs of various parties and decision-making levels in this area. The expertise required cannot generally be found at a local or even regional level. It requires initiatives from coordinating healthcare institutions such as the Health Council and other professional organizations.

Understanding crowd-powered search groups: a social network perspective.

PubMed

Zhang, Qingpeng; Wang, Fei-Yue; Zeng, Daniel; Wang, Tao

2012-01-01

Crowd-powered search is a new form of search and problem solving scheme that involves collaboration among a potentially large number of voluntary Web users. Human flesh search (HFS), a particular form of crowd-powered search originated in China, has seen tremendous growth since its inception in 2001. HFS presents a valuable test-bed for scientists to validate existing and new theories in social computing, sociology, behavioral sciences, and so forth. In this research, we construct an aggregated HFS group, consisting of the participants and their relationships in a comprehensive set of identified HFS episodes. We study the topological properties and the evolution of the aggregated network and different sub-groups in the network. We also identify the key HFS participants according to a variety of measures. We found that, as compared with other online social networks, HFS participant network shares the power-law degree distribution and small-world property, but with a looser and more distributed organizational structure, leading to the diversity, decentralization, and independence of HFS participants. In addition, the HFS group has been becoming increasingly decentralized. The comparisons of different HFS sub-groups reveal that HFS participants collaborated more often when they conducted the searches in local platforms or the searches requiring a certain level of professional knowledge background. On the contrary, HFS participants did not collaborate much when they performed the search task in national platforms or the searches with general topics that did not require specific information and learning. We also observed that the key HFS information contributors, carriers, and transmitters came from different groups of HFS participants.

The Database Query Support Processor (QSP)

NASA Technical Reports Server (NTRS)

1993-01-01

The number and diversity of databases available to users continues to increase dramatically. Currently, the trend is towards decentralized, client server architectures that (on the surface) are less expensive to acquire, operate, and maintain than information architectures based on centralized, monolithic mainframes. The database query support processor (QSP) effort evaluates the performance of a network level, heterogeneous database access capability. Air Force Material Command's Rome Laboratory has developed an approach, based on ANSI standard X3.138 - 1988, 'The Information Resource Dictionary System (IRDS)' to seamless access to heterogeneous databases based on extensions to data dictionary technology. To successfully query a decentralized information system, users must know what data are available from which source, or have the knowledge and system privileges necessary to find out this information. Privacy and security considerations prohibit free and open access to every information system in every network. Even in completely open systems, time required to locate relevant data (in systems of any appreciable size) would be better spent analyzing the data, assuming the original question was not forgotten. Extensions to data dictionary technology have the potential to more fully automate the search and retrieval for relevant data in a decentralized environment. Substantial amounts of time and money could be saved by not having to teach users what data resides in which systems and how to access each of those systems. Information describing data and how to get it could be removed from the application and placed in a dedicated repository where it belongs. The result simplified applications that are less brittle and less expensive to build and maintain. Software technology providing the required functionality is off the shelf. The key difficulty is in defining the metadata required to support the process. The database query support processor effort will provide quantitative data on the amount of effort required to implement an extended data dictionary at the network level, add new systems, adapt to changing user needs, and provide sound estimates on operations and maintenance costs and savings.

Decentralized cooperative TOA/AOA target tracking for hierarchical wireless sensor networks.

PubMed

Chen, Ying-Chih; Wen, Chih-Yu

2012-11-08

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

Resiliently evolving supply-demand networks

NASA Astrophysics Data System (ADS)

Rubido, Nicolás; Grebogi, Celso; Baptista, Murilo S.

2014-01-01

The ability to design a transport network such that commodities are brought from suppliers to consumers in a steady, optimal, and stable way is of great importance for distribution systems nowadays. In this work, by using the circuit laws of Kirchhoff and Ohm, we provide the exact capacities of the edges that an optimal supply-demand network should have to operate stably under perturbations, i.e., without overloading. The perturbations we consider are the evolution of the connecting topology, the decentralization of hub sources or sinks, and the intermittence of supplier and consumer characteristics. We analyze these conditions and the impact of our results, both on the current United Kingdom power-grid structure and on numerically generated evolving archetypal network topologies.

Robust recognition of handwritten numerals based on dual cooperative network

NASA Technical Reports Server (NTRS)

Lee, Sukhan; Choi, Yeongwoo

1992-01-01

An approach to robust recognition of handwritten numerals using two operating parallel networks is presented. The first network uses inputs in Cartesian coordinates, and the second network uses the same inputs transformed into polar coordinates. How the proposed approach realizes the robustness to local and global variations of input numerals by handling inputs both in Cartesian coordinates and in its transformed Polar coordinates is described. The required network structures and its learning scheme are discussed. Experimental results show that by tracking only a small number of distinctive features for each teaching numeral in each coordinate, the proposed system can provide robust recognition of handwritten numerals.

[The virtual library in equity, health, and human development].

PubMed

Valdés, América

2002-01-01

This article attempts to describe the rationale that has led to the development of information sources dealing with equity, health, and human development in countries of Latin America and the Caribbean within the context of the Virtual Health Library (Biblioteca Virtual en Salud, BVS). Such information sources include the scientific literature, databases in printed and electronic format, institutional directories and lists of specialists, lists of events and courses, distance education programs, specialty journals and bulletins, as well as other means of disseminating health information. The pages that follow deal with the development of a Virtual Library in Equity, Health, and Human Development, an effort rooted in the conviction that decision-making and policy geared toward achieving greater equity in health must, of necessity, be based on coherent, well-organized, and readily accessible first-rate scientific information. Information is useless unless it is converted into knowledge that benefits society. The Virtual Library in Equity, Health, and Human Development is a coordinated effort to develop a decentralized regional network of scientific information sources, with strict quality control, from which public officials can draw data and practical examples that can help them set health and development policies geared toward achieving greater equity for all.

Providing Continuity of Care for Chronic Diseases in the Aftermath of Katrina: From Field Experience to Policy Recommendations

PubMed Central

Arrieta, Martha I.; Foreman, Rachel D.; Crook, Errol D.; Icenogle, Marjorie L.

2014-01-01

This study sought to elicit challenges and solutions in the provision of health care to those with chronic diseases after Hurricane Katrina in coastal Alabama and Mississippi. In-depth interviews with 30 health and social service providers (key informants) and 4 focus groups with patients with chronic diseases were conducted. Subsequently an advisory panel of key informants was convened. Findings were summarized and key informants submitted additional feedback. The chronic diseases identified as medical management priorities by key informants were mental health, diabetes mellitus, hypertension, respiratory illness, end-stage renal disease, cardiovascular disease, and cancer. The most frequently mentioned barrier to providing care was maintaining continuity of medications. Contributing factors were inadequate information (inaccessible medical records, poor patient knowledge) and financial constraints. Implemented or suggested solutions included relaxation of insurance limitations preventing advance prescription refills; better predisaster patient education to improve medical knowledge; promotion of personal health records; support for information technology systems at community health centers, in particular electronic medical records; improved allocation of donated medications/medical supplies (centralized coordination, decentralized distribution); and networking between local responders and external aid. PMID:19865042

[The health system of Brazil].

PubMed

Montekio, Víctor Becerril; Medina, Guadalupe; Aquino, Rosana

2011-01-01

This paper describes the Brazilian health system, which includes a public sector covering almost 75% of the population and an expanding private sector offering health services to the rest of the population. The public sector is organized around the Sistema Único de Saúde (SUS) and it is financed with general taxes and social contributions collected by the three levels of government (federal, state and municipal). SUS provides health care through a decentralized network of clinics, hospitals and other establishments, as well as through contracts with private providers. SUS is also responsible for the coordination of the public sector. The private sector includes a system of insurance schemes known as Supplementary Health which is financed by employers and/or households: group medicine (companies and households), medical cooperatives, the so called Self-Administered Plans (companies) and individual insurance plans.The private sector also includes clinics, hospitals and laboratories offering services on out-of-pocket basis mostly used by the high-income population. This paper also describes the resources of the system, the stewardship activities developed by the Ministry of Health and other actors, and the most recent policy innovations implemented in Brazil, including the programs saúde da Familia and Mais Saúde.

Network-induced oscillatory behavior in material flow networks and irregular business cycles

NASA Astrophysics Data System (ADS)

Helbing, Dirk; Lämmer, Stefen; Witt, Ulrich; Brenner, Thomas

2004-11-01

Network theory is rapidly changing our understanding of complex systems, but the relevance of topological features for the dynamic behavior of metabolic networks, food webs, production systems, information networks, or cascade failures of power grids remains to be explored. Based on a simple model of supply networks, we offer an interpretation of instabilities and oscillations observed in biological, ecological, economic, and engineering systems. We find that most supply networks display damped oscillations, even when their units—and linear chains of these units—behave in a nonoscillatory way. Moreover, networks of damped oscillators tend to produce growing oscillations. This surprising behavior offers, for example, a different interpretation of business cycles and of oscillating or pulsating processes. The network structure of material flows itself turns out to be a source of instability, and cyclical variations are an inherent feature of decentralized adjustments.

On the decentralized observer/controller strategy for disturbance rejection

NASA Astrophysics Data System (ADS)

Faria, Cassio T.; Dong, ZhongZhe; Zhang, Xueji

2017-04-01

Centralized controllers and state estimation strategies are the most common topology implemented for disturbance rejection in smart systems. Although this architecture has been proven to be feasible the advances in computation power and size of logic devices can also enable the implementation of decentralized strategies which, on a large scale, can lead to an overall reliability increase of the system. The goal of this paper is to present this concept within the field of disturbance rejection for smart systems and to explore its capabilities and bottlenecks. A simple example is carried out for a composite plate with two controller/estimator centers. Simulation is used to validate the efficacy of the topology and a design procedure is proposed to guarantee the consensus of the agents within the network.

Patch Transporter: Incentivized, Decentralized Software Patch System for WSN and IoT Environments

PubMed Central

Lee, JongHyup

2018-01-01

In the complicated settings of WSN (Wireless Sensor Networks) and IoT (Internet of Things) environments, keeping a number of heterogeneous devices updated is a challenging job, especially with respect to effectively discovering target devices and rapidly delivering the software updates. In this paper, we convert the traditional software update process to a distributed service. We set an incentive system for faithfully transporting the patches to the recipient devices. The incentive system motivates independent, self-interested transporters for helping the devices to be updated. To ensure the system correctly operates, we employ the blockchain system that enforces the commitment in a decentralized manner. We also present a detailed specification for the proposed protocol and validate it by model checking and simulations for correctness. PMID:29438337

Patch Transporter: Incentivized, Decentralized Software Patch System for WSN and IoT Environments.

PubMed

Lee, JongHyup

2018-02-13

[-12]In the complicated settings of WSN (Wireless Sensor Networks) and IoT (Internet of Things) environments, keeping a number of heterogeneous devices updated is a challenging job, especially with respect to effectively discovering target devices and rapidly delivering the software updates. In this paper, we convert the traditional software update process to a distributed service. We set an incentive system for faithfully transporting the patches to the recipient devices. The incentive system motivates independent, self-interested transporters for helping the devices to be updated. To ensure the system correctly operates, we employ the blockchain system that enforces the commitment in a decentralized manner. We also present a detailed specification for the proposed protocol and validate it by model checking and simulations for correctness.

Distributed Synchronization Control of Multiagent Systems With Unknown Nonlinearities.

PubMed

Su, Shize; Lin, Zongli; Garcia, Alfredo

2016-01-01

This paper revisits the distributed adaptive control problem for synchronization of multiagent systems where the dynamics of the agents are nonlinear, nonidentical, unknown, and subject to external disturbances. Two communication topologies, represented, respectively, by a fixed strongly-connected directed graph and by a switching connected undirected graph, are considered. Under both of these communication topologies, we use distributed neural networks to approximate the uncertain dynamics. Decentralized adaptive control protocols are then constructed to solve the cooperative tracker problem, the problem of synchronization of all follower agents to a leader agent. In particular, we show that, under the proposed decentralized control protocols, the synchronization errors are ultimately bounded, and their ultimate bounds can be reduced arbitrarily by choosing the control parameter appropriately. Simulation study verifies the effectiveness of our proposed protocols.

The influence of pore structure parameters on the digital core recovery degree

NASA Astrophysics Data System (ADS)

Xia, Huifen; Zhao, Ling; Sun, Yanyu; Yuan, Shi

2017-05-01

Constructing digital core in the research of water flooding or polymer flooding oil displacement efficiency has its unique advantage. Using mercury injection experiment measured pore throat size distribution frequency, coordination number measured by CT scanning method and imbibition displacement method is used to measure the wettability of the data, on the basis of considering pore throat ratio, wettability, using the principle of adaptive porosity, on the basis of fitting the permeability to complete the construction of digital core. The results show that the model of throat distribution is concentrated water flooding recovery degree is higher, and distribution is more decentralized model polymer flooding recovery degree is higher. Around the same number of PV in poly, coordination number model of water flooding and polymer flooding recovery degree is higher.

34 CFR 412.1 - What is the National Network for Curriculum Coordination in Vocational and Technical Education?

Code of Federal Regulations, 2011 CFR

2011-07-01

... 34 Education 3 2011-07-01 2011-07-01 false What is the National Network for Curriculum... EDUCATION NATIONAL NETWORK FOR CURRICULUM COORDINATION IN VOCATIONAL AND TECHNICAL EDUCATION General § 412.1 What is the National Network for Curriculum Coordination in Vocational and Technical Education? The...

34 CFR 412.1 - What is the National Network for Curriculum Coordination in Vocational and Technical Education?

Code of Federal Regulations, 2010 CFR

2010-07-01

... 34 Education 3 2010-07-01 2010-07-01 false What is the National Network for Curriculum... EDUCATION NATIONAL NETWORK FOR CURRICULUM COORDINATION IN VOCATIONAL AND TECHNICAL EDUCATION General § 412.1 What is the National Network for Curriculum Coordination in Vocational and Technical Education? The...

Space shuttle program information control and retrieval system feasibility study report

NASA Technical Reports Server (NTRS)

Lingle, C. P.

1973-01-01

The feasibility of having a common information management network for space shuttle data, is studied. Identified are the information types required, sources and users of the information, and existing techniques for acquiring, storing and retrieving the data. The study concluded that a decentralized system is feasible, and described a recommended development plan for it.

United States societal experiments via the Communications Technology Satellite

NASA Technical Reports Server (NTRS)

Donoughe, P. L.

1976-01-01

After a brief description of the Communication Technology Satellite and its U.S. coverage, the U.S. societal experiments via the CTS are discussed. These include education (college curriculum sharing, and project interchange), health care (biomedical communications, health communications, and communication support for decentralized education), and community and special experiments (satellite library information network, and transportable earth terminal).

Initial Clinician Reports of the Bottom-Up Dissemination of an Evidence-Based Intervention for Early Childhood Trauma

ERIC Educational Resources Information Center

David, Paula; Schiff, Miriam

2018-01-01

Background: Bottom-up dissemination (BUD) of evidence based treatments (EBT), entailing the spread of an intervention through a peer network in a decentralized manner, is an under-reported phenomenon in the professional literature. Objective: This paper presents findings from a study researching the feasibility of BUD of an evidence-based…

Advanced Decentralized Water/Energy Network Design for Sustainable Infrastructure presentation at the 2012 National Association of Home Builders (NAHB) International Builders'Show

EPA Science Inventory

A university/industry panel will report on the progress and findings of a fivesteve-year project funded by the US Environmental Protection Agency. The project's end product will be a Web-based, 3D computer-simulated residential environment with a decision support system to assist...

A cloud-based data network approach for translational cancer research.

PubMed

Xing, Wei; Tsoumakos, Dimitrios; Ghanem, Moustafa

2015-01-01

We develop a new model and associated technology for constructing and managing self-organizing data to support translational cancer research studies. We employ a semantic content network approach to address the challenges of managing cancer research data. Such data is heterogeneous, large, decentralized, growing and continually being updated. Moreover, the data originates from different information sources that may be partially overlapping, creating redundancies as well as contradictions and inconsistencies. Building on the advantages of elasticity of cloud computing, we deploy the cancer data networks on top of the CELAR Cloud platform to enable more effective processing and analysis of Big cancer data.

Decentralized adaptive neural control for high-order interconnected stochastic nonlinear time-delay systems with unknown system dynamics.

PubMed

Si, Wenjie; Dong, Xunde; Yang, Feifei

2018-03-01

This paper is concerned with the problem of decentralized adaptive backstepping state-feedback control for uncertain high-order large-scale stochastic nonlinear time-delay systems. For the control design of high-order large-scale nonlinear systems, only one adaptive parameter is constructed to overcome the over-parameterization, and neural networks are employed to cope with the difficulties raised by completely unknown system dynamics and stochastic disturbances. And then, the appropriate Lyapunov-Krasovskii functional and the property of hyperbolic tangent functions are used to deal with the unknown unmatched time-delay interactions of high-order large-scale systems for the first time. At last, on the basis of Lyapunov stability theory, the decentralized adaptive neural controller was developed, and it decreases the number of learning parameters. The actual controller can be designed so as to ensure that all the signals in the closed-loop system are semi-globally uniformly ultimately bounded (SGUUB) and the tracking error converges in the small neighborhood of zero. The simulation example is used to further show the validity of the design method. Copyright © 2018 Elsevier Ltd. All rights reserved.

[Construction of the Brazilian Sanitary Surveillance System: arguments to debate].

PubMed

De Seta, Marismary Horsth; Dain, Sulamis

2010-11-01

This paper analyzes the Brazilian Sanitary Surveillance System as an arrangement aimed at regulating and reducing health risks associated with consumption of products, use of health services and the environment. Historical, political and tax aspects were considered and their development compared with the National Health Surveillance System, which has received strong international cooperation. The comparison was based on the trajectory of their national systems and related federal agencies, as well as on criteria adopted for decentralization. The central category of analysis is federative coordination and was based on the framework of federalism and intergovernmental relations. The institutional context of health and sanitary surveillance presents strong political competition, instability in the project and probable reduction of the ability of federal coordination after the Pact for Health. The National Sanitary Surveillance System due to its nature of public good and high externality in its field of action requires federal coordination for increasing the regional and local cooperation, also because of the structural heterogeneity of Brazilian municipalities.

Decentralized sensor fusion for Ubiquitous Networking Robotics in Urban Areas.

PubMed

Sanfeliu, Alberto; Andrade-Cetto, Juan; Barbosa, Marco; Bowden, Richard; Capitán, Jesús; Corominas, Andreu; Gilbert, Andrew; Illingworth, John; Merino, Luis; Mirats, Josep M; Moreno, Plínio; Ollero, Aníbal; Sequeira, João; Spaan, Matthijs T J

2010-01-01

In this article we explain the architecture for the environment and sensors that has been built for the European project URUS (Ubiquitous Networking Robotics in Urban Sites), a project whose objective is to develop an adaptable network robot architecture for cooperation between network robots and human beings and/or the environment in urban areas. The project goal is to deploy a team of robots in an urban area to give a set of services to a user community. This paper addresses the sensor architecture devised for URUS and the type of robots and sensors used, including environment sensors and sensors onboard the robots. Furthermore, we also explain how sensor fusion takes place to achieve urban outdoor execution of robotic services. Finally some results of the project related to the sensor network are highlighted.

Topological patterns in street networks of self-organized urban settlements

NASA Astrophysics Data System (ADS)

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.

Consensus positive position feedback control for vibration attenuation of smart structures

NASA Astrophysics Data System (ADS)

Omidi, Ehsan; Nima Mahmoodi, S.

2015-04-01

This paper presents a new network-based approach for active vibration control in smart structures. In this approach, a network with known topology connects collocated actuator/sensor elements of the smart structure to one another. Each of these actuators/sensors, i.e., agent or node, is enhanced by a separate multi-mode positive position feedback (PPF) controller. The decentralized PPF controlled agents collaborate with each other in the designed network, under a certain consensus dynamics. The consensus constraint forces neighboring agents to cooperate with each other such that the disagreement between the time-domain actuation of the agents is driven to zero. The controller output of each agent is calculated using state-space variables; hence, optimal state estimators are designed first for the proposed observer-based consensus PPF control. The consensus controller is numerically investigated for a flexible smart structure, i.e., a thin aluminum beam that is clamped at its both ends. Results demonstrate that the consensus law successfully imposes synchronization between the independently controlled agents, as the disagreements between the decentralized PPF controller variables converge to zero in a short time. The new consensus PPF controller brings extra robustness to vibration suppression in smart structures, where malfunctions of an agent can be compensated for by referencing the neighboring agents’ performance. This is demonstrated in the results by comparing the new controller with former centralized PPF approach.

A flexible, open, decentralized system for digital pathology networks.

PubMed

Schuler, Robert; Smith, David E; Kumaraguruparan, Gowri; Chervenak, Ann; Lewis, Anne D; Hyde, Dallas M; Kesselman, Carl

2012-01-01

High-resolution digital imaging is enabling digital archiving and sharing of digitized microscopy slides and new methods for digital pathology. Collaborative research centers, outsourced medical services, and multi-site organizations stand to benefit from sharing pathology data in a digital pathology network. Yet significant technological challenges remain due to the large size and volume of digitized whole slide images. While information systems do exist for managing local pathology laboratories, they tend to be oriented toward narrow clinical use cases or offer closed ecosystems around proprietary formats. Few solutions exist for networking digital pathology operations. Here we present a system architecture and implementation of a digital pathology network and share results from a production system that federates major research centers.

A Flexible, Open, Decentralized System for Digital Pathology Networks

PubMed Central

SMITH, David E.; KUMARAGURUPARAN, Gowri; CHERVENAK, Ann; LEWIS, Anne D.; HYDE, Dallas M.; KESSELMAN, Carl

2014-01-01

High-resolution digital imaging is enabling digital archiving and sharing of digitized microscopy slides and new methods for digital pathology. Collaborative research centers, outsourced medical services, and multi-site organizations stand to benefit from sharing pathology data in a digital pathology network. Yet significant technological challenges remain due to the large size and volume of digitized whole slide images. While information systems do exist for managing local pathology laboratories, they tend to be oriented toward narrow clinical use cases or offer closed ecosystems around proprietary formats. Few solutions exist for networking digital pathology operations. Here we present a system architecture and implementation of a digital pathology network and share results from a production system that federates major research centers. PMID:22941985

A Game-Theoretic Response Strategy for Coordinator Attack in Wireless Sensor Networks

PubMed Central

Liu, Jianhua; Yue, Guangxue; Shang, Huiliang; Li, Hongjie

2014-01-01

The coordinator is a specific node that controls the whole network and has a significant impact on the performance in cooperative multihop ZigBee wireless sensor networks (ZWSNs). However, the malicious node attacks coordinator nodes in an effort to waste the resources and disrupt the operation of the network. Attacking leads to a failure of one round of communication between the source nodes and destination nodes. Coordinator selection is a technique that can considerably defend against attack and reduce the data delivery delay, and increase network performance of cooperative communications. In this paper, we propose an adaptive coordinator selection algorithm using game and fuzzy logic aiming at both minimizing the average number of hops and maximizing network lifetime. The proposed game model consists of two interrelated formulations: a stochastic game for dynamic defense and a best response policy using evolutionary game formulation for coordinator selection. The stable equilibrium best policy to response defense is obtained from this game model. It is shown that the proposed scheme can improve reliability and save energy during the network lifetime with respect to security. PMID:25105171

A game-theoretic response strategy for coordinator attack in wireless sensor networks.

PubMed

Liu, Jianhua; Yue, Guangxue; Shen, Shigen; Shang, Huiliang; Li, Hongjie

2014-01-01

The coordinator is a specific node that controls the whole network and has a significant impact on the performance in cooperative multihop ZigBee wireless sensor networks (ZWSNs). However, the malicious node attacks coordinator nodes in an effort to waste the resources and disrupt the operation of the network. Attacking leads to a failure of one round of communication between the source nodes and destination nodes. Coordinator selection is a technique that can considerably defend against attack and reduce the data delivery delay, and increase network performance of cooperative communications. In this paper, we propose an adaptive coordinator selection algorithm using game and fuzzy logic aiming at both minimizing the average number of hops and maximizing network lifetime. The proposed game model consists of two interrelated formulations: a stochastic game for dynamic defense and a best response policy using evolutionary game formulation for coordinator selection. The stable equilibrium best policy to response defense is obtained from this game model. It is shown that the proposed scheme can improve reliability and save energy during the network lifetime with respect to security.

The financial performance of hospitals belonging to health networks and systems.

PubMed

Bazzoli, G J; Chan, B; Shortell, S M; D'Aunno, T

2000-01-01

The U.S. health industry is experiencing substantial restructuring through ownership consolidation and development of new forms of interorganizational relationships. Using an established taxonomy of health networks and systems, this paper develops and tests four hypotheses related to hospital financial performance. Consistent with our predictions, we find that hospitals in health systems that had unified ownership generally had better financial performance than hospitals in contractually based health networks. Among health network hospitals, those belonging to highly centralized networks had better financial performance than those belonging to more decentralized networks. However, health system hospitals in moderately centralized systems performed better than those in highly centralized systems. Finally, hospitals in networks or systems with little differentiation or centralization experienced the poorest financial performance. These results are consistent with resource dependence, transaction cost economics, and institutional theories of organizational behavior, and provide a conceptual and empirical baseline for future research.

Self-organizing network services with evolutionary adaptation.

PubMed

Nakano, Tadashi; Suda, Tatsuya

2005-09-01

This paper proposes a novel framework for developing adaptive and scalable network services. In the proposed framework, a network service is implemented as a group of autonomous agents that interact in the network environment. Agents in the proposed framework are autonomous and capable of simple behaviors (e.g., replication, migration, and death). In this paper, an evolutionary adaptation mechanism is designed using genetic algorithms (GAs) for agents to evolve their behaviors and improve their fitness values (e.g., response time to a service request) to the environment. The proposed framework is evaluated through simulations, and the simulation results demonstrate the ability of autonomous agents to adapt to the network environment. The proposed framework may be suitable for disseminating network services in dynamic and large-scale networks where a large number of data and services need to be replicated, moved, and deleted in a decentralized manner.

A Hybrid OFDM-TDM Architecture with Decentralized Dynamic Bandwidth Allocation for PONs

PubMed Central

Cevik, Taner

2013-01-01

One of the major challenges of passive optical networks is to achieve a fair arbitration mechanism that will prevent possible collisions from occurring at the upstream channel when multiple users attempt to access the common fiber at the same time. Therefore, in this study we mainly focus on fair bandwidth allocation among users, and present a hybrid Orthogonal Frequency Division Multiplexed/Time Division Multiplexed architecture with a dynamic bandwidth allocation scheme that provides satisfying service qualities to the users depending on their varying bandwidth requirements. Unnecessary delays in centralized schemes occurring during bandwidth assignment stage are eliminated by utilizing a decentralized approach. Instead of sending bandwidth demands to the optical line terminal (OLT) which is the only competent authority, each optical network unit (ONU) runs the same bandwidth demand determination algorithm. ONUs inform each other via signaling channel about the status of their queues. This information is fed to the bandwidth determination algorithm which is run by each ONU in a distributed manner. Furthermore, Light Load Penalty, which is a phenomenon in optical communications, is mitigated by limiting the amount of bandwidth that an ONU can demand. PMID:24194684

Synchronization and coordination of sequences in two neural ensembles

NASA Astrophysics Data System (ADS)

Venaille, Antoine; Varona, Pablo; Rabinovich, Mikhail I.

2005-06-01

There are many types of neural networks involved in the sequential motor behavior of animals. For high species, the control and coordination of the network dynamics is a function of the higher levels of the central nervous system, in particular the cerebellum. However, in many cases, especially for invertebrates, such coordination is the result of direct synaptic connections between small circuits. We show here that even the chaotic sequential activity of small model networks can be coordinated by electrotonic synapses connecting one or several pairs of neurons that belong to two different networks. As an example, we analyzed the coordination and synchronization of the sequential activity of two statocyst model networks of the marine mollusk Clione. The statocysts are gravity sensory organs that play a key role in postural control of the animal and the generation of a complex hunting motor program. Each statocyst network was modeled by a small ensemble of neurons with Lotka-Volterra type dynamics and nonsymmetric inhibitory interactions. We studied how two such networks were synchronized by electrical coupling in the presence of an external signal which lead to winnerless competition among the neurons. We found that as a function of the number and the strength of connections between the two networks, it is possible to coordinate and synchronize the sequences that each network generates with its own chaotic dynamics. In spite of the chaoticity, the coordination of the signals is established through an activation sequence lock for those neurons that are active at a particular instant of time.

