Congestion Pricing for Aircraft Pushback Slot Allocation

PubMed Central

Zhang, Yaping

2017-01-01

In order to optimize aircraft pushback management during rush hour, aircraft pushback slot allocation based on congestion pricing is explored while considering monetary compensation based on the quality of the surface operations. First, the concept of the “external cost of surface congestion” is proposed, and a quantitative study on the external cost is performed. Then, an aircraft pushback slot allocation model for minimizing the total surface cost is established. An improved discrete differential evolution algorithm is also designed. Finally, a simulation is performed on Xinzheng International Airport using the proposed model. By comparing the pushback slot control strategy based on congestion pricing with other strategies, the advantages of the proposed model and algorithm are highlighted. In addition to reducing delays and optimizing the delay distribution, the model and algorithm are better suited for use for actual aircraft pushback management during rush hour. Further, it is also observed they do not result in significant increases in the surface cost. These results confirm the effectiveness and suitability of the proposed model and algorithm. PMID:28114429

Implementation of the Algorithm for Congestion control in the Dynamic Circuit Network (DCN)

NASA Astrophysics Data System (ADS)

Nalamwar, H. S.; Ivanov, M. A.; Buddhawar, G. U.

2017-01-01

Transport Control Protocol (TCP) incast congestion happens when a number of senders work in parallel with the same server where the high bandwidth and low latency network problem occurs. For many data center network applications such as a search engine, heavy traffic is present on such a server. Incast congestion degrades the entire performance as packets are lost at a server side due to buffer overflow, and as a result, the response time becomes longer. In this work, we focus on TCP throughput, round-trip time (RTT), receive window and retransmission. Our method is based on the proactive adjust of the TCP receive window before the packet loss occurs. We aim to avoid the wastage of the bandwidth by adjusting its size as per the number of packets. To avoid the packet loss, the ICTCP algorithm has been implemented in the data center network (ToR).

Integrated Traffic Flow Management Decision Making

NASA Technical Reports Server (NTRS)

Grabbe, Shon R.; Sridhar, Banavar; Mukherjee, Avijit

2009-01-01

A generalized approach is proposed to support integrated traffic flow management decision making studies at both the U.S. national and regional levels. It can consider tradeoffs between alternative optimization and heuristic based models, strategic versus tactical flight controls, and system versus fleet preferences. Preliminary testing was accomplished by implementing thirteen unique traffic flow management models, which included all of the key components of the system and conducting 85, six-hour fast-time simulation experiments. These experiments considered variations in the strategic planning look-ahead times, the replanning intervals, and the types of traffic flow management control strategies. Initial testing indicates that longer strategic planning look-ahead times and re-planning intervals result in steadily decreasing levels of sector congestion for a fixed delay level. This applies when accurate estimates of the air traffic demand, airport capacities and airspace capacities are available. In general, the distribution of the delays amongst the users was found to be most equitable when scheduling flights using a heuristic scheduling algorithm, such as ration-by-distance. On the other hand, equity was the worst when using scheduling algorithms that took into account the number of seats aboard each flight. Though the scheduling algorithms were effective at alleviating sector congestion, the tactical rerouting algorithm was the primary control for avoiding en route weather hazards. Finally, the modeled levels of sector congestion, the number of weather incursions, and the total system delays, were found to be in fair agreement with the values that were operationally observed on both good and bad weather days.

Analysis of random drop for gateway congestion control. M.S. Thesis

NASA Technical Reports Server (NTRS)

Hashem, Emam Salaheddin

1989-01-01

Lately, the growing demand on the Internet has prompted the need for more effective congestion control policies. Currently No Gateway Policy is used to relieve and signal congestion, which leads to unfair service to the individual users and a degradation of overall network performance. Network simulation was used to illustrate the character of Internet congestion and its causes. A newly proposed gateway congestion control policy, called Random Drop, was considered as a promising solution to the pressing problem. Random Drop relieves resource congestion upon buffer overflow by choosing a random packet from the service queue to be dropped. The random choice should result in a drop distribution proportional to the bandwidth distribution among all contending TCP connections, thus applying the necessary fairness. Nonetheless, the simulation experiments demonstrate several shortcomings with this policy. Because Random Drop is a congestion control policy, which is not applied until congestion has already occurred, it usually results in a high drop rate that hurts too many connections including well-behaved ones. Even though the number of packets dropped is different from one connection to another depending on the buffer utilization upon overflow, the TCP recovery overhead is high enough to neutralize these differences, causing unfair congestion penalties. Besides, the drop distribution itself is an inaccurate representation of the average bandwidth distribution, missing much important information about the bandwidth utilization between buffer overflow events. A modification of Random Drop to do congestion avoidance by applying the policy early was also proposed. Early Random Drop has the advantage of avoiding the high drop rate of buffer overflow. The early application of the policy removes the pressure of congestion relief and allows more accurate signaling of congestion. To be used effectively, algorithms for the dynamic adjustment of the parameters of Early Random Drop to suite the current network load must still be developed.

Dynamic Capacity Allocation Algorithms for iNET Link Manager

DTIC Science & Technology

2014-05-01

algorithm that can better cope with severe congestion and misbehaving users and traffic flows. We compare the E-LM with the LM baseline algorithm (B-LM...capacity allocation algorithm that can better cope with severe congestion and misbehaving users and traffic flows. We compare the E-LM with the LM

A hierarchical framework for air traffic control

NASA Astrophysics Data System (ADS)

Roy, Kaushik

Air travel in recent years has been plagued by record delays, with over $8 billion in direct operating costs being attributed to 100 million flight delay minutes in 2007. Major contributing factors to delay include weather, congestion, and aging infrastructure; the Next Generation Air Transportation System (NextGen) aims to alleviate these delays through an upgrade of the air traffic control system. Changes to large-scale networked systems such as air traffic control are complicated by the need for coordinated solutions over disparate temporal and spatial scales. Individual air traffic controllers must ensure aircraft maintain safe separation locally with a time horizon of seconds to minutes, whereas regional plans are formulated to efficiently route flows of aircraft around weather and congestion on the order of every hour. More efficient control algorithms that provide a coordinated solution are required to safely handle a larger number of aircraft in a fixed amount of airspace. Improved estimation algorithms are also needed to provide accurate aircraft state information and situational awareness for human controllers. A hierarchical framework is developed to simultaneously solve the sometimes conflicting goals of regional efficiency and local safety. Careful attention is given in defining the interactions between the layers of this hierarchy. In this way, solutions to individual air traffic problems can be targeted and implemented as needed. First, the regional traffic flow management problem is posed as an optimization problem and shown to be NP-Hard. Approximation methods based on aggregate flow models are developed to enable real-time implementation of algorithms that reduce the impact of congestion and adverse weather. Second, the local trajectory design problem is solved using a novel slot-based sector model. This model is used to analyze sector capacity under varying traffic patterns, providing a more comprehensive understanding of how increased automation in NextGen will affect the overall performance of air traffic control. The dissertation also provides solutions to several key estimation problems that support corresponding control tasks. Throughout the development of these estimation algorithms, aircraft motion is modeled using hybrid systems, which encapsulate both the discrete flight mode of an aircraft and the evolution of continuous states such as position and velocity. The target-tracking problem is posed as one of hybrid state estimation, and two new algorithms are developed to exploit structure specific to aircraft motion, especially near airports. First, discrete mode evolution is modeled using state-dependent transitions, in which the likelihood of changing flight modes is dependent on aircraft state. Second, an estimator is designed for systems with limited mode changes, including arrival aircraft. Improved target tracking facilitates increased safety in collision avoidance and trajectory design problems. A multiple-target tracking and identity management algorithm is developed to improve situational awareness for controllers about multiple maneuvering targets in a congested region. Finally, tracking algorithms are extended to predict aircraft landing times; estimated time of arrival prediction is one example of important decision support information for air traffic control.

Models for IP/MPLS routing performance: convergence, fast reroute, and QoS impact

NASA Astrophysics Data System (ADS)

Choudhury, Gagan L.

2004-09-01

We show how to model the black-holing and looping of traffic during an Interior Gateway Protocol (IGP) convergence event at an IP network and how to significantly improve both the convergence time and packet loss duration through IGP parameter tuning and algorithmic improvement. We also explore some congestion avoidance and congestion control algorithms that can significantly improve stability of networks in the face of occasional massive control message storms. Specifically we show the positive impacts of prioritizing Hello and Acknowledgement packets and slowing down LSA generation and retransmission generation on detecting congestion in the network. For some types of video, voice signaling and circuit emulation applications it is necessary to reduce traffic loss durations following a convergence event to below 100 ms and we explore that using Fast Reroute algorithms based on Multiprotocol Label Switching Traffic Engineering (MPLS-TE) that effectively bypasses IGP convergence. We explore the scalability of primary and backup MPLS-TE tunnels where MPLS-TE domain is in the backbone-only or edge-to-edge. We also show how much extra backbone resource is needed to support Fast Reroute and how can that be reduced by taking advantage of Constrained Shortest Path (CSPF) routing of MPLS-TE and by reserving less than 100% of primary tunnel bandwidth during Fast Reroute.

Congestion control strategy on complex network with privilege traffic

NASA Astrophysics Data System (ADS)

Li, Shi-Bao; He, Ya; Liu, Jian-Hang; Zhang, Zhi-Gang; Huang, Jun-Wei

The congestion control of traffic is one of the most important studies in complex networks. In the previous congestion algorithms, all the network traffic is assumed to have the same priority, and the privilege of traffic is ignored. In this paper, a privilege and common traffic congestion control routing strategy (PCR) based on the different priority of traffic is proposed, which can be devised to cope with the different traffic congestion situations. We introduce the concept of privilege traffic in traffic dynamics for the first time and construct a new traffic model which taking into account requirements with different priorities. Besides, a new factor Ui is introduced by the theoretical derivation to characterize the interaction between different traffic routing selection, furthermore, Ui is related to the network throughput. Since the joint optimization among different kinds of traffic is accomplished by PCR, the maximum value of Ui can be significantly reduced and the network performance can be improved observably. The simulation results indicate that the network throughput with PCR has a better performance than the other strategies. Moreover, the network capacity is improved by 25% at least. Additionally, the network throughput is also influenced by privilege traffic number and traffic priority.

Reliable multicast protocol specifications flow control and NACK policy

NASA Technical Reports Server (NTRS)

Callahan, John R.; Montgomery, Todd L.; Whetten, Brian

1995-01-01

This appendix presents the flow and congestion control schemes recommended for RMP and a NACK policy based on the whiteboard tool. Because RMP uses a primarily NACK based error detection scheme, there is no direct feedback path through which receivers can signal losses through low buffer space or congestion. Reliable multicast protocols also suffer from the fact that throughput for a multicast group must be divided among the members of the group. This division is usually very dynamic in nature and therefore does not lend itself well to a priori determination. These facts have led the flow and congestion control schemes of RMP to be made completely orthogonal to the protocol specification. This allows several differing schemes to be used in different environments to produce the best results. As a default, a modified sliding window scheme based on previous algorithms are suggested and described below.

Improving traffic flow at a 2-to-1 lane reduction with wirelessly connected, adaptive cruise control vehicles

NASA Astrophysics Data System (ADS)

Davis, L. C.

2016-06-01

Wirelessly connected vehicles that exchange information about traffic conditions can reduce delays caused by congestion. At a 2-to-1 lane reduction, the improvement in flow past a bottleneck due to traffic with a random mixture of 40% connected vehicles is found to be 52%. Control is based on connected-vehicle-reported velocities near the bottleneck. In response to indications of congestion the connected vehicles, which are also adaptive cruise control vehicles, reduce their speed in slowdown regions. Early lane changes of manually driven vehicles from the terminated lane to the continuous lane are induced by the slowing connected vehicles. Self-organized congestion at the bottleneck is thus delayed or eliminated, depending upon the incoming flow magnitude. For the large majority of vehicles, travel times past the bottleneck are substantially reduced. Control is responsible for delaying the onset of congestion as the incoming flow increases. Adaptive cruise control increases the flow out of the congested state at the bottleneck. The nature of the congested state, when it occurs, appears to be similar under a variety of conditions. Typically 80-100 vehicles are approximately equally distributed between the lanes in the 500 m region prior to the end of the terminated lane. Without the adaptive cruise control capability, connected vehicles can delay the onset of congestion but do not increase the asymptotic flow past the bottleneck. Calculations are done using the Kerner-Klenov three-phase theory, stochastic discrete-time model for manual vehicles. The dynamics of the connected vehicles is given by a conventional adaptive cruise control algorithm plus commanded deceleration. Because time in the model for manual vehicles is discrete (one-second intervals), it is assumed that the acceleration of any vehicle immediately in front of a connected vehicle is constant during the time interval, thereby preserving the computational simplicity and speed of a discrete-time model.

Prediction based active ramp metering control strategy with mobility and safety assessment

NASA Astrophysics Data System (ADS)

Fang, Jie; Tu, Lili

2018-04-01

Ramp metering is one of the most direct and efficient motorway traffic flow management measures so as to improve traffic conditions. However, owing to short of traffic conditions prediction, in earlier studies, the impact on traffic flow dynamics of the applied RM control was not quantitatively evaluated. In this study, a RM control algorithm adopting Model Predictive Control (MPC) framework to predict and assess future traffic conditions, which taking both the current traffic conditions and the RM-controlled future traffic states into consideration, was presented. The designed RM control algorithm targets at optimizing the network mobility and safety performance. The designed algorithm is evaluated in a field-data-based simulation. Through comparing the presented algorithm controlled scenario with the uncontrolled scenario, it was proved that the proposed RM control algorithm can effectively relieve the congestion of traffic network with no significant compromises in safety aspect.

Agent-based traffic management and reinforcement learning in congested intersection network.

DOT National Transportation Integrated Search

2012-08-01

This study evaluates the performance of traffic control systems based on reinforcement learning (RL), also called approximate dynamic programming (ADP). Two algorithms have been selected for testing: 1) Q-learning and 2) approximate dynamic programmi...

Developing an area-wide system for coordinated ramp meter control.

DOT National Transportation Integrated Search

2008-12-01

Ramp metering has been broadly accepted and deployed as an effective countermeasure : against both recurrent and non-recurrent congestion on freeways. However, many current ramp : metering algorithms tend to improve only freeway travels using local d...

Adapting End Host Congestion Control for Mobility

NASA Technical Reports Server (NTRS)

Eddy, Wesley M.; Swami, Yogesh P.

2005-01-01

Network layer mobility allows transport protocols to maintain connection state, despite changes in a node's physical location and point of network connectivity. However, some congestion-controlled transport protocols are not designed to deal with these rapid and potentially significant path changes. In this paper we demonstrate several distinct problems that mobility-induced path changes can create for TCP performance. Our premise is that mobility events indicate path changes that require re-initialization of congestion control state at both connection end points. We present the application of this idea to TCP in the form of a simple solution (the Lightweight Mobility Detection and Response algorithm, that has been proposed in the IETF), and examine its effectiveness. In general, we find that the deficiencies presented are both relatively easily and painlessly fixed using this solution. We also find that this solution has the counter-intuitive property of being both more friendly to competing traffic, and simultaneously more aggressive in utilizing newly available capacity than unmodified TCP.

Packets Distributing Evolutionary Algorithm Based on PSO for Ad Hoc Network

NASA Astrophysics Data System (ADS)

Xu, Xiao-Feng

2018-03-01

Wireless communication network has such features as limited bandwidth, changeful channel and dynamic topology, etc. Ad hoc network has lots of difficulties in accessing control, bandwidth distribution, resource assign and congestion control. Therefore, a wireless packets distributing Evolutionary algorithm based on PSO (DPSO)for Ad Hoc Network is proposed. Firstly, parameters impact on performance of network are analyzed and researched to obtain network performance effective function. Secondly, the improved PSO Evolutionary Algorithm is used to solve the optimization problem from local to global in the process of network packets distributing. The simulation results show that the algorithm can ensure fairness and timeliness of network transmission, as well as improve ad hoc network resource integrated utilization efficiency.

A robust fractional-order PID controller design based on active queue management for TCP network

NASA Astrophysics Data System (ADS)

Hamidian, Hamideh; Beheshti, Mohammad T. H.

2018-01-01

In this paper, a robust fractional-order controller is designed to control the congestion in transmission control protocol (TCP) networks with time-varying parameters. Fractional controllers can increase the stability and robustness. Regardless of advantages of fractional controllers, they are still not common in congestion control in TCP networks. The network parameters are time-varying, so the robust stability is important in congestion controller design. Therefore, we focused on the robust controller design. The fractional PID controller is developed based on active queue management (AQM). D-partition technique is used. The most important property of designed controller is the robustness to the time-varying parameters of the TCP network. The vertex quasi-polynomials of the closed-loop characteristic equation are obtained, and the stability boundaries are calculated for each vertex quasi-polynomial. The intersection of all stability regions is insensitive to network parameter variations, and results in robust stability of TCP/AQM system. NS-2 simulations show that the proposed algorithm provides a stable queue length. Moreover, simulations show smaller oscillations of the queue length and less packet drop probability for FPID compared to PI and PID controllers. We can conclude from NS-2 simulations that the average packet loss probability variations are negligible when the network parameters change.

Automated Flight Routing Using Stochastic Dynamic Programming

NASA Technical Reports Server (NTRS)

Ng, Hok K.; Morando, Alex; Grabbe, Shon

2010-01-01

Airspace capacity reduction due to convective weather impedes air traffic flows and causes traffic congestion. This study presents an algorithm that reroutes flights in the presence of winds, enroute convective weather, and congested airspace based on stochastic dynamic programming. A stochastic disturbance model incorporates into the reroute design process the capacity uncertainty. A trajectory-based airspace demand model is employed for calculating current and future airspace demand. The optimal routes minimize the total expected traveling time, weather incursion, and induced congestion costs. They are compared to weather-avoidance routes calculated using deterministic dynamic programming. The stochastic reroutes have smaller deviation probability than the deterministic counterpart when both reroutes have similar total flight distance. The stochastic rerouting algorithm takes into account all convective weather fields with all severity levels while the deterministic algorithm only accounts for convective weather systems exceeding a specified level of severity. When the stochastic reroutes are compared to the actual flight routes, they have similar total flight time, and both have about 1% of travel time crossing congested enroute sectors on average. The actual flight routes induce slightly less traffic congestion than the stochastic reroutes but intercept more severe convective weather.

Research in Network Management Techniques for Tactical Data Communications Network.

DTIC Science & Technology

1982-09-01

the control period. Research areas include Packet Network modelling, adaptive network routing, network design algorithms, network design techniques...contro!lers are designed to perform their limited tasks optimally. For the dynamic routing problem considered here, the local controllers are node...feedback to finding in optimum stead-o-state routing (static strategies) under non - control which can be easily implemented in real time. congested

Network traffic behaviour near phase transition point

NASA Astrophysics Data System (ADS)

Lawniczak, A. T.; Tang, X.

2006-03-01

We explore packet traffic dynamics in a data network model near phase transition point from free flow to congestion. The model of data network is an abstraction of the Network Layer of the OSI (Open Systems Interconnect) Reference Model of packet switching networks. The Network Layer is responsible for routing packets across the network from their sources to their destinations and for control of congestion in data networks. Using the model we investigate spatio-temporal packets traffic dynamics near the phase transition point for various network connection topologies, and static and adaptive routing algorithms. We present selected simulation results and analyze them.

A Rate-Based Congestion Control Algorithm for the SURAP 4 Packet Radio Architecture (SRNTN-72)

DTIC Science & Technology

1990-01-01

factor, one packet. as at connection initialization. However. these TCP enhancements do not solve the fairness problem. The slow start algorithm ma...and signal interference (including lamming) and by the delavs demanded b% the hink -layer protocols in the absence of contention for resources at the...values. This role would be redundant if bits-per-second rations used measurements of packet duration to determine how fast to decrease, at the expense of

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.

Real-time adaptive aircraft scheduling

NASA Technical Reports Server (NTRS)

Kolitz, Stephan E.; Terrab, Mostafa

1990-01-01

One of the most important functions of any air traffic management system is the assignment of ground-holding times to flights, i.e., the determination of whether and by how much the take-off of a particular aircraft headed for a congested part of the air traffic control (ATC) system should be postponed in order to reduce the likelihood and extent of airborne delays. An analysis is presented for the fundamental case in which flights from many destinations must be scheduled for arrival at a single congested airport; the formulation is also useful in scheduling the landing of airborne flights within the extended terminal area. A set of approaches is described for addressing a deterministic and a probabilistic version of this problem. For the deterministic case, where airport capacities are known and fixed, several models were developed with associated low-order polynomial-time algorithms. For general delay cost functions, these algorithms find an optimal solution. Under a particular natural assumption regarding the delay cost function, an extremely fast (O(n ln n)) algorithm was developed. For the probabilistic case, using an estimated probability distribution of airport capacities, a model was developed with an associated low-order polynomial-time heuristic algorithm with useful properties.

Random early detection for congestion avoidance in wired networks: a discretized pursuit learning-automata-like solution.

PubMed

Misra, Sudip; Oommen, B John; Yanamandra, Sreekeerthy; Obaidat, Mohammad S

2010-02-01

In this paper, we present a learning-automata-like The reason why the mechanism is not a pure LA, but rather why it yet mimics one, will be clarified in the body of this paper. (LAL) mechanism for congestion avoidance in wired networks. Our algorithm, named as LAL Random Early Detection (LALRED), is founded on the principles of the operations of existing RED congestion-avoidance mechanisms, augmented with a LAL philosophy. The primary objective of LALRED is to optimize the value of the average size of the queue used for congestion avoidance and to consequently reduce the total loss of packets at the queue. We attempt to achieve this by stationing a LAL algorithm at the gateways and by discretizing the probabilities of the corresponding actions of the congestion-avoidance algorithm. At every time instant, the LAL scheme, in turn, chooses the action that possesses the maximal ratio between the number of times the chosen action is rewarded and the number of times that it has been chosen. In LALRED, we simultaneously increase the likelihood of the scheme converging to the action, which minimizes the number of packet drops at the gateway. Our approach helps to improve the performance of congestion avoidance by adaptively minimizing the queue-loss rate and the average queue size. Simulation results obtained using NS2 establish the improved performance of LALRED over the traditional RED methods which were chosen as the benchmarks for performance comparison purposes.

Evaluation of Swift Start TCP in Long-Delay Environment

NASA Technical Reports Server (NTRS)

Lawas-Grodek, Frances J.; Tran, Diepchi T.

2004-01-01

This report presents the test results of the Swift Start algorithm in single-flow and multiple-flow testbeds under the effects of high propagation delays, various slow bottlenecks, and small queue sizes. Although this algorithm estimates capacity and implements packet pacing, the findings were that in a heavily congested link, the Swift Start algorithm will not be applicable. The reason is that the bottleneck estimation is falsely influenced by timeouts induced by retransmissions and the expiration of delayed acknowledgment (ACK) timers, thus causing the modified Swift Start code to fall back to regular transmission control protocol (TCP).

Overload Control for Signaling Congestion of Machine Type Communications in 3GPP Networks

PubMed Central

Lu, Zhaoming; Pan, Qi; Wang, Luhan; Wen, Xiangming

2016-01-01

Because of the limited resources on radio access channels of third generation partnership projection (3GPP) network, one of the most challenging tasks posted by 3GPP cellular-based machine type communications (MTC) is congestion due to massive requests for connection to radio access network (RAN). In this paper, an overload control algorithm in 3GPP RAN is proposed, which proactively disperses the simultaneous access attempts in evenly distributed time window. Through periodic reservation strategy, massive access requests of MTC devices are dispersed in time, which reduces the probability of confliction of signaling. By the compensation and prediction mechanism, each device can communicate with MTC server with dynamic load of air interface. Numerical results prove that proposed method makes MTC applications friendly to 3GPP cellular network. PMID:27936011

Overload Control for Signaling Congestion of Machine Type Communications in 3GPP Networks.

PubMed

Lu, Zhaoming; Pan, Qi; Wang, Luhan; Wen, Xiangming

2016-01-01

Because of the limited resources on radio access channels of third generation partnership projection (3GPP) network, one of the most challenging tasks posted by 3GPP cellular-based machine type communications (MTC) is congestion due to massive requests for connection to radio access network (RAN). In this paper, an overload control algorithm in 3GPP RAN is proposed, which proactively disperses the simultaneous access attempts in evenly distributed time window. Through periodic reservation strategy, massive access requests of MTC devices are dispersed in time, which reduces the probability of confliction of signaling. By the compensation and prediction mechanism, each device can communicate with MTC server with dynamic load of air interface. Numerical results prove that proposed method makes MTC applications friendly to 3GPP cellular network.

Autonomous Distributed Congestion Control Scheme in WCDMA Network

NASA Astrophysics Data System (ADS)

Ahmad, Hafiz Farooq; Suguri, Hiroki; Choudhary, Muhammad Qaisar; Hassan, Ammar; Liaqat, Ali; Khan, Muhammad Umer

Wireless technology has become widely popular and an important means of communication. A key issue in delivering wireless services is the problem of congestion which has an adverse impact on the Quality of Service (QoS), especially timeliness. Although a lot of work has been done in the context of RRM (Radio Resource Management), the deliverance of quality service to the end user still remains a challenge. Therefore there is need for a system that provides real-time services to the users through high assurance. We propose an intelligent agent-based approach to guarantee a predefined Service Level Agreement (SLA) with heterogeneous user requirements for appropriate bandwidth allocation in QoS sensitive cellular networks. The proposed system architecture exploits Case Based Reasoning (CBR) technique to handle RRM process of congestion management. The system accomplishes predefined SLA through the use of Retrieval and Adaptation Algorithm based on CBR case library. The proposed intelligent agent architecture gives autonomy to Radio Network Controller (RNC) or Base Station (BS) in accepting, rejecting or buffering a connection request to manage system bandwidth. Instead of simply blocking the connection request as congestion hits the system, different buffering durations are allocated to diverse classes of users based on their SLA. This increases the opportunity of connection establishment and reduces the call blocking rate extensively in changing environment. We carry out simulation of the proposed system that verifies efficient performance for congestion handling. The results also show built-in dynamism of our system to cater for variety of SLA requirements.

Load Balancing in Distributed Web Caching: A Novel Clustering Approach

NASA Astrophysics Data System (ADS)

Tiwari, R.; Kumar, K.; Khan, G.

2010-11-01

The World Wide Web suffers from scaling and reliability problems due to overloaded and congested proxy servers. Caching at local proxy servers helps, but cannot satisfy more than a third to half of requests; more requests are still sent to original remote origin servers. In this paper we have developed an algorithm for Distributed Web Cache, which incorporates cooperation among proxy servers of one cluster. This algorithm uses Distributed Web Cache concepts along with static hierarchies with geographical based clusters of level one proxy server with dynamic mechanism of proxy server during the congestion of one cluster. Congestion and scalability problems are being dealt by clustering concept used in our approach. This results in higher hit ratio of caches, with lesser latency delay for requested pages. This algorithm also guarantees data consistency between the original server objects and the proxy cache objects.

Understanding the topological characteristics and flow complexity of urban traffic congestion

NASA Astrophysics Data System (ADS)

Wen, Tzai-Hung; Chin, Wei-Chien-Benny; Lai, Pei-Chun

2017-05-01

For a growing number of developing cities, the capacities of streets cannot meet the rapidly growing demand of cars, causing traffic congestion. Understanding the spatial-temporal process of traffic flow and detecting traffic congestion are important issues associated with developing sustainable urban policies to resolve congestion. Therefore, the objective of this study is to propose a flow-based ranking algorithm for investigating traffic demands in terms of the attractiveness of street segments and flow complexity of the street network based on turning probability. Our results show that, by analyzing the topological characteristics of streets and volume data for a small fraction of street segments in Taipei City, the most congested segments of the city were identified successfully. The identified congested segments are significantly close to the potential congestion zones, including the officially announced most congested streets, the segments with slow moving speeds at rush hours, and the areas near significant landmarks. The identified congested segments also captured congestion-prone areas concentrated in the business districts and industrial areas of the city. Identifying the topological characteristics and flow complexity of traffic congestion provides network topological insights for sustainable urban planning, and these characteristics can be used to further understand congestion propagation.

Packet Traffic Dynamics Near Onset of Congestion in Data Communication Network Model

NASA Astrophysics Data System (ADS)

Lawniczak, A. T.; Tang, X.

2006-05-01

The dominant technology of data communication networks is the Packet Switching Network (PSN). It is a complex technology organized as various hierarchical layers according to the International Standard Organization (ISO) Open Systems Interconnect (OSI) Reference Model. The Network Layer of the ISO OSI Reference Model is responsible for delivering packets from their sources to their destinations and for dealing with congestion if it arises in a network. Thus, we focus on this layer and present an abstraction of the Network Layer of the ISO OSI Reference Model. Using this abstraction we investigate how onset of traffic congestion is affected for various routing algorithms by changes in network connection topology. We study how aggregate measures of network performance depend on network connection topology and routing. We explore packets traffic spatio-temporal dynamics near the phase transition point from free flow to congestion for various network connection topologies and routing algorithms. We consider static and adaptive routings. We present selected simulation results.

Analysis of Random Drop for Gateway Congestion Control

DTIC Science & Technology

1989-11-01

effective congest)on control policies. Currently No Gateway Policy is used to relieve and signal congestion, which leads to unfair service to the...early application of the policy removes the pressure of congestion relief and allows more accurate signaling of congestion. ’ To be used effectively ...prompted the need for more effective congestion control policies. Currently No Gateway Policy is used to relieve and signal congestion, which leads to

An End-to-End Loss Discrimination Scheme for Multimedia Transmission over Wireless IP Networks

NASA Astrophysics Data System (ADS)

Zhao, Hai-Tao; Dong, Yu-Ning; Li, Yang

As the rapid growth of wireless IP networks, wireless IP access networks have a lot of potential applications in a variety of fields in civilian and military environments. Many of these applications, such as realtime audio/video streaming, will require some form of end-to-end QoS assurance. In this paper, an algorithm WMPLD (Wireless Multimedia Packet Loss Discrimination) is proposed for multimedia transmission control over wired-wireless hybrid IP networks. The relationship between packet length and packet loss rate in the Gilbert wireless error model is investigated. Furthermore, the algorithm can detect the nature of packet losses by sending large and small packets alternately, and control the sending rate of nodes. In addition, by means of updating factor K, this algorithm can adapt to the changes of network states quickly. Simulation results show that, compared to previous algorithms, WMPLD algorithm can improve the networks throughput as well as reduce the congestion loss rate in various situations.

Scalable analysis of nonlinear systems using convex optimization

NASA Astrophysics Data System (ADS)

Papachristodoulou, Antonis

In this thesis, we investigate how convex optimization can be used to analyze different classes of nonlinear systems at various scales algorithmically. The methodology is based on the construction of appropriate Lyapunov-type certificates using sum of squares techniques. After a brief introduction on the mathematical tools that we will be using, we turn our attention to robust stability and performance analysis of systems described by Ordinary Differential Equations. A general framework for constrained systems analysis is developed, under which stability of systems with polynomial, non-polynomial vector fields and switching systems, as well estimating the region of attraction and the L2 gain can be treated in a unified manner. We apply our results to examples from biology and aerospace. We then consider systems described by Functional Differential Equations (FDEs), i.e., time-delay systems. Their main characteristic is that they are infinite dimensional, which complicates their analysis. We first show how the complete Lyapunov-Krasovskii functional can be constructed algorithmically for linear time-delay systems. Then, we concentrate on delay-independent and delay-dependent stability analysis of nonlinear FDEs using sum of squares techniques. An example from ecology is given. The scalable stability analysis of congestion control algorithms for the Internet is investigated next. The models we use result in an arbitrary interconnection of FDE subsystems, for which we require that stability holds for arbitrary delays, network topologies and link capacities. Through a constructive proof, we develop a Lyapunov functional for FAST---a recently developed network congestion control scheme---so that the Lyapunov stability properties scale with the system size. We also show how other network congestion control schemes can be analyzed in the same way. Finally, we concentrate on systems described by Partial Differential Equations. We show that axially constant perturbations of the Navier-Stokes equations for Hagen-Poiseuille flow are globally stable, even though the background noise is amplified as R3 where R is the Reynolds number, giving a 'robust yet fragile' interpretation. We also propose a sum of squares methodology for the analysis of systems described by parabolic PDEs. We conclude this work with an account for future research.

An Improved Simulated Annealing Technique for Enhanced Mobility in Smart Cities.

PubMed

Amer, Hayder; Salman, Naveed; Hawes, Matthew; Chaqfeh, Moumena; Mihaylova, Lyudmila; Mayfield, Martin

2016-06-30

Vehicular traffic congestion is a significant problem that arises in many cities. This is due to the increasing number of vehicles that are driving on city roads of limited capacity. The vehicular congestion significantly impacts travel distance, travel time, fuel consumption and air pollution. Avoidance of traffic congestion and providing drivers with optimal paths are not trivial tasks. The key contribution of this work consists of the developed approach for dynamic calculation of optimal traffic routes. Two attributes (the average travel speed of the traffic and the roads' length) are utilized by the proposed method to find the optimal paths. The average travel speed values can be obtained from the sensors deployed in smart cities and communicated to vehicles via the Internet of Vehicles and roadside communication units. The performance of the proposed algorithm is compared to three other algorithms: the simulated annealing weighted sum, the simulated annealing technique for order preference by similarity to the ideal solution and the Dijkstra algorithm. The weighted sum and technique for order preference by similarity to the ideal solution methods are used to formulate different attributes in the simulated annealing cost function. According to the Sheffield scenario, simulation results show that the improved simulated annealing technique for order preference by similarity to the ideal solution method improves the traffic performance in the presence of congestion by an overall average of 19.22% in terms of travel time, fuel consumption and CO₂ emissions as compared to other algorithms; also, similar performance patterns were achieved for the Birmingham test scenario.

An Improved Simulated Annealing Technique for Enhanced Mobility in Smart Cities

PubMed Central

Amer, Hayder; Salman, Naveed; Hawes, Matthew; Chaqfeh, Moumena; Mihaylova, Lyudmila; Mayfield, Martin

2016-01-01

Vehicular traffic congestion is a significant problem that arises in many cities. This is due to the increasing number of vehicles that are driving on city roads of limited capacity. The vehicular congestion significantly impacts travel distance, travel time, fuel consumption and air pollution. Avoidance of traffic congestion and providing drivers with optimal paths are not trivial tasks. The key contribution of this work consists of the developed approach for dynamic calculation of optimal traffic routes. Two attributes (the average travel speed of the traffic and the roads’ length) are utilized by the proposed method to find the optimal paths. The average travel speed values can be obtained from the sensors deployed in smart cities and communicated to vehicles via the Internet of Vehicles and roadside communication units. The performance of the proposed algorithm is compared to three other algorithms: the simulated annealing weighted sum, the simulated annealing technique for order preference by similarity to the ideal solution and the Dijkstra algorithm. The weighted sum and technique for order preference by similarity to the ideal solution methods are used to formulate different attributes in the simulated annealing cost function. According to the Sheffield scenario, simulation results show that the improved simulated annealing technique for order preference by similarity to the ideal solution method improves the traffic performance in the presence of congestion by an overall average of 19.22% in terms of travel time, fuel consumption and CO2 emissions as compared to other algorithms; also, similar performance patterns were achieved for the Birmingham test scenario. PMID:27376289

Efficient algorithm for locating and sizing series compensation devices in large power transmission grids: I. Model implementation

NASA Astrophysics Data System (ADS)

Frolov, Vladimir; Backhaus, Scott; Chertkov, Misha

2014-10-01

We explore optimization methods for planning the placement, sizing and operations of flexible alternating current transmission system (FACTS) devices installed to relieve transmission grid congestion. We limit our selection of FACTS devices to series compensation (SC) devices that can be represented by modification of the inductance of transmission lines. Our master optimization problem minimizes the l1 norm of the inductance modification subject to the usual line thermal-limit constraints. We develop heuristics that reduce this non-convex optimization to a succession of linear programs (LP) that are accelerated further using cutting plane methods. The algorithm solves an instance of the MatPower Polish Grid model (3299 lines and 2746 nodes) in 40 seconds per iteration on a standard laptop—a speed that allows the sizing and placement of a family of SC devices to correct a large set of anticipated congestions. We observe that our algorithm finds feasible solutions that are always sparse, i.e., SC devices are placed on only a few lines. In a companion manuscript, we demonstrate our approach on realistically sized networks that suffer congestion from a range of causes, including generator retirement. In this manuscript, we focus on the development of our approach, investigate its structure on a small test system subject to congestion from uniform load growth, and demonstrate computational efficiency on a realistically sized network.

Efficient algorithm for locating and sizing series compensation devices in large power transmission grids: I. Model implementation

DOE PAGES

Frolov, Vladimir; Backhaus, Scott; Chertkov, Misha

2014-10-24

We explore optimization methods for planning the placement, sizing and operations of Flexible Alternating Current Transmission System (FACTS) devices installed to relieve transmission grid congestion. We limit our selection of FACTS devices to Series Compensation (SC) devices that can be represented by modification of the inductance of transmission lines. Our master optimization problem minimizes the l 1 norm of the inductance modification subject to the usual line thermal-limit constraints. We develop heuristics that reduce this non-convex optimization to a succession of Linear Programs (LP) which are accelerated further using cutting plane methods. The algorithm solves an instance of the MatPowermore » Polish Grid model (3299 lines and 2746 nodes) in 40 seconds per iteration on a standard laptop—a speed up that allows the sizing and placement of a family of SC devices to correct a large set of anticipated congestions. We observe that our algorithm finds feasible solutions that are always sparse, i.e., SC devices are placed on only a few lines. In a companion manuscript, we demonstrate our approach on realistically-sized networks that suffer congestion from a range of causes including generator retirement. In this manuscript, we focus on the development of our approach, investigate its structure on a small test system subject to congestion from uniform load growth, and demonstrate computational efficiency on a realistically-sized network.« less

Dynamic traffic assignment : genetic algorithms approach

DOT National Transportation Integrated Search

1997-01-01

Real-time route guidance is a promising approach to alleviating congestion on the nations highways. A dynamic traffic assignment model is central to the development of guidance strategies. The artificial intelligence technique of genetic algorithm...

Pricing and location decisions in multi-objective facility location problem with M/M/m/k queuing systems

NASA Astrophysics Data System (ADS)

Tavakkoli-Moghaddam, Reza; Vazifeh-Noshafagh, Samira; Taleizadeh, Ata Allah; Hajipour, Vahid; Mahmoudi, Amin

2017-01-01

This article presents a new multi-objective model for a facility location problem with congestion and pricing policies. This model considers situations in which immobile service facilities are congested by a stochastic demand following M/M/m/k queues. The presented model belongs to the class of mixed-integer nonlinear programming models and NP-hard problems. To solve such a hard model, a new multi-objective optimization algorithm based on a vibration theory, namely multi-objective vibration damping optimization (MOVDO), is developed. In order to tune the algorithms parameters, the Taguchi approach using a response metric is implemented. The computational results are compared with those of the non-dominated ranking genetic algorithm and non-dominated sorting genetic algorithm. The outputs demonstrate the robustness of the proposed MOVDO in large-sized problems.

Autonomous Congestion Control in Delay-Tolerant Networks

NASA Technical Reports Server (NTRS)

Burleigh, Scott; Jennings, Esther; Schoolcraft, Joshua

2006-01-01

Congestion control is an important feature that directly affects network performance. Network congestion may cause loss of data or long delays. Although this problem has been studied extensively in the Internet, the solutions for Internet congestion control do not apply readily to challenged network environments such as Delay Tolerant Networks (DTN) where end-to-end connectivity may not exist continuously and latency can be high. In DTN, end-to-end rate control is not feasible. This calls for congestion control mechanisms where the decisions can be made autonomously with local information only. We use an economic pricing model and propose a rule-based congestion control mechanism where each router can autonomously decide on whether to accept a bundle (data) based on local information such as available storage and the value and risk of accepting the bundle (derived from historical statistics). Preliminary experimental results show that this congestion control mechanism can protect routers from resource depletion without loss of data.

Highly Dynamic and Adaptive Traffic Congestion Avoidance in Real-Time Inspired by Honey Bee Behavior

NASA Astrophysics Data System (ADS)

Wedde, Horst F.; Lehnhoff, Sebastian; van Bonn, Bernhard; Bay, Z.; Becker, S.; Böttcher, S.; Brunner, C.; Büscher, A.; Fürst, T.; Lazarescu, A. M.; Rotaru, E.; Senge, S.; Steinbach, B.; Yilmaz, F.; Zimmermann, T.

Traffic congestions have become a major problem in metropolitan areas world-wide, within and between cities, to an extent where they make driving and transportation times largely unpredictable. Due to the highly dynamic character of congestion building and dissolving this phenomenon appears even to resist a formal treatment. Static approaches, and even more their global management, have proven counterproductive in practice. Given the latest progress in VANET technology and the remarkable commercially driven efforts like in the European C2C consortium, or the VSC Project in the US, allow meanwhile to tackle various aspects of traffic regulation through VANET communication. In this paper we introduce a novel, completely decentralized multi-agent routing algorithm (termed BeeJamA) which we have derived from the foraging behavior of honey bees. It is highly dynamic, adaptive, robust, and scalable, and it allows for both avoiding congestions, and minimizing traveling times to individual destinations. Vehicle guidance is provided well ahead of every intersection, depending on the individual speeds. Thus strict deadlines are imposed on, and respected by, the BeeJamA algorithm. We report on extensive simulation experiments which show the superior performance of BeeJamA over conventional approaches.

Stochastic Prediction and Feedback Control of Router Queue Size in a Virtual Network Environment

DTIC Science & Technology

2014-09-18

predictor equations, while the update equations for measurement can be thought of as corrector equations. 11 2.3.1.1 Predict Equations In the... Adaptive Filters and Self -Learning Systems. Springer London, 2005. [11] Zarchan, P., and Musoff, H. Fundamentals of Kalman filtering: A Practical...iv AFIT-ENG-T-14-S-10 Abstract Modern congestion and routing management algorithms work well for networks with static topologies and moderate

Active noise control for infant incubators.

PubMed

Yu, Xun; Gujjula, Shruthi; Kuo, Sen M

2009-01-01

This paper presents an active noise control system for infant incubators. Experimental results show that global noise reduction can be achieved for infant incubator ANC systems. An audio-integration algorithm is presented to introduce a healthy audio (intrauterine) sound with the ANC system to mask the residual noise and soothe the infant. Carbon nanotube based transparent thin film speaker is also introduced in this paper as the actuator for the ANC system to generate the destructive secondary sound, which can significantly save the congested incubator space and without blocking the view of doctors and nurses.

Design and implementation of streaming media server cluster based on FFMpeg.

PubMed

Zhao, Hong; Zhou, Chun-long; Jin, Bao-zhao

2015-01-01

Poor performance and network congestion are commonly observed in the streaming media single server system. This paper proposes a scheme to construct a streaming media server cluster system based on FFMpeg. In this scheme, different users are distributed to different servers according to their locations and the balance among servers is maintained by the dynamic load-balancing algorithm based on active feedback. Furthermore, a service redirection algorithm is proposed to improve the transmission efficiency of streaming media data. The experiment results show that the server cluster system has significantly alleviated the network congestion and improved the performance in comparison with the single server system.

Design and Implementation of Streaming Media Server Cluster Based on FFMpeg

PubMed Central

Zhao, Hong; Zhou, Chun-long; Jin, Bao-zhao

2015-01-01

Poor performance and network congestion are commonly observed in the streaming media single server system. This paper proposes a scheme to construct a streaming media server cluster system based on FFMpeg. In this scheme, different users are distributed to different servers according to their locations and the balance among servers is maintained by the dynamic load-balancing algorithm based on active feedback. Furthermore, a service redirection algorithm is proposed to improve the transmission efficiency of streaming media data. The experiment results show that the server cluster system has significantly alleviated the network congestion and improved the performance in comparison with the single server system. PMID:25734187

Autonomous Congestion Control in Delay-Tolerant Networks

NASA Technical Reports Server (NTRS)

Burleigh, Scott C.; Jennings, Esther H.

2005-01-01

Congestion control is an important feature that directly affects network performance. Network congestion may cause loss of data or long delays. Although this problem has been studied extensively in the Internet, the solutions for Internet congestion control do not apply readily to challenged network environments such as Delay Tolerant Networks (DTN) where end-to-end connectivity may not exist continuously and latency can be high. In DTN, end-to-end rate control is not feasible. This calls for congestion control mechanisms where the decisions can be made autonomously with local information only. We use an economic pricing model and propose a rule-based congestion control mechanism where each router can autonomously decide on whether to accept a bundle (data) based on local information such as available storage and the value and risk of accepting the bundle (derived from historical statistics).

Performance Analysis of TCP Enhancements in Satellite Data Networks

NASA Technical Reports Server (NTRS)

Broyles, Ren H.

1999-01-01

This research examines two proposed enhancements to the well-known Transport Control Protocol (TCP) in the presence of noisy communication links. The Multiple Pipes protocol is an application-level adaptation of the standard TCP protocol, where several TCP links cooperate to transfer data. The Space Communication Protocol Standard - Transport Protocol (SCPS-TP) modifies TCP to optimize performance in a satellite environment. While SCPS-TP has inherent advantages that allow it to deliver data more rapidly than Multiple Pipes, the protocol, when optimized for operation in a high-error environment, is not compatible with legacy TCP systems, and requires changes to the TCP specification. This investigation determines the level of improvement offered by SCPS-TP's Corruption Mode, which will help determine if migration to the protocol is appropriate in different environments. As the percentage of corrupted packets approaches 5 %, Multiple Pipes can take over five times longer than SCPS-TP to deliver data. At high error rates, SCPS-TP's advantage is primarily caused by Multiple Pipes' use of congestion control algorithms. The lack of congestion control, however, limits the systems in which SCPS-TP can be effectively used.

Delivering Faster Congestion Feedback with the Mark-Front Strategy

NASA Technical Reports Server (NTRS)

Liu, Chunlei; Jain, Raj

2001-01-01

Computer networks use congestion feedback from the routers and destinations to control the transmission load. Delivering timely congestion feedback is essential to the performance of networks. Reaction to the congestion can be more effective if faster feedback is provided. Current TCP/IP networks use timeout, duplicate Acknowledgement Packets (ACKs) and explicit congestion notification (ECN) to deliver the congestion feedback, each provides a faster feedback than the previous method. In this paper, we propose a markfront strategy that delivers an even faster congestion feedback. With analytical and simulation results, we show that mark-front strategy reduces buffer size requirement, improves link efficiency and provides better fairness among users. Keywords: Explicit Congestion Notification, mark-front, congestion control, buffer size requirement, fairness.

An Airway Network Flow Assignment Approach Based on an Efficient Multiobjective Optimization Framework

PubMed Central

Zhang, Xuejun; Lei, Jiaxing

2015-01-01

Considering reducing the airspace congestion and the flight delay simultaneously, this paper formulates the airway network flow assignment (ANFA) problem as a multiobjective optimization model and presents a new multiobjective optimization framework to solve it. Firstly, an effective multi-island parallel evolution algorithm with multiple evolution populations is employed to improve the optimization capability. Secondly, the nondominated sorting genetic algorithm II is applied for each population. In addition, a cooperative coevolution algorithm is adapted to divide the ANFA problem into several low-dimensional biobjective optimization problems which are easier to deal with. Finally, in order to maintain the diversity of solutions and to avoid prematurity, a dynamic adjustment operator based on solution congestion degree is specifically designed for the ANFA problem. Simulation results using the real traffic data from China air route network and daily flight plans demonstrate that the proposed approach can improve the solution quality effectively, showing superiority to the existing approaches such as the multiobjective genetic algorithm, the well-known multiobjective evolutionary algorithm based on decomposition, and a cooperative coevolution multiobjective algorithm as well as other parallel evolution algorithms with different migration topology. PMID:26180840

Network-optimized congestion pricing : a parable, model and algorithm

DOT National Transportation Integrated Search

1995-05-31

This paper recites a parable, formulates a model and devises an algorithm for optimizing tolls on a road network. Such tolls induce an equilibrium traffic flow that is at once system-optimal and user-optimal. The parable introduces the network-wide c...

Congestion and flow control in signaling system no. 7: Impacts of intelligent networks and new services

NASA Astrophysics Data System (ADS)

Zepf, Joachim; Rufa, Gerhard

1994-04-01

This paper focuses on the transient performance analysis of the congestion and flow control mechanisms in CCITT Signaling System No. 7 (SS7). Special attention is directed to the impacts of the introduction of intelligent services and new applications, e.g., Freephone, credit card services, user-to-user signaling, etc. In particular, we show that signaling traffic characteristics like signaling scenarios or signaling message length as well as end-to-end signaling capabilities have a significant influence on the congestion and flow control and, therefore, on the real-time signaling performance. One important result of our performance studies is that if, e.g., intelligent services are introduced, the SS7 congestion and flow control does not work correctly. To solve this problem, some reinvestigations into these mechanisms would be necessary. Therefore, some approaches, e.g., modification of the Signaling Connection Control Part (SCCP) congestion control, usage of the SCCP relay function, or a redesign of the MTP flow control procedures are discussed in order to guarantee the efficacy of the congestion and flow control mechanisms also in the future.

High-Throughput, Survivable Protocols for CDMA Packet-Radio Networks (SRNTN-74)

DTIC Science & Technology

1990-03-01

published in a paper by Jubin and Tornow [2], however the reader must be aware that the current SURAP algorithms deviate slightly from this reference...threading policy outlined by Jubin and Tornow is equivalent to a link- level window size of one, meaning a policy of not transmitting a new packet to a... Tornow . The DARPA packet-radio network protocols. Proceedings of the IEEE, 75(1):21-32, January 1987. [31 N. Gower and J. Jubin. Congestion control using

Congestion and flow control in signaling system No. 7: Impacts of intelligent networks and new services

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

Zepf, J.; Rufa, G.

1994-04-01

This paper focuses on the transient performance analysis of the congestion and flow control mechanisms in CCITT Signaling System No. 7 (SS7). Special attention is directed to the impacts of the introduction of intelligent services and new applications, e.g., Freephone, credit card services, user-to-user signaling, etc. In particular, we show that signaling traffic characteristics like signaling scenarios or signaling message length as well as end-to-end signaling capabilities have a significant influence on the congestion and flow control and, therefore, on the real-time signaling performance. One important result of our performance studies is that if, e.g., intelligent services are introduced, themore » SS7 congestion and flow control does not work correctly. To solve this problem, some reinvestigations into these mechanisms would be necessary. Therefore, some approaches, e.g., modification of the Signaling Connection Control Part (SCCP) congestion control, usage of the SCCP relay function, or a redesign of the MTP flow control procedures are discussed in order to guarantee the efficacy of the congestion and flow control mechanisms also in the future. 16 refs.« less

Congestion patterns of electric vehicles with limited battery capacity.

PubMed

Jing, Wentao; Ramezani, Mohsen; An, Kun; Kim, Inhi

2018-01-01

The path choice behavior of battery electric vehicle (BEV) drivers is influenced by the lack of public charging stations, limited battery capacity, range anxiety and long battery charging time. This paper investigates the congestion/flow pattern captured by stochastic user equilibrium (SUE) traffic assignment problem in transportation networks with BEVs, where the BEV paths are restricted by their battery capacities. The BEV energy consumption is assumed to be a linear function of path length and path travel time, which addresses both path distance limit problem and road congestion effect. A mathematical programming model is proposed for the path-based SUE traffic assignment where the path cost is the sum of the corresponding link costs and a path specific out-of-energy penalty. We then apply the convergent Lagrangian dual method to transform the original problem into a concave maximization problem and develop a customized gradient projection algorithm to solve it. A column generation procedure is incorporated to generate the path set. Finally, two numerical examples are presented to demonstrate the applicability of the proposed model and the solution algorithm.