Overview of the state of the art of constructed wetlands for decentralized wastewater management in Brazil.

PubMed

Machado, A I; Beretta, M; Fragoso, R; Duarte, E

2017-02-01

Conventional wastewater treatment plants (WWTPs) commonly require large capital investments as well as operation and maintenance costs. Constructed wetlands (CWs) appear as a cost-effective treatment, since they can remove a broad range of contaminants by a combination of physical, chemical and biological processes with a low cost. Therefore, CWs can be successfully applied for decentralized wastewater treatment in regions with low population density and/or with large land availability as Brazil. The present work provides a review of thirty nine studies developed on CWs implemented in Brazil to remove wastewater contaminants. Brazil current sanitation data is also considered to evaluate the potential role of CWs as decentralized wastewater treatment. Performance of CWs was evaluated according to (i) type of wetland system, (ii) different support matrix (iii) vegetation species and (iv) removal efficiency of chemical oxygen demand (COD), biological oxygen demand (BOD 5 ), nitrogen (N), and phosphorus (P). The reviewed CWs in overall presented good efficiencies, whereas H-CWs achieved the highest removals for P, while the higher results for N were attained on VF-CW and for COD and BOD 5 on HF-CW. Therefore, was concluded that CWs are an interesting solution for decentralized wastewater treatment in Brazil since it has warm temperatures, extensive radiation hours and available land. Additionally, the low percentage of population with access to the sewage network in the North and Northeast regions makes these systems especially suitable. Hence, the further implementation of CW is encouraged by the authors in regions with similar characteristics as Brazil. Copyright © 2016 Elsevier Ltd. All rights reserved.

The 2016 World Humanitarian Summit Report Card: Both Failing Marks and Substantive Gains for an Increasingly Globalized Humanitarian Landscape

PubMed Central

V. Canyon, Deon; Burkle, Frederick M.

2016-01-01

Outcomes of the World Humanitarian Summit were mixed with some refreshing new directions being endorsed and a lack of systemic reform. The selective agenda and OCHAs lack of success in engaging pre-meeting political participation not only hampered the Summit’s ability to deal with global issues and institutional reform, but also alienated it from leading aid agencies and governments. The UN’s failure to commit to humanitarian principles and global disarray of the humanitarian system indicates the need for extensive reform or a new global humanitarian body. This agency needs to employ a decentralized model to manage aid funds, assume coordination of international responses, resolve civil-military coordination, cater for people affected by both conflict and disasters, and professionalize the humanitarian career.  PMID:27679738

Automating the deconfliction of jamming and spectrum management

NASA Astrophysics Data System (ADS)

Segner, Samuel M.

1988-12-01

Powerful airborne and ground based jammers are being fielded by all services and nations as part of their intelligence/electronic warfare (I/EW) combat capability. For their survivability, these I/EW systems operate far from the FLOT; this creates rather large denial areas to friendly forces when they jam. Manual coordination between IE/W managers and spectrum managers is not practical to take on targets of opportunities or track the intended enemy victims when these victims counter by frequency maneuvers. Two possible architectures, one centralized, the other decentralized, are explored as is the applicability of the electromagnetic compatibility (EMC) software developed for the U.S. Army Automatic Tactical Frequency Engineering System (ATFES) pilot program. The proposed approach is to apply the principles of the Joint Commanders EW Staff (JCEWS). The initial simplified software to demonstrate the computer aided coordination at VHF is explained.

A brittle star-like robot capable of immediately adapting to unexpected physical damage.

PubMed

Kano, Takeshi; Sato, Eiki; Ono, Tatsuya; Aonuma, Hitoshi; Matsuzaka, Yoshiya; Ishiguro, Akio

2017-12-01

A major challenge in robotic design is enabling robots to immediately adapt to unexpected physical damage. However, conventional robots require considerable time (more than several tens of seconds) for adaptation because the process entails high computational costs. To overcome this problem, we focus on a brittle star-a primitive creature with expendable body parts. Brittle stars, most of which have five flexible arms, occasionally lose some of them and promptly coordinate the remaining arms to escape from predators. We adopted a synthetic approach to elucidate the essential mechanism underlying this resilient locomotion. Specifically, based on behavioural experiments involving brittle stars whose arms were amputated in various ways, we inferred the decentralized control mechanism that self-coordinates the arm motions by constructing a simple mathematical model. We implemented this mechanism in a brittle star-like robot and demonstrated that it adapts to unexpected physical damage within a few seconds by automatically coordinating its undamaged arms similar to brittle stars. Through the above-mentioned process, we found that physical interaction between arms plays an essential role for the resilient inter-arm coordination of brittle stars. This finding will help develop resilient robots that can work in inhospitable environments. Further, it provides insights into the essential mechanism of resilient coordinated motions characteristic of animal locomotion.

A brittle star-like robot capable of immediately adapting to unexpected physical damage

PubMed Central

Sato, Eiki; Ono, Tatsuya; Aonuma, Hitoshi; Matsuzaka, Yoshiya; Ishiguro, Akio

2017-01-01

A major challenge in robotic design is enabling robots to immediately adapt to unexpected physical damage. However, conventional robots require considerable time (more than several tens of seconds) for adaptation because the process entails high computational costs. To overcome this problem, we focus on a brittle star—a primitive creature with expendable body parts. Brittle stars, most of which have five flexible arms, occasionally lose some of them and promptly coordinate the remaining arms to escape from predators. We adopted a synthetic approach to elucidate the essential mechanism underlying this resilient locomotion. Specifically, based on behavioural experiments involving brittle stars whose arms were amputated in various ways, we inferred the decentralized control mechanism that self-coordinates the arm motions by constructing a simple mathematical model. We implemented this mechanism in a brittle star-like robot and demonstrated that it adapts to unexpected physical damage within a few seconds by automatically coordinating its undamaged arms similar to brittle stars. Through the above-mentioned process, we found that physical interaction between arms plays an essential role for the resilient inter-arm coordination of brittle stars. This finding will help develop resilient robots that can work in inhospitable environments. Further, it provides insights into the essential mechanism of resilient coordinated motions characteristic of animal locomotion. PMID:29308250

NDEx 2.0: A Clearinghouse for Research on Cancer Pathways.

PubMed

Pratt, Dexter; Chen, Jing; Pillich, Rudolf; Rynkov, Vladimir; Gary, Aaron; Demchak, Barry; Ideker, Trey

2017-11-01

We present NDEx 2.0, the latest release of the Network Data Exchange (NDEx) online data commons (www.ndexbio.org) and the ways in which it can be used to (i) improve the quality and abundance of biological networks relevant to the cancer research community; (ii) provide a medium for collaboration involving networks; and (iii) facilitate the review and dissemination of networks. We describe innovations addressing the challenges of an online data commons: scalability, data integration, data standardization, control of content and format by authors, and decentralized mechanisms for review. The practical use of NDEx is presented in the context of a novel strategy to foster network-oriented communities of interest in cancer research by adapting methods from academic publishing and social media. Cancer Res; 77(21); e58-61. ©2017 AACR . ©2017 American Association for Cancer Research.

Decentralized Sensor Fusion for Ubiquitous Networking Robotics in Urban Areas

PubMed Central

Sanfeliu, Alberto; Andrade-Cetto, Juan; Barbosa, Marco; Bowden, Richard; Capitán, Jesús; Corominas, Andreu; Gilbert, Andrew; Illingworth, John; Merino, Luis; Mirats, Josep M.; Moreno, Plínio; Ollero, Aníbal; Sequeira, João; Spaan, Matthijs T.J.

2010-01-01

In this article we explain the architecture for the environment and sensors that has been built for the European project URUS (Ubiquitous Networking Robotics in Urban Sites), a project whose objective is to develop an adaptable network robot architecture for cooperation between network robots and human beings and/or the environment in urban areas. The project goal is to deploy a team of robots in an urban area to give a set of services to a user community. This paper addresses the sensor architecture devised for URUS and the type of robots and sensors used, including environment sensors and sensors onboard the robots. Furthermore, we also explain how sensor fusion takes place to achieve urban outdoor execution of robotic services. Finally some results of the project related to the sensor network are highlighted. PMID:22294927

Network Performance and Coordination in the Health, Education, Telecommunications System. Satellite Technology Demonstration, Technical Report No. 0422.

ERIC Educational Resources Information Center

Braunstein, Jean; Janky, James M.

This paper describes the network coordination for the Health, Education, Telecommunications (HET) system. Specifically, it discusses HET network performance as a function of a specially-developed coordination system which was designed to link terrestrial equipment to satellite operations centers. Because all procedures and equipment developed for…

A Novel Re-keying Function Protocol (NRFP) For Wireless Sensor Network Security.

PubMed

Abdullah, Maan Younis; Hua, Gui Wei; Alsharabi, Naif

2008-12-04

This paper describes a novel re-keying function protocol (NRFP) for wireless sensor network security. A re-keying process management system for sensor networks is designed to support in-network processing. The design of the protocol is motivated by decentralization key management for wireless sensor networks (WSNs), covering key deployment, key refreshment, and key establishment. NRFP supports the establishment of novel administrative functions for sensor nodes that derive/re-derive a session key for each communication session. The protocol proposes direct connection, in-direct connection and hybrid connection. NRFP also includes an efficient protocol for local broadcast authentication based on the use of one-way key chains. A salient feature of the authentication protocol is that it supports source authentication without precluding in-network processing. Security and performance analysis shows that it is very efficient in computation, communication and storage and, that NRFP is also effective in defending against many sophisticated attacks.

NEV supply chain coordination and sustainability considering sales effort and risk aversion under the CVaR criterion

PubMed Central

Xu, Xingzhong

2018-01-01

In a two-echelon new energy vehicle (NEV) supply chain consisting of a risk-neutral manufacturer and a risk-averse retailer, the coordination and sustainability problem is investigated. The risk-averse retailer, who makes sales effort and undertakes the incurred effort cost, decides the order quantity and sales effort level under the Conditional Value-at-Risk (CVaR) criterion. We derive the optimal centralized decisions of a vertically integrated supply chain where the retailer is owned by the manufacturer. Taking such a centralized case as the benchmark, we prove that the subsidy-sharing-based wholesale price (SS-WP) contract fails to coordinate the NEV supply chain under the decentralized case where the retailer makes decisions independently. Then we design a subsidy-sharing-based sales rebate/penalty (SS-SRP) contract and derive the contract parameters to achieve coordination. We evaluate the coordination efficiency of this contract and find that a well-designed SS-SRP contract can promote the NEV sales and lead to a Pareto-improving win-win situation for both the NEV manufacturer and retailer compared to the non-coordination case. A series of numerical experiments are carried out to compare the effects of significant parameters under the SS-WP and SS-SRP contract and provide additional observations and implications, including an indication of the necessary conditions to sustainably maintain the NEV supply chain. PMID:29912926

Inter-organizational network in Indonesia during disasters: Examples and research agenda on disaster management

NASA Astrophysics Data System (ADS)

Bisri, M. B. F.

2017-02-01

Indonesia is facing various type of disaster risks, each with its own nature (sudden or slow onset, purely natural or man-made) and coverage of affected areas. Whereas science, technology and engineering intervention requires different modalities for each hazard, little has been known on whether the institutional setup and organizations involvement requires a different or similar types of intervention. Under a decentralized disaster management system, potential involvement of international organizations in response and growing diversified organizations involved in responding to disaster, it is important to understand the nature of inter-organizational network during various type of disasters in Indonesia. This paper is mixture of in-depth literature review and multiple case studies on utilization of social network analysis (SNA) in modelling inter-organizational network during various disasters in Indonesia.

An economic model of friendship and enmity for measuring social balance in networks

NASA Astrophysics Data System (ADS)

Lee, Kyu-Min; Shin, Euncheol; You, Seungil

2017-12-01

We propose a dynamic economic model of networks where agents can be friends or enemies with one another. This is a decentralized relationship model in that agents decide whether to change their relationships so as to minimize their imbalanced triads. In this model, there is a single parameter, which we call social temperature, that captures the degree to which agents care about social balance in their relationships. We show that the global structure of relationship configuration converges to a unique stationary distribution. Using this stationary distribution, we characterize the maximum likelihood estimator of the social temperature parameter. Since the estimator is computationally challenging to calculate from real social network datasets, we provide a simple simulation algorithm and verify its performance with real social network datasets.

Kinetic products in coordination networks: ab initio X-ray powder diffraction analysis.

PubMed

Martí-Rujas, Javier; Kawano, Masaki

2013-02-19

Porous coordination networks are materials that maintain their crystal structure as molecular "guests" enter and exit their pores. They are of great research interest with applications in areas such as catalysis, gas adsorption, proton conductivity, and drug release. As with zeolite preparation, the kinetic states in coordination network preparation play a crucial role in determining the final products. Controlling the kinetic state during self-assembly of coordination networks is a fundamental aspect of developing further functionalization of this class of materials. However, unlike for zeolites, there are few structural studies reporting the kinetic products made during self-assembly of coordination networks. Synthetic routes that produce the necessary selectivity are complex. The structural knowledge obtained from X-ray crystallography has been crucial for developing rational strategies for design of organic-inorganic hybrid networks. However, despite the explosive progress in the solid-state study of coordination networks during the last 15 years, researchers still do not understand many chemical reaction processes because of the difficulties in growing single crystals suitable for X-ray diffraction: Fast precipitation can lead to kinetic (metastable) products, but in microcrystalline form, unsuitable for single crystal X-ray analysis. X-ray powder diffraction (XRPD) routinely is used to check phase purity, crystallinity, and to monitor the stability of frameworks upon guest removal/inclusion under various conditions, but rarely is used for structure elucidation. Recent advances in structure determination of microcrystalline solids from ab initio XRPD have allowed three-dimensional structure determination when single crystals are not available. Thus, ab initio XRPD structure determination is becoming a powerful method for structure determination of microcrystalline solids, including porous coordination networks. Because of the great interest across scientific disciplines in coordination networks, especially porous coordination networks, the ability to determine crystal structures when the crystals are not suitable for single crystal X-ray analysis is of paramount importance. In this Account, we report the potential of kinetic control to synthesize new coordination networks and we describe ab initio XRPD structure determination to characterize these networks' crystal structures. We describe our recent work on selective instant synthesis to yield kinetically controlled porous coordination networks. We demonstrate that instant synthesis can selectively produce metastable networks that are not possible to synthesize by conventional solution chemistry. Using kinetic products, we provide mechanistic insights into thermally induced (573-723 K) (i.e., annealing method) structural transformations in porous coordination networks as well as examples of guest exchange/inclusion reactions. Finally, we describe a memory effect that allows the transfer of structural information from kinetic precursor structures to thermally stable structures through amorphous intermediate phases. We believe that ab initio XRPD structure determination will soon be used to investigate chemical processes that lead intrinsically to microcrystalline solids, which up to now have not been fully understood due to the unavailability of single crystals. For example, only recently have researchers used single-crystal X-ray diffraction to elucidate crystal-to-crystal chemical reactions taking place in the crystalline scaffold of coordination networks. The potential of ab initio X-ray powder diffraction analysis goes beyond single-crystal-to-single-crystal processes, potentially allowing members of this field to study intriguing in situ reactions, such as reactions within pores.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ding, Fei; Jiang, Huaiguang; Tan, Jin

This paper proposes an event-driven approach for reconfiguring distribution systems automatically. Specifically, an optimal synchrophasor sensor placement (OSSP) is used to reduce the number of synchrophasor sensors while keeping the whole system observable. Then, a wavelet-based event detection and location approach is used to detect and locate the event, which performs as a trigger for network reconfiguration. With the detected information, the system is then reconfigured using the hierarchical decentralized approach to seek for the new optimal topology. In this manner, whenever an event happens the distribution network can be reconfigured automatically based on the real-time information that is observablemore » and detectable.« less

Self-organizing intelligent network of smart electrical heating devices as an alternative to traditional ways of heating

NASA Astrophysics Data System (ADS)

Zaslavsky, Aleksander M.; Tkachov, Viktor V.; Protsenko, Stanislav M.; Bublikov, Andrii V.; Suleimenov, Batyrbek; Orshubekov, Nurbek; Gromaszek, Konrad

2017-08-01

The paper considers the problem of automated decentralized distribution of the electric energy among unlimited-power electric heaters providing the given temperature distribution within the zones of monitored object heating in the context of maximum use of electric power which limiting level is time-dependent randomly. Principles of collective selforganization automata for solving the problem are analyzed. It has been shown that after all the automata make decision, equilibrium of Nash type is attained when unused power within the electric network is not more than a power of any non-energized electric heater.

Distributed Leadership in a Maltese College: The Voices of Those among Whom Leadership Is "Distributed" and Who Concurrently Narrate Themselves as Leadership "Distributors"

ERIC Educational Resources Information Center

Mifsud, Denise

2017-01-01

In the unfolding Maltese education scenario of decentralization and school networking, I explore distributed leadership as it occurs at the college level through the leaders' narrative and performance in an investigation of the power relations among the different-tiered leaders. This article uses data from the case study of a Maltese college…

Enabling Service Discovery in a Federation of Systems: WS-Discovery Case Study

DTIC Science & Technology

2014-06-01

found that Pastry [3] coupled with SCRIBE [4] provides everything we require from the overlay network: Pastry nodes form a decentralized, self...application-independent manner. Furthermore, Pastry provides mechanisms that support and facilitate application-specific object replication, caching, and fault...recovery. Add SCRIBE to Pastry , and you get a generic, scalable and efficient group communication and event notification system providing

78 FR 24154 - Notice of Availability of a National Animal Health Laboratory Network Reorganization Concept Paper

Federal Register 2010, 2011, 2012, 2013, 2014

2013-04-24

...] Notice of Availability of a National Animal Health Laboratory Network Reorganization Concept Paper AGENCY... Network (NAHLN) for public review and comment. The NAHLN is a nationally coordinated network and... Coordinator, National Animal Health Laboratory Network, Veterinary Services, APHIS, 2140 Centre Avenue...

Adding signals to coordinated traffic signal systems.

DOT National Transportation Integrated Search

1983-08-01

The purpose of this research was to investigate the effect of adding or : removing traffic signals within a coordinated, signal-controlled street network. : The report includes a discussion of coordinated signal systems; arterial street : network con...

Wireless and real-time structural damage detection: A novel decentralized method for wireless sensor networks

NASA Astrophysics Data System (ADS)

Avci, Onur; Abdeljaber, Osama; Kiranyaz, Serkan; Hussein, Mohammed; Inman, Daniel J.

2018-06-01

Being an alternative to conventional wired sensors, wireless sensor networks (WSNs) are extensively used in Structural Health Monitoring (SHM) applications. Most of the Structural Damage Detection (SDD) approaches available in the SHM literature are centralized as they require transferring data from all sensors within the network to a single processing unit to evaluate the structural condition. These methods are found predominantly feasible for wired SHM systems; however, transmission and synchronization of huge data sets in WSNs has been found to be arduous. As such, the application of centralized methods with WSNs has been a challenge for engineers. In this paper, the authors are presenting a novel application of 1D Convolutional Neural Networks (1D CNNs) on WSNs for SDD purposes. The SDD is successfully performed completely wireless and real-time under ambient conditions. As a result of this, a decentralized damage detection method suitable for wireless SHM systems is proposed. The proposed method is based on 1D CNNs and it involves training an individual 1D CNN for each wireless sensor in the network in a format where each CNN is assigned to process the locally-available data only, eliminating the need for data transmission and synchronization. The proposed damage detection method operates directly on the raw ambient vibration condition signals without any filtering or preprocessing. Moreover, the proposed approach requires minimal computational time and power since 1D CNNs merge both feature extraction and classification tasks into a single learning block. This ability is prevailingly cost-effective and evidently practical in WSNs considering the hardware systems have been occasionally reported to suffer from limited power supply in these networks. To display the capability and verify the success of the proposed method, large-scale experiments conducted on a laboratory structure equipped with a state-of-the-art WSN are reported.

Decentralized energy systems for clean electricity access

NASA Astrophysics Data System (ADS)

Alstone, Peter; Gershenson, Dimitry; Kammen, Daniel M.

2015-04-01

Innovative approaches are needed to address the needs of the 1.3 billion people lacking electricity, while simultaneously transitioning to a decarbonized energy system. With particular focus on the energy needs of the underserved, we present an analytic and conceptual framework that clarifies the heterogeneous continuum of centralized on-grid electricity, autonomous mini- or community grids, and distributed, individual energy services. A historical analysis shows that the present day is a unique moment in the history of electrification where decentralized energy networks are rapidly spreading, based on super-efficient end-use appliances and low-cost photovoltaics. We document how this evolution is supported by critical and widely available information technologies, particularly mobile phones and virtual financial services. These disruptive technology systems can rapidly increase access to basic electricity services and directly inform the emerging Sustainable Development Goals for quality of life, while simultaneously driving action towards low-carbon, Earth-sustaining, inclusive energy systems.

Performance Evaluation of AODV with Blackhole Attack

NASA Astrophysics Data System (ADS)

Dara, Karuna

2010-11-01

A Mobile Ad Hoc Network (MANET) is a temporary network set up by a wireless mobile computers moving arbitrary in the places that have no network infrastructure. These nodes maintain connectivity in a decentralized manner. Since the nodes communicate with each other, they cooperate by forwarding data packets to other nodes in the network. Thus the nodes find a path to the destination node using routing protocols. However, due to security vulnerabilities of the routing protocols, mobile ad-hoc networks are unprotected to attacks of the malicious nodes. One of these attacks is the Black Hole Attack against network integrity absorbing all data packets in the network. Since the data packets do not reach the destination node on account of this attack, data loss will occur. In this paper, we simulated the black hole attack in various mobile ad-hoc network scenarios using AODV routing protocol of MANET and have tried to find a effect if number of nodes are increased with increase in malicious nodes.

Porphyrin coordination polymer nanospheres and nanorods

DOEpatents

Wang, Zhongchun; Shelnutt, John A.; Medforth, Craig J.

2012-12-04

A porphyrin coordination polymer nanostructure comprising a network of pyridyl porphyrin molecules and coordinating metal ions coordinatively bound through the pyridyl groups. In some embodiments, the porphyrins are metalloporphyrins. A variety of nanostructures are formed by the network polymer, including nanospheres, polygonal nanostructures, nanorods, and nanofibers, depending on a variety of factors including coordination metal ion, porphyrin type, metal of the metalloporphyrin, and degree of agitation during nanostructure formation. Reduction of coordinating metal ions may be used to form metal nanoparticles on the coordination polymer nanostructure.

Porphyrin coordination polymer nanospheres and nanorods

DOEpatents

Wang, Zhongchun; Shelnutt, John A.; Medforth, Craig J.

2013-09-10

A porphyrin coordination polymer nanostructure comprising a network of pyridyl porphyrin molecules and coordinating metal ions coordinatively bound through the pyridyl groups. In some embodiments, the porphyrins are metalloporphyrins. A variety of nanostructures are formed by the network polymer, including nanospheres, polygonal nanostructures, nanorods, and nanofibers, depending on a variety of factors including coordination metal ion, porphyrin type, metal of the metalloporphyrin, and degree of agitation during nanostructure formation. Reduction of coordinating metal ions may be used to form metal nanoparticles on the coordination polymer nanostructure.

Coordinated neuronal activity enhances corticocortical communication

PubMed Central

Zandvakili, Amin; Kohn, Adam

2015-01-01

Summary Relaying neural signals between cortical areas is central to cognition and sensory processing. The temporal coordination of activity in a source population has been suggested to determine corticocortical signaling efficacy, but others have argued that coordination is functionally irrelevant. We reasoned that if coordination significantly influenced signaling, spiking in downstream networks should be preceded by transiently elevated coordination in a source population. We developed a metric to quantify network coordination in brief epochs, and applied it to simultaneous recordings of neuronal populations in cortical areas V1 and V2 of the macaque monkey. Spiking in the input layers of V2 was preceded by brief epochs of elevated V1 coordination, but this was not the case in other layers of V2. Our results indicate that V1 coordination influences its signaling to direct downstream targets, but that coordinated V1 epochs do not propagate through multiple downstream networks as in some corticocortical signaling schemes. PMID:26291164

Learning and coordinating in a multilayer network

PubMed Central

Lugo, Haydée; Miguel, Maxi San

2015-01-01

We introduce a two layer network model for social coordination incorporating two relevant ingredients: a) different networks of interaction to learn and to obtain a pay-off, and b) decision making processes based both on social and strategic motivations. Two populations of agents are distributed in two layers with intralayer learning processes and playing interlayer a coordination game. We find that the skepticism about the wisdom of crowd and the local connectivity are the driving forces to accomplish full coordination of the two populations, while polarized coordinated layers are only possible for all-to-all interactions. Local interactions also allow for full coordination in the socially efficient Pareto-dominant strategy in spite of being the riskier one. PMID:25585934

DoD Electronic Data Interchange (EDI) Convention: ASC X12 Transaction Set 836 Contract Award (Version 003010)

DTIC Science & Technology

1993-01-01

upon designation of DoD Activity Address Code (DoDAAC) or other code coordinated with the value-added network (VAN). Mandatory ISA06 106 Interc.ange...coordinated with the value-added network (VAN). Non-DoD activities use identification code qualified by ISA05 and coordinated with the VAN. Mandatory...designation of DoD Activity Address Code (DoDAAC) or other code coordinated with the value-added network (VAN). Mandatory ISA08 107 Interchange Receiver

An approach for heterogeneous and loosely coupled geospatial data distributed computing

NASA Astrophysics Data System (ADS)

Chen, Bin; Huang, Fengru; Fang, Yu; Huang, Zhou; Lin, Hui

2010-07-01

Most GIS (Geographic Information System) applications tend to have heterogeneous and autonomous geospatial information resources, and the availability of these local resources is unpredictable and dynamic under a distributed computing environment. In order to make use of these local resources together to solve larger geospatial information processing problems that are related to an overall situation, in this paper, with the support of peer-to-peer computing technologies, we propose a geospatial data distributed computing mechanism that involves loosely coupled geospatial resource directories and a term named as Equivalent Distributed Program of global geospatial queries to solve geospatial distributed computing problems under heterogeneous GIS environments. First, a geospatial query process schema for distributed computing as well as a method for equivalent transformation from a global geospatial query to distributed local queries at SQL (Structured Query Language) level to solve the coordinating problem among heterogeneous resources are presented. Second, peer-to-peer technologies are used to maintain a loosely coupled network environment that consists of autonomous geospatial information resources, thus to achieve decentralized and consistent synchronization among global geospatial resource directories, and to carry out distributed transaction management of local queries. Finally, based on the developed prototype system, example applications of simple and complex geospatial data distributed queries are presented to illustrate the procedure of global geospatial information processing.

Experimenting with Decentralization: The Politics of Change.

ERIC Educational Resources Information Center

Wohlstetter, Priscilla

The relationship between the political context of school districts and their choices of decentralization policy is explored in this paper. It was expected that district politics would affect decentralization policies in two ways: the form of decentralization adopted and the degree of change. The decision to decentralize in three large urban school…

D Coordinate Transformation Using Artificial Neural Networks

NASA Astrophysics Data System (ADS)

Konakoglu, B.; Cakır, L.; Gökalp, E.

2016-10-01

Two coordinate systems used in Turkey, namely the ED50 (European Datum 1950) and ITRF96 (International Terrestrial Reference Frame 1996) coordinate systems. In most cases, it is necessary to conduct transformation from one coordinate system to another. The artificial neural network (ANN) is a new method for coordinate transformation. One of the biggest advantages of the ANN is that it can determine the relationship between two coordinate systems without a mathematical model. The aim of this study was to investigate the performances of three different ANN models (Feed Forward Back Propagation (FFBP), Cascade Forward Back Propagation (CFBP) and Radial Basis Function Neural Network (RBFNN)) with regard to 2D coordinate transformation. To do this, three data sets were used for the same study area, the city of Trabzon. The coordinates of data sets were measured in the ED50 and ITRF96 coordinate systems by using RTK-GPS technique. Performance of each transformation method was investigated by using the coordinate differences between the known and estimated coordinates. The results showed that the ANN algorithms can be used for 2D coordinate transformation in cases where optimum model parameters are selected.

A Novel Re-keying Function Protocol (NRFP) For Wireless Sensor Network Security

PubMed Central

Abdullah, Maan Younis; Hua, Gui Wei; Alsharabi, Naif

2008-01-01

This paper describes a novel re-keying function protocol (NRFP) for wireless sensor network security. A re-keying process management system for sensor networks is designed to support in-network processing. The design of the protocol is motivated by decentralization key management for wireless sensor networks (WSNs), covering key deployment, key refreshment, and key establishment. NRFP supports the establishment of novel administrative functions for sensor nodes that derive/re-derive a session key for each communication session. The protocol proposes direct connection, in-direct connection and hybrid connection. NRFP also includes an efficient protocol for local broadcast authentication based on the use of one-way key chains. A salient feature of the authentication protocol is that it supports source authentication without precluding innetwork processing. Security and performance analysis shows that it is very efficient in computation, communication and storage and, that NRFP is also effective in defending against many sophisticated attacks. PMID:27873963

The design of water markets when instream flows have value.

PubMed

Murphy, James J; Dinar, Ariel; Howitt, Richard E; Rassenti, Stephen J; Smith, Vernon L; Weinberg, Marca

2009-02-01

The main objective of this paper is to design and test a decentralized exchange mechanism that generates the location-specific pricing necessary to achieve efficient allocations in the presence of instream flow values. Although a market-oriented approach has the potential to improve upon traditional command and control regulations, questions remain about how these rights-based institutions can be implemented such that the potential gains from liberalized trade can be realized. This article uses laboratory experiments to test three different water market institutions designed to incorporate instream flow values into the allocation mechanism through active participation of an environmental trader. The smart, computer-coordinated market described herein offers the potential to significantly reduce coordination problems and transaction costs associated with finding mutually beneficial trades that satisfy environmental constraints. We find that direct environmental participation in the market can achieve highly efficient and stable outcomes, although the potential does exist for the environmental agent to influence outcomes.

Decentralized Formation Flying Control in a Multiple-Team Hierarchy

NASA Technical Reports Server (NTRS)

Mueller, Joseph .; Thomas, Stephanie J.

2005-01-01

This paper presents the prototype of a system that addresses these objectives-a decentralized guidance and control system that is distributed across spacecraft using a multiple-team framework. The objective is to divide large clusters into teams of manageable size, so that the communication and computational demands driven by N decentralized units are related to the number of satellites in a team rather than the entire cluster. The system is designed to provide a high-level of autonomy, to support clusters with large numbers of satellites, to enable the number of spacecraft in the cluster to change post-launch, and to provide for on-orbit software modification. The distributed guidance and control system will be implemented in an object-oriented style using MANTA (Messaging Architecture for Networking and Threaded Applications). In this architecture, tasks may be remotely added, removed or replaced post-launch to increase mission flexibility and robustness. This built-in adaptability will allow software modifications to be made on-orbit in a robust manner. The prototype system, which is implemented in MATLAB, emulates the object-oriented and message-passing features of the MANTA software. In this paper, the multiple-team organization of the cluster is described, and the modular software architecture is presented. The relative dynamics in eccentric reference orbits is reviewed, and families of periodic, relative trajectories are identified, expressed as sets of static geometric parameters. The guidance law design is presented, and an example reconfiguration scenario is used to illustrate the distributed process of assigning geometric goals to the cluster. Next, a decentralized maneuver planning approach is presented that utilizes linear-programming methods to enact reconfiguration and coarse formation keeping maneuvers. Finally, a method for performing online collision avoidance is discussed, and an example is provided to gauge its performance.

Health policies and federative gaps in Brazil: an analysis of regional capacity of services delivery.

PubMed

Ribeiro, José Mendes; Moreira, Marcelo Rasga; Ouverney, Assis Mafort; Silva, Cosme Marcelo Furtado Passos da

2017-04-01

This paper analyzes Brazilian health regions according to their service delivery capacity from the debate on the crisis of cooperative federalism in the SUS that resulted from decentralizing process established in the 1988 Constitution. Service delivery capacity tracer indicators were selected by regions and statistical analyses evidenced greater regional capacity in hospital care and large asymmetries with regard to the availability of physicians, high complexity equipment and private insurance coverage. In conclusion,we argue that further solutions are required to strengthen governmental capacity to reduce regional inequalities throughincreased central coordination.

Value-Based Emergency Management.

PubMed

Corrigan, Zachary; Winslow, Walter; Miramonti, Charlie; Stephens, Tim

2016-02-01

This article touches on the complex and decentralized network that is the US health care system and how important it is to include emergency management in this network. By aligning the overarching incentives of opposing health care organizations, emergency management can become resilient to up-and-coming changes in reimbursement, staffing, and network ownership. Coalitions must grasp the opportunity created by changes in value-based purchasing and impending Centers for Medicare and Medicaid Services emergency management rules to engage payers, physicians, and executives. Hope and faith in doing good is no longer enough for preparedness and health care coalitions; understanding how physicians are employed and health care is delivered and paid for is now necessary. Incentivizing preparedness through value-based compensation systems will become the new standard for emergency management.

Monitoring and control requirement definition study for Dispersed Storage and Generation (DSG). Volume 4, appendix C: Identification from utility visits of present and future approaches to integration of DSG into distribution networks

NASA Technical Reports Server (NTRS)

1980-01-01

Visits to four utilities concerned with the use of DSG power sources on their distribution networks yielded useful impressions of present and future approaches to the integration of DSGs into electrical distribution network. Different approaches to future utility systems with DSG are beginning to take shape. The new DSG sources will be in decentralized locations with some measure of centralized control. The utilities have yet to establish firmly the communication and control means or their organization. For the present, the means for integrating the DSGs and their associated monitoring and control equipment into a unified system have not been decided.

Venezuela: from doctrine to dialogue to participation in the processes of regional development.

PubMed

Allor, D J

1984-01-01

The growing toward decentralization and democratization of development planning in Venezuela was discussed. Venezuela has a long tradition of rule by a strong centralized authority. Currently, the Office of the President is vested with considerable power, despite the existence of an elected legislator and an independent judiciary. The president rules by decree. State legislatures are elected, but governors of the states are appointed by the president. There are also elected municipal councils. Both state and municipal governments are almost fully dependent on the federal government for both their operating and capital investment budgets. Development programs are administered through 2 systems. Specific programs are administered by almost 100 different institutes and enterprises. The activities of these various programs are coordinated by administrative bodies at the state and federal level. The 2nd administrative system operates at the regional and federal levels. The administrative body at the federal level is the Central Office for Coordination and Planning and was established by Presidential Decree in 1958. This body prepares and coordinates all national development plans. The administrative bodies at the regional level are the Regional Organizations for Development. These bodies were created in specific regions through a series of legislative acts commencing in 1969 and continuing into the present. The development of these regional bodies represented a 1st step toward decentralization. Decree 478, promulgated in 1980, further promoted the decentalization of developmental planning. The decree established a series of assemblies and councils at various levels. A National Council of Regional Development was created at the federal level, and a Regional Council of Development was established at the regional level. At the state level an Assembly of Participation was organized, and at the municipal level a Committee of Citizen Participation was established. Neighborhood associations were mentioned in the decree, but their role was not formalized. This series of newly established bodies plays a role in both advisory and administrative processes. The advisory process begins at the lowest level, and local concerns are expressed upward through the hierarchy. The administrative process flows in the opposite direction. Participation remains highly formalized and is restricted to the participation of recognized leaders and organizations. For example, members of the Assembly of Participation include the state governor, representatives of municipal councils, and representatives of various industrial and commercial organizations. Despite the formal nature of the participation, the 1980 Decree clearly exhibited the trend toward decentralization predicted by John Freeman in his analysis of Venezuelan political structure and published in a book entitled "venezuela: From doctrine to Dialogue." Increased pressure will now be exerted for broader community participation in the development process, and eventually development planning will focus on the equitable distribution of development benefits rather than on the maximization of economic growth.

Fuzzy Adaptive Decentralized Optimal Control for Strict Feedback Nonlinear Large-Scale Systems.

PubMed

Sun, Kangkang; Sui, Shuai; Tong, Shaocheng

2018-04-01

This paper considers the optimal decentralized fuzzy adaptive control design problem for a class of interconnected large-scale nonlinear systems in strict feedback form and with unknown nonlinear functions. The fuzzy logic systems are introduced to learn the unknown dynamics and cost functions, respectively, and a state estimator is developed. By applying the state estimator and the backstepping recursive design algorithm, a decentralized feedforward controller is established. By using the backstepping decentralized feedforward control scheme, the considered interconnected large-scale nonlinear system in strict feedback form is changed into an equivalent affine large-scale nonlinear system. Subsequently, an optimal decentralized fuzzy adaptive control scheme is constructed. The whole optimal decentralized fuzzy adaptive controller is composed of a decentralized feedforward control and an optimal decentralized control. It is proved that the developed optimal decentralized controller can ensure that all the variables of the control system are uniformly ultimately bounded, and the cost functions are the smallest. Two simulation examples are provided to illustrate the validity of the developed optimal decentralized fuzzy adaptive control scheme.

Distributed sensor coordination for advanced energy systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tumer, Kagan

Motivation: The ability to collect key system level information is critical to the safe, efficient and reliable operation of advanced power systems. Recent advances in sensor technology have enabled some level of decision making directly at the sensor level. However, coordinating large numbers of sensors, particularly heterogeneous sensors, to achieve system level objectives such as predicting plant efficiency, reducing downtime or predicting outages requires sophisticated coordination algorithms. Indeed, a critical issue in such systems is how to ensure the interaction of a large number of heterogenous system components do not interfere with one another and lead to undesirable behavior. Objectivesmore » and Contributions: The long-term objective of this work is to provide sensor deployment, coordination and networking algorithms for large numbers of sensors to ensure the safe, reliable, and robust operation of advanced energy systems. Our two specific objectives are to: 1. Derive sensor performance metrics for heterogeneous sensor networks. 2. Demonstrate effectiveness, scalability and reconfigurability of heterogeneous sensor network in advanced power systems. The key technical contribution of this work is to push the coordination step to the design of the objective functions of the sensors, allowing networks of heterogeneous sensors to be controlled. By ensuring that the control and coordination is not specific to particular sensor hardware, this approach enables the design and operation of large heterogeneous sensor networks. In addition to the coordination coordination mechanism, this approach allows the system to be reconfigured in response to changing needs (e.g., sudden external events requiring new responses) or changing sensor network characteristics (e.g., sudden changes to plant condition). Impact: The impact of this work extends to a large class of problems relevant to the National Energy Technology Laboratory including sensor placement, heterogeneous sensor coordination, and sensor network control in advanced power systems. Each application has specific needs, but they all share the one crucial underlying problem: how to ensure that the interactions of a large number of heterogenous agents lead to coordinated system behavior. This proposal describes a new paradigm that addresses that very issue in a systematic way. Key Results and Findings: All milestones have been completed. Our results demonstrate that by properly shaping agent objective functions, we can develop large (up to 10,000 devices) heterogeneous sensor networks with key desirable properties. The first milestone shows that properly choosing agent-specific objective functions increases system performance by up to 99.9% compared to global evaluations. The second milestone shows evolutionary algorithms learn excellent sensor network coordination policies prior to network deployment, and these policies can be refined online once the network is deployed. The third milestone shows the resulting sensor networks networks are extremely robust to sensor noise, where networks with up to 25% sensor noise are capable of providing measurements with errors on the order of 10⁻³. The fourth milestone shows the resulting sensor networks are extremely robust to sensor failure, with 25% of the sensors in the system failing resulting in no significant performance losses after system reconfiguration.« less

Decentralized Network Interdiction Games

DTIC Science & Technology

2015-12-31

approach is termed as the sample average approximation ( SAA ) method, and theories on the asymptotic convergence to the original problem’s optimal...used in the SAA method’s convergence. While we provided detailed proof of such convergence in [P3], a side benefit of the proof is that it weakens the...conditions required when applying the general SAA approach to the block-structured stochastic programming problem 17. As the conditions known in the

Social adaptation in multi-agent model of linguistic categorization is affected by network information flow.

PubMed

Zubek, Julian; Denkiewicz, Michał; Barański, Juliusz; Wróblewski, Przemysław; Rączaszek-Leonardi, Joanna; Plewczynski, Dariusz

2017-01-01

This paper explores how information flow properties of a network affect the formation of categories shared between individuals, who are communicating through that network. Our work is based on the established multi-agent model of the emergence of linguistic categories grounded in external environment. We study how network information propagation efficiency and the direction of information flow affect categorization by performing simulations with idealized network topologies optimizing certain network centrality measures. We measure dynamic social adaptation when either network topology or environment is subject to change during the experiment, and the system has to adapt to new conditions. We find that both decentralized network topology efficient in information propagation and the presence of central authority (information flow from the center to peripheries) are beneficial for the formation of global agreement between agents. Systems with central authority cope well with network topology change, but are less robust in the case of environment change. These findings help to understand which network properties affect processes of social adaptation. They are important to inform the debate on the advantages and disadvantages of centralized systems.

Social adaptation in multi-agent model of linguistic categorization is affected by network information flow

PubMed Central

Denkiewicz, Michał; Barański, Juliusz; Wróblewski, Przemysław; Rączaszek-Leonardi, Joanna; Plewczynski, Dariusz

2017-01-01

This paper explores how information flow properties of a network affect the formation of categories shared between individuals, who are communicating through that network. Our work is based on the established multi-agent model of the emergence of linguistic categories grounded in external environment. We study how network information propagation efficiency and the direction of information flow affect categorization by performing simulations with idealized network topologies optimizing certain network centrality measures. We measure dynamic social adaptation when either network topology or environment is subject to change during the experiment, and the system has to adapt to new conditions. We find that both decentralized network topology efficient in information propagation and the presence of central authority (information flow from the center to peripheries) are beneficial for the formation of global agreement between agents. Systems with central authority cope well with network topology change, but are less robust in the case of environment change. These findings help to understand which network properties affect processes of social adaptation. They are important to inform the debate on the advantages and disadvantages of centralized systems. PMID:28809957

Cross-layer model design in wireless ad hoc networks for the Internet of Things.

PubMed

Yang, Xin; Wang, Ling; Xie, Jian; Zhang, Zhaolin

2018-01-01

Wireless ad hoc networks can experience extreme fluctuations in transmission traffic in the Internet of Things, which is widely used today. Currently, the most crucial issues requiring attention for wireless ad hoc networks are making the best use of low traffic periods, reducing congestion during high traffic periods, and improving transmission performance. To solve these problems, the present paper proposes a novel cross-layer transmission model based on decentralized coded caching in the physical layer and a content division multiplexing scheme in the media access control layer. Simulation results demonstrate that the proposed model effectively addresses these issues by substantially increasing the throughput and successful transmission rate compared to existing protocols without a negative influence on delay, particularly for large scale networks under conditions of highly contrasting high and low traffic periods.

Cross-layer model design in wireless ad hoc networks for the Internet of Things

PubMed Central

Wang, Ling; Xie, Jian; Zhang, Zhaolin

2018-01-01

Wireless ad hoc networks can experience extreme fluctuations in transmission traffic in the Internet of Things, which is widely used today. Currently, the most crucial issues requiring attention for wireless ad hoc networks are making the best use of low traffic periods, reducing congestion during high traffic periods, and improving transmission performance. To solve these problems, the present paper proposes a novel cross-layer transmission model based on decentralized coded caching in the physical layer and a content division multiplexing scheme in the media access control layer. Simulation results demonstrate that the proposed model effectively addresses these issues by substantially increasing the throughput and successful transmission rate compared to existing protocols without a negative influence on delay, particularly for large scale networks under conditions of highly contrasting high and low traffic periods. PMID:29734355

U-Form vs. M-Form: How to Understand Decision Autonomy Under Healthcare Decentralization?

PubMed Central

Bustamante, Arturo Vargas

2016-01-01

For more than three decades healthcare decentralization has been promoted in developing countries as a way of improving the financing and delivery of public healthcare. Decision autonomy under healthcare decentralization would determine the role and scope of responsibility of local authorities. Jalal Mohammed, Nicola North, and Toni Ashton analyze decision autonomy within decentralized services in Fiji. They conclude that the narrow decision space allowed to local entities might have limited the benefits of decentralization on users and providers. To discuss the costs and benefits of healthcare decentralization this paper uses the U-form and M-form typology to further illustrate the role of decision autonomy under healthcare decentralization. This paper argues that when evaluating healthcare decentralization, it is important to determine whether the benefits from decentralization are greater than its costs. The U-form and M-form framework is proposed as a useful typology to evaluate different types of institutional arrangements under healthcare decentralization. Under this model, the more decentralized organizational form (M-form) is superior if the benefits from flexibility exceed the costs of duplication and the more centralized organizational form (U-form) is superior if the savings from economies of scale outweigh the costly decision-making process from the center to the regions. Budgetary and financial autonomy and effective mechanisms to maintain local governments accountable for their spending behavior are key decision autonomy variables that could sway the cost-benefit analysis of healthcare decentralization. PMID:27694684

Doctors' opinions on clinical coordination between primary and secondary care in the Catalan healthcare system.

PubMed

Aller, Marta-Beatriz; Vargas, Ingrid; Coderch, Jordi; Calero, Sebastià; Cots, Francesc; Abizanda, Mercè; Colomés, Lluís; Farré, Joan; Vázquez-Navarrete, María-Luisa

2017-08-26

To analyse doctors' opinions on clinical coordination between primary and secondary care in different healthcare networks and on the factors influencing it. A qualitative descriptive-interpretative study was conducted, based on semi-structured interviews. A two-stage theoretical sample was designed: 1) healthcare networks with different management models; 2) primary care and secondary care doctors in each network. Final sample size (n = 50) was reached by saturation. A thematic content analysis was conducted. In all networks doctors perceived that primary and secondary care given to patients was coordinated in terms of information transfer, consistency and accessibility to SC following a referral. However, some problems emerged, related to difficulties in acceding non-urgent secondary care changes in prescriptions and the inadequacy of some referrals across care levels. Doctors identified the following factors: 1) organizational influencing factors: coordination is facilitated by mechanisms that facilitate information transfer, communication, rapid access and physical proximity that fosters positive attitudes towards collaboration; coordination is hindered by the insufficient time to use mechanisms, unshared incentives in prescription and, in two networks, the change in the organizational model; 2) professional factors: clinical skills and attitudes towards coordination. Although doctors perceive that primary and secondary care is coordinated, they also highlighted problems. Identified factors offer valuable insights on where to direct organizational efforts to improve coordination. Copyright © 2017. Publicado por Elsevier España, S.L.U.

Alpha-beta coordination method for collective search

DOEpatents

Goldsmith, Steven Y.

2002-01-01

The present invention comprises a decentralized coordination strategy called alpha-beta coordination. The alpha-beta coordination strategy is a family of collective search methods that allow teams of communicating agents to implicitly coordinate their search activities through a division of labor based on self-selected roles and self-determined status. An agent can play one of two complementary roles. An agent in the alpha role is motivated to improve its status by exploring new regions of the search space. An agent in the beta role is also motivated to improve its status, but is conservative and tends to remain aggregated with other agents until alpha agents have clearly identified and communicated better regions of the search space. An agent can select its role dynamically based on its current status value relative to the status values of neighboring team members. Status can be determined by a function of the agent's sensor readings, and can generally be a measurement of source intensity at the agent's current location. An agent's decision cycle can comprise three sequential decision rules: (1) selection of a current role based on the evaluation of the current status data, (2) selection of a specific subset of the current data, and (3) determination of the next heading using the selected data. Variations of the decision rules produce different versions of alpha and beta behaviors that lead to different collective behavior properties.

Optical zone centration: a retrospective analysis of the excimer laser after three years

NASA Astrophysics Data System (ADS)

Vervecken, Filip; Trau, Rene; Mertens, Erik L.; Vanhorenbeeck, R.; Van Aerde, F.; Zen, J.; Haustrate, F.; Tassignon, Marie J.

1996-12-01

The aim of this study was to evaluate the implication of the mechanical factor 'decentration' on the visual outcome after PRK. 100 eyes of 70 patients were included. The mean decentration was 0.27 mm +/- 0.18. Decentration was less than 0.5 mm in 84 percent of the cases. The importance of the decentration was investigated by the statistical correlation of decentration from the pupilcenter and the visual outcome. We did not find any statistical significant association for decentrations less than 1 mm. Our conclusion is that decentration, if less than 1 mm, does not play an important role in the final visual outcome after PRK.

Collision-free coordination of fiber positioners in multi-object spectrographs

NASA Astrophysics Data System (ADS)

Makarem, Laleh; Kneib, Jean-Paul; Gillet, Denis

2016-07-01

Many fiber-fed spectroscopic survey projects, such as DESI, PFS and MOONS, will use thousands of fiber positioners packed at a focal plane. To maximize observation time, the positioners need to move simultaneously and reach their targets swiftly. We have previously presented a motion planning method based on a decentralized navigation function for the collision-free coordination of the fiber positioners in DESI. In MOONS, the end effector of each positioner handling the fiber can reach the centre of its neighbours. There is therefore a risk of collision with up to 18 surrounding positioners in the chosen dense hexagonal configuration. Moreover, the length of the second arm of the positioner is almost twice the length of the first one. As a result, the geometry of the potential collision zone between two positioners is not limited to the extremity of their end-effector, but surrounds the second arm. In this paper, we modify the navigation function to take into account the larger collision zone resulting from the extended geometrical shape of the positioners. The proposed navigation function takes into account the configuration of the positioners as well as the constraints on the actuators, such as their maximal velocity and their mechanical clearance. Considering the fact that all the positioners' bases are fixed to the focal plane, collisions can occur locally and the risk of collision is limited to the 18 surrounding positioners. The decentralizing motion planning and trajectory generation takes advantage of this limited number of positioners and the locality of collisions, hence significantly reduces the complexity of the algorithm to a linear order. The linear complexity ensures short computation time. In addition, the time needed to move all the positioners to their targets is independent of the number of positioners. These two key advantages of the chosen decentralization approach turn this method to a promising solution for the collision-free motion-planning problem in the next- generation spectroscopic survey projects. A motion planning simulator, exploited as a software prototype, has been developed in Python. The pre-computed collision-free trajectories of the actuators of all the positioners are fed directly from the simulator to the electronics controlling the motors. A successful demonstration of the effectiveness of these trajectories on the real positioners as well as their simulated counterparts are put side by side in the following online video sequence (https://goo.gl/YuwwsE).

The anatomy of urban social networks and its implications in the searchability problem

PubMed Central

Herrera-Yagüe, C.; Schneider, C. M.; Couronné, T.; Smoreda, Z.; Benito, R. M.; Zufiria, P. J.; González, M. C.

2015-01-01

The appearance of large geolocated communication datasets has recently increased our understanding of how social networks relate to their physical space. However, many recurrently reported properties, such as the spatial clustering of network communities, have not yet been systematically tested at different scales. In this work we analyze the social network structure of over 25 million phone users from three countries at three different scales: country, provinces and cities. We consistently find that this last urban scenario presents significant differences to common knowledge about social networks. First, the emergence of a giant component in the network seems to be controlled by whether or not the network spans over the entire urban border, almost independently of the population or geographic extension of the city. Second, urban communities are much less geographically clustered than expected. These two findings shed new light on the widely-studied searchability in self-organized networks. By exhaustive simulation of decentralized search strategies we conclude that urban networks are searchable not through geographical proximity as their country-wide counterparts, but through an homophily-driven community structure. PMID:26035529

The anatomy of urban social networks and its implications in the searchability problem.

PubMed

Herrera-Yagüe, C; Schneider, C M; Couronné, T; Smoreda, Z; Benito, R M; Zufiria, P J; González, M C

2015-06-02

The appearance of large geolocated communication datasets has recently increased our understanding of how social networks relate to their physical space. However, many recurrently reported properties, such as the spatial clustering of network communities, have not yet been systematically tested at different scales. In this work we analyze the social network structure of over 25 million phone users from three countries at three different scales: country, provinces and cities. We consistently find that this last urban scenario presents significant differences to common knowledge about social networks. First, the emergence of a giant component in the network seems to be controlled by whether or not the network spans over the entire urban border, almost independently of the population or geographic extension of the city. Second, urban communities are much less geographically clustered than expected. These two findings shed new light on the widely-studied searchability in self-organized networks. By exhaustive simulation of decentralized search strategies we conclude that urban networks are searchable not through geographical proximity as their country-wide counterparts, but through an homophily-driven community structure.

The Neural Network In Coordinate Transformation

NASA Astrophysics Data System (ADS)

Urusan, Ahmet Yucel

2011-12-01

In international literature, Coordinate operations is divided into two categories. They are coordinate conversion and coordinate transformation. Coordinates converted from coordinate system A to coordinate system B in the same datum (mean origine, scale and axis directions are same) by coordinate conversion. There are two different datum in coordinate transformation. The basis of each datum to a different coordinate reference system. In Coordinate transformation, coordinates are transformed from coordinate reference system A to coordinate referance system B. Geodetic studies based on physical measurements. Coordinate transformation needs identical points which were measured in each coordinate reference system (A and B). However it is difficult (and need a big reserved budget) to measure in some places like as top of mountain, boundry of countries and seaside. In this study, this sample problem solution was researched. The method of learning which is one of the neural network methods, was used for solution of this problem.

Administrative Coordination in Non-Profit Human Service Delivery Networks: The Role of Competition and Trust

PubMed Central

Bunger, Alicia C.

2014-01-01

Non-profit human service organizations operating within the same regional network are often faced with dual pressure to compete as well as coordinate administrative operations (by sharing funding, staff or space) to enhance efficiency. Emerging evidence has demonstrated that competing organizations coordinate, despite the risks. Trust, or perceived trustworthiness between two organizations may mitigate the negative influence of competition on coordination, however there have been few explicit tests of this hypothesis among non-profit organizations. Drawing on quantitative data collected from a network of 36 non-profit children’s behavioral health organizations, this paper empirically tests how competition and perceived trustworthiness interact to influence administrative coordination. Results support the hypothesis that trustworthiness moderates the influence of competition on administrative coordination. Findings suggest that as competing non-profit leaders build trust, the more their agencies coordinate their administrative functions. This study highlights the importance of leaders’ perceptions for organizational strategy. PMID:25349468

Balancing Officer Community Manpower through Decentralization: Granular Programming Revisited (1REV)

DTIC Science & Technology

2017-08-01

supply-demand imbalances Economic theory identifies costs and benefits associated with decentralization. On the benefits side, decentralized decision...patterns rather than costs . Granular programming as a decentralized, market-based initiative The costs and benefits of decentralized (instead of...paygrade-specific rates were based on average MPN costs by paygrade. The benefits of this approach to granular programming are that it is conceptually

Network-Friendly Gossiping

NASA Astrophysics Data System (ADS)

Serbu, Sabina; Rivière, Étienne; Felber, Pascal

The emergence of large-scale distributed applications based on many-to-many communication models, e.g., broadcast and decentralized group communication, has an important impact on the underlying layers, notably the Internet routing infrastructure. To make an effective use of network resources, protocols should both limit the stress (amount of messages) on each infrastructure entity like routers and links, and balance as much as possible the load in the network. Most protocols use application-level metrics such as delays to improve efficiency of content dissemination or routing, but the extend to which such application-centric optimizations help reduce and balance the load imposed to the infrastructure is unclear. In this paper, we elaborate on the design of such network-friendly protocols and associated metrics. More specifically, we investigate random-based gossip dissemination. We propose and evaluate different ways of making this representative protocol network-friendly while keeping its desirable properties (robustness and low delays). Simulations of the proposed methods using synthetic and real network topologies convey and compare their abilities to reduce and balance the load while keeping good performance.