Congestion patterns of electric vehicles with limited battery capacity

PubMed Central

2018-01-01

The path choice behavior of battery electric vehicle (BEV) drivers is influenced by the lack of public charging stations, limited battery capacity, range anxiety and long battery charging time. This paper investigates the congestion/flow pattern captured by stochastic user equilibrium (SUE) traffic assignment problem in transportation networks with BEVs, where the BEV paths are restricted by their battery capacities. The BEV energy consumption is assumed to be a linear function of path length and path travel time, which addresses both path distance limit problem and road congestion effect. A mathematical programming model is proposed for the path-based SUE traffic assignment where the path cost is the sum of the corresponding link costs and a path specific out-of-energy penalty. We then apply the convergent Lagrangian dual method to transform the original problem into a concave maximization problem and develop a customized gradient projection algorithm to solve it. A column generation procedure is incorporated to generate the path set. Finally, two numerical examples are presented to demonstrate the applicability of the proposed model and the solution algorithm. PMID:29543875

UAS Conflict-Avoidance Using Multiagent RL with Abstract Strategy Type Communication

NASA Technical Reports Server (NTRS)

Rebhuhn, Carrie; Knudson, Matt; Tumer, Kagan

2014-01-01

The use of unmanned aerial systems (UAS) in the national airspace is of growing interest to the research community. Safety and scalability of control algorithms are key to the successful integration of autonomous system into a human-populated airspace. In order to ensure safety while still maintaining efficient paths of travel, these algorithms must also accommodate heterogeneity of path strategies of its neighbors. We show that, using multiagent RL, we can improve the speed with which conflicts are resolved in cases with up to 80 aircraft within a section of the airspace. In addition, we show that the introduction of abstract agent strategy types to partition the state space is helpful in resolving conflicts, particularly in high congestion.

Announced Strategy Types in Multiagent RL for Conflict-Avoidance in the National Airspace

NASA Technical Reports Server (NTRS)

Rebhuhn, Carrie; Knudson, Matthew D.; Tumer, Kagan

2014-01-01

The use of unmanned aerial systems (UAS) in the national airspace is of growing interest to the research community. Safety and scalability of control algorithms are key to the successful integration of autonomous system into a human-populated airspace. In order to ensure safety while still maintaining efficient paths of travel, these algorithms must also accommodate heterogeneity of path strategies of its neighbors. We show that, using multiagent RL, we can improve the speed with which conflicts are resolved in cases with up to 80 aircraft within a section of the airspace. In addition, we show that the introduction of abstract agent strategy types to partition the state space is helpful in resolving conflicts, particularly in high congestion.

On-board congestion control for satellite packet switching networks

NASA Technical Reports Server (NTRS)

Chu, Pong P.

1991-01-01

It is desirable to incorporate packet switching capability on-board for future communication satellites. Because of the statistical nature of packet communication, incoming traffic fluctuates and may cause congestion. Thus, it is necessary to incorporate a congestion control mechanism as part of the on-board processing to smooth and regulate the bursty traffic. Although there are extensive studies on congestion control for both baseband and broadband terrestrial networks, these schemes are not feasible for space based switching networks because of the unique characteristics of satellite link. Here, we propose a new congestion control method for on-board satellite packet switching. This scheme takes into consideration the long propagation delay in satellite link and takes advantage of the the satellite's broadcasting capability. It divides the control between the ground terminals and satellite, but distributes the primary responsibility to ground terminals and only requires minimal hardware resource on-board satellite.

Economic analysis for transmission operation and planning

NASA Astrophysics Data System (ADS)

Zhou, Qun

2011-12-01

Restructuring of the electric power industry has caused dramatic changes in the use of transmission system. The increasing congestion conditions as well as the necessity of integrating renewable energy introduce new challenges and uncertainties to transmission operation and planning. Accurate short-term congestion forecasting facilitates market traders in bidding and trading activities. Cost sharing and recovery issue is a major impediment for long-term transmission investment to integrate renewable energy. In this research, a new short-term forecasting algorithm is proposed for predicting congestion, LMPs, and other power system variables based on the concept of system patterns. The advantage of this algorithm relative to standard statistical forecasting methods is that structural aspects underlying power market operations are exploited to reduce the forecasting error. The advantage relative to previously proposed structural forecasting methods is that data requirements are substantially reduced. Forecasting results based on a NYISO case study demonstrate the feasibility and accuracy of the proposed algorithm. Moreover, a negotiation methodology is developed to guide transmission investment for integrating renewable energy. Built on Nash Bargaining theory, the negotiation of investment plans and payment rate can proceed between renewable generation and transmission companies for cost sharing and recovery. The proposed approach is applied to Garver's six bus system. The numerical results demonstrate fairness and efficiency of the approach, and hence can be used as guidelines for renewable energy investors. The results also shed light on policy-making of renewable energy subsidies.

Performance analysis of SS7 congestion controls under sustained overload

NASA Astrophysics Data System (ADS)

Manfield, David R.; Millsteed, Gregory K.; Zukerman, Moshe

1994-04-01

Congestion controls are a key factor in achieving the robust performance required of common channel signaling (CCS) networks in the face of partial network failures and extreme traffic loads, especially as networks become large and carry high traffic volume. The CCITT recommendations define a number of types of congestion control, and the parameters of the controls must be well set in order to ensure their efficacy under transient and sustained signalling network overload. The objective of this paper is to present a modeling approach to the determination of the network parameters that govern the performance of the SS7 congestion controls under sustained overload. Results of the investigation by simulation are presented and discussed.

Approach for counting vehicles in congested traffic flow

NASA Astrophysics Data System (ADS)

Tan, Xiaojun; Li, Jun; Liu, Wei

2005-02-01

More and more image sensors are used in intelligent transportation systems. In practice, occlusion is always a problem when counting vehicles in congested traffic. This paper tries to present an approach to solve the problem. The proposed approach consists of three main procedures. Firstly, a new algorithm of background subtraction is performed. The aim is to segment moving objects from an illumination-variant background. Secondly, object tracking is performed, where the CONDENSATION algorithm is used. This can avoid the problem of matching vehicles in successive frames. Thirdly, an inspecting procedure is executed to count the vehicles. When a bus firstly occludes a car and then the bus moves away a few frames later, the car will appear in the scene. The inspecting procedure should find the "new" car and add it as a tracking object.

Design and Implementation of Real-Time Vehicular Camera for Driver Assistance and Traffic Congestion Estimation

PubMed Central

Son, Sanghyun; Baek, Yunju

2015-01-01

As society has developed, the number of vehicles has increased and road conditions have become complicated, increasing the risk of crashes. Therefore, a service that provides safe vehicle control and various types of information to the driver is urgently needed. In this study, we designed and implemented a real-time traffic information system and a smart camera device for smart driver assistance systems. We selected a commercial device for the smart driver assistance systems, and applied a computer vision algorithm to perform image recognition. For application to the dynamic region of interest, dynamic frame skip methods were implemented to perform parallel processing in order to enable real-time operation. In addition, we designed and implemented a model to estimate congestion by analyzing traffic information. The performance of the proposed method was evaluated using images of a real road environment. We found that the processing time improved by 15.4 times when all the proposed methods were applied in the application. Further, we found experimentally that there was little or no change in the recognition accuracy when the proposed method was applied. Using the traffic congestion estimation model, we also found that the average error rate of the proposed model was 5.3%. PMID:26295230

Design and Implementation of Real-Time Vehicular Camera for Driver Assistance and Traffic Congestion Estimation.

PubMed

Son, Sanghyun; Baek, Yunju

2015-08-18

As society has developed, the number of vehicles has increased and road conditions have become complicated, increasing the risk of crashes. Therefore, a service that provides safe vehicle control and various types of information to the driver is urgently needed. In this study, we designed and implemented a real-time traffic information system and a smart camera device for smart driver assistance systems. We selected a commercial device for the smart driver assistance systems, and applied a computer vision algorithm to perform image recognition. For application to the dynamic region of interest, dynamic frame skip methods were implemented to perform parallel processing in order to enable real-time operation. In addition, we designed and implemented a model to estimate congestion by analyzing traffic information. The performance of the proposed method was evaluated using images of a real road environment. We found that the processing time improved by 15.4 times when all the proposed methods were applied in the application. Further, we found experimentally that there was little or no change in the recognition accuracy when the proposed method was applied. Using the traffic congestion estimation model, we also found that the average error rate of the proposed model was 5.3%.

Fixture congestion modulates post-match recovery kinetics in professional soccer players.

PubMed

Lundberg, Tommy R; Weckström, Kristoffer

2017-01-01

This study examined the influence of fixture congestion on physical performance and biochemical variables in professional male footballers. After 3 competitive matches within a week (3M cycle), 16 players underwent blood sampling and field testing 72 h after the last match. The same tests were performed after a regular 1 match-week cycle (1M cycle). The 1M vs. 3M change scores were compared between Congested (high match exposure) and non-selected Control players. The change score in muscle soreness was greater (effect size 1.0; CI 0.0-1.9) in the Congested players than Controls, indicating a possible negative effect of fixture congestion. There were no effects on sprint and jump performance. The change in plasma (P)-Urea was greater in Congested players than controls (effect size 1.3; CI 0.3-2.2). The effects on other blood variables were either non-existing/trivial, or unclear. Altogether, physical fitness and immune function were not compromised by match congestion, yet some indices of physiological stress and muscle damage were still evident.

A new memetic algorithm for mitigating tandem automated guided vehicle system partitioning problem

NASA Astrophysics Data System (ADS)

Pourrahimian, Parinaz

2017-11-01

Automated Guided Vehicle System (AGVS) provides the flexibility and automation demanded by Flexible Manufacturing System (FMS). However, with the growing concern on responsible management of resource use, it is crucial to manage these vehicles in an efficient way in order reduces travel time and controls conflicts and congestions. This paper presents the development process of a new Memetic Algorithm (MA) for optimizing partitioning problem of tandem AGVS. MAs employ a Genetic Algorithm (GA), as a global search, and apply a local search to bring the solutions to a local optimum point. A new Tabu Search (TS) has been developed and combined with a GA to refine the newly generated individuals by GA. The aim of the proposed algorithm is to minimize the maximum workload of the system. After all, the performance of the proposed algorithm is evaluated using Matlab. This study also compared the objective function of the proposed MA with GA. The results showed that the TS, as a local search, significantly improves the objective function of the GA for different system sizes with large and small numbers of zone by 1.26 in average.

Reducing a congestion with introduce the greedy algorithm on traffic light control

NASA Astrophysics Data System (ADS)

Catur Siswipraptini, Puji; Hendro Martono, Wisnu; Hartanti, Dian

2018-03-01

The density of vehicles causes congestion seen at every junction in the city of jakarta due to the static or manual traffic timing lamp system consequently the length of the queue at the junction is uncertain. The research has been aimed at designing a sensor based traffic system based on the queue length detection of the vehicle to optimize the duration of the green light. In detecting the length of the queue of vehicles using infrared sensor assistance placed in each intersection path, then apply Greedy algorithm to help accelerate the movement of green light duration for the path that requires, while to apply the traffic lights regulation program based on greedy algorithm which is then stored on microcontroller with Arduino Mega 2560 type. Where a developed system implements the greedy algorithm with the help of the infrared sensor it will extend the duration of the green light on the long vehicle queue and accelerate the duration of the green light at the intersection that has the queue not too dense. Furthermore, the design is made to form an artificial form of the actual situation of the scale model or simple simulator (next we just called as scale model of simulator) of the intersection then tested. Sensors used are infrared sensors, where the placement of sensors in each intersection on the scale model is placed within 10 cm of each sensor and serves as a queue detector. From the results of the test process on the scale model with a longer queue obtained longer green light time so it will fix the problem of long queue of vehicles. Using greedy algorithms can add long green lights for 2 seconds on tracks that have long queues at least three sensor levels and accelerate time at other intersections that have longer queue sensor levels less than level three.

Traffic Congestion Detection System through Connected Vehicles and Big Data

PubMed Central

Cárdenas-Benítez, Néstor; Aquino-Santos, Raúl; Magaña-Espinoza, Pedro; Aguilar-Velazco, José; Edwards-Block, Arthur; Medina Cass, Aldo

2016-01-01

This article discusses the simulation and evaluation of a traffic congestion detection system which combines inter-vehicular communications, fixed roadside infrastructure and infrastructure-to-infrastructure connectivity and big data. The system discussed in this article permits drivers to identify traffic congestion and change their routes accordingly, thus reducing the total emissions of CO2 and decreasing travel time. This system monitors, processes and stores large amounts of data, which can detect traffic congestion in a precise way by means of a series of algorithms that reduces localized vehicular emission by rerouting vehicles. To simulate and evaluate the proposed system, a big data cluster was developed based on Cassandra, which was used in tandem with the OMNeT++ discreet event network simulator, coupled with the SUMO (Simulation of Urban MObility) traffic simulator and the Veins vehicular network framework. The results validate the efficiency of the traffic detection system and its positive impact in detecting, reporting and rerouting traffic when traffic events occur. PMID:27136548

Traffic Congestion Detection System through Connected Vehicles and Big Data.

PubMed

Cárdenas-Benítez, Néstor; Aquino-Santos, Raúl; Magaña-Espinoza, Pedro; Aguilar-Velazco, José; Edwards-Block, Arthur; Medina Cass, Aldo

2016-04-28

This article discusses the simulation and evaluation of a traffic congestion detection system which combines inter-vehicular communications, fixed roadside infrastructure and infrastructure-to-infrastructure connectivity and big data. The system discussed in this article permits drivers to identify traffic congestion and change their routes accordingly, thus reducing the total emissions of CO₂ and decreasing travel time. This system monitors, processes and stores large amounts of data, which can detect traffic congestion in a precise way by means of a series of algorithms that reduces localized vehicular emission by rerouting vehicles. To simulate and evaluate the proposed system, a big data cluster was developed based on Cassandra, which was used in tandem with the OMNeT++ discreet event network simulator, coupled with the SUMO (Simulation of Urban MObility) traffic simulator and the Veins vehicular network framework. The results validate the efficiency of the traffic detection system and its positive impact in detecting, reporting and rerouting traffic when traffic events occur.

NLP based congestive heart failure case finding: A prospective analysis on statewide electronic medical records.

PubMed

Wang, Yue; Luo, Jin; Hao, Shiying; Xu, Haihua; Shin, Andrew Young; Jin, Bo; Liu, Rui; Deng, Xiaohong; Wang, Lijuan; Zheng, Le; Zhao, Yifan; Zhu, Chunqing; Hu, Zhongkai; Fu, Changlin; Hao, Yanpeng; Zhao, Yingzhen; Jiang, Yunliang; Dai, Dorothy; Culver, Devore S; Alfreds, Shaun T; Todd, Rogow; Stearns, Frank; Sylvester, Karl G; Widen, Eric; Ling, Xuefeng B

2015-12-01

In order to proactively manage congestive heart failure (CHF) patients, an effective CHF case finding algorithm is required to process both structured and unstructured electronic medical records (EMR) to allow complementary and cost-efficient identification of CHF patients. We set to identify CHF cases from both EMR codified and natural language processing (NLP) found cases. Using narrative clinical notes from all Maine Health Information Exchange (HIE) patients, the NLP case finding algorithm was retrospectively (July 1, 2012-June 30, 2013) developed with a random subset of HIE associated facilities, and blind-tested with the remaining facilities. The NLP based method was integrated into a live HIE population exploration system and validated prospectively (July 1, 2013-June 30, 2014). Total of 18,295 codified CHF patients were included in Maine HIE. Among the 253,803 subjects without CHF codings, our case finding algorithm prospectively identified 2411 uncodified CHF cases. The positive predictive value (PPV) is 0.914, and 70.1% of these 2411 cases were found to be with CHF histories in the clinical notes. A CHF case finding algorithm was developed, tested and prospectively validated. The successful integration of the CHF case findings algorithm into the Maine HIE live system is expected to improve the Maine CHF care. Copyright © 2015. Published by Elsevier Ireland Ltd.

Dynamic origin-to-destination routing of wirelessly connected, autonomous vehicles on a congested network

NASA Astrophysics Data System (ADS)

Davis, L. C.

2017-07-01

Up-to-date information wirelessly communicated among vehicles can be used to select the optimal route between a given origin and destination. To elucidate how to make use of such information, simulations are performed for autonomous vehicles traveling on a square lattice of roads. All the possible routes between the origin and the destination (without backtracking) are of the same length. Congestion is the only determinant of delay. At each intersection, right-of-way is given to the closest vehicle. There are no traffic lights. Trip times of a subject vehicle are recorded for various initial conditions using different routing algorithms. Surprisingly, the simplest algorithm, which is based on the total number of vehicles on a route, is as good as one based on computing travel times from the average velocity of vehicles on each road segment.

Efficient algorithm for locating and sizing series compensation devices in large power transmission grids: II. Solutions and applications

DOE PAGES

Frolov, Vladimir; Backhaus, Scott; Chertkov, Misha

2014-10-01

In a companion manuscript, we developed a novel optimization method for placement, sizing, and operation of Flexible Alternating Current Transmission System (FACTS) devices to relieve transmission network congestion. Specifically, we addressed FACTS that provide Series Compensation (SC) via modification of line inductance. In this manuscript, this heuristic algorithm and its solutions are explored on a number of test cases: a 30-bus test network and a realistically-sized model of the Polish grid (~ 2700 nodes and ~ 3300 lines). The results on the 30-bus network are used to study the general properties of the solutions including non-locality and sparsity. The Polishmore » grid is used as a demonstration of the computational efficiency of the heuristics that leverages sequential linearization of power flow constraints and cutting plane methods that take advantage of the sparse nature of the SC placement solutions. Using these approaches, the algorithm is able to solve an instance of Polish grid in tens of seconds. We explore the utility of the algorithm by analyzing transmission networks congested by (a) uniform load growth, (b) multiple overloaded configurations, and (c) sequential generator retirements.« less

Efficient Algorithm for Locating and Sizing Series Compensation Devices in Large Transmission Grids: Solutions and Applications (PART II)

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

Frolov, Vladimir; Backhaus, Scott N.; Chertkov, Michael

2014-01-14

In a companion manuscript, we developed a novel optimization method for placement, sizing, and operation of Flexible Alternating Current Transmission System (FACTS) devices to relieve transmission network congestion. Specifically, we addressed FACTS that provide Series Compensation (SC) via modification of line inductance. In this manuscript, this heuristic algorithm and its solutions are explored on a number of test cases: a 30-bus test network and a realistically-sized model of the Polish grid (~2700 nodes and ~3300 lines). The results on the 30-bus network are used to study the general properties of the solutions including non-locality and sparsity. The Polish grid ismore » used as a demonstration of the computational efficiency of the heuristics that leverages sequential linearization of power flow constraints and cutting plane methods that take advantage of the sparse nature of the SC placement solutions. Using these approaches, the algorithm is able to solve an instance of Polish grid in tens of seconds. We explore the utility of the algorithm by analyzing transmission networks congested by (a) uniform load growth, (b) multiple overloaded configurations, and (c) sequential generator retirements« less

Probabilistic computer model of optimal runway turnoffs

NASA Technical Reports Server (NTRS)

Schoen, M. L.; Preston, O. W.; Summers, L. G.; Nelson, B. A.; Vanderlinden, L.; Mcreynolds, M. C.

1985-01-01

Landing delays are currently a problem at major air carrier airports and many forecasters agree that airport congestion will get worse by the end of the century. It is anticipated that some types of delays can be reduced by an efficient optimal runway exist system allowing increased approach volumes necessary at congested airports. A computerized Probabilistic Runway Turnoff Model which locates exits and defines path geometry for a selected maximum occupancy time appropriate for each TERPS aircraft category is defined. The model includes an algorithm for lateral ride comfort limits.

[Use of antihypertensive drug therapy and risk of development of congestive heart failure].

PubMed

Sobrino, Javier; Plana, Jaume; Felip, Angela; Doménech, Mónica; Reth, Peter; Adrián, María Jesús; de la Sierra, Alejandro

2004-09-18

It has been suggested that the use of some antihypertensive agents may favour the development of congestive heart failure. The aim of the present study was to evaluate such a possible association in patients who had a new diagnosis of congestive heart failure. This was a retrospective case-control study of 81 patients who had a first hospital admission with a new diagnosis of congestive heart failure (cases) and 162 patients admitted for other hypertensive complications (controls). Previous antihypertensive drug use was registered and the possible association with congestive heart failure was evaluated. The presence of congestive heart failure was not associated with the use of any antihypertensive drug class. When treatments were grouped in classic (diuretics and betablockers) or modern (calcium channel blockers, angiotensin-converting-enzyme inhibitors, alphablockers or angiotensin receptor blockers), a negative association was observed with the latter group, which was observed in 48.1% of cases and 63.6% of controls (odds ratio: 0.532; 95% confidence interval, 0.310-0.913). This association was lost after adjustment for other cardiovascular risk factors or previous hypertensive complications. The development of congestive heart failure was not associated with the use of any specific antihypertensive drug class. From the present evidence, it is not possible to recommend a specific antihypertensive agent in patients at risk of developing congestive heart failure but without evidence of such disease.

In Vivo Evaluation of Active and Passive Physiological Control Systems for Rotary Left and Right Ventricular Assist Devices.

PubMed

Gregory, Shaun D; Stevens, Michael C; Pauls, Jo P; Schummy, Emma; Diab, Sara; Thomson, Bruce; Anderson, Ben; Tansley, Geoff; Salamonsen, Robert; Fraser, John F; Timms, Daniel

2016-09-01

Preventing ventricular suction and venous congestion through balancing flow rates and circulatory volumes with dual rotary ventricular assist devices (VADs) configured for biventricular support is clinically challenging due to their low preload and high afterload sensitivities relative to the natural heart. This study presents the in vivo evaluation of several physiological control systems, which aim to prevent ventricular suction and venous congestion. The control systems included a sensor-based, master/slave (MS) controller that altered left and right VAD speed based on pressure and flow; a sensor-less compliant inflow cannula (IC), which altered inlet resistance and, therefore, pump flow based on preload; a sensor-less compliant outflow cannula (OC) on the right VAD, which altered outlet resistance and thus pump flow based on afterload; and a combined controller, which incorporated the MS controller, compliant IC, and compliant OC. Each control system was evaluated in vivo under step increases in systemic (SVR ∼1400-2400 dyne/s/cm(5) ) and pulmonary (PVR ∼200-1000 dyne/s/cm(5) ) vascular resistances in four sheep supported by dual rotary VADs in a biventricular assist configuration. Constant speed support was also evaluated for comparison and resulted in suction events during all resistance increases and pulmonary congestion during SVR increases. The MS controller reduced suction events and prevented congestion through an initial sharp reduction in pump flow followed by a gradual return to baseline (5.0 L/min). The compliant IC prevented suction events; however, reduced pump flows and pulmonary congestion were noted during the SVR increase. The compliant OC maintained pump flow close to baseline (5.0 L/min) and prevented suction and congestion during PVR increases. The combined controller responded similarly to the MS controller to prevent suction and congestion events in all cases while providing a backup system in the event of single controller failure. © 2016 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

Distributive routing and congestion control in wireless multihop ad hoc communication networks

NASA Astrophysics Data System (ADS)

Glauche, Ingmar; Krause, Wolfram; Sollacher, Rudolf; Greiner, Martin

2004-10-01

Due to their inherent complexity, engineered wireless multihop ad hoc communication networks represent a technological challenge. Having no mastering infrastructure the nodes have to selforganize themselves in such a way that for example network connectivity, good data traffic performance and robustness are guaranteed. In this contribution the focus is on routing and congestion control. First, random data traffic along shortest path routes is studied by simulations as well as theoretical modeling. Measures of congestion like end-to-end time delay and relaxation times are given. A scaling law of the average time delay with respect to network size is revealed and found to depend on the underlying network topology. In the second step, a distributive routing and congestion control is proposed. Each node locally propagates its routing cost estimates and information about its congestion state to its neighbors, which then update their respective cost estimates. This allows for a flexible adaptation of end-to-end routes to the overall congestion state of the network. Compared to shortest-path routing, the critical network load is significantly increased.

A novel fair active queue management algorithm based on traffic delay jitter

NASA Astrophysics Data System (ADS)

Wang, Xue-Shun; Yu, Shao-Hua; Dai, Jin-You; Luo, Ting

2009-11-01

In order to guarantee the quantity of data traffic delivered in the network, congestion control strategy is adopted. According to the study of many active queue management (AQM) algorithms, this paper proposes a novel active queue management algorithm named JFED. JFED can stabilize queue length at a desirable level by adjusting output traffic rate and adopting a reasonable calculation of packet drop probability based on buffer queue length and traffic jitter; and it support burst packet traffic through the packet delay jitter, so that it can traffic flow medium data. JFED impose effective punishment upon non-responsible flow with a full stateless method. To verify the performance of JFED, it is implemented in NS2 and is compared with RED and CHOKe with respect to different performance metrics. Simulation results show that the proposed JFED algorithm outperforms RED and CHOKe in stabilizing instantaneous queue length and in fairness. It is also shown that JFED enables the link capacity to be fully utilized by stabilizing the queue length at a desirable level, while not incurring excessive packet loss ratio.

Scalable service architecture for providing strong service guarantees

NASA Astrophysics Data System (ADS)

Christin, Nicolas; Liebeherr, Joerg

2002-07-01

For the past decade, a lot of Internet research has been devoted to providing different levels of service to applications. Initial proposals for service differentiation provided strong service guarantees, with strict bounds on delays, loss rates, and throughput, but required high overhead in terms of computational complexity and memory, both of which raise scalability concerns. Recently, the interest has shifted to service architectures with low overhead. However, these newer service architectures only provide weak service guarantees, which do not always address the needs of applications. In this paper, we describe a service architecture that supports strong service guarantees, can be implemented with low computational complexity, and only requires to maintain little state information. A key mechanism of the proposed service architecture is that it addresses scheduling and buffer management in a single algorithm. The presented architecture offers no solution for controlling the amount of traffic that enters the network. Instead, we plan on exploiting feedback mechanisms of TCP congestion control algorithms for the purpose of regulating the traffic entering the network.

Distributed Optimization of Multi-Agent Systems: Framework, Local Optimizer, and Applications

NASA Astrophysics Data System (ADS)

Zu, Yue

Convex optimization problem can be solved in a centralized or distributed manner. Compared with centralized methods based on single-agent system, distributed algorithms rely on multi-agent systems with information exchanging among connected neighbors, which leads to great improvement on the system fault tolerance. Thus, a task within multi-agent system can be completed with presence of partial agent failures. By problem decomposition, a large-scale problem can be divided into a set of small-scale sub-problems that can be solved in sequence/parallel. Hence, the computational complexity is greatly reduced by distributed algorithm in multi-agent system. Moreover, distributed algorithm allows data collected and stored in a distributed fashion, which successfully overcomes the drawbacks of using multicast due to the bandwidth limitation. Distributed algorithm has been applied in solving a variety of real-world problems. Our research focuses on the framework and local optimizer design in practical engineering applications. In the first one, we propose a multi-sensor and multi-agent scheme for spatial motion estimation of a rigid body. Estimation performance is improved in terms of accuracy and convergence speed. Second, we develop a cyber-physical system and implement distributed computation devices to optimize the in-building evacuation path when hazard occurs. The proposed Bellman-Ford Dual-Subgradient path planning method relieves the congestion in corridor and the exit areas. At last, highway traffic flow is managed by adjusting speed limits to minimize the fuel consumption and travel time in the third project. Optimal control strategy is designed through both centralized and distributed algorithm based on convex problem formulation. Moreover, a hybrid control scheme is presented for highway network travel time minimization. Compared with no controlled case or conventional highway traffic control strategy, the proposed hybrid control strategy greatly reduces total travel time on test highway network.

Losartan corrects abnormal frequency response of renal vasculature in congestive heart failure.

PubMed

DiBona, Gerald F; Sawin, Linda L

2003-11-01

In congestive heart failure, renal blood flow is decreased and renal vascular resistance is increased in a setting of increased activity of both the sympathetic nervous and renin-angiotensin systems. The renal vasoconstrictor response to renal nerve stimulation is enhanced. This is associated with an abnormality in the low-pass filter function of the renal vasculature wherein higher frequencies (> or =0.01 Hz) within renal sympathetic nerve activity are not normally attenuated and are passed into the renal blood flow signal. This study tested the hypothesis that excess angiotensin II action mediates the abnormal frequency response characteristics of the renal vasculature in congestive heart failure. In anesthetized rats, the renal vasoconstrictor response to graded frequency renal nerve stimulation was significantly greater in congestive heart failure than in control rats. Losartan attenuated the renal vasoconstrictor response to a significantly greater degree in congestive heart failure than in control rats. In control rats, the frequency response of the renal vasculature was that of a first order (-20 dB/frequency decade) low-pass filter with a corner frequency (-3 dB, 30% attenuation) of 0.002 Hz and 97% attenuation (-30 dB) at > or =0.1 Hz. In congestive heart failure rats, attenuation did not exceed 45% (-5 dB) over the frequency range of 0.001-0.6 Hz. The frequency response of the renal vasculature was not affected by losartan treatment in control rats but was completely restored to normal by losartan treatment in congestive heart failure rats. The enhanced renal vasoconstrictor response to renal nerve stimulation and the associated abnormality in the frequency response characteristics of the renal vasculature seen in congestive heart failure are mediated by the action of angiotensin II on renal angiotensin II AT1 receptors.

Signalling and obfuscation for congestion control

NASA Astrophysics Data System (ADS)

Mareček, Jakub; Shorten, Robert; Yu, Jia Yuan

2015-10-01

We aim to reduce the social cost of congestion in many smart city applications. In our model of congestion, agents interact over limited resources after receiving signals from a central agent that observes the state of congestion in real time. Under natural models of agent populations, we develop new signalling schemes and show that by introducing a non-trivial amount of uncertainty in the signals, we reduce the social cost of congestion, i.e., improve social welfare. The signalling schemes are efficient in terms of both communication and computation, and are consistent with past observations of the congestion. Moreover, the resulting population dynamics converge under reasonable assumptions.

A self-adaptive toll rate algorithm for high occupancy toll (HOT) lane operations.

DOT National Transportation Integrated Search

2009-12-01

Dramatically increasing travel demands and insufficient traffic facility supplies have resulted in severe : traffic congestion. High Occupancy Toll (HOT) lane operations have been proposed as one of the most : applicable and cost-effective countermea...

IDMA: improving the defense against malicious attack for mobile ad hoc networks based on ARIP protocol

NASA Astrophysics Data System (ADS)

Peng, Chaorong; Chen, Chang Wen

2008-04-01

Malicious nodes are mounting increasingly sophisticated attacking operations on the Mobile Ad Hoc Networks (MANETs). This is mainly because the IP-based MANETs are vulnerable to attacks by various malicious nodes. However, the defense against malicious attack can be improved when a new layer of network architecture can be developed to separate true IP address from disclosing to the malicious nodes. In this paper, we propose a new algorithm to improve the defense against malicious attack (IDMA) that is based on a recently developed Assignment Router Identify Protocol (ARIP) for the clustering-based MANET management. In the ARIP protocol, we design the ARIP architecture based on the new Identity instead of the vulnerable IP addresses to provide the required security that is embedded seamlessly into the overall network architecture. We make full use of ARIP's special property to monitor gateway forward packets by Reply Request Route Packets (RREP) without additional intrusion detection layer. We name this new algorithm IDMA because of its inherent capability to improve the defense against malicious attacks. Through IDMA, a watching algorithm can be established so as to counterattack the malicious node in the routing path when it unusually drops up packets. We provide analysis examples for IDMA for the defense against a malicious node that disrupts the route discovery by impersonating the destination, or by responding with state of corrupted routing information, or by disseminating forged control traffic. The IDMA algorithm is able to counterattack the malicious node in the cases when the node lunch DoS attack by broadcast a large number of route requests, or make Target traffic congestion by delivering huge mount of data; or spoof the IP addresses and send forge packets with a fake ID to the same Target causing traffic congestion at that destination. We have implemented IDMA algorism using the GloMoSim simulator and have demonstrated its performance under a variety of operational conditions.

The Performance of Short-Term Heart Rate Variability in the Detection of Congestive Heart Failure

PubMed Central

Barros, Allan Kardec; Ohnishi, Noboru

2016-01-01

Congestive heart failure (CHF) is a cardiac disease associated with the decreasing capacity of the cardiac output. It has been shown that the CHF is the main cause of the cardiac death around the world. Some works proposed to discriminate CHF subjects from healthy subjects using either electrocardiogram (ECG) or heart rate variability (HRV) from long-term recordings. In this work, we propose an alternative framework to discriminate CHF from healthy subjects by using HRV short-term intervals based on 256 RR continuous samples. Our framework uses a matching pursuit algorithm based on Gabor functions. From the selected Gabor functions, we derived a set of features that are inputted into a hybrid framework which uses a genetic algorithm and k-nearest neighbour classifier to select a subset of features that has the best classification performance. The performance of the framework is analyzed using both Fantasia and CHF database from Physionet archives which are, respectively, composed of 40 healthy volunteers and 29 subjects. From a set of nonstandard 16 features, the proposed framework reaches an overall accuracy of 100% with five features. Our results suggest that the application of hybrid frameworks whose classifier algorithms are based on genetic algorithms has outperformed well-known classifier methods. PMID:27891509

A New TCP Congestion Control Supporting RTT-Fairness

NASA Astrophysics Data System (ADS)

Ogura, Kazumine; Nemoto, Yohei; Su, Zhou; Katto, Jiro

This paper focuses on RTT-fairness of multiple TCP flows over the Internet, and proposes a new TCP congestion control named “HRF (Hybrid RTT-Fair)-TCP”. Today, it is a serious problem that the flows having smaller RTT utilize more bandwidth than others when multiple flows having different RTT values compete in the same network. This means that a user with longer RTT may not be able to obtain sufficient bandwidth by the current methods. This RTT fairness issue has been discussed in many TCP papers. An example is CR (Constant Rate) algorithm, which achieves RTT-fairness by multiplying the square of RTT value in its window increment phase against TCP-Reno. However, the method halves its windows size same as TCP-Reno when a packet loss is detected. This makes worse its efficiency in certain network cases. On the other hand, recent proposed TCP versions essentially require throughput efficiency and TCP-friendliness with TCP-Reno. Therefore, we try to keep these advantages in our TCP design in addition to RTT-fairness. In this paper, we make intuitive analytical models in which we separate resource utilization processes into two cases: utilization of bottleneck link capacity and that of buffer space at the bottleneck link router. These models take into account three characteristic algorithms (Reno, Constant Rate, Constant Increase) in window increment phase where a sender receives an acknowledgement successfully. Their validity is proved by both simulations and implementations. From these analyses, we propose HRF-TCP which switches two modes according to observed RTT values and achieves RTT fairness. Experiments are carried out to validate the proposed method. Finally, HRF-TCP outperforms conventional methods in RTT-fairness, efficiency and friendliness with TCP-Reno.

Development of simulation techniques suitable for the analysis of air traffic control situations and instrumentation

NASA Technical Reports Server (NTRS)

1972-01-01

A terminal area simulation is described which permits analysis and synthesis of current and advanced air traffic management system configurations including ground and airborne instrumentation and new and modified aircraft characteristics. Ground elements in the simulation include navigation aids, surveillance radars, communication links, air-route structuring, ATC procedures, airport geometries and runway handling constraints. Airborne elements include traffic samples with individual aircraft performance and operating characteristics and aircraft navigation equipment. The simulation also contains algorithms for conflict detection, conflict resolution, sequencing and pilot-controller data links. The simulation model is used to determine the sensitivities of terminal area traffic flow, safety and congestion to aircraft performance characteristics, avionics systems, and other ATC elements.

Effects of inter-packet spacing on the delivery of multimedia content

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

Kapadia, A. C.; Feng, A. C.; Feng, W. C.

2001-01-01

Streaming multimedia content with UDP has become increasingly popular over distributed systems such as the Internet. However, because UDP does not possess any congestion-control mechanism and most best-effort trafic is served by the congestion-controlled TCP, UDP flows steal bandwidth from TCP to the point that TCP flows can starve for network resources. Furthermore, such applications may cause the Internet infrastructure to eventually suffer from congestion collapse because UDP trafic does not self-regulate itself. To address this problem, next-generation Internet routers will implement active queue-management schemes to punish malicious traffic, e.g., non-adaptive UDP flows, and to the improve the performance ofmore » congestion-controlled traffic, e.g., TCP flows. The arrival of such routers will cripple the performance of today's UDP-based multimedia applications. So, in this paper, we introduce the notion of inter-packet spacing with control feedback to enable these UDP-based applications to perform well in the next-generation Internet while being adaptive and self-regulating. When compared with traditional UDP-based multimedia streaming, we illustrate that our counterintuitive, interpacket-spacing scheme with control feedback can reduce packet loss by 90% without adversely affecting delivered throughput. Keywords: network protocol, multimedia, packet spacing, rate-adjusting congestion control.« less

Traffic control strategies for congested freeways and work zones.

DOT National Transportation Integrated Search

2008-10-01

The primary objective of the research was to identify and evaluate effective ways of improving traffic operations and : safety on congested freeways. There was particular interest in finding condition-responsive traffic control solutions : for the fo...

Analysis of travel-time reliability for freight corridors connecting the Pacific Northwest.

DOT National Transportation Integrated Search

2012-11-01

A new methodology and algorithms were developed to combine diverse data sources and to estimate the impacts of recurrent and non-recurrent : congestion on freight movements reliability and delays, costs, and emissions. The results suggest that tra...

Ant colony optimization algorithm for signal coordination of oversaturated traffic networks.

DOT National Transportation Integrated Search

2010-05-01

Traffic congestion is a daily and growing problem of the modern era in mostly all major cities in the world. : Increasing traffic demand strains the existing transportation system, leading to oversaturated network : conditions, especially at peak hou...

Applications of variable speed control for contending with recurrent highway congestion.

DOT National Transportation Integrated Search

2014-07-01

This research project developed vital operational guidelines for design of a variable speed limit (VSL) system and its integrated operations with ramp metering control in contending with recurrent highway congestion. The developed guidelines can serv...

Mean Field Type Control with Congestion

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

Achdou, Yves, E-mail: achdou@ljll.univ-paris-diderot.fr; Laurière, Mathieu

2016-06-15

We analyze some systems of partial differential equations arising in the theory of mean field type control with congestion effects. We look for weak solutions. Our main result is the existence and uniqueness of suitably defined weak solutions, which are characterized as the optima of two optimal control problems in duality.

A resilience-oriented approach for quantitatively assessing recurrent spatial-temporal congestion on urban roads.

PubMed

Tang, Junqing; Heinimann, Hans Rudolf

2018-01-01

Traffic congestion brings not only delay and inconvenience, but other associated national concerns, such as greenhouse gases, air pollutants, road safety issues and risks. Identification, measurement, tracking, and control of urban recurrent congestion are vital for building a livable and smart community. A considerable amount of works has made contributions to tackle the problem. Several methods, such as time-based approaches and level of service, can be effective for characterizing congestion on urban streets. However, studies with systemic perspectives have been minor in congestion quantification. Resilience, on the other hand, is an emerging concept that focuses on comprehensive systemic performance and characterizes the ability of a system to cope with disturbance and to recover its functionality. In this paper, we symbolized recurrent congestion as internal disturbance and proposed a modified metric inspired by the well-applied "R4" resilience-triangle framework. We constructed the metric with generic dimensions from both resilience engineering and transport science to quantify recurrent congestion based on spatial-temporal traffic patterns and made the comparison with other two approaches in freeway and signal-controlled arterial cases. Results showed that the metric can effectively capture congestion patterns in the study area and provides a quantitative benchmark for comparison. Also, it suggested not only a good comparative performance in measuring strength of proposed metric, but also its capability of considering the discharging process in congestion. The sensitivity tests showed that proposed metric possesses robustness against parameter perturbation in Robustness Range (RR), but the number of identified congestion patterns can be influenced by the existence of ϵ. In addition, the Elasticity Threshold (ET) and the spatial dimension of cell-based platform differ the congestion results significantly on both the detected number and intensity. By tackling this conventional problem with emerging concept, our metric provides a systemic alternative approach and enriches the toolbox for congestion assessment. Future work will be conducted on a larger scale with multiplex scenarios in various traffic conditions.

Extended shortest path selection for package routing of complex networks

NASA Astrophysics Data System (ADS)

Ye, Fan; Zhang, Lei; Wang, Bing-Hong; Liu, Lu; Zhang, Xing-Yi

The routing strategy plays a very important role in complex networks such as Internet system and Peer-to-Peer networks. However, most of the previous work concentrates only on the path selection, e.g. Flooding and Random Walk, or finding the shortest path (SP) and rarely considering the local load information such as SP and Distance Vector Routing. Flow-based Routing mainly considers load balance and still cannot achieve best optimization. Thus, in this paper, we propose a novel dynamic routing strategy on complex network by incorporating the local load information into SP algorithm to enhance the traffic flow routing optimization. It was found that the flow in a network is greatly affected by the waiting time of the network, so we should not consider only choosing optimized path for package transformation but also consider node congestion. As a result, the packages should be transmitted with a global optimized path with smaller congestion and relatively short distance. Analysis work and simulation experiments show that the proposed algorithm can largely enhance the network flow with the maximum throughput within an acceptable calculating time. The detailed analysis of the algorithm will also be provided for explaining the efficiency.

Effect of venous and lymphatic congestion on lymph capillary pressure of the skin in healthy volunteers and patients with lymph edema.

PubMed

Gretener, S B; Läuchli, S; Leu, A J; Koppensteiner, R; Franzeck, U K

2000-01-01

The aim of the present study was to assess the influence of venous and lymphatic congestion on lymph capillary pressure (LCP) in the skin of the foot dorsum of healthy volunteers and of patients with lymph edema. LCP was measured at the foot dorsum of 12 patients with lymph edema and 18 healthy volunteers using the servo-nulling technique. Glass micropipettes (7-9 microm) were inserted under microscopic control into lymphatic microvessels visualized by fluorescence microlymphography before and during venous congestion. Venous and lymphatic congestion was attained by cuff compression (50 mm Hg) at the thigh level. Simultaneously, the capillary filtration rate was measured using strain gauge plethysmography. The mean LCP in patients with lymph edema increased significantly (p < 0.05) during congestion (15.7 +/- 8.8 mm Hg) compared to the control value (12.2 +/- 8.9 mm Hg). The corresponding values of LCP in healthy volunteers were 4.3 +/- 2.6 mm Hg during congestion and 2.6 +/- 2.8 mm Hg during control conditions (p < 0.01). The mean increase in LCP in patients with lymph edema was 3.4 +/- 4.1 mm Hg, and 1.7 +/- 2.0 mm Hg in healthy volunteers (NS). The maximum spread of the lymph capillary network in patients increased from 13.9 +/- 6.8 mm before congestion to 18.8 +/- 8.2 mm during thigh compression (p < 0.05). No increase could be observed in healthy subjects. In summary, venous and lymphatic congestion by cuff compression at the thigh level results in a significant increase in LCP in healthy volunteers as well as in patients with lymph edema. The increased spread of the contrast medium in the superficial microlymphatics in lymph edema patients indicates a compensatory mechanism for lymphatic drainage during congestion of the veins and lymph collectors of the leg. Copyright 2000 S. Karger AG, Basel

Buffer Management Simulation in ATM Networks

NASA Technical Reports Server (NTRS)

Yaprak, E.; Xiao, Y.; Chronopoulos, A.; Chow, E.; Anneberg, L.

1998-01-01

This paper presents a simulation of a new dynamic buffer allocation management scheme in ATM networks. To achieve this objective, an algorithm that detects congestion and updates the dynamic buffer allocation scheme was developed for the OPNET simulation package via the creation of a new ATM module.

A Minimax Network Flow Model for Characterizing the Impact of Slot Restrictions

NASA Technical Reports Server (NTRS)

Lee, Douglas W.; Patek, Stephen D.; Alexandrov, Natalia; Bass, Ellen J.; Kincaid, Rex K.

2010-01-01

This paper proposes a model for evaluating long-term measures to reduce congestion at airports in the National Airspace System (NAS). This model is constructed with the goal of assessing the global impacts of congestion management strategies, specifically slot restrictions. We develop the Minimax Node Throughput Problem (MINNTHRU), a multicommodity network flow model that provides insight into air traffic patterns when one minimizes the worst-case operation across all airports in a given network. MINNTHRU is thus formulated as a model where congestion arises from network topology. It reflects not market-driven airline objectives, but those of a regulatory authority seeking a distribution of air traffic beneficial to all airports, in response to congestion management measures. After discussing an algorithm for solving MINNTHRU for moderate-sized (30 nodes) and larger networks, we use this model to study the impacts of slot restrictions on the operation of an entire hub-spoke airport network. For both a small example network and a medium-sized network based on 30 airports in the NAS, we use MINNTHRU to demonstrate that increasing the severity of slot restrictions increases the traffic around unconstrained hub airports as well as the worst-case level of operation over all airports.

A dynamic feedback-control toll pricing methodology : a case study on Interstate 95 managed lanes.

DOT National Transportation Integrated Search

2013-06-01

Recently, congestion pricing emerged as a cost-effective and efficient strategy to mitigate the congestion problem on freeways. This study develops a feedback-control based dynamic toll approach to formulate and solve for optimal tolls. The study com...

Packet spacing : an enabling mechanism for delivering multimedia content in computational grids /

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

Feng, A. C.; Feng, W. C.; Belford, Geneva G.

2001-01-01

Streaming multimedia with UDP has become increasingly popular over distributed systems like the Internet. Scientific applications that stream multimedia include remote computational steering of visualization data and video-on-demand teleconferencing over the Access Grid. However, UDP does not possess a self-regulating, congestion-control mechanism; and most best-efort traflc is served by congestion-controlled TCF! Consequently, UDP steals bandwidth from TCP such that TCP$ows starve for network resources. With the volume of Internet traffic continuing to increase, the perpetuation of UDP-based streaming will cause the Internet to collapse as it did in the mid-1980's due to the use of non-congestion-controlled TCP. To address thismore » problem, we introduce the counterintuitive notion of inter-packet spacing with control feedback to enable UDP-based applications to perform well in the next-generation Internet and computational grids. When compared with traditional UDP-based streaming, we illustrate that our approach can reduce packet loss over SO% without adversely afecting delivered throughput. Keywords: network protocol, multimedia, packet spacing, streaming, TCI: UDlq rate-adjusting congestion control, computational grid, Access Grid.« less

CCS_WHMS: A Congestion Control Scheme for Wearable Health Management System.

PubMed

Kafi, Mohamed Amine; Ben Othman, Jalel; Bagaa, Miloud; Badache, Nadjib

2015-12-01

Wearable computing is becoming a more and more attracting field in the last years thanks to the miniaturisation of electronic devices. Wearable healthcare monitoring systems (WHMS) as an important client of wearable computing technology has gained a lot. Indeed, the wearable sensors and their surrounding healthcare applications bring a lot of benefits to patients, elderly people and medical staff, so facilitating their daily life quality. But from a research point of view, there is still work to accomplish in order to overcome the gap between hardware and software parts. In this paper, we target the problem of congestion control when all these healthcare sensed data have to reach the destination in a reliable manner that avoids repetitive transmission which wastes precious energy or leads to loss of important information in emergency cases, too. We propose a congestion control scheme CCS_WHMS that ensures efficient and fair data delivery while used in the body wearable system part or in the multi-hop inter bodies wearable ones to get the destination. As the congestion detection paradigm is very important in the control process, we do experimental tests to compare between state of the art congestion detection methods, using MICAz motes, in order to choose the appropriate one for our scheme.

Congestive heart failure in subjects with thyrotoxicosis in a black community

PubMed Central

Anakwue, R C; Onwubere, B J C; Anisiuba, B C; Ikeh, V O; Mbah, A; Ike, S O

2010-01-01

Introduction: Thyroid hormone has profound effects on a number of metabolic processes in virtually all tissues but the cardiovascular manifestations are prominent usually creating a hyperdynamic circulatory state. Thyrotoxicosis is not a common cause of congestive heart failure among black communities. Objectives: To determine the hospital prevalence, clinical characteristics and echocardiographic findings in patients with thyrotoxicosis who present with congestive heart failure (CCF) in the eastern part of Nigeria. Subjects and methods: A total of 50 subjects aged 15 years and above who were diagnosed as thyrotoxic following clinical and thyroid function tests were consecutively recruited. Fifty age- and sex-matched controls with no clinical or biochemical evidence of thyrotoxicosis and no comorbidities were used as controls. Two-dimensional echocardiography was carried out on all the subjects. CCF was determined clinically and echocardiographically. Results: Eight patients (5 females and 3 males) out of a total of 50 thyrotoxic patients presented with congestive heart failure. Conclusion: The study revealed that congestive heart failure can occur in thyrotoxicosis in spite of the associated hyperdynamic condition. The underlying mechanism may include direct damage by autoimmune myocarditis, congestive circulation secondary to excess sodium, and fluid retention. PMID:20730063

Containing air pollution and traffic congestion: Transport policy and the environment in Singapore

NASA Astrophysics Data System (ADS)

Chin, Anthony T. H.

Land transportation remains one of the main contributors of noise and air pollution in urban areas. This is in addition to traffic congestion and accidents which result in the loss of productive activity. While there is a close relationship between traffic volumes and levels of noise and air pollution, transport authorities often assume that solving traffic congestion would reduce noise and air pollutant levels. Tight control over automobile ownership and use in Singapore has contributed in improving traffic flows, travel speeds and air quality. The adoption of internationally accepted standards on automobile emissions and gasoline have been effective in reducing air pollution from motor vehicles. Demand management measures have largely focused on controlling the source of traffic congestion, i.e. private automobile ownership and its use especially within the Central Business District during the day. This paper reviews and analyzes the effectiveness of two measures which are instrumental in controlling congestion and automobile ownership, i.e. road pricing and the vehicle quota scheme (VQS). While these measures have been successful in achieving desired objectives, it has also led to the spreading of traffic externalities to other roads in the network, loss in consumer welfare and rent seeking by automobile traders.

On mobile wireless ad hoc IP video transports

NASA Astrophysics Data System (ADS)

Kazantzidis, Matheos

2006-05-01

Multimedia transports in wireless, ad-hoc, multi-hop or mobile networks must be capable of obtaining information about the network and adaptively tune sending and encoding parameters to the network response. Obtaining meaningful metrics to guide a stable congestion control mechanism in the transport (i.e. passive, simple, end-to-end and network technology independent) is a complex problem. Equally difficult is obtaining a reliable QoS metrics that agrees with user perception in a client/server or distributed environment. Existing metrics, objective or subjective, are commonly used after or before to test or report on a transmission and require access to both original and transmitted frames. In this paper, we propose that an efficient and successful video delivery and the optimization of overall network QoS requires innovation in a) a direct measurement of available and bottleneck capacity for its congestion control and b) a meaningful subjective QoS metric that is dynamically reported to video sender. Once these are in place, a binomial -stable, fair and TCP friendly- algorithm can be used to determine the sending rate and other packet video parameters. An adaptive mpeg codec can then continually test and fit its parameters and temporal-spatial data-error control balance using the perceived QoS dynamic feedback. We suggest a new measurement based on a packet dispersion technique that is independent of underlying network mechanisms. We then present a binomial control based on direct measurements. We implement a QoS metric that is known to agree with user perception (MPQM) in a client/server, distributed environment by using predetermined table lookups and characterization of video content.

Physics of Traffic Flow

NASA Astrophysics Data System (ADS)

Davis, L. C.

2015-03-01

The Texas A&M Transportation Institute estimated that traffic congestion cost the United States 121 billion in 2011 (the latest data available). The cost is due to wasted time and fuel. In addition to accidents and road construction, factors contributing to congestion include large demand, instability of high-density free flow and selfish behavior of drivers, which produces self-organized traffic bottlenecks. Extensive data collected on instrumented highways in various countries have led to a better understanding of traffic dynamics. From these measurements, Boris Kerner and colleagues developed a new theory called three-phase theory. They identified three major phases of flow observed in the data: free flow, synchronous flow and wide moving jams. The intermediate phase is called synchronous because vehicles in different lanes tend to have similar velocities. This congested phase, characterized by lower velocities yet modestly high throughput, frequently occurs near on-ramps and lane reductions. At present there are only two widely used methods of congestion mitigation: ramp metering and the display of current travel-time information to drivers. To find more effective methods to reduce congestion, researchers perform large-scale simulations using models based on the new theories. An algorithm has been proposed to realize Wardrop equilibria with real-time route information. Such equilibria have equal travel time on alternative routes between a given origin and destination. An active area of current research is the dynamics of connected vehicles, which communicate wirelessly with other vehicles and the surrounding infrastructure. These systems show great promise for improving traffic flow and safety.

Techniques for the Analysis of Spectral and Orbital Congestion in Space Systems.

DTIC Science & Technology

1984-03-01

Appendix 29 gives the appropriate equations ... .. - 87 - for the two cases, and provides algorithms for polarization isolation, I topocentric and geocentric ...The PDP form is maintained by MITRE Dept. D97, which provides services to run the program when staffing permits. NASA Lewis has used the results in a

On implementation of DCTCP on three-tier and fat-tree data center network topologies.

PubMed

Zafar, Saima; Bashir, Abeer; Chaudhry, Shafique Ahmad

2016-01-01

A data center is a facility for housing computational and storage systems interconnected through a communication network called data center network (DCN). Due to a tremendous growth in the computational power, storage capacity and the number of inter-connected servers, the DCN faces challenges concerning efficiency, reliability and scalability. Although transmission control protocol (TCP) is a time-tested transport protocol in the Internet, DCN challenges such as inadequate buffer space in switches and bandwidth limitations have prompted the researchers to propose techniques to improve TCP performance or design new transport protocols for DCN. Data center TCP (DCTCP) emerge as one of the most promising solutions in this domain which employs the explicit congestion notification feature of TCP to enhance the TCP congestion control algorithm. While DCTCP has been analyzed for two-tier tree-based DCN topology for traffic between servers in the same rack which is common in cloud applications, it remains oblivious to the traffic patterns common in university and private enterprise networks which traverse the complete network interconnect spanning upper tier layers. We also recognize that DCTCP performance cannot remain unaffected by the underlying DCN architecture hence there is a need to test and compare DCTCP performance when implemented over diverse DCN architectures. Some of the most notable DCN architectures are the legacy three-tier, fat-tree, BCube, DCell, VL2, and CamCube. In this research, we simulate the two switch-centric DCN architectures; the widely deployed legacy three-tier architecture and the promising fat-tree architecture using network simulator and analyze the performance of DCTCP in terms of throughput and delay for realistic traffic patterns. We also examine how DCTCP prevents incast and outcast congestion when realistic DCN traffic patterns are employed in above mentioned topologies. Our results show that the underlying DCN architecture significantly impacts DCTCP performance. We find that DCTCP gives optimal performance in fat-tree topology and is most suitable for large networks.

Input-Output Modeling and Control of the Departure Process of Congested Airports

NASA Technical Reports Server (NTRS)

Pujet, Nicolas; Delcaire, Bertrand; Feron, Eric

2003-01-01

A simple queueing model of busy airport departure operations is proposed. This model is calibrated and validated using available runway configuration and traffic data. The model is then used to evaluate preliminary control schemes aimed at alleviating departure traffic congestion on the airport surface. The potential impact of these control strategies on direct operating costs, environmental costs and overall delay is quantified and discussed.

Improving Simulated Annealing by Recasting it as a Non-Cooperative Game

NASA Technical Reports Server (NTRS)

Wolpert, David; Bandari, Esfandiar; Tumer, Kagan

2001-01-01

The game-theoretic field of COllective INtelligence (COIN) concerns the design of computer-based players engaged in a non-cooperative game so that as those players pursue their self-interests, a pre-specified global goal for the collective computational system is achieved "as a side-effect". Previous implementations of COIN algorithms have outperformed conventional techniques by up to several orders of magnitude, on domains ranging from telecommunications control to optimization in congestion problems. Recent mathematical developments have revealed that these previously developed game-theory-motivated algorithms were based on only two of the three factors determining performance. Consideration of only the third factor would instead lead to conventional optimization techniques like simulated annealing that have little to do with non-cooperative games. In this paper we present an algorithm based on all three terms at once. This algorithm can be viewed as a way to modify simulated annealing by recasting it as a non-cooperative game, with each variable replaced by a player. This recasting allows us to leverage the intelligent behavior of the individual players to substantially improve the exploration step of the simulated annealing. Experiments are presented demonstrating that this recasting improves simulated annealing by several orders of magnitude for spin glass relaxation and bin-packing.

Improved GSO Optimized ESN Soft-Sensor Model of Flotation Process Based on Multisource Heterogeneous Information Fusion

PubMed Central

Wang, Jie-sheng; Han, Shuang; Shen, Na-na

2014-01-01

For predicting the key technology indicators (concentrate grade and tailings recovery rate) of flotation process, an echo state network (ESN) based fusion soft-sensor model optimized by the improved glowworm swarm optimization (GSO) algorithm is proposed. Firstly, the color feature (saturation and brightness) and texture features (angular second moment, sum entropy, inertia moment, etc.) based on grey-level co-occurrence matrix (GLCM) are adopted to describe the visual characteristics of the flotation froth image. Then the kernel principal component analysis (KPCA) method is used to reduce the dimensionality of the high-dimensional input vector composed by the flotation froth image characteristics and process datum and extracts the nonlinear principal components in order to reduce the ESN dimension and network complex. The ESN soft-sensor model of flotation process is optimized by the GSO algorithm with congestion factor. Simulation results show that the model has better generalization and prediction accuracy to meet the online soft-sensor requirements of the real-time control in the flotation process. PMID:24982935

Cerebral blood flow in patients with congestive heart failure treated with captopril.

PubMed

Paulson, O B; Jarden, J O; Godtfredsen, J; Vorstrup, S

1984-05-31

The effect of captopril on cerebral blood flow was studied in five patients with severe congestive heart failure and in five control subjects. Cerebral blood flow was measured by inhalation of 133xenon and registration of its uptake and washout from the brain by single photon emission computer tomography. In addition, cerebral (internal jugular) venous oxygen tension was determined in the controls. The measurements were made before and 15, 60, and 180 minutes after a single oral dose of captopril (6.25 mg in patients with congestive heart failure and 25 mg in controls). Despite a marked decrease in blood pressure, cerebral blood flow increased slightly in the patients with severe congestive heart failure. When a correction was applied to take account of a change in arterial carbon dioxide tension, however, cerebral blood flow was unchanged after captopril administration even in patients with the greatest decrease in blood pressure, in whom a decrease in cerebral blood flow might have been expected. In the controls, blood pressure was little affected by captopril, whereas a slight, but not statistically significant, decrease in cerebral blood flow was observed. The cerebral venous oxygen tension decreased concomitantly.

Novel application of multi dynamic trend analysis as a sensitive tool for detecting the effects of aging and congestive heart failure on heart rate variability

NASA Astrophysics Data System (ADS)

Lin, Yu-Cheng; Lin, Yu-Hsuan; Lo, Men-Tzung; Peng, Chung-Kang; Huang, Norden E.; Yang, Cheryl C. H.; Kuo, Terry B. J.

2016-02-01

The complex fluctuations in heart rate variability (HRV) reflect cardiac autonomic modulation and are an indicator of congestive heart failure (CHF). This paper proposes a novel nonlinear approach to HRV investigation, the multi dynamic trend analysis (MDTA) method, based on the empirical mode decomposition algorithm of the Hilbert-Huang transform combined with a variable-sized sliding-window method. Electrocardiographic signal data obtained from the PhysioNet database were used. These data were from subjects with CHF (mean age = 59.4 ± 8.4), an age-matched elderly healthy control group (59.3 ± 10.6), and a healthy young group (30.3 ± 4.8); the HRVs of these subjects were processed using the MDTA method, time domain analysis, and frequency domain analysis. Among all HRV parameters, the MDTA absolute value slope (MDTS) and MDTA deviation (MDTD) exhibited the greatest area under the curve (AUC) of the receiver operating characteristics in distinguishing between the CHF group and the healthy controls (AUC = 1.000) and between the healthy elderly subject group and the young subject group (AUC = 0.834 ± 0.067 for MDTS; 0.837 ± 0.066 for MDTD). The CHF subjects presented with lower MDTA indices than those of the healthy elderly subject group. Furthermore, the healthy elderly subjects exhibited lower MDTA indices than those of the young controls. The MDTA method can adaptively and automatically identify the intrinsic fluctuation on variable temporal and spatial scales when investigating complex fluctuations in the cardiac autonomic regulation effects of aging and CHF.

Multicriteria meta-heuristics for AGV dispatching control based on computational intelligence.

PubMed

Naso, David; Turchiano, Biagio

2005-04-01

In many manufacturing environments, automated guided vehicles are used to move the processed materials between various pickup and delivery points. The assignment of vehicles to unit loads is a complex problem that is often solved in real-time with simple dispatching rules. This paper proposes an automated guided vehicles dispatching approach based on computational intelligence. We adopt a fuzzy multicriteria decision strategy to simultaneously take into account multiple aspects in every dispatching decision. Since the typical short-term view of dispatching rules is one of the main limitations of such real-time assignment heuristics, we also incorporate in the multicriteria algorithm a specific heuristic rule that takes into account the empty-vehicle travel on a longer time-horizon. Moreover, we also adopt a genetic algorithm to tune the weights associated to each decision criteria in the global decision algorithm. The proposed approach is validated by means of a comparison with other dispatching rules, and with other recently proposed multicriteria dispatching strategies also based on computational Intelligence. The analysis of the results obtained by the proposed dispatching approach in both nominal and perturbed operating conditions (congestions, faults) confirms its effectiveness.

Analysis of Aircraft Clusters to Measure Sector-Independent Airspace Congestion

NASA Technical Reports Server (NTRS)

Bilimoria, Karl D.; Lee, Hilda Q.

2005-01-01

The Distributed Air/Ground Traffic Management (DAG-TM) concept of operations* permits appropriately equipped aircraft to conduct Free Maneuvering operations. These independent aircraft have the freedom to optimize their trajectories in real time according to user preferences; however, they also take on the responsibility to separate themselves from other aircraft while conforming to any local Traffic Flow Management (TFM) constraints imposed by the air traffic service provider (ATSP). Examples of local-TFM constraints include temporal constraints such as a required time of arrival (RTA), as well as spatial constraints such as regions of convective weather, special use airspace, and congested airspace. Under current operations, congested airspace typically refers to a sector(s) that cannot accept additional aircraft due to controller workload limitations; hence Dynamic Density (a metric that is indicative of controller workload) can be used to quantify airspace congestion. However, for Free Maneuvering operations under DAG-TM, an additional metric is needed to quantify the airspace congestion problem from the perspective of independent aircraft. Such a metric would enable the ATSP to prevent independent aircraft from entering any local areas of congestion in which the flight deck based systems and procedures may not be able to ensure separation. This new metric, called Gaggle Density, offers the ATSP a mode of control to regulate normal operations and to ensure safety and stability during rare-normal or off-normal situations (e.g., system failures). It may be difficult to certify Free Maneuvering systems for unrestricted operations, but it may be easier to certify systems and procedures for specified levels of Gaggle Density that could be monitored by the ATSP, and maintained through relatively minor flow-rate (RTA type) restrictions. Since flight deck based separation assurance is airspace independent, the challenge is to measure congestion independent of sector boundaries. Figure 1 , reproduced from Ref. 1, depicts an example traffic situation. When the situation is analyzed by sector boundaries (left side of figure), a Dynamic Density metric would identify excessive congestion in the central sector. When the same traffic situation is analyzed independent of sector boundaries (right side of figure), a Gaggle Density metric would identify congestion in two dynamically defined areas covering portions of several sectors. The first step towards measuring airspace-independent congestion is to identify aircraft clusters, i.e., groups of closely spaced aircraft. The objective of this work is to develop techniques to detect and classify clusters of aircraft.

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

Eto, Joseph H.; Parashar, Manu; Lewis, Nancy Jo

The Real Time System Operations (RTSO) 2006-2007 project focused on two parallel technical tasks: (1) Real-Time Applications of Phasors for Monitoring, Alarming and Control; and (2) Real-Time Voltage Security Assessment (RTVSA) Prototype Tool. The overall goal of the phasor applications project was to accelerate adoption and foster greater use of new, more accurate, time-synchronized phasor measurements by conducting research and prototyping applications on California ISO's phasor platform - Real-Time Dynamics Monitoring System (RTDMS) -- that provide previously unavailable information on the dynamic stability of the grid. Feasibility assessment studies were conducted on potential application of this technology for small-signal stabilitymore » monitoring, validating/improving existing stability nomograms, conducting frequency response analysis, and obtaining real-time sensitivity information on key metrics to assess grid stress. Based on study findings, prototype applications for real-time visualization and alarming, small-signal stability monitoring, measurement based sensitivity analysis and frequency response assessment were developed, factory- and field-tested at the California ISO and at BPA. The goal of the RTVSA project was to provide California ISO with a prototype voltage security assessment tool that runs in real time within California ISO?s new reliability and congestion management system. CERTS conducted a technical assessment of appropriate algorithms, developed a prototype incorporating state-of-art algorithms (such as the continuation power flow, direct method, boundary orbiting method, and hyperplanes) into a framework most suitable for an operations environment. Based on study findings, a functional specification was prepared, which the California ISO has since used to procure a production-quality tool that is now a part of a suite of advanced computational tools that is used by California ISO for reliability and congestion management.« less

Congestion detection of pedestrians using the velocity entropy: A case study of Love Parade 2010 disaster

NASA Astrophysics Data System (ADS)

Huang, Lida; Chen, Tao; Wang, Yan; Yuan, Hongyong

2015-12-01

Gatherings of large human crowds often result in crowd disasters such as the Love Parade Disaster in Duisburg, Germany on July 24, 2010. To avoid these tragedies, video surveillance and early warning are becoming more and more significant. In this paper, the velocity entropy is first defined as the criterion for congestion detection, which represents the motion magnitude distribution and the motion direction distribution simultaneously. Then the detection method is verified by the simulation data based on AnyLogic software. To test the generalization performance of this method, video recordings of a real-world case, the Love Parade disaster, are also used in the experiments. The velocity histograms of the foreground object in the videos are extracted by the Gaussian Mixture Model (GMM) and optical flow computation. With a sequential change-point detection algorithm, the velocity entropy can be applied to detect congestions of the Love Parade festival. It turned out that without recognizing and tracking individual pedestrian, our method can detect abnormal crowd behaviors in real-time.

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...

Strengthening the resiliency of the coastal transportation system through integrated simulation of storm surge, inundation, and non-recurrent congestion in Northeast Florida.

DOT National Transportation Integrated Search

2013-05-01

In this study, the MTEVA (Developed as part of CMS #2009-010) has been advanced to apply storm surge and evacuation models to the greater Jacksonville area of Northeast Florida. Heuristic and time dynamic algorithms have been enhanced to work with th...

Clinical, double-blind, placebo-controlled study investigating the combination of acetylsalicylic acid and pseudoephedrine for the symptomatic treatment of nasal congestion associated with common cold.

PubMed

Loose, Irene; Winkel, Matthias

2004-01-01

It was the aim of this clinical study to demonstrate the efficacy of 1000 mg acetylsalicylic acid (ASA, CAS 50-78-2) in combination with 60 mg pseudoephedrine (PSE, CAS 90-82-4), compared with placebo, in the symptomatic treatment of nasal congestion associated with the common cold. A further aim was to demonstrate the efficacy of 500 mg ASA + 30 mg PSE and of 1000 mg paracetamol (CAS 103-90-2) + 60 mg PSE (active control) in the symptomatic treatment of nasal congestion. The study was designed as a randomized, two-center, double-blind, double-dummy, placebo-controlled, parallel-group, single-dose efficacy and safety trial over 6 h and was carried out in the USA. In total, at two centers, 643 patients who had a history and diagnosis of acute upper respiratory tract infection (URTI), were included; they showed symptoms such as nasal congestion, scratchy/sore throat, headache, generalized muscle ache, earache, runny nose, fever, sneezing etc. The investigational drugs ASA and PSE were both provided as granules in sachets and the granules were dissolved in water before administration; the combined preparation of paracetamol + PSE was administered as commercially available tablets encapsulated for blinding. For all preparations, matching placebos were provided. The primary efficacy variable was the area under the curve for differences from baseline on a nasal congestion scale in the first 2 h after treatment. To be eligible for the study, otherwise healthy volunteers were to present with nasal stuffiness of recent onset that reached a score of at least 6 on the 11-point scale for nasal congestion (0 = not stuffy, 10 = very stuffy). The primary analysis of the primary efficacy variable was calculated by analysis of variance including treatment group, severity (moderate/severe) and center as main strata. The analysis was performed using the intent-to-treat population. All active treatments proved to be statistically significantly superior to placebo with regard to the primary efficacy variable. Significant superiority of active treatment compared with placebo could also be demonstrated for an interval of up to 6 h after intake of the drug and for the relief of nasal congestion. The lower dose did not reveal significant different results compared with placebo for relief of nasal congestion in patients with a severe nasal congestion score at baseline. As well in patients with moderate nasal congestion score (NCS) at start of the study the difference from baseline in the NCS compared with placebo was not statistically significant. Thus a trend towards better efficacy in the higher dose could be assumed. No difference was found between 1000 mg ASA + 60 mg PSE and the active control. There were no differences between the two centers. The treatment proved to be safe and well tolerated, without relevant differences between the four treatment groups. Main adverse events were found to be related to the upper respiratory tract infection or were of gastrointestinal nature. In conclusion, the combination of ASA with PSE can be considered as an effective and safe remedial for the symptomatic treatment of the nasal congestion during URTI.

Market-Based Coordination of Thermostatically Controlled Loads—Part II: Unknown Parameters and Case Studies

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

Li, Sen; Zhang, Wei; Lian, Jianming

This two-part paper considers the coordination of a population of Thermostatically Controlled Loads (TCLs) with unknown parameters to achieve group objectives. The problem involves designing the bidding and market clearing strategy to motivate self-interested users to realize efficient energy allocation subject to a peak power constraint. The companion paper (Part I) formulates the problem and proposes a load coordination framework using the mechanism design approach. To address the unknown parameters, Part II of this paper presents a joint state and parameter estimation framework based on the expectation maximization algorithm. The overall framework is then validated using real-world weather data andmore » price data, and is compared with other approaches in terms of aggregated power response. Simulation results indicate that our coordination framework can effectively improve the efficiency of the power grid operations and reduce power congestion at key times.« less

The importance of antipersistence for traffic jams

NASA Astrophysics Data System (ADS)

Krause, Sebastian M.; Habel, Lars; Guhr, Thomas; Schreckenberg, Michael

2017-05-01

Universal characteristics of road networks and traffic patterns can help to forecast and control traffic congestion. The antipersistence of traffic flow time series has been found for many data sets, but its relevance for congestion has been overseen. Based on empirical data from motorways in Germany, we study how antipersistence of traffic flow time-series impacts the duration of traffic congestion on a wide range of time scales. We find a large number of short-lasting traffic jams, which implies a large risk for rear-end collisions.

Increased walking variability in elderly persons with congestive heart failure

NASA Technical Reports Server (NTRS)

Hausdorff, J. M.; Forman, D. E.; Ladin, Z.; Goldberger, A. L.; Rigney, D. R.; Wei, J. Y.

1994-01-01

OBJECTIVES: To determine the effects of congestive heart failure on a person's ability to walk at a steady pace while ambulating at a self-determined rate. SETTING: Beth Israel Hospital, Boston, a primary and tertiary teaching hospital, and a social activity center for elderly adults living in the community. PARTICIPANTS: Eleven elderly subjects (aged 70-93 years) with well compensated congestive heart failure (NY Heart Association class I or II), seven elderly subjects (aged 70-79 years) without congestive heart failure, and 10 healthy young adult subjects (aged 20-30 years). MEASUREMENTS: Subjects walked for 8 minutes on level ground at their own selected walking rate. Footswitches were used to measure the time between steps. Step rate (steps/minute) and step rate variability were calculated for the entire walking period, for 30 seconds during the first minute of the walk, for 30 seconds during the last minute of the walk, and for the 30-second period when each subject's step rate variability was minimal. Group means and 5% and 95% confidence intervals were computed. MAIN RESULTS: All measures of walking variability were significantly increased in the elderly subjects with congestive heart failure, intermediate in the elderly controls, and lowest in the young subjects. There was no overlap between the three groups using the minimal 30-second variability (elderly CHF vs elderly controls: P < 0.001, elderly controls vs young: P < 0.001), and no overlap between elderly subjects with and without congestive heart failure when using the overall variability. For all four measures, there was no overlap in any of the confidence intervals, and all group means were significantly different (P < 0.05).

Achieving Congestion Mitigation Using Distributed Power Control for Spectrum Sensor Nodes in Sensor Network-Aided Cognitive Radio Ad Hoc Networks

PubMed Central

Zhuo, Fan; Duan, Hucai

2017-01-01

The data sequence of spectrum sensing results injected from dedicated spectrum sensor nodes (SSNs) and the data traffic from upstream secondary users (SUs) lead to unpredictable data loads in a sensor network-aided cognitive radio ad hoc network (SN-CRN). As a result, network congestion may occur at a SU acting as fusion center when the offered data load exceeds its available capacity, which degrades network performance. In this paper, we present an effective approach to mitigate congestion of bottlenecked SUs via a proposed distributed power control framework for SSNs over a rectangular grid based SN-CRN, aiming to balance resource load and avoid excessive congestion. To achieve this goal, a distributed power control framework for SSNs from interior tier (IT) and middle tier (MT) is proposed to achieve the tradeoff between channel capacity and energy consumption. In particular, we firstly devise two pricing factors by considering stability of local spectrum sensing and spectrum sensing quality for SSNs. By the aid of pricing factors, the utility function of this power control problem is formulated by jointly taking into account the revenue of power reduction and the cost of energy consumption for IT or MT SSN. By bearing in mind the utility function maximization and linear differential equation constraint of energy consumption, we further formulate the power control problem as a differential game model under a cooperation or noncooperation scenario, and rigorously obtain the optimal solutions to this game model by employing dynamic programming. Then the congestion mitigation for bottlenecked SUs is derived by alleviating the buffer load over their internal buffers. Simulation results are presented to show the effectiveness of the proposed approach under the rectangular grid based SN-CRN scenario. PMID:28914803

A Loss Tolerant Rate Controller for Reliable Multicast

NASA Technical Reports Server (NTRS)

Montgomery, Todd

1997-01-01

This paper describes the design, specification, and performance of a Loss Tolerant Rate Controller (LTRC) for use in controlling reliable multicast senders. The purpose of this rate controller is not to adapt to congestion (or loss) on a per loss report basis (such as per received negative acknowledgment), but instead to use loss report information and perceived state to decide more prudent courses of action for both the short and long term. The goal of this controller is to be responsive to congestion, but not overly reactive to spurious independent loss. Performance of the controller is verified through simulation results.

Selective epidemic vaccination under the performant routing algorithms

NASA Astrophysics Data System (ADS)

Bamaarouf, O.; Alweimine, A. Ould Baba; Rachadi, A.; EZ-Zahraouy, H.

2018-04-01

Despite the extensive research on traffic dynamics and epidemic spreading, the effect of the routing algorithms strategies on the traffic-driven epidemic spreading has not received an adequate attention. It is well known that more performant routing algorithm strategies are used to overcome the congestion problem. However, our main result shows unexpectedly that these algorithms favor the virus spreading more than the case where the shortest path based algorithm is used. In this work, we studied the virus spreading in a complex network using the efficient path and the global dynamic routing algorithms as compared to shortest path strategy. Some previous studies have tried to modify the routing rules to limit the virus spreading, but at the expense of reducing the traffic transport efficiency. This work proposed a solution to overcome this drawback by using a selective vaccination procedure instead of a random vaccination used often in the literature. We found that the selective vaccination succeeded in eradicating the virus better than a pure random intervention for the performant routing algorithm strategies.

Traffic congestion and blood pressure elevation: A comparative cross-sectional study in Lebanon.

PubMed

Bou Samra, Patrick; El Tomb, Paul; Hosni, Mohammad; Kassem, Ahmad; Rizk, Robin; Shayya, Sami; Assaad, Sarah

2017-12-01

This comparative cross-sectional study examines the association between traffic congestion and elevation of systolic and/or diastolic blood pressure levels among a convenience sample of 310 drivers. Data collection took place during a gas station pause at a fixed time of day. Higher average systolic (142 vs 123 mm Hg) and diastolic (87 vs 78 mm Hg) blood pressures were detected among drivers exposed to traffic congestion compared with those who were not exposed (P<.001), while controlling for body mass index, age, sex, pack-year smoking, driving hours per week, and occupational driving. Moreover, among persons exposed to traffic congestion, longer exposure time was associated with higher systolic and diastolic blood pressures. Further studies are needed to better understand the mechanisms of the significant association between elevated blood pressure and traffic congestion. ©2017 Wiley Periodicals, Inc.

Using mobile probes to inform and measure the effectiveness of traffic control strategies on urban networks.

DOT National Transportation Integrated Search

2015-07-01

Urban traffic congestion is a problem that plagues many cities in the United States. Testing strategies to alleviate this : congestion is especially challenging due to the difficulty of modeling complex urban traffic networks. However, recent work ha...

Fiber-wireless for smart grid: A survey

NASA Astrophysics Data System (ADS)

Radzi, NAM; Ridwan, MA; Din, NM; Abdullah, F.; Mustafa, IS; l-Mansoori, MH

2017-11-01

Smart grid allows two-way communication between power utility companies and their customers while having the ability to sense along the transmission lines. However, the downside is such, when the smart devices are transmitting data simultaneously, it results in network congestion. Fiber wireless (FiWi) network is one of the best congestion solutions for smart grid up to date. In this paper, a survey of current literature on FiWi for smart grid will be reviewed and a testbed to test the protocols and algorithms for FiWi in smart grid will be proposed. The results of number of packets received and delay vs packet transmitted obtained via the testbed are compared with the results obtained via simulation and they show that they are in line with each other, validating the accuracy of the testbed.

Relationship Between Carbon Dioxide Levels and Reported Congestion and Headaches on the International Space Station

NASA Technical Reports Server (NTRS)

Cole, Robert; Wear, Mary; Young, Millennia; Cobel, Christopher; Mason, Sara

2017-01-01

Congestion is commonly reported during spaceflight, and most crewmembers have reported using medications for congestion during International Space Station (ISS) missions. Although congestion has been attributed to fluid shifts during spaceflight, fluid status reaches equilibrium during the first week after launch while congestion continues to be reported throughout long duration missions. Congestion complaints have anecdotally been reported in relation to ISS CO2 levels; this evaluation was undertaken to determine whether or not an association exists. METHODS: Reported headaches, congestion symptoms, and CO2 levels were obtained for ISS expeditions 2-31, and time-weighted means and single-point maxima were determined for 24-hour (24hr) and 7-day (7d) periods prior to each weekly private medical conference. Multiple imputation addressed missing data, and logistic regression modeled the relationship between probability of reported event of congestion or headache and CO2 levels, adjusted for possible confounding covariates. The first seven days of spaceflight were not included to control for fluid shifts. Data were evaluated to determine the concentration of CO2 required to maintain the risk of congestion below 1% to allow for direct comparison with a previously published evaluation of CO2 concentrations and headache. RESULTS: This study confirmed a previously identified significant association between CO2 and headache and also found a significant association between CO2 and congestion. For each 1-mm Hg increase in CO2, the odds of a crew member reporting congestion doubled. The average 7-day CO2 would need to be maintained below 1.5 mmHg to keep the risk of congestion below 1%. The predicted probability curves of ISS headache and congestion curves appear parallel when plotted against ppCO2 levels with congestion occurring at approximately 1mmHg lower than a headache would be reported. DISCUSSION: While the cause of congestion is multifactorial, this study showed congestion is associated with CO2 levels on ISS. Data from additional expeditions could be incorporated to further assess this finding. CO2 levels are also associated with reports of headaches on ISS. While it may be expected for astronauts with congestion to also complain of headaches, these two symptoms are commonly mutually exclusive. Furthermore, it is unknown if a temporal CO2 relationship exists between congestion and headache on ISS. CO2 levels were time-weighted for 24hr and 7d, and thus the time course of congestion leading to headache was not assessed; however, congestion could be an early CO2-related symptom when compared to headache. Future studies evaluating the association of CO2-related congestion leading to headache would be difficult due to the relatively stable daily CO2 levels on ISS currently, but a systematic study could be implemented on-orbit if desired.

Applied Distributed Model Predictive Control for Energy Efficient Buildings and Ramp Metering

NASA Astrophysics Data System (ADS)

Koehler, Sarah Muraoka

Industrial large-scale control problems present an interesting algorithmic design challenge. A number of controllers must cooperate in real-time on a network of embedded hardware with limited computing power in order to maximize system efficiency while respecting constraints and despite communication delays. Model predictive control (MPC) can automatically synthesize a centralized controller which optimizes an objective function subject to a system model, constraints, and predictions of disturbance. Unfortunately, the computations required by model predictive controllers for large-scale systems often limit its industrial implementation only to medium-scale slow processes. Distributed model predictive control (DMPC) enters the picture as a way to decentralize a large-scale model predictive control problem. The main idea of DMPC is to split the computations required by the MPC problem amongst distributed processors that can compute in parallel and communicate iteratively to find a solution. Some popularly proposed solutions are distributed optimization algorithms such as dual decomposition and the alternating direction method of multipliers (ADMM). However, these algorithms ignore two practical challenges: substantial communication delays present in control systems and also problem non-convexity. This thesis presents two novel and practically effective DMPC algorithms. The first DMPC algorithm is based on a primal-dual active-set method which achieves fast convergence, making it suitable for large-scale control applications which have a large communication delay across its communication network. In particular, this algorithm is suited for MPC problems with a quadratic cost, linear dynamics, forecasted demand, and box constraints. We measure the performance of this algorithm and show that it significantly outperforms both dual decomposition and ADMM in the presence of communication delay. The second DMPC algorithm is based on an inexact interior point method which is suited for nonlinear optimization problems. The parallel computation of the algorithm exploits iterative linear algebra methods for the main linear algebra computations in the algorithm. We show that the splitting of the algorithm is flexible and can thus be applied to various distributed platform configurations. The two proposed algorithms are applied to two main energy and transportation control problems. The first application is energy efficient building control. Buildings represent 40% of energy consumption in the United States. Thus, it is significant to improve the energy efficiency of buildings. The goal is to minimize energy consumption subject to the physics of the building (e.g. heat transfer laws), the constraints of the actuators as well as the desired operating constraints (thermal comfort of the occupants), and heat load on the system. In this thesis, we describe the control systems of forced air building systems in practice. We discuss the "Trim and Respond" algorithm which is a distributed control algorithm that is used in practice, and show that it performs similarly to a one-step explicit DMPC algorithm. Then, we apply the novel distributed primal-dual active-set method and provide extensive numerical results for the building MPC problem. The second main application is the control of ramp metering signals to optimize traffic flow through a freeway system. This application is particularly important since urban congestion has more than doubled in the past few decades. The ramp metering problem is to maximize freeway throughput subject to freeway dynamics (derived from mass conservation), actuation constraints, freeway capacity constraints, and predicted traffic demand. In this thesis, we develop a hybrid model predictive controller for ramp metering that is guaranteed to be persistently feasible and stable. This contrasts to previous work on MPC for ramp metering where such guarantees are absent. We apply a smoothing method to the hybrid model predictive controller and apply the inexact interior point method to this nonlinear non-convex ramp metering problem.

Integrated risk/cost planning models for the US Air Traffic system

NASA Technical Reports Server (NTRS)

Mulvey, J. M.; Zenios, S. A.

1985-01-01

A prototype network planning model for the U.S. Air Traffic control system is described. The model encompasses the dual objectives of managing collision risks and transportation costs where traffic flows can be related to these objectives. The underlying structure is a network graph with nonseparable convex costs; the model is solved efficiently by capitalizing on its intrinsic characteristics. Two specialized algorithms for solving the resulting problems are described: (1) truncated Newton, and (2) simplicial decomposition. The feasibility of the approach is demonstrated using data collected from a control center in the Midwest. Computational results with different computer systems are presented, including a vector supercomputer (CRAY-XMP). The risk/cost model has two primary uses: (1) as a strategic planning tool using aggregate flight information, and (2) as an integrated operational system for forecasting congestion and monitoring (controlling) flow throughout the U.S. In the latter case, access to a supercomputer is required due to the model's enormous size.

Using mobile probes to inform and measure the effectiveness of macroscopic traffic control strategies on urban networks.

DOT National Transportation Integrated Search

2015-06-01

Urban traffic congestion is a problem that plagues many cities in the United States. Testing strategies to alleviate this : congestion is especially challenging due to the difficulty of modeling complex urban traffic networks. However, recent work ha...

A novel communication mechanism based on node potential multi-path routing

NASA Astrophysics Data System (ADS)

Bu, Youjun; Zhang, Chuanhao; Jiang, YiMing; Zhang, Zhen

2016-10-01

With the network scales rapidly and new network applications emerge frequently, bandwidth supply for today's Internet could not catch up with the rapid increasing requirements. Unfortunately, irrational using of network sources makes things worse. Actual network deploys single-next-hop optimization paths for data transmission, but such "best effort" model leads to the imbalance use of network resources and usually leads to local congestion. On the other hand Multi-path routing can use the aggregation bandwidth of multi paths efficiently and improve the robustness of network, security, load balancing and quality of service. As a result, multi-path has attracted much attention in the routing and switching research fields and many important ideas and solutions have been proposed. This paper focuses on implementing the parallel transmission of multi next-hop data, balancing the network traffic and reducing the congestion. It aimed at exploring the key technologies of the multi-path communication network, which could provide a feasible academic support for subsequent applications of multi-path communication networking. It proposed a novel multi-path algorithm based on node potential in the network. And the algorithm can fully use of the network link resource and effectively balance network link resource utilization.

Improving Simulated Annealing by Replacing Its Variables with Game-Theoretic Utility Maximizers

NASA Technical Reports Server (NTRS)

Wolpert, David H.; Bandari, Esfandiar; Tumer, Kagan

2001-01-01

The game-theory field of Collective INtelligence (COIN) concerns the design of computer-based players engaged in a non-cooperative game so that as those players pursue their self-interests, a pre-specified global goal for the collective computational system is achieved as a side-effect. Previous implementations of COIN algorithms have outperformed conventional techniques by up to several orders of magnitude, on domains ranging from telecommunications control to optimization in congestion problems. Recent mathematical developments have revealed that these previously developed algorithms were based on only two of the three factors determining performance. Consideration of only the third factor would instead lead to conventional optimization techniques like simulated annealing that have little to do with non-cooperative games. In this paper we present an algorithm based on all three terms at once. This algorithm can be viewed as a way to modify simulated annealing by recasting it as a non-cooperative game, with each variable replaced by a player. This recasting allows us to leverage the intelligent behavior of the individual players to substantially improve the exploration step of the simulated annealing. Experiments are presented demonstrating that this recasting significantly improves simulated annealing for a model of an economic process run over an underlying small-worlds topology. Furthermore, these experiments reveal novel small-worlds phenomena, and highlight the shortcomings of conventional mechanism design in bounded rationality domains.

A constrained joint source/channel coder design and vector quantization of nonstationary sources

NASA Technical Reports Server (NTRS)

Sayood, Khalid; Chen, Y. C.; Nori, S.; Araj, A.

1993-01-01

The emergence of broadband ISDN as the network for the future brings with it the promise of integration of all proposed services in a flexible environment. In order to achieve this flexibility, asynchronous transfer mode (ATM) has been proposed as the transfer technique. During this period a study was conducted on the bridging of network transmission performance and video coding. The successful transmission of variable bit rate video over ATM networks relies on the interaction between the video coding algorithm and the ATM networks. Two aspects of networks that determine the efficiency of video transmission are the resource allocation algorithm and the congestion control algorithm. These are explained in this report. Vector quantization (VQ) is one of the more popular compression techniques to appear in the last twenty years. Numerous compression techniques, which incorporate VQ, have been proposed. While the LBG VQ provides excellent compression, there are also several drawbacks to the use of the LBG quantizers including search complexity and memory requirements, and a mismatch between the codebook and the inputs. The latter mainly stems from the fact that the VQ is generally designed for a specific rate and a specific class of inputs. In this work, an adaptive technique is proposed for vector quantization of images and video sequences. This technique is an extension of the recursively indexed scalar quantization (RISQ) algorithm.

Incident Management, Fast-Trac, Phase Iib Deliverables, #20. The Model Analysis Report On The Benefits Of Scats In Alleviating The Impacts Of Incidents

DOT National Transportation Integrated Search

1996-01-01

FAST-TRAC : SELECTING THE MOST APPROPRIATE TRAFFIC CONTROL STRATEGY FOR INCIDENT CONGESTION MANAGEMENT CAN HAVE A MAJOR IMPACT ON THE EXTENT AND DURATION OF THE RESULTING CONGESTION. THIS RESEARCH INVESTIGATED THE EFFECTIVENESSES OF SEVERAL CONTRO...

Frame Transmission Efficiency-Based Cross-Layer Congestion Notification Scheme in Wireless Ad Hoc Networks.

PubMed

He, Huaguang; Li, Taoshen; Feng, Luting; Ye, Jin

2017-07-15

Different from the traditional wired network, the fundamental cause of transmission congestion in wireless ad hoc networks is medium contention. How to utilize the congestion state from the MAC (Media Access Control) layer to adjust the transmission rate is core work for transport protocol design. However, recent works have shown that the existing cross-layer congestion detection solutions are too complex to be deployed or not able to characterize the congestion accurately. We first propose a new congestion metric called frame transmission efficiency (i.e., the ratio of successful transmission delay to the frame service delay), which describes the medium contention in a fast and accurate manner. We further present the design and implementation of RECN (ECN and the ratio of successful transmission delay to the frame service delay in the MAC layer, namely, the frame transmission efficiency), a general supporting scheme that adjusts the transport sending rate through a standard ECN (Explicit Congestion Notification) signaling method. Our method can be deployed on commodity switches with small firmware updates, while making no modification on end hosts. We integrate RECN transparently (i.e., without modification) with TCP on NS2 simulation. The experimental results show that RECN remarkably improves network goodput across multiple concurrent TCP flows.

Software Tools to Support Research on Airport Departure Planning

NASA Technical Reports Server (NTRS)

Carr, Francis; Evans, Antony; Feron, Eric; Clarke, John-Paul

2003-01-01

A simple, portable and useful collection of software tools has been developed for the analysis of airport surface traffic. The tools are based on a flexible and robust traffic-flow model, and include calibration, validation and simulation functionality for this model. Several different interfaces have been developed to help promote usage of these tools, including a portable Matlab(TM) implementation of the basic algorithms; a web-based interface which provides online access to automated analyses of airport traffic based on a database of real-world operations data which covers over 250 U.S. airports over a 5-year period; and an interactive simulation-based tool currently in use as part of a college-level educational module. More advanced applications for airport departure traffic include taxi-time prediction and evaluation of "windowing" congestion control.

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.

Impact of traffic congestion on road accidents: a spatial analysis of the M25 motorway in England.

PubMed

Wang, Chao; Quddus, Mohammed A; Ison, Stephen G

2009-07-01

Traffic congestion and road accidents are two external costs of transport and the reduction of their impacts is often one of the primary objectives for transport policy makers. The relationship between traffic congestion and road accidents however is not apparent and less studied. It is speculated that there may be an inverse relationship between traffic congestion and road accidents, and as such this poses a potential dilemma for transport policy makers. This study aims to explore the impact of traffic congestion on the frequency of road accidents using a spatial analysis approach, while controlling for other relevant factors that may affect road accidents. The M25 London orbital motorway, divided into 70 segments, was chosen to conduct this study and relevant data on road accidents, traffic and road characteristics were collected. A robust technique has been developed to map M25 accidents onto its segments. Since existing studies have often used a proxy to measure the level of congestion, this study has employed a precise congestion measurement. A series of Poisson based non-spatial (such as Poisson-lognormal and Poisson-gamma) and spatial (Poisson-lognormal with conditional autoregressive priors) models have been used to account for the effects of both heterogeneity and spatial correlation. The results suggest that traffic congestion has little or no impact on the frequency of road accidents on the M25 motorway. All other relevant factors have provided results consistent with existing studies.

Recommendations for pacemaker implantation for the treatment of atrial tachyarrhythmias and resynchronisation therapy for heart failure

PubMed Central

van Hemel, N.M.; Dijkman, B.; de Voogt, W.G.; Beukema, W.P.; Bosker, H.A.; de Cock, C.C.; Jordaens, L.J.L.M.; van Gelder, I.C.; van Gelder, L.M.; van Mechelen, R.; Ruiter, J.H.; Sedney, M.I.; Slegers, L.C.

2004-01-01

Today, new pacing algorithms and stimulation methods for the prevention and interruption of atrial tachyarrhythmias can be applied on patients who need bradycardia pacing for conventional reasons. In addition, biventricular pacing as additive treatment for patients with severe congestive heart failure due to ventricular systolic dysfunction and prolonged intraventricular conduction has shown to improve symptoms and reduce hospital admissions. These new pacing technologies and the optimising of the pacing programmes are complex, expensive and time-consuming. Based on many clinical studies the indications for these devices are beginning to emerge. To support the cardiologist's decision-making and to prevent waste of effort and resources, the 'ad hoc committee' has provided preliminary recommendations for implantable devices to treat atrial tachyarrhythmias and to extend the treatment of congestive heart failure respectively. PMID:25696255

Infinite horizon optimal impulsive control with applications to Internet congestion control

NASA Astrophysics Data System (ADS)

Avrachenkov, Konstantin; Habachi, Oussama; Piunovskiy, Alexey; Zhang, Yi

2015-04-01

We investigate infinite-horizon deterministic optimal control problems with both gradual and impulsive controls, where any finitely many impulses are allowed simultaneously. Both discounted and long-run time-average criteria are considered. We establish very general and at the same time natural conditions, under which the dynamic programming approach results in an optimal feedback policy. The established theoretical results are applied to the Internet congestion control, and by solving analytically and nontrivially the underlying optimal control problems, we obtain a simple threshold-based active queue management scheme, which takes into account the main parameters of the transmission control protocols, and improves the fairness among the connections in a given network.

A parallel computing engine for a class of time critical processes.

PubMed

Nabhan, T M; Zomaya, A Y

1997-01-01

This paper focuses on the efficient parallel implementation of systems of numerically intensive nature over loosely coupled multiprocessor architectures. These analytical models are of significant importance to many real-time systems that have to meet severe time constants. A parallel computing engine (PCE) has been developed in this work for the efficient simplification and the near optimal scheduling of numerical models over the different cooperating processors of the parallel computer. First, the analytical system is efficiently coded in its general form. The model is then simplified by using any available information (e.g., constant parameters). A task graph representing the interconnections among the different components (or equations) is generated. The graph can then be compressed to control the computation/communication requirements. The task scheduler employs a graph-based iterative scheme, based on the simulated annealing algorithm, to map the vertices of the task graph onto a Multiple-Instruction-stream Multiple-Data-stream (MIMD) type of architecture. The algorithm uses a nonanalytical cost function that properly considers the computation capability of the processors, the network topology, the communication time, and congestion possibilities. Moreover, the proposed technique is simple, flexible, and computationally viable. The efficiency of the algorithm is demonstrated by two case studies with good results.

Airborne Network Optimization with Dynamic Network Update

DTIC Science & Technology

2015-03-26

Faculty Department of Electrical and Computer Engineering Graduate School of Engineering and Management Air Force Institute of Technology Air University...Member Dr. Barry E. Mullins Member AFIT-ENG-MS-15-M-030 Abstract Modern networks employ congestion and routing management algorithms that can perform...airborne networks. Intelligent agents can make use of Kalman filter predictions to make informed decisions to manage communication in airborne networks. The

Limb congestion enhances the synchronization of sympathetic outflow with muscle contraction

NASA Technical Reports Server (NTRS)

Mostoufi-Moab, S.; Herr, M. D.; Silber, D. H.; Gray, K. S.; Leuenberger, U. A.; Sinoway, L. I.

2000-01-01

In this report, we examined if the synchronization of muscle sympathetic nerve activity (MSNA) with muscle contraction is enhanced by limb congestion. To explore this relationship, we applied signal-averaging techniques to the MSNA signal obtained during short bouts of forearm contraction (2-s contraction/3-s rest cycle) at 40% maximal voluntary contraction for 5 min. We performed this analysis before and after forearm venous congestion; an intervention that augments the autonomic response to sustained static muscle contractions via a local effect on muscle afferents. There was an increased percentage of the MSNA noted during second 2 of the 5-s contraction/rest cycles. The percentage of total MSNA seen during this particular second increased from minute 1 to 5 of contraction and was increased further by limb congestion (control minute 1 = 25.6 +/- 2.0%, minute 5 = 32.8 +/- 2.2%; limb congestion minute 1 = 29.3 +/- 2.1%, minute 5 = 37.8 +/- 3.9%; exercise main effect <0.005; limb congestion main effect P = 0.054). These changes in the distribution of signal-averaged MSNA were seen despite the fact that the mean number of sympathetic discharges did not increase over baseline. We conclude that synchronization of contraction and MSNA is seen during short repetitive bouts of handgrip. The sensitizing effect of contraction time and limb congestion are apparently due to feedback from muscle afferents within the exercising muscle.

Models and methods for assessing the value of HVDC and MVDC technologies in modern power grids

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

Makarov, Yuri V.; Elizondo, Marcelo A.; O'Brien, James G.

This report reflects the results of U.S. Department of Energy’s (DOE) Grid Modernization project 0074 “Models and methods for assessing the value of HVDC [high-voltage direct current] and MTDC [multi-terminal direct current] technologies in modern power grids.” The work was done by the Pacific Northwest National Laboratory (PNNL) and Oak Ridge National Laboratory (ORNL) in cooperation with Mid-Continent Independent System Operator (MISO) and Siemens. The main motivation of this study was to show the benefit of using direct current (DC) systems larger than those in existence today as they overlap with the alternating current (AC) systems. Proper use of theirmore » flexibility in terms of active/reactive power control and fast response can provide much-needed services to the grid at the same time as moving large blocks of energy to take advantage of cost diversity. Ultimately, the project’s success will enable decision-makers and investors to make well-informed decisions regarding this use of DC systems. This project showed the technical feasibility of HVDC macrogrid for frequency control and congestion relief in addition to bulk power transfers. Industry-established models for commonly used technologies were employed, along with high-fidelity models for recently developed HVDC converter technologies; like the modular multilevel converters (MMCs), a voltage source converters (VSC). Models for General Electric Positive Sequence Load Flow (GE PSLF) and Siemens Power System Simulator (PSS/E), widely used analysis programs, were for the first time adapted to include at the same time both Western Electricity Coordinating Council (WECC) and Eastern Interconnection (EI), the two largest North American interconnections. The high-fidelity models and their control were developed in detail for MMC system and extended to HVDC systems in point-to-point and in three-node multi-terminal configurations. Using a continental-level mixed AC-DC grid model, and using a HVDC macrogrid power flow and transient stability model, the results showed that the HVDC macrogrid relieved congestion and mitigated loop flows in AC networks, and provided up to 24% improvement in frequency responses. These are realistic studies, based on the 2025 heavy summer and EI multi-regional modeling working group (MMWG) 2026 summer peak cases. This work developed high-fidelity models and simulation algorithms to understand the dynamics of MMC. The developed models and simulation algorithms are up to 25 times faster than the existing algorithms. Models and control algorithms for high-fidelity models were designed and tested for point-to-point and multi-terminal configurations. The multi-terminal configuration was tested connecting simplified models of EI, WI, and Electric Reliability Council of Texas (ERCOT). The developed models showed up to 45% improvement in frequency response with the connection of all the three asynchronous interconnections in the United States using fast and advanced DC technologies like the multi-terminal MMC-DC system. Future work will look into developing high-fidelity models of other advanced DC technologies, combining high-fidelity models with the continental-level model, incorporating additional services. More scenarios involving large-scale HVDC and MTDC will be evaluated.« less

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

Paulson, O.B.; Jarden, J.O.; Godtfredsen, J.

The effect of captopril on cerebral blood flow was studied in five patients with severe congestive heart failure and in five control subjects. Cerebral blood flow was measured by inhalation of /sup 133/xenon and registration of its uptake and washout from the brain by single photon emission computer tomography. In addition, cerebral (internal jugular) venous oxygen tension was determined in the controls. The measurements were made before and 15, 60, and 180 minutes after a single oral dose of captopril (6.25 mg in patients with congestive heart failure and 25 mg in controls). Despite a marked decrease in blood pressure,more » cerebral blood flow increased slightly in the patients with severe congestive heart failure. When a correction was applied to take account of a change in arterial carbon dioxide tension, however, cerebral blood flow was unchanged after captopril administration even in patients with the greatest decrease in blood pressure, in whom a decrease in cerebral blood flow might have been expected. In the controls, blood pressure was little affected by captopril, whereas a slight, but not statistically significant, decrease in cerebral blood flow was observed. The cerebral venous oxygen tension decreased concomitantly.« less

Recommendations for pacemaker implantation for the treatment of atrial tachyarrhythmias and resynchronisation therapy for heart failure: A report from the task force on pacemaker indications of the Dutch Working Group on Cardiac Pacing.

PubMed

van Hemel, N M; Dijkman, B; de Voogt, W G; Beukema, W P; Bosker, H A; de Cock, C C; Jordaens, L J L M; van Gelder, I C; van Gelder, L M; van Mechelen, R; Ruiter, J H; Sedney, M I; Slegers, L C

2004-01-01

Today, new pacing algorithms and stimulation methods for the prevention and interruption of atrial tachyarrhythmias can be applied on patients who need bradycardia pacing for conventional reasons. In addition, biventricular pacing as additive treatment for patients with severe congestive heart failure due to ventricular systolic dysfunction and prolonged intraventricular conduction has shown to improve symptoms and reduce hospital admissions. These new pacing technologies and the optimising of the pacing programmes are complex, expensive and time-consuming. Based on many clinical studies the indications for these devices are beginning to emerge. To support the cardiologist's decision-making and to prevent waste of effort and resources, the 'ad hoc committee' has provided preliminary recommendations for implantable devices to treat atrial tachyarrhythmias and to extend the treatment of congestive heart failure respectively.