Autonomous smart sensor network for full-scale structural health monitoring

NASA Astrophysics Data System (ADS)

Rice, Jennifer A.; Mechitov, Kirill A.; Spencer, B. F., Jr.; Agha, Gul A.

2010-04-01

The demands of aging infrastructure require effective methods for structural monitoring and maintenance. Wireless smart sensor networks offer the ability to enhance structural health monitoring (SHM) practices through the utilization of onboard computation to achieve distributed data management. Such an approach is scalable to the large number of sensor nodes required for high-fidelity modal analysis and damage detection. While smart sensor technology is not new, the number of full-scale SHM applications has been limited. This slow progress is due, in part, to the complex network management issues that arise when moving from a laboratory setting to a full-scale monitoring implementation. This paper presents flexible network management software that enables continuous and autonomous operation of wireless smart sensor networks for full-scale SHM applications. The software components combine sleep/wake cycling for enhanced power management with threshold detection for triggering network wide tasks, such as synchronized sensing or decentralized modal analysis, during periods of critical structural response.

How does network structure affect partnerships for promoting physical activity? Evidence from Brazil and Colombia.

PubMed

Parra, Diana C; Dauti, Marsela; Harris, Jenine K; Reyes, Lissette; Malta, Deborah C; Brownson, Ross C; Quintero, Mario A; Pratt, Michael

2011-11-01

The objective of this study was to describe the network structure and factors associated with collaboration in two networks that promote physical activity (PA) in Brazil and Colombia. Organizations that focus on studying and promoting PA in Brazil (35) and Colombia (53) were identified using a modified one-step reputational snowball sampling process. Participants completed an on-line survey between December 2008 and March 2009 for the Brazil network, and between April and June 2009 for the Colombia network. Network stochastic modeling was used to investigate the likelihood of reported inter-organizational collaboration. While structural features of networks were significant predictors of collaboration within each network, the coefficients and other network characteristics differed. Brazil's PA network was decentralized with a larger number of shared partnerships. Colombia's PA network was centralized and collaboration was influenced by perceived importance of peer organizations. On average, organizations in the PA network of Colombia reported facing more barriers (1.5 vs. 2.5 barriers) for collaboration. Future studies should focus on how these different network structures affect the implementation and uptake of evidence-based PA interventions. Copyright © 2011 Elsevier Ltd. All rights reserved.

U-Form vs. M-Form: How to Understand Decision Autonomy Under Healthcare Decentralization? Comment on "Decentralisation of Health Services in Fiji: A Decision Space Analysis".

PubMed

Bustamante, Arturo Vargas

2016-06-07

For more than three decades healthcare decentralization has been promoted in developing countries as a way of improving the financing and delivery of public healthcare. Decision autonomy under healthcare decentralization would determine the role and scope of responsibility of local authorities. Jalal Mohammed, Nicola North, and Toni Ashton analyze decision autonomy within decentralized services in Fiji. They conclude that the narrow decision space allowed to local entities might have limited the benefits of decentralization on users and providers. To discuss the costs and benefits of healthcare decentralization this paper uses the U-form and M-form typology to further illustrate the role of decision autonomy under healthcare decentralization. This paper argues that when evaluating healthcare decentralization, it is important to determine whether the benefits from decentralization are greater than its costs. The U-form and M-form framework is proposed as a useful typology to evaluate different types of institutional arrangements under healthcare decentralization. Under this model, the more decentralized organizational form (M-form) is superior if the benefits from flexibility exceed the costs of duplication and the more centralized organizational form (U-form) is superior if the savings from economies of scale outweigh the costly decision-making process from the center to the regions. Budgetary and financial autonomy and effective mechanisms to maintain local governments accountable for their spending behavior are key decision autonomy variables that could sway the cost-benefit analysis of healthcare decentralization. © 2016 by Kerman University of Medical Sciences.

Evaluation of Coordination of Emergency Response Team through the Social Network Analysis. Case Study: Oil and Gas Refinery.

PubMed

Mohammadfam, Iraj; Bastani, Susan; Esaghi, Mahbobeh; Golmohamadi, Rostam; Saee, Ali

2015-03-01

The purpose of this study was to examine the cohesions status of the coordination within response teams in the emergency response team (ERT) in a refinery. For this study, cohesion indicators of social network analysis (SNA; density, degree centrality, reciprocity, and transitivity) were utilized to examine the coordination of the response teams as a whole network. The ERT of this research, which was a case study, included seven teams consisting of 152 members. The required data were collected through structured interviews and were analyzed using the UCINET 6.0 Social Network Analysis Program. The results reported a relatively low number of triple connections, poor coordination with key members, and a high level of mutual relations in the network with low density, all implying that there were low cohesions of coordination in the ERT. The results showed that SNA provided a quantitative and logical approach for the examination of the coordination status among response teams and it also provided a main opportunity for managers and planners to have a clear understanding of the presented status. The research concluded that fundamental efforts were needed to improve the presented situations.

Decentralization and primary health care: some negative implications in developing countries.

PubMed

Collins, C; Green, A

1994-01-01

Decentralization is a highly popular concept, being a key element of Primary Health Care policies. There are, however, certain negative implications of decentralization that must be taken into account. These are analyzed in this article with particular reference to developing countries. The authors criticize the tendency for decentralization to be associated with state limitations, and discuss the dilemma of relating decentralization, which is the enhancement of the different, to equity, which is the promotion of equivalence. Those situations in which decentralization can strengthen political domination are described. The authors conclude by setting out a checklist of warning questions and issues to be taken into account to ensure that decentralization genuinely facilitates the Primary Health Care orientation of health policy.

What supervisors want to know about decentralization.

PubMed

Boissoneau, R; Belton, P

1991-06-01

Many organizations in various industries have tended to move away from strict centralization, yet some centralization is still vital to top management. With 19 of the 22 executives interviewed favoring or implementing some form of decentralization, it is probable that traditionally centralized organizations will follow the trend and begin to decentralize their organizational structures. The incentives and advantages of decentralization are too attractive to ignore. Decentralization provides responsibility, clear objectives, accountability for results, and more efficient and effective decision making. However, one must remember that decentralization can be overextended and that centralization is still viable in certain functions. Finding the correct balance between control and autonomy is a key to decentralization. Too much control and too much autonomy are the primary reasons for decentralization failures. In today's changing, competitive environment, structures must be continuously redefined, with the goal of finding an optimal balance between centralization and decentralization. Organizations are cautioned not to seek out and install a single philosopher-king to impose unified direction, but to unify leadership goals, participation, style, and control to develop improved methods of making all responsible leaders of one mind about the organization's needs and goals.

Challenges in Personalizing and Decentralizing the Web: An Overview of GOSSPLE

NASA Astrophysics Data System (ADS)

Kermarrec, Anne-Marie

Social networks and collaborative tagging systems have taken off at an unexpected scale and speed (Facebook, YouTube, Flickr, Last.fm, Delicious, etc). Web content is now generated by you, me, our friends and millions of others. This represents a revolution in usage and a great opportunity to leverage collaborative knowledge to enhance the user's Internet experience. The GOSSPLE project aims at precisely achieving this: automatically capturing affinities between users that are potentially unknown yet share similar interests, or exhibiting similar behaviors on the Web. This fully personalizes the search process, increasing the ability of a user to find relevant content. This personalization calls for decentralization. (1) Centralized servers might dissuade users from generating new content for they expose their privacy and represent a single point of attack. (2) The amount of information to store grows exponentially with the size of the system and centralized systems cannot sustain storing a growing amount of data at a user granularity. We believe that the salvation can only come from a fully decentralized user centric approach where every participant is entrusted to harvest the Web with information relevant to her own activity. This poses a number of scientific challenges: How to discover similar users, how to define the relevant metrics for such personalization, how to preserve privacy when needed, how to deal with free-riders and misheavior and how to manage efficiently a growing amount of data.

Patient Experiences of Decentralized HIV Treatment and Care in Plateau State, North Central Nigeria: A Qualitative Study

PubMed Central

Kolawole, Grace O.; Gilbert, Hannah N.; Dadem, Nancin Y.; Genberg, Becky L.; Agbaji, Oche O.

2017-01-01

Background. Decentralization of care and treatment for HIV infection in Africa makes services available in local health facilities. Decentralization has been associated with improved retention and comparable or superior treatment outcomes, but patient experiences are not well understood. Methods. We conducted a qualitative study of patient experiences in decentralized HIV care in Plateau State, north central Nigeria. Five decentralized care sites in the Plateau State Decentralization Initiative were purposefully selected. Ninety-three patients and 16 providers at these sites participated in individual interviews and focus groups. Data collection activities were audio-recorded and transcribed. Transcripts were inductively content analyzed to derive descriptive categories representing patient experiences of decentralized care. Results. Patient participants in this study experienced the transition to decentralized care as a series of “trade-offs.” Advantages cited included saving time and money on travel to clinic visits, avoiding dangers on the road, and the “family-like atmosphere” found in some decentralized clinics. Disadvantages were loss of access to ancillary services, reduced opportunities for interaction with providers, and increased risk of disclosure. Participants preferred decentralized services overall. Conclusion. Difficulty and cost of travel remain a fundamental barrier to accessing HIV care outside urban centers, suggesting increased availability of community-based services will be enthusiastically received. PMID:28331636

Patient Experiences of Decentralized HIV Treatment and Care in Plateau State, North Central Nigeria: A Qualitative Study.

PubMed

Kolawole, Grace O; Gilbert, Hannah N; Dadem, Nancin Y; Genberg, Becky L; Agaba, Patricia A; Okonkwo, Prosper; Agbaji, Oche O; Ware, Norma C

2017-01-01

Background. Decentralization of care and treatment for HIV infection in Africa makes services available in local health facilities. Decentralization has been associated with improved retention and comparable or superior treatment outcomes, but patient experiences are not well understood. Methods. We conducted a qualitative study of patient experiences in decentralized HIV care in Plateau State, north central Nigeria. Five decentralized care sites in the Plateau State Decentralization Initiative were purposefully selected. Ninety-three patients and 16 providers at these sites participated in individual interviews and focus groups. Data collection activities were audio-recorded and transcribed. Transcripts were inductively content analyzed to derive descriptive categories representing patient experiences of decentralized care. Results. Patient participants in this study experienced the transition to decentralized care as a series of "trade-offs." Advantages cited included saving time and money on travel to clinic visits, avoiding dangers on the road, and the "family-like atmosphere" found in some decentralized clinics. Disadvantages were loss of access to ancillary services, reduced opportunities for interaction with providers, and increased risk of disclosure. Participants preferred decentralized services overall. Conclusion. Difficulty and cost of travel remain a fundamental barrier to accessing HIV care outside urban centers, suggesting increased availability of community-based services will be enthusiastically received.

Decentralized session initiation protocol solution in ad hoc networks

NASA Astrophysics Data System (ADS)

Han, Lu; Jin, Zhigang; Shu, Yantai; Dong, Linfang

2006-10-01

With the fast development of ad hoc networks, SIP has attracted more and more attention in multimedia service. This paper proposes a new architecture to provide SIP service for ad hoc users, although there is no centralized SIP server deployed. In this solution, we provide the SIP service by the introduction of two nodes: Designated SIP Server (DS) and its Backup Server (BDS). The nodes of ad hoc network designate DS and BDS when they join the session nodes set and when some pre-defined events occur. A new sip message type called REGISTRAR is presented so nodes can send others REGISTRAR message to declare they want to be DS. According to the IP information taken in the message, an algorithm works like the election of DR and BDR in OSPF protocol is used to vote DS and BDS SIP servers. Naturally, the DS will be replaced by BDS when the DS is down for predicable or unpredictable reasons. To facilitate this, the DS should register to the BDS and transfer a backup of the SIP users' database. Considering the possibility DS or BDS may abruptly go down, a special policy is given. When there is no DS and BDS, a new election procedure is triggered just like the startup phase. The paper also describes how SIP works normally in the decentralized model as well as the evaluation of its performance. All sessions based on SIP in ad hoc such as DS voting have been tested in the real experiments within a 500m*500m square area where about 30 random nodes are placed.

A new analytical framework of 'continuum of prevention and care' to maximize HIV case detection and retention in care in Vietnam

PubMed Central

2012-01-01

Background The global initiative ‘Treatment 2.0’ calls for expanding the evidence base of optimal HIV service delivery models to maximize HIV case detection and retention in care. However limited systematic assessment has been conducted in countries with concentrated HIV epidemic. We aimed to assess HIV service availability and service connectedness in Vietnam. Methods We developed a new analytical framework of the continuum of prevention and care (COPC). Using the framework, we examined HIV service delivery in Vietnam. Specifically, we analyzed HIV service availability including geographical distribution and decentralization and service connectedness across multiple services and dimensions. We then identified system-related strengths and constraints in improving HIV case detection and retention in care. This was accomplished by reviewing related published and unpublished documents including existing service delivery data. Results Identified strengths included: decentralized HIV outpatient clinics that offer comprehensive care at the district level particularly in high HIV burden provinces; functional chronic care management for antiretroviral treatment (ART) with the involvement of people living with HIV and the links to community- and home-based care; HIV testing and counseling integrated into tuberculosis and antenatal care services in districts supported by donor-funded projects, and extensive peer outreach networks that reduce barriers for the most-at-risk populations to access services. Constraints included: fragmented local coordination mechanisms for HIV-related health services; lack of systems to monitor the expansion of HIV outpatient clinics that offer comprehensive care; underdevelopment of pre-ART care; insufficient linkage from HIV testing and counseling to pre-ART care; inadequate access to HIV-related services in districts not supported by donor-funded projects particularly in middle and low burden provinces and in mountainous remote areas; and no systematic monitoring of referral services. Conclusions Our COPC analytical framework was instrumental in identifying system-related strengths and constraints that contribute to HIV case detection and retention in care. The national HIV program plans to strengthen provincial programming by re-defining various service linkages and accelerate the transition from project-based approach to integrated service delivery in line with the ‘Treatment 2.0’ initiative. PMID:23272730

A new analytical framework of 'continuum of prevention and care' to maximize HIV case detection and retention in care in Vietnam.

PubMed

Fujita, Masami; Poudel, Krishna C; Do, Thi Nhan; Bui, Duc Duong; Nguyen, Van Kinh; Green, Kimberly; Nguyen, Thi Minh Thu; Kato, Masaya; Jacka, David; Cao, Thi Thanh Thuy; Nguyen, Thanh Long; Jimba, Masamine

2012-12-29

The global initiative 'Treatment 2.0' calls for expanding the evidence base of optimal HIV service delivery models to maximize HIV case detection and retention in care. However limited systematic assessment has been conducted in countries with concentrated HIV epidemic. We aimed to assess HIV service availability and service connectedness in Vietnam. We developed a new analytical framework of the continuum of prevention and care (COPC). Using the framework, we examined HIV service delivery in Vietnam. Specifically, we analyzed HIV service availability including geographical distribution and decentralization and service connectedness across multiple services and dimensions. We then identified system-related strengths and constraints in improving HIV case detection and retention in care. This was accomplished by reviewing related published and unpublished documents including existing service delivery data. Identified strengths included: decentralized HIV outpatient clinics that offer comprehensive care at the district level particularly in high HIV burden provinces; functional chronic care management for antiretroviral treatment (ART) with the involvement of people living with HIV and the links to community- and home-based care; HIV testing and counseling integrated into tuberculosis and antenatal care services in districts supported by donor-funded projects, and extensive peer outreach networks that reduce barriers for the most-at-risk populations to access services. Constraints included: fragmented local coordination mechanisms for HIV-related health services; lack of systems to monitor the expansion of HIV outpatient clinics that offer comprehensive care; underdevelopment of pre-ART care; insufficient linkage from HIV testing and counseling to pre-ART care; inadequate access to HIV-related services in districts not supported by donor-funded projects particularly in middle and low burden provinces and in mountainous remote areas; and no systematic monitoring of referral services. Our COPC analytical framework was instrumental in identifying system-related strengths and constraints that contribute to HIV case detection and retention in care. The national HIV program plans to strengthen provincial programming by re-defining various service linkages and accelerate the transition from project-based approach to integrated service delivery in line with the 'Treatment 2.0' initiative.

Evolutionary dynamics of the traveler's dilemma and minimum-effort coordination games on complex networks.

PubMed

Iyer, Swami; Killingback, Timothy

2014-10-01

The traveler's dilemma game and the minimum-effort coordination game are social dilemmas that have received significant attention resulting from the fact that the predictions of classical game theory are inconsistent with the results found when the games are studied experimentally. Moreover, both the traveler's dilemma and the minimum-effort coordination games have potentially important applications in evolutionary biology. Interestingly, standard deterministic evolutionary game theory, as represented by the replicator dynamics in a well-mixed population, is also inadequate to account for the behavior observed in these games. Here we study the evolutionary dynamics of both these games in populations with interaction patterns described by a variety of complex network topologies. We investigate the evolutionary dynamics of these games through agent-based simulations on both model and empirical networks. In particular, we study the effects of network clustering and assortativity on the evolutionary dynamics of both games. In general, we show that the evolutionary behavior of the traveler's dilemma and minimum-effort coordination games on complex networks is in good agreement with that observed experimentally. Thus, formulating the traveler's dilemma and the minimum-effort coordination games on complex networks neatly resolves the paradoxical aspects of these games.

Evolutionary dynamics of the traveler's dilemma and minimum-effort coordination games on complex networks

NASA Astrophysics Data System (ADS)

Iyer, Swami; Killingback, Timothy

2014-10-01

The traveler's dilemma game and the minimum-effort coordination game are social dilemmas that have received significant attention resulting from the fact that the predictions of classical game theory are inconsistent with the results found when the games are studied experimentally. Moreover, both the traveler's dilemma and the minimum-effort coordination games have potentially important applications in evolutionary biology. Interestingly, standard deterministic evolutionary game theory, as represented by the replicator dynamics in a well-mixed population, is also inadequate to account for the behavior observed in these games. Here we study the evolutionary dynamics of both these games in populations with interaction patterns described by a variety of complex network topologies. We investigate the evolutionary dynamics of these games through agent-based simulations on both model and empirical networks. In particular, we study the effects of network clustering and assortativity on the evolutionary dynamics of both games. In general, we show that the evolutionary behavior of the traveler's dilemma and minimum-effort coordination games on complex networks is in good agreement with that observed experimentally. Thus, formulating the traveler's dilemma and the minimum-effort coordination games on complex networks neatly resolves the paradoxical aspects of these games.

Game-Theoretical Design of an Adaptive Distributed Dissemination Protocol for VANETs.

PubMed

Iza-Paredes, Cristhian; Mezher, Ahmad Mohamad; Aguilar Igartua, Mónica; Forné, Jordi

2018-01-19

Road safety applications envisaged for Vehicular Ad Hoc Networks (VANETs) depend largely on the dissemination of warning messages to deliver information to concerned vehicles. The intended applications, as well as some inherent VANET characteristics, make data dissemination an essential service and a challenging task in this kind of networks. This work lays out a decentralized stochastic solution for the data dissemination problem through two game-theoretical mechanisms. Given the non-stationarity induced by a highly dynamic topology, diverse network densities, and intermittent connectivity, a solution for the formulated game requires an adaptive procedure able to exploit the environment changes. Extensive simulations reveal that our proposal excels in terms of number of transmissions, lower end-to-end delay and reduced overhead while maintaining high delivery ratio, compared to other proposals.

Game-Theoretical Design of an Adaptive Distributed Dissemination Protocol for VANETs

PubMed Central

Mezher, Ahmad Mohamad; Aguilar Igartua, Mónica

2018-01-01

Road safety applications envisaged for Vehicular Ad Hoc Networks (VANETs) depend largely on the dissemination of warning messages to deliver information to concerned vehicles. The intended applications, as well as some inherent VANET characteristics, make data dissemination an essential service and a challenging task in this kind of networks. This work lays out a decentralized stochastic solution for the data dissemination problem through two game-theoretical mechanisms. Given the non-stationarity induced by a highly dynamic topology, diverse network densities, and intermittent connectivity, a solution for the formulated game requires an adaptive procedure able to exploit the environment changes. Extensive simulations reveal that our proposal excels in terms of number of transmissions, lower end-to-end delay and reduced overhead while maintaining high delivery ratio, compared to other proposals. PMID:29351255

Multirate control with incomplete information over Profibus-DP network

NASA Astrophysics Data System (ADS)

Salt, J.; Casanova, V.; Cuenca, A.; Pizá, R.

2014-07-01

When a process field bus-decentralized peripherals (Profibus-DP) network is used in an industrial environment, a deterministic behaviour is usually claimed. However, due to some concerns such as bandwidth limitations, lack of synchronisation among different clocks and existence of time-varying delays, a more complex problem must be faced. This problem implies the transmission of irregular and, even, random sequences of incomplete information. The main consequence of this issue is the appearance of different sampling periods at different network devices. In this paper, this aspect is checked by means of a detailed Profibus-DP timescale study. In addition, in order to deal with the different periods, a delay-dependent dual-rate proportional-integral-derivative control is introduced. Stability for the proposed control system is analysed in terms of linear matrix inequalities.

Evolution versus "intelligent design": comparing the topology of protein-protein interaction networks to the Internet.

PubMed

Yang, Q; Siganos, G; Faloutsos, M; Lonardi, S

2006-01-01

Recent research efforts have made available genome-wide, high-throughput protein-protein interaction (PPI) maps for several model organisms. This has enabled the systematic analysis of PPI networks, which has become one of the primary challenges for the system biology community. In this study, we attempt to understand better the topological structure of PPI networks by comparing them against man-made communication networks, and more specifically, the Internet. Our comparative study is based on a comprehensive set of graph metrics. Our results exhibit an interesting dichotomy. On the one hand, both networks share several macroscopic properties such as scale-free and small-world properties. On the other hand, the two networks exhibit significant topological differences, such as the cliqueishness of the highest degree nodes. We attribute these differences to the distinct design principles and constraints that both networks are assumed to satisfy. We speculate that the evolutionary constraints that favor the survivability and diversification are behind the building process of PPI networks, whereas the leading force in shaping the Internet topology is a decentralized optimization process geared towards efficient node communication.

Intra- and intersegmental influences among central pattern generating networks in the walking system of the stick insect.

PubMed

Mantziaris, Charalampos; Bockemühl, Till; Holmes, Philip; Borgmann, Anke; Daun, Silvia; Büschges, Ansgar

2017-10-01

To efficiently move around, animals need to coordinate their limbs. Proper, context-dependent coupling among the neural networks underlying leg movement is necessary for generating intersegmental coordination. In the slow-walking stick insect, local sensory information is very important for shaping coordination. However, central coupling mechanisms among segmental central pattern generators (CPGs) may also contribute to this. Here, we analyzed the interactions between contralateral networks that drive the depressor trochanteris muscle of the legs in both isolated and interconnected deafferented thoracic ganglia of the stick insect on application of pilocarpine, a muscarinic acetylcholine receptor agonist. Our results show that depressor CPG activity is only weakly coupled between all segments. Intrasegmental phase relationships differ between the three isolated ganglia, and they are modified and stabilized when ganglia are interconnected. However, the coordination patterns that emerge do not resemble those observed during walking. Our findings are in line with recent studies and highlight the influence of sensory input on coordination in slowly walking insects. Finally, as a direct interaction between depressor CPG networks and contralateral motoneurons could not be observed, we hypothesize that coupling is based on interactions at the level of CPG interneurons. NEW & NOTEWORTHY Maintaining functional interleg coordination is vitally important as animals locomote through changing environments. The relative importance of central mechanisms vs. sensory feedback in this process is not well understood. We analyzed coordination among the neural networks generating leg movements in stick insect preparations lacking phasic sensory feedback. Under these conditions, the networks governing different legs were only weakly coupled. In stick insect, central connections alone are thus insufficient to produce the leg coordination observed behaviorally. Copyright © 2017 the American Physiological Society.

Contribution of Optical Zone Decentration and Pupil Dilation on the Change of Optical Quality After Myopic Photorefractive Keratectomy in a Cat Model

PubMed Central

Bühren, Jens; Yoon, Geunyoung; MacRae, Scott; Huxlin, Krystel

2010-01-01

PURPOSE To simulate the simultaneous contribution of optical zone decentration and pupil dilation on retinal image quality using wavefront error data from a myopic photorefractive keratectomy (PRK) cat model. METHODS Wavefront error differences were obtained from five cat eyes 19±7 weeks (range: 12 to 24 weeks) after spherical myopic PRK for −6.00 diopters (D) (three eyes) and −10.00 D (two eyes). A computer model was used to simulate decentration of a 6-mm sub-aperture relative to the measured wavefront error difference. Changes in image quality (visual Strehl ratio based on the optical transfer function [VSOTF]) were computed for simulated decentrations from 0 to 1500 μm over pupil diameters of 3.5 to 6.0 mm in 0.5-mm steps. For each eye, a bivariate regression model was applied to calculate the simultaneous contribution of pupil dilation and decentration on the pre- to postoperative change of the log VSOTF. RESULTS Pupil diameter and decentration explained up to 95% of the variance of VSOTF change (adjusted R2=0.95). Pupil diameter had a higher impact on VSOTF (median β=−0.88, P<.001) than decentration (median β= −0.45, P<.001). If decentration-induced lower order aberrations were corrected, the impact of decentration further decreased (β= −0.26) compared to the influence of pupil dilation (β= −0.95). CONCLUSIONS Both pupil dilation and decentration of the optical zone affected the change of retinal image quality (VSOTF) after myopic PRK with decentration exerting a lower impact on VSOTF change. Thus, under physiological conditions pupil dilation is likely to have more effect on VSOTF change after PRK than optical zone decentration. PMID:20229950

Contribution of optical zone decentration and pupil dilation on the change of optical quality after myopic photorefractive keratectomy in a cat model.

PubMed

Bühren, Jens; Yoon, Geunyoung; MacRae, Scott; Huxlin, Krystel

2010-03-01

To simulate the simultaneous contribution of optical zone decentration and pupil dilation on retinal image quality using wavefront error data from a myopic photorefractive keratectomy (PRK) cat model. Wavefront error differences were obtained from five cat eyes 19+/-7 weeks (range: 12 to 24 weeks) after spherical myopic PRK for -6.00 diopters (D) (three eyes) and -10.00 D (two eyes). A computer model was used to simulate decentration of a 6-mm sub-aperture relative to the measured wavefront error difference. Changes in image quality (visual Strehl ratio based on the optical transfer function [VSOTF]) were computed for simulated decentrations from 0 to 1500 mum over pupil diameters of 3.5 to 6.0 mm in 0.5-mm steps. For each eye, a bivariate regression model was applied to calculate the simultaneous contribution of pupil dilation and decentration on the pre- to postoperative change of the log VSOTF. Pupil diameter and decentration explained up to 95% of the variance of VSOTF change (adjusted R(2)=0.95). Pupil diameter had a higher impact on VSOTF (median beta=-0.88, P<.001) than decentration (median beta=-0.45, P<.001). If decentration-induced lower order aberrations were corrected, the impact of decentration further decreased (beta=-0.26) compared to the influence of pupil dilation (beta=-0.95). Both pupil dilation and decentration of the optical zone affected the change of retinal image quality (VSOTF) after myopic PRK with decentration exerting a lower impact on VSOTF change. Thus, under physiological conditions pupil dilation is likely to have more effect on VSOTF change after PRK than optical zone decentration. Copyright 2010, SLACK Incorporated.

Fixed Point Learning Based Intelligent Traffic Control System

NASA Astrophysics Data System (ADS)

Zongyao, Wang; Cong, Sui; Cheng, Shao

2017-10-01

Fixed point learning has become an important tool to analyse large scale distributed system such as urban traffic network. This paper presents a fixed point learning based intelligence traffic network control system. The system applies convergence property of fixed point theorem to optimize the traffic flow density. The intelligence traffic control system achieves maximum road resources usage by averaging traffic flow density among the traffic network. The intelligence traffic network control system is built based on decentralized structure and intelligence cooperation. No central control is needed to manage the system. The proposed system is simple, effective and feasible for practical use. The performance of the system is tested via theoretical proof and simulations. The results demonstrate that the system can effectively solve the traffic congestion problem and increase the vehicles average speed. It also proves that the system is flexible, reliable and feasible for practical use.