A data-driven feature extraction framework for predicting the severity of condition of congestive heart failure patients.

PubMed

Sideris, Costas; Alshurafa, Nabil; Pourhomayoun, Mohammad; Shahmohammadi, Farhad; Samy, Lauren; Sarrafzadeh, Majid

2015-01-01

In this paper, we propose a novel methodology for utilizing disease diagnostic information to predict severity of condition for Congestive Heart Failure (CHF) patients. Our methodology relies on a novel, clustering-based, feature extraction framework using disease diagnostic information. To reduce the dimensionality we identify disease clusters using cooccurence frequencies. We then utilize these clusters as features to predict patient severity of condition. We build our clustering and feature extraction algorithm using the 2012 National Inpatient Sample (NIS), Healthcare Cost and Utilization Project (HCUP) which contains 7 million discharge records and ICD-9-CM codes. The proposed framework is tested on Ronald Reagan UCLA Medical Center Electronic Health Records (EHR) from 3041 patients. We compare our cluster-based feature set with another that incorporates the Charlson comorbidity score as a feature and demonstrate an accuracy improvement of up to 14% in the predictability of the severity of condition.

Analysis Balance Parameter of Optimal Ramp metering

NASA Astrophysics Data System (ADS)

Li, Y.; Duan, N.; Yang, X.

2018-05-01

Ramp metering is a motorway control method to avoid onset congestion through limiting the access of ramp inflows into the main road of the motorway. The optimization model of ramp metering is developed based upon cell transmission model (CTM). With the piecewise linear structure of CTM, the corresponding motorway traffic optimization problem can be formulated as a linear programming (LP) problem. It is known that LP problem can be solved by established solution algorithms such as SIMPLEX or interior-point methods for the global optimal solution. The commercial software (CPLEX) is adopted in this study to solve the LP problem within reasonable computational time. The concept is illustrated through a case study of the United Kingdom M25 Motorway. The optimal solution provides useful insights and guidances on how to manage motorway traffic in order to maximize the corresponding efficiency.

CONGESTIVE HEART FAILURE ASSOCIATED WITH PREGNANCY IN OKAPI (OKAPIA JOHNSTONI).

PubMed

Warren, Joshua D; Aitken-Palmer, Copper; Weldon, Alan D; Flanagan, Joseph P; Howard, Lauren L; Garner, Michael M; Citino, Scott B

2017-03-01

Acute signs associated with cardiovascular disease occurred in three pregnant okapi ( Okapia johnstoni ) during early to midgestation and progressed to congestive heart failure. Congestive heart failure was diagnosed antemortem using echocardiography and plasma cardiac troponin levels. Clinical signs included decreased activity, hyporexia, tachypnea, dyspnea, flared nostrils, and productive coughing with copious amounts of foamy nasal discharge. Parenteral and oral treatment with furosemide, enalapril, and spironolactone controlled clinical signs in the three okapi allowing each to carry out one pregnancy to term. Two okapi carried the first pregnancy to term after showing signs, while one okapi aborted the first calf and gave birth to a healthy calf in a subsequent pregnancy. Subsequent pregnancy in one okapi ended with abortion and associated dystocia and endometritis. Following parturition, clinical signs associated with heart failure resolved in all three individuals; serial echocardiography in two individuals showed improvement in fractional shortening and left atrial size and all three okapi showed markedly decreased pleural effusion and resolution of pulmonary edema. However, subsequent pregnancies in all three okapi induced respiratory distress and recurrence of congestive heart failure; one okapi died from congestive heart failure associated with subsequent pregnancy. This case series describes the clinical presentation and pathologic findings of congestive heart failure during pregnancy in adult okapi.

Increasing Intelligence in Inter-Vehicle Communications to Reduce Traffic Congestions: Experiments in Urban and Highway Environments.

PubMed

Meneguette, Rodolfo I; Filho, Geraldo P R; Guidoni, Daniel L; Pessin, Gustavo; Villas, Leandro A; Ueyama, Jó

2016-01-01

Intelligent Transportation Systems (ITS) rely on Inter-Vehicle Communication (IVC) to streamline the operation of vehicles by managing vehicle traffic, assisting drivers with safety and sharing information, as well as providing appropriate services for passengers. Traffic congestion is an urban mobility problem, which causes stress to drivers and economic losses. In this context, this work proposes a solution for the detection, dissemination and control of congested roads based on inter-vehicle communication, called INCIDEnT. The main goal of the proposed solution is to reduce the average trip time, CO emissions and fuel consumption by allowing motorists to avoid congested roads. The simulation results show that our proposed solution leads to short delays and a low overhead. Moreover, it is efficient with regard to the coverage of the event and the distance to which the information can be propagated. The findings of the investigation show that the proposed solution leads to (i) high hit rate in the classification of the level of congestion, (ii) a reduction in average trip time, (iii) a reduction in fuel consumption, and (iv) reduced CO emissions.

Increasing Intelligence in Inter-Vehicle Communications to Reduce Traffic Congestions: Experiments in Urban and Highway Environments

PubMed Central

Filho, Geraldo P. R.; Guidoni, Daniel L.; Pessin, Gustavo; Villas, Leandro A.; Ueyama, Jó

2016-01-01

Intelligent Transportation Systems (ITS) rely on Inter-Vehicle Communication (IVC) to streamline the operation of vehicles by managing vehicle traffic, assisting drivers with safety and sharing information, as well as providing appropriate services for passengers. Traffic congestion is an urban mobility problem, which causes stress to drivers and economic losses. In this context, this work proposes a solution for the detection, dissemination and control of congested roads based on inter-vehicle communication, called INCIDEnT. The main goal of the proposed solution is to reduce the average trip time, CO emissions and fuel consumption by allowing motorists to avoid congested roads. The simulation results show that our proposed solution leads to short delays and a low overhead. Moreover, it is efficient with regard to the coverage of the event and the distance to which the information can be propagated. The findings of the investigation show that the proposed solution leads to (i) high hit rate in the classification of the level of congestion, (ii) a reduction in average trip time, (iii) a reduction in fuel consumption, and (iv) reduced CO emissions PMID:27526048

Plasmapheresis affects responses of slowly and rapidly adapting airway receptors to pulmonary venous congestion in dogs.

PubMed Central

Kappagoda, C T; Ravi, K

1989-01-01

1. The effects of plasmapheresis on the responses of rapidly adapting receptors (RARs) and slowly adapting receptors (SARs) of the airways to pulmonary venous congestion were examined in dogs anaesthetized with alpha-chloralose. Pulmonary venous congestion was produced in a graded manner by partial obstruction of the mitral valve sufficient to raise the mean left atrial pressure by 5, 10 and 15 mmHg. Plasmapheresis was performed by withdrawing 10% of blood volume twice. 2. Both RARs (n = 11) and SARs (n = 5) responded to pulmonary venous congestion by increasing their activities. The responses of the former were proportionately greater. 3. After plasmapheresis which reduced the concentration of plasma proteins by 12.3 +/- 1.0%, the responses of the RARs to pulmonary venous congestion were enhanced significantly. There was no significant change in the responses of SARs. 4. In another set of six RARs, the effects of graded pulmonary venous congestion were investigated twice with an interval of 45 min between the two observations. No significant differences were noted between the two responses. 5. Collection of lymph from the tracheobronchial lymph duct (n = 6) showed that after plasmapheresis, there was an increase in the control lymph flow. In addition, the lymph flow was enhanced during pulmonary venous congestion (mean left atrial pressure increased by 10 mmHg). 6. It is suggested that a natural stimulus for the excitation of the RAR is a function of the fluid fluxes in the pulmonary extravascular space. PMID:2607464

Elephantiasis Nostras Verrucosa (ENV): a complication of congestive heart failure and obesity.

PubMed

Baird, Drew; Bode, David; Akers, Troy; Deyoung, Zachariah

2010-01-01

Congestive heart failure (CHF) and obesity are common medical conditions that have many complications and an increasing incidence in the United States. Presented here is a case of a disfiguring skin condition that visually highlights the dermatologic consequences of poorly controlled CHF and obesity. This condition will probably become more common as CHF and obesity increase in the US.

Simulation Research Framework with Embedded Intelligent Algorithms for Analysis of Multi-Target, Multi-Sensor, High-Cluttered Environments

NASA Astrophysics Data System (ADS)

Hanlon, Nicholas P.

The National Air Space (NAS) can be easily described as a complex aviation system-of-systems that seamlessly works in harmony to provide safe transit for all aircraft within its domain. The number of aircraft within the NAS is growing and according the FAA, "[o]n any given day, more than 85,000 flights are in the skies in the United States...This translates into roughly 5,000 planes in the skies above the United States at any given moment. More than 15,000 federal air traffic controllers in airport traffic control towers, terminal radar approach control facilities and air route traffic control centers guide pilots through the system". The FAA is currently rolling out the Next Generation Air Transportation System (NextGen) to handle projected growth while leveraging satellite-based navigation for improved tracking. A key component to instantiating NextGen lies in the equipage of Automatic Dependent Surveillance-Broadcast (ADS-B), a performance based surveillance technology that uses GPS navigation for more precise positioning than radars providing increased situational awareness to air traffic controllers. Furthermore, the FAA is integrating UAS into the NAS, further congesting the airways and information load on air traffic controllers. The expected increase in aircraft density due to NextGen implementation and UAS integration will require innovative algorithms to cope with the increase data flow and to support air traffic controllers in their decision-making. This research presents a few innovative algorithms to support increased aircraft density and UAS integration into the NAS. First, it is imperative that individual tracks are correlated prior to fusing to ensure a proper picture of the environment is correct. However, current approaches do not scale well as the number of targets and sensors are increased. This work presents a fuzzy clustering design to hierarchically break the problem down into smaller subspaces prior to correlation. This approach provides nearly identical performance metrics at orders of magnitude faster in execution. Second, a fuzzy inference system is presented that alleviates air traffic controllers from information overload by utilizing flight plan data and radar/GPS correlation values to highlight aircraft that deviate from their intended routes. Third, a genetic algorithm optimizes sensor placement that is robust and capable of handling unexpected routes in the environment. Fourth, a fuzzy CUSUM algorithm more accurately detects and corrects aircraft mode changes. Finally, all the work is packaged in a holistic simulation research framework that provides evaluation and analysis of various multi-sensor, multi-target scenarios.

High performance interconnection between high data rate networks

NASA Technical Reports Server (NTRS)

Foudriat, E. C.; Maly, K.; Overstreet, C. M.; Zhang, L.; Sun, W.

1992-01-01

The bridge/gateway system needed to interconnect a wide range of computer networks to support a wide range of user quality-of-service requirements is discussed. The bridge/gateway must handle a wide range of message types including synchronous and asynchronous traffic, large, bursty messages, short, self-contained messages, time critical messages, etc. It is shown that messages can be classified into three basic classes, synchronous and large and small asynchronous messages. The first two require call setup so that packet identification, buffer handling, etc. can be supported in the bridge/gateway. Identification enables resequences in packet size. The third class is for messages which do not require call setup. Resequencing hardware based to handle two types of resequencing problems is presented. The first is for a virtual parallel circuit which can scramble channel bytes. The second system is effective in handling both synchronous and asynchronous traffic between networks with highly differing packet sizes and data rates. The two other major needs for the bridge/gateway are congestion and error control. A dynamic, lossless congestion control scheme which can easily support effective error correction is presented. Results indicate that the congestion control scheme provides close to optimal capacity under congested conditions. Under conditions where error may develop due to intervening networks which are not lossless, intermediate error recovery and correction takes 1/3 less time than equivalent end-to-end error correction under similar conditions.

Reducing Traffic Congestions by Introducing CACC-Vehicles on a Multi-Lane Highway Using Agent-Based Approach

NASA Technical Reports Server (NTRS)

Arnaout, Georges M.; Bowling, Shannon R.

2011-01-01

Traffic congestion is an ongoing problem of great interest to researchers from different areas in academia. With the emerging technology for inter-vehicle communication, vehicles have the ability to exchange information with predecessors by wireless communication. In this paper, we present an agent-based model of traffic congestion and examine the impact of having CACC (Cooperative Adaptive Cruise Control) embedded vehicle(s) on a highway system consisting of 4 traffic lanes without overtaking. In our model, CACC vehicles adapt their acceleration/deceleration according to vehicle-to-vehicle inter-communication. We analyze the average speed of the cars, the shockwaves, and the evolution of traffic congestion throughout the lifecycle of the model. The study identifies how CACC vehicles affect the dynamics of traffic flow on a complex network and reduce the oscillatory behavior (stop and go) resulting from the acceleration/deceleration of the vehicles.

Preliminary studies on nasal decongestant activity from the seed of the shea butter tree, Butyrospermum parkii.

PubMed

Tella, A

1979-05-01

1 The seed of Butyrospermum parkii yields shea butter which according to local traditional healers relieves inflammation of the nostrils. 2 Since there is as yet no absolutely satisfactory nasal decongestant in clinical use, it was decided to investigate the effects of shea butter in nasal congestion. The substance was prepared in the laboratory. 3 The human subjects used were those suffering from rhinitis with moderate to severe nasal congestion. They were divided into the test group which received shea butter, the control group which was treated with xylometazoline and the 'placebo' group which received white petroleum jelly B.P. 4 The results showed that nasal congestion was relieved more satisfactorily in the test group than in the other two groups. 5 It is concluded that shea butter may prove more efficacious in nasal congestion than conventional nasal drops.

Preliminary studies on nasal decongestant activity from the seed of the shea butter tree, Butyrospermum parkii.

PubMed Central

Tella, A

1979-01-01

1 The seed of Butyrospermum parkii yields shea butter which according to local traditional healers relieves inflammation of the nostrils. 2 Since there is as yet no absolutely satisfactory nasal decongestant in clinical use, it was decided to investigate the effects of shea butter in nasal congestion. The substance was prepared in the laboratory. 3 The human subjects used were those suffering from rhinitis with moderate to severe nasal congestion. They were divided into the test group which received shea butter, the control group which was treated with xylometazoline and the 'placebo' group which received white petroleum jelly B.P. 4 The results showed that nasal congestion was relieved more satisfactorily in the test group than in the other two groups. 5 It is concluded that shea butter may prove more efficacious in nasal congestion than conventional nasal drops. PMID:89854

Influence of TCSC Devices on Congestion Management in a Deregulated Power System Using Evolutionary Programming Technique

NASA Astrophysics Data System (ADS)

Ananthichristy, A., Dr.; Elanthirayan, R.; Brindha, R., Dr.; Siddhiq, M. S.; Venkatesh, N.; Harshit, M. V.; Nikhilreddy, M.

2018-04-01

Congestion management is one of the technical challenges in power system deregulation. In deregulated electricity market it may always not be possible to dispatch all of the contracted power transactions due to congestion of the transmission corridors. Transmission congestion occurs when there is insufficient transmission capacity to simultaneously accommodate all constraints for transmission of a line. Flexible Alternative Current Transmission System (FACTS) devices can be an alternative to reduce the flows in the heavily loaded lines, resulting in an increased loadability, low system loss, improved stability of the network, reduced cost of production and fulfilled contractual requirement by controlling the power flow in the network. A method to determine the optimal location of FACTS has been suggested based on reduction of total system VAR power losses. The simulation was done on IEEE 14 bus system and results were obtained.

A simulation-based study of HighSpeed TCP and its deployment

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

Souza, Evandro de

2003-05-01

The current congestion control mechanism used in TCP has difficulty reaching full utilization on high speed links, particularly on wide-area connections. For example, the packet drop rate needed to fill a Gigabit pipe using the present TCP protocol is below the currently achievable fiber optic error rates. HighSpeed TCP was recently proposed as a modification of TCP's congestion control mechanism to allow it to achieve reasonable performance in high speed wide-area links. In this research, simulation results showing the performance of HighSpeed TCP and the impact of its use on the present implementation of TCP are presented. Network conditions includingmore » different degrees of congestion, different levels of loss rate, different degrees of bursty traffic and two distinct router queue management policies were simulated. The performance and fairness of HighSpeed TCP were compared to the existing TCP and solutions for bulk-data transfer using parallel streams.« less

Making the Traffic Operations Case for Congestion Pricing: Operational Impacts of Congestion Pricing

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

Chin, Shih-Miao; Hu, Patricia S; Davidson, Diane

2011-02-01

Congestion begins when an excess of vehicles on a segment of roadway at a given time, resulting in speeds that are significantly slower than normal or 'free flow' speeds. Congestion often means stop-and-go traffic. The transition occurs when vehicle density (the number of vehicles per mile in a lane) exceeds a critical level. Once traffic enters a state of congestion, recovery or time to return to a free-flow state is lengthy; and during the recovery process, delay continues to accumulate. The breakdown in speed and flow greatly impedes the efficient operation of the freeway system, resulting in economic, mobility, environmentalmore » and safety problems. Freeways are designed to function as access-controlled highways characterized by uninterrupted traffic flow so references to freeway performance relate primarily to the quality of traffic flow or traffic conditions as experienced by users of the freeway. The maximum flow or capacity of a freeway segment is reached while traffic is moving freely. As a result, freeways are most productive when they carry capacity flows at 60 mph, whereas lower speeds impose freeway delay, resulting in bottlenecks. Bottlenecks may be caused by physical disruptions, such as a reduced number of lanes, a change in grade, or an on-ramp with a short merge lane. This type of bottleneck occurs on a predictable or 'recurrent' basis at the same time of day and same day of week. Recurrent congestion totals 45% of congestion and is primarily from bottlenecks (40%) as well as inadequate signal timing (5%). Nonrecurring bottlenecks result from crashes, work zone disruptions, adverse weather conditions, and special events that create surges in demand and that account for over 55% of experienced congestion. Figure 1.1 shows that nonrecurring congestion is composed of traffic incidents (25%), severe weather (15%), work zones, (10%), and special events (5%). Between 1995 and 2005, the average percentage change in increased peak traveler delay, based on hours spent in traffic in a year, grew by 22% as the national average of hours spent in delay grew from 36 hours to 44 hours. Peak delay per traveler grew one-third in medium-size urban areas over the 10 year period. The traffic engineering community has developed an arsenal of integrated tools to mitigate the impacts of congestion on freeway throughput and performance, including pricing of capacity to manage demand for travel. Congestion pricing is a strategy which dynamically matches demand with available capacity. A congestion price is a user fee equal to the added cost imposed on other travelers as a result of the last traveler's entry into the highway network. The concept is based on the idea that motorists should pay for the additional congestion they create when entering a congested road. The concept calls for fees to vary according to the level of congestion with the price mechanism applied to make travelers more fully aware of the congestion externality they impose on other travelers and the system itself. The operational rationales for the institution of pricing strategies are to improve the efficiency of operations in a corridor and/or to better manage congestion. To this end, the objectives of this project were to: (1) Better understand and quantify the impacts of congestion pricing strategies on traffic operations through the study of actual projects, and (2) Better understand and quantify the impacts of congestion pricing strategies on traffic operations through the use of modeling and other analytical methods. Specifically, the project was to identify credible analytical procedures that FHWA can use to quantify the impacts of various congestion pricing strategies on traffic flow (throughput) and congestion.« less

Feasibility of a special-purpose computer to solve the Navier-Stokes equations

NASA Technical Reports Server (NTRS)

Gritton, E. C.; King, W. S.; Sutherland, I.; Gaines, R. S.; Gazley, C., Jr.; Grosch, C.; Juncosa, M.; Petersen, H.

1978-01-01

Orders-of-magnitude improvements in computer performance can be realized with a parallel array of thousands of fast microprocessors. In this architecture, wiring congestion is minimized by limiting processor communication to nearest neighbors. When certain standard algorithms are applied to a viscous flow problem and existing LSI technology is used, performance estimates of this conceptual design show a dramatic decrease in computational time when compared to the CDC 7600.

Adverse events with intravitreal injection of vascular endothelial growth factor inhibitors: nested case-control study

PubMed Central

Gill, Sudeep S; Bronskill, Susan E; Paterson, J Michael; Whitehead, Marlo

2012-01-01

Objective To assess the risk of systemic adverse events associated with intravitreal injections of vascular endothelial growth factor inhibiting drugs. Design Population based nested case-control study. Setting Ontario, Canada. Participants 91 378 older adults with a history of physician diagnosed retinal disease identified between 1 April 2006 and 31 March 2011. Cases were 1477 patients admitted to hospital for ischaemic stroke, 2229 admitted for an acute myocardial infarction, 1059 admitted or assessed in an emergency department for venous thromboembolism, and 2623 admitted for congestive heart failure. Event-free controls (at a ratio of 5:1) were matched to cases on the basis of year of birth, sex, history of the outcome in the previous 5 years, and diabetes. Main exposure measure Exposure to vascular endothelial growth factor inhibiting drugs identified within 180 days before the index date. Results After adjustment for potential confounders, participants who had ischaemic stroke, acute myocardial infarction, congestive heart failure, or venous thromboembolism were not more likely than control participants to have been exposed to either bevacizumab (adjusted odds ratios of 0.95 (95% confidence interval 0.68 to 1.34) for ischaemic stroke, 1.04 (0.77 to 1.39) for acute myocardial infarction, 0.81 (0.49 to 1.34) for venous thromboembolism, and 1.21 (0.91 to 1.62) for congestive heart failure) or ranibizumab (adjusted odds ratios 0.87 (0.68 to 1.10) for ischaemic stroke, 0.90 (0.72 to 1.11) for acute myocardial infarction, 0.88 (0.67 to 1.16) for venous thromboembolism, and 0.87 (0.70 to 1.07) for congestive heart failure). Similarly, a secondary analysis of exclusive users of bevacizumab or ranibizumab showed no differences in risk between the two drugs (adjusted odds ratios for bevacizumab relative to ranibizumab of 1.03 (0.67 to 1.60) for ischaemic stroke, 1.23 (0.85 to 1.77) for acute myocardial infarction, 0.92 (0.51 to 1.69) for venous thromboembolism, and 1.35 (0.93 to 1.95) for congestive heart failure). These findings were consistent for all but one outcome in subgroup analyses. Conclusions Intravitreal injections of bevacizumab and ranibizumab were not associated with significant risks of ischaemic stroke, acute myocardial infarction, congestive heart failure, or venous thromboembolism. PMID:22763393

Energy consumption and control response evaluations of AODV routing in WSANs for building-temperature control.

PubMed

Booranawong, Apidet; Teerapabkajorndet, Wiklom; Limsakul, Chusak

2013-06-27

The main objective of this paper is to investigate the effects of routing protocols on wireless sensor and actuator networks (WSANs), focusing on the control system response and the energy consumption of nodes in a network. We demonstrate that routing algorithms designed without considering the relationship between communication and control cannot be appropriately used in wireless networked control applications. For this purpose, an ad-hoc on-demand distance vector (AODV) routing, an IEEE 802.15.4, and a building-temperature control system are employed for this exploration. The findings from our scenarios show that the AODV routing can select a path with a high traffic load for data transmission. It takes a long time before deciding to change a new route although it experiences the unsuccessful transmission of packets. As a result, the desirable control target cannot be achieved in time, and nodes consume more energy due to frequent packet collisions and retransmissions. Consequently, we propose a simple routing solution to alleviate these research problems by modifying the original AODV routing protocol. The delay-threshold is considered to avoid any congested connection during routing procedures. The simulation results demonstrate that our solution can be appropriately applied in WSANs. Both the energy consumption and the control system response are improved.

Topical nasal decongestant oxymetazoline (0.05%) provides relief of nasal symptoms for 12 hours.

PubMed

Druce, H M; Ramsey, D L; Karnati, S; Carr, A N

2018-05-22

Nasal congestion, often referred to as stuffy nose or blocked nose is one of the most prevalent and bothersome symptoms of an upper respiratory tract infection. Oxymetazoline, a widely used intranasal decongestant, offers fast symptom relief, but little is known about the duration of effect. The results of 2 randomized, double-blind, vehicle-controlled, single-dose, parallel, clinical studies (Study 1, n=67; Study 2, n=61) in which the efficacy of an oxymetazoline (0.05% Oxy) nasal spray in patients with acute coryzal rhinitis was assessed over a 12-hour time-period. Data were collected on both subjective relief of nasal congestion (6-point nasal congestion scale) and objective measures of nasal patency (anterior rhinomanometry) in both studies. A pooled study analysis showed statistically significant changes from baseline in subjective nasal congestion for 0.05% oxymetazoline and vehicle at each hourly time-point from Hour 1 through Hour 12 (marginally significant at Hour 11). An objective measure of nasal flow was statistically significant at each time-point up to 12 hours. Adverse events on either treatment were infrequent. The number of subjects who achieved an improvement in subjective nasal congestion scores of at least 1.0 was significantly higher in the Oxy group vs. vehicle at all hourly time-points on a 6-point nasal congestion scale. This study shows for the first time, that oxymetazoline provides both statistically significant and clinically meaningful relief of nasal congestion and improves nasal airflow for up to 12 hours following a single dose.

Traffic control at crossroad that cut railroad based on friendly environment: Case : Crossroads at Prof. M. Yamin road with Gaharu road in Medan

NASA Astrophysics Data System (ADS)

Hutauruk, Sindak

2017-09-01

The frequent congestion causes accumulation of vehicles at the intersection of roads cutting off railroads, reducing the functionality of highway services, the loss of vehicle functions as a means of transportation, waste of fuel energy, and CO2 increase in intersections. The occurrence of congestion caused by the absence of integration of traffic light controls by opening and closing the railway barrier, therefore need to be done integrated control especially during and after a while train crossing the highway. The case raised in this study is the crossroads Prof. H.M. Jalan Yamin with Gaharu road in Medan. Researchers tried to solve the problem by designing and creating a tool that would coordinate and regulate traffic lights with railroad doors, thus reducing congestion for 23 minutes, reducing fuel by as much as 60,340 liters per day, thereby reducing CO2 exhaust gases in the area. This tool uses microcontroller as its control center. This design is done with a miniature simulation, meaning it is not done in the actual situation, but the field conditions can be represented in the simulation in the form of miniature.

Congestion control for a fair packet delivery in WSN: from a complex system perspective.

PubMed

Aguirre-Guerrero, Daniela; Marcelín-Jiménez, Ricardo; Rodriguez-Colina, Enrique; Pascoe-Chalke, Michael

2014-01-01

In this work, we propose that packets travelling across a wireless sensor network (WSN) can be seen as the active agents that make up a complex system, just like a bird flock or a fish school, for instance. From this perspective, the tools and models that have been developed to study this kind of systems have been applied. This is in order to create a distributed congestion control based on a set of simple rules programmed at the nodes of the WSN. Our results show that it is possible to adapt the carried traffic to the network capacity, even under stressing conditions. Also, the network performance shows a smooth degradation when the traffic goes beyond a threshold which is settled by the proposed self-organized control. In contrast, without any control, the network collapses before this threshold. The use of the proposed solution provides an effective strategy to address some of the common problems found in WSN deployment by providing a fair packet delivery. In addition, the network congestion is mitigated using adaptive traffic mechanisms based on a satisfaction parameter assessed by each packet which has impact on the global satisfaction of the traffic carried by the WSN.

TinyOS-based quality of service management in wireless sensor networks

USGS Publications Warehouse

Peterson, N.; Anusuya-Rangappa, L.; Shirazi, B.A.; Huang, R.; Song, W.-Z.; Miceli, M.; McBride, D.; Hurson, A.; LaHusen, R.

2009-01-01

Previously the cost and extremely limited capabilities of sensors prohibited Quality of Service (QoS) implementations in wireless sensor networks. With advances in technology, sensors are becoming significantly less expensive and the increases in computational and storage capabilities are opening the door for new, sophisticated algorithms to be implemented. Newer sensor network applications require higher data rates with more stringent priority requirements. We introduce a dynamic scheduling algorithm to improve bandwidth for high priority data in sensor networks, called Tiny-DWFQ. Our Tiny-Dynamic Weighted Fair Queuing scheduling algorithm allows for dynamic QoS for prioritized communications by continually adjusting the treatment of communication packages according to their priorities and the current level of network congestion. For performance evaluation, we tested Tiny-DWFQ, Tiny-WFQ (traditional WFQ algorithm implemented in TinyOS), and FIFO queues on an Imote2-based wireless sensor network and report their throughput and packet loss. Our results show that Tiny-DWFQ performs better in all test cases. ?? 2009 IEEE.

MQCC: Maximum Queue Congestion Control for Multipath Networks with Blockage

DTIC Science & Technology

2015-10-19

higher error rates in wireless networks result in a great deal of “false” congestion indications, resulting in underutilization of the network [4...approaches that are relevant to lossy wireless networks . Multipath TCP (MPTCP) schemes [9], [10] explore the design and implementation of multipath...attempts to “fix” TCP to work with lossy wireless networks using existing techniques. The authors have taken the view that because packet losses are

User Access Management Based on Network Pricing for Social Network Applications

PubMed Central

Ma, Xingmin; Gu, Qing

2018-01-01

Social applications play a very important role in people’s lives, as users communicate with each other through social networks on a daily basis. This presents a challenge: How does one receive high-quality service from social networks at a low cost? Users can access different kinds of wireless networks from various locations. This paper proposes a user access management strategy based on network pricing such that networks can increase its income and improve service quality. Firstly, network price is treated as an optimizing access parameter, and an unascertained membership algorithm is used to make pricing decisions. Secondly, network price is adjusted dynamically in real time according to network load. Finally, selecting a network is managed and controlled in terms of the market economy. Simulation results show that the proposed scheme can effectively balance network load, reduce network congestion, improve the user's quality of service (QoS) requirements, and increase the network’s income. PMID:29495252

Excluding infection through procalcitonin testing improves outcomes of congestive heart failure patients presenting with acute respiratory symptoms: results from the randomized ProHOSP trial.

PubMed

Schuetz, Philipp; Kutz, Alexander; Grolimund, Eva; Haubitz, Sebastian; Demann, Désirée; Vögeli, Alaadin; Hitz, Fabienne; Christ-Crain, Mirjam; Thomann, Robert; Falconnier, Claudine; Hoess, Claus; Henzen, Christoph; Marlowe, Robert J; Zimmerli, Werner; Mueller, Beat

2014-08-20

We sought to determine whether exclusion of infection and antibiotic stewardship with the infection biomarker procalcitonin improves outcomes in congestive heart failure (CHF) patients presenting to emergency departments with respiratory symptoms and suspicion of respiratory infection. We performed a secondary analysis of patients with a past medical history of CHF formerly included in a Swiss multicenter randomized-controlled trial. The trial compared antibiotic stewardship according to a procalcitonin algorithm or state-of-the-art guidelines (controls). The primary endpoint was a 30-day adverse outcome (death, intensive care unit admission); the secondary endpoints included a 30-day antibiotic exposure. In the 110/233 analyzed patients (47.2%) with low initial procalcitonin (<0.25 μg/L), suggesting the absence of systemic bacterial infection, those randomized to procalcitonin guidance (n=50) had a significantly lower adverse outcome rate compared to controls (n=60): 4% vs. 20% (absolute difference -16.0%, 95% confidence interval (CI) -28.4% to -3.6%, P=0.01), and significantly reduced antibiotic exposure [days] (mean 3.7 ± 4.0 vs. 6.5 ± 4.4, difference -2.8 [95% CI, -4.4 to -1.2], P<0.01). When initial procalcitonin was ≥0.25 μg/L, procalcitonin-guided patients had significantly reduced antibiotic exposure due to early stop of therapy without any difference in adverse outcomes (25.8% vs. 24.6%, difference [95% CI] 1.2% [-14.5% to 16.9%, P=0.88]). CHF patients presenting to the emergency department with respiratory symptoms and suspicion for respiratory infection had decreased antibiotic exposure and improved outcomes when procalcitonin measurement was used to exclude bacterial infection and guide antibiotic treatment. These data provide further evidence for the potential harmful effects of antibiotic / fluid treatment when used instead of diuretics and heart failure medication in clinically symptomatic CHF patients without underlying infection. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Critical behaviour in charging of electric vehicles

NASA Astrophysics Data System (ADS)

Carvalho, Rui; Buzna, Lubos; Gibbens, Richard; Kelly, Frank

2015-09-01

The increasing penetration of electric vehicles over the coming decades, taken together with the high cost to upgrade local distribution networks and consumer demand for home charging, suggest that managing congestion on low voltage networks will be a crucial component of the electric vehicle revolution and the move away from fossil fuels in transportation. Here, we model the max-flow and proportional fairness protocols for the control of congestion caused by a fleet of vehicles charging on two real-world distribution networks. We show that the system undergoes a continuous phase transition to a congested state as a function of the rate of vehicles plugging to the network to charge. We focus on the order parameter and its fluctuations close to the phase transition, and show that the critical point depends on the choice of congestion protocol. Finally, we analyse the inequality in the charging times as the vehicle arrival rate increases, and show that charging times are considerably more equitable in proportional fairness than in max-flow.

Iodine-123 metaiodobenzylguanidine imaging of the heart in idiopathic congestive cardiomyopathy and cardiac transplants

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

Glowniak, J.V.; Turner, F.E.; Gray, L.L.

1989-07-01

Iodine-123 metaiodobenzylguanidine ((/sup 123/I)MIBG) is a norepinephrine analog which can be used to image the sympathetic innervation of the heart. In this study, cardiac imaging with (/sup 123/I)MIBG was performed in patients with idiopathic congestive cardiomyopathy and compared to normal controls. Initial uptake, half-time of tracer within the heart, and heart to lung ratios were all significantly reduced in patients compared to normals. Uptake in lungs, liver, salivary glands, and spleen was similar in controls and patients with cardiomyopathy indicating that decreased MIBG uptake was not a generalized abnormality in these patients. Iodine-123 MIBG imaging was also performed in cardiacmore » transplant patients to determine cardiac nonneuronal uptake. Uptake in transplants was less than 10% of normals in the first 2 hr and nearly undetectable after 16 hr. The decreased uptake of MIBG suggests cardiac sympathetic nerve dysfunction while the rapid washout of MIBG from the heart suggests increased cardiac sympathetic nerve activity in idiopathic congestive cardiomyopathy.« less

Impact of traffic oscillations on freeway crash occurrences.

PubMed

Zheng, Zuduo; Ahn, Soyoung; Monsere, Christopher M

2010-03-01

Traffic oscillations are typical features of congested traffic flow that are characterized by recurring decelerations followed by accelerations (stop-and-go driving). The negative environmental impacts of these oscillations are widely accepted, but their impact on traffic safety has been debated. This paper describes the impact of freeway traffic oscillations on traffic safety. This study employs a matched case-control design using high-resolution traffic and crash data from a freeway segment. Traffic conditions prior to each crash were taken as cases, while traffic conditions during the same periods on days without crashes were taken as controls. These were also matched by presence of congestion, geometry and weather. A total of 82 cases and about 80,000 candidate controls were extracted from more than three years of data from 2004 to 2007. Conditional logistic regression models were developed based on the case-control samples. To verify consistency in the results, 20 different sets of controls were randomly extracted from the candidate pool for varying control-case ratios. The results reveal that the standard deviation of speed (thus, oscillations) is a significant variable, with an average odds ratio of about 1.08. This implies that the likelihood of a (rear-end) crash increases by about 8% with an additional unit increase in the standard deviation of speed. The average traffic states prior to crashes were less significant than the speed variations in congestion. Published by Elsevier Ltd.

Does nasal congestion have a role in decreased resistance to regular CPAP usage?

PubMed

İriz, Ayşe; Düzlü, Mehmet; Köktürk, Oğuz; Kemaloğlu, Yusuf Kemal; Eravcı, Fakih Cihat; Zorlu, Mehmet Ekrem; Karamert, Recep

2017-11-01

Nasal obstruction is known to cause resistance to continuous positive airway pressure (CPAP) therapy in obstructive sleep apnea syndrome (OSAS). In this paper, short- and long-term nasal congestion in OSAS patients receiving CPAP treatment were evaluated with acoustic rhinometry (AR). A total of 36 patients with moderate-to-severe OSAS, diagnosed with polysomnography were included in the study. Ten healthy subjects without OSAS constituted the control group. Pre-treatment nasal patency were measured with AR in all participants. 26 patients used the recommended CPAP treatment. Ten patients did not accept CPAP treatment. The AR test was repeated for all the subjects after 1 and 3 months except the 3rd month's measurements of the control group. There was no statistically significant difference between the initial minimum cross-sectional area (MCA) measurements of OSAS patients, using or not using CPAP, and the control group (P > 0.05). However, the first month MCA measurements of patients receiving CPAP were found to be significantly decreased compared with the initial values (P < 0.001). There was no significant change in the first and third months MCA values in the control group and patients who did not use CPAP (P > 0.05). No significant difference revealed in the 3rd month MCA measurements of the patients using CPAP compared with the initial values (P > 0.05). In this study, the increased nasal congestion, which is thought to be the cause of CPAP resistance, was objectively demonstrated in OSAS patients using CPAP. In addition, the nasal congestion developing at the first month was shown to disappear over time, supporting the opinion that patient compliance in CPAP treatment is expected to increase after regular device usage.

Stochastic user equilibrium model with a tradable credit scheme and application in maximizing network reserve capacity

NASA Astrophysics Data System (ADS)

Han, Fei; Cheng, Lin

2017-04-01

The tradable credit scheme (TCS) outperforms congestion pricing in terms of social equity and revenue neutrality, apart from the same perfect performance on congestion mitigation. This article investigates the effectiveness and efficiency of TCS on enhancing transportation network capacity in a stochastic user equilibrium (SUE) modelling framework. First, the SUE and credit market equilibrium conditions are presented; then an equivalent general SUE model with TCS is established by virtue of two constructed functions, which can be further simplified under a specific probability distribution. To enhance the network capacity by utilizing TCS, a bi-level mathematical programming model is established for the optimal TCS design problem, with the upper level optimization objective maximizing network reserve capacity and lower level being the proposed SUE model. The heuristic sensitivity analysis-based algorithm is developed to solve the bi-level model. Three numerical examples are provided to illustrate the improvement effect of TCS on the network in different scenarios.

Frequency characteristics of the heart rate variability produced by Cheyne-Stokes respiration during 24-hr ambulatory electrocardiographic monitoring.

PubMed

Ichimaru, Y; Yanaga, T

1989-06-01

Spectral analysis of heart rates during 24-hr ambulatory electrocardiographic monitoring has been carried out to characterize the heart rate spectral components of Cheyne-Stokes respiration (CSR) by using fast Fourier transformation (FFT). Eight patients with congestive heart failure were selected for the study. FFT analyses have been performed for 614.4 sec. Out of the power spectrum, five parameters were extracted to characterize the CSR. The low peak frequencies in eight subjects were between 0.0179 Hz (56 sec) and 0.0081 Hz (123 sec). The algorithms used to detect CSR are the followings: (i) if the LFPA/ULFA ratios were above the absolute value of 1.0, and (ii) the LFPP/MLFP ratios were above the absolute values of 4.0, then the power spectrum is suggestive of CSR. We conclude that the automatic detection of CSR by heart rate spectral analysis during ambulatory ECG monitoring may afford a tool for the evaluation of the patients with congestive heart failure.

Curbing gridlock: Peak-period fees to relieve traffic congestion. Volume 2. Commissioned papers. Special report

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

Not Available

1994-01-01

;Contents: Volume 2: Commissioned Papers: Congestion Trends in Metropolitan Areas; Alternative Methods for Measuring Congestion Levels; Potential of Congestion Pricing in the Metropolitan Washington Region; Transportation Pricing and Travel Behavior; Peak Pricing Strategies in Transportation, Utilities, and Telecommunications: Lessons for Road Pricing; Cashing Out Employer-Paid Parking: A Precedent for Congestion Pricing; The New York Region: First in Tolls, Last in Road Pricing; Pricing Urban Roadways: Administrative and Institutional Issues; Equity and Fairness Considerations of Congestion Pricing; The Politics of Congestion Pricing; Institutional and Political Challenges in Implementing Congestion Pricing: Case Study of the San Francisco Bay Area; How Congestion Pricingmore » Came to Be Proposed in the San Diego Region: A Case History; Urban Transportation Congestion Pricing: Effects on Urban Form; Congestion Pricing and Motor Vehicle Emissions: An Initial Review; Private Toll Roads: Acceptability of Congestion Pricing in Southern California; Potential of Next-Generation Technology; Electronic Toll Collection Systems; and Impacts of Congestion Pricing on Transit and Carpool Demand and Supply.« less

Traffic congestion and reliability : trends and advanced strategies for congestion mitigation.

DOT National Transportation Integrated Search

2005-09-01

The report Traffic Congestion and Reliability: Trends and Advanced Strategies for : Congestion Mitigation provides a snapshot of congestion in the United States by : summarizing recent trends in congestion, highlighting the role of travel time : reli...

SDTCP: Towards Datacenter TCP Congestion Control with SDN for IoT Applications.

PubMed

Lu, Yifei; Ling, Zhen; Zhu, Shuhong; Tang, Ling

2017-01-08

The Internet of Things (IoT) has gained popularity in recent years. Today's IoT applications are now increasingly deployed in cloud platforms to perform Big Data analytics. In cloud data center networks (DCN), TCP incast usually happens when multiple senders simultaneously communicate with a single receiver. However, when TCP incast happens, DCN may suffer from both throughput collapse for TCP burst flows and temporary starvation for TCP background flows. In this paper, we propose a software defined network (SDN)-based TCP congestion control mechanism, referred to as SDTCP, to leverage the features, e.g., centralized control methods and the global view of the network, in order to solve the TCP incast problems. When we detect network congestion on an OpenFlow switch, our controller can select the background flows and reduce their bandwidth by adjusting the advertised window of TCP ACK packets of the corresponding background flows so as to reserve more bandwidth for burst flows. SDTCP is transparent to the end systems and can accurately decelerate the rate of background flows by leveraging the global view of the network gained via SDN. The experiments demonstrate that our SDTCP can provide high tolerance for burst flows and achieve better flow completion time for short flows. Therefore, SDTCP is an effective and scalable solution for the TCP incast problem.

A placebo-controlled study of the nasal decongestant effect of phenylephrine and pseudoephedrine in the Vienna Challenge Chamber.

PubMed

Horak, Friedrich; Zieglmayer, Petra; Zieglmayer, René; Lemell, Patrick; Yao, Ruji; Staudinger, Heribert; Danzig, Melvyn

2009-02-01

Studies on the efficacy of phenylephrine in the treatment of nasal congestion have yielded inconsistent results, notwithstanding its approval for this indication. To evaluate and compare the decongestant effect of a single dose of phenylephrine to placebo and pseudoephedrine in patients with seasonal allergic rhinitis. This randomized, placebo-controlled, 3-way crossover study evaluated patient-scored nasal congestion, peak nasal inspiratory flow, and rhinomanometry at more than 6 hours in 39 grass-sensitive patients exposed to grass pollen in the Vienna Challenge Chamber. Patients were dosed with immediate-release formulations of phenylephrine, 12 mg, pseudoephedrine, 60 mg, as a control, or placebo. Phenylephrine was not significantly different from placebo in the primary end point, mean change in nasal congestion score at more than 6 hours (P = .56), whereas pseudoephedrine was significantly more effective than both placebo (P < .01) and phenylephrine (P = .01). Phase 1 results showed a difference between phenylephrine and placebo that was 64% of the difference between pseudoephedrine and placebo, substantially greater than the 17% difference observed for all phases. Carryover bias due to patient recall of the pseudoephedrine effect may have influenced these results. Rhinomanometry and peak nasal inspiratory flow results were consistent with these data. Neither phenylephrine nor pseudoephedrine had an effect on the nonnasal symptoms. No adverse events were reported in this study. During a 6-hour observation period, a single dose of pseudoephedrine but not phenylephrine resulted in significant improvement in measures of nasal congestion. Neither phenylephrine nor pseudoephedrine had an effect on nonnasal symptoms.

Real-Time Smart Grids Control for Preventing Cascading Failures and Blackout using Neural Networks: Experimental Approach for N-1-1 Contingency

NASA Astrophysics Data System (ADS)

Zarrabian, Sina; Belkacemi, Rabie; Babalola, Adeniyi A.

2016-12-01

In this paper, a novel intelligent control is proposed based on Artificial Neural Networks (ANN) to mitigate cascading failure (CF) and prevent blackout in smart grid systems after N-1-1 contingency condition in real-time. The fundamental contribution of this research is to deploy the machine learning concept for preventing blackout at early stages of its occurrence and to make smart grids more resilient, reliable, and robust. The proposed method provides the best action selection strategy for adaptive adjustment of generators' output power through frequency control. This method is able to relieve congestion of transmission lines and prevent consecutive transmission line outage after N-1-1 contingency condition. The proposed ANN-based control approach is tested on an experimental 100 kW test system developed by the authors to test intelligent systems. Additionally, the proposed approach is validated on the large-scale IEEE 118-bus power system by simulation studies. Experimental results show that the ANN approach is very promising and provides accurate and robust control by preventing blackout. The technique is compared to a heuristic multi-agent system (MAS) approach based on communication interchanges. The ANN approach showed more accurate and robust response than the MAS algorithm.

Mean field games with congestion

NASA Astrophysics Data System (ADS)

Achdou, Yves; Porretta, Alessio

2018-03-01

We consider a class of systems of time dependent partial differential equations which arise in mean field type models with congestion. The systems couple a backward viscous Hamilton-Jacobi equation and a forward Kolmogorov equation both posed in $(0,T)\\times (\\mathbb{R}^N /\\mathbb{Z}^N)$. Because of congestion and by contrast with simpler cases, the latter system can never be seen as the optimality conditions of an optimal control problem driven by a partial differential equation. The Hamiltonian vanishes as the density tends to $+\\infty$ and may not even be defined in the regions where the density is zero. After giving a suitable definition of weak solutions, we prove the existence and uniqueness results of the latter under rather general assumptions. No restriction is made on the horizon $T$.

Efficacy and safety of desloratadine/pseudoephedrine combination vs its components in seasonal allergic rhinitis.

PubMed

Grubbe, R E; Lumry, W R; Anolik, R

2009-01-01

Antihistamines are first-line therapy for the treatment of seasonal allergic rhinitis (AR); however, an oral decongestant is often added to improve control of nasal congestion. To examine whether a tablet combining the nonsedating antihistamine desloratadine and the decongestant pseudoephedrine was more effective than either drug administered alone in reducing the symptoms of seasonal AR, including nasal congestion. In this multicenter, double-blind study, participants (N = 598) with symptomatic seasonal AR were administered either a combination tablet of desloratadine 2.5 mg/pseudoephedrine 120 mg (DL/PSE) bid, a desloratadine 5.0 mg qd and a placebo tablet, or pseudoephedrine 120 mg bid. Participants assessed their symptom severity twice daily over the 2-week treatment period. The primary variable to assess the effects of the antihistamine component--mean change from baseline in average AM/PM reflective total symptom score (TSS), excluding nasal congestion--was significantly greater (-6.54) for DL/PSE than for desloratadine (-5.09) or pseudoephedrine (-5.07) monotherapy (P < .001 for both). The primary variable to assess the effects of the decongestant component--mean change from baseline in average AM/PM reflective nasal congestion score--was also significantly greater (-0.93) for DL/PSE than for desloratadine (-0.66) or pseudoephedrine (-0.75) (P < .001 vs desloratadine; P = .006 vs pseudoephedrine). This study demonstrated that DL/PSE therapy was more effective in reducing symptoms of seasonal AR, including nasal congestion, than the individual components when administered alone, thus supporting use of this combination in participants with symptomatic seasonal AR and prominent nasal congestion.

Histological Changes in the Thyroid Gland in Cases of Infant and Early Childhood Asphyxia-A Preliminary Study.

PubMed

Byard, Roger W; Bellis, Maria

2016-05-01

A retrospective blinded study of thyroid gland histology was undertaken in 50 infants and young children aged from 1 to 24 months. Deaths were due to (i) suffocation (N = 7), hanging (4), wedging (3), and chest and/or neck compression (4), and (ii) SIDS (20), noncervical trauma (7), organic disease, (4) and drug toxicity (1). In the asphyxia group (N = 18), thyroid gland congestion ranged from 0 to 3+ with 39% of cases (7/18) having moderate/marked congestion. In three cases, focal aggregates of red blood cells (blood islands) were observed within the intrafollicular colloid. These deaths involved chest compression, chest and/or neck compression, and crush asphyxia in a vehicle accident, and all had facial petechiae. Only 22% of the 32 control cases (7/32) had moderate/marked congestion with no blood islands being identified (p < 0.05). Blood islands within the thyroid gland may be caused by congestion associated with crushing or compression and may provide supportive evidence for this diagnosis. © 2016 American Academy of Forensic Sciences.

Comparing Perceptions and Measures of Congestion

DOT National Transportation Integrated Search

2012-10-01

Peoples perception of congestion and the actual measured congestion do not always agree. Measured : congestion relates to the delay resulting from field measurements of traffic volume, speed, and travel : time. Peoples perception of congestion ...

Mixed Transportation Network Design under a Sustainable Development Perspective

PubMed Central

Qin, Jin; Ni, Ling-lin; Shi, Feng

2013-01-01

A mixed transportation network design problem considering sustainable development was studied in this paper. Based on the discretization of continuous link-grade decision variables, a bilevel programming model was proposed to describe the problem, in which sustainability factors, including vehicle exhaust emissions, land-use scale, link load, and financial budget, are considered. The objective of the model is to minimize the total amount of resources exploited under the premise of meeting all the construction goals. A heuristic algorithm, which combined the simulated annealing and path-based gradient projection algorithm, was developed to solve the model. The numerical example shows that the transportation network optimized with the method above not only significantly alleviates the congestion on the link, but also reduces vehicle exhaust emissions within the network by up to 41.56%. PMID:23476142

Mixed transportation network design under a sustainable development perspective.

PubMed

Qin, Jin; Ni, Ling-lin; Shi, Feng

2013-01-01

A mixed transportation network design problem considering sustainable development was studied in this paper. Based on the discretization of continuous link-grade decision variables, a bilevel programming model was proposed to describe the problem, in which sustainability factors, including vehicle exhaust emissions, land-use scale, link load, and financial budget, are considered. The objective of the model is to minimize the total amount of resources exploited under the premise of meeting all the construction goals. A heuristic algorithm, which combined the simulated annealing and path-based gradient projection algorithm, was developed to solve the model. The numerical example shows that the transportation network optimized with the method above not only significantly alleviates the congestion on the link, but also reduces vehicle exhaust emissions within the network by up to 41.56%.

Prognostic Significance of Creatinine Increases During an Acute Heart Failure Admission in Patients With and Without Residual Congestion: A Post Hoc Analysis of the PROTECT Data.

PubMed

Metra, Marco; Cotter, Gad; Senger, Stefanie; Edwards, Christopher; Cleland, John G; Ponikowski, Piotr; Cursack, Guillermo C; Milo, Olga; Teerlink, John R; Givertz, Michael M; O'Connor, Christopher M; Dittrich, Howard C; Bloomfield, Daniel M; Voors, Adriaan A; Davison, Beth A

2018-05-01

The importance of a serum creatinine increase, traditionally considered worsening renal function (WRF), during admission for acute heart failure has been recently debated, with data suggesting an interaction between congestion and creatinine changes. In post hoc analyses, we analyzed the association of WRF with length of hospital stay, 30-day death or cardiovascular/renal readmission and 90-day mortality in the PROTECT study (Placebo-Controlled Randomized Study of the Selective A1 Adenosine Receptor Antagonist Rolofylline for Patients Hospitalized With Acute Decompensated Heart Failure and Volume Overload to Assess Treatment Effect on Congestion and Renal Function). Daily creatinine changes from baseline were categorized as WRF (an increase of 0.3 mg/dL or more) or not. Daily congestion scores were computed by summing scores for orthopnea, edema, and jugular venous pressure. Of the 2033 total patients randomized, 1537 patients had both available at study day 14. Length of hospital stay was longer and 30-day cardiovascular/renal readmission or death more common in patients with WRF. However, these were driven by significant associations in patients with concomitant congestion at the time of assessment of renal function. The mean difference in length of hospital stay because of WRF was 3.51 (95% confidence interval, 1.29-5.73) more days ( P =0.0019), and the hazard ratio for WRF on 30-day death or heart failure hospitalization was 1.49 (95% confidence interval, 1.06-2.09) times higher ( P =0.0205), in significantly congested than nonsignificantly congested patients. A similar trend was observed with 90-day mortality although not statistically significant. In patients admitted for acute heart failure, WRF defined as a creatinine increase of ≥0.3 mg/dL was associated with longer length of hospital stay, and worse 30- and 90-day outcomes. However, effects were largely driven by patients who had residual congestion at the time of renal function assessment. URL: https://www.clinicaltrials.gov. Unique identifiers: NCT00328692 and NCT00354458. © 2018 American Heart Association, Inc.

Investigating the effect of freeway congestion thresholds on decision-making inputs.

DOT National Transportation Integrated Search

2010-05-01

Congestion threshold is embedded in the congestion definition. Two basic approaches exist in : current practice for setting the congestion threshold. One common approach uses the free-flow or : unimpeded conditions as the congestion threshold. ...

A Space Object Detection Algorithm using Fourier Domain Likelihood Ratio Test

NASA Astrophysics Data System (ADS)

Becker, D.; Cain, S.

Space object detection is of great importance in the highly dependent yet competitive and congested space domain. Detection algorithms employed play a crucial role in fulfilling the detection component in the situational awareness mission to detect, track, characterize and catalog unknown space objects. Many current space detection algorithms use a matched filter or a spatial correlator to make a detection decision at a single pixel point of a spatial image based on the assumption that the data follows a Gaussian distribution. This paper explores the potential for detection performance advantages when operating in the Fourier domain of long exposure images of small and/or dim space objects from ground based telescopes. A binary hypothesis test is developed based on the joint probability distribution function of the image under the hypothesis that an object is present and under the hypothesis that the image only contains background noise. The detection algorithm tests each pixel point of the Fourier transformed images to make the determination if an object is present based on the criteria threshold found in the likelihood ratio test. Using simulated data, the performance of the Fourier domain detection algorithm is compared to the current algorithm used in space situational awareness applications to evaluate its value.

A Survey on Urban Traffic Management System Using Wireless Sensor Networks.

PubMed

Nellore, Kapileswar; Hancke, Gerhard P

2016-01-27

Nowadays, the number of vehicles has increased exponentially, but the bedrock capacities of roads and transportation systems have not developed in an equivalent way to efficiently cope with the number of vehicles traveling on them. Due to this, road jamming and traffic correlated pollution have increased with the associated adverse societal and financial effect on different markets worldwide. A static control system may block emergency vehicles due to traffic jams. Wireless Sensor networks (WSNs) have gained increasing attention in traffic detection and avoiding road congestion. WSNs are very trendy due to their faster transfer of information, easy installation, less maintenance, compactness and for being less expensive compared to other network options. There has been significant research on Traffic Management Systems using WSNs to avoid congestion, ensure priority for emergency vehicles and cut the Average Waiting Time (AWT) of vehicles at intersections. In recent decades, researchers have started to monitor real-time traffic using WSNs, RFIDs, ZigBee, VANETs, Bluetooth devices, cameras and infrared signals. This paper presents a survey of current urban traffic management schemes for priority-based signalling, and reducing congestion and the AWT of vehicles. The main objective of this survey is to provide a taxonomy of different traffic management schemes used for avoiding congestion. Existing urban traffic management schemes for the avoidance of congestion and providing priority to emergency vehicles are considered and set the foundation for further research.

Chest ultrasound and hidden lung congestion in peritoneal dialysis patients.

PubMed

Panuccio, Vincenzo; Enia, Giuseppe; Tripepi, Rocco; Torino, Claudia; Garozzo, Maurizio; Battaglia, Giovanni Giorgio; Marcantoni, Carmelita; Infantone, Lorena; Giordano, Guido; De Giorgi, Maria Loreta; Lupia, Mario; Bruzzese, Vincenzo; Zoccali, Carmine

2012-09-01

Chest ultrasound (US) is a non-invasive well-validated technique for estimating extravascular lung water (LW) in patients with heart diseases and in end-stage renal disease. We systematically applied this technique to the whole peritoneal dialysis (PD) population of five dialysis units. We studied the cross-sectional association between LW, echocardiographic parameters, clinical [pedal oedema, New York Heart Association (NYHA) class] and bioelectrical impedance analysis (BIA) markers of volume status in 88 PD patients. Moderate to severe lung congestion was evident in 41 (46%) patients. Ejection fraction was the echocardiographic parameter with the strongest independent association with LW (r = -0.40 P = 0.002). Oedema did not associate with LW on univariate and multivariate analysis. NYHA class was slightly associated with LW (r = 0.21 P = 0.05). Among patients with severe lung congestion, only 27% had pedal oedema and the majority (57%) had no dyspnoea (NYHA Class I). Similarly, the prevalence of patients with BIA, evidence of volume excess was small (11%) and not significantly different (P = 0.79) from that observed in patients with mild or no congestion (9%). In PD patients, LW by chest US reveals moderate to severe lung congestion in a significant proportion of asymptomatic patients. Intervention studies are necessary to prove the usefulness of chest US for optimizing the control of fluid excess in PD patients.

A Survey on Urban Traffic Management System Using Wireless Sensor Networks

PubMed Central

Nellore, Kapileswar; Hancke, Gerhard P.

2016-01-01

Nowadays, the number of vehicles has increased exponentially, but the bedrock capacities of roads and transportation systems have not developed in an equivalent way to efficiently cope with the number of vehicles traveling on them. Due to this, road jamming and traffic correlated pollution have increased with the associated adverse societal and financial effect on different markets worldwide. A static control system may block emergency vehicles due to traffic jams. Wireless Sensor networks (WSNs) have gained increasing attention in traffic detection and avoiding road congestion. WSNs are very trendy due to their faster transfer of information, easy installation, less maintenance, compactness and for being less expensive compared to other network options. There has been significant research on Traffic Management Systems using WSNs to avoid congestion, ensure priority for emergency vehicles and cut the Average Waiting Time (AWT) of vehicles at intersections. In recent decades, researchers have started to monitor real-time traffic using WSNs, RFIDs, ZigBee, VANETs, Bluetooth devices, cameras and infrared signals. This paper presents a survey of current urban traffic management schemes for priority-based signalling, and reducing congestion and the AWT of vehicles. The main objective of this survey is to provide a taxonomy of different traffic management schemes used for avoiding congestion. Existing urban traffic management schemes for the avoidance of congestion and providing priority to emergency vehicles are considered and set the foundation for further research. PMID:26828489

Aspects of IVHS architecture design

DOT National Transportation Integrated Search

1991-09-17

IVHS systems influence four kinds of decisions that drivers make during their trip. The : corresponding tasks that IVHS systems carry out are route and flow control, congestion : control, vehicle coordination, and spacing. A comparison of two scenari...

Reducing congestion : congestion pricing has promise for improving use of transportation infrastructure

DOT National Transportation Integrated Search

2003-05-06

Congestion pricing can potentially reduce congestion by providing incentives for drivers to shift trips to off-peak periods, use less congested routes, or use alternative modes, thereby spreading out demand for available transportation infrastructure...

SDTCP: Towards Datacenter TCP Congestion Control with SDN for IoT Applications

PubMed Central

Lu, Yifei; Ling, Zhen; Zhu, Shuhong; Tang, Ling

2017-01-01

The Internet of Things (IoT) has gained popularity in recent years. Today’s IoT applications are now increasingly deployed in cloud platforms to perform Big Data analytics. In cloud data center networks (DCN), TCP incast usually happens when multiple senders simultaneously communicate with a single receiver. However, when TCP incast happens, DCN may suffer from both throughput collapse for TCP burst flows and temporary starvation for TCP background flows. In this paper, we propose a software defined network (SDN)-based TCP congestion control mechanism, referred to as SDTCP, to leverage the features, e.g., centralized control methods and the global view of the network, in order to solve the TCP incast problems. When we detect network congestion on an OpenFlow switch, our controller can select the background flows and reduce their bandwidth by adjusting the advertised window of TCP ACK packets of the corresponding background flows so as to reserve more bandwidth for burst flows. SDTCP is transparent to the end systems and can accurately decelerate the rate of background flows by leveraging the global view of the network gained via SDN. The experiments demonstrate that our SDTCP can provide high tolerance for burst flows and achieve better flow completion time for short flows. Therefore, SDTCP is an effective and scalable solution for the TCP incast problem. PMID:28075347

Forearm vasodilatation following release of venous congestion

PubMed Central

Caro, C. G.; Foley, T. H.; Sudlow, M. F.

1970-01-01

1. The volume rate of forearm blood flow was measured with a mercury-in-rubber strain gauge, or with a water-filled plethysmograph, from 1 sec after termination of a 2-3 min period of venous congestion. 2. When congesting pressure had been less than 18 mm Hg, average post-congestion flow (five subjects) was constant during approx. 10 sec and not significantly different from resting flow. 3. When congesting pressure had been 30 mm Hg, average post-congestion flow (eight subjects) was 26% higher than resting, during 3-4 sec after release of congestion, but rose to 273% of resting during 4-6 sec after release of congestion. 4. In other studies forearm vascular resistance had been found normal or increased during such venous congestion, and theoretical studies here indicated that passive mechanical factors could not account for the delayed occurrence of high post-congestion flow. 5. It appears, therefore, that the forearm vascular bed dilates actively shortly after release of substantial venous congestion. It would seem more likely that a myogenic mechanism, rather than a metabolic one, is responsible. PMID:5532541

Algorithm of pulmonary emphysema extraction using thoracic 3-D CT images

NASA Astrophysics Data System (ADS)

Saita, Shinsuke; Kubo, Mitsuru; Kawata, Yoshiki; Niki, Noboru; Nakano, Yasutaka; Ohmatsu, Hironobu; Tominaga, Keigo; Eguchi, Kenji; Moriyama, Noriyuki

2008-03-01

Emphysema patients have the tendency to increase due to aging and smoking. Emphysematous disease destroys alveolus and to repair is impossible, thus early detection is essential. CT value of lung tissue decreases due to the destruction of lung structure. This CT value becomes lower than the normal lung- low density absorption region or referred to as Low Attenuation Area (LAA). So far, the conventional way of extracting LAA by simple thresholding has been proposed. However, the CT value of CT image fluctuates due to the measurement conditions, with various bias components such as inspiration, expiration and congestion. It is therefore necessary to consider these bias components in the extraction of LAA. We removed these bias components and we proposed LAA extraction algorithm. This algorithm has been applied to the phantom image. Then, by using the low dose CT(normal: 30 cases, obstructive lung disease: 26 cases), we extracted early stage LAA and quantitatively analyzed lung lobes using lung structure.

Traffic signal synchronization in the saturated high-density grid road network.

PubMed

Hu, Xiaojian; Lu, Jian; Wang, Wei; Zhirui, Ye

2015-01-01

Most existing traffic signal synchronization strategies do not perform well in the saturated high-density grid road network (HGRN). Traffic congestion often occurs in the saturated HGRN, and the mobility of the network is difficult to restore. In order to alleviate traffic congestion and to improve traffic efficiency in the network, the study proposes a regional traffic signal synchronization strategy, named the long green and long red (LGLR) traffic signal synchronization strategy. The essence of the strategy is to control the formation and dissipation of queues and to maximize the efficiency of traffic flows at signalized intersections in the saturated HGRN. With this strategy, the same signal control timing plan is used at all signalized intersections in the HGRN, and the straight phase of the control timing plan has a long green time and a long red time. Therefore, continuous traffic flows can be maintained when vehicles travel, and traffic congestion can be alleviated when vehicles stop. Using the strategy, the LGLR traffic signal synchronization model is developed, with the objective of minimizing the number of stops. Finally, the simulation is executed to analyze the performance of the model by comparing it to other models, and the superiority of the LGLR model is evident in terms of delay, number of stops, queue length, and overall performance in the saturated HGRN.

Research on Urban Road Traffic Congestion Charging Based on Sustainable Development

NASA Astrophysics Data System (ADS)

Ye, Sun

Traffic congestion is a major problem which bothers our urban traffic sustainable development at present. Congestion charging is an effective measure to alleviate urban traffic congestion. The paper first probes into several key issues such as the goal, the pricing, the scope, the method and the redistribution of congestion charging from theoretical angle. Then it introduces congestion charging practice in Singapore and London and draws conclusion and suggestion that traffic congestion charging should take scientific plan, support of public, public transportation development as the premise.

Features of acute liver congestion on gadoxetate disodium-enhanced MRI in a rat model: Role of organic anion-transporting polypeptide 1A1.

PubMed

Shimizu, Akira; Kobayashi, Akira; Motoyama, Hiroaki; Sakai, Hiroshi; Yamada, Akira; Yoshizawa, Akihiko; Momose, Masanobu; Kadoya, Masumi; Miyagawa, Shin-ichi

2015-09-01

To evaluate the features of hepatic congestion on gadoxetate disodium (Gd-EOB-DTPA)-enhanced magnetic resonance imaging (MRI) and the mechanisms responsible for the radiological findings in a rat model of partial liver congestion. A conventional T1 -weighted spin-echo sequence of the liver was performed using a 1.5T magnetic resonance imager with an 80-mm magnetic aperture for animal studies. We induced regional congestion using partial left lateral hepatic vein ligation (n = 5) and evaluated the following in both congestive liver (CL) and noncongestive liver (non-CL): 1) chronological changes in the relative enhancement (RE) up to 60 minutes after Gd-EOB-DTPA administration, and 2) mRNA and protein expression of rat organic anion transporting protein 1a1 (Oatp1a1). The RE in the CL reached a small peak (18%) at 5 minutes, corresponding to approximately half of the value observed in the non-CL, then slowly decreased in a linear manner thereafter. The degree of RE in the CL was significantly lower than that in the non-CL for up to 30 minutes (P < 0.05). An immunohistological examination showed that Oatp1a1 protein expression was downregulated in the CL. The mRNA level of Oatp1a1 in the CL was significantly upregulated, compared with that in control rat liver (P = 0.046), whereas no significant difference was observed between the CL and the non-CL (P = 0.698). The reduced signal intensity in the CL on Gd-EOB-DTPA-enhanced MRI could be explained by the decreased uptake of Gd-EOB-DTPA via Oatp1a1 protein in the congestive area. © 2015 Wiley Periodicals, Inc.

Integration of off-ramp and arterial signal controls to minimize the recurrent congestion on the I-495 Capital Beltway.

DOT National Transportation Integrated Search

2010-11-01

This study developed an integrated control model to contend with the impact of off-ramp queue spillback on both the freeway and arterials within the interchange control boundaries. The entire control system consists of two levels that compute the opt...

Interaction between worsening renal function and persistent congestion in acute decompensated heart failure.

PubMed

Wattad, Malak; Darawsha, Wisam; Solomonica, Amir; Hijazi, Maher; Kaplan, Marielle; Makhoul, Badira F; Abassi, Zaid A; Azzam, Zaher S; Aronson, Doron

2015-04-01

Worsening renal function (WRF) and congestion are inextricably related pathophysiologically, suggesting that WRF occurring in conjunction with persistent congestion would be associated with worse clinical outcome. We studied the interdependence between WRF and persistent congestion in 762 patients with acute decompensated heart failure (HF). WRF was defined as ≥0.3 mg/dl increase in serum creatinine above baseline at any time during hospitalization and persistent congestion as ≥1 sign of congestion at discharge. The primary end point was all-cause mortality with mean follow-up of 15 ± 9 months. Readmission for HF was a secondary end point. Persistent congestion was more common in patients with WRF than in patients with stable renal function (51.0% vs 26.6%, p <0.0001). Both persistent congestion and persistent WRF were significantly associated with mortality (both p <0.0001). There was a strong interaction (p = 0.003) between persistent WRF and congestion, such that the increased risk for mortality occurred predominantly with both WRF and persistent congestion. The adjusted hazard ratio for mortality in patients with persistent congestion as compared with those without was 4.16 (95% confidence interval [CI] 2.20 to 7.86) in patients with WRF and 1.50 (95% CI 1.16 to 1.93) in patients without WRF. In conclusion, persisted congestion is frequently associated with WRF. We have identified a substantial interaction between persistent congestion and WRF such that congestion portends increased mortality particularly when associated with WRF. Copyright © 2015 Elsevier Inc. All rights reserved.

Multi-time scale control of demand flexibility in smart distribution networks

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

Bhattarai, Bishnu; Myers, Kurt; Bak-Jensen, Birgitte

This study presents a multi-timescale control strategy to deploy demand flexibilities of electric vehicles (EV) for providing system balancing and local congestion management by simultaneously ensuring economic benefits to participating actors. First, the EV charging problem from consumer, aggregator, and grid operator’s perspective is investigated. A hierarchical control architecture (HCA) comprising scheduling, coordinative, and adaptive layers is then designed to realize their coordinative goal. This is realized by integrating a multi-time scale control, which works from a day-ahead scheduling up to real-time adaptive control. The performance of the developed method is investigated with high EV penetration in a typical distributionmore » network. The simulation results demonstrates that HCA exploit EV flexibility to solve grid unbalancing and congestions with simultaneous maximization of economic benefits by ensuring EV participation to day-ahead, balancing, and regulation markets. For the given network configuration and pricing structure, HCA ensures the EV owners to get paid up to 5 times the cost they were paying without control.« less

Multi-time scale control of demand flexibility in smart distribution networks

DOE PAGES

Bhattarai, Bishnu; Myers, Kurt; Bak-Jensen, Birgitte; ...

2017-01-01

This study presents a multi-timescale control strategy to deploy demand flexibilities of electric vehicles (EV) for providing system balancing and local congestion management by simultaneously ensuring economic benefits to participating actors. First, the EV charging problem from consumer, aggregator, and grid operator’s perspective is investigated. A hierarchical control architecture (HCA) comprising scheduling, coordinative, and adaptive layers is then designed to realize their coordinative goal. This is realized by integrating a multi-time scale control, which works from a day-ahead scheduling up to real-time adaptive control. The performance of the developed method is investigated with high EV penetration in a typical distributionmore » network. The simulation results demonstrates that HCA exploit EV flexibility to solve grid unbalancing and congestions with simultaneous maximization of economic benefits by ensuring EV participation to day-ahead, balancing, and regulation markets. For the given network configuration and pricing structure, HCA ensures the EV owners to get paid up to 5 times the cost they were paying without control.« less

Synthesis Study on Transitions in Signal Infrastructure and Control Algorithms for Connected and Automated Transportation

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

Aziz, H. M. Abdul; Wang, Hong; Young, Stan

Documenting existing state of practice is an initial step in developing future control infrastructure to be co-deployed for heterogeneous mix of connected and automated vehicles with human drivers while leveraging benefits to safety, congestion, and energy. With advances in information technology and extensive deployment of connected and automated vehicle technology anticipated over the coming decades, cities globally are making efforts to plan and prepare for these transitions. CAVs not only offer opportunities to improve transportation systems through enhanced safety and efficient operations of vehicles. There are also significant needs in terms of exploring how best to leverage vehicle-to-vehicle (V2V) technology,more » vehicle-to-infrastructure (V2I) technology and vehicle-to-everything (V2X) technology. Both Connected Vehicle (CV) and Connected and Automated Vehicle (CAV) paradigms feature bi-directional connectivity and share similar applications in terms of signal control algorithm and infrastructure implementation. The discussion in our synthesis study assumes the CAV/CV context where connectivity exists with or without automated vehicles. Our synthesis study explores the current state of signal control algorithms and infrastructure, reports the completed and newly proposed CV/CAV deployment studies regarding signal control schemes, reviews the deployment costs for CAV/AV signal infrastructure, and concludes with a discussion on the opportunities such as detector free signal control schemes and dynamic performance management for intersections, and challenges such as dependency on market adaptation and the need to build a fault-tolerant signal system deployment in a CAV/CV environment. The study will serve as an initial critical assessment of existing signal control infrastructure (devices, control instruments, and firmware) and control schemes (actuated, adaptive, and coordinated-green wave). Also, the report will help to identify the future needs for the signal infrastructure to act as the nervous system for urban transportation networks, providing not only signaling, but also observability, surveillance, and measurement capacity. The discussion of the opportunities space includes network optimization and control theory perspectives, and the current states of observability for key system parameters (what can be detected, how frequently can it be reported) as well as controllability of dynamic parameters (this includes adjusting not only the signal phase and timing, but also the ability to alter vehicle trajectories through information or direct control). The perspective of observability and controllability of the dynamic systems provides an appropriate lens to discuss future directions as CAV/CV become more prevalent in the future.« less

A real-time path rating calculation tool powered by HPC

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

If transmission path ratings are determined in real time and optimized control methods can be implemented, congestion problems can be more effectively managed using the existing transmission assets, reducing congestion costs, avoiding capital expenditures for new physical assets, increasing revenues from the existing system, and maintaining reliability. In just one illustrative case, a BPA study has shown that a 1000-MW rating increase for a transmission path generates $15M in annual revenue, even if only 25% of the increased margin can be tapped for just 25% of the year.

Intelligent Traffic Quantification System

NASA Astrophysics Data System (ADS)

Mohanty, Anita; Bhanja, Urmila; Mahapatra, Sudipta

2017-08-01

Currently, city traffic monitoring and controlling is a big issue in almost all cities worldwide. Vehicular ad-hoc Network (VANET) technique is an efficient tool to minimize this problem. Usually, different types of on board sensors are installed in vehicles to generate messages characterized by different vehicle parameters. In this work, an intelligent system based on fuzzy clustering technique is developed to reduce the number of individual messages by extracting important features from the messages of a vehicle. Therefore, the proposed fuzzy clustering technique reduces the traffic load of the network. The technique also reduces congestion and quantifies congestion.

Auctionable fixed transmission rights for congestion management

NASA Astrophysics Data System (ADS)

Alomoush, Muwaffaq Irsheid

Electric power deregulation has proposed a major change to the regulated utility monopoly. The change manifests the main part of engineers' efforts to reshape three components of today's regulated monopoly: generation, distribution and transmission. In this open access deregulated power market, transmission network plays a major role, and transmission congestion is a major problem that requires further consideration especially when inter-zonal/intra-zonal scheme is implemented. Declaring that engineering studies and experience are the criteria to define zonal boundaries or defining a zone based on the fact that a zone is a densely interconnected area (lake) and paths connecting these densely interconnected areas are inter-zonal lines will render insufficient and fuzzy definitions. Moreover, a congestion problem formulation should take into consideration interactions between intra-zonal and inter-zonal flows and their effects on power systems. In this thesis, we introduce a procedure for minimizing the number of adjustments of preferred schedules to alleviate congestion and apply control schemes to minimize interactions between zones. In addition, we give the zone definition a certain criterion based on the Locational Marginal Price (LMP). This concept will be used to define congestion zonal boundaries and to decide whether any zone should be merged with another zone or split into new zones. The thesis presents a unified scheme that combines zonal and FTR schemes to manage congestion. This combined scheme is utilized with LMPs to define zonal boundaries more appropriately. The presented scheme gains the best features of the FTR scheme, which are providing financial certainty, maximizing the efficient use of the system and making users pay for the actual use of congested paths. LMPs may give an indication of the impact of wheeling transactions, and calculations of and comparisons of LMPs with and without wheeling transactions should be adequate criteria to approve the transaction by the ISO, take a decision to expand the existing system, or retain the original structure of the system. Also, the thesis investigates the impact of wheeling transactions on congestion management, where we present a generalized mathematical model for the Fixed Transmission Right (FTR) auction. The auction guarantees FTR availability to all participants on a non-discriminatory basis, in which system users are permitted to buy, sell and trade FTRs through an auction. When FTRs are utilized with LMPs, they increase the efficient use of the transmission system and let a transmission customer gain advantageous features such as acquiring a mechanism to offset the extra cost due to congestion charges, providing financial and operational certainty and making system users pay for the actual use of the congested paths. The thesis also highlighted FTR trading in secondary markets to self-arrange access across different paths, create long-term transmission rights and provide more commercial certainty.

Dynamic airspace configuration algorithms for next generation air transportation system

NASA Astrophysics Data System (ADS)

Wei, Jian

The National Airspace System (NAS) is under great pressure to safely and efficiently handle the record-high air traffic volume nowadays, and will face even greater challenge to keep pace with the steady increase of future air travel demand, since the air travel demand is projected to increase to two to three times the current level by 2025. The inefficiency of traffic flow management initiatives causes severe airspace congestion and frequent flight delays, which cost billions of economic losses every year. To address the increasingly severe airspace congestion and delays, the Next Generation Air Transportation System (NextGen) is proposed to transform the current static and rigid radar based system to a dynamic and flexible satellite based system. New operational concepts such as Dynamic Airspace Configuration (DAC) have been under development to allow more flexibility required to mitigate the demand-capacity imbalances in order to increase the throughput of the entire NAS. In this dissertation, we address the DAC problem in the en route and terminal airspace under the framework of NextGen. We develop a series of algorithms to facilitate the implementation of innovative concepts relevant with DAC in both the en route and terminal airspace. We also develop a performance evaluation framework for comprehensive benefit analyses on different aspects of future sector design algorithms. First, we complete a graph based sectorization algorithm for DAC in the en route airspace, which models the underlying air route network with a weighted graph, converts the sectorization problem into the graph partition problem, partitions the weighted graph with an iterative spectral bipartition method, and constructs the sectors from the partitioned graph. The algorithm uses a graph model to accurately capture the complex traffic patterns of the real flights, and generates sectors with high efficiency while evenly distributing the workload among the generated sectors. We further improve the robustness and efficiency of the graph based DAC algorithm by incorporating the Multilevel Graph Partitioning (MGP) method into the graph model, and develop a MGP based sectorization algorithm for DAC in the en route airspace. In a comprehensive benefit analysis, the performance of the proposed algorithms are tested in numerical simulations with Enhanced Traffic Management System (ETMS) data. Simulation results demonstrate that the algorithmically generated sectorizations outperform the current sectorizations in different sectors for different time periods. Secondly, based on our experience with DAC in the en route airspace, we further study the sectorization problem for DAC in the terminal airspace. The differences between the en route and terminal airspace are identified, and their influence on the terminal sectorization is analyzed. After adjusting the graph model to better capture the unique characteristics of the terminal airspace and the requirements of terminal sectorization, we develop a graph based geometric sectorization algorithm for DAC in the terminal airspace. Moreover, the graph based model is combined with the region based sector design method to better handle the complicated geometric and operational constraints in the terminal sectorization problem. In the benefit analysis, we identify the contributing factors to terminal controller workload, define evaluation metrics, and develop a bebefit analysis framework for terminal sectorization evaluation. With the evaluation framework developed, we demonstrate the improvements on the current sectorizations with real traffic data collected from several major international airports in the U.S., and conduct a detailed analysis on the potential benefits of dynamic reconfiguration in the terminal airspace. Finally, in addition to the research on the macroscopic behavior of a large number of aircraft, we also study the dynamical behavior of individual aircraft from the perspective of traffic flow management. We formulate the mode-confusion problem as hybrid estimation problem, and develop a state estimation algorithm for the linear hybrid system with continuous-state-dependent transitions based on sparse observations. We also develop an estimated time of arrival prediction algorithm based on the state-dependent transition hybrid estimation algorithm, whose performance is demonstrated with simulations on the landing procedure following the Continuous Descend Approach (CDA) profile.

Local search to improve coordinate-based task mapping

DOE PAGES

Balzuweit, Evan; Bunde, David P.; Leung, Vitus J.; ...

2015-10-31

We present a local search strategy to improve the coordinate-based mapping of a parallel job’s tasks to the MPI ranks of its parallel allocation in order to reduce network congestion and the job’s communication time. The goal is to reduce the number of network hops between communicating pairs of ranks. Our target is applications with a nearest-neighbor stencil communication pattern running on mesh systems with non-contiguous processor allocation, such as Cray XE and XK Systems. Utilizing the miniGhost mini-app, which models the shock physics application CTH, we demonstrate that our strategy reduces application running time while also reducing the runtimemore » variability. Furthermore, we further show that mapping quality can vary based on the selected allocation algorithm, even between allocation algorithms of similar apparent quality.« less

Civil Aviation Research and Development /CARD/ Policy Study.

NASA Technical Reports Server (NTRS)

Syvertson, C. A.

1971-01-01

The results of the study lead to a number of conclusions regarding priority areas for R and D. It was found that aircraft noise abatement deserves highest priority because of widespread concern for the environment and because the success of the noise-abatement program will affect the solutions to other problems. Congestion is next on the list of priority problems. Its solution will involve an organized effort directed at the combination of air traffic control, runway capacity, ground control of aircraft, terminal processing, access and egress, parking, and airport location, acquisition, and development. A new short-haul system could help relieve congestion at existing airports. Constant improvements in technology for long-haul vehicles and their propulsion systems are essential to continued U.S. leadership.

Predictive onboard flow control for packet switching satellites

NASA Technical Reports Server (NTRS)

Bobinsky, Eric A.

1992-01-01

We outline two alternate approaches to predicting the onset of congestion in a packet switching satellite, and argue that predictive, rather than reactive, flow control is necessary for the efficient operation of such a system. The first method discussed is based on standard, statistical techniques which are used to periodically calculate a probability of near-term congestion based on arrival rate statistics. If this probability exceeds a present threshold, the satellite would transmit a rate-reduction signal to all active ground stations. The second method discussed would utilize a neural network to periodically predict the occurrence of buffer overflow based on input data which would include, in addition to arrival rates, the distributions of packet lengths, source addresses, and destination addresses.

Oxymetazoline plus dexpanthenol in nasal congestion.

PubMed

Jagade, Mohan V; Langade, Deepak G; Pophale, Rupesh R; Prabhu, Arun

2008-12-01

To compare the efficacy and tolerability of Oxymetazoline 0.05 % plus Dexpanthanol 5% versus Xylometazoline 0.1 % nasal drops in patients with nasal congestion due to allergic rhinitis and following nasal surgery. An investigator-blind, randomized, controlled, phase IV clinical trial conducted in 100 patients with acute allergic rhinitis or patients post-nasal surgery. Patients received either Oxymetazoline 0.05% with Dexpanthanol 5% (OD) or Xylometazoline 0.1% (XO) nasal drops. Relief from nasal congestion was significantly better in the OD group then in the XO group (mean nasal scores 1.24 vs 1.86). Significantly more improvement in sneezing and decrease in nasal discharge was seen in the OD group than the XO group. Nasal irritation in the OD group was significantly less as compared to XO group (0.38 v/s 1.12 on second day and 0.10 vs 0.36 on the fourth day). The recovery time for OD group was 1.08 hours, which was significantly (46 min) lesser than that of the XO group. Rebound congestion was significantly less in OD as compared to XO group (6.25% vs 82.98%). 93.75% of the physicians in the OD group and 51.28% in XO group reported response to therapy as good to excellent. 95.83% patients in the OD group and only 52.91% patients in the XO group rated tolerability to therapy as good to excellent. Oxymetazoline and dexpanthenol combination has a better efficacy, shorter recovery time, causes lesser rebound congestion and has better tolerability than xylometazoline.

Auction Mechanism to Allocate Air Traffic Control Slots

NASA Technical Reports Server (NTRS)

Raffarin, Marianne

2003-01-01

This article deals with an auction mechanism for airspace slots, as a means of solving the European airspace congestion problem. A disequilibrium, between Air Traffic Control (ATC) services supply and ATC services demand are at the origin of almost one fourth of delays in the air transport industry in Europe. In order to tackle this congestion problem, we suggest modifying both pricing and allocation of ATC services, by setting up an auction mechanism. Objects of the auction will be the right for airlines to cross a part of the airspace, and then to benefit from ATC services over a period corresponding to the necessary time for the crossing. Allocation and payment rules have to be defined according to the objectives of this auction. The auctioneer is the public authority in charge of ATC services, whose aim is to obtain an efficient allocation. Therefore, the social value will be maximized. Another objective is to internalize congestion costs. To that end, we apply the principle of Clarke-Groves mechanism auction: each winner has to pay the externalities imposed on other bidders. The complex context of ATC leads to a specific design for this auction.

Constraints of nonresponding flows based on cross layers in the networks

NASA Astrophysics Data System (ADS)

Zhou, Zhi-Chao; Xiao, Yang; Wang, Dong

2016-02-01

In the active queue management (AQM) scheme, core routers cannot manage and constrain user datagram protocol (UDP) data flows by the sliding window control mechanism in the transport layer due to the nonresponsive nature of such traffic flows. However, the UDP traffics occupy a large part of the network service nowadays which brings a great challenge to the stability of the more and more complex networks. To solve the uncontrollable problem, this paper proposes a cross layers random early detection (CLRED) scheme, which can control the nonresponding UDP-like flows rate effectively when congestion occurs in the access point (AP). The CLRED makes use of the MAC frame acknowledgement (ACK) transmitting congestion information to the sources nodes and utilizes the back-off windows of the MAC layer throttling data rate. Consequently, the UDP-like flows data rate can be restrained timely by the sources nodes in order to alleviate congestion in the complex networks. The proposed CLRED can constrain the nonresponsive flows availably and make the communication expedite, so that the network can sustain stable. The simulation results of network simulator-2 (NS2) verify the proposed CLRED scheme.

Development of «Park-and-Ride» system as a tool for sustainable access control managing

NASA Astrophysics Data System (ADS)

Danilina, Nina; Vlasov, Denis

2017-10-01

Large cities, whereby people use private transport, are facing the same challenges related to traffic congestion, reliability of public transportation and parking demand. Managing urban traffic and transport has become the most relevant police in transport planning. The article deals with the potential for further implementation in Russian Federation of «Park-and- Ride» recognized as an essential part of the overall transport and parking offer and successful planning tool to reducing congestion for any urban area around the world. The studies have been carried out in Moscow acknowledged as the city core of Moscow agglomeration — the largest and most populous in Russia. The research aims to support for the development of «Park-and-Ride» system applying the methodical approach adapted by the authors for the study to make it relevant for cities. A three-steps access control is offered to reduce private cars use in the city center. The results of the studies shows that such traffic management tool can help successfully in balancing the traffic demand and supply and, consequently, in resolving transport congestion and the number of coherent social, urban and economic challenges addressed to the sustainable development of urban areas.

Convective Weather Avoidance with Uncertain Weather Forecasts

NASA Technical Reports Server (NTRS)

Karahan, Sinan; Windhorst, Robert D.

2009-01-01

Convective weather events have a disruptive impact on air traffic both in terminal area and in en-route airspaces. In order to make sure that the national air transportation system is safe and efficient, it is essential to respond to convective weather events effectively. Traffic flow control initiatives in response to convective weather include ground delay, airborne delay, miles-in-trail restrictions as well as tactical and strategic rerouting. The rerouting initiatives can potentially increase traffic density and complexity in regions neighboring the convective weather activity. There is a need to perform rerouting in an intelligent and efficient way such that the disruptive effects of rerouting are minimized. An important area of research is to study the interaction of in-flight rerouting with traffic congestion or complexity and developing methods that quantitatively measure this interaction. Furthermore, it is necessary to find rerouting solutions that account for uncertainties in weather forecasts. These are important steps toward managing complexity during rerouting operations, and the paper is motivated by these research questions. An automated system is developed for rerouting air traffic in order to avoid convective weather regions during the 20- minute - 2-hour time horizon. Such a system is envisioned to work in concert with separation assurance (0 - 20-minute time horizon), and longer term air traffic management (2-hours and beyond) to provide a more comprehensive solution to complexity and safety management. In this study, weather is dynamic and uncertain; it is represented as regions of airspace that pilots are likely to avoid. Algorithms are implemented in an air traffic simulation environment to support the research study. The algorithms used are deterministic but periodically revise reroutes to account for weather forecast updates. In contrast to previous studies, in this study convective weather is represented as regions of airspace that pilots are likely to avoid. The automated system periodically updates forecasts and reassesses rerouting decisions in order to account for changing weather predictions. The main objectives are to reroute flights to avoid convective weather regions and determine the resulting complexity due to rerouting. The eventual goal is to control and reduce complexity while rerouting flights during the 20 minute - 2 hour planning period. A three-hour simulation is conducted using 4800 flights in the national airspace. The study compares several metrics against a baseline scenario using the same traffic and weather but with rerouting disabled. The results show that rerouting can have a negative impact on congestion in some sectors, as expected. The rerouting system provides accurate measurements of the resulting complexity in the congested sectors. Furthermore, although rerouting is performed only in the 20-minute - 2-hour range, it results in a 30% reduction in encounters with nowcast weather polygons (100% being the ideal for perfectly predictable and accurate weather). In the simulations, rerouting was performed for the 20-minute - 2-hour flight time horizon, and for the en-route segment of air traffic. The implementation uses CWAM, a set of polygons that represent probabilities of pilot deviation around weather. The algorithms were implemented in a software-based air traffic simulation system. Initial results of the system's performance and effectiveness were encouraging. Simulation results showed that when flights were rerouted in the 20-minute - 2-hour flight time horizon of air traffic, there were fewer weather encounters in the first 20 minutes than for flights that were not rerouted. Some preliminary results were also obtained that showed that rerouting will also increase complexity. More simulations will be conducted in order to report conclusive results on the effects of rerouting on complexity. Thus, the use of the 20-minute - 2-hour flight time horizon weather avoidance teniques performed in the simulation is expected to provide benefits for short-term weather avoidance.

A Study of the Effects of Congestion Information and a Priority Boarding Pass in a Theme Park with Multi-Agents

NASA Astrophysics Data System (ADS)

Tone, Tetsuya; Kohara, Kazuhiro

We have investigated ways to reduce congestion in a theme park with multi-agents. We constructed a theme park model called Digital Park 1.0 with twenty-three attractions similar in form to Tokyo Disney Sea. We consider not only congestion information (number of vistors standing in line at each attraction) but also the advantage of a priority boarding pass, like Fast Pass which is used at Tokyo Disney Sea. The congestion-information-usage ratio, which reflects the ratio of visitors who behave according to congestion information, was changed from 0% to 100% in both models, with and without priority boarding pass. The “mean stay time of visitors" is a measure of satisfaction. The smaller mean stay time, the larger degree of satisfaction. Here, a short stay time means a short wait time. The resluts of each simulation are averaged over ten trials. The main results are as follows. (1) When congestion-information-usage ratio increased, the mean stay time decreases. When 20% of visitors behaved according to congestion information, the mean stay time was reduced by 30%. (2) A priority boarding pass reduced congestion, and mean stay time was reduced by 15%. (3) When visitors used congestion information and a priority boarding pass, mean stay time was further reduced. When the congestion-information-usage ratio was 20%, mean stay time was reduced by 35%. (4) When congestion-information-usage ratio was over 50%, the congestion reduction effects reached saturation.

Survival and prognosis: investigation of Crataegus extract WS 1442 in congestive heart failure (SPICE)--rationale, study design and study protocol.

PubMed

Holubarsch, C J; Colucci, W S; Meinertz, T; Gaus, W; Tendera, M

2000-12-01

SPICE is the first, international, randomized, placebo-controlled, double-blind study to investigate the influence of the herbal drug Crataegus Special Extract WS 1442 (hawthorn leaves with flowers) on mortality of patients suffering from congestive heart failure. In vitro and experimental animal studies have suggested the following pharmacological modes of action of standardized Crataegus extracts: (1) cAMP-independent positive inotropy; (2) peripheral and coronary vasodilation; (3) protection against ischemia-induced ventricular arrhythmias; (4) antioxidative properties; and (5) anti-inflammatory effects. In this randomized, placebo-controlled, double-blind, international trial (approximately 120 investigational centers in seven European countries), up to 2300 patients with congestive heart failure, New York Heart Association class II and III and markedly impaired left ventricular function, will be enrolled and treated over a period of 24 months. During this time patients receive either two film-coated tablets of 450 mg of the Special Extract WS 1442 standardized to 84.3 mg of oligomeric procyanidines or matched placebo per day in addition to standard therapy for congestive heart failure, such as diuretics, digoxin or digitoxin, beta-adrenoceptor blockers and angiotensin-converting-enzyme inhibitors. The primary outcome variable is the combined endpoint of cardiac death, non-lethal myocardial infarction, and hospitalization due to progression of heart failure. Secondary outcome variables are total mortality, exercise duration, echocardiographic parameters, quality of life as well as pharmacoeconomic parameters. The first patient was included in October 1998. The trial is expected to be completed at the end of 2002.

Treating Chronically Ill Diabetic Patients with Limited Life Expectancy: Implications for Performance Measurement

PubMed Central

Woodard, LeChauncy D.; Landrum, Cassie R.; Urech, Tracy H.; Profit, Jochen; Virani, Salim S.; Petersen, Laura A.

2012-01-01

Background/Objectives To validly assess quality-of-care differences among providers, performance measurement programs must reliably identify and exclude patients for whom the quality indicator may not be desirable, including those with limited life expectancy. We developed an algorithm to identify patients with limited life expectancy and examined the impact of limited life expectancy on glycemic control and treatment intensification among diabetic patients. Design We identified diabetic patients with coexisting congestive heart failure, chronic obstructive pulmonary disease, dementia, end-stage liver disease, and/or primary/metastatic cancers with limited life expectancy. To validate our algorithm, we assessed 5-year mortality among patients identified as having limited life expectancy. We compared rates of meeting performance measures for glycemic control between patients with and without limited life expectancy. Among uncontrolled patients, we examined the impact of limited life expectancy on treatment intensification within 90 days. Setting 110 Veterans Administration facilities; October 2006 – September 2007 Participants 888,628 diabetic patients Measurements Hemoglobin A1c (HbA1c) <9%; treatment intensification within 90 days Results 29,016 (3%) patients had limited life expectancy. Adjusting for age, 5-year mortality was 5 times higher among patients with limited life expectancy than those without. Patients with limited life expectancy had poorer glycemic control (77.1% vs. 78.1%) and less frequent treatment intensification (20.9% vs. 28.6%) than patients without, even after controlling for patient-level characteristics (odds ratio [OR]=0.84; 95% confidence interval [CI]=0.81-0.86 and OR=0.71; 95% CI=0.67-0.76, respectively). Conclusion Patients with limited life expectancy were slightly, but significantly less likely than those without to have HbA1c levels controlled and to receive treatment intensification, suggesting that providers treat these patients less aggressively. Quality measurement and performance-based reimbursement systems should acknowledge the different needs of this population. PMID:22260627

MicroRNA-133 regulates the expression of GLUT4 by targeting KLF15 and is involved in metabolic control in cardiac myocytes.

PubMed

Horie, Takahiro; Ono, Koh; Nishi, Hitoo; Iwanaga, Yoshitaka; Nagao, Kazuya; Kinoshita, Minako; Kuwabara, Yasuhide; Takanabe, Rieko; Hasegawa, Koji; Kita, Toru; Kimura, Takeshi

2009-11-13

GLUT4 shows decreased levels in failing human adult hearts. We speculated that GLUT4 expression in cardiac muscle may be fine-tuned by microRNAs. Forced expression of miR-133 decreased GLUT4 expression and reduced insulin-mediated glucose uptake in cardiomyocytes. A computational miRNA target prediction algorithm showed that KLF15 is one of the targets of miR-133. It was confirmed that over-expression of miR-133 reduced the protein level of KLF15, which reduced the level of the downstream target GLUT4. Cardiac myocytes infected with lenti-decoy, in which the 3'UTR with tandem sequences complementary to miR-133 was linked to the luciferase reporter gene, had decreased miR-133 levels and increased levels of GLUT4. The expression levels of KLF15 and GLUT4 were decreased at the left ventricular hypertrophy and congestive heart failure stage in a rat model. The present results indicated that miR-133 regulates the expression of GLUT4 by targeting KLF15 and is involved in metabolic control in cardiomyocytes.

Dynamic, stochastic models for congestion pricing and congestion securities.

DOT National Transportation Integrated Search

2010-12-01

This research considers congestion pricing under demand uncertainty. In particular, a robust optimization (RO) approach is applied to optimal congestion pricing problems under user equilibrium. A mathematical model is developed and an analysis perfor...

Traffic Signal Synchronization in the Saturated High-Density Grid Road Network

PubMed Central

Hu, Xiaojian; Lu, Jian; Wang, Wei; Zhirui, Ye

2015-01-01

Most existing traffic signal synchronization strategies do not perform well in the saturated high-density grid road network (HGRN). Traffic congestion often occurs in the saturated HGRN, and the mobility of the network is difficult to restore. In order to alleviate traffic congestion and to improve traffic efficiency in the network, the study proposes a regional traffic signal synchronization strategy, named the long green and long red (LGLR) traffic signal synchronization strategy. The essence of the strategy is to control the formation and dissipation of queues and to maximize the efficiency of traffic flows at signalized intersections in the saturated HGRN. With this strategy, the same signal control timing plan is used at all signalized intersections in the HGRN, and the straight phase of the control timing plan has a long green time and a long red time. Therefore, continuous traffic flows can be maintained when vehicles travel, and traffic congestion can be alleviated when vehicles stop. Using the strategy, the LGLR traffic signal synchronization model is developed, with the objective of minimizing the number of stops. Finally, the simulation is executed to analyze the performance of the model by comparing it to other models, and the superiority of the LGLR model is evident in terms of delay, number of stops, queue length, and overall performance in the saturated HGRN. PMID:25663835

Scheduling and control strategies for the departure problem in air traffic control

NASA Astrophysics Data System (ADS)

Bolender, Michael Alan

Two problems relating to the departure problem in air traffic control automation are examined. The first problem that is addressed is the scheduling of aircraft for departure. The departure operations at a major US hub airport are analyzed, and a discrete event simulation of the departure operations is constructed. Specifically, the case where there is a single departure runway is considered. The runway is fed by two queues of aircraft. Each queue, in turn, is fed by a single taxiway. Two salient areas regarding scheduling are addressed. The first is the construction of optimal departure sequences for the aircraft that are queued. Several greedy search algorithms are designed to minimize the total time to depart a set of queued aircraft. Each algorithm has a different set of heuristic rules to resolve situations within the search space whenever two branches of the search tree with equal edge costs are encountered. These algorithms are then compared and contrasted with a genetic search algorithm in order to assess the performance of the heuristics. This is done in the context of a static departure problem where the length of the departure queue is fixed. A greedy algorithm which deepens the search whenever two branches of the search tree with non-unique costs are encountered is shown to outperform the other heuristic algorithms. This search strategy is then implemented in the discrete event simulation. A baseline performance level is established, and a sensitivity analysis is performed by implementing changes in traffic mix, routing, and miles-in-trail restrictions for comparison. It is concluded that to minimize the average time spent in the queue for different traffic conditions, a queue assignment algorithm is needed to maintain an even balance of aircraft in the queues. A necessary consideration is to base queue assignment upon traffic management restrictions such as miles-in-trail constraints. The second problem addresses the technical challenges associated with merging departure aircraft onto their filed routes in a congested airspace environment. Conflicts between departures and en route aircraft within the Center airspace are analyzed. Speed control, holding the aircraft; at an intermediate altitude, re-routing, and vectoring are posed as possible deconfliction maneuvers. A cost assessment of these merge strategies, which are based upon 4D fight management and conflict detection and resolution principles, is given. Several merge conflicts are studied and a cost for each resolution is computed. It is shown that vectoring tends to be the most expensive resolution technique. Altitude hold is simple, costs less than vectoring, but may require a long time for the aircraft to achieve separation. Re-routing is the simplest, and provides the most cost benefit since the aircraft flies a shorter distance than if it had followed its filed route. Speed control is shown to be ineffective as a means of increasing separation, but is effective for maintaining separation between aircraft. In addition, the affects of uncertainties on the cost are assessed. The analysis shows that cost is invariant with the decision time.

Analysis of Discrete Stated Responses to Parking Pricing Based Transportation Control Measures

DOT National Transportation Integrated Search

1997-01-01

The realization that one can no longer build out of congestion while preserving the urban environment has led to an increasing interest in the potential application of transportation control measures (TCM) for curbing travel demand. One such TCM that...

Traffic congestion and reliability : linking solutions to problems.

DOT National Transportation Integrated Search

2004-07-19

The Traffic Congestion and Reliability: Linking Solutions to Problems Report provides : a snapshot of congestion in the United States by summarizing recent trends in : congestion, highlighting the role of unreliable travel times in the effects of con...

Study on the propagation and dissipation of inland ship congestion under different control strategies

NASA Astrophysics Data System (ADS)

Chen, Yanyi; Wu, Hongyu; Wen, Zhe

2017-05-01

Inland waterway transportation is an important part of the comprehensive transportation system of sustainable development, and it is also a way of transportation which is restricted by natural conditions greatly. In recent years, the problems of insufficient traffic capacity of The Three Gorges become prominent due to the increasing in the number of ships. And the ship's detention caused by gale, frog, accident and one-way traffic in dry season has occurred, which not only increased the pressure of the navigable waterway but also seriously affected the safety of shipping. Based on the different types of ships, the Arena software was used to simulate the ship traffic flow. The paper analyzed the traffic congestion propagation and dissipation rule of the ship under different navigation control methods, and provided decision reference for the navigation management department to formulate the relevant navigation control strategy.

Intelligent Local Avoided Collision (iLAC) MAC Protocol for Very High Speed Wireless Network

NASA Astrophysics Data System (ADS)

Hieu, Dinh Chi; Masuda, Akeo; Rabarijaona, Verotiana Hanitriniala; Shimamoto, Shigeru

Future wireless communication systems aim at very high data rates. As the medium access control (MAC) protocol plays the central role in determining the overall performance of the wireless system, designing a suitable MAC protocol is critical to fully exploit the benefit of high speed transmission that the physical layer (PHY) offers. In the latest 802.11n standard [2], the problem of long overhead has been addressed adequately but the issue of excessive colliding transmissions, especially in congested situation, remains untouched. The procedure of setting the backoff value is the heart of the 802.11 distributed coordination function (DCF) to avoid collision in which each station makes its own decision on how to avoid collision in the next transmission. However, collision avoidance is a problem that can not be solved by a single station. In this paper, we introduce a new MAC protocol called Intelligent Local Avoided Collision (iLAC) that redefines individual rationality in choosing the backoff counter value to avoid a colliding transmission. The distinguishing feature of iLAC is that it fundamentally changes this decision making process from collision avoidance to collaborative collision prevention. As a result, stations can avoid colliding transmissions with much greater precision. Analytical solution confirms the validity of this proposal and simulation results show that the proposed algorithm outperforms the conventional algorithms by a large margin.