MAC layer security issues in wireless mesh networks

NASA Astrophysics Data System (ADS)

Reddy, K. Ganesh; Thilagam, P. Santhi

2016-03-01

Wireless Mesh Networks (WMNs) have emerged as a promising technology for a broad range of applications due to their self-organizing, self-configuring and self-healing capability, in addition to their low cost and easy maintenance. Securing WMNs is more challenging and complex issue due to their inherent characteristics such as shared wireless medium, multi-hop and inter-network communication, highly dynamic network topology and decentralized architecture. These vulnerable features expose the WMNs to several types of attacks in MAC layer. The existing MAC layer standards and implementations are inadequate to secure these features and fail to provide comprehensive security solutions to protect both backbone and client mesh. Hence, there is a need for developing efficient, scalable and integrated security solutions for WMNs. In this paper, we classify the MAC layer attacks and analyze the existing countermeasures. Based on attacks classification and countermeasures analysis, we derive the research directions to enhance the MAC layer security for WMNs.

Rethinking Partnerships on a Decentralized Campus

ERIC Educational Resources Information Center

Dufault, Katie H.

2017-01-01

Decentralization is an effective approach for structuring campus learning and success centers. McShane & Von Glinow (2007) describe decentralization as "an organizational model where decision authority and power are dispersed among units rather than held by a single small group of administrators" (p. 237). A decentralized structure…

Origin of hyperbolicity in brain-to-brain coordination networks

NASA Astrophysics Data System (ADS)

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 < 1 and can be attributed to the topology of the subgraph formed around the cross-brains linking channels. We identify these subgraphs in each studied two-brain network and decompose their structure into simple geometric descriptors (triangles, tetrahedra and cliques of higher orders) that contribute to hyperbolicity. Considering topologies that exceed two separate brain networks as a measure of coordination synergy between the brains, we identify different 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.

Back to basics: does decentralization improve health system performance? Evidence from Ceara in north-east Brazil.

PubMed Central

Atkinson, Sarah; Haran, Dave

2004-01-01

OBJECTIVE: To examine whether decentralization has improved health system performance in the State of Ceara, north-east Brazil. METHODS: Ceara is strongly committed to decentralization. A survey across 45 local (municipio) health systems collected data on performance and formal organization, including decentralization, informal management and local political culture. The indicators for informal management and local political culture were based on prior ethnographic research. Data were analysed using analysis of variance, Duncan's post-hoc test and multiple regression. FINDINGS: Decentralization was associated with improved performance, but only for 5 of our 22 performance indicators. Moreover, in the multiple regression, decentralization explained the variance in only one performance indicator; indicators for informal management and political culture appeared to be more important influences. However, some indicators for informal management were themselves associated with decentralization but not any of the political culture indicators. CONCLUSION: Good management practices in the study led to decentralized local health systems rather than vice versa. Any apparent association between decentralization and performance seems to be an artefact of the informal management, and the wider political culture in which a local health system is embedded strongly influences the performance of local health systems. PMID:15640917

Comparative Perspectives on Educational Decentralization: An Exercise in Contradiction?

ERIC Educational Resources Information Center

Weiler, Hans N.

1990-01-01

It is argued that policies decentralizing the governance of educational systems, although appealing in the abstract, tend to be fundamentally ambivalent and in conflict with powerful forces favoring centralization. Tensions surrounding the issue of decentralization are discussed, with emphasis on the relationship between decentralization and…

Does Decentralization Improve Health System Performance and Outcomes in Low- and Middle-Income Countries? A Systematic Review of Evidence From Quantitative Studies.

PubMed

Dwicaksono, Adenantera; Fox, Ashley M

2018-06-01

Policy Points: For more than 3 decades, international development agencies have advocated health system decentralization to improve health system performance in low- and middle-income countries. We found little rigorous evidence documenting the impact of decentralization processes on health system performance or outcomes in part due to challenges in measuring such far-reaching and multifaceted system-level changes. We propose a renewed research agenda that focuses on discrete definitions of decentralization and how institutional factors and mechanisms affect health system performance and outcomes within the general context of decentralized governance structures. Despite the widespread adoption of decentralization reforms as a means to improve public service delivery in developing countries since the 1980s, empirical evidence of the role of decentralization on health system improvement is still limited and inconclusive. This study reviewed studies published from 2000 to 2016 with adequate research designs to identify evidence on whether and how decentralization processes have impacted health systems. We conducted a systematic review of peer-reviewed journal articles from the public health and social science literature. We searched for articles within 9 databases using predefined search terms reflecting decentralization and health system constructs. Inclusion criteria were original research articles, low- and middle-income country settings, quantifiable outcome measures, and study designs that use comparisons or statistical adjustments. We excluded studies in high-income country settings and/or published in a non-English language. Sixteen studies met our prespecified inclusion and exclusion criteria and were grouped based on outcomes measured: health system inputs (n = 3), performance (n = 7), and health outcomes (n = 7). Numerous studies addressing conceptual issues related to decentralization but without any attempt at empirical estimation were excluded. Overall, we found mixed results regarding the effects of decentralization on health system indicators with seemingly beneficial effects on health system performance and health outcomes. Only 10 studies were considered to have relatively low risks of bias. This study reveals the limited empirical knowledge of the impact of decentralization on health system performance. Mixed empirical findings on the role of decentralization on health system performance and outcomes highlight the complexity of decentralization processes and their systemwide effects. Thus, we propose a renewed research agenda that focuses on discrete definitions of decentralization and how institutional factors and mechanisms affect health system performance and outcomes within the general context of decentralized governance structures. © 2018 Milbank Memorial Fund.

GVE-Based Dynamics and Control for Formation Flying Spacecraft

NASA Technical Reports Server (NTRS)

Breger, Louis; How, Jonathan P.

2004-01-01

Formation flying is an enabling technology for many future space missions. This paper presents extensions to the equations of relative motion expressed in Keplerian orbital elements, including new initialization techniques for general formation configurations. A new linear time-varying form of the equations of relative motion is developed from Gauss Variational Equations and used in a model predictive controller. The linearizing assumptions for these equations are shown to be consistent with typical formation flying scenarios. Several linear, convex initialization techniques are presented, as well as a general, decentralized method for coordinating a tetrahedral formation using differential orbital elements. Control methods are validated using a commercial numerical propagator.

MaGate Simulator: A Simulation Environment for a Decentralized Grid Scheduler

NASA Astrophysics Data System (ADS)

Huang, Ye; Brocco, Amos; Courant, Michele; Hirsbrunner, Beat; Kuonen, Pierre

This paper presents a simulator for of a decentralized modular grid scheduler named MaGate. MaGate’s design emphasizes scheduler interoperability by providing intelligent scheduling serving the grid community as a whole. Each MaGate scheduler instance is able to deal with dynamic scheduling conditions, with continuously arriving grid jobs. Received jobs are either allocated on local resources, or delegated to other MaGates for remote execution. The proposed MaGate simulator is based on GridSim toolkit and Alea simulator, and abstracts the features and behaviors of complex fundamental grid elements, such as grid jobs, grid resources, and grid users. Simulation of scheduling tasks is supported by a grid network overlay simulator executing distributed ant-based swarm intelligence algorithms to provide services such as group communication and resource discovery. For evaluation, a comparison of behaviors of different collaborative policies among a community of MaGates is provided. Results support the use of the proposed approach as a functional ready grid scheduler simulator.

Support for School-to-School Networks: How Networking Teachers Perceive Support Activities of a Local Coordinating Agency

ERIC Educational Resources Information Center

Sartory, Katharina; Jungermann, Anja-Kristin; Järvinen, Hanna

2017-01-01

External support by a local coordinating agency facilitates the work of school-to-school networks. This study provides an innovative theoretical framework to analyse how support provided by local education offices for school-to-school networks is perceived by the participating teachers. Based on a quantitative survey and qualitative interview data…

Theory and applications survey of decentralized control methods

NASA Technical Reports Server (NTRS)

Athans, M.

1975-01-01

A nonmathematical overview is presented of trends in the general area of decentralized control strategies which are suitable for hierarchical systems. Advances in decentralized system theory are closely related to advances in the so-called stochastic control problem with nonclassical information pattern. The basic assumptions and mathematical tools pertaining to the classical stochastic control problem are outlined. Particular attention is devoted to pitfalls in the mathematical problem formulation for decentralized control. Major conclusions are that any purely deterministic approach to multilevel hierarchical dynamic systems is unlikely to lead to realistic theories or designs, that the flow of measurements and decisions in a decentralized system should not be instantaneous and error-free, and that delays in information exchange in a decentralized system lead to reasonable approaches to decentralized control. A mathematically precise notion of aggregating information is not yet available.

Distributed Coordination for Optimal Energy Generation and Distribution in Cyber-Physical Energy Networks.

PubMed

Ahn, Hyo-Sung; Kim, Byeong-Yeon; Lim, Young-Hun; Lee, Byung-Hun; Oh, Kwang-Kyo

2018-03-01

This paper proposes three coordination laws for optimal energy generation and distribution in energy network, which is composed of physical flow layer and cyber communication layer. The physical energy flows through the physical layer; but all the energies are coordinated to generate and flow by distributed coordination algorithms on the basis of communication information. First, distributed energy generation and energy distribution laws are proposed in a decoupled manner without considering the interactive characteristics between the energy generation and energy distribution. Second, a joint coordination law to treat the energy generation and energy distribution in a coupled manner taking account of the interactive characteristics is designed. Third, to handle over- or less-energy generation cases, an energy distribution law for networks with batteries is designed. The coordination laws proposed in this paper are fully distributed in the sense that they are decided optimally only using relative information among neighboring nodes. Through numerical simulations, the validity of the proposed distributed coordination laws is illustrated.

The National Response System: The Need to Leverage Networks and Knowledge

DTIC Science & Technology

2006-03-01

military organizations engaged a battle against the asymmetric threat of terrorism. In 1996 , John Arquilla and David Ronfeldt coined the use of the term...16 John Arquilla and others, The Advent of Netwar (Santa Monica: RAND, 1996 ), 5, http://www.rand.org/publications/MR/MR789/ [Accessed January 12...Advent of Netwar (Santa Monica: RAND, 1996 ), 82, http://www.rand.org/publications/MR/MR789/. 20 Richard M. Gomez, "Centralized Command - Decentralized

Harvard Catalyst | The Clinical Translational Science Center IND/IDE Consult Service: providing an IND/IDE consult service in a decentralized network of academic healthcare centers.

PubMed

Kim, Min J; Winkler, Sabune J; Bierer, Barbara E; Wolf, Delia

2014-04-01

The Food and Drug Administration (FDA) regulations require sponsors of clinical investigations involving an investigational drug or device to submit an Investigational New Drug (IND) or Investigational Device Exemption (IDE) application. Strict adherence to applicable regulations is vital to the success of clinical research. Unlike most major pharmaceutical sponsors, investigator sponsors often do not fully appreciate their regulatory obligations nor have resources to ensure compliance. As a result they can place themselves and their institutions at risk. Nevertheless, investigator-initiated clinical trials are vital to the further development of innovative drugs, biologics, and medical devices. The IND/IDE Subcommittee under the Regulatory Knowledge and Support Program at Harvard Catalyst, The Harvard Clinical and Translational Science Center worked in collaboration with Harvard and Harvard affiliated institutions to create and launch an IND/IDE Consult Service in a decentralized network of collaborating Academic Healthcare Centers (AHC). The IND/IDE Consult Service offers expertise, resources, and shared experiences to assist sponsor-investigators and IRBs in meeting regulatory requirements for conducting and reviewing investigator-initiated IND/IDE studies. The scope of the services provided by the Harvard Catalyst IND/IDE Consult Service are described, including the specifics of the service, lessons learned, and challenges faced, in a scalable model that builds inter-institutional capacity. © 2014 Wiley Periodicals, Inc.

Harvard Catalyst | The Clinical Translational Science Center IND/IDE Consult Service: Providing an IND/IDE Consult Service in a Decentralized Network of Academic Healthcare Centers

PubMed Central

Winkler, Sabune J.; Bierer, Barbara E.; Wolf, Delia

2014-01-01

Abstract The Food and Drug Administration (FDA) regulations require sponsors of clinical investigations involving an investigational drug or device to submit an Investigational New Drug (IND) or Investigational Device Exemption (IDE) application. Strict adherence to applicable regulations is vital to the success of clinical research. Unlike most major pharmaceutical sponsors, investigator sponsors often do not fully appreciate their regulatory obligations nor have resources to ensure compliance. As a result they can place themselves and their institutions at risk. Nevertheless, investigator‐initiated clinical trials are vital to the further development of innovative drugs, biologics, and medical devices. The IND/IDE Subcommittee under the Regulatory Knowledge and Support Program at Harvard Catalyst, The Harvard Clinical and Translational Science Center worked in collaboration with Harvard and Harvard affiliated institutions to create and launch an IND/IDE Consult Service in a decentralized network of collaborating Academic Healthcare Centers (AHC). The IND/IDE Consult Service offers expertise, resources, and shared experiences to assist sponsor‐investigators and IRBs in meeting regulatory requirements for conducting and reviewing investigator‐initiated IND/IDE studies. The scope of the services provided by the Harvard Catalyst IND/IDE Consult Service are described, including the specifics of the service, lessons learned, and challenges faced, in a scalable model that builds inter‐institutional capacity. PMID:24455986

CSR: Constrained Selfish Routing in Ad-Hoc Networks

NASA Astrophysics Data System (ADS)

Bassem, Christine; Bestavros, Azer

Routing protocols for ad-hoc networks assume that the nodes forming the network are either under a single authority, or else that they would be altruistically forwarding data for other nodes with no expectation of a return. These assumptions are unrealistic since in ad-hoc networks, nodes are likely to be autonomous and rational (selfish), and thus unwilling to help unless they have an incentive to do so. Providing such incentives is an important aspect that should be considered when designing ad-hoc routing protocols. In this paper, we propose a dynamic, decentralized routing protocol for ad-hoc networks that provides incentives in the form of payments to intermediate nodes used to forward data for others. In our Constrained Selfish Routing (CSR) protocol, game-theoretic approaches are used to calculate payments (incentives) that ensure both the truthfulness of participating nodes and the fairness of the CSR protocol. We show through simulations that CSR is an energy efficient protocol and that it provides lower communication overhead in the best and average cases compared to existing approaches.

Algorithms for Lightweight Key Exchange.

PubMed

Alvarez, Rafael; Caballero-Gil, Cándido; Santonja, Juan; Zamora, Antonio

2017-06-27

Public-key cryptography is too slow for general purpose encryption, with most applications limiting its use as much as possible. Some secure protocols, especially those that enable forward secrecy, make a much heavier use of public-key cryptography, increasing the demand for lightweight cryptosystems that can be implemented in low powered or mobile devices. This performance requirements are even more significant in critical infrastructure and emergency scenarios where peer-to-peer networks are deployed for increased availability and resiliency. We benchmark several public-key key-exchange algorithms, determining those that are better for the requirements of critical infrastructure and emergency applications and propose a security framework based on these algorithms and study its application to decentralized node or sensor networks.

Using the OCLC union listing component for a statewide health sciences union list of serials.

PubMed Central

Sutton, L S; Wolfgram, P A

1986-01-01

Union lists of serials are critical to the effective operation of interlibrary loan networks. The Michigan Health Sciences Libraries Association used the OCLC union list component to produce the Michigan Statewide Health Sciences Union List of Serials (MISHULS). MISHULS, which includes the serials holdings of ninety-three hospital health sciences libraries, is a subset of a statewide multi-type union list maintained on OCLC. The rationale for a statewide list and the criteria for choosing vendors are discussed. Typical costs are provided. Funding sources are identified and a unique approach to decentralized input is described. The benefits of resource sharing in a larger, multi-type library network are also explored. PMID:3708192

Using the OCLC union listing component for a statewide health sciences union list of serials.

PubMed

Sutton, L S; Wolfgram, P A

1986-04-01

Union lists of serials are critical to the effective operation of interlibrary loan networks. The Michigan Health Sciences Libraries Association used the OCLC union list component to produce the Michigan Statewide Health Sciences Union List of Serials (MISHULS). MISHULS, which includes the serials holdings of ninety-three hospital health sciences libraries, is a subset of a statewide multi-type union list maintained on OCLC. The rationale for a statewide list and the criteria for choosing vendors are discussed. Typical costs are provided. Funding sources are identified and a unique approach to decentralized input is described. The benefits of resource sharing in a larger, multi-type library network are also explored.

Educational Decentralization, Public Spending, and Social Justice in Nigeria

ERIC Educational Resources Information Center

Geo-Jaja, Macleans A.

2006-01-01

This study situates the process of educational decentralization in the narrower context of social justice. Its main object, however, is to analyze the implications of decentralization for strategies of equity and social justice in Nigeria. It starts from the premise that the early optimism that supported decentralization as an efficient and…

Optimal source coding, removable noise elimination, and natural coordinate system construction for general vector sources using replicator neural networks

NASA Astrophysics Data System (ADS)

Hecht-Nielsen, Robert

1997-04-01

A new universal one-chart smooth manifold model for vector information sources is introduced. Natural coordinates (a particular type of chart) for such data manifolds are then defined. Uniformly quantized natural coordinates form an optimal vector quantization code for a general vector source. Replicator neural networks (a specialized type of multilayer perceptron with three hidden layers) are the introduced. As properly configured examples of replicator networks approach minimum mean squared error (e.g., via training and architecture adjustment using randomly chosen vectors from the source), these networks automatically develop a mapping which, in the limit, produces natural coordinates for arbitrary source vectors. The new concept of removable noise (a noise model applicable to a wide variety of real-world noise processes) is then discussed. Replicator neural networks, when configured to approach minimum mean squared reconstruction error (e.g., via training and architecture adjustment on randomly chosen examples from a vector source, each with randomly chosen additive removable noise contamination), in the limit eliminate removable noise and produce natural coordinates for the data vector portions of the noise-corrupted source vectors. Consideration regarding selection of the dimension of a data manifold source model and the training/configuration of replicator neural networks are discussed.

A Systems Biology Approach to the Coordination of Defensive and Offensive Molecular Mechanisms in the Innate and Adaptive Host–Pathogen Interaction Networks

PubMed Central

Wu, Chia-Chou; Chen, Bor-Sen

2016-01-01

Infected zebrafish coordinates defensive and offensive molecular mechanisms in response to Candida albicans infections, and invasive C. albicans coordinates corresponding molecular mechanisms to interact with the host. However, knowledge of the ensuing infection-activated signaling networks in both host and pathogen and their interspecific crosstalk during the innate and adaptive phases of the infection processes remains incomplete. In the present study, dynamic network modeling, protein interaction databases, and dual transcriptome data from zebrafish and C. albicans during infection were used to infer infection-activated host–pathogen dynamic interaction networks. The consideration of host–pathogen dynamic interaction systems as innate and adaptive loops and subsequent comparisons of inferred innate and adaptive networks indicated previously unrecognized crosstalk between known pathways and suggested roles of immunological memory in the coordination of host defensive and offensive molecular mechanisms to achieve specific and powerful defense against pathogens. Moreover, pathogens enhance intraspecific crosstalk and abrogate host apoptosis to accommodate enhanced host defense mechanisms during the adaptive phase. Accordingly, links between physiological phenomena and changes in the coordination of defensive and offensive molecular mechanisms highlight the importance of host–pathogen molecular interaction networks, and consequent inferences of the host–pathogen relationship could be translated into biomedical applications. PMID:26881892

A Systems Biology Approach to the Coordination of Defensive and Offensive Molecular Mechanisms in the Innate and Adaptive Host-Pathogen Interaction Networks.

PubMed

Wu, Chia-Chou; Chen, Bor-Sen

2016-01-01

Infected zebrafish coordinates defensive and offensive molecular mechanisms in response to Candida albicans infections, and invasive C. albicans coordinates corresponding molecular mechanisms to interact with the host. However, knowledge of the ensuing infection-activated signaling networks in both host and pathogen and their interspecific crosstalk during the innate and adaptive phases of the infection processes remains incomplete. In the present study, dynamic network modeling, protein interaction databases, and dual transcriptome data from zebrafish and C. albicans during infection were used to infer infection-activated host-pathogen dynamic interaction networks. The consideration of host-pathogen dynamic interaction systems as innate and adaptive loops and subsequent comparisons of inferred innate and adaptive networks indicated previously unrecognized crosstalk between known pathways and suggested roles of immunological memory in the coordination of host defensive and offensive molecular mechanisms to achieve specific and powerful defense against pathogens. Moreover, pathogens enhance intraspecific crosstalk and abrogate host apoptosis to accommodate enhanced host defense mechanisms during the adaptive phase. Accordingly, links between physiological phenomena and changes in the coordination of defensive and offensive molecular mechanisms highlight the importance of host-pathogen molecular interaction networks, and consequent inferences of the host-pathogen relationship could be translated into biomedical applications.

Genotet: An Interactive Web-based Visual Exploration Framework to Support Validation of Gene Regulatory Networks.

PubMed

Yu, Bowen; Doraiswamy, Harish; Chen, Xi; Miraldi, Emily; Arrieta-Ortiz, Mario Luis; Hafemeister, Christoph; Madar, Aviv; Bonneau, Richard; Silva, Cláudio T

2014-12-01

Elucidation of transcriptional regulatory networks (TRNs) is a fundamental goal in biology, and one of the most important components of TRNs are transcription factors (TFs), proteins that specifically bind to gene promoter and enhancer regions to alter target gene expression patterns. Advances in genomic technologies as well as advances in computational biology have led to multiple large regulatory network models (directed networks) each with a large corpus of supporting data and gene-annotation. There are multiple possible biological motivations for exploring large regulatory network models, including: validating TF-target gene relationships, figuring out co-regulation patterns, and exploring the coordination of cell processes in response to changes in cell state or environment. Here we focus on queries aimed at validating regulatory network models, and on coordinating visualization of primary data and directed weighted gene regulatory networks. The large size of both the network models and the primary data can make such coordinated queries cumbersome with existing tools and, in particular, inhibits the sharing of results between collaborators. In this work, we develop and demonstrate a web-based framework for coordinating visualization and exploration of expression data (RNA-seq, microarray), network models and gene-binding data (ChIP-seq). Using specialized data structures and multiple coordinated views, we design an efficient querying model to support interactive analysis of the data. Finally, we show the effectiveness of our framework through case studies for the mouse immune system (a dataset focused on a subset of key cellular functions) and a model bacteria (a small genome with high data-completeness).

Bimanual Motor Coordination in Older Adults Is Associated with Increased Functional Brain Connectivity – A Graph-Theoretical Analysis

PubMed Central

Heitger, Marcus H.; Goble, Daniel J.; Dhollander, Thijs; Dupont, Patrick; Caeyenberghs, Karen; Leemans, Alexander; Sunaert, Stefan; Swinnen, Stephan P.

2013-01-01

In bimanual coordination, older and younger adults activate a common cerebral network but the elderly also have additional activation in a secondary network of brain areas to master task performance. It remains unclear whether the functional connectivity within these primary and secondary motor networks differs between the old and the young and whether task difficulty modulates connectivity. We applied graph-theoretical network analysis (GTNA) to task-driven fMRI data in 16 elderly and 16 young participants using a bimanual coordination task including in-phase and anti-phase flexion/extension wrist movements. Network nodes for the GTNA comprised task-relevant brain areas as defined by fMRI activation foci. The elderly matched the motor performance of the young but showed an increased functional connectivity in both networks across a wide range of connectivity metrics, i.e., higher mean connectivity degree, connection strength, network density and efficiency, together with shorter mean communication path length between the network nodes and also a lower betweenness centrality. More difficult movements showed an increased connectivity in both groups. The network connectivity of both groups had “small world” character. The present findings indicate (a) that bimanual coordination in the aging brain is associated with a higher functional connectivity even between areas also activated in young adults, independently from task difficulty, and (b) that adequate motor coordination in the context of task-driven bimanual control in older adults may not be solely due to additional neural recruitment but also to aging-related changes of functional relationships between brain regions. PMID:23637982

A neural networks-based hybrid routing protocol for wireless mesh networks.

PubMed

Kojić, Nenad; Reljin, Irini; Reljin, Branimir

2012-01-01

The networking infrastructure of wireless mesh networks (WMNs) is decentralized and relatively simple, but they can display reliable functioning performance while having good redundancy. WMNs provide Internet access for fixed and mobile wireless devices. Both in urban and rural areas they provide users with high-bandwidth networks over a specific coverage area. The main problems affecting these networks are changes in network topology and link quality. In order to provide regular functioning, the routing protocol has the main influence in WMN implementations. In this paper we suggest a new routing protocol for WMN, based on good results of a proactive and reactive routing protocol, and for that reason it can be classified as a hybrid routing protocol. The proposed solution should avoid flooding and creating the new routing metric. We suggest the use of artificial logic-i.e., neural networks (NNs). This protocol is based on mobile agent technologies controlled by a Hopfield neural network. In addition to this, our new routing metric is based on multicriteria optimization in order to minimize delay and blocking probability (rejected packets or their retransmission). The routing protocol observes real network parameters and real network environments. As a result of artificial logic intelligence, the proposed routing protocol should maximize usage of network resources and optimize network performance.

A Neural Networks-Based Hybrid Routing Protocol for Wireless Mesh Networks

PubMed Central

Kojić, Nenad; Reljin, Irini; Reljin, Branimir

2012-01-01

The networking infrastructure of wireless mesh networks (WMNs) is decentralized and relatively simple, but they can display reliable functioning performance while having good redundancy. WMNs provide Internet access for fixed and mobile wireless devices. Both in urban and rural areas they provide users with high-bandwidth networks over a specific coverage area. The main problems affecting these networks are changes in network topology and link quality. In order to provide regular functioning, the routing protocol has the main influence in WMN implementations. In this paper we suggest a new routing protocol for WMN, based on good results of a proactive and reactive routing protocol, and for that reason it can be classified as a hybrid routing protocol. The proposed solution should avoid flooding and creating the new routing metric. We suggest the use of artificial logic—i.e., neural networks (NNs). This protocol is based on mobile agent technologies controlled by a Hopfield neural network. In addition to this, our new routing metric is based on multicriteria optimization in order to minimize delay and blocking probability (rejected packets or their retransmission). The routing protocol observes real network parameters and real network environments. As a result of artificial logic intelligence, the proposed routing protocol should maximize usage of network resources and optimize network performance. PMID:22969360

Assessing the Network of Agencies in Local Communities that Promote Healthy Eating and Lifestyles among Populations with Limited Resources.

PubMed

An, Ruopeng; Khan, Naiman; Loehmer, Emily; McCaffrey, Jennifer

2017-03-01

We assessed the network of agencies in local communities that promote healthy eating and lifestyles among populations with limited resources. Network surveys were administered among 159 Illinois agencies identified as serving limited-resource audiences categorized into 8 types: K-12 schools, early childhood centers, emergency food providers, health-related agencies, social resource centers, low-income/subsidized housing complexes, continuing education organizations, and others. Network analysis was conducted to examine 4 network structures - communications, funding, cooperation, and collaboration networks between agencies within each county/county cluster. Agencies in a network were found to be loosely connected, indicated by low network density. Reporting accuracy might be of concern, indicated by low reciprocity. Agencies in a network are decentralized rather than centralized around a few influential agencies, indicated by low betweenness centrality. There is suggestive evidence regarding homophily in a network, indicated by some significant correlations within agencies of the same type. Agencies connected in one network are significantly more likely to be connected in all the other networks as well. Promoting healthy eating and lifestyles among populations with limited resources warrants strong partnership across agencies in communities. Network analysis serves as a useful tool to evaluate community partnerships and facilitate coalition building..

Decentralization: Why, How, and toward What Ends? Special Policy Report, No. 1. Policy Briefs Series.

ERIC Educational Resources Information Center

Stinnette, Lynn J.