A Bayesian ridge regression analysis of congestion's impact on urban expressway safety.

PubMed

Shi, Qi; Abdel-Aty, Mohamed; Lee, Jaeyoung

2016-03-01

With the rapid growth of traffic in urban areas, concerns about congestion and traffic safety have been heightened. This study leveraged both Automatic Vehicle Identification (AVI) system and Microwave Vehicle Detection System (MVDS) installed on an expressway in Central Florida to explore how congestion impacts the crash occurrence in urban areas. Multiple congestion measures from the two systems were developed. To ensure more precise estimates of the congestion's effects, the traffic data were aggregated into peak and non-peak hours. Multicollinearity among traffic parameters was examined. The results showed the presence of multicollinearity especially during peak hours. As a response, ridge regression was introduced to cope with this issue. Poisson models with uncorrelated random effects, correlated random effects, and both correlated random effects and random parameters were constructed within the Bayesian framework. It was proven that correlated random effects could significantly enhance model performance. The random parameters model has similar goodness-of-fit compared with the model with only correlated random effects. However, by accounting for the unobserved heterogeneity, more variables were found to be significantly related to crash frequency. The models indicated that congestion increased crash frequency during peak hours while during non-peak hours it was not a major crash contributing factor. Using the random parameter model, the three congestion measures were compared. It was found that all congestion indicators had similar effects while Congestion Index (CI) derived from MVDS data was a better congestion indicator for safety analysis. Also, analyses showed that the segments with higher congestion intensity could not only increase property damage only (PDO) crashes, but also more severe crashes. In addition, the issues regarding the necessity to incorporate specific congestion indicator for congestion's effects on safety and to take care of the multicollinearity between explanatory variables were also discussed. By including a specific congestion indicator, the model performance significantly improved. When comparing models with and without ridge regression, the magnitude of the coefficients was altered in the existence of multicollinearity. These conclusions suggest that the use of appropriate congestion measure and consideration of multicolilnearity among the variables would improve the models and our understanding about the effects of congestion on traffic safety. Copyright © 2015 Elsevier Ltd. All rights reserved.

Relation of systemic and local muscle exercise capacity to skeletal muscle characteristics in men with congestive heart failure

NASA Technical Reports Server (NTRS)

Massie, B. M.; Simonini, A.; Sahgal, P.; Wells, L.; Dudley, G. A.

1996-01-01

OBJECTIVES. The present study was undertaken to further characterize changes in skeletal muscle morphology and histochemistry in congestive heart failure and to determine the relation of these changes to abnormalities of systemic and local muscle exercise capacity. BACKGROUND. Abnormalities of skeletal muscle appear to play a role in the limitation of exercise capacity in congestive heart failure, but information on the changes in muscle morphology and biochemistry and their relation to alterations in muscle function is limited. METHODS. Eighteen men with predominantly mild to moderate congestive heart failure (mean +/- SEM New York Heart Association functional class 2.6 +/- 0.2, ejection fraction 24 +/- 2%) and eight age- and gender-matched sedentary control subjects underwent measurements of peak systemic oxygen consumption (VO2) during cycle ergometry, resistance to fatigue of the quadriceps femoris muscle group and biopsy of the vastus lateralis muscle. RESULTS. Peak VO2 and resistance to fatigue were lower in the patients with heart failure than in control subjects (15.7 +/- 1.2 vs. 25.1 +/- 1.5 ml/min-kg and 63 +/- 2% vs. 85 +/- 3%, respectively, both p < 0.001). Patients had a lower proportion of slow twitch, type I fibers than did control subjects (36 +/- 3% vs. 46 +/- 5%, p = 0.048) and a higher proportion of fast twitch, type IIab fibers (18 +/- 3% vs. 7 +/- 2%, p = 0.004). Fiber cross-sectional area was smaller, and single-fiber succinate dehydrogenase activity, a mitochondrial oxidative marker, was lower in patients (both p < or = 0.034). Likewise, the ratio of average fast twitch to slow twitch fiber cross-sectional area was lower in patients (0.780 +/- 0.06 vs. 1.05 +/- 0.08, p = 0.019). Peak VO2 was strongly related to integrated succinate dehydrogenase activity in patients (r = 0.896, p = 0.001). Peak VO2, resistance to fatigue and strength also correlated significantly with several measures of fiber size, especially of fast twitch fibers, in patients. None of the skeletal muscle characteristics examined correlated with exercise capacity in control subjects. CONCLUSIONS. These results indicate that congestive heart failure is associated with changes in the characteristics of skeletal muscle and local as well as systemic exercise performance. There are fewer slow twitch fibers, smaller fast twitch fibers and lower succinate dehydrogenase activity. The latter finding suggests that mitochondrial content of muscle is reduced in heart failure and that impaired aerobic-oxidative capacity may play a role in the limitation of systemic exercise capacity.

Mean Field Type Control with Congestion (II): An Augmented Lagrangian Method

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

Achdou, Yves, E-mail: achdou@ljll.univ-paris-diderot.fr; Laurière, Mathieu

This work deals with a numerical method for solving a mean-field type control problem with congestion. It is the continuation of an article by the same authors, in which suitably defined weak solutions of the system of partial differential equations arising from the model were discussed and existence and uniqueness were proved. Here, the focus is put on numerical methods: a monotone finite difference scheme is proposed and shown to have a variational interpretation. Then an Alternating Direction Method of Multipliers for solving the variational problem is addressed. It is based on an augmented Lagrangian. Two kinds of boundary conditionsmore » are considered: periodic conditions and more realistic boundary conditions associated to state constrained problems. Various test cases and numerical results are presented.« less

2012 urban congestion trends, operations : the key to reliable travel.

DOT National Transportation Integrated Search

2013-04-01

Congestion levels remained relatively unchanged : from 2011 to 2012 in the 19 urban areas in the United States monitored : in this report. : Congestion levels across all of the congestion measures are still generally : below the levels experienced in...

Desloratadine and pseudoephedrine combination therapy as a comprehensive treatment for allergic rhinitis and nasal congestion.

PubMed

Anolik, Robert

2009-06-01

Allergic rhinitis (AR) is rapidly increasing in global prevalence. Symptoms of AR, particularly nasal congestion, can cause quality of life (QoL) impairment. Second-generation antihistamines are a recommended first-line therapy for AR but are not viewed as very effective for the treatment of congestion. Therefore, an antihistamine plus a decongestant, such as the combination of desloratadine and pseudoephedrine, is a convenient and efficacious treatment. To review the clinical evidence on the efficacy and safety of combination desloratadine/pseudoephedrine for the treatment of AR symptoms, particularly nasal congestion. Four large studies found that improvement in nasal congestion is enhanced when patients are treated with combination desloratadine/pseudoephedrine. The combination drug significantly improved mean reflective nasal congestion scores in these studies compared with either component as monotherapy (p

Variable message fog hazard warning signs to control vehicle operating characteristics : interim report, Interstate 5, North Albany.

DOT National Transportation Integrated Search

1972-04-01

This project is aimed at determining the effectiveness of variable message signs in controlling traffic on an Interstate highway during periods of hazardous driving conditions such as fog, vehicle accidents, or congestion. : The effectiveness of the ...

14 CFR 93.29 - International Arrival Authorizations.

Code of Federal Regulations, 2011 CFR

2011-01-01

... (CONTINUED) AIR TRAFFIC AND GENERAL OPERATING RULES SPECIAL AIR TRAFFIC RULES Congestion and Delay Reduction... marketing arrangement unless the flight was predominately marketed, by contract, under the control of another Carrier. If the flight was under the marketing control of another Carrier or the entire inventory...

Histopathological changes in dental pulp of rats following radiotherapy

PubMed Central

Madani, Zahra Sadat; Azarakhsh, Soheil; Shakib, Pouyan Amini; Karimi, Masoomeh

2017-01-01

Background: Radiotherapy is one of the oral and pharyngeal cancer treatment methods that can cause damage to the tissues in the radiation area; the purpose of this study is to evaluate the effects of radiotherapy on dental pulp tissue in rats. Materials and Methods: In this interventional, experimental double-blind study, 30 rats were studied in three groups (n = 10 each). The first group received 12 gray (Gy), the second group received 18 Gy in one session, and the third group was not exposed to radiation (control group). The 5 μm sections of mandibular molar tooth were prepared and stained with hematoxylin and eosin. Samples were studied under optical microscope to evaluate and score inflammation, necrosis, hyalinization, and vascular congestion. The data were coded and analyzed by statistical tests of χ2 and Fisher's exact tests. The significant level of P = 0.05. Results: In Group 1, necrosis in two cases, inflammation in one case, hyalinization in one case, and vascular congestion in four cases were observed. In Group 2, inflammation in four cases, hyalinization in two cases, and vascular congestion in five cases were observed. In Group 3, inflammation was observed only in one case. In comparison between the groups, no significant differences were observed in inflammation (P > 0.05), necrosis (P > 0.05), and hyalinization (P > 0.05). However, the difference was significant for vascular congestion (P < 0.05). Conclusion: Radiotherapy with doses of 12 and 18 Gy had no significant effect on inflammation, necrosis, and hyalinization in all groups; however, the difference was significant for vascular congestion. PMID:28348613

A novel encoding Lempel-Ziv complexity algorithm for quantifying the irregularity of physiological time series.

PubMed

Zhang, Yatao; Wei, Shoushui; Liu, Hai; Zhao, Lina; Liu, Chengyu

2016-09-01

The Lempel-Ziv (LZ) complexity and its variants have been extensively used to analyze the irregularity of physiological time series. To date, these measures cannot explicitly discern between the irregularity and the chaotic characteristics of physiological time series. Our study compared the performance of an encoding LZ (ELZ) complexity algorithm, a novel variant of the LZ complexity algorithm, with those of the classic LZ (CLZ) and multistate LZ (MLZ) complexity algorithms. Simulation experiments on Gaussian noise, logistic chaotic, and periodic time series showed that only the ELZ algorithm monotonically declined with the reduction in irregularity in time series, whereas the CLZ and MLZ approaches yielded overlapped values for chaotic time series and time series mixed with Gaussian noise, demonstrating the accuracy of the proposed ELZ algorithm in capturing the irregularity, rather than the complexity, of physiological time series. In addition, the effect of sequence length on the ELZ algorithm was more stable compared with those on CLZ and MLZ, especially when the sequence length was longer than 300. A sensitivity analysis for all three LZ algorithms revealed that both the MLZ and the ELZ algorithms could respond to the change in time sequences, whereas the CLZ approach could not. Cardiac interbeat (RR) interval time series from the MIT-BIH database were also evaluated, and the results showed that the ELZ algorithm could accurately measure the inherent irregularity of the RR interval time series, as indicated by lower LZ values yielded from a congestive heart failure group versus those yielded from a normal sinus rhythm group (p < 0.01). Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Novel Biomarkers of Arterial and Venous Ischemia in Microvascular Flaps

PubMed Central

Nguyen, Gerard K.; Monahan, John F. W.; Davis, Gabrielle B.; Lee, Yong Suk; Ragina, Neli P.; Wang, Charles; Zhou, Zhao Y.; Hong, Young Kwon; Spivak, Ryan M.; Wong, Alex K.

2013-01-01

The field of reconstructive microsurgery is experiencing tremendous growth, as evidenced by recent advances in face and hand transplantation, lower limb salvage after trauma, and breast reconstruction. Common to all of these procedures is the creation of a nutrient vascular supply by microsurgical anastomosis between a single artery and vein. Complications related to occluded arterial inflow and obstructed venous outflow are not uncommon, and can result in irreversible tissue injury, necrosis, and flap loss. At times, these complications are challenging to clinically determine. Since early intervention with return to the operating room to re-establish arterial inflow or venous outflow is key to flap salvage, the accurate diagnosis of early stage complications is essential. To date, there are no biochemical markers or serum assays that can predict these complications. In this study, we utilized a rat model of flap ischemia in order to identify the transcriptional signatures of venous congestion and arterial ischemia. We found that the critical ischemia time for the superficial inferior epigastric fasciocutaneus flap was four hours and therefore performed detailed analyses at this time point. Histolgical analysis confirmed significant differences between arterial and venous ischemia. The transcriptome of ischemic, congested, and control flap tissues was deciphered by performing Affymetrix microarray analysis and verified by qRT-PCR. Principal component analysis revealed that arterial ischemia and venous congestion were characterized by distinct transcriptomes. Arterial ischemia and venous congestion was characterized by 408 and 1536>2-fold differentially expressed genes, respectively. qRT-PCR was used to identify five candidate genes Prol1, Muc1, Fcnb, Il1b, and Vcsa1 to serve as biomarkers for flap failure in both arterial ischemia and venous congestion. Our data suggests that Prol1 and Vcsa1 may be specific indicators of venous congestion and allow clinicians to both diagnose and successfully treat microvascular complications before irreversible tissue damage and flap loss occurs. PMID:23977093

Contemporary approaches to congestion pricing : lessons learned from the national evaluation of congestion pricing strategies at six sites.

DOT National Transportation Integrated Search

2015-08-01

This document represents the final report of the national evaluation of congestion reduction strategies at six sites that received federal funding under the Urban Partnership Agreement (UPA) and Congestion Reduction Demonstration (CRD) programs. The ...

Mobility and the costs of congestion in New Jersey : 2001 update

DOT National Transportation Integrated Search

2001-07-01

The objective of the Mobility and the Costs of Congestion study is to measure quantifiable and qualitative impacts of roadway congestion in New Jersey. The study addresses the impacts of congestion on an average traveler or affected person, as well a...

Diagnosis and management of nasal congestion: the role of intranasal corticosteroids.

PubMed

Benninger, Michael

2009-01-01

Nasal congestion is considered the most bothersome of allergic rhinitis (AR) symptoms and can significantly impair ability to function at work, home, and school. Effective management of AR-related nasal congestion depends on accurate diagnosis and appropriate treatment. Many individuals with AR and AR-related congestion remain undiagnosed and do not receive prescription medication. However, new tools intended to improve the diagnosis of nasal congestion have been developed and validated. Intranasal corticosteroids (INSs) are recommended as first-line therapy for patients with moderate-to-severe AR and also when nasal congestion is a prominent symptom. Double blind, randomized clinical trials have demonstrated greater efficacy of INSs versus placebo, antihistamines, or montelukast for relief of all nasal symptoms, especially congestion. Patient adherence to treatment also affects outcomes, and this may be influenced by patient preferences for the sensory attributes of an individual drug. Increased awareness of the effects of AR-related nasal congestion, the efficacy and safety of available pharmacotherapies, and barriers to adherence may improve clinical outcomes.

Advances in Patch-Based Adaptive Mesh Refinement Scalability

DOE PAGES

Gunney, Brian T.N.; Anderson, Robert W.

2015-12-18

Patch-based structured adaptive mesh refinement (SAMR) is widely used for high-resolution simu- lations. Combined with modern supercomputers, it could provide simulations of unprecedented size and resolution. A persistent challenge for this com- bination has been managing dynamically adaptive meshes on more and more MPI tasks. The dis- tributed mesh management scheme in SAMRAI has made some progress SAMR scalability, but early al- gorithms still had trouble scaling past the regime of 105 MPI tasks. This work provides two critical SAMR regridding algorithms, which are integrated into that scheme to ensure efficiency of the whole. The clustering algorithm is an extensionmore » of the tile- clustering approach, making it more flexible and efficient in both clustering and parallelism. The partitioner is a new algorithm designed to prevent the network congestion experienced by its prede- cessor. We evaluated performance using weak- and strong-scaling benchmarks designed to be difficult for dynamic adaptivity. Results show good scaling on up to 1.5M cores and 2M MPI tasks. Detailed timing diagnostics suggest scaling would continue well past that.« less

Joint optimization of green vehicle scheduling and routing problem with time-varying speeds

PubMed Central

Zhang, Dezhi; Wang, Xin; Ni, Nan; Zhang, Zhuo

2018-01-01

Based on an analysis of the congestion effect and changes in the speed of vehicle flow during morning and evening peaks in a large- or medium-sized city, the piecewise function is used to capture the rules of the time-varying speed of vehicles, which are very important in modelling their fuel consumption and CO2 emission. A joint optimization model of the green vehicle scheduling and routing problem with time-varying speeds is presented in this study. Extra wages during nonworking periods and soft time-window constraints are considered. A heuristic algorithm based on the adaptive large neighborhood search algorithm is also presented. Finally, a numerical simulation example is provided to illustrate the optimization model and its algorithm. Results show that, (1) the shortest route is not necessarily the route that consumes the least energy, (2) the departure time influences the vehicle fuel consumption and CO2 emissions and the optimal departure time saves on fuel consumption and reduces CO2 emissions by up to 5.4%, and (3) extra driver wages have significant effects on routing and departure time slot decisions. PMID:29466370

Joint optimization of green vehicle scheduling and routing problem with time-varying speeds.

PubMed

Zhang, Dezhi; Wang, Xin; Li, Shuangyan; Ni, Nan; Zhang, Zhuo

2018-01-01

Based on an analysis of the congestion effect and changes in the speed of vehicle flow during morning and evening peaks in a large- or medium-sized city, the piecewise function is used to capture the rules of the time-varying speed of vehicles, which are very important in modelling their fuel consumption and CO2 emission. A joint optimization model of the green vehicle scheduling and routing problem with time-varying speeds is presented in this study. Extra wages during nonworking periods and soft time-window constraints are considered. A heuristic algorithm based on the adaptive large neighborhood search algorithm is also presented. Finally, a numerical simulation example is provided to illustrate the optimization model and its algorithm. Results show that, (1) the shortest route is not necessarily the route that consumes the least energy, (2) the departure time influences the vehicle fuel consumption and CO2 emissions and the optimal departure time saves on fuel consumption and reduces CO2 emissions by up to 5.4%, and (3) extra driver wages have significant effects on routing and departure time slot decisions.

Advances in Patch-Based Adaptive Mesh Refinement Scalability

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

Gunney, Brian T.N.; Anderson, Robert W.

Patch-based structured adaptive mesh refinement (SAMR) is widely used for high-resolution simu- lations. Combined with modern supercomputers, it could provide simulations of unprecedented size and resolution. A persistent challenge for this com- bination has been managing dynamically adaptive meshes on more and more MPI tasks. The dis- tributed mesh management scheme in SAMRAI has made some progress SAMR scalability, but early al- gorithms still had trouble scaling past the regime of 105 MPI tasks. This work provides two critical SAMR regridding algorithms, which are integrated into that scheme to ensure efficiency of the whole. The clustering algorithm is an extensionmore » of the tile- clustering approach, making it more flexible and efficient in both clustering and parallelism. The partitioner is a new algorithm designed to prevent the network congestion experienced by its prede- cessor. We evaluated performance using weak- and strong-scaling benchmarks designed to be difficult for dynamic adaptivity. Results show good scaling on up to 1.5M cores and 2M MPI tasks. Detailed timing diagnostics suggest scaling would continue well past that.« less

Multi-Objective Differential Evolution for Voltage Security Constrained Optimal Power Flow in Deregulated Power Systems

NASA Astrophysics Data System (ADS)

Roselyn, J. Preetha; Devaraj, D.; Dash, Subhransu Sekhar

2013-11-01

Voltage stability is an important issue in the planning and operation of deregulated power systems. The voltage stability problems is a most challenging one for the system operators in deregulated power systems because of the intense use of transmission line capabilities and poor regulation in market environment. This article addresses the congestion management problem avoiding offline transmission capacity limits related to voltage stability by considering Voltage Security Constrained Optimal Power Flow (VSCOPF) problem in deregulated environment. This article presents the application of Multi Objective Differential Evolution (MODE) algorithm to solve the VSCOPF problem in new competitive power systems. The maximum of L-index of the load buses is taken as the indicator of voltage stability and is incorporated in the Optimal Power Flow (OPF) problem. The proposed method in hybrid power market which also gives solutions to voltage stability problems by considering the generation rescheduling cost and load shedding cost which relieves the congestion problem in deregulated environment. The buses for load shedding are selected based on the minimum eigen value of Jacobian with respect to the load shed. In the proposed approach, real power settings of generators in base case and contingency cases, generator bus voltage magnitudes, real and reactive power demands of selected load buses using sensitivity analysis are taken as the control variables and are represented as the combination of floating point numbers and integers. DE/randSF/1/bin strategy scheme of differential evolution with self-tuned parameter which employs binomial crossover and difference vector based mutation is used for the VSCOPF problem. A fuzzy based mechanism is employed to get the best compromise solution from the pareto front to aid the decision maker. The proposed VSCOPF planning model is implemented on IEEE 30-bus system, IEEE 57 bus practical system and IEEE 118 bus system. The pareto optimal front obtained from MODE is compared with reference pareto front and the best compromise solution for all the cases are obtained from fuzzy decision making strategy. The performance measures of proposed MODE in two test systems are calculated using suitable performance metrices. The simulation results show that the proposed approach provides considerable improvement in the congestion management by generation rescheduling and load shedding while enhancing the voltage stability in deregulated power system.

Improving Explicit Congestion Notification with the Mark-Front Strategy

NASA Technical Reports Server (NTRS)

Liu, Chunlei; Jain, Raj

2001-01-01

Delivering congestion signals is essential to the performance of networks. Current TCP/IP networks use packet losses to signal congestion. Packet losses not only reduces TCP performance, but also adds large delay. Explicit Congestion Notification (ECN) delivers a faster indication of congestion and has better performance. However, current ECN implementations mark the packet from the tail of the queue. In this paper, we propose the mark-front strategy to send an even faster congestion signal. We show that mark-front strategy reduces buffer size requirement, improves link efficiency and provides better fairness among users. Simulation results that verify our analysis are also presented.

23 CFR 971.214 - Federal lands congestion management system (CMS).

Code of Federal Regulations, 2011 CFR

2011-04-01

... congestion management strategies; (v) Determine methods to monitor and evaluate the performance of the multi... Federal lands congestion management system (CMS). (a) For purposes of this section, congestion means the... for the transportation systems providing access to and within National Forests, as appropriate, that...

23 CFR 970.214 - Federal lands congestion management system (CMS).

Code of Federal Regulations, 2014 CFR

2014-04-01

... 23 Highways 1 2014-04-01 2014-04-01 false Federal lands congestion management system (CMS). 970... LANDS HIGHWAYS NATIONAL PARK SERVICE MANAGEMENT SYSTEMS National Park Service Management Systems § 970.214 Federal lands congestion management system (CMS). (a) For purposes of this section, congestion...

14 CFR 93.31 - Minimum usage requirement.

Code of Federal Regulations, 2011 CFR

2011-01-01

... operating Carrier used for air traffic control communications, scheduled time of operation, origin airport...) AIR TRAFFIC AND GENERAL OPERATING RULES SPECIAL AIR TRAFFIC RULES Congestion and Delay Reduction at... shall identify any Common Ownership or control of, by, or with any other carrier. A senior official of...

14 CFR 93.31 - Minimum usage requirement.

Code of Federal Regulations, 2010 CFR

2010-01-01

... operating Carrier used for air traffic control communications, scheduled time of operation, origin airport...) AIR TRAFFIC AND GENERAL OPERATING RULES SPECIAL AIR TRAFFIC RULES Congestion and Delay Reduction at... shall identify any Common Ownership or control of, by, or with any other carrier. A senior official of...

Disease management produces limited quality-of-life improvements in patients with congestive heart failure: evidence from a randomized trial in community-dwelling patients.

PubMed

Smith, Brad; Forkner, Emma; Zaslow, Barbara; Krasuski, Richard A; Stajduhar, Karl; Kwan, Michael; Ellis, Robert; Galbreath, Autumn Dawn; Freeman, Gregory L

2005-11-01

Disease management programs are reported to improve clinical and quality-of-life outcomes while simultaneously lowering healthcare costs. To examine the effectiveness of disease management in improving health-related quality of life (HRQL) among patients with heart failure beyond 12 months. A total of 1069 community-dwelling patients 18 years and older in South Texas with echocardiographic evidence of congestive heart failure were randomly assigned to disease management, augmented disease management, and control groups. They were followed up 18 months. Patients in the control group received usual care. Patients in the intervention groups were assigned a registered nurse as a disease manager who performed telephonic patient education and medication management. Health-related quality-of-life data (based on the Medical Outcomes Study 36-Item Short-Form Health Survey [SF-36]) were collected 4 times, at 6-month intervals. Disease management has a limited effect on HRQL. Analysis of the SF-36 health transition measure showed a positive effect of the intervention on self-reported improvement in health at 6 months and at 12 months (P = .04 and P = .004, respectively). However, no effect of disease management was observed across any of the SF-36 components. Women and patients with diastolic heart failure had poorer HRQL scores. Participation in disease management has little effect on HRQL outcomes in congestive heart failure. Beneficial effects on the SF-36 scale scores seen at 6 and 12 months were not sustained. Therefore, it is unclear whether disease management can provide long-term improvement in HRQL for patients with congestive heart failure.

Gastric Bypass Surgery Produces a Durable Reduction in Cardiovascular Disease Risk Factors and Reduces the Long-Term Risks of Congestive Heart Failure.

PubMed

Benotti, Peter N; Wood, G Craig; Carey, David J; Mehra, Vishal C; Mirshahi, Tooraj; Lent, Michelle R; Petrick, Anthony T; Still, Christopher; Gerhard, Glenn S; Hirsch, Annemarie G

2017-05-23

Obesity and its association with reduced life expectancy are well established, with cardiovascular disease as one of the major causes of fatality. Metabolic surgery is a powerful intervention for severe obesity, resulting in improvement in comorbid diseases and in cardiovascular risk factors. This study investigates the relationship between metabolic surgery and long-term cardiovascular events. A cohort of Roux-en-Y gastric bypass surgery (RYGB) patients was tightly matched by age, body mass index, sex, Framingham Risk Score, smoking history, use of antihypertension medication, diabetes mellitus status, and calendar year with a concurrent cohort of nonoperated control patients. The primary study end points of major cardiovascular events (myocardial infarction, stroke, and congestive heart failure) were evaluated using Cox regression. Secondary end points of longitudinal cardiovascular risk factors were evaluated using repeated-measures regression. The RYGB and matched controls (N=1724 in each cohort) were followed for up to 12 years after surgery (overall median of 6.3 years). Kaplan-Meier analysis revealed a statistically significant reduction in incident major composite cardiovascular events ( P =0.017) and congestive heart failure (0.0077) for the RYGB cohort. Adjusted Cox regression models confirmed the reductions in severe composite cardiovascular events in the RYGB cohort (hazard ratio=0.58, 95% CI=0.42-0.82). Improvements of cardiovascular risk factors (eg, 10-year cardiovascular risk score, total cholesterol, high-density lipoprotein, systolic blood pressure, and diabetes mellitus) were observed within the RYGB cohort after surgery. Gastric bypass is associated with a reduced risk of major cardiovascular events and the development of congestive heart failure. © 2017 The Authors and Geisinger Clinic. Published on behalf of the American Heart Association, Inc., by Wiley.

23 CFR 450.320 - Congestion management process in transportation management areas.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 23 Highways 1 2014-04-01 2014-04-01 false Congestion management process in transportation... Programming § 450.320 Congestion management process in transportation management areas. (a) The transportation planning process in a TMA shall address congestion management through a process that provides for safe and...

23 CFR 450.320 - Congestion management process in transportation management areas.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 23 Highways 1 2011-04-01 2011-04-01 false Congestion management process in transportation... Programming § 450.320 Congestion management process in transportation management areas. (a) The transportation planning process in a TMA shall address congestion management through a process that provides for safe and...

23 CFR 450.320 - Congestion management process in transportation management areas.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 23 Highways 1 2013-04-01 2013-04-01 false Congestion management process in transportation... Programming § 450.320 Congestion management process in transportation management areas. (a) The transportation planning process in a TMA shall address congestion management through a process that provides for safe and...

76 FR 75875 - Plan for Conduct of 2012 Electric Transmission Congestion Study

Federal Register 2010, 2011, 2012, 2013, 2014

2011-12-05

... DEPARTMENT OF ENERGY Plan for Conduct of 2012 Electric Transmission Congestion Study AGENCY... preparation of a study of electric transmission congestion pursuant to section 216(a)(1) of the Federal Power...-register at this Web site: http://energy.gov/oe/congestion-study-2012 . [[Page 75876

Traveller Information System for Heterogeneous Traffic Condition: A Case Study in Thiruvananthapuram City, India

NASA Astrophysics Data System (ADS)

Satyakumar, M.; Anil, R.; Sreeja, G. S.

2017-12-01

Traffic in Kerala has been growing at a rate of 10-11% every year, resulting severe congestion especially in urban areas. Because of the limitation of spaces it is not always possible to construct new roads. Road users rely on travel time information for journey planning and route choice decisions, while road system managers are increasingly viewing travel time as an important network performance indicator. More recently Advanced Traveler Information Systems (ATIS) are being developed to provide real-time information to roadway users. For ATIS various methodologies have been developed for dynamic travel time prediction. For this work the Kalman Filter Algorithm was selected for dynamic travel time prediction of different modes. The travel time data collected using handheld GPS device were used for prediction. Congestion Index were calculated and Range of CI values were determined according to the percentage speed drop. After prediction using Kalman Filter, the predicted values along with the GPS data was integrated to GIS and using Network Analysis of ArcGIS the offline route navigation guide was prepared. Using this database a program for route navigation based on travel time was developed. This system will help the travelers with pre-trip information.

Improved routing strategy based on gravitational field theory

NASA Astrophysics Data System (ADS)

Song, Hai-Quan; Guo, Jin

2015-10-01

Routing and path selection are crucial for many communication and logistic applications. We study the interaction between nodes and packets and establish a simple model for describing the attraction of the node to the packet in transmission process by using the gravitational field theory, considering the real and potential congestion of the nodes. On the basis of this model, we propose a gravitational field routing strategy that considers the attractions of all of the nodes on the travel path to the packet. In order to illustrate the efficiency of proposed routing algorithm, we introduce the order parameter to measure the throughput of the network by the critical value of phase transition from a free flow phase to a congested phase, and study the distribution of betweenness centrality and traffic jam. Simulations show that, compared with the shortest path routing strategy, the gravitational field routing strategy considerably enhances the throughput of the network and balances the traffic load, and nearly all of the nodes are used efficiently. Project supported by the Technology and Development Research Project of China Railway Corporation (Grant No. 2012X007-D) and the Key Program of Technology and Development Research Foundation of China Railway Corporation (Grant No. 2012X003-A).

TreeMAC: Localized TDMA MAC protocol for real-time high-data-rate sensor networks

USGS Publications Warehouse

Song, W.-Z.; Huang, R.; Shirazi, B.; Husent, R.L.

2009-01-01

Earlier sensor network MAC protocols focus on energy conservation in low-duty cycle applications, while some recent applications involve real-time high-data-rate signals. This motivates us to design an innovative localized TDMA MAC protocol to achieve high throughput and low congestion in data collection sensor networks, besides energy conservation. TreeMAC divides a time cycle into frames and frame into slots. Parent determines children's frame assigmnent based on their relative bandwidth demand, and each node calculates its own slot assignment based on its hop-count to the sink. This innovative 2-dimensional frame-slot assignment algorithm has the following nice theory properties. Firstly, given any node, at any time slot, there is at most one active sender in its neighborhood (includ ing itself). Secondly, the packet scheduling with TreelMAC is bufferless, which therefore minimizes the probability of network congestion. Thirdly, the data throughput to gateway is at least 1/3 of the optimum assuming reliable links. Our experiments on a 24 node test bed demonstrate that TreeMAC protocol significantly improves network throughput and energy efficiency, by comparing to the TinyOS's default CSMA MAC protocol and a recent TDMA MAC protocol Funneling-MAC[8]. ?? 2009 IEEE.

Optimization of BEV Charging Strategy

NASA Astrophysics Data System (ADS)

Ji, Wei

This paper presents different approaches to optimize fast charging and workplace charging strategy of battery electric vehicle (BEV) drivers. For the fast charging analysis, a rule-based model was built to simulate BEV charging behavior. Monte Carlo analysis was performed to explore to the potential range of congestion at fast charging stations which could be more than four hours at the most crowded stations. Genetic algorithm was performed to explore the theoretical minimum waiting time at fast charging stations, and it can decrease the waiting time at the most crowded stations to be shorter than one hour. A deterministic approach was proposed as a feasible suggestion that people should consider to take fast charging when the state of charge is approaching 40 miles. This suggestion is hoped to help to minimize potential congestion at fast charging stations. For the workplace charging analysis, scenario analysis was performed to simulate temporal distribution of charging demand under different workplace charging strategies. It was found that if BEV drivers charge as much as possible and as late as possible at workplace, it could increase the utility of solar-generated electricity while relieve grid stress of extra intensive electricity demand at night caused by charging electric vehicles at home.

On-board closed-loop congestion control for satellite based packet switching networks

NASA Technical Reports Server (NTRS)

Chu, Pong P.; Ivancic, William D.; Kim, Heechul

1993-01-01

NASA LeRC is currently investigating a satellite architecture that incorporates on-board packet switching capability. Because of the statistical nature of packet switching, arrival traffic may fluctuate and thus it is necessary to integrate congestion control mechanism as part of the on-board processing unit. This study focuses on the closed-loop reactive control. We investigate the impact of the long propagation delay on the performance and propose a scheme to overcome the problem. The scheme uses a global feedback signal to regulate the packet arrival rate of ground stations. In this scheme, the satellite continuously broadcasts the status of its output buffer and the ground stations respond by selectively discarding packets or by tagging the excessive packets as low-priority. The two schemes are evaluated by theoretical queuing analysis and simulation. The former is used to analyze the simplified model and to determine the basic trends and bounds, and the later is used to assess the performance of a more realistic system and to evaluate the effectiveness of more sophisticated control schemes. The results show that the long propagation delay makes the closed-loop congestion control less responsive. The broadcasted information can only be used to extract statistical information. The discarding scheme needs carefully-chosen status information and reduction function, and normally requires a significant amount of ground discarding to reduce the on-board packet loss probability. The tagging scheme is more effective since it tolerates more uncertainties and allows a larger margin of error in status information. It can protect the high-priority packets from excessive loss and fully utilize the downlink bandwidth at the same time.

[A prospective multicenter randomized controlled clinical study on the efficacy and safety of Guaifenesin compound pseudoephedrine hydrochloride oral solution].

PubMed

Lu, Quan

2010-03-01

To evaluate efficacy and safety of Guaifenesin compound pseudoephedrine hydrochloride oral solution for the treatment of cough, expectoration, nasal congestion and runny nose in children. This was a prospective multicenter randomized single-blind, parallel-controlled clinical study. A total of 10 centers participated in this study, the actual number of cases in line with the program was 412, of whom 205 cases in trial group were treated with Guaifenesin compound pseudoephedrine hydrochloride oral solution, and 207 cases in control group with ambroxol hydrochloride oral solution, treatment of both groups persisted for 7 days. The improvement rate of each single symptom and the combined symptoms and the overall effective rate were compared between the two groups. The adverse drug reactions and compliance were assessed as well. The treatment of both groups showed efficacy. Except sputum stickiness, the improvement of all symptoms in trial group was superior to that in the control group on the 3rd day after treatment (P < 0.05) and except nasal congestion, the efficacy in all the other symptoms of trial group was better than that in the control group as well on the 7th day (P < 0.01). The improvement rate for combined symptoms of Guaifenesin compound pseudoephedrine hydrochloride oral solution was 82.9% and the overall efficacy rate was 89.3%. Guaifenesin compound Pseudoephedrine hydrochloride oral solution had higher compliance and its adverse event rate was merely 0.92%. Guaifenesin compound pseudoephedrine hydrochloride oral solution showed significant efficacy and safety in children for treatment of cough, expectoration, nasal congestion and runny nose caused by common cold or acute tracheobronchitis.

Effects of intranasal xylometazoline, alone or in combination with ipratropium, in patients with common cold.

PubMed

Eccles, Ronald; Martensson, Kaj; Chen, Shirley C

2010-04-01

Common cold is one of the most prevalent conditions that family doctors encounter. One of the first symptoms to occur is nasal congestion, which can have a negative impact on daily life and prompts many patients to seek treatment for relief. Xylometazoline nasal spray (Otrivin*) is a topical decongestant that has been used successfully for many years and is generally recognized as an effective and safe therapy. However, most studies have investigated its clinical efficacy in healthy patients and few have included patients with common cold. To review the published clinical efficacy and safety of xylometazoline alone and in combination in the management of nasal congestion in patients with common cold. Literature searches of PubMed and the Cochrane Library were conducted to obtain published open or blinded, randomized, placebo- or active-controlled studies on the use of xylometazoline hydrochloride for the symptomatic relief of nasal congestion in patients with common cold. Searches included papers published in English only, up to September 2009. Despite the small number of studies identified in common cold (n = 4), as per search criteria defined, intranasal xylometazoline quickly and effectively relieved nasal congestion. When used alone, xylometazoline had a clinically relevant decongestant effect that was significantly superior for up to 10 hours compared with placebo. The superior decongestant effect with xylometazoline led to high patient satisfaction with treatment. When used in combination with ipratropium bromide, nasal congestion and rhinorrhoea were treated simultaneously, leading to significantly higher patient general impression scores compared with either agent used alone. Xylometazoline was well tolerated, with generally mild to moderate nasal-related side effects (e.g. epistaxis in 3.4% of patients, and blood-tinged mucus in 10-26% of patients) that were easily resolved; the most frequently reported non-nasal AEs were headache (3.4%) and period pain (10.3%); no cases of sedation were reported. As expected, no rhinitis medicamentosa or rebound congestion was noted with short-term use (<10 days). No clinically important differences in ciliary motility and mucociliary clearance were observed. Xylometazoline does not result in sympathomimetic systemic side effects seen with oral decongestants (e.g. pseudoephedrine, phenylephrine). The few studies available in common cold suggest that intranasal xylometazoline provides fast and effective relief of nasal congestion and is well tolerated. When xylometazoline is used in combination with ipratropium, patients with common cold experience the additive benefit of nasal congestion and rhinorrhoea being treated simultaneously.

Characterization of Visual Scanning Patterns in Air Traffic Control

PubMed Central

McClung, Sarah N.; Kang, Ziho

2016-01-01

Characterization of air traffic controllers' (ATCs') visual scanning strategies is a challenging issue due to the dynamic movement of multiple aircraft and increasing complexity of scanpaths (order of eye fixations and saccades) over time. Additionally, terminologies and methods are lacking to accurately characterize the eye tracking data into simplified visual scanning strategies linguistically expressed by ATCs. As an intermediate step to automate the characterization classification process, we (1) defined and developed new concepts to systematically filter complex visual scanpaths into simpler and more manageable forms and (2) developed procedures to map visual scanpaths with linguistic inputs to reduce the human judgement bias during interrater agreement. The developed concepts and procedures were applied to investigating the visual scanpaths of expert ATCs using scenarios with different aircraft congestion levels. Furthermore, oculomotor trends were analyzed to identify the influence of aircraft congestion on scan time and number of comparisons among aircraft. The findings show that (1) the scanpaths filtered at the highest intensity led to more consistent mapping with the ATCs' linguistic inputs, (2) the pattern classification occurrences differed between scenarios, and (3) increasing aircraft congestion caused increased scan times and aircraft pairwise comparisons. The results provide a foundation for better characterizing complex scanpaths in a dynamic task and automating the analysis process. PMID:27239190

Living on the Edge of Stagnant Water: An Assessment of Environmental Impacts of Construction-Phase Drainage Congestion Along Dhaka City Flood Control Embankment, Bangladesh

NASA Astrophysics Data System (ADS)

Rasid, Harun; Mallsk, Azim U.

1996-01-01

Environmental impacts of the construction-phase drainage congestion along the Dhaka City Flood Control Embankment were assessed by a pilot questionnaire survey (in 1991) among the target population adjacent to the embankment. The results of the survey indicated that, despite significant alleviation of river flooding, the majority of the respondents experienced a new type of flood problem in the form of stagnant water inside the embankment, immediately following its construction. Not only had this stagnant water flooded and damaged their property, it had exposed them to a number of other environmental problems, such as accumulation of municipal sewage, foul odors, mosquitoes, and growth of water hyacinth. The study found that the respondents’ assessments of these environmental problems differed significantly according to the magnitude of the impact of stagnant water upon two subgroups within the target population. A postsurvey follow-up in 1994 indicated that this problem of drainage congestion had largely been alleviated by completing the construction of a number of drainage regulators. The study concludes by stressing the importance of synchronizing the construction of drainage structures with that of the embankment systems and by underlining policy implications for flood-vulnerable land use adjacent to embankments.

Characterization of Visual Scanning Patterns in Air Traffic Control.

PubMed

McClung, Sarah N; Kang, Ziho

2016-01-01

Characterization of air traffic controllers' (ATCs') visual scanning strategies is a challenging issue due to the dynamic movement of multiple aircraft and increasing complexity of scanpaths (order of eye fixations and saccades) over time. Additionally, terminologies and methods are lacking to accurately characterize the eye tracking data into simplified visual scanning strategies linguistically expressed by ATCs. As an intermediate step to automate the characterization classification process, we (1) defined and developed new concepts to systematically filter complex visual scanpaths into simpler and more manageable forms and (2) developed procedures to map visual scanpaths with linguistic inputs to reduce the human judgement bias during interrater agreement. The developed concepts and procedures were applied to investigating the visual scanpaths of expert ATCs using scenarios with different aircraft congestion levels. Furthermore, oculomotor trends were analyzed to identify the influence of aircraft congestion on scan time and number of comparisons among aircraft. The findings show that (1) the scanpaths filtered at the highest intensity led to more consistent mapping with the ATCs' linguistic inputs, (2) the pattern classification occurrences differed between scenarios, and (3) increasing aircraft congestion caused increased scan times and aircraft pairwise comparisons. The results provide a foundation for better characterizing complex scanpaths in a dynamic task and automating the analysis process.

A research of the community’s opening to the outside world

NASA Astrophysics Data System (ADS)

Xu, Lan; Liu, Xiangzhuo

2017-03-01

Closed residential areas, called community, the traffic network and result in various degrees of traffic congestion such as amputating, dead ends and T-shaped roads. In order to reveal the mechanism of the congestion, establish an effective evaluation index system and finally provide theoretical basis for the study of traffic congestion, we have done researches on factors for traffic congestion and have established a scientific evaluation index system combining experiences home and abroad, based on domestic congestion status. Firstly, we analyse the traffic network as the entry point, and then establish the evaluation model of road capacity with the method of AHP index system. Secondly, we divide the condition of urban congestion into 5 levels from congestion to smoothness. Besides, with VISSIM software, simulations about traffic capacity before and after community opening are carried out. Finally, we provide forward reasonable suggestions upon the combination of models and reality.

Design and Evaluation of a Dynamic Programming Flight Routing Algorithm Using the Convective Weather Avoidance Model

NASA Technical Reports Server (NTRS)

Ng, Hok K.; Grabbe, Shon; Mukherjee, Avijit

2010-01-01

The optimization of traffic flows in congested airspace with varying convective weather is a challenging problem. One approach is to generate shortest routes between origins and destinations while meeting airspace capacity constraint in the presence of uncertainties, such as weather and airspace demand. This study focuses on development of an optimal flight path search algorithm that optimizes national airspace system throughput and efficiency in the presence of uncertainties. The algorithm is based on dynamic programming and utilizes the predicted probability that an aircraft will deviate around convective weather. It is shown that the running time of the algorithm increases linearly with the total number of links between all stages. The optimal routes minimize a combination of fuel cost and expected cost of route deviation due to convective weather. They are considered as alternatives to the set of coded departure routes which are predefined by FAA to reroute pre-departure flights around weather or air traffic constraints. A formula, which calculates predicted probability of deviation from a given flight path, is also derived. The predicted probability of deviation is calculated for all path candidates. Routes with the best probability are selected as optimal. The predicted probability of deviation serves as a computable measure of reliability in pre-departure rerouting. The algorithm can also be extended to automatically adjust its design parameters to satisfy the desired level of reliability.

Information filtering in evolving online networks

NASA Astrophysics Data System (ADS)

Chen, Bo-Lun; Li, Fen-Fen; Zhang, Yong-Jun; Ma, Jia-Lin

2018-02-01

Recommender systems use the records of users' activities and profiles of both users and products to predict users' preferences in the future. Considerable works towards recommendation algorithms have been published to solve the problems such as accuracy, diversity, congestion, cold-start, novelty, coverage and so on. However, most of these research did not consider the temporal effects of the information included in the users' historical data. For example, the segmentation of the training set and test set was completely random, which was entirely different from the real scenario in recommender systems. More seriously, all the objects are treated as the same, regardless of the new, the popular or obsoleted products, so do the users. These data processing methods always lose useful information and mislead the understanding of the system's state. In this paper, we detailed analyzed the difference of the network structure between the traditional random division method and the temporal division method on two benchmark data sets, Netflix and MovieLens. Then three classical recommendation algorithms, Global Ranking method, Collaborative Filtering and Mass Diffusion method, were employed. The results show that all these algorithms became worse in all four key indicators, ranking score, precision, popularity and diversity, in the temporal scenario. Finally, we design a new recommendation algorithm based on both users' and objects' first appearance time in the system. Experimental results showed that the new algorithm can greatly improve the accuracy and other metrics.

Improved space object detection using short-exposure image data with daylight background.

PubMed

Becker, David; Cain, Stephen

2018-05-10

Space object detection is of great importance in the highly dependent yet competitive and congested space domain. The detection algorithms employed play a crucial role in fulfilling the detection component in the space situational awareness mission to detect, track, characterize, and catalog unknown space objects. Many current space detection algorithms use a matched filter or a spatial correlator on long-exposure data to make a detection decision at a single pixel point of a spatial image based on the assumption that the data follow a Gaussian distribution. Long-exposure imaging is critical to detection performance in these algorithms; however, for imaging under daylight conditions, it becomes necessary to create a long-exposure image as the sum of many short-exposure images. This paper explores the potential for increasing detection capabilities for small and dim space objects in a stack of short-exposure images dominated by a bright background. The algorithm proposed in this paper improves the traditional stack and average method of forming a long-exposure image by selectively removing short-exposure frames of data that do not positively contribute to the overall signal-to-noise ratio of the averaged image. The performance of the algorithm is compared to a traditional matched filter detector using data generated in MATLAB as well as laboratory-collected data. The results are illustrated on a receiver operating characteristic curve to highlight the increased probability of detection associated with the proposed algorithm.

Population Pharmacokinetics of Fentanyl in the Critically Ill

PubMed Central

Choi, Leena; Ferrell, Benjamin A; Vasilevskis, Eduard E; Pandharipande, Pratik P; Heltsley, Rebecca; Ely, E Wesley; Stein, C Michael; Girard, Timothy D

2016-01-01

Objective To characterize fentanyl population pharmacokinetics in patients with critical illness and identify patient characteristics associated with altered fentanyl concentrations. Design Prospective cohort study. Setting Medical and surgical ICUs in a large tertiary care hospital in the United States. Patients Patients with acute respiratory failure and/or shock who received fentanyl during the first five days of their ICU stay. Measurements and Main Results We collected clinical and hourly drug administration data and measured fentanyl concentrations in plasma collected once daily for up to five days after enrollment. Among 337 patients, the mean duration of infusion was 58 hours at a median rate of 100 µg/hr. Using a nonlinear mixed-effects model implemented by NONMEM, we found fentanyl pharmacokinetics were best described by a two-compartment model in which weight, severe liver disease, and congestive heart failure most affected fentanyl concentrations. For a patient population with a mean weight of 92 kg and no history of severe liver disease or congestive heart failure, the final model, which performed well in repeated 10-fold cross-validation, estimated total clearance (CL), intercompartmental clearance (Q), and volumes of distribution for the central (V1) and peripheral compartments (V2) to be 35 (95% confidence interval: 32 to 39) L/hr, 55 (42 to 68) L/hr, 203 (140 to 266) L, and 523 (428 to 618) L, respectively. Severity of illness was marginally associated with fentanyl pharmacokinetics but did not improve the model fit after liver and heart disease were included. Conclusions In this study, fentanyl pharmacokinetics during critical illness were strongly influenced by severe liver disease, congestive heart failure, and weight, factors that should be considered when dosing fentanyl in the ICU. Future studies are needed to determine if data-driven fentanyl dosing algorithms can improve outcomes for ICU patients. PMID:26491862

Pulmonary edema

MedlinePlus

... congestion; Lung water; Pulmonary congestion; Heart failure - pulmonary edema ... Pulmonary edema is often caused by congestive heart failure . When the heart is not able to pump efficiently, blood ...

Reflex tracheal contraction during pulmonary venous congestion in the dog.

PubMed Central

Kappagoda, C T; Man, G C; Ravi, K; Teo, K K

1988-01-01

1. The effect of pulmonary venous congestion on tracheal tone was studied in dogs anaesthetized with alpha-chloralose. Pulmonary venous congestion was produced by partial obstruction of the mitral valve to increase left atrial pressure by 10 mmHg. Tracheal tone was measured in vivo by an isometric force displacement method. 2. Tracheal tone increased by 6.3 +/- 0.3 g from a control level of 91.6 +/- 2.8 g when left atrial pressure was increased by 10.5 +/- 0.3 mmHg. This response was abolished by cooling the cervical vagi to 8 degrees C at a point caudal to the origin of the superior laryngeal nerves. Also, sectioning the superior laryngeal nerves abolished this increase in tracheal tone. 3. Afferent activity recorded from rapidly adapting receptors of the airways increased significantly during pulmonary venous congestion. This increase in activity was abolished by cooling the vagi caudal to the recording site to 8-9 degrees C. 4. Administration of propranolol (0.5 mg/kg) failed to abolish this increase in tracheal tone while atropine (3 mg/kg) did so. 5. Stimulation of left atrial receptors without an increase in left atrial pressure and stimulation of right atrial receptors with and without increases in right atrial pressure did not cause any change in tracheal tone. 6. It is suggested that pulmonary venous congestion is associated with a reflex increase in tracheal tone, the afferent limb of which is formed by pulmonary receptors discharging into myelinated fibres in the cervical vagi and the efferent limb by parasympathetic cholinergic fibres in the superior laryngeal nerves. The afferent receptors are likely to be the rapidly adapting receptors. This reflex may be of importance in the development of the respiratory symptoms associated with left ventricular failure. PMID:3236242

Evaluation of contralateral kidney, liver and lung after extracorporeal shock wave lithotripsy in rabbits.

PubMed

Senyucel, M F; Boybeyi, O; Ayva, S; Aslan, M K; Soyer, T; Demet, A I; Kısa, U; Basar, M; Cakmak, M A

2013-10-01

An experimental study was carried out to evaluate the effects of extracorporeal shock wave lithotripsy (ESWL) on contralateral kidney, liver and lung by histopathological and biochemical methods. Twelve New Zealand rabbits were allocated to two groups (n = 6). Tissues of control group (CG, n = 6) were harvested without any intervention. In ESWL group (EG), right kidneys were exposed to 3,000 shock waves at 14 kV energy using electro-hydraulic type ESWL device three times every other day. Both kidneys, liver, and right lobe of lung tissues in EG were harvested on seventh day. Kidneys were examined histopathologically for presence of glomerular and tubular injury, interstitial edema, congestion, inflammation and fibrosis. Livers were examined for hepatocyte vacuolization, congestion, portal inflammation and fibrosis. Lung tissues were examined for loss of normal structure, emphysema, interstitial congestion-edema, prominent alveolar septal vessels, interstitial inflammation, intra-alveolar hemorrhage, intraluminal hemorrhage, peribronchial edema, congestion, inflammation in bronchial wall and epithelial desquamation. Biochemical analysis of tissue samples was performed for oxidative injury markers. Histopathological evaluations revealed that tubular injury was found in both shocked and contralateral kidneys (p < 0.05). EG showed higher grades of portal fibrosis in liver and higher grades of peribronchial congestion in lung when compared to CG (p < 0.05). Biochemical evaluations of both kidneys showed that malondialdehyde levels were higher in EG than in CG (p < 0.05). ESWL causes histopathologic alterations both in shocked and contralateral kidneys. Extrarenal tissues such as liver and lung can be affected by shock waves histopathologically and oxidative injury of contralateral kidney may occur acutely after ESWL.