Administrators are looking at decentralization as a solution to issues troubling schools, teachers, and students. The notion of decentralization is accompanied by two assumptions. First, decentralization will produce an improvement in education because classroom decision making will be more responsive to the specific needs of a school. Second, in…

Decentralized Planning for Autonomous Agents Cooperating in Complex Missions

DTIC Science & Technology

2010-09-01

Consensus - based decentralized auctions for robust task allocation ," IEEE Transactions on Robotics...Robotics, vol. 24, pp. 209-222, 2006. [44] H.-L. Choi, L. Brunet, and J. P. How, " Consensus - based decentralized auctions for robust task allocation ...2003. 123 [31] L. Brunet, " Consensus - Based Auctions for Decentralized Task Assignment," Master’s thesis, Dept.

The political economy of decentralization of health and social services in Canada.

PubMed

Tsalikis, G

1989-01-01

A trend to decentralization in Canada's 'welfare state' has received support from the Left and from the Right. Some social critics of the Left expect decentralization to result in holistic services adjusted to local needs. Others, moreover, feel we are in the dawn of a new epoch in which major economic transformations are to bring about, through new class alliances and conflict, decentralization of power and a better quality of life in communities. These assumptions and their theoretical pitfalls are discussed here following an historical overview of the centralization/decentralization issue in Canadian social policy. It is argued that recent proposals of decentralization are a continuation of reactionary tendencies to constrain social expenditures, but not a path to better quality of life.

The educational approach within Colombia's nutrition plan (PAN)

NASA Astrophysics Data System (ADS)

de Pizano, Julia Mejia

1980-03-01

With the knowledge that malnutrition affects the quality of life of an individual, the Colombian Government set up in 1976 a unique multi-sectorial plan (PAN), to combat the country's serious malnutrition. Government agencies and private industries in the sectors of production, distribution, health, sanitation, and education have coordinated their previously independent efforts. Among the interesting aspects are the coordination of sectors through work at various levels and through control of the budget, the limitation of bureaucracy, and the decentralization of decision-making. The ongoing attempts to overcome the difficulties encountered include making decisions in the face of inconclusive knowledge on what constitutes a well-balanced diet; combating the lack of knowledge of professionals about the environment of the poorest percentage of the population; and revising the traditional teaching method to make it more successful through a multi-media approach to assure wider coverage and more impact for the least cost, using materials such as games, puppets, posters and radio.

Regionalization Lessons from Denmark.

PubMed

Vrangbaek, Karsten

2016-01-01

Denmark is a small Northern European country with an extensive welfare state and a strong commitment to maintaining a universal healthcare system. Like the other countries in the Nordic region, Denmark has a long tradition of democratically governed local and regional governments with extensive responsibilities in organizing welfare state services. The Danish healthcare system has demonstrated an ability to increase productivity, while at the same time maintaining a high level of patient satisfaction. Ongoing reforms have contributed to these results, as well as a firm commitment to innovation and coordination. Regions and municipalities in Denmark are governed by directly elected democratic councils. The Danish case is thus an example of democratic decentralization, but within a framework of national coordination and fiscal control. In spite of the difference in size and historical traditions there are also many similarities between Canada and Denmark, particularly in terms of health and social policy goals and aspirations, and in terms of the commitment to a comprehensive, universal healthcare system. These similarities provide interesting opportunities for comparison.

Climate change governance, cooperation and self-organization

NASA Astrophysics Data System (ADS)

Pacheco, Jorge M.; Vasconcelos, Vítor V.; Santos, Francisco C.

2014-12-01

When attempting to avoid global warming, individuals often face a social dilemma in which, besides securing future benefits, it is also necessary to reduce the chances of future losses. In this manuscript, we introduce a simple approach to address this type of dilemmas, in which the risk of failure plays a central role in individual decisions. This model can be shown to capture some of the essential features discovered in recent key experiments, while allowing one to extend in non-trivial ways the experimental conditions to regions of more practical interest. Our results suggest that global coordination for a common good should be attempted by segmenting tasks in many small to medium sized groups, in which perception of risk is high and uncertainty in collective goals is minimized. Moreover, our results support the conclusion that sanctioning institutions may further enhance the chances of coordinating to tame the planet's climate, as long as they are implemented in a decentralized and polycentric manner.

Benefits and Challenges of Scaling Up Expansion of Marine Protected Area Networks in the Verde Island Passage, Central Philippines.

PubMed

Horigue, Vera; Pressey, Robert L; Mills, Morena; Brotánková, Jana; Cabral, Reniel; Andréfouët, Serge

2015-01-01

Locally-established marine protected areas (MPAs) have been proven to achieve local-scale fisheries and conservation objectives. However, since many of these MPAs were not designed to form ecologically-connected networks, their contributions to broader-scale goals such as complementarity and connectivity can be limited. In contrast, integrated networks of MPAs designed with systematic conservation planning are assumed to be more effective--ecologically, socially, and economically--than collections of locally-established MPAs. There is, however, little empirical evidence that clearly demonstrates the supposed advantages of systematic MPA networks. A key reason is the poor record of implementation of systematic plans attributable to lack of local buy-in. An intermediate scenario for the expansion of MPAs is scaling up of local decisions, whereby locally-driven MPA initiatives are coordinated through collaborative partnerships among local governments and their communities. Coordination has the potential to extend the benefits of individual MPAs and perhaps to approach the potential benefits offered by systematic MPA networks. We evaluated the benefits of scaling up local MPAs to form networks by simulating seven expansion scenarios for MPAs in the Verde Island Passage, central Philippines. The scenarios were: uncoordinated community-based establishment of MPAs; two scenarios reflecting different levels of coordinated MPA expansion through collaborative partnerships; and four scenarios guided by systematic conservation planning with different contexts for governance. For each scenario, we measured benefits through time in terms of achievement of objectives for representation of marine habitats. We found that: in any governance context, systematic networks were more efficient than non-systematic ones; systematic networks were more efficient in broader governance contexts; and, contrary to expectations but with caveats, the uncoordinated scenario was slightly more efficient than the coordinated scenarios. Overall, however, coordinated MPA networks have the potential to be more efficient than the uncoordinated ones, especially when coordinated planning uses systematic methods.

Benefits and Challenges of Scaling Up Expansion of Marine Protected Area Networks in the Verde Island Passage, Central Philippines

PubMed Central

Horigue, Vera; Pressey, Robert L.; Mills, Morena; Brotánková, Jana; Cabral, Reniel; Andréfouët, Serge

2015-01-01

Locally-established marine protected areas (MPAs) have been proven to achieve local-scale fisheries and conservation objectives. However, since many of these MPAs were not designed to form ecologically-connected networks, their contributions to broader-scale goals such as complementarity and connectivity can be limited. In contrast, integrated networks of MPAs designed with systematic conservation planning are assumed to be more effective—ecologically, socially, and economically—than collections of locally-established MPAs. There is, however, little empirical evidence that clearly demonstrates the supposed advantages of systematic MPA networks. A key reason is the poor record of implementation of systematic plans attributable to lack of local buy-in. An intermediate scenario for the expansion of MPAs is scaling up of local decisions, whereby locally-driven MPA initiatives are coordinated through collaborative partnerships among local governments and their communities. Coordination has the potential to extend the benefits of individual MPAs and perhaps to approach the potential benefits offered by systematic MPA networks. We evaluated the benefits of scaling up local MPAs to form networks by simulating seven expansion scenarios for MPAs in the Verde Island Passage, central Philippines. The scenarios were: uncoordinated community-based establishment of MPAs; two scenarios reflecting different levels of coordinated MPA expansion through collaborative partnerships; and four scenarios guided by systematic conservation planning with different contexts for governance. For each scenario, we measured benefits through time in terms of achievement of objectives for representation of marine habitats. We found that: in any governance context, systematic networks were more efficient than non-systematic ones; systematic networks were more efficient in broader governance contexts; and, contrary to expectations but with caveats, the uncoordinated scenario was slightly more efficient than the coordinated scenarios. Overall, however, coordinated MPA networks have the potential to be more efficient than the uncoordinated ones, especially when coordinated planning uses systematic methods. PMID:26288089

Decentralization of CD4 testing in resource-limited settings: 7 years of experience in six African countries.

PubMed

Marinucci, F; Medina-Moreno, S; Paterniti, A D; Wattleworth, M; Redfield, R R

2011-05-01

Improving access to CD4 testing in resource-limited settings can be achieved through both centralized and decentralized testing networks. Decentralized testing models are more suitable for countries where the HIV epidemic affects a large portion of rural populations. Timely access to accurate CD4 results is crucial at the primary level of the health system. For the past 7 years, the Institute of Human Virology of the University of Maryland School of Medicine has implemented a flexible and sustainable three-phase model: (1) site assessment and improvement, (2) appropriate technology selection with capacity building through practical training and laboratory mentoring, and (3) quality management system strengthening and monitoring, to support accessibility to reliable CD4 counting at the point of service. CD4 testing capacity was established in 122 of 229 (53%) laboratories supported in Nigeria, Uganda, Kenya, Zambia, Tanzania, and Rwanda. Among those in rural settings, 46% (69/151) had CD4 testing available at site level, with a functioning flow cytometer installed at 28% (8/29) and 50% (61/122) of level 1 and level 2 sites, respectively. To strengthen local capacity, a total of 1,152 laboratory technicians were trained through 188 training sessions provided both on-site and at central locations. The overall quality of CD4 total testing procedure was assessed at 76% (92/121) of the laboratories, with 25% (23/92), 34% (31/92), and 33% (30/92) of them reporting excellent, good, and satisfactory performance. Balancing country-specific factors with the location of the clinic, number of patients, and the expected workload, was crucial in adapting this flexible model for decentralizing CD4 testing. The close collaboration with local governments and private vendors was key to successfully expanding access to CD4 testing within the framework of HIV care and treatment programs and for the sustainability of medical laboratories in resource-limited settings. Copyright © 2011 International Society for Advancement of Cytometry.

Administrative Decentralization in School Systems and Its Effect on the Organization of Media Services. Atlanta Public Schools: A Case Study.

ERIC Educational Resources Information Center

Williams, R. David

This study reviews the literature on public school administration and on decentralization to establish the groundwork for an analysis of the administration of a decentralized school system and its media services, discusses some of the confusion in the centralization vs. decentralization debate, and presents a heuristic study of the administration…

Decentralization of Education: Why, When, What, and How? Fundamentals of Educational Planning Series, Number 64.

ERIC Educational Resources Information Center

Welsh, Thomas; McGinn, Noel F.

Decentralization is arguably one of the most important phenomena to come on to the educational planning agenda in the last 15 years. Why a country should decentralize its educational decision-making process and which decisions should be decentralized are two questions that many decision-makers raise. This booklet is intended to provide educational…

The tradeoff between centralized and decentralized health services: evidence from rural areas in Mexico.

PubMed

Vargas Bustamante, Arturo

2010-09-01

This study investigates the effectiveness of centralized and decentralized health care providers in rural Mexico. It compares provider performance since both centralized and decentralized providers co-exist in rural areas of the country. The data are drawn from the 2003 household survey of Oportunidades, a comprehensive study of rural families from seven states in Mexico. The analyses compare out-of-pocket health care expenditures and utilization of preventive care among rural households with access to either centralized or decentralized health care providers. This study benefits from differences in timing of health care decentralization and from a quasi-random distribution of providers. Results show that overall centralized providers perform better. Households served by this organization report less regressive out-of-pocket health care expenditures (32% lower), and observe higher utilization of preventive services (3.6% more). Decentralized providers that were devolved to state governments in the early 1980s observe a slightly better performance than providers that were decentralized in the mid-1990s. These findings are robust to decentralization timing, heterogeneity in per capita government health expenditures, state and health infrastructure effects, and other confounders. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

Decentralization of health care systems and health outcomes: Evidence from a natural experiment.

PubMed

Jiménez-Rubio, Dolores; García-Gómez, Pilar

2017-09-01

While many countries worldwide are shifting responsibilities for their health systems to local levels of government, there is to date insufficient evidence about the potential impact of these policy reforms. We estimate the impact of decentralization of the health services on infant and neonatal mortality using a natural experiment: the devolution of health care decision making powers to Spanish regions. The devolution was implemented gradually and asymmetrically over a twenty-year period (1981-2002). The order in which the regions were decentralized was driven by political factors and hence can be considered exogenous to health outcomes. In addition, we exploit the dynamic effect of decentralization of health services and allow for heterogeneous effects by the two main types of decentralization implemented across regions: full decentralization (political and fiscal powers) versus political decentralization only. Our difference in differences results based on a panel dataset for the 50 Spanish provinces over the period 1980 to 2010 show that the lasting benefit of decentralization accrues only to regions which enjoy almost full fiscal and political powers and which are also among the richest regions. Copyright © 2017 Elsevier Ltd. All rights reserved.

The snow system: A decentralized medical data processing system.

PubMed

Bellika, Johan Gustav; Henriksen, Torje Starbo; Yigzaw, Kassaye Yitbarek

2015-01-01

Systems for large-scale reuse of electronic health record data is claimed to have the potential to transform the current health care delivery system. In principle three alternative solutions for reuse exist: centralized, data warehouse, and decentralized solutions. This chapter focuses on the decentralized system alternative. Decentralized systems may be categorized into approaches that move data to enable computations or move computations to the where data is located to enable computations. We describe a system that moves computations to where the data is located. Only this kind of decentralized solution has the capabilities to become ideal systems for reuse as the decentralized alternative enables computation and reuse of electronic health record data without moving or exposing the information to outsiders. This chapter describes the Snow system, which is a decentralized medical data processing system, its components and how it has been used. It also describes the requirements this kind of systems need to support to become sustainable and successful in recruiting voluntary participation from health institutions.

A Modified Actor-Power-Accountability Framework (MAPAF) for analyzing decentralized forest governance: case study from Ethiopia.

PubMed

Mohammed, Abrar Juhar; Inoue, Makoto

2014-06-15

This paper posits a Modified Actor-Power-Accountability Framework (MAPAF) that makes three major improvements on the Actor-Power-Accountability Framework (APAF) developed by Agrawal and Ribot (1999). These improvements emphasize the nature of decentralized property rights, linking the outputs of decentralization with its outcomes and the inclusion of contextual factors. Applying MAPAF to analyze outputs and outcomes from two major decentralized forest policies in Ethiopia, i.e., delegation and devolution, has demonstrated the following strengths of the framework. First, by incorporating vital bundles of property rights into APAF, MAPAF creates a common ground for exploring and comparing the extent of democratization achieved by different decentralizing reforms. Second, the inclusion of social and environmental outcomes in MAPAF makes it possible to link the output of decentralization with local level outcomes. Finally, the addition of contextual factors enhances MAPAF's explanatory power by providing room for investigating exogenous factors other than democratization that contribute to the outcomes of decentralization reforms. Copyright © 2014 Elsevier Ltd. All rights reserved.

Soft edges--organizational structure in dental education.

PubMed

Chambers, D W

1995-03-01

There is no one best organizational structure for dental schools or for their major subunits. The classical alternatives of functional and divisional organization are discussed in light of the rule that follows function, and the advantages and disadvantages of each are presented. Newer models--decentralization, matrix, and heterarchy--show how features of functional and divisional structure can be blended. Virtual organizations, systems theory, and networks are also considered as new expressions of classical structures. The principle of suboptimization (soft edges) is presented.

Intraocular lens design for treating high myopia based on individual eye model

NASA Astrophysics Data System (ADS)

Wang, Yang; Wang, Zhaoqi; Wang, Yan; Zuo, Tong

2007-02-01

In this research, we firstly design the phakic intraocular lens (PIOL) based on individual eye model with optical design software ZEMAX. The individual PIOL is designed to correct the defocus and astigmatism, and then we compare the PIOL power calculated from the individual eye model with that from the experiential formula. Close values of PIOL power are obtained between the individual eye model and the formula, but the suggested method has more accuracy with more functions. The impact of PIOL decentration on human eye is evaluated, including rotation decentration, flat axis decentration, steep axis decentration and axial movement of PIOL, which is impossible with traditional method. To control the PIOL decentration errors, we give the limit values of PIOL decentration for the specific eye in this study.

Threshold-Based Random Charging Scheme for Decentralized PEV Charging Operation in a Smart Grid.

PubMed

Kwon, Ojin; Kim, Pilkee; Yoon, Yong-Jin

2016-12-26

Smart grids have been introduced to replace conventional power distribution systems without real time monitoring for accommodating the future market penetration of plug-in electric vehicles (PEVs). When a large number of PEVs require simultaneous battery charging, charging coordination techniques have become one of the most critical factors to optimize the PEV charging performance and the conventional distribution system. In this case, considerable computational complexity of a central controller and exchange of real time information among PEVs may occur. To alleviate these problems, a novel threshold-based random charging (TBRC) operation for a decentralized charging system is proposed. Using PEV charging thresholds and random access rates, the PEVs themselves can participate in the charging requests. As PEVs with a high battery state do not transmit the charging requests to the central controller, the complexity of the central controller decreases due to the reduction of the charging requests. In addition, both the charging threshold and the random access rate are statistically calculated based on the average of supply power of the PEV charging system that do not require a real time update. By using the proposed TBRC with a tolerable PEV charging degradation, a 51% reduction of the PEV charging requests is achieved.

Threshold-Based Random Charging Scheme for Decentralized PEV Charging Operation in a Smart Grid

PubMed Central

Kwon, Ojin; Kim, Pilkee; Yoon, Yong-Jin

2016-01-01

Smart grids have been introduced to replace conventional power distribution systems without real time monitoring for accommodating the future market penetration of plug-in electric vehicles (PEVs). When a large number of PEVs require simultaneous battery charging, charging coordination techniques have become one of the most critical factors to optimize the PEV charging performance and the conventional distribution system. In this case, considerable computational complexity of a central controller and exchange of real time information among PEVs may occur. To alleviate these problems, a novel threshold-based random charging (TBRC) operation for a decentralized charging system is proposed. Using PEV charging thresholds and random access rates, the PEVs themselves can participate in the charging requests. As PEVs with a high battery state do not transmit the charging requests to the central controller, the complexity of the central controller decreases due to the reduction of the charging requests. In addition, both the charging threshold and the random access rate are statistically calculated based on the average of supply power of the PEV charging system that do not require a real time update. By using the proposed TBRC with a tolerable PEV charging degradation, a 51% reduction of the PEV charging requests is achieved. PMID:28035963

Decentralization, democratization, and health: the Philippine experiment.

PubMed

Langran, Irene V

2011-01-01

In 1991, the Philippines joined a growing list of countries that reformed health planning through decentralization. Reformers viewed decentralization as a tool that would solve multiple problems, leading to more meaningful democracy and more effective health planning. Today, nearly two decades after the passage of decentralization legislation, questions about the effectiveness of the reforms persist. Inadequate financing, inequity, and a lack of meaningful participation remain challenges, in many ways mirroring broader weaknesses of Philippine democracy. These concerns pose questions regarding the nature of contemporary decentralization, democratization, and health planning and whether these three strategies are indeed mutually enforcing.

“Tertius gaudens”: germplasm exchange networks and agroecological knowledge among home gardeners in the Iberian Peninsula

PubMed Central

2013-01-01

Background The idea that knowledge flows through social networks is implicit in research on traditional knowledge, but researchers have paid scant attention to the role of social networks in shaping its distribution. We bridge those two bodies of research and investigate a) the structure of network of exchange of plant propagation material (germplasm) and b) the relation between a person’s centrality in such network and his/her agroecological knowledge. Methods We study 10 networks of germplasm exchange (n = 363) in mountain regions of the Iberian Peninsula. Data were collected through participant observation, semi-structured interviews, and a survey. Results The networks display some structural characteristics (i.e., decentralization, presence of external actors) that could enhance the flow of knowledge and germplasm but also some characteristics that do not favor such flow (i.e., low density and fragmentation). We also find that a measure that captures the number of contacts of an individual in the germplasm exchange network is associated with the person’s agroecological knowledge. Conclusion Our findings highlight the importance of social relations in the construction of traditional knowledge. PMID:23883296

Feasibility of a clearing house for improved cooperation between telemedicine networks delivering humanitarian services: acceptability to network coordinators.

PubMed

Wootton, Richard; Bonnardot, Laurent; Geissbuhler, Antoine; Jethwani, Kamal; Kovarik, Carrie; McGoey, Suzanne; Person, Donald A; Vladzymyrskyy, Anton; Zolfo, Maria

2012-10-09

Telemedicine networks, which deliver humanitarian services, sometimes need to share expertise to find particular experts in other networks. It has been suggested that a mechanism for sharing expertise between networks (a 'clearing house') might be useful. To propose a mechanism for implementing the clearing house concept for sharing expertise, and to confirm its feasibility in terms of acceptability to the relevant networks. We conducted a needs analysis among eight telemedicine networks delivering humanitarian services. A small proportion of consultations (5-10%) suggested that networks may experience difficulties in finding the right specialists from within their own resources. With the assistance of key stakeholders, many of whom were network coordinators, various methods of implementing a clearing house were considered. One simple solution is to establish a central database holding information about consultants who have agreed to provide help to other networks; this database could be made available to network coordinators who need a specialist when none was available in their own network. The proposed solution was examined in a desktop simulation exercise, which confirmed its feasibility and probable value. This analysis informs full-scale implementation of a clearing house, and an associated examination of its costs and benefits.

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

NASA Astrophysics Data System (ADS)

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

2017-07-01

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

Energy Efficient Communication Using Relationships between Biological Signals for Ubiquitous Health Monitoring

NASA Astrophysics Data System (ADS)

Lee, Songjun; Na, Doosu; Koo, Bonmin

Wireless sensor networks with a star network topology are commonly applied for health monitoring systems. To determine the condition of a patient, sensor nodes are attached to the body to transmit the data to a coordinator. However, this process is inefficient because the coordinator is always communicating with each sensor node resulting in a data processing workload for the coordinator that becomes much greater than that of the sensor nodes. In this paper, a method is proposed to reduce the number of data transmissions from the sensor nodes to the coordinator by establishing a threshold for data from the biological signals to ensure that only relevant information is transmitted. This results in a dramatic reduction in power consumption throughout the entire network.

Multi-load Groups Coordinated Load Control Strategy Considering Power Network Constraints

NASA Astrophysics Data System (ADS)

Liu, Meng; Zhao, Binchao; Wang, Jun; Zhang, Guohui; Wang, Xin

2017-05-01

Loads with energy storage property can actively participate in power balance for power systems, this paper takes air conditioner as a controllable load example, proposing a multi-load groups coordinated load control strategy considering power network constraints. Firstly, two load control modes considering recovery of load diversity are designed, blocking power oscillation of aggregated air conditioners. As the same time, air conditioner temperature setpoint recovery control strategy is presented to avoid power recovery peak. Considering inherent characteristics of two load control modes, an coordinated load control mode is designed by combining the both. Basing on this, a multi-load groups coordinated load control strategy is proposed. During the implementing of load control, power network constraints should be satisfied. An indice which can reflect the security of power system operating is defined. By minimizing its value through optimization, the change of air conditioning loads’ aggregated power on each load bus can be calculated. Simulations are conducted on an air conditioners group and New England 10-generator 39-bus system, verifying the effectiveness of the proposed multi-load groups coordinated load control strategy considering power network constraints.

Operator Objective Function Guidance for a Real-Time Unmanned Vehicle Scheduling Algorithm

DTIC Science & Technology

2012-12-01

Consensus - Based Decentralized Auctions for Robust Task Allocation ,” IEEE Transactions on Robotics and Automation, Vol. 25, No. 4, No. 4, 2009, pp. 912...planning for the fleet. The decentralized task planner used in OPS-USERS is the consensus - based bundle algorithm (CBBA), a decentralized , polynomial...and surveillance (OPS-USERS), which leverages decentralized algorithms for vehicle routing and task allocation . This

Assessing the challenges of multi-scope clinical research sites: an example from NIH HIV/AIDS clinical trials networks.

PubMed

Rosas, Scott R; Cope, Marie T; Villa, Christie; Motevalli, Mahnaz; Utech, Jill; Schouten, Jeffrey T

2014-04-01

Large-scale, multi-network clinical trials are seen as a means for efficient and effective utilization of resources with greater responsiveness to new discoveries. Formal structures instituted within the National Institutes of Health (NIH) HIV/AIDS Clinical Trials facilitate collaboration and coordination across networks and emphasize an integrated approach to HIV/AIDS vaccine, prevention and therapeutics clinical trials. This study examines the joint usage of clinical research sites as means of gaining efficiency, extending capacity, and adding scientific value to the networks. A semi-structured questionnaire covering eight clinical management domains was administered to 74 (62% of sites) clinical site coordinators at single- and multi-network sites to identify challenges and efficiencies related to clinical trials management activities and coordination with multi-network units. Overall, respondents at multi-network sites did not report more challenges than single-network sites, but did report unique challenges to overcome including in the areas of study prioritization, community engagement, staff education and training, and policies and procedures. The majority of multi-network sites reported that such affiliations do allow for the consolidation and cost-sharing of research functions. Suggestions for increasing the efficiency or performance of multi-network sites included streamlining standards and requirements, consolidating protocol activation methods, using a single cross-network coordinating centre, and creating common budget and payment mechanisms. The results of this assessment provide important information to consider in the design and management of multi-network configurations for the NIH HIV/AIDS Clinical Trials Networks, as well as others contemplating and promoting the concept of multi-network settings. © 2013 John Wiley & Sons Ltd.

Governing decentralization in health care under tough budget constraint: what can we learn from the Italian experience?

PubMed

Tediosi, Fabrizio; Gabriele, Stefania; Longo, Francesco

2009-05-01

In many European countries, since the World War II, there has been a trend towards decentralization of health policy to lower levels of governments, while more recently there have been re-centralization processes. Whether re-centralization will be the new paradigm of European health policy or not is difficult to say. In the Italian National Health Service (SSN) decentralization raised two related questions that might be interesting for the international debate on decentralization in health care: (a) what sort of regulatory framework and institutional balances are required to govern decentralization in health care in a heterogeneous country under tough budget constraints? (b) how can it be ensured that the most advanced parts of the country remain committed to solidarity, supporting the weakest ones? To address these questions this article describes the recent trends in SSN funding and expenditure, it reviews the strategy adopted by the Italian government for governing the decentralization process and discusses the findings to draw policy conclusions. The main lessons emerging from this experience are that: (1) when the differences in administrative and policy skills, in socio-economic standards and social capital are wide, decentralization may lead to undesirable divergent evolution paths; (2) even in decentralized systems, the role of the Central government can be very important to contain health expenditure; (3) a strong governance of the Central government may help and not hinder the enforcement of decentralization; and (4) supporting the weakest Regions and maintaining inter-regional solidarity is hard but possible. In Italy, despite an increasing role of the Central government in steering the SSN, the pattern of regional decentralization of health sector decision making does not seem at risk. Nevertheless, the Italian case confirms the complexity of decentralization and re-centralization processes that sometimes can be paradoxically reinforcing each other.

Health sector decentralization and local decision-making: Decision space, institutional capacities and accountability in Pakistan.

PubMed

Bossert, Thomas John; Mitchell, Andrew David

2011-01-01

Health sector decentralization has been widely adopted to improve delivery of health services. While many argue that institutional capacities and mechanisms of accountability required to transform decentralized decision-making into improvements in local health systems are lacking, few empirical studies exist which measure or relate together these concepts. Based on research instruments administered to a sample of 91 health sector decision-makers in 17 districts of Pakistan, this study analyzes relationships between three dimensions of decentralization: decentralized authority (referred to as "decision space"), institutional capacities, and accountability to local officials. Composite quantitative indicators of these three dimensions were constructed within four broad health functions (strategic and operational planning, budgeting, human resources management, and service organization/delivery) and on an overall/cross-function basis. Three main findings emerged. First, district-level respondents report varying degrees of each dimension despite being under a single decentralization regime and facing similar rules across provinces. Second, within dimensions of decentralization-particularly decision space and capacities-synergies exist between levels reported by respondents in one function and those reported in other functions (statistically significant coefficients of correlation ranging from ρ=0.22 to ρ=0.43). Third, synergies exist across dimensions of decentralization, particularly in terms of an overall indicator of institutional capacities (significantly correlated with both overall decision space (ρ=0.39) and accountability (ρ=0.23)). This study demonstrates that decentralization is a varied experience-with some district-level officials making greater use of decision space than others and that those who do so also tend to have more capacity to make decisions and are held more accountable to elected local officials for such choices. These findings suggest that Pakistan's decentralization policy should focus on synergies among dimensions of decentralization to encouraging more use of de jure decision space, work toward more uniform institutional capacity, and encourage greater accountability to local elected officials. Copyright © 2010 Elsevier Ltd. All rights reserved.

Analysing collaboration among HIV agencies through combining network theory and relational coordination.

PubMed

Khosla, Nidhi; Marsteller, Jill Ann; Hsu, Yea Jen; Elliott, David L

2016-02-01

Agencies with different foci (e.g. nutrition, social, medical, housing) serve people living with HIV (PLHIV). Serving needs of PLHIV comprehensively requires a high degree of coordination among agencies which often benefits from more frequent communication. We combined Social Network theory and Relational Coordination theory to study coordination among HIV agencies in Baltimore. Social Network theory implies that actors (e.g., HIV agencies) establish linkages amongst themselves in order to access resources (e.g., information). Relational Coordination theory suggests that high quality coordination among agencies or teams relies on the seven dimensions of frequency, timeliness and accuracy of communication, problem-solving communication, knowledge of agencies' work, mutual respect and shared goals. We collected data on frequency of contact from 57 agencies using a roster method. Response options were ordinal ranging from 'not at all' to 'daily'. We analyzed data using social network measures. Next, we selected agencies with which at least one-third of the sample reported monthly or more frequent interaction. This yielded 11 agencies whom we surveyed on seven relational coordination dimensions with questions scored on a Likert scale of 1-5. Network density, defined as the proportion of existing connections to all possible connections, was 20% when considering monthly or higher interaction. Relational coordination scores from individual agencies to others ranged between 1.17 and 5.00 (maximum possible score 5). The average scores for different dimensions across all agencies ranged between 3.30 and 4.00. Shared goals (4.00) and mutual respect (3.91) scores were highest, while scores such as knowledge of each other's work and problem-solving communication were relatively lower. Combining theoretically driven analyses in this manner offers an innovative way to provide a comprehensive picture of inter-agency coordination and the quality of exchange that underlies collaborative ties. These methods together can identify areas that could be targeted to promote closer ties. Copyright © 2015 Elsevier Ltd. All rights reserved.

Highways and Urban Decentralization

DOT National Transportation Integrated Search

1998-01-01

This report documents a retrospective study of the relationship between highways and urban decentralization. We see decentralization as caused largely by the increased consumption of land by residents and businesses which occurs mainly because of hig...

Learning in networks: individual teacher learning versus organizational learning in a regional health-promoting schools network.

PubMed

Flaschberger, Edith; Gugglberger, Lisa; Dietscher, Christina

2013-12-01

To change a school into a health-promoting organization, organizational learning is required. The evaluation of an Austrian regional health-promoting schools network provides qualitative data on the views of the different stakeholders on learning in this network (steering group, network coordinator and representatives of the network schools; n = 26). Through thematic analysis and deep-structure analyses, the following three forms of learning in the network were identified: (A) individual learning through input offered by the network coordination, (B) individual learning between the network schools, i.e. through exchange between the representatives of different schools and (C) learning within the participating schools, i.e. organizational learning. Learning between (B) or within the participating schools (C) seems to be rare in the network; concepts of individual teacher learning are prevalent. Difficulties detected relating to the transfer of information from the network to the member schools included barriers to organizational learning such as the lack of collaboration, coordination and communication in the network schools, which might be effects of the school system in which the observed network is located. To ensure connectivity of the information offered by the network, more emphasis should be put on linking health promotion to school development and the core processes of schools.

Modeling and Simulation Network Data Standards

DTIC Science & Technology

2011-09-30

COMBATXXI Movement Logger Data Output Dictionary. Field # Geocentric Coordinates (GCC) Heading Geodetic Coordinates (GDC) Heading Universal...B-8 Field # Geocentric Coordinates (GCC) Heading Geodetic Coordinates (GDC) Heading Universal Transverse Mercator (UTM) Heading...FKSM Fort Knox Supplemental Material FM field manual GCC geocentric coordinates GDC geodetic coordinates GIG global information grid

Agent-based real-time signal coordination in congested networks.

DOT National Transportation Integrated Search

2014-01-01

This study is the continuation of a previous NEXTRANS study on agent-based reinforcement : learning methods for signal coordination in congested networks. In the previous study, the : formulation of a real-time agent-based traffic signal control in o...

Peeling the Onion: Why Centralized Control / Decentralized Execution Works

DTIC Science & Technology

2014-04-01

March–April 2014 Air & Space Power Journal | 24 Feature Peeling the Onion Why Centralized Control / Decentralized Execution Works Lt Col Alan Docauer...DATES COVERED 00-00-2014 to 00-00-2014 4. TITLE AND SUBTITLE Peeling the Onion : Why Centralized Control / Decentralized Execution Works 5a...Air & Space Power Journal | 25 Docauer Peeling the Onion Feature What Is Centralized Control / Decentralized Execution? Emerging in the aftermath of

A novel method for 3D measurement of RFID multi-tag network based on matching vision and wavelet

NASA Astrophysics Data System (ADS)

Zhuang, Xiao; Yu, Xiaolei; Zhao, Zhimin; Wang, Donghua; Zhang, Wenjie; Liu, Zhenlu; Lu, Dongsheng; Dong, Dingbang

2018-07-01

In the field of radio frequency identification (RFID), the three-dimensional (3D) distribution of RFID multi-tag networks has a significant impact on their reading performance. At the same time, in order to realize the anti-collision of RFID multi-tag networks in practical engineering applications, the 3D distribution of RFID multi-tag networks must be measured. In this paper, a novel method for the 3D measurement of RFID multi-tag networks is proposed. A dual-CCD system (vertical and horizontal cameras) is used to obtain images of RFID multi-tag networks from different angles. Then, the wavelet threshold denoising method is used to remove noise in the obtained images. The template matching method is used to determine the two-dimensional coordinates and vertical coordinate of each tag. The 3D coordinates of each tag are obtained subsequently. Finally, a model of the nonlinear relation between the 3D coordinate distribution of the RFID multi-tag network and the corresponding reading distance is established using the wavelet neural network. The experiment results show that the average prediction relative error is 0.71% and the time cost is 2.17 s. The values of the average prediction relative error and time cost are smaller than those of the particle swarm optimization neural network and genetic algorithm–back propagation neural network. The time cost of the wavelet neural network is about 1% of that of the other two methods. The method proposed in this paper has a smaller relative error. The proposed method can improve the real-time performance of RFID multi-tag networks and the overall dynamic performance of multi-tag networks.

Algorithms for Lightweight Key Exchange †

PubMed Central

Santonja, Juan; Zamora, Antonio

2017-01-01

Public-key cryptography is too slow for general purpose encryption, with most applications limiting its use as much as possible. Some secure protocols, especially those that enable forward secrecy, make a much heavier use of public-key cryptography, increasing the demand for lightweight cryptosystems that can be implemented in low powered or mobile devices. This performance requirements are even more significant in critical infrastructure and emergency scenarios where peer-to-peer networks are deployed for increased availability and resiliency. We benchmark several public-key key-exchange algorithms, determining those that are better for the requirements of critical infrastructure and emergency applications and propose a security framework based on these algorithms and study its application to decentralized node or sensor networks. PMID:28654006

Use of DHCP to provide essential information for care and management of HIV patients.

PubMed

Pfeil, C N; Ivey, J L; Hoffman, J D; Kuhn, I M

1991-01-01

The Department of Veterans' Affairs (VA) has reported over 10,000 Acquired Immune Deficiency Syndrome (AIDS) cases since the beginning of the epidemic. These cases were distributed throughout 152 of the VA's network of 172 medical centers and outpatient clinics. This network of health care facilities presents a unique opportunity to provide computer based information systems for clinical care and resource monitoring for these patients. The VA further facilitates such a venture through its commitment to the Decentralized Hospital Computer Program (DHCP). This paper describes a new application within DHCP known as the VA's HIV Registry. This project addresses the need to support clinical information as well as the added need to manage the resources necessary to care for HIV patients.

Design of a patient-centered, multi-institutional healthcare information network using peer-to-peer communication in a highly distributed architecture.

PubMed

Geissbuhler, Antoine; Spahni, Stéphane; Assimacopoulos, André; Raetzo, Marc-André; Gobet, Gérard

2004-01-01

to design a community healthcare information network for all 450,000 citizen in the State of Geneva, Switzerland, connecting public and private healthcare professionals. Requirements include the decentralized storage of information at the source of its production, the creation of a virtual patient record at the time of the consultation, the control by the patient of the access rights to the information, and the interoperability with other similar networks at the national and european level. a participative approach and real-world pilot projects are used to design, test and validate key components of the network, including its technical architecture and the strategy for the management of access rights by the patients. a distributed architecture using peer-to-peer communication of information mediators can implement the various requirements while limiting to an absolute minimum the amount of centralized information. Access control can be managed by the patient with the help of a medical information mediator, the physician of trust.

Promoting evaluation capacity building in a complex adaptive system.

PubMed

Lawrenz, Frances; Kollmann, Elizabeth Kunz; King, Jean A; Bequette, Marjorie; Pattison, Scott; Nelson, Amy Grack; Cohn, Sarah; Cardiel, Christopher L B; Iacovelli, Stephanie; Eliou, Gayra Ostgaard; Goss, Juli; Causey, Lauren; Sinkey, Anne; Beyer, Marta; Francisco, Melanie

2018-04-10

This study provides results from an NSF funded, four year, case study about evaluation capacity building in a complex adaptive system, the Nanoscale Informal Science Education Network (NISE Net). The results of the Complex Adaptive Systems as a Model for Network Evaluations (CASNET) project indicate that complex adaptive system concepts help to explain evaluation capacity building in a network. The NISE Network was found to be a complex learning system that was supportive of evaluation capacity building through feedback loops that provided for information sharing and interaction. Participants in the system had different levels of and sources of evaluation knowledge. To be successful at building capacity, the system needed to have a balance between both centralized and decentralized control, coherence, redundancy, and diversity. Embeddedness of individuals within the system also provided support and moved the capacity of the system forward. Finally, success depended on attention being paid to the control of resources. Implications of these findings are discussed. Copyright © 2018 Elsevier Ltd. All rights reserved.

Ubiquitous healthcare computing with SEnsor Grid Enhancement with Data Management System (SEGEDMA).

PubMed

Preve, Nikolaos

2011-12-01

Wireless Sensor Network (WSN) can be deployed to monitor the health of patients suffering from critical diseases. Also a wireless network consisting of biomedical sensors can be implanted into the patient's body and can monitor the patients' conditions. These sensor devices, apart from having an enormous capability of collecting data from their physical surroundings, are also resource constraint in nature with a limited processing and communication ability. Therefore we have to integrate them with the Grid technology in order to process and store the collected data by the sensor nodes. In this paper, we proposed the SEnsor Grid Enhancement Data Management system, called SEGEDMA ensuring the integration of different network technologies and the continuous data access to system users. The main contribution of this work is to achieve the interoperability of both technologies through a novel network architecture ensuring also the interoperability of Open Geospatial Consortium (OGC) and HL7 standards. According to the results, SEGEDMA can be applied successfully in a decentralized healthcare environment.

Perturbed cooperative-state feedback strategy for model predictive networked control of interconnected systems.

PubMed

Tran, Tri; Ha, Q P

2018-01-01

A perturbed cooperative-state feedback (PSF) strategy is presented for the control of interconnected systems in this paper. The subsystems of an interconnected system can exchange data via the communication network that has multiple connection topologies. The PSF strategy can resolve both issues, the sensor data losses and the communication network breaks, thanks to the two components of the control including a cooperative-state feedback and a perturbation variable, e.g., u i =K ij x j +w i . The PSF is implemented in a decentralized model predictive control scheme with a stability constraint and a non-monotonic storage function (ΔV(x(k))≥0), derived from the dissipative systems theory. Numerical simulation for the automatic generation control problem in power systems is studied to illustrate the effectiveness of the presented PSF strategy. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

A networked voting rule for democratic representation

NASA Astrophysics Data System (ADS)

Hernández, Alexis R.; Gracia-Lázaro, Carlos; Brigatti, Edgardo; Moreno, Yamir

2018-03-01

We introduce a general framework for exploring the problem of selecting a committee of representatives with the aim of studying a networked voting rule based on a decentralized large-scale platform, which can assure a strong accountability of the elected. The results of our simulations suggest that this algorithm-based approach is able to obtain a high representativeness for relatively small committees, performing even better than a classical voting rule based on a closed list of candidates. We show that a general relation between committee size and representatives exists in the form of an inverse square root law and that the normalized committee size approximately scales with the inverse of the community size, allowing the scalability to very large populations. These findings are not strongly influenced by the different networks used to describe the individuals' interactions, except for the presence of few individuals with very high connectivity which can have a marginal negative effect in the committee selection process.

Different approaches for centralized and decentralized water system management in multiple decision makers' problems

NASA Astrophysics Data System (ADS)

Anghileri, D.; Giuliani, M.; Castelletti, A.

2012-04-01

There is a general agreement that one of the most challenging issues related to water system management is the presence of many and often conflicting interests as well as the presence of several and independent decision makers. The traditional approach to multi-objective water systems management is a centralized management, in which an ideal central regulator coordinates the operation of the whole system, exploiting all the available information and balancing all the operating objectives. Although this approach allows to obtain Pareto-optimal solutions representing the maximum achievable benefit, it is based on assumptions which strongly limits its application in real world contexts: 1) top-down management, 2) existence of a central regulation institution, 3) complete information exchange within the system, 4) perfect economic efficiency. A bottom-up decentralized approach seems therefore to be more suitable for real case applications since different reservoir operators may maintain their independence. In this work we tested the consequences of a change in the water management approach moving from a centralized toward a decentralized one. In particular we compared three different cases: the centralized management approach, the independent management approach where each reservoir operator takes the daily release decision maximizing (or minimizing) his operating objective independently from each other, and an intermediate approach, leading to the Nash equilibrium of the associated game, where different reservoir operators try to model the behaviours of the other operators. The three approaches are demonstrated using a test case-study composed of two reservoirs regulated for the minimization of flooding in different locations. The operating policies are computed by solving one single multi-objective optimal control problem, in the centralized management approach; multiple single-objective optimization problems, i.e. one for each operator, in the independent case; using techniques related to game theory for the description of the interaction between the two operators, in the last approach. Computational results shows that the Pareto-optimal control policies obtained in the centralized approach dominate the control policies of both the two cases of decentralized management and that the so called price of anarchy increases moving toward the independent management approach. However, the Nash equilibrium solution seems to be the most promising alternative because it represents a good compromise in maximizing management efficiency without limiting the behaviours of the reservoir operators.

A distributed incentive compatible pricing mechanism for P2P networks

NASA Astrophysics Data System (ADS)

Zhang, Jie; Zhao, Zheng; Xiong, Xiao; Shi, Qingwei

2007-09-01

Peer-to-Peer (P2P) systems are currently receiving considerable interest. However, as experience with P2P networks shows, the selfish behaviors of peers may lead to serious problems of P2P network, such as free-riding and white-washing. In order to solve these problems, there are increasing considerations on reputation system design in the study of P2P networks. Most of the existing works is concerning probabilistic estimation or social networks to evaluate the trustworthiness for a peer to others. However, these models can not be efficient all the time. In this paper, our aim is to provide a general mechanism that can maximize P2P networks social welfare in a way of Vickrey-Clarke-Groves family, while assuming every peer in P2P networks is rational and selfish, which means they only concern about their own outcome. This mechanism has some desirable properties using an O(n) algorithm: (1) incentive compatibility, every peer truly report its connection type; (2) individually rationality; and (3) fully decentralized, we design a multiple-principal multiple-agent model, concerning about the service provider and service requester individually.

A junction-tree based learning algorithm to optimize network wide traffic control: A coordinated multi-agent framework

DOE PAGES

Zhu, Feng; Aziz, H. M. Abdul; Qian, Xinwu; ...

2015-01-31

Our study develops a novel reinforcement learning algorithm for the challenging coordinated signal control problem. Traffic signals are modeled as intelligent agents interacting with the stochastic traffic environment. The model is built on the framework of coordinated reinforcement learning. The Junction Tree Algorithm (JTA) based reinforcement learning is proposed to obtain an exact inference of the best joint actions for all the coordinated intersections. Moreover, the algorithm is implemented and tested with a network containing 18 signalized intersections in VISSIM. Finally, our results show that the JTA based algorithm outperforms independent learning (Q-learning), real-time adaptive learning, and fixed timing plansmore » in terms of average delay, number of stops, and vehicular emissions at the network level.« less

Dynamic Centralized and Decentralized Control Systems

DOT National Transportation Integrated Search

1977-09-01

This report develops a systematic method for designing suboptimal decentralized control systems. The method is then applied to the design of a decentralized controller for a freeway-corridor system. A freeway corridor is considered to be a system of ...

[Analysis of the healthcare service decentralization process in Côte d'Ivoire].

PubMed

Soura, B D; Coulibaly, S S

2014-01-01

The decentralization of healthcare services is becoming increasingly important in strategies of public sector management. This concept is analyzed from various points of view, including legal, economic, political, and sociological. Several typologies have been proposed in the literature to analyze this decentralization process, which can take different forms ranging from simple deconcentration to more elaborate devolution. In some instances, decentralization can be analyzed by the degree of autonomy given to local authorities. This article applies these typologies to analyze the healthcare system decentralization process in Cote d'Ivoire. Special attention is paid to the new forms of community healthcare organizations. These decentralized structures enjoy a kind of autonomy, with characteristics closer to those of devolution. The model might serve as an example for population involvement in defining and managing healthcare problems in Cote d'Ivoire. We end with proposals for the improvement of the process.

A comparison of decentralized, distributed, and centralized vibro-acoustic control.

PubMed

Frampton, Kenneth D; Baumann, Oliver N; Gardonio, Paolo

2010-11-01

Direct velocity feedback control of structures is well known to increase structural damping and thus reduce vibration. In multi-channel systems the way in which the velocity signals are used to inform the actuators ranges from decentralized control, through distributed or clustered control to fully centralized control. The objective of distributed controllers is to exploit the anticipated performance advantage of the centralized control while maintaining the scalability, ease of implementation, and robustness of decentralized control. However, and in seeming contradiction, some investigations have concluded that decentralized control performs as well as distributed and centralized control, while other results have indicated that distributed control has significant performance advantages over decentralized control. The purpose of this work is to explain this seeming contradiction in results, to explore the effectiveness of decentralized, distributed, and centralized vibro-acoustic control, and to expand the concept of distributed control to include the distribution of the optimization process and the cost function employed.

[Report of the third meeting of the coordinators of the regional MRP networks in Germany on 15 and 16 December 2011 at the Robert Koch Institute].

PubMed

Mielke, M

2012-11-01

Since 2004 the Robert Koch-Institute has supported the formation of regional networks for prevention of the spread of methicillin-resistant Staphylococcus aureus and multiresistant pathogens (MRSA/MRP, EpiBull 5/2005)). The third meeting of the coordinators of the regional MRP networks in Germany took place on 15 and 16 December 2011. A total of 60 representatives of the Public Health Services from 12 states participated. It must be emphasized that in the meantime many successfully established networks are active and not all coordinators of existing networks could participate merely due to the organizational format. Interested parties can obtain a good overview via a link to the corresponding internet homepage of each state under http://www.rki.de → Infektionsschutz → Krankenhaushygiene → Regionale Netzwerke. In summary it was clear that the number and the activity of regional MRP networks in Germany have further increased. The networks can synergistically benefit from important experiences through the different individual focal points of each network and a corresponding exchange of ideas.

Facile solid-state synthesis of Ni@C nanosheet-assembled hierarchical network for high-performance lithium storage

NASA Astrophysics Data System (ADS)

Gu, Jinghe; Li, Qiyun; Zeng, Pan; Meng, Yulin; Zhang, Xiukui; Wu, Ping; Zhou, Yiming

2017-08-01

Micro/nano-architectured transition-metal@C hybrids possess unique structural and compositional features toward lithium storage, and are thus expected to manifest ideal anodic performances in advanced lithium-ion batteries (LIBs). Herein, we propose a facile and scalable solid-state coordination and subsequent pyrolysis route for the formation of a novel type of micro/nano-architectured transition-metal@C hybrid (i.e., Ni@C nanosheet-assembled hierarchical network, Ni@C network). Moreover, this coordination-pyrolysis route has also been applied for the construction of bare carbon network using zinc salts instead of nickel salts as precursors. When applied as potential anodic materials in LIBs, the Ni@C network exhibits Ni-content-dependent electrochemical performances, and the partially-etched Ni@C network manifests markedly enhanced Li-storage performances in terms of specific capacities, cycle life, and rate capability than the pristine Ni@C network and carbon network. The proposed solid-state coordination and pyrolysis strategy would open up new opportunities for constructing micro/nano-architectured transition-metal@C hybrids as advanced anode materials for LIBs.

Applications of laser ranging and VLBI observations for selenodetic control

NASA Technical Reports Server (NTRS)

Fajemirokun, F. A.

1971-01-01

The observation equations necessary to utilize lunar laser ranging and very long baseline interferometry measurements were developed for the establishment of a primary control network on the moon. The network consists of coordinates of moon points in the selenodetic Cartesian coordinate system, which is fixed to the lunar body, oriented along the three principal axes of inertia of the moon, and centered at the lunar center of mass. The observation equations derived are based on a general model in which the unknown parameters included: the selenodetic Cartesian coordinates, the geocentric coordinates of earth stations, parameters of the orientation of the selenodetic coordinate system with respect to a fixed celestial system, the parameters of the orientation of the average terrestrial coordinate system with respect to a fixed celestial coordinate system, and the geocentric coordinates of the center of mass of the moon, given by a lunar ephemeris.

[Barriers and facilitators to health care coordination in two integrated health care organizations in Catalonia (Spain)].

PubMed

Vargas Lorenzo, Ingrid; Vázquez Navarrete, M Luisa

2007-01-01

To analyze 2 integrated delivery systems (IDS) in Catalonia and identify areas for future development to improve their effectiveness. An exploratory, descriptive, qualitative study was carried out based on case studies by means of document analysis and semi-structured individual interviews. A criterion sample of cases and, for each case, of documents and informants was selected. Study cases consisted of the Consorci Sanitari del Maresme (CSdM) and the Consorci Sanitari de Terrassa/Fundació Hospital Sant Llàtzer (FHSLL). A total of 127 documents were analyzed and 29 informants were interviewed: IDS managers (n = 10), technical staff (n = 5), operational unit managers (n = 5) and health professionals (n = 9). Content analysis was conducted, with mixed generation of categories and segmentation by cases and subjects. CSdM and CSdT/FHSLL are health care organizations with backward vertical integration, total services production, and real (CSdM) and virtual (CSdT/FHSLL) ownership. Funds are allocated by care level. The governing body is centralized in CSdM and decentralized in CSdT/FHSLL. In both organizations, the global objectives are oriented toward improving coordination and efficiency but are not in line with those of the operational units. Both organizations present a functional structure with integration of support functions and utilize mechanisms for collaboration between care levels based on work processes standardization. Both IDS present facilitators and barriers to health care coordination. To improve coordination, changes in external elements (payment mechanism) and in internal elements (governing body role, organizational structure and coordination mechanisms) are required.

[Use of social and health primary care services for older people with complex needs: Comparison of three types of gerontological coordination].

PubMed

de Stampa, M; Bagaragaza, E; Herr, M; Aegerter, P; Vedel, I; Bergman, H; Ankri, J

2014-10-01

Older people with complex needs live mainly at home. Several types of gerontological coordinations have been established on the French territory to meet their needs and to implement social and primary health care services. But we do not have any information on the use of these services at home as a function of the coordination method used. We compared the use of home care services for older people with complex needs in three types of coordination with 12 months' follow-up. The three coordinations regrouped a gerontological network with case management (n=105 persons), a nursing home service (SSIAD) with a nurse coordination (n=206 persons) and an informal coordination with a non-professional caregiver (n=117 persons). At t0, the older people addressed to the gerontological network had less access to the services offered at home; those followed by the SSIAD had the highest number of services and of weekly interventions. Hours of weekly services were two-fold higher in those with the informal coordination. At t12, there was an improvement in access to services for the network group with case management and an overall increase in the use of professional services at home with no significant difference between the three groups. The use of social and primary health care services showed differences between the three gerontological coordinations. The one-year evolution in the use of home services was comparable between the groups without an explosion in the number of services in the network group with case management. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

Many-to-Many Multicast Routing Schemes under a Fixed Topology

PubMed Central

Ding, Wei; Wang, Hongfa; Wei, Xuerui

2013-01-01

Many-to-many multicast routing can be extensively applied in computer or communication networks supporting various continuous multimedia applications. The paper focuses on the case where all users share a common communication channel while each user is both a sender and a receiver of messages in multicasting as well as an end user. In this case, the multicast tree appears as a terminal Steiner tree (TeST). The problem of finding a TeST with a quality-of-service (QoS) optimization is frequently NP-hard. However, we discover that it is a good idea to find a many-to-many multicast tree with QoS optimization under a fixed topology. In this paper, we are concerned with three kinds of QoS optimization objectives of multicast tree, that is, the minimum cost, minimum diameter, and maximum reliability. All of three optimization problems are distributed into two types, the centralized and decentralized version. This paper uses the dynamic programming method to devise an exact algorithm, respectively, for the centralized and decentralized versions of each optimization problem. PMID:23589706

Community pharmacist participation in a practice-based research network: a report from the Medication Safety Research Network of Indiana (Rx-SafeNet).

PubMed

Patel, Puja; Hemmeger, Heather; Kozak, Mary Ann; Gernant, Stephanie A; Snyder, Margie E

2015-01-01

To describe the experiences and opinions of pharmacists serving as site coordinators for the Medication Safety Research Network of Indiana (Rx-SafeNet). Retail chain, independent, and hospital/health system outpatient community pharmacies throughout Indiana, with a total of 127 pharmacy members represented by 26 site coordinators. Rx-SafeNet, a statewide practice-based research network (PBRN) formed in 2010 and administered by the Purdue University College of Pharmacy. Barriers and facilitators to participation in available research studies, confidence participating in research, and satisfaction with overall network communication. 22 of 26 site coordinators participated, resulting in an 85% response rate. Most (72.2%) of the respondents had received a doctor of pharmacy degree, and 13.6% had postgraduate year (PGY)1 residency training. The highest reported benefits of PBRN membership were an enhanced relationship with the Purdue University College of Pharmacy (81% agreed or strongly agreed) and enhanced professional development (80% agreed or strongly agreed). Time constraints were identified as the greatest potential barrier to network participation, reported by 62% of respondents. In addition, the majority (59%) of survey respondents identified no prior research experience. Last, respondents' confidence in performing research appeared to increase substantially after becoming network members, with 43% reporting a lack of confidence in engaging in research before joining the network compared with 90% reporting confidence after joining the network. In general, Rx-SafeNet site coordinators appeared to experience increased confidence in research engagement after joining the network. While respondents identified a number of benefits associated with network participation, concerns about potential time constraints remained a key barrier to participation. These findings will assist network leadership in identifying opportunities to positively increase member participation in the future.

Doctors' opinion on the contribution of coordination mechanisms to improving clinical coordination between primary and outpatient secondary care in the Catalan national health system.

PubMed

Aller, Marta-Beatriz; Vargas, Ingrid; Coderch, Jordi; Vázquez, Maria-Luisa

2017-12-22

Clinical coordination is considered a health policy priority as its absence can lead to poor quality of care and inefficiency. A key challenge is to identify which strategies should be implemented to improve coordination. The aim is to analyse doctors' opinions on the contribution of mechanisms to improving clinical coordination between primary and outpatient secondary care and the factors influencing their use. A qualitative descriptive study in three healthcare networks of the Catalan national health system. A two-stage theoretical sample was designed: in the first stage, networks with different management models were selected; in the second, primary care (n = 26) and secondary care (n = 24) doctors. Data were collected using semi-structured interviews. Final sample size was reached by saturation. A thematic content analysis was conducted, segmented by network and care level. With few differences across networks, doctors identified similar mechanisms contributing to clinical coordination: 1) shared EMR facilitating clinical information transfer and uptake; 2) mechanisms enabling problem-solving communication and agreement on clinical approaches, which varied across networks (joint clinical case conferences, which also promote mutual knowledge and training of primary care doctors; virtual consultations through EMR and email); and 3) referral protocols and use of the telephone facilitating access to secondary care after referrals. Doctors identified organizational (insufficient time, incompatible timetables, design of mechanisms) and professional factors (knowing each other, attitude towards collaboration, concerns over misdiagnosis) that influence the use of mechanisms. Mechanisms that most contribute to clinical coordination are feedback mechanisms, that is those based on mutual adjustment, that allow doctors to exchange information and communicate. Their use might be enhanced by focusing on adequate working conditions, mechanism design and creating conditions that promote mutual knowledge and positive attitudes towards collaboration.