Home telemonitoring of vital signs--technical challenges and future directions.

PubMed

Celler, Branko G; Sparks, Ross S

2015-01-01

The telemonitoring of vital signs from the home is an essential element of telehealth services for the management of patients with chronic conditions, such as congestive heart failure (CHF), chronic obstructive pulmonary disease (COPD), diabetes, or poorly controlled hypertension. Telehealth is now being deployed widely in both rural and urban settings, and in this paper, we discuss the contribution made by biomedical instrumentation, user interfaces, and automated risk stratification algorithms in developing a clinical diagnostic quality longitudinal health record at home. We identify technical challenges in the acquisition of high-quality biometric signals from unsupervised patients at home, identify new technical solutions and user interfaces, and propose new measurement modalities and signal processing techniques for increasing the quality and value of vital signs monitoring at home. We also discuss use of vital signs data for the automated risk stratification of patients, so that clinical resources can be targeted to those most at risk of unscheduled admission to hospital. New research is also proposed to integrate primary care, hospital, personal genomic, and telehealth electronic health records, and apply predictive analytics and data mining for enhancing clinical decision support.

Lifelink: 3G-based mobile telemedicine system.

PubMed

Alis, Christian; del Rosario, Carlos; Buenaobra, Bernardino; Mar Blanca, Carlo

2009-04-01

Current wired telemedicine systems encounter difficulties when implemented in archipelagic developing countries because of the high cost of fixed infrastructure. In this research, we devised Lifelink, a mobile real-time telemonitoring and diagnostic facility to command and control remote medical devices through mobile phones. The whole process is phone-based, effectively freeing offsite medical specialists from stationary monitoring consoles and endowing the system with the potential to increase the number participating consultants. The electrocardiogram (ECG) readings are analyzed using a detrended fluctuation technique and classified into pathological cases using an unassisted K-means clustering algorithm. We analyzed 30 batches of 2-hour ECG signals taken from cardiac patients (20 males, 10 females, mean age 46.7 years) with pre-diagnosed pathologies. The method successfully categorized the 30 subjects without user intervention into the following cases: normal (at 86.7% accuracy), congestive heart failure (86.7%), and atrial fibrillation (80.0%). The synergy of mobile monitoring and fluctuation analysis presents a powerful platform to reach remote, underserved communities with poor or nonexistent wired communication structures. It is likely to be essential in the development of new mobile diagnostic and prognostic measures.

EVALUATION OF THE SCATS CONTROL SYSTEM

DOT National Transportation Integrated Search

2008-12-01

Increasing travel demand and lack of sufficient highway capacity are serious problems in most major metropolitan areas in the United States. Large metropolitan areas have been experiencing increased traffic congestion problems over the past several y...

Guidelines for the operation of variable message signs on state highways

DOT National Transportation Integrated Search

2004-06-01

A variable message sign (VMS) is a traffic control device whose message can be changed manually, electrically, mechanically, or electromechanically to provide motorists with information about traffic congestion, traffic crashes, maintenance operation...

Optimized active traffic management and speed harmonization in work zones.

DOT National Transportation Integrated Search

2014-01-01

Traffic and demand management are major strategies to control delay and congestion in : highway bottlenecks including work zones. The Federal Highway Administration (FHWA) : introduced innovative strategies, called Active Traffic and Demand Managemen...

Data link airline benefits study : national sector survey

DOT National Transportation Integrated Search

1994-05-11

Survey information includes interviews with Traffic Management Unit managers or : representatives from 19 air route traffic control centers across the nation : experiencing volume satuation and frequency congestion on a regular basis and : require as...

Operational Evaluatioin of Dynamic Weather Routes at American Airlines

NASA Technical Reports Server (NTRS)

McNally, David; Sheth, Kapil; Gong, Chester; Borchers, Paul; Osborne, Jeff; Keany, Desmond; Scott, Brennan; Smith, Steve; Sahlman, Scott; Lee, Chuhan;

Rate of change of heart size before congestive heart failure in dogs with mitral regurgitation.

PubMed

Lord, P; Hansson, K; Kvart, C; Häggström, J

2010-04-01

The objective of the study was to examine the changes in vertebral heart scale, and left atrial and ventricular dimensions before and at onset of congestive heart failure in cavalier King Charles spaniels with mitral regurgitation. Records and radiographs from 24 cavalier King Charles spaniels with mitral regurgitation were used. Vertebral heart scale (24 dogs), and left atrial dimension and left ventricular end diastolic and end systolic diameters (18 dogs) and their rate of increase were measured at intervals over years to the onset of congestive heart failure. They were plotted against time to onset of congestive heart failure. Dimensions and rates of change of all parameters were highest at onset of congestive heart failure, the difference between observed and chance outcome being highly significant using a two-tailed chi-square test (P<0.001). The left heart chambers increase in size rapidly only in the last year before the onset of congestive heart failure. Increasing left ventricular end systolic dimension is suggestive of myocardial failure before the onset of congestive heart failure. Rate of increase of heart dimensions may be a useful indicator of impending congestive heart failure.

Hyperkalaemia in the age of aldosterone antagonism.

PubMed

Chapagain, A; Ashman, N

2012-11-01

Hyperkalaemia is well recognized as a medical emergency. However, with the publication of trials showing benefit with renin-aldosterone axis suppression in heart failure, the epidemiology of patients presenting with hyperkalaemia has changed. The reported incidence of rate of serious hyperkalaemia (>6.0 mEq/l of potassium) ranges from 6 to 12% in patients on spironolactone with congestive cardiac failure (CCF). A rational choice of therapy based on present evidence is different from the traditionally used algorithm, given our understanding of the physiology relevant to this patient group. This article discusses the changing face of hyperkalaemia and the present evidence and discusses options in treatment of hyperkalaemia.

Predictive functional control for active queue management in congested TCP/IP networks.

PubMed

Bigdeli, N; Haeri, M

2009-01-01

Predictive functional control (PFC) as a new active queue management (AQM) method in dynamic TCP networks supporting explicit congestion notification (ECN) is proposed. The ability of the controller in handling system delay along with its simplicity and low computational load makes PFC a privileged AQM method in the high speed networks. Besides, considering the disturbance term (which represents model/process mismatches, external disturbances, and existing noise) in the control formulation adds some level of robustness into the PFC-AQM controller. This is an important and desired property in the control of dynamically-varying computer networks. In this paper, the controller is designed based on a small signal linearized fluid-flow model of the TCP/AQM networks. Then, closed-loop transfer function representation of the system is derived to analyze the robustness with respect to the network and controller parameters. The analytical as well as the packet-level ns-2 simulation results show the out-performance of the developed controller for both queue regulation and resource utilization. Fast response, low queue fluctuations (and consequently low delay jitter), high link utilization, good disturbance rejection, scalability, and low packet marking probability are other features of the developed method with respect to other well-known AQM methods such as RED, PI, and REM which are also simulated for comparison.

Effects of mental workload on physiological and subjective responses during traffic density monitoring: A field study.

PubMed

Fallahi, Majid; Motamedzade, Majid; Heidarimoghadam, Rashid; Soltanian, Ali Reza; Miyake, Shinji

2016-01-01

This study evaluated operators' mental workload while monitoring traffic density in a city traffic control center. To determine the mental workload, physiological signals (ECG, EMG) were recorded and the NASA-Task Load Index (TLX) was administered for 16 operators. The results showed that the operators experienced a larger mental workload during high traffic density than during low traffic density. The traffic control center stressors caused changes in heart rate variability features and EMG amplitude, although the average workload score was significantly higher in HTD conditions than in LTD conditions. The findings indicated that increasing traffic congestion had a significant effect on HR, RMSSD, SDNN, LF/HF ratio, and EMG amplitude. The results suggested that when operators' workload increases, their mental fatigue and stress level increase and their mental health deteriorate. Therefore, it maybe necessary to implement an ergonomic program to manage mental health. Furthermore, by evaluating mental workload, the traffic control center director can organize the center's traffic congestion operators to sustain the appropriate mental workload and improve traffic control management. Copyright © 2015 Elsevier Ltd and The Ergonomics Society. All rights reserved.

Intensive symptom control of opioid-refractory dyspnea in congestive heart failure: Role of milrinone in the palliative care unit.

PubMed

Silvestre, Julio; Montoya, Maria; Bruera, Eduardo; Elsayem, Ahmed

2015-12-01

We describe an exemplary case of congestive heart failure (CHF) symptoms controlled with milrinone. We also analyze the benefits and risks of milrinone administration in an unmonitored setting. We describe the case of a patient with refractory leukemia and end-stage CHF who developed severe dyspnea after discontinuation of milrinone. At that point, despite starting opioids, she had been severely dyspneic and anxious, requiring admission to the palliative care unit (PCU) for symptom control. After negotiation with hospital administrators, milrinone was administered in an unmonitored setting such as the PCU. A multidisciplinary team approach was also provided. Milrinone produced a dramatic improvement in the patient's symptom scores and performance status. The patient was eventually discharged to home hospice on a milrinone infusion with excellent symptom control. This case suggests that milrinone may be of benefit for short-term inpatient administration for dyspnea management, even in unmonitored settings and consequently during hospice in do-not-resuscitate (DNR) patients. This strategy may reduce costs and readmissions to the hospital related to end-stage CHF.

Fuzzy Traffic Control with Vehicle-to-Everything Communication.

PubMed

Salman, Muntaser A; Ozdemir, Suat; Celebi, Fatih V

2018-01-27

Traffic signal control (TSC) with vehicle-to everything (V2X) communication can be a very efficient solution to traffic congestion problem. Ratio of vehicles equipped with V2X communication capability in the traffic to the total number of vehicles (called penetration rate PR) is still low, thus V2X based TSC systems need to be supported by some other mechanisms. PR is the major factor that affects the quality of TSC process along with the evaluation interval. Quality of the TSC in each direction is a function of overall TSC quality of an intersection. Hence, quality evaluation of each direction should follow the evaluation of the overall intersection. Computational intelligence, more specifically swarm algorithm, has been recently used in this field in a European Framework Program FP7 supported project called COLOMBO. In this paper, using COLOMBO framework, further investigations have been done and two new methodologies using simple and fuzzy logic have been proposed. To evaluate the performance of our proposed methods, a comparison with COLOMBOs approach has been realized. The results reveal that TSC problem can be solved as a logical problem rather than an optimization problem. Performance of the proposed approaches is good enough to be suggested for future work under realistic scenarios even under low PR.

Fuzzy Traffic Control with Vehicle-to-Everything Communication

PubMed Central

Ozdemir, Suat; Celebi, Fatih V.

2018-01-01

Traffic signal control (TSC) with vehicle-to everything (V2X) communication can be a very efficient solution to traffic congestion problem. Ratio of vehicles equipped with V2X communication capability in the traffic to the total number of vehicles (called penetration rate PR) is still low, thus V2X based TSC systems need to be supported by some other mechanisms. PR is the major factor that affects the quality of TSC process along with the evaluation interval. Quality of the TSC in each direction is a function of overall TSC quality of an intersection. Hence, quality evaluation of each direction should follow the evaluation of the overall intersection. Computational intelligence, more specifically swarm algorithm, has been recently used in this field in a European Framework Program FP7 supported project called COLOMBO. In this paper, using COLOMBO framework, further investigations have been done and two new methodologies using simple and fuzzy logic have been proposed. To evaluate the performance of our proposed methods, a comparison with COLOMBOs approach has been realized. The results reveal that TSC problem can be solved as a logical problem rather than an optimization problem. Performance of the proposed approaches is good enough to be suggested for future work under realistic scenarios even under low PR. PMID:29382053

Intelligent traffic lights based on MATLAB

NASA Astrophysics Data System (ADS)

Nie, Ying

2018-04-01

In this paper, I describes the traffic lights system and it has some. Through analysis, I used MATLAB technology, transformed the camera photographs into digital signals. Than divided the road vehicle is into three methods: very congestion, congestion, a little congestion. Through the MCU programming, solved the different roads have different delay time, and Used this method, saving time and resources, so as to reduce road congestion.

Connected Vehicle Technologies for Efficient Urban Transportation

DOT National Transportation Integrated Search

2016-10-24

Connected vehicle technology is employed to optimize the vehicle's control system in real-time to reduce congestion, improve fuel economy, and reduce emissions. This project's goal was to develop a two-way communication system to upload vehicle data ...

Simulation and analysis of three congested weigh stations using Westa

DOT National Transportation Integrated Search

2001-01-01

A user-friendly model for personal computers, "Vehicle/Highway Performance Predictor," was developed to estimate fuel consumption and exhaust emissions related to modes of vehicle operations on highways of various configurations and traffic controls ...

Signal timing under saturated conditions

DOT National Transportation Integrated Search

2008-11-01

This report provides guidance to practitioners for strategies and tactics that will help mitigate the effects of congestion at traffic signals. The focus was on methods that made use of settings wtihin the local intersection controller rather than on...

Automation of Data Traffic Control on DSM Architecture

NASA Technical Reports Server (NTRS)

Frumkin, Michael; Jin, Hao-Qiang; Yan, Jerry

2001-01-01

The design of distributed shared memory (DSM) computers liberates users from the duty to distribute data across processors and allows for the incremental development of parallel programs using, for example, OpenMP or Java threads. DSM architecture greatly simplifies the development of parallel programs having good performance on a few processors. However, to achieve a good program scalability on DSM computers requires that the user understand data flow in the application and use various techniques to avoid data traffic congestions. In this paper we discuss a number of such techniques, including data blocking, data placement, data transposition and page size control and evaluate their efficiency on the NAS (NASA Advanced Supercomputing) Parallel Benchmarks. We also present a tool which automates the detection of constructs causing data congestions in Fortran array oriented codes and advises the user on code transformations for improving data traffic in the application.

A new casemix adjustment index for hospital mortality among patients with congestive heart failure.

PubMed

Polanczyk, C A; Rohde, L E; Philbin, E A; Di Salvo, T G

1998-10-01

Comparative analysis of hospital outcomes requires reliable adjustment for casemix. Although congestive heart failure is one of the most common indications for hospitalization, congestive heart failure casemix adjustment has not been widely studied. The purposes of this study were (1) to describe and validate a new congestive heart failure-specific casemix adjustment index to predict in-hospital mortality and (2) to compare its performance to the Charlson comorbidity index. Data from all 4,608 admissions to the Massachusetts General Hospital from January 1990 to July 1996 with a principal ICD-9-CM discharge diagnosis of congestive heart failure were evaluated. Massachusetts General Hospital patients were randomly divided in a derivation and a validation set. By logistic regression, odds ratios for in-hospital death were computed and weights were assigned to construct a new predictive index in the derivation set. The performance of the index was tested in an internal Massachusetts General Hospital validation set and in a non-Massachusetts General Hospital external validation set incorporating data from all 1995 New York state hospital discharges with a primary discharge diagnosis of congestive heart failure. Overall in-hospital mortality was 6.4%. Based on the new index, patients were assigned to six categories with incrementally increasing hospital mortality rates ranging from 0.5% to 31%. By logistic regression, "c" statistics of the congestive heart failure-specific index (0.83 and 0.78, derivation and validation set) were significantly superior to the Charlson index (0.66). Similar incrementally increasing hospital mortality rates were observed in the New York database with the congestive heart failure-specific index ("c" statistics 0.75). In an administrative database, this congestive heart failure-specific index may be a more adequate casemix adjustment tool to predict hospital mortality in patients hospitalized for congestive heart failure.

Rhode Island congestion management plan : executive summary

DOT National Transportation Integrated Search

1997-09-01

This document provides an overview of the Rhode Island Congestion Management System (CMS) program consisting of the following: Congestion Management System Plan; Incident Management Plan; and Intelligent Transportation System (ITS) Early Deployment P...

Technologies that enable congestion pricing : a primer

DOT National Transportation Integrated Search

2008-10-01

This volume explores transportation technologies that enable congestion pricing. This document considers the following: the functional processes for tolling and congestion pricing; what technologies there are to consider; how the technologies are app...

Better road congestion measures are needed

DOT National Transportation Integrated Search

2003-05-01

Road congestion is growing worse as demand : outstrips new roadway construction and other : efforts to increase traffic flows. : Better ways to measure congestion are needed to : effectively address the problem. : Actual measures of speeds an...

Income-based equity impacts of congestion pricing

DOT National Transportation Integrated Search

2008-12-01

This equity primer was produced to examine the impacts of congestion pricing on low-income groups, public opinion as expressed by various income groups, and ways to mitigate the equity impacts of congestion pricing

Income-based equity impacts of congestion pricing.

DOT National Transportation Integrated Search

2008-12-01

This equity primer was produced to examine the impacts of congestion pricing on low-income groups, public opinion as expressed by various income groups, and ways to mitigate the equity impacts of congestion pricing.

Liver congestion in heart failure contributes to inappropriately increased serum hepcidin despite anemia.

PubMed

Ohno, Yukako; Hanawa, Haruo; Jiao, Shuang; Hayashi, Yuka; Yoshida, Kaori; Suzuki, Tomoyasu; Kashimura, Takeshi; Obata, Hiroaki; Tanaka, Komei; Watanabe, Tohru; Minamino, Tohru

2015-01-01

Hepcidin is a key regulator of mammalian iron metabolism and mainly produced by the liver. Hepcidin excess causes iron deficiency and anemia by inhibiting iron absorption from the intestine and iron release from macrophage stores. Anemia is frequently complicated with heart failure. In heart failure patients, the most frequent histologic appearance of liver is congestion. However, it remains unclear whether liver congestion associated with heart failure influences hepcidin production, thereby contributing to anemia and functional iron deficiency. In this study, we investigated this relationship in clinical and basic studies. In clinical studies of consecutive heart failure patients (n = 320), anemia was a common comorbidity (41%). In heart failure patients without active infection and ongoing cancer (n = 30), log-serum hepcidin concentration of patients with liver congestion was higher than those without liver congestion (p = 0.0316). Moreover, in heart failure patients with liver congestion (n = 19), the anemia was associated with the higher serum hepcidin concentrations, which is a type of anemia characterized by induction of hepcidin. Subsequently, we produced a rat model of heart failure with liver congestion by injecting monocrotaline that causes pulmonary hypertension. The monocrotaline-treated rats displayed liver congestion with increase of hepcidin expression at 4 weeks after monocrotaline injection, followed by anemia and functional iron deficiency observed at 5 weeks. We conclude that liver congestion induces hepcidin production, which may result in anemia and functional iron deficiency in some patients with heart failure.

Green supply chain: Simulating road traffic congestion

NASA Astrophysics Data System (ADS)

Jalal, Muhammad Zulqarnain Hakim Abd; Nawawi, Mohd Kamal Mohd; Laailatul Hanim Mat Desa, Wan; Khalid, Ruzelan; Khalid Abduljabbar, Waleed; Ramli, Razamin

2017-09-01

With the increasing awareness of the consumers about environmental issues, businesses, households and governments increasingly want use green products and services which lead to green supply chain. This paper discusses a simulation study of a selected road traffic system that will contribute to the air pollution if in the congestion state. Road traffic congestion (RTC) can be caused by a temporary obstruction, a permanent capacity bottleneck in the network itself, and stochastic fluctuation in demand within a particular sector of the network, leading to spillback and queue propagation. A discrete-event simulation model is developed to represent the real traffic light control (TLC) system condition during peak hours. Certain performance measures such as average waiting time and queue length were measured using the simulation model. Existing system uses pre-set cycle time to control the light changes which is fixed time cycle. In this research, we test several other combination of pre-set cycle time with the objective to find the best system. In addition, we plan to use a combination of the pre-set cycle time and a proximity sensor which have the authority to manipulate the cycle time of the lights. The sensors work in such situation when the street seems to have less occupied vehicles, obviously it may not need a normal cycle for green light, and automatically change the cycle to street where vehicle is present.

[Diuretic therapy in heart failure].

PubMed

Trullàs, Joan Carles; Morales-Rull, José Luís; Formiga, Francesc

2014-02-20

Many of the primary clinical manifestations of heart failure (HF) are due to fluid retention, and treatments targeting congestion play a central role in HF management. Diuretic therapy remains the cornerstone of congestion treatment, and diuretics are prescribed to the majority of HF patients. Despite this ubiquitous use, there is limited evidence from prospective randomized studies to guide the use of diuretics. With the chronic use of diuretic and usually in advanced stages of HF, diuretics may fail to control salt and water retention. This review describes the mechanism of action of available diuretic classes, reviews their clinical use based on scientific evidence and discusses strategies to overcome diuretic resistance. Copyright © 2013 Elsevier España, S.L. All rights reserved.

Congestion Prediction Modeling for Quality of Service Improvement in Wireless Sensor Networks

PubMed Central

Lee, Ga-Won; Lee, Sung-Young; Huh, Eui-Nam

2014-01-01

Information technology (IT) is pushing ahead with drastic reforms of modern life for improvement of human welfare. Objects constitute “Information Networks” through smart, self-regulated information gathering that also recognizes and controls current information states in Wireless Sensor Networks (WSNs). Information observed from sensor networks in real-time is used to increase quality of life (QoL) in various industries and daily life. One of the key challenges of the WSNs is how to achieve lossless data transmission. Although nowadays sensor nodes have enhanced capacities, it is hard to assure lossless and reliable end-to-end data transmission in WSNs due to the unstable wireless links and low hard ware resources to satisfy high quality of service (QoS) requirements. We propose a node and path traffic prediction model to predict and minimize the congestion. This solution includes prediction of packet generation due to network congestion from both periodic and event data generation. Simulation using NS-2 and Matlab is used to demonstrate the effectiveness of the proposed solution. PMID:24784035

Cheyne-Stokes respiration in patients with congestive heart failure: causes and consequences.

PubMed

Lorenzi-Filho, Geraldo; Genta, Pedro R; Figueiredo, Adelaide C; Inoue, Daniel

2005-08-01

Cheyne-Stokes respiration is a form of periodic breathing in which central apneas and hypopneas alternate with periods of hyperventilation, producing a waxing and waning pattern of tidal volume. This review focuses on the causes and consequences of Cheyne-Stokes respiration in patients with congestive heart failure, in whom the prevalence is strikingly high and ranges from 30% to 50%. Several factors have been implicated in the genesis of Cheyne-Stokes respiration, including low cardiac output and recurrent hypoxia. The key pathophysiological mechanism triggering Cheyne-Stokes respiration is hyperventilation and low arterial CO2 (PaCO2) that when below the apneic threshold triggers a central apnea. Hyperventilation is associated with pulmonary congestion, and Cheyne-Stokes respiration is more prone to occur during sleep, when the respiratory system is mainly dependent on chemical control. It is associated with recurrent dips in oxygen saturation and arousals from sleep, with oscillations in blood pressure and heart rate, sympathetic activation and increased risk of ventricular tachycardia. Cheyne-Stokes respiration is an independent marker of poor prognosis and may participate in a vicious cycle, further stressing the failing heart.

Therapeutic Effects of Fermented Red Ginseng in Allergic Rhinitis: A Randomized, Double-Blind, Placebo-Controlled Study

PubMed Central

Jung, Jae-Woo; Ji, Geun-Eog; Park, Myeong-Soo; Song, Woo-Jung; Kim, Min-Hye; Kwon, Jae-Woo; Kim, Tae-Whan; Park, Heung-Woo; Cho, Sang-Heon; Min, Kyung-Up

2011-01-01

Purpose Allergic rhinitis is clinically defined as a disorder of the nose induced by IgE mediated inflammation after allergen exposure of the nasal mucosa. Many reports have stated that Panax ginseng and fermented red ginseng have anti-inflammatory effects, especially against Th2-type inflammation. This study was conducted to evaluate the therapeutic effects of fermented red ginseng in allergic rhinitis. Methods In this 4-week, double-blind, placebo-controlled study, 59 patients with persistent perennial allergic rhinitis were randomly divided into two groups: those receiving fermented red ginseng tablets (experimental group) and those receiving placebo (control group). The primary efficacy variable was the total nasal symptom score (TNSS; rhinorrhea, sneezing, itchy nose, and nasal congestion). Secondary efficacy variables were the Rhinitis Quality of Life (RQoL) score and skin reactivity to inhalant allergens, as determined by the skin prick test. Results There was no significant difference in the TNSS score and TNSS duration score between the experimental and placebo groups in weeks 1, 2, 3, or 4. For nasal congestion, fermented red ginseng was significantly effective (P<0.005), while placebo caused no change. The activity and emotion of RQoL improved markedly secondary to treatment with fermented red ginseng (P<0.05), while placebo caused no change. Additionally, fermented red ginseng reduced skin reactivity to sensitized perennial allergens (P<0.05). Fermented red ginseng was well tolerated. Conclusions Fermented red ginseng improved nasal congestion symptoms and RQoL in patients with perennial allergic rhinitis. PMID:21461249

Alternative performance measures for evaluating congestion.

DOT National Transportation Integrated Search

2004-04-01

This report summarizes the results of the work performed under the project Alternative Performance Measures for Evaluating : Congestion. The study first outlines existing approaches to looking at congestion. It then builds on the previous work in the...

Technologies that complement congestion pricing : a primer.

DOT National Transportation Integrated Search

2008-10-01

The purpose of this volume is to consider the technology options that are available to complement congestion-pricing approaches. This primer explores how technology broadens the success for congestion pricing by supporting the traveler's decision to ...

Multimodal and corridor applications of travel time reliability.

DOT National Transportation Integrated Search

2012-03-30

Congestion is all too familiar in Floridas cities. Traditionally, agencies have tried to mitigate recurring congestion by comparing demand and capacity during peak periods and alleviating bottlenecks. However, congestion is often due to nonrecurri...

Multimodal and corridor applications of travel time reliability : [summary].

DOT National Transportation Integrated Search

2012-01-01

Congestion is all too familiar in Floridas cities. Traditionally, agencies have tried to mitigate recurring congestion by comparing demand and capacity during peak periods and alleviating bottlenecks. However, congestion is often due to nonrecurri...

Statewide GIS mapping of recurring congestion corridors : final report.

DOT National Transportation Integrated Search

2009-07-01

Recurring congestion occurs when travel demand reaches or exceeds the available roadway : capacity. This project developed an interactive geographic information system (GIS) map of the : recurring congestion corridors (labeled herein as hotspots) in ...

Congestion pricing : a primer : overview

DOT National Transportation Integrated Search

2008-10-01

This Overview primer was produced to explain the concept of congestion pricing and its benefits, to present examples of congestion-pricing approaches implemented in the United States and abroad, and to briefly discuss federal-aid policy and programs ...

Local empathy provides global minimization of congestion in communication networks

NASA Astrophysics Data System (ADS)

Meloni, Sandro; Gómez-Gardeñes, Jesús

2010-11-01

We present a mechanism to avoid congestion in complex networks based on a local knowledge of traffic conditions and the ability of routers to self-coordinate their dynamical behavior. In particular, routers make use of local information about traffic conditions to either reject or accept information packets from their neighbors. We show that when nodes are only aware of their own congestion state they self-organize into a hierarchical configuration that delays remarkably the onset of congestion although leading to a sharp first-order-like congestion transition. We also consider the case when nodes are aware of the congestion state of their neighbors. In this case, we show that empathy between nodes is strongly beneficial to the overall performance of the system and it is possible to achieve larger values for the critical load together with a smooth, second-order-like, transition. Finally, we show how local empathy minimize the impact of congestion as much as global minimization. Therefore, here we present an outstanding example of how local dynamical rules can optimize the system’s functioning up to the levels reached using global knowledge.

Sample entropy applied to the analysis of synthetic time series and tachograms

NASA Astrophysics Data System (ADS)

Muñoz-Diosdado, A.; Gálvez-Coyt, G. G.; Solís-Montufar, E.

2017-01-01

Entropy is a method of non-linear analysis that allows an estimate of the irregularity of a system, however, there are different types of computational entropy that were considered and tested in order to obtain one that would give an index of signals complexity taking into account the data number of the analysed time series, the computational resources demanded by the method, and the accuracy of the calculation. An algorithm for the generation of fractal time-series with a certain value of β was used for the characterization of the different entropy algorithms. We obtained a significant variation for most of the algorithms in terms of the series size, which could result counterproductive for the study of real signals of different lengths. The chosen method was sample entropy, which shows great independence of the series size. With this method, time series of heart interbeat intervals or tachograms of healthy subjects and patients with congestive heart failure were analysed. The calculation of sample entropy was carried out for 24-hour tachograms and time subseries of 6-hours for sleepiness and wakefulness. The comparison between the two populations shows a significant difference that is accentuated when the patient is sleeping.

Traffic control for high occupancy vehicle facilities in Virginia.

DOT National Transportation Integrated Search

1998-04-01

High occupancy vehicle (HOV) facilities are an important tool in relieving the congestion that continues to build on many urban roadways. By moving more people in fewer vehicles, the existing infrastructure can be used more efficiently. Operating HOV...

Legal constraints to the research, development, and deployment of IVHS technology in the United States

DOT National Transportation Integrated Search

1993-03-31

Intelligent Vehicle Highway Systems (IVHS) are a diffuse : collection of automotive, communications, controls, traffic : management, and systems technologies that hold the potential to : improve highway safety, reduce traffic congestion, and improve ...

Atlanta congestion reduction demonstration : national evaluation report.

DOT National Transportation Integrated Search

2014-03-01

This document presents the final report on the national evaluation of the Atlanta Congestion Reduction Demonstration (CRD) under the United States Department of Transportation (U.S. DOT) CRD Program. The Atlanta CRD projects focus on reducing congest...

Modeling the effect of accessibility and congestion in location choice.

DOT National Transportation Integrated Search

2012-12-01

This study explores the relationship between accessibility and congestion, and their impacts on property values. Three research questions are addressed: (1) What is the relation between accessibility and congestion both regional and neighborhood leve...

Speed harmonization and peak-period shoulder use to manage urban freeway congestion.

DOT National Transportation Integrated Search

2009-10-01

Traffic congestion is an increasing problem in the nations urban areas, leading to personal inconvenience, : increased pollution, hampered economic productivity, and reduced quality of life. While traffic congestion tends : to continuously increas...

A toolbox for alleviating traffic congestion and enhancing mobility

DOT National Transportation Integrated Search

2012-06-01

This report presents the Tolling Data Test Plan for the national evaluation of the Los Angeles (LA) Congestion Reduction Demonstration (Metro ExpressLanes) under the United States Department of Transportation (U.S. DOT) Congestion Reduction Demonstra...

Determining queue and congestion in highway work zone bottlenecks.

DOT National Transportation Integrated Search

2011-03-11

Construction zones, though required for infrastructure maintenance, have become congestion choke points on most highway systems in the US. The congestion may create potentially unsafe driving conditions for approaching motorists that do not expect qu...

Determining Queue and Congestion in Highway Work Zone Bottlenecks

DOT National Transportation Integrated Search

2011-03-11

Construction zones, though required for infrastructure maintenance, have become congestion choke points on most highway systems in the US. The congestion may create potentially unsafe driving conditions for approaching motorists that do not expect qu...

Diagnosis and Treatment of Depression in Patients With Congestive Heart Failure: A Review of the Literature

PubMed Central

Stern, Theodore A.; Hebert, Kathy A.; Musselman, Dominique L.

2013-01-01

Context: Major depressive disorder (MDD) can be challenging to diagnose in patients with congestive heart failure, who often suffer from fatigue, insomnia, weight changes, and other neurovegetative symptoms that overlap with those of depression. Pathophysiologic mechanisms (eg, inflammation, autonomic nervous system dysfunction, cardiac arrhythmias, and altered platelet function) connect depression and congestive heart failure. Objective: We sought to review the prevalence, diagnosis, neurobiology, and treatment of depression associated with congestive heart failure. Data Sources: A search of all English-language articles between January 2003 and January 2013 was conducted using the search terms congestive heart failure and depression. Study Selection: We found 1,498 article abstracts and 19 articles (meta-analyses, systematic reviews, and original research articles) that were selected for inclusion, as they contained information about our focus on diagnosis, treatment, and pathophysiology of depression associated with congestive heart failure. The search was augmented with manual review of reference lists of articles from the initial search. Articles selected for review were determined by author consensus. Data Extraction: The prevalence, diagnosis, neurobiology, and treatment of depression associated with congestive heart failure were reviewed. Particular attention was paid to the safety, efficacy, and tolerability of antidepressant medications commonly used to treat depression and how their side-effect profiles impact the pathophysiology of congestive heart failure. Drug-drug interactions between antidepressant medications and medications used to treat congestive heart failure were examined. Results: MDD is highly prevalent in patients with congestive heart failure. Moreover, the prevalence and severity of depression correlate with the degree of cardiac dysfunction and development of congestive heart failure. Depression increases the risk of congestive heart failure, particularly in those patients with coronary artery disease , and is associated with a poorer quality of life, increased use of health care resources, more frequent adverse clinical events and hospitalizations, and twice the risk of mortality. Conclusions: At present, limited empirical data exist with regard to treatment of depression in the increasingly large population of patients with congestive heart failure. Evidence reveals that both psychotherapeutic treatment (eg, cognitive-behavioral therapy) and pharmacologic treatment (eg, use of the selective serotonin reuptake inhibitor sertraline) are safe and effective in reducing depression severity in patients with cardiovascular disease. Collaborative care programs featuring interventions that work to improve adherence to medical and psychiatric treatments improve both cardiovascular disease and depression outcomes. Depression rating scales such as the 9-item Patient Health Questionnaire should be used to monitor therapeutic efficacy. PMID:24392265

Major developments in the 2016 european guidelines for heart failure.

PubMed

Trullàs, J C; González-Franco, Á

2017-10-01

The European Society of Cardiology has recently published new guidelines on the diagnosis and treatment of acute and chronic heart failure (HF). This article aims to review these recommendations and their level of scientific evidence and to present the most innovative aspects. The most significant deviations from the 2012 edition are: 1) the introduction of the concept of HF with midrange LVEF (40-49%); 2) a new diagnostic algorithm for chronic HF, initially considering the clinical probability; 3) recommendations on preventing or delaying the apparition of HF; 4) indications for the use of the new sacubitril-valsartan compound, the first angiotensin receptor blocker and neprilysin inhibitor; 5) modification of indications for cardiac resynchronisation therapy; and 6) a new algorithm for a combined diagnostic and treatment strategy for acute HF based on the presence or absence of congestion and hypoperfusion. Copyright © 2017 Elsevier España, S.L.U. and Sociedad Española de Medicina Interna (SEMI). All rights reserved.

Using temporal detrending to observe the spatial correlation of traffic.

PubMed

Ermagun, Alireza; Chatterjee, Snigdhansu; Levinson, David

2017-01-01

This empirical study sheds light on the spatial correlation of traffic links under different traffic regimes. We mimic the behavior of real traffic by pinpointing the spatial correlation between 140 freeway traffic links in a major sub-network of the Minneapolis-St. Paul freeway system with a grid-like network topology. This topology enables us to juxtapose the positive and negative correlation between links, which has been overlooked in short-term traffic forecasting models. To accurately and reliably measure the correlation between traffic links, we develop an algorithm that eliminates temporal trends in three dimensions: (1) hourly dimension, (2) weekly dimension, and (3) system dimension for each link. The spatial correlation of traffic links exhibits a stronger negative correlation in rush hours, when congestion affects route choice. Although this correlation occurs mostly in parallel links, it is also observed upstream, where travelers receive information and are able to switch to substitute paths. Irrespective of the time-of-day and day-of-week, a strong positive correlation is witnessed between upstream and downstream links. This correlation is stronger in uncongested regimes, as traffic flow passes through consecutive links more quickly and there is no congestion effect to shift or stall traffic. The extracted spatial correlation structure can augment the accuracy of short-term traffic forecasting models.

Using temporal detrending to observe the spatial correlation of traffic

PubMed Central

2017-01-01

This empirical study sheds light on the spatial correlation of traffic links under different traffic regimes. We mimic the behavior of real traffic by pinpointing the spatial correlation between 140 freeway traffic links in a major sub-network of the Minneapolis—St. Paul freeway system with a grid-like network topology. This topology enables us to juxtapose the positive and negative correlation between links, which has been overlooked in short-term traffic forecasting models. To accurately and reliably measure the correlation between traffic links, we develop an algorithm that eliminates temporal trends in three dimensions: (1) hourly dimension, (2) weekly dimension, and (3) system dimension for each link. The spatial correlation of traffic links exhibits a stronger negative correlation in rush hours, when congestion affects route choice. Although this correlation occurs mostly in parallel links, it is also observed upstream, where travelers receive information and are able to switch to substitute paths. Irrespective of the time-of-day and day-of-week, a strong positive correlation is witnessed between upstream and downstream links. This correlation is stronger in uncongested regimes, as traffic flow passes through consecutive links more quickly and there is no congestion effect to shift or stall traffic. The extracted spatial correlation structure can augment the accuracy of short-term traffic forecasting models. PMID:28472093

Congestion game scheduling for virtual drug screening optimization

NASA Astrophysics Data System (ADS)

Nikitina, Natalia; Ivashko, Evgeny; Tchernykh, Andrei

2018-02-01

In virtual drug screening, the chemical diversity of hits is an important factor, along with their predicted activity. Moreover, interim results are of interest for directing the further research, and their diversity is also desirable. In this paper, we consider a problem of obtaining a diverse set of virtual screening hits in a short time. To this end, we propose a mathematical model of task scheduling for virtual drug screening in high-performance computational systems as a congestion game between computational nodes to find the equilibrium solutions for best balancing the number of interim hits with their chemical diversity. The model considers the heterogeneous environment with workload uncertainty, processing time uncertainty, and limited knowledge about the input dataset structure. We perform computational experiments and evaluate the performance of the developed approach considering organic molecules database GDB-9. The used set of molecules is rich enough to demonstrate the feasibility and practicability of proposed solutions. We compare the algorithm with two known heuristics used in practice and observe that game-based scheduling outperforms them by the hit discovery rate and chemical diversity at earlier steps. Based on these results, we use a social utility metric for assessing the efficiency of our equilibrium solutions and show that they reach greatest values.

Baroreflex Activation Therapy in Congestive Heart Failure: Novel Findings and Future Insights.

PubMed

Grassi, Guido; Brambilla, GianMaria; Pizzalla, Daniela Prata; Seravalle, Gino

2016-08-01

Congestive heart failure is characterized by hemodynamic and non-hemodynamic abnormalities, the latter including an activation of the sympathetic influences to the heart and peripheral circulation coupled with an impairment of baroreceptor control of autonomic function. Evidence has been provided that both these alterations are hallmark features of the disease with a specific relevance for the disease progression as well as for the development of life-threatening cardiac arrhythmias. In addition, a number of studies have documented in heart failure the adverse prognostic role of the sympathetic and baroreflex alterations, which both are regarded as major independent determinants of cardiovascular morbidity and mortality. This represents the pathophysiological and clinical background for the use of carotid baroreceptor activation therapy in the treatment of congestive heart failure. Promising data collected in experimental animal models of heart failure have supported the recent performance of pilot small-scale clinical studies, aimed at providing initial information in this area. The results of these studies demonstrated the clinical safety and efficacy of the intervention which has been tested in large-scale clinical studies. The present paper will critically review the background and main results of the published studies designed at defining the clinical impact of baroreflex activation therapy in congestive heart failure patients. Emphasis will be given to the strengths and limitations of such studies, which represent the background for the ongoing clinical trials testing the long-term effects of the device in heart failure patients.

Forecasting the clearance time of freeway accidents

DOT National Transportation Integrated Search

2002-01-01

Freeway congestion is a major and costly problem in many U.S. metropolitan areas. From a traveler's perspective, congestion has costs in terms of longer travel times and lost productivity. From the traffic manager's perspective, congestion causes a f...

The economic cost of traffic congestion in Florida.

DOT National Transportation Integrated Search

2010-08-01

Traffic congestion in the U.S. is bad and getting worse, and it is expensive. Appropriate solutions to this problem require appropriate information. A comprehensive and accurate analysis of congestion costs is a critical tool for planning and impleme...

Air quality assessment at a congested urban intersection

DOT National Transportation Integrated Search

2000-09-01

The deficient transportation system of Beirut results in significant economic losses for the city and causes severe traffic congestion in the urban areas. Proposals have been made for grade separations at some of the worst congested intersections. Th...

Impact of congestion on bus operations and costs.

DOT National Transportation Integrated Search

2003-10-01

Traffic congestion in Northern New Jersey imposes substantial operational and monetary penalty on bus service. The purpose of this project was to quantify the additional time and costs due to traffic congestion. A regression model was developed that ...

Mobility and the Costs of Congestion in New Jersey

DOT National Transportation Integrated Search

2000-02-01

This study measured quantifiable and qualitative impacts of congestion in New Jersey on mobility, the cost of transportation, and economic productivity. It addressed the impacts of congestion on both an individual level (impacts on an average travele...

Measuring non-recurrent congestion in small to medium sized urban areas.

DOT National Transportation Integrated Search

2013-05-01

Understanding the relative magnitudes of recurrent vs. non-recurrent congestion in an urban area is critical to the selection of proper countermeasures and the appropriate allocation of resources to address congestion problems. Small to medium sized ...

Estimating teat canal cross-sectional area to determine the effects of teat-end and mouthpiece chamber vacuum on teat congestion.

PubMed

Penry, J F; Upton, J; Mein, G A; Rasmussen, M D; Ohnstad, I; Thompson, P D; Reinemann, D J

2017-01-01

The primary objective of this experiment was to assess the effect of mouthpiece chamber vacuum on teat-end congestion. The secondary objective was to assess the interactive effects of mouthpiece chamber vacuum with teat-end vacuum and pulsation setting on teat-end congestion. The influence of system vacuum, pulsation settings, mouthpiece chamber vacuum, and teat-end vacuum on teat-end congestion were tested in a 2×2 factorial design. The low-risk conditions for teat-end congestion (TEL) were 40 kPa system vacuum (Vs) and 400-ms pulsation b-phase. The high-risk conditions for teat-end congestion (TEH) were 49 kPa Vs and 700-ms b-phase. The low-risk condition for teat-barrel congestion (TBL) was created by venting the liner mouthpiece chamber to atmosphere. In the high-risk condition for teat-barrel congestion (TBH) the mouthpiece chamber was connected to short milk tube vacuum. Eight cows (32 quarters) were used in the experiment conducted during 0400 h milkings. All cows received all treatments over the entire experimental period. Teatcups were removed after 150 s for all treatments to standardize the exposure period. Calculated teat canal cross-sectional area (CA) was used to assess congestion of teat tissue. The main effect of the teat-end treatment was a reduction in CA of 9.9% between TEL and TEH conditions, for both levels of teat-barrel congestion risk. The main effect of the teat-barrel treatment was remarkably similar, with a decrease of 9.7% in CA between TBL and TBH conditions for both levels of teat-end congestion risk. No interaction between treatments was detected, hence the main effects are additive. The most aggressive of the 4 treatment combinations (TEH plus TBH) had a CA estimate 20% smaller than for the most gentle treatment combination (TEL plus TBL). The conditions designed to impair circulation in the teat barrel also had a deleterious effect on circulation at the teat end. This experiment highlights the importance of elevated mouthpiece chamber vacuum on teat-end congestion and resultant decreases in CA. Copyright © 2017 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Medicinal Leech Therapy for Glans Penis Congestion After Primary Bladder Exstrophy-Epispadias Repair in an Infant: A Case Report.

PubMed

Wagenheim, Gavin N; Au, Jason; Gargollo, Patricio C

2016-01-01

Many postoperative complications have been reported after repair of classic bladder exstrophy. We present a case of medicinal leech therapy for glans penis congestion following exstrophy repair in an infant. A 2-week-old male with classic bladder exstrophy underwent complete primary repair. On postoperative day 1, he developed rapidly worsening glans penis venous congestion. Medicinal leech therapy was instituted with antibiotics and blood transfusions to maintain a hematocrit >30%. After 24 hours, venous congestion improved and therapy was discontinued. The patient's remaining hospital course was uncomplicated. Medicinal leeches are an effective therapy to relieve glans penis venous congestion. Copyright © 2015 Elsevier Inc. All rights reserved.

Phase diagram of congested traffic flow: An empirical study

PubMed

Lee; Lee; Kim

2000-10-01

We analyze traffic data from a highway section containing one effective on-ramp. Based on two criteria, local velocity variation patterns and expansion (or nonexpansion) of congested regions, three distinct congested traffic states are identified. These states appear at different levels of the upstream flux and the on-ramp flux, thereby generating a phase digram of the congested traffic flow. Observed traffic states are compared with recent theoretical analyses and both agreeing and disagreeing features are found.

Air traffic control : role of FAA's modernization program in reducing delays and congestion

DOT National Transportation Integrated Search

2001-05-10

The National Airspace System (NAS) is a complex collection of systems, procedures, facilities, aircraft, and people. Because these components are interconnected and interdependent, they must work together as one system to ensure safe operations. The ...

Supporting railroad roadway work communications with a wireless handheld computer. Volume 1 : usability for the roadway worker

DOT National Transportation Integrated Search

2004-10-01

Communications in current railroad operations rely heavily on voice communications. Radio congestion impairs roadway workers ability to communicate effectively with dispatchers at the Central Traffic Control Center and has adverse consequences for...

Supporting railroad roadway worker communications with a wireless handheld computer. Volume 1, Usability for the roadway worker.

DOT National Transportation Integrated Search

2004-10-31

Communications in current railroad operations rely heavily on voice communications. Radio congestion impairs roadway workers ability to communicate effectively with dispatchers at the Central Traffic Control Center and has adverse consequences for...

Evaluation of the public health impacts of traffic congestion: a health risk assessment.

PubMed

Levy, Jonathan I; Buonocore, Jonathan J; von Stackelberg, Katherine

2010-10-27

Traffic congestion is a significant issue in urban areas in the United States and around the world. Previous analyses have estimated the economic costs of congestion, related to fuel and time wasted, but few have quantified the public health impacts or determined how these impacts compare in magnitude to the economic costs. Moreover, the relative magnitudes of economic and public health impacts of congestion would be expected to vary significantly across urban areas, as a function of road infrastructure, population density, and atmospheric conditions influencing pollutant formation, but this variability has not been explored. In this study, we evaluate the public health impacts of ambient exposures to fine particulate matter (PM2.5) concentrations associated with a business-as-usual scenario of predicted traffic congestion. We evaluate 83 individual urban areas using traffic demand models to estimate the degree of congestion in each area from 2000 to 2030. We link traffic volume and speed data with the MOBILE6 model to characterize emissions of PM2.5 and particle precursors attributable to congestion, and we use a source-receptor matrix to evaluate the impact of these emissions on ambient PM2.5 concentrations. Marginal concentration changes are related to a concentration-response function for mortality, with a value of statistical life approach used to monetize the impacts. We estimate that the monetized value of PM2.5-related mortality attributable to congestion in these 83 cities in 2000 was approximately $31 billion (2007 dollars), as compared with a value of time and fuel wasted of $60 billion. In future years, the economic impacts grow (to over $100 billion in 2030) while the public health impacts decrease to $13 billion in 2020 before increasing to $17 billion in 2030, given increasing population and congestion but lower emissions per vehicle. Across cities and years, the public health impacts range from more than an order of magnitude less to in excess of the economic impacts. Our analyses indicate that the public health impacts of congestion may be significant enough in magnitude, at least in some urban areas, to be considered in future evaluations of the benefits of policies to mitigate congestion.

Development of congestion performance measures using ITS information.

DOT National Transportation Integrated Search

2003-01-01

The objectives of this study were to define a performance measure(s) that could be used to show congestion levels on critical corridors throughout Virginia and to develop a method to select and calculate performance measures to quantify congestion in...

Urban roadway congestion : annual report

DOT National Transportation Integrated Search

1998-01-01

The annual traffic congestion study is an effort to monitor roadway congestion in major urban areas in the United States. The comparisons to other areas and to previous experiences in each area are facilitated by a database that begins in 1982 and in...

A simulation-optimization-based decision support tool for mitigating traffic congestion.

DOT National Transportation Integrated Search

2009-12-01

"Traffic congestion has grown considerably in the United States over the past twenty years. In this paper, we develop : a robust decision support tool based on simulation optimization to evaluate and recommend congestion-mitigation : strategies to tr...

Power systems locational marginal pricing in deregulated markets

NASA Astrophysics Data System (ADS)

Wang, Hui-Fung Francis

Since the beginning of the 1990s, the electricity business is transforming from a vertical integrating business to a competitive market operations. The generation, transmission, distribution subsystem of an electricity utility are operated independently as Genco (generation subsystem), Transco (transmission subsystem), and Distco (distribution subsystem). This trend promotes more economical inter- and intra regional transactions to be made by the participating companies and the users of electricity to achieve the intended objectives of deregulation. There are various types of electricity markets that are implemented in the North America in the past few years. However, transmission congestion management becomes a key issue in the electricity market design as more bilateral transactions are traded across long distances competing for scarce transmission resources. It directly alters the traditional concept of energy pricing and impacts the bottom line, revenue and cost of electricity, of both suppliers and buyers. In this research, transmission congestion problem in a deregulated market environment is elucidated by implementing by the Locational Marginal Pricing (LMP) method. With a comprehensive understanding of the LMP method, new mathematical tools will aid electric utilities in exploring new business opportunities are developed and presented in this dissertation. The dissertation focuses on the development of concept of (LMP) forecasting and its implication to the market participants in deregulated market. Specifically, we explore methods of developing fast LMP calculation techniques that are differ from existing LMPs. We also explore and document the usefulness of the proposed LMP in determining electricity pricing of a large scale power system. The developed mathematical tools use of well-known optimization techniques such as linear programming that are support by several flow charts. The fast and practical security constrained unit commitment methods are the integral parts of the LMP algorithms. Different components of optimization techniques, unit commitment, power flow analysis, and matrix manipulations for large scale power systems are integrated and represented by several new flow charts. The LMP concept and processes, mathematical models, and their corresponding algorithms has been implemented to study a small six bus test power system/market and also the real size New York power system/market where the transmission congestion is high and electricity market is deregulated. The simulated results documented in the dissertation are satisfactory and produce very encouraging result when compared to the actual Located Based Marginal Price (LMP) results posted by the New York Independent System Operator (ISO). The further research opportunities inspired by this dissertation are also elaborated.

The diagnostic accuracy of physical examination compared to lung ultrasound for determining lung congestion in hemodialysis patients who have reached their dry weight

NASA Astrophysics Data System (ADS)

Rahardjo, K. D.; Dharmaeizar; Nainggolan, G.; Harimurti, K.