The Effect of Fiscal Decentralization on Under-five Mortality in Iran: A Panel Data Analysis.

PubMed

Samadi, Ali Hussein; Keshtkaran, Ali; Kavosi, Zahra; Vahedi, Sajad

2013-11-01

Fiscal Decentralization (FD) in many cases is encouraged as a strong means of improving the efficiency and equity in the provision of public goods, such as healthcare services. This issue has urged the researchers to experimentally examine the relationship between fiscal decentralization indicators and health outcomes. In this study we examine the effect of Fiscal Decentralization in Medical Universities (FDMU) and Fiscal Decentralization in Provincial Revenues (FDPR) on Under-Five Mortality Rate (U5M) in provinces of Iran over the period between 2007 and 2010. We employed panel data methods in this article. The results of the Pesaran CD test demonstrated that most of the variables used in the analysis were cross-sectionally dependent. The Hausman test results suggested that fixed-effects were more appropriate to estimate our model. We estimated the fixed-effect model by using Driscoll-Kraay standard errors as a remedy for cross-sectional dependency. According to the findings of this research, fiscal decentralization in the health sector had a negative impact on U5M. On the other hand, fiscal decentralization in provincial revenues had a positive impact on U5M. In addition, U5M had a negative association with the density of physicians, hospital beds, and provincial GDP per capita, but a positive relationship with Gini coefficient and unemployment. The findings of our study indicated that fiscal decentralization should be emphasized in the health sector. The results suggest the need for caution in the implementation of fiscal decentralization in provincial revenues.

IGS Network Coordinator Report - 2002

NASA Technical Reports Server (NTRS)

Moore, Angelyn

2004-01-01

The IGS network is a set of permanent, continuously-operating, dual-frequency GPS stations operated by over 100 worldwide agencies. The dataset is pooled at IGS Data Centers for routine use by IGS Analysis Centers in creating precise IGS products, as well as free access by other analysts around the world. The IGS Central Bureau hosts the IGS Network Coordinator, who assures adherence to standards and provides information regarding the IGS network via the Central Bureau Information System website at http://igscb.jpl.nasa.gov.

Disturbance decoupling, decentralized control and the Riccati equation

NASA Technical Reports Server (NTRS)

Garzia, M. R.; Loparo, K. A.; Martin, C. F.

1981-01-01

The disturbance decoupling and optimal decentralized control problems are looked at using identical mathematical techniques. A statement of the problems and the development of their solution approach is presented. Preliminary results are given for the optimal decentralized control problem.

Analyzing Human Communication Networks in Organizations: Applications to Management Problems.

ERIC Educational Resources Information Center

Farace, Richard V.; Danowski, James A.

Investigating the networks of communication in organizations leads to an understanding of efficient and inefficient information dissemination as practiced in large systems. Most important in organizational communication is the role of the "liaison person"--the coordinator of intercommunication. When functioning efficiently, coordinators maintain…

Differentially Private Distributed Sensing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fink, Glenn A.

The growth of the Internet of Things (IoT) creates the possibility of decentralized systems of sensing and actuation, potentially on a global scale. IoT devices connected to cloud networks can offer Sensing and Actuation as a Service (SAaaS) enabling networks of sensors to grow to a global scale. But extremely large sensor networks can violate privacy, especially in the case where IoT devices are mobile and connected directly to the behaviors of people. The thesis of this paper is that by adapting differential privacy (adding statistically appropriate noise to query results) to groups of geographically distributed sensors privacy could bemore » maintained without ever sending all values up to a central curator and without compromising the overall accuracy of the data collected. This paper outlines such a scheme and performs an analysis of differential privacy techniques adapted to edge computing in a simulated sensor network where ground truth is known. The positive and negative outcomes of employing differential privacy in distributed networks of devices are discussed and a brief research agenda is presented.« less

Securing mobile ad hoc networks using danger theory-based artificial immune algorithm.

PubMed

Abdelhaq, Maha; Alsaqour, Raed; Abdelhaq, Shawkat

2015-01-01

A mobile ad hoc network (MANET) is a set of mobile, decentralized, and self-organizing nodes that are used in special cases, such as in the military. MANET properties render the environment of this network vulnerable to different types of attacks, including black hole, wormhole and flooding-based attacks. Flooding-based attacks are one of the most dangerous attacks that aim to consume all network resources and thus paralyze the functionality of the whole network. Therefore, the objective of this paper is to investigate the capability of a danger theory-based artificial immune algorithm called the mobile dendritic cell algorithm (MDCA) to detect flooding-based attacks in MANETs. The MDCA applies the dendritic cell algorithm (DCA) to secure the MANET with additional improvements. The MDCA is tested and validated using Qualnet v7.1 simulation tool. This work also introduces a new simulation module for a flooding attack called the resource consumption attack (RCA) using Qualnet v7.1. The results highlight the high efficiency of the MDCA in detecting RCAs in MANETs.

Securing Mobile Ad Hoc Networks Using Danger Theory-Based Artificial Immune Algorithm

PubMed Central

2015-01-01

A mobile ad hoc network (MANET) is a set of mobile, decentralized, and self-organizing nodes that are used in special cases, such as in the military. MANET properties render the environment of this network vulnerable to different types of attacks, including black hole, wormhole and flooding-based attacks. Flooding-based attacks are one of the most dangerous attacks that aim to consume all network resources and thus paralyze the functionality of the whole network. Therefore, the objective of this paper is to investigate the capability of a danger theory-based artificial immune algorithm called the mobile dendritic cell algorithm (MDCA) to detect flooding-based attacks in MANETs. The MDCA applies the dendritic cell algorithm (DCA) to secure the MANET with additional improvements. The MDCA is tested and validated using Qualnet v7.1 simulation tool. This work also introduces a new simulation module for a flooding attack called the resource consumption attack (RCA) using Qualnet v7.1. The results highlight the high efficiency of the MDCA in detecting RCAs in MANETs. PMID:25946001

A suffix arrays based approach to semantic search in P2P systems

NASA Astrophysics Data System (ADS)

Shi, Qingwei; Zhao, Zheng; Bao, Hu

2007-09-01

Building a semantic search system on top of peer-to-peer (P2P) networks is becoming an attractive and promising alternative scheme for the reason of scalability, Data freshness and search cost. In this paper, we present a Suffix Arrays based algorithm for Semantic Search (SASS) in P2P systems, which generates a distributed Semantic Overlay Network (SONs) construction for full-text search in P2P networks. For each node through the P2P network, SASS distributes document indices based on a set of suffix arrays, by which clusters are created depending on words or phrases shared between documents, therefore, the search cost for a given query is decreased by only scanning semantically related documents. In contrast to recently announced SONs scheme designed by using metadata or predefined-class, SASS is an unsupervised approach for decentralized generation of SONs. SASS is also an incremental, linear time algorithm, which efficiently handle the problem of nodes update in P2P networks. Our simulation results demonstrate that SASS yields high search efficiency in dynamic environments.

Decentralized Quasi-Newton Methods

NASA Astrophysics Data System (ADS)

Eisen, Mark; Mokhtari, Aryan; Ribeiro, Alejandro

2017-05-01

We introduce the decentralized Broyden-Fletcher-Goldfarb-Shanno (D-BFGS) method as a variation of the BFGS quasi-Newton method for solving decentralized optimization problems. The D-BFGS method is of interest in problems that are not well conditioned, making first order decentralized methods ineffective, and in which second order information is not readily available, making second order decentralized methods impossible. D-BFGS is a fully distributed algorithm in which nodes approximate curvature information of themselves and their neighbors through the satisfaction of a secant condition. We additionally provide a formulation of the algorithm in asynchronous settings. Convergence of D-BFGS is established formally in both the synchronous and asynchronous settings and strong performance advantages relative to first order methods are shown numerically.

WindTalker: A P2P-Based Low-Latency Anonymous Communication Network

NASA Astrophysics Data System (ADS)

Zhang, Jia; Duan, Haixin; Liu, Wu; Wu, Jianping

Compared with traditional static anonymous communication networks, the P2P architecture can provide higher anonymity in communication. However, the P2P architecture also leads to more challenges, such as route, stability, trust and so on. In this paper, we present WindTalker, a P2P-based low-latency anonymous communication network. It is a pure decentralized mix network and can provide low-latency services which help users hide their real identity in communication. In order to ensure stability and reliability, WindTalker imports “seed nodes” to help a peer join in the P2P network and the peer nodes can use gossip-based protocol to exchange active information. Moreover, WindTalker uses layer encryption to ensure the information of relayed messages cannot be leaked. In addition, malicious nodes in the network are the major threat to anonymity of P2P anonymous communication, so WindTalker imports a trust mechanism which can help the P2P network exclude malicious nodes and optimize the strategy of peer discovery, tunnel construction, and relaying etc. in anonymous communications. We deploy peer nodes of WindTalker in our campus network to test reliability and analyze anonymity in theory. The network measurement and simulation analysis shows that WindTalker can provide low-latency and reliable anonymous communication services.

Antagonistic Phenomena in Network Dynamics

NASA Astrophysics Data System (ADS)

Motter, Adilson E.; Timme, Marc

2018-03-01

Recent research on the network modeling of complex systems has led to a convenient representation of numerous natural, social, and engineered systems that are now recognized as networks of interacting parts. Such systems can exhibit a wealth of phenomena that not only cannot be anticipated from merely examining their parts, as per the textbook definition of complexity, but also challenge intuition even when considered in the context of what is now known in network science. Here, we review the recent literature on two major classes of such phenomena that have far-reaching implications: (a) antagonistic responses to changes of states or parameters and (b) coexistence of seemingly incongruous behaviors or properties - both deriving from the collective and inherently decentralized nature of the dynamics. They include effects as diverse as negative compressibility in engineered materials, rescue interactions in biological networks, negative resistance in fluid networks, and the Braess paradox occurring across transport and supply networks. They also include remote synchronization, chimera states, and the converse of symmetry breaking in brain, power-grid, and oscillator networks as well as remote control in biological and bioinspired systems. By offering a unified view of these various scenarios, we suggest that they are representative of a yet broader class of unprecedented network phenomena that ought to be revealed and explained by future research.

Decentralization can help reduce deforestation when user groups engage with local government.

PubMed

Wright, Glenn D; Andersson, Krister P; Gibson, Clark C; Evans, Tom P

2016-12-27

Policy makers around the world tout decentralization as an effective tool in the governance of natural resources. Despite the popularity of these reforms, there is limited scientific evidence on the environmental effects of decentralization, especially in tropical biomes. This study presents evidence on the institutional conditions under which decentralization is likely to be successful in sustaining forests. We draw on common-pool resource theory to argue that the environmental impact of decentralization hinges on the ability of reforms to engage local forest users in the governance of forests. Using matching techniques, we analyze longitudinal field observations on both social and biophysical characteristics in a large number of local government territories in Bolivia (a country with a decentralized forestry policy) and Peru (a country with a much more centralized forestry policy). We find that territories with a decentralized forest governance structure have more stable forest cover, but only when local forest user groups actively engage with the local government officials. We provide evidence in support of a possible causal process behind these results: When user groups engage with the decentralized units, it creates a more enabling environment for effective local governance of forests, including more local government-led forest governance activities, fora for the resolution of forest-related conflicts, intermunicipal cooperation in the forestry sector, and stronger technical capabilities of the local government staff.

Quantitative Reevaluation of the Effects of Short- and Long-Term Removal of Descending Modulatory Inputs on the Pyloric Rhythm of the Crab, Cancer borealis1,2,3

PubMed Central

Hamood, Albert W.; Haddad, Sara A.; Otopalik, Adriane G.; Rosenbaum, Philipp

2015-01-01

Abstract The crustacean stomatogastric ganglion (STG) receives descending neuromodulatory inputs from three anterior ganglia: the paired commissural ganglia (CoGs), and the single esophageal ganglion (OG). In this paper, we provide the first detailed and quantitative analyses of the short- and long-term effects of removal of these descending inputs (decentralization) on the pyloric rhythm of the STG. Thirty minutes after decentralization, the mean frequency of the pyloric rhythm dropped from 1.20 Hz in control to 0.52 Hz. Whereas the relative phase of pyloric neuron activity was approximately constant across frequency in the controls, after decentralization this changed markedly. Nine control preparations kept for 5–6 d in vitro maintained pyloric rhythm frequencies close to their initial values. Nineteen decentralized preparations kept for 5–6 d dropped slightly in frequency from those seen at 30 min following decentralization, but then displayed stable activity over 6 d. Bouts of higher frequency activity were intermittently seen in both control and decentralized preparations, but the bouts began earlier and were more frequent in the decentralized preparations. Although the bouts may indicate that the removal of the modulatory inputs triggered changes in neuronal excitability, these changes did not produce obvious long-lasting changes in the frequency of the decentralized preparations. PMID:25914899

Decentralization can help reduce deforestation when user groups engage with local government

PubMed Central

Wright, Glenn D.; Gibson, Clark C.; Evans, Tom P.

2016-01-01

Policy makers around the world tout decentralization as an effective tool in the governance of natural resources. Despite the popularity of these reforms, there is limited scientific evidence on the environmental effects of decentralization, especially in tropical biomes. This study presents evidence on the institutional conditions under which decentralization is likely to be successful in sustaining forests. We draw on common-pool resource theory to argue that the environmental impact of decentralization hinges on the ability of reforms to engage local forest users in the governance of forests. Using matching techniques, we analyze longitudinal field observations on both social and biophysical characteristics in a large number of local government territories in Bolivia (a country with a decentralized forestry policy) and Peru (a country with a much more centralized forestry policy). We find that territories with a decentralized forest governance structure have more stable forest cover, but only when local forest user groups actively engage with the local government officials. We provide evidence in support of a possible causal process behind these results: When user groups engage with the decentralized units, it creates a more enabling environment for effective local governance of forests, including more local government-led forest governance activities, fora for the resolution of forest-related conflicts, intermunicipal cooperation in the forestry sector, and stronger technical capabilities of the local government staff. PMID:27956644

[Integrated delivery systems and other examples of collaboration among providers. SESPAS report, 2012].

PubMed

Vázquez, M Luisa; Vargas, Ingrid; Nuño, Roberto; Toro, Nuria

2012-03-01

Because of the steady increase in healthcare complexity, due to high specialization and the involvement of a number of services, as well as the increase in patients with chronic diseases and pluripathology, coordination has become a high-priority need in healthcare systems. The distinct regional services that comprise the decentralized Spanish National Health System have developed a number of experiences to improve collaboration among the providers involved in the healthcare process. The present article aims to analyze the experiences with integrated healthcare providers in Catalonia and the Basque Country and the chronic diseases programs of the latter. In Catalonia, which promoted the purchaser-provider split and maintained diversity in providers' ownership, organizations were slowly created that manage the provision of the healthcare continuum, known as integrated healthcare organizations (IHO). These organizations have evolved and, despite some common characteristics, they also show some differences, such as the emphasis on formal instruments or on coordination mechanisms and organic structures. This is also reflected in their results regarding culture and perceived coordination across the organization. In the Basque Country, in addition to the establishment of an IHO, a variety of integration experiences have been developed to improve the care of chronic diseases. Copyright © 2011 SESPAS. Published by Elsevier Espana. All rights reserved.

A molecular dynamics study of the atomic structure of (CaO)x(Al2O3)1-x glass with x = 0.625 close to the eutectic

NASA Astrophysics Data System (ADS)

Thomas, B. W. M.; Mead, R. N.; Mountjoy, G.

2006-05-01

Aluminate glasses are difficult to prepare as they do not contain traditional network formers, but they are promising materials for optical applications. The atomic structure of calcium aluminate glasses has been studied using several experimental techniques. The current study uses molecular dynamics to obtain a model of a (CaO)0.625(Al2O3)0.375 glass close to the eutectic. The glass consists of a tetrahedral alumina network with average network polymerization \\langle Q^{n}\\rangle of n = 3.3. Ca acts as a network modifier with average coordination of 6.2. Ca is typically coordinated to three bridging oxygens (Ob) and three non-bridging oxygens (Onb), with Ca-Onb bonds noticeably shorter than the Ca-Ob bonds. A new method of analysing modifier cation coordination is presented, which specifically shows the distribution of Ca coordination NCaO in terms of combinations of NCaOb and NCaOnb. Ob is most often coordinated to two Al plus two Ca, and Onb is most often coordinated to one Al plus three Ca. The typical coordinations of Ca, Ob, and Onb all have a noticeable similarity to those for the 5CaO·3Al2O3 crystal. The Ca-Ca distribution shows a clear similarity to that for (CaO)0.5(SiO2)0.5 glass, and this is attributed to the equal atomic number densities of Ca in these glasses.

Monitoring of stability of ASG-EUPOS network coordinates

NASA Astrophysics Data System (ADS)

Figurski, M.; Szafranek, K.; Wrona, M.

2009-04-01

ASG-EUPOS (Active Geodetic Network - European Position Determination System) is the national system of precise satellite positioning in Poland, which increases a density of regional and global GNSS networks and is widely used by public administration, national institutions, entrepreneurs and citizens (especially surveyors). In near future ASG-EUPOS is to take role of main national network. Control of proper activity of stations and realization of ETRS'89 is a necessity. User of the system needs to be sure that observations quality and coordinates accuracy are high enough. Coordinates of IGS (International GNSS Service) and EPN (European Permanent Network) stations are precisely determined and any changes are monitored all the time. Observations are verified before they are archived in regional and global databases. The same applies to ASG-EUPOS. This paper concerns standardization of GNSS observations from different stations (uniform adjustment), examination of solutions correctness according to IGS and EPN standards and stability of solutions and sites activity

Effects of Network Characteristics on Reaching the Payoff-Dominant Equilibrium in Coordination Games: A Simulation study.

PubMed

Buskens, Vincent; Snijders, Chris

2016-01-01

We study how payoffs and network structure affect reaching the payoff-dominant equilibrium in a [Formula: see text] coordination game that actors play with their neighbors in a network. Using an extensive simulation analysis of over 100,000 networks with 2-25 actors, we show that the importance of network characteristics is restricted to a limited part of the payoff space. In this part, we conclude that the payoff-dominant equilibrium is chosen more often if network density is larger, the network is more centralized, and segmentation of the network is smaller. Moreover, it is more likely that heterogeneity in behavior persists if the network is more segmented and less centralized. Persistence of heterogeneous behavior is not related to network density.

Strategies of Educational Decentralization: Key Questions and Core Issues.

ERIC Educational Resources Information Center

Hanson, E. Mark

1998-01-01

Explains key issues and forces that shape organization and management strategies of educational decentralization, using examples from Colombia, Venezuela, Argentina, Nicaragua, and Spain. Core decentralization issues include national and regional goals, planning, political stress, resource distribution, infrastructure development, and job…

The effect of decentralized behavioral decision making on system-level risk.

PubMed

Kaivanto, Kim

2014-12-01

Certain classes of system-level risk depend partly on decentralized lay decision making. For instance, an organization's network security risk depends partly on its employees' responses to phishing attacks. On a larger scale, the risk within a financial system depends partly on households' responses to mortgage sales pitches. Behavioral economics shows that lay decisionmakers typically depart in systematic ways from the normative rationality of expected utility (EU), and instead display heuristics and biases as captured in the more descriptively accurate prospect theory (PT). In turn, psychological studies show that successful deception ploys eschew direct logical argumentation and instead employ peripheral-route persuasion, manipulation of visceral emotions, urgency, and familiar contextual cues. The detection of phishing emails and inappropriate mortgage contracts may be framed as a binary classification task. Signal detection theory (SDT) offers the standard normative solution, formulated as an optimal cutoff threshold, for distinguishing between good/bad emails or mortgages. In this article, we extend SDT behaviorally by rederiving the optimal cutoff threshold under PT. Furthermore, we incorporate the psychology of deception into determination of SDT's discriminability parameter. With the neo-additive probability weighting function, the optimal cutoff threshold under PT is rendered unique under well-behaved sampling distributions, tractable in computation, and transparent in interpretation. The PT-based cutoff threshold is (i) independent of loss aversion and (ii) more conservative than the classical SDT cutoff threshold. Independently of any possible misalignment between individual-level and system-level misclassification costs, decentralized behavioral decisionmakers are biased toward underdetection, and system-level risk is consequently greater than in analyses predicated upon normative rationality. © 2014 Society for Risk Analysis.

The Global Outbreak Alert and Response Network

PubMed Central

Mackenzie, John S.; Drury, Patrick; Arthur, Ray R.; Ryan, Michael J.; Grein, Thomas; Slattery, Raphael; Suri, Sameera; Domingo, Christine Tiffany; Bejtullahu, Armand

2014-01-01

The Global Outbreak Alert and Response Network (GOARN) was established in 2000 as a network of technical institutions, research institutes, universities, international health organisations and technical networks willing to contribute and participate in internationally coordinated responses to infectious disease outbreaks. It reflected a recognition of the need to strengthen and coordinate rapid mobilisation of experts in responding to international outbreaks and to overcome the sometimes chaotic and fragmented operations characterising previous responses. The network partners agreed that the World Health Organization would coordinate the network and provide a secretariat, which would also function as the operational support team. The network has evolved to comprise 153 institutions/technical partners and 37 additional networks, the latter encompassing a further 355 members and has been directly involved in 137 missions to 79 countries, territories or areas. Future challenges will include supporting countries to achieve the capacity to detect and respond to outbreaks of international concern, as required by the International Health Regulations (2005). GOARN's increasing regional focus and expanding geographic composition will be central to meeting these challenges. The paper summarises some of network's achievements over the past 13 years and presents some of the future challenges. PMID:25186571

The global outbreak alert and response network.

PubMed

Mackenzie, John S; Drury, Patrick; Arthur, Ray R; Ryan, Michael J; Grein, Thomas; Slattery, Raphael; Suri, Sameera; Domingo, Christine Tiffany; Bejtullahu, Armand

2014-01-01

The Global Outbreak Alert and Response Network (GOARN) was established in 2000 as a network of technical institutions, research institutes, universities, international health organisations and technical networks willing to contribute and participate in internationally coordinated responses to infectious disease outbreaks. It reflected a recognition of the need to strengthen and coordinate rapid mobilisation of experts in responding to international outbreaks and to overcome the sometimes chaotic and fragmented operations characterising previous responses. The network partners agreed that the World Health Organization would coordinate the network and provide a secretariat, which would also function as the operational support team. The network has evolved to comprise 153 institutions/technical partners and 37 additional networks, the latter encompassing a further 355 members and has been directly involved in 137 missions to 79 countries, territories or areas. Future challenges will include supporting countries to achieve the capacity to detect and respond to outbreaks of international concern, as required by the International Health Regulations (2005). GOARN's increasing regional focus and expanding geographic composition will be central to meeting these challenges. The paper summarises some of network's achievements over the past 13 years and presents some of the future challenges.

Is decentralization good for logistics systems? Evidence on essential medicine logistics in Ghana and Guatemala.

PubMed

Bossert, Thomas J; Bowser, Diana M; Amenyah, Johnnie K

2007-03-01

Efficient logistics systems move essential medicines down the supply chain to the service delivery point, and then to the end user. Experts on logistics systems tend to see the supply chain as requiring centralized control to be most effective. However, many health reforms have involved decentralization, which experts fear has disrupted the supply chain and made systems less effective. There is no consensus on an appropriate methodology for assessing the effectiveness of decentralization in general, and only a few studies have attempted to address decentralization of logistics systems. This paper sets out a framework and methodology of a pioneering exploratory study that examines the experiences of decentralization in two countries, Guatemala and Ghana, and presents suggestive results of how decentralization affected the performance of their logistics systems. The analytical approach assessed decentralization using the principal author's 'decision space' approach, which defines decentralization as the degree of choice that local officials have over different health system functions. In this case the approach focused on 15 different logistics functions and measured the relationship between the degree of choice and indicators of performance for each of the functions. The results of both studies indicate that less choice (i.e. more centralized) was associated with better performance for two key functions (inventory control and information systems), while more choice (i.e. more decentralized) over planning and budgeting was associated with better performance. With different systems of procurement in Ghana and Guatemala, we found that a system with some elements of procurement that are centralized (selection of firms and prices fixed by national tender) was positively related in Guatemala but negatively related in Ghana, where a system of 'cash and carry' cost recovery allowed more local choice. The authors conclude that logistics systems can be effectively decentralized for some functions while others should remain centralized. These preliminary findings, however, should be subject to alternative methodologies to confirm the findings.

Utilizing semantic networks to database and retrieve generalized stochastic colored Petri nets

NASA Technical Reports Server (NTRS)

Farah, Jeffrey J.; Kelley, Robert B.

1992-01-01

Previous work has introduced the Planning Coordinator (PCOORD), a coordinator functioning within the hierarchy of the Intelligent Machine Mode. Within the structure of the Planning Coordinator resides the Primitive Structure Database (PSDB) functioning to provide the primitive structures utilized by the Planning Coordinator in the establishing of error recovery or on-line path plans. This report further explores the Primitive Structure Database and establishes the potential of utilizing semantic networks as a means of efficiently storing and retrieving the Generalized Stochastic Colored Petri Nets from which the error recovery plans are derived.

Do existing mechanisms contribute to improvements in care coordination across levels of care in health services networks? Opinions of the health personnel in Colombia and Brazil.

PubMed

Vargas, Ingrid; Mogollón-Pérez, Amparo Susana; De Paepe, Pierre; da Silva, Maria Rejane Ferreira; Unger, Jean Pierre; Vázquez, María Luisa

2015-05-29

The fragmentation of healthcare provision has given rise to a wide range of interventions within organizations to improve coordination across levels of care, primarily in high income countries but also in some middle and low-income countries. The aim is to analyze the use of coordination mechanisms in healthcare networks and its implications for the delivery of health care. This is studied from the perspective of health personnel in two countries with different health systems, Colombia and Brazil. A qualitative, exploratory and descriptive-interpretative study was conducted, based on a case study of healthcare networks in two municipalities in each country. Individual semi-structured interviews were conducted with a three stage theoretical sample of a) health (112) and administrative (66) professionals of different care levels, and b) managers of providers (42) and insurers (14). A thematic content analysis was conducted, segmented by cases, informant groups and themes. The results show that care coordination mechanisms are poorly implemented in general. However, the results are marginally better in certain segments of the Colombian networks analyzed (ambulatory centres with primary and secondary care co-location owned by or tied to the contributory scheme insurers, and public providers of the subsidized scheme); and in the network of the state capital in Brazil. Professionals point to numerous problems in the use of existing mechanisms, such as the insufficient recording of information in referral forms, low frequency and level of participation in shared clinical sessions, low adherence to the few available clinical guidelines and the lack of or inadequate referral of patients by the patient referral centres, particularly in the Brazilian networks. The absence or limited use of care coordination mechanisms leads, according to informants, to the inadequate follow-up of patients, interruptions in care and duplication of tests. Professionals use informal strategies to try to overcome these limitations. The results indicate not only the limited implementation of mechanisms for coordination across care levels, but also a limited use of existing mechanisms in the healthcare networks analyzed. This has a negative impact on coordination, efficiency and quality of care. Organizational changes are required in the networks and healthcare systems to address these problems.

Linear time-invariant controller design for two-channel decentralized control systems

NASA Technical Reports Server (NTRS)

Desoer, Charles A.; Gundes, A. Nazli

1987-01-01

This paper analyzes a linear time-invariant two-channel decentralized control system with a 2 x 2 strictly proper plant. It presents an algorithm for the algebraic design of a class of decentralized compensators which stabilize the given plant.