2017-08-01

Research has shown that hemodialysis patients with lung congestion have high morbidity and mortality. Patients were assumed to be free of lung congestion if they had reached their post-dialysis dry weight. Most often, to determine if the patient was free of lung congestion, physical examination was used. However, the accuracy of physical examination in detecting lung congestion has not been established. To compare the capabilities of physical examination and lung ultrasound in detection of lung congestion, cross-sectional data collection was conducted on hemodialysis patients. Analysis was done to obtain proportion, sensitivity, specificity, positive predictive value, negative predictive value, and positive likelihood ratio. Sixty patients participated in this study. The inter observer variation of 20 patients revealed a kappa value of 0.828. When all 60 patients were taken into account, we found that 36 patients (57.1%) had lung congestion. Mild lung congestion was found in 24 (38.1%), and 12 (19%) had a moderate degree of congestion. In the analysis comparing jugular venous pressure to lung ultrasound, we found that sensitivity was 0.47 (0.31-0.63), specificity was 0.73 (0.54-0.86), positive predictive value (PPV) was 0.51 (0.36-0.67), negative predictive value (NPV) was 0.70 (0.49-0.84), positive likelihood ratio (PLR) was 1.75 (0.88-3.47), and the negative likelihood ratio (NLR) was 0.72 (0.47-1.12). In terms of lung auscultation, we found that sensitivity was 0.56 (0.39-0.71), specificity was 0.54 (0.35-0.71), PPV was 0.61 (0.44-0.76), NPV was 0.48 (0.31-0.66), PLR was 1.21 (0.73-2.0), and NLR was 0.82 (0.49-1.38). The results of our study showed that jugular venous distention and lung auscultation examination are not reliable means of detecting lung congestion.

A New Procedure for Wrapped-Negative Pressure Wound Therapy for Congestion After Arterialized Venous Flap Surgery

PubMed Central

Niimi, Yosuke; Mori, Satoko; Takeuchi, Masaki

2017-01-01

Negative pressure wound therapy (NPWT) is a method for treating wound. However, there are no case reports using NPWT for treating congestion after arterialized venous flap. Therefore, this study reported favorable outcomes after using a single-use NPWT system for managing congestion. A 39-year-old man had his index finger caught by a press machine. The finger had a soft tissue defect at the ventral part. An arterialized venous flap taken from the right forearm was transplanted. Perfusion of the flap was favorable, but on postoperative day 5, congestion and the edema of the flap were found. Then, NPWT was initiated. The congestion and edema in the flap were improved without complications such as flap necrosis and wound infection. At 4 months postoperatively, the morphology of the finger was favorable. In this study, NPWT was speculated to force the deeper blood vessels within the flap to dilate with inducing drainage and the simultaneous reduction in excess blood flow to the cortical layer, resulting in the improvement of congestion. Negative pressure wound therapy was used for treating congestion after the transplantation of arterialized venous flap, and the wound was favorably managed. PMID:29270041

How Travel Demand Affects Detection of Non-Recurrent Traffic Congestion on Urban Road Networks

NASA Astrophysics Data System (ADS)

Anbaroglu, B.; Heydecker, B.; Cheng, T.

2016-06-01

Occurrence of non-recurrent traffic congestion hinders the economic activity of a city, as travellers could miss appointments or be late for work or important meetings. Similarly, for shippers, unexpected delays may disrupt just-in-time delivery and manufacturing processes, which could lose them payment. Consequently, research on non-recurrent congestion detection on urban road networks has recently gained attention. By analysing large amounts of traffic data collected on a daily basis, traffic operation centres can improve their methods to detect non-recurrent congestion rapidly and then revise their existing plans to mitigate its effects. Space-time clusters of high link journey time estimates correspond to non-recurrent congestion events. Existing research, however, has not considered the effect of travel demand on the effectiveness of non-recurrent congestion detection methods. Therefore, this paper investigates how travel demand affects detection of non-recurrent traffic congestion detection on urban road networks. Travel demand has been classified into three categories as low, normal and high. The experiments are carried out on London's urban road network, and the results demonstrate the necessity to adjust the relative importance of the component evaluation criteria depending on the travel demand level.

A Hardware-Supported Algorithm for Self-Managed and Choreographed Task Execution in Sensor Networks.

PubMed

Bordel, Borja; Miguel, Carlos; Alcarria, Ramón; Robles, Tomás

2018-03-07

Nowadays, sensor networks are composed of a great number of tiny resource-constraint nodes, whose management is increasingly more complex. In fact, although collaborative or choreographic task execution schemes are which fit in the most perfect way with the nature of sensor networks, they are rarely implemented because of the high resource consumption of these algorithms (especially if networks include many resource-constrained devices). On the contrary, hierarchical networks are usually designed, in whose cusp it is included a heavy orchestrator with a remarkable processing power, being able to implement any necessary management solution. However, although this orchestration approach solves most practical management problems of sensor networks, a great amount of the operation time is wasted while nodes request the orchestrator to address a conflict and they obtain the required instructions to operate. Therefore, in this paper it is proposed a new mechanism for self-managed and choreographed task execution in sensor networks. The proposed solution considers only a lightweight gateway instead of traditional heavy orchestrators and a hardware-supported algorithm, which consume a negligible amount of resources in sensor nodes. The gateway avoids the congestion of the entire sensor network and the hardware-supported algorithm enables a choreographed task execution scheme, so no particular node is overloaded. The performance of the proposed solution is evaluated through numerical and electronic ModelSim-based simulations.

A Two-Stage Algorithm for Origin-Destination Matrices Estimation Considering Dynamic Dispersion Parameter for Route Choice

PubMed Central

Wang, Yong; Ma, Xiaolei; Liu, Yong; Gong, Ke; Henricakson, Kristian C.; Xu, Maozeng; Wang, Yinhai

2016-01-01

This paper proposes a two-stage algorithm to simultaneously estimate origin-destination (OD) matrix, link choice proportion, and dispersion parameter using partial traffic counts in a congested network. A non-linear optimization model is developed which incorporates a dynamic dispersion parameter, followed by a two-stage algorithm in which Generalized Least Squares (GLS) estimation and a Stochastic User Equilibrium (SUE) assignment model are iteratively applied until the convergence is reached. To evaluate the performance of the algorithm, the proposed approach is implemented in a hypothetical network using input data with high error, and tested under a range of variation coefficients. The root mean squared error (RMSE) of the estimated OD demand and link flows are used to evaluate the model estimation results. The results indicate that the estimated dispersion parameter theta is insensitive to the choice of variation coefficients. The proposed approach is shown to outperform two established OD estimation methods and produce parameter estimates that are close to the ground truth. In addition, the proposed approach is applied to an empirical network in Seattle, WA to validate the robustness and practicality of this methodology. In summary, this study proposes and evaluates an innovative computational approach to accurately estimate OD matrices using link-level traffic flow data, and provides useful insight for optimal parameter selection in modeling travelers’ route choice behavior. PMID:26761209

A Hardware-Supported Algorithm for Self-Managed and Choreographed Task Execution in Sensor Networks

PubMed Central

2018-01-01

Nowadays, sensor networks are composed of a great number of tiny resource-constraint nodes, whose management is increasingly more complex. In fact, although collaborative or choreographic task execution schemes are which fit in the most perfect way with the nature of sensor networks, they are rarely implemented because of the high resource consumption of these algorithms (especially if networks include many resource-constrained devices). On the contrary, hierarchical networks are usually designed, in whose cusp it is included a heavy orchestrator with a remarkable processing power, being able to implement any necessary management solution. However, although this orchestration approach solves most practical management problems of sensor networks, a great amount of the operation time is wasted while nodes request the orchestrator to address a conflict and they obtain the required instructions to operate. Therefore, in this paper it is proposed a new mechanism for self-managed and choreographed task execution in sensor networks. The proposed solution considers only a lightweight gateway instead of traditional heavy orchestrators and a hardware-supported algorithm, which consume a negligible amount of resources in sensor nodes. The gateway avoids the congestion of the entire sensor network and the hardware-supported algorithm enables a choreographed task execution scheme, so no particular node is overloaded. The performance of the proposed solution is evaluated through numerical and electronic ModelSim-based simulations. PMID:29518986

An evaluation of congestion-reducing measures used in Virginia.

DOT National Transportation Integrated Search

1992-01-01

Congestion on our nation's highways, especially in urban areas, is a serious problem that is growing steadily worse. In Virginia, it is estimated that 28 percent of the daily vehicle miles of travel (VMT) occurring during peak hour traffic is congest...

Seasonal variation in traffic congestion : a study of three U.S. cities

DOT National Transportation Integrated Search

2008-08-01

Drivers may notice seasonal : changes in patterns of highway : congestion in many urban : areas of the country. These : patterns, however, can be very different for individual cities. : This report looks at congestion patterns over a 3-year period : ...

Projecting future landside congestion delays at the BWI Airport : final report.

DOT National Transportation Integrated Search

2003-10-01

This study examines the access to the BWI Airport in detail. Complex density functions are utilized to determine the : congestion curves faced by passengers arriving at the airport. It is found that all lots have congestion during peak : periods and ...

Long Island Transportation Plan to Manage Congestion: Framework for Developing and Evaluating Improvement Strategies

DOT National Transportation Integrated Search

2002-04-20

The Long Island Transportation Plan to Manage Congestion (LITP 2000) will establish an integrated, multi-modal transportation program of cost-effective strategies to manage congestion and improve the movement of people and goods in Nassau and Suffolk...

Effects of a System Thinking-Based Simulation Program for Congestive Heart Failure.

PubMed

Kim, Hyeon-Young; Yun, Eun Kyoung

2018-03-01

This study evaluated a system thinking-based simulation program for the care of patients with congestive heart failure. Participants were 67 undergraduate nursing students from a nursing college in Seoul, South Korea. The experimental group was given a 4-hour system-thinking program and a 2-hour simulation program, whereas the control group had a 4-hour case study and a 2-hour simulation program. There were significant improvements in critical thinking in both groups, but no significant group differences between educational methods (F = 3.26, P = .076). Problem-solving ability in the experimental group was significantly higher than in the control group (F = 5.04, P = .028). Clinical competency skills in the experimental group were higher than in the control group (t = 2.12, P = .038). A system thinking-based simulation program is a more effective learning method in terms of problem-solving ability and clinical competency skills compared to the existing simulation program. Further research using a longitudinal study is needed to test the long-term effect of the intervention and apply it to the nursing curriculum.

Traffic jams induced by fluctuation of a leading car.

PubMed

Nagatani, T

2000-04-01

We present a phase diagram of the different kinds of congested traffic triggered by fluctuation of a leading car in an open system without sources and sinks. Traffic states and density waves are investigated numerically by varying the amplitude of fluctuation using a car following model. The phase transitions among the free traffic, oscillatory congested traffic, and homogeneous congested traffic occur by fluctuation of a leading car. With increasing the amplitude of fluctuation, the transition between the free traffic and oscillatory traffic occurs at lower density and the transition between the homogeneous congested traffic and the oscillatory traffic occurs at higher density. The oscillatory congested traffic corresponds to the coexisting phase. Also, the moving localized clusters appear just above the transition lines.

The role of pseudoephedrine on daytime somnolence in patients suffering from perennial allergic rhinitis (PAR).

PubMed

Sherkat, Amir A; Sardana, Niti; Safaee, Sahar; Lehman, Erik B; Craig, Timothy J

2011-02-01

Allergic rhinitis is one of several inflammatory diseases affecting the nasal mucosa. Cellular inflammation of nasal mucosa is a hallmark of this disease and is characterized by the accumulation of eosinophils and the release of various chemical messengers such as chemokines, cytokines, and histamine. This inflammation of the nose leads to nasal congestion and a reduction in sleep quality, resulting in daytime somnolence. Drugs that significantly reduce the symptoms of nasal congestion also may help in alleviating sleep-related symptoms of allergic rhinitis. Pseudoephedrine is a sympathomimetic amine that is indicated for treatment of nasal congestion associated with allergic rhinitis. Despite relieving nasal congestion, we speculated that, because of pseudoephedrine's well-known stimulant profile, sleep would not be improved. Fourteen subjects who met the inclusion criteria were enrolled into a double-blind, placebo-controlled, randomized study to either pseudoephedrine or placebo once per day in the morning, using the traditional crossover design. Skin testing test was performed to ensure a positive response to a relevant perennial allergen and a negative response to a seasonal allergen. Several questionnaires were used to evaluate the patients' sleep-related symptoms, allergic rhinitis symptoms, and quality of life. Our results showed that pseudoephedrine did not have a positive or negative effect on quality of sleep, daytime sleepiness, or daytime fatigue as compared with placebo. Pseudoephedrine did show a statistical significance in improving stuffy nose (P = .0172). With respect to quality of life, pseudoephedrine led to a statistically significant decrease in intimate relationships and sexual activity as compared with the placebo group (P = .0310). Our research suggests that sleep quality is not significantly affected by pseudoephedrine. As expected, congestion is reduced, but side effects such as a decline of intimate relationships and sexual activity may interfere with quality of life. Copyright © 2011 American College of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.

Enhancing CORSIM for simulating high occupancy/toll lane operations.

DOT National Transportation Integrated Search

2012-03-15

Congestion pricing has been advocated as an efficient way to mitigate traffic congestion : since 1920s. A prevalent form of congestion pricing in the U.S. is high occupancy/toll (HOT) : lanes. The operating objective of HOT lanes is to improve the th...

23 CFR 500.109 - CMS.

Code of Federal Regulations, 2011 CFR

2011-04-01

.... Congestion management means the application of strategies to improve system performance and reliability by... SYSTEMS Management Systems § 500.109 CMS. (a) For purposes of this part, congestion means the level at... management system or process is a systematic and regionally accepted approach for managing congestion that...

23 CFR 500.109 - CMS.

Code of Federal Regulations, 2010 CFR

2010-04-01

.... Congestion management means the application of strategies to improve system performance and reliability by... SYSTEMS Management Systems § 500.109 CMS. (a) For purposes of this part, congestion means the level at... management system or process is a systematic and regionally accepted approach for managing congestion that...

23 CFR 500.109 - CMS.

Code of Federal Regulations, 2013 CFR

2013-04-01

... SYSTEMS Management Systems § 500.109 CMS. (a) For purposes of this part, congestion means the level at.... Congestion management means the application of strategies to improve system performance and reliability by... management system or process is a systematic and regionally accepted approach for managing congestion that...

23 CFR 500.109 - CMS.

Code of Federal Regulations, 2014 CFR

2014-04-01

... SYSTEMS Management Systems § 500.109 CMS. (a) For purposes of this part, congestion means the level at.... Congestion management means the application of strategies to improve system performance and reliability by... management system or process is a systematic and regionally accepted approach for managing congestion that...

23 CFR 500.109 - CMS.

Code of Federal Regulations, 2012 CFR

2012-04-01

... SYSTEMS Management Systems § 500.109 CMS. (a) For purposes of this part, congestion means the level at.... Congestion management means the application of strategies to improve system performance and reliability by... management system or process is a systematic and regionally accepted approach for managing congestion that...

Value of travel-time reliability, part II : a study of tradeoffs between travel reliability, congestion-mitigation strategies and emissions.

DOT National Transportation Integrated Search

2012-09-01

Capacity, demand, and vehicle based emissions reduction strategies are compared for several pollutants employing aggregate US : congestion and vehicle fleet condition data. We find that congestion mitigation does not inevitably lead to reduced emissi...

Statewide planning scenario synthesis : transportation congestion measurement and management.

DOT National Transportation Integrated Search

2005-09-01

This study is a review of current practices in 13 states to: (1) measure traffic congestion and its costs; and (2) manage congestion with programs and techniques that do not involve the building of new highway capacity. In regard to the measures of c...

Substance P contributes to rapidly adapting receptor responses to pulmonary venous congestion in rabbits.

PubMed

Bonham, A C; Kott, K S; Ravi, K; Kappagoda, C T; Joad, J P

1996-05-15

1. This study tested the hypothesis that substance P stimulates rapidly adapting receptors (RARs), contributes to the increase in RAR activity produced by mild pulmonary congestion, and evokes an augmented response from RARs when combined with near-threshold levels of pulmonary congestion. 2. RAR activity, peak tracheal pressure, arterial blood pressure and left atrial pressure were measured in paralysed, anaesthetized and ventilated rabbits. Substance P was given i.v. in one-half log incremental doses to a maximum of 3 micrograms kg-1. Mild pulmonary congestion was produced by inflating a balloon in the left atrium to increase left atrial pressure by 5 mmHg. Near-threshold levels of pulmonary congestion were produced by increasing left atrial pressure by 2 mmHg. 3. Substance P produced dose-dependent increases in RAR activity. The highest dose given increased the activity from 1.3 +/- 0.5 to 11.0 +/- 3.1 impulses bin-1. Increases in left atrial pressure of 5 mmHg increased RAR activity from 3.8 +/- 1.4 to 14.7 +/- 3.9 impulses bin-1. Blockade of NK1 receptors with CP 96345 significantly attenuated RAR responses to substance P and to mild pulmonary congestion. 4. Doses of substance P, which alone had no effect, stimulated the RARs when delivered during near-threshold levels of pulmonary congestion. 5. The findings suggest that substance P augments the stimulatory effect of mild pulmonary congestion on RAR activity, most probably by enhancing hydraulically induced microvascular leak.

Disease management 360 degrees: a scorecard approach to evaluating TRICARE's programs for asthma, congestive heart failure, and diabetes.

PubMed

Yang, Wenya; Dall, Timothy M; Zhang, Yiduo; Hogan, Paul F; Arday, David R; Gantt, Cynthia J

2010-08-01

To assess the effect of TRICARE's asthma, congestive heart failure, and diabetes disease management programs using a scorecard approach. EVALUATION MEASURES: Patient healthcare utilization, financial, clinical, and humanistic outcomes. Absolute measures were translated into effect size and incorporated into a scorecard. Actual outcomes for program participants were compared with outcomes predicted in the absence of disease management. The predictive equations were established from regression models based on historical control groups (n = 39,217). Z scores were calculated for the humanistic measures obtained through a mailed survey. Administrative records containing medical claims, patient demographics and characteristics, and program participation status were linked using an encrypted patient identifier (n = 57,489). The study time frame is 1 year prior to program inception through 2 years afterward (October 2005-September 2008). A historical control group was identified with the baseline year starting October 2003 and a 1-year follow-up period starting October 2004. A survey was administered to a subset of participants 6 months after baseline assessment (39% response rate). Within the observation window--24 months for asthma and congestive heart failure, and 15 months for the diabetes program--we observed modest reductions in hospital days and healthcare cost for all 3 programs and reductions in emergency visits for 2 programs. Most clinical outcomes moved in the direction anticipated. The scorecard provided a useful tool to track performance of 3 regional contractors for each of 3 diseases and over time.

76 FR 34848 - Drawbridge Operation Regulation; Atlantic Intracoastal Waterway (AIWW), Elizabeth River, Southern...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-06-15

... until December 20, 2013, relieving vehicular traffic congestion during the weekday and weekend daytime... final temporary could result in additional vehicular traffic congestion without providing any additional... anticipates continued vehicular traffic congestion over the Gilmerton Highway Bridge due to the reduction of...

Alternative Fuels Data Center: Deploying Alternative Fuel Vehicles and

Science.gov Websites

Infrastructure in Chicago, Illinois, Through the Congestion Mitigation and Air Quality Improvement Program and Infrastructure in Chicago, Illinois, Through the Congestion Mitigation and Air Quality Vehicles and Infrastructure in Chicago, Illinois, Through the Congestion Mitigation and Air Quality

Urban partnership agreement and congestion reduction demonstration programs : lessons learned on congestion pricing from the Seattle and Atlanta household travel behavior surveys.

DOT National Transportation Integrated Search

2014-04-01

This paper presents lessons learned from household traveler surveys administered in Seattle and Atlanta as part of the evaluation of the Urban Partnership Agreement and Congestion Reduction Demonstration Programs. The surveys use a two-stage panel su...

23 CFR 970.214 - Federal lands congestion management system (CMS).

Code of Federal Regulations, 2011 CFR

2011-04-01

... experiencing congestion, the NPS shall develop a separate CMS to cover those facilities. Approaches may include... congestion management strategies; (v) Determine methods to monitor and evaluate the performance of the multi... means the level at which transportation system performance is no longer acceptable due to traffic...

23 CFR 970.214 - Federal lands congestion management system (CMS).

Code of Federal Regulations, 2010 CFR

2010-04-01

... experiencing congestion, the NPS shall develop a separate CMS to cover those facilities. Approaches may include... congestion management strategies; (v) Determine methods to monitor and evaluate the performance of the multi... means the level at which transportation system performance is no longer acceptable due to traffic...

23 CFR 973.214 - Indian lands congestion management system (CMS).

Code of Federal Regulations, 2014 CFR

2014-04-01

... 23 Highways 1 2014-04-01 2014-04-01 false Indian lands congestion management system (CMS). 973.214... HIGHWAYS MANAGEMENT SYSTEMS PERTAINING TO THE BUREAU OF INDIAN AFFAIRS AND THE INDIAN RESERVATION ROADS PROGRAM Bureau of Indian Affairs Management Systems § 973.214 Indian lands congestion management system...

Feasibility of incorporating crash risk in developing congestion mitigation measures for interstate highways : a case study of the Hampton Roads area.

DOT National Transportation Integrated Search

2002-01-01

A relationship between traffic flow variables and crash characteristics can greatly help the traffic engineer in the field to arrive at appropriate congestion mitigation measures that not only alleviate congestion and save time but also reduce the pr...

14 CFR 137.49 - Operations over other than congested areas.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Operations over other than congested areas. 137.49 Section 137.49 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... congested areas below 500 feet above the surface and closer than 500 feet to persons, vessels, vehicles, and...

76 FR 70122 - Plan for Conduct of 2012 Electric Transmission Congestion Study

Federal Register 2010, 2011, 2012, 2013, 2014

2011-11-10

... preparations for the 2012 Congestion Study, and seeks comments on what publicly-available data and information...), and Microsoft PowerPoint (.ppt). The Department intends to use only data that is publicly available... Study, the Department gathered historical congestion data obtained from existing studies prepared by...

Quantum random walks on congested lattices and the effect of dephasing.

PubMed

Motes, Keith R; Gilchrist, Alexei; Rohde, Peter P

2016-01-27

We consider quantum random walks on congested lattices and contrast them to classical random walks. Congestion is modelled on lattices that contain static defects which reverse the walker's direction. We implement a dephasing process after each step which allows us to smoothly interpolate between classical and quantum random walks as well as study the effect of dephasing on the quantum walk. Our key results show that a quantum walker escapes a finite boundary dramatically faster than a classical walker and that this advantage remains in the presence of heavily congested lattices.

Integrative Assessment of Congestion in Heart Failure Throughout the Patient Journey.

PubMed

Girerd, Nicolas; Seronde, Marie-France; Coiro, Stefano; Chouihed, Tahar; Bilbault, Pascal; Braun, François; Kenizou, David; Maillier, Bruno; Nazeyrollas, Pierre; Roul, Gérard; Fillieux, Ludivine; Abraham, William T; Januzzi, James; Sebbag, Laurent; Zannad, Faiez; Mebazaa, Alexandre; Rossignol, Patrick

2018-04-01

Congestion is one of the main predictors of poor patient outcome in patients with heart failure. However, congestion is difficult to assess, especially when symptoms are mild. Although numerous clinical scores, imaging tools, and biological tests are available to assist physicians in ascertaining and quantifying congestion, not all are appropriate for use in all stages of patient management. In recent years, multidisciplinary management in the community has become increasingly important to prevent heart failure hospitalizations. Electronic alert systems and communication platforms are emerging that could be used to facilitate patient home monitoring that identifies congestion from heart failure decompensation at an earlier stage. This paper describes the role of congestion detection methods at key stages of patient care: pre-admission, admission to the emergency department, in-hospital management, and lastly, discharge and continued monitoring in the community. The multidisciplinary working group, which consisted of cardiologists, emergency physicians, and a nephrologist with both clinical and research backgrounds, reviewed the current literature regarding the various scores, tools, and tests to detect and quantify congestion. This paper describes the role of each tool at key stages of patient care and discusses the advantages of telemedicine as a means of providing true integrated patient care. Copyright © 2018. Published by Elsevier Inc.

Does rush hour see a rush of emotions? Driver mood in conditions likely to exhibit congestion

PubMed Central

Morris, Eric A; Hirsch, Jana A.

2016-01-01

Polls show that a large portion of the public considers traffic congestion to be a problem and believes a number of policy interventions would ameliorate it. However, most of the public rejects new taxes and fees to fund these improvements. This may be because of a disconnect between the public's stated antipathy towards congestion and the recalled emotional costs congestion imposes. To explore this, we use a large and representative sample drawn from the American Time Use Survey to examine how drivers experience four emotions (happiness, sadness, stress, and fatigue), plus a constructed composite mood variable, when they travel in peak periods, in large cities, in city centers, and in combinations of these. We also explore the interactions between these indicators and trip duration. We find evidence that drivers in the largest cities at the very peak of rush hour (5:00pm-6:00pm) are in a less positive mood, presumably because of congestion. However, this effect, though significant, is small, and we find no significant results using broader definitions of the peak period. In all, our findings suggest that congestion's impact on drivers as a group is quite limited. This may help explain why the public's attitude toward painful financial trade-offs to address congestion is lukewarm. PMID:27231669

Evaluation of the public health impacts of traffic congestion: a health risk assessment

PubMed Central

2010-01-01

Background Traffic congestion is a significant issue in urban areas in the United States and around the world. Previous analyses have estimated the economic costs of congestion, related to fuel and time wasted, but few have quantified the public health impacts or determined how these impacts compare in magnitude to the economic costs. Moreover, the relative magnitudes of economic and public health impacts of congestion would be expected to vary significantly across urban areas, as a function of road infrastructure, population density, and atmospheric conditions influencing pollutant formation, but this variability has not been explored. Methods In this study, we evaluate the public health impacts of ambient exposures to fine particulate matter (PM2.5) concentrations associated with a business-as-usual scenario of predicted traffic congestion. We evaluate 83 individual urban areas using traffic demand models to estimate the degree of congestion in each area from 2000 to 2030. We link traffic volume and speed data with the MOBILE6 model to characterize emissions of PM2.5 and particle precursors attributable to congestion, and we use a source-receptor matrix to evaluate the impact of these emissions on ambient PM2.5 concentrations. Marginal concentration changes are related to a concentration-response function for mortality, with a value of statistical life approach used to monetize the impacts. Results We estimate that the monetized value of PM2.5-related mortality attributable to congestion in these 83 cities in 2000 was approximately $31 billion (2007 dollars), as compared with a value of time and fuel wasted of $60 billion. In future years, the economic impacts grow (to over $100 billion in 2030) while the public health impacts decrease to $13 billion in 2020 before increasing to $17 billion in 2030, given increasing population and congestion but lower emissions per vehicle. Across cities and years, the public health impacts range from more than an order of magnitude less to in excess of the economic impacts. Conclusions Our analyses indicate that the public health impacts of congestion may be significant enough in magnitude, at least in some urban areas, to be considered in future evaluations of the benefits of policies to mitigate congestion. PMID:20979626

Active Traffic Management: Comprehension, Legibility, Distance, and Motorist Behavior In Response to Selected Variable Speed Limit and Lane Control Signing

DOT National Transportation Integrated Search

2016-06-01

Active traffic management (ATM) incorporates a collection of strategies allowing the dynamic management of recurrent and nonrecurrent congestion based on prevailing traffic conditions. These strategies help to increase peak capacity, smooth traffic f...

21 CFR 870.5225 - External counter-pulsating device.

Code of Federal Regulations, 2014 CFR

2014-04-01

..., prescription device used to assist the heart by applying positive or negative pressure to one or more of the body's limbs in synchrony with the heart cycle. (b) Classification. (1) Class II (special controls... angina pectoris; acute myocardial infarction; cardiogenic shock; congestive heart failure; postoperative...

A kinematic wave model in Lagrangian coordinates incorporating capacity drop: Application to homogeneous road stretches and discontinuities

NASA Astrophysics Data System (ADS)

Yuan, Kai; Knoop, Victor L.; Hoogendoorn, Serge P.

2017-01-01

On freeways, congestion always leads to capacity drop. This means the queue discharge rate is lower than the pre-queue capacity. Our recent research findings indicate that the queue discharge rate increases with the speed in congestion, that is the capacity drop is strongly correlated with the congestion state. Incorporating this varying capacity drop into a kinematic wave model is essential for assessing consequences of control strategies. However, to the best of authors' knowledge, no such a model exists. This paper fills the research gap by presenting a Lagrangian kinematic wave model. "Lagrangian" denotes that the new model is solved in Lagrangian coordinates. The new model can give capacity drops accompanying both of stop-and-go waves (on homogeneous freeway section) and standing queues (at nodes) in a network. The new model can be applied in a network operation. In this Lagrangian kinematic wave model, the queue discharge rate (or the capacity drop) is a function of vehicular speed in traffic jams. Four case studies on links as well as at lane-drop and on-ramp nodes show that the Lagrangian kinematic wave model can give capacity drops well, consistent with empirical observations.

Plasma lipophilic antioxidants and malondialdehyde in congestive heart failure patients: relationship to disease severity.

PubMed

Polidori, Maria Cristina; Savino, Ketty; Alunni, Gianfranco; Freddio, Michela; Senin, Umberto; Sies, Helmut; Stahl, Wilhelm; Mecocci, Patrizia

2002-01-15

Plasma levels of malondialdehyde (MDA), vitamin A, and of antioxidant micronutrients including vitamin E, lutein, zeaxanthin, beta-cryptoxanthin, lycopene, and alpha- and beta-carotene were measured in 30 patients with class II and III congestive heart failure (CHF) according to the New York Heart Association (NYHA) classification and in 55 controls. Ejection fraction was evaluated by echocardiography in all patients as a measure of the emptying capacity of the heart. Plasma levels of all measured compounds were significantly lower and MDA significantly higher in patients compared to controls (p <.001). Class II NYHA patients showed significantly lower MDA levels and significantly higher levels of vitamin A, vitamin E, lutein, and lycopene than class III patients. Ejection fraction was inversely correlated with MDA levels and directly correlated with vitamin A, vitamin E, lutein, and lycopene levels in patients. The present study supports the concept that an increased consumption of vitamin-rich fruits and vegetables might help in achieving cardiovascular health.

QTCM Software Documentation. Volume 1. Programmers’s Manual

DTIC Science & Technology

1990-11-01

technologies are implemented. Since the PSNs are comprised of private companies, the OMNCS has little direct control over how they operate and the... control equipment at each node to prevent any congestion at the switches. Therefore, all call blocking is modeled to occur at the trunks rather than at the...main program is linked with separately compiled subroutines that can be grouped intoI seven distinct functional areas as follows: Control code File

Simulating and evaluating an adaptive and integrated traffic lights control system for smart city application

NASA Astrophysics Data System (ADS)

Djuana, E.; Rahardjo, K.; Gozali, F.; Tan, S.; Rambung, R.; Adrian, D.

2018-01-01

A city could be categorized as a smart city when the information technology has been developed to the point that the administration could sense, understand, and control every resource to serve its people and sustain the development of the city. One of the smart city aspects is transportation and traffic management. This paper presents a research project to design an adaptive traffic lights control system as a part of the smart system for optimizing road utilization and reducing congestion. Research problems presented include: (1) Congestion in one direction toward an intersection due to dynamic traffic condition from time to time during the day, while the timing cycles in traffic lights system are mostly static; (2) No timing synchronization among traffic lights in adjacent intersections that is causing unsteady flows; (3) Difficulties in traffic condition monitoring on the intersection and the lack of facility for remotely controlling traffic lights. In this research, a simulator has been built to model the adaptivity and integration among different traffic lights controllers in adjacent intersections, and a case study consisting of three sets of intersections along Jalan K. H. Hasyim Ashari has been simulated. It can be concluded that timing slots synchronization among traffic lights is crucial for maintaining a steady traffic flow.

Prevalence and Clinical Correlates of Sarcopenia, Identified According to the EWGSOP Definition and Diagnostic Algorithm, in Hospitalized Older People: The GLISTEN Study.

PubMed

Bianchi, Lara; Abete, Pasquale; Bellelli, Giuseppe; Bo, Mario; Cherubini, Antonio; Corica, Francesco; Di Bari, Mauro; Maggio, Marcello; Manca, Giovanna Maria; Rizzo, Maria Rosaria; Rossi, Andrea P; Landi, Francesco; Volpato, Stefano

2017-10-12

Prevalence of sarcopenia is substantial in most geriatrics settings, but estimates vary greatly across studies because of difference in population characteristics, diagnostic criteria, and methods used to assess muscle mass, muscle strength, and physical performance. We investigated the feasibility of the European Working Group on Sarcopenia in Older People (EWGSOP) algorithm assessment in hospitalized older adults and analyzed prevalence and clinical correlates of sarcopenia. Cross-sectional analysis of 655 participants enrolled in a multicenter observational study of older adults admitted to 12 acute hospital wards in Italy. Sarcopenia was assessed as low skeletal mass index (kg/m2) plus either low handgrip strength or low walking speed (EWGSOP criteria). Skeletal muscle mass was estimated using bioimpedance analysis. Of the 655 patients (age 81.0 ± 6.8 years; women 51.9%) enrolled in the study, 275 (40.2%) were not able to perform the 4-m walking test because of medical problems. The overall prevalence of sarcopenia on hospital admission was 34.7% (95% confidence interval 28-37) and it steeply increased with aging (p < .001). In multivariable analysis, patients with sarcopenia on hospital admission were older and were more likely to be male and to have congestive heart failure, cerebrovascular disease, and severe basic activities of daily living disability. The prevalence of sarcopenia was inversely correlated with body mass index. Based on EWGSOP criteria, prevalence of sarcopenia is extremely high among older adults on admission to acute hospital wards. Older age, male gender, congestive heart failure, cerebrovascular disease, severe activities of daily living disability, and body mass index were the clinical variables significantly associated with the presence of sarcopenia. © The Author 2017. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Networking—a statistical physics perspective

NASA Astrophysics Data System (ADS)

Yeung, Chi Ho; Saad, David

2013-03-01

Networking encompasses a variety of tasks related to the communication of information on networks; it has a substantial economic and societal impact on a broad range of areas including transportation systems, wired and wireless communications and a range of Internet applications. As transportation and communication networks become increasingly more complex, the ever increasing demand for congestion control, higher traffic capacity, quality of service, robustness and reduced energy consumption requires new tools and methods to meet these conflicting requirements. The new methodology should serve for gaining better understanding of the properties of networking systems at the macroscopic level, as well as for the development of new principled optimization and management algorithms at the microscopic level. Methods of statistical physics seem best placed to provide new approaches as they have been developed specifically to deal with nonlinear large-scale systems. This review aims at presenting an overview of tools and methods that have been developed within the statistical physics community and that can be readily applied to address the emerging problems in networking. These include diffusion processes, methods from disordered systems and polymer physics, probabilistic inference, which have direct relevance to network routing, file and frequency distribution, the exploration of network structures and vulnerability, and various other practical networking applications.

Substance P contributes to rapidly adapting receptor responses to pulmonary venous congestion in rabbits.

PubMed Central

Bonham, A C; Kott, K S; Ravi, K; Kappagoda, C T; Joad, J P

1996-01-01

1. This study tested the hypothesis that substance P stimulates rapidly adapting receptors (RARs), contributes to the increase in RAR activity produced by mild pulmonary congestion, and evokes an augmented response from RARs when combined with near-threshold levels of pulmonary congestion. 2. RAR activity, peak tracheal pressure, arterial blood pressure and left atrial pressure were measured in paralysed, anaesthetized and ventilated rabbits. Substance P was given i.v. in one-half log incremental doses to a maximum of 3 micrograms kg-1. Mild pulmonary congestion was produced by inflating a balloon in the left atrium to increase left atrial pressure by 5 mmHg. Near-threshold levels of pulmonary congestion were produced by increasing left atrial pressure by 2 mmHg. 3. Substance P produced dose-dependent increases in RAR activity. The highest dose given increased the activity from 1.3 +/- 0.5 to 11.0 +/- 3.1 impulses bin-1. Increases in left atrial pressure of 5 mmHg increased RAR activity from 3.8 +/- 1.4 to 14.7 +/- 3.9 impulses bin-1. Blockade of NK1 receptors with CP 96345 significantly attenuated RAR responses to substance P and to mild pulmonary congestion. 4. Doses of substance P, which alone had no effect, stimulated the RARs when delivered during near-threshold levels of pulmonary congestion. 5. The findings suggest that substance P augments the stimulatory effect of mild pulmonary congestion on RAR activity, most probably by enhancing hydraulically induced microvascular leak. Images Figure 6 PMID:8735708

Stability of power systems coupled with market dynamics

NASA Astrophysics Data System (ADS)

Meng, Jianping

This Ph.D. thesis presented here spans two relatively independent topics. The first part, Chapter 2 is self-contained, and is dedicated to studies of new algorithms for power system state estimation. The second part, encompassing the remaining chapters, is dedicated to stability analysis of power system coupled with market dynamics. The first part of this thesis presents improved Newton's methods employing efficient vectorized calculations of higher order derivatives in power system state estimation problems. The improved algorithms are proposed based on an exact Newton's method using the second order terms. By efficiently computing an exact gain matrix, combined with a special optimal multiplier method, the new algorithms show more reliable convergence compared with the existing methods of normal equations, orthogonal decomposition, and Hachtel's sparse tableau. Our methods are able to handle ill-conditioned problems, yet show minimal penalty in computational cost for well-conditioned cases. These claims are illustrated through the standard IEEE 118 and 300 bus test examples. The second part of the thesis focuses on stability analysis of market/power systems. The work presented is motivated by an emerging problem. As the frequency of market based dispatch updates increases, there will inevitably be interaction between the dynamics of markets determining the generator dispatch commands, and the physical response of generators and network interconnections, necessitating the development of stability analysis for such coupled systems. We begin with numeric tests using different market models, with detailed machine/exciter/turbine/governor dynamics, in the New England 39 bus test system. A progression of modeling refinements are introduced, including such non-ideal effects as time delays. Electricity market parameter identification algorithms are also studied based on real time data from the PJM electricity market. Finally our power market model is augmented by optimal power flow constraints, allowing study of the so-called congestion problem. These studies show that understanding of potential modes of instability in such coupled systems is of crucial importance both in designing suitable rules for power markets, and in designing physical generator controls that are complementary to market-based dispatch.

75 FR 69906 - Drawbridge Operation Regulation; Atlantic Intracoastal Waterway (AIWW), Elizabeth River, Southern...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-16

... opening periods for the bridge during the day, relieving vehicular traffic congestion during the weekday... the rush hour periods and on the weekends, we anticipate a decrease in vehicular traffic congestion... vehicular traffic congestion over the Gilmerton Highway Bridge due to the reduction of highway lanes and...

Financial and technical feasibility of dynamic congestion pricing as a revenue generation source in Indiana : exploiting the availability of real-time information and dynamic pricing technologies.

DOT National Transportation Integrated Search

2011-10-19

"Highway stakeholders continue to support research studies that address critical issues of the current era, including congestion mitigation and revenue generation. A mechanism that addresses both concerns is congestion pricing which establishes a dir...

Effect of chronic mitral valve damage on activity of pulmonary rapidly adapting receptors in the rabbit

PubMed Central

Gunawardena, S; Bravo, E; Kappagoda, C T

1998-01-01

The effects of acute pulmonary venous congestion on the activity of rapidly adapting receptors (RARs) were determined in intact (control and sham-operated) rabbits and in rabbits 6 and 12 weeks after surgical destruction of the mitral valve.Destruction of the mitral valve increased the mean left atrial pressure (LAP) by approximately 2·6 and 3·8 mmHg, 6 and 12 weeks after surgery, respectively. These changes were accompanied by significant increases in left ventricular weight. The effect of acute increments in LAP on RAR activity was examined against this background of chronic pulmonary venous congestion.In intact control and sham-operated animals RAR activity increased from 48·8 ± 0·9 to 83·5 ± 3·6 and 121·1 ± 4·7 action potentials min−1 when the LAP was raised by 5 and 10 mmHg, respectively, above control values. Six weeks after surgery only 40 % of RARs were activated in this way.In animals maintained for 12 weeks after surgery, RAR activity at LAPs of 6·6 ± 1·2 (control), 11·6 ± 1·2 and 16·6 ± 1·2 (mmHg) were 35·5 ± 2·3, 33·8 ± 14·4 and 34·0 ± 3·4 action potentials min−1, respectively. These changes were statistically not significant.Slowly adapting receptors (SARs) in the lung showed a small but statistically significant increase in activity when the left atrial pressure was acutely elevated in both intact and mitral valve damaged animals.It is concluded that chronic pulmonary venous congestion resulting from destruction of the mitral valve attenuates the ability of RARs to respond to acute moderate elevations of LAP. PMID:9679165

Understanding congested travel in urban areas

PubMed Central

Çolak, Serdar; Lima, Antonio; González, Marta C.

2016-01-01

Rapid urbanization and increasing demand for transportation burdens urban road infrastructures. The interplay of number of vehicles and available road capacity on their routes determines the level of congestion. Although approaches to modify demand and capacity exist, the possible limits of congestion alleviation by only modifying route choices have not been systematically studied. Here we couple the road networks of five diverse cities with the travel demand profiles in the morning peak hour obtained from billions of mobile phone traces to comprehensively analyse urban traffic. We present that a dimensionless ratio of the road supply to the travel demand explains the percentage of time lost in congestion. Finally, we examine congestion relief under a centralized routing scheme with varying levels of awareness of social good and quantify the benefits to show that moderate levels are enough to achieve significant collective travel time savings. PMID:26978719

Understanding congested travel in urban areas

NASA Astrophysics Data System (ADS)

Çolak, Serdar; Lima, Antonio; González, Marta C.

2016-03-01

Rapid urbanization and increasing demand for transportation burdens urban road infrastructures. The interplay of number of vehicles and available road capacity on their routes determines the level of congestion. Although approaches to modify demand and capacity exist, the possible limits of congestion alleviation by only modifying route choices have not been systematically studied. Here we couple the road networks of five diverse cities with the travel demand profiles in the morning peak hour obtained from billions of mobile phone traces to comprehensively analyse urban traffic. We present that a dimensionless ratio of the road supply to the travel demand explains the percentage of time lost in congestion. Finally, we examine congestion relief under a centralized routing scheme with varying levels of awareness of social good and quantify the benefits to show that moderate levels are enough to achieve significant collective travel time savings.

Integrated arterial and freeway operation control strategies for IVHS advanced traffic management systems : research report

DOT National Transportation Integrated Search

1998-09-01

The main focus of this study is congestion, primarily that occurring on freeway corridors in metropolitan areas. Lack of coordination in the operation of various components of the system is often a major source of inefficiency, : resulting in greater...

Application of the stochastic optimization method in optimizing traffic signal control settings.

DOT National Transportation Integrated Search

2008-01-01

Traffic congestion has greatly affected not only the nation's economy and environment but also every citizen's quality of life. A recent study shows that every American traveler spent an extra 38 hours and 26 gallons of fuel per year due to traffic c...

A Sharp methodology for VLSI layout

NASA Astrophysics Data System (ADS)

Bapat, Shekhar

1993-01-01

The layout problem for VLSI circuits is recognized as a very difficult problem and has been traditionally decomposed into the several seemingly independent sub-problems of placement, global routing, and detailed routing. Although this structure achieves a reduction in programming complexity, it is also typically accompanied by a reduction in solution quality. Most current placement research recognizes that the separation is artificial, and that the placement and routing problems should be solved ideally in tandem. We propose a new interconnection model, Sharp and an associated partitioning algorithm. The Sharp interconnection model uses a partitioning shape that roughly resembles the musical sharp 'number sign' and makes extensive use of pre-computed rectilinear Steiner trees. The model is designed to generate strategic routing information along with the partitioning results. Additionally, the Sharp model also generates estimates of the routing congestion. We also propose the Sharp layout heuristic that solves the layout problem in its entirety. The Sharp layout heuristic makes extensive use of the Sharp partitioning model. The use of precomputed Steiner tree forms enables the method to model accurately net characteristics. For example, the Steiner tree forms can model both the length of the net and more importantly its route. In fact, the tree forms are also appropriate for modeling the timing delays of nets. The Sharp heuristic works to minimize both the total layout area by minimizing total net length (thus reducing the total wiring area), and the congestion imbalances in the various channels (thus reducing the unused or wasted channel area). Our heuristic uses circuit element movements amongst the different partitioning blocks and selection of alternate minimal Steiner tree forms to achieve this goal. The objective function for the algorithm can be modified readily to include other important circuit constraints like propagation delays. The layout technique first computes a very high-level approximation of the layout solution (i.e., the positions of the circuit elements and the associated net routes). The approximate solution is alternately refined, objective function. The technique creates well defined sub-problems and offers intermediary steps that can be solved in parallel, as well as a parallel mechanism to merge the sub-problem solutions.

Quantum random walks on congested lattices and the effect of dephasing

PubMed Central

Motes, Keith R.; Gilchrist, Alexei; Rohde, Peter P.

2016-01-01

We consider quantum random walks on congested lattices and contrast them to classical random walks. Congestion is modelled on lattices that contain static defects which reverse the walker’s direction. We implement a dephasing process after each step which allows us to smoothly interpolate between classical and quantum random walks as well as study the effect of dephasing on the quantum walk. Our key results show that a quantum walker escapes a finite boundary dramatically faster than a classical walker and that this advantage remains in the presence of heavily congested lattices. PMID:26812924

Respiratory sleep disorders in patients with congestive heart failure

PubMed Central

2015-01-01

Respiratory sleep disorders (RSD) occur in about 40-50% of patients with symptomatic congestive heart failure (CHF). Obstructive sleep apnea (OSA) is considered a cause of CHF, whereas central sleep apnea (CSA) is considered a response to heart failure, perhaps even compensatory. In the setting of heart failure, continuous positive airway pressure (CPAP) has a definite role in treating OSA with improvements in cardiac parameters expected. However in CSA, CPAP is an adjunctive therapy to other standard therapies directed towards the heart failure (pharmacological, device and surgical options). Whether adaptive servo controlled ventilatory support, a variant of CPAP, is beneficial is yet to be proven. Supplemental oxygen therapy should be used with caution in heart failure, in particular, by avoiding hyperoxia as indicated by SpO2 values >95%. PMID:26380758

Stochastic Stability in Internet Router Congestion Games

NASA Astrophysics Data System (ADS)

Chung, Christine; Pyrga, Evangelia

Congestion control at bottleneck routers on the internet is a long standing problem. Many policies have been proposed for effective ways to drop packets from the queues of these routers so that network endpoints will be inclined to share router capacity fairly and minimize the overflow of packets trying to enter the queues. We study just how effective some of these queuing policies are when each network endpoint is a self-interested player with no information about the other players’ actions or preferences. By employing the adaptive learning model of evolutionary game theory, we study policies such as Droptail, RED, and the greedy-flow-punishing policy proposed by Gao et al. [10] to find the stochastically stable states: the states of the system that will be reached in the long run.

An improved global dynamic routing strategy for scale-free network with tunable clustering

NASA Astrophysics Data System (ADS)

Sun, Lina; Huang, Ning; Zhang, Yue; Bai, Yannan

2016-08-01

An efficient routing strategy can deliver packets quickly to improve the network capacity. Node congestion and transmission path length are inevitable real-time factors for a good routing strategy. Existing dynamic global routing strategies only consider the congestion of neighbor nodes and the shortest path, which ignores other key nodes’ congestion on the path. With the development of detection methods and techniques, global traffic information is readily available and important for the routing choice. Reasonable use of this information can effectively improve the network routing. So, an improved global dynamic routing strategy is proposed, which considers the congestion of all nodes on the shortest path and incorporates the waiting time of the most congested node into the path. We investigate the effectiveness of the proposed routing for scale-free network with different clustering coefficients. The shortest path routing strategy and the traffic awareness routing strategy only considering the waiting time of neighbor node are analyzed comparatively. Simulation results show that network capacity is greatly enhanced compared with the shortest path; congestion state increase is relatively slow compared with the traffic awareness routing strategy. Clustering coefficient increase will not only reduce the network throughput, but also result in transmission average path length increase for scale-free network with tunable clustering. The proposed routing is favorable to ease network congestion and network routing strategy design.

Tolvaptan in Patients Hospitalized With Acute Heart Failure: Rationale and Design of the TACTICS and the SECRET of CHF Trials.

PubMed

Felker, G Michael; Mentz, Robert J; Adams, Kirkwood F; Cole, Robert T; Egnaczyk, Gregory F; Patel, Chetan B; Fiuzat, Mona; Gregory, Douglas; Wedge, Patricia; O'Connor, Christopher M; Udelson, James E; Konstam, Marvin A

2015-09-01

Congestion is a primary reason for hospitalization in patients with acute heart failure (AHF). Despite inpatient diuretics and vasodilators targeting decongestion, persistent congestion is present in many AHF patients at discharge and more severe congestion is associated with increased morbidity and mortality. Moreover, hospitalized AHF patients may have renal insufficiency, hyponatremia, or an inadequate response to traditional diuretic therapy despite dose escalation. Current alternative treatment strategies to relieve congestion, such as ultrafiltration, may also result in renal dysfunction to a greater extent than medical therapy in certain AHF populations. Truly novel approaches to volume management would be advantageous to improve dyspnea and clinical outcomes while minimizing the risks of worsening renal function and electrolyte abnormalities. One effective new strategy may be utilization of aquaretic vasopressin antagonists. A member of this class, the oral vasopressin-2 receptor antagonist tolvaptan, provides benefits related to decongestion and symptom relief in AHF patients. Tolvaptan may allow for less intensification of loop diuretic therapy and a lower incidence of worsening renal function during decongestion. In this article, we summarize evidence for decongestion benefits with tolvaptan in AHF and describe the design of the Targeting Acute Congestion With Tolvaptan in Congestive Heart Failure Study (TACTICS) and Study to Evaluate Challenging Responses to Therapy in Congestive Heart Failure (SECRET of CHF) trials. © 2015 American Heart Association, Inc.

Congestion based mechanism for route discovery in a V2I-V2V system applying smart devices and IoT.

PubMed

Parrado, Natalia; Donoso, Yezid

2015-03-31

The Internet of Things is a new paradigm in which objects in a specific context can be integrated into traditional communication networks to actively participate in solving a determined problem. The Vehicle-to-Vehicle (V2V) and Vehicle-to-Infrastructure (V2I) technologies are specific cases of IoT and key enablers for Intelligent Transportation Systems (ITS). V2V and V2I have been widely used to solve different problems associated with transportation in cities, in which the most important is traffic congestion. A high percentage of congestion is usually presented by the inappropriate use of resources in vehicular infrastructure. In addition, the integration of traffic congestion in decision making for vehicular traffic is a challenge due to its high dynamic behavior. In this paper, an optimization model over the load balancing in the congestion percentage of the streets is formulated. Later, we explore a fully congestion-oriented route discovery mechanism and we make a proposal on the communication infrastructure that should support it based on V2I and V2V communication. The mechanism is also compared with a modified Dijkstra's approach that reacts at congestion states. Finally, we compare the results of the efficiency of the vehicle's trip with the efficiency in the use of the capacity of the vehicular network.

Congestion Based Mechanism for Route Discovery in a V2I-V2V System Applying Smart Devices and IoT

PubMed Central

Parrado, Natalia; Donoso, Yezid

2015-01-01

The Internet of Things is a new paradigm in which objects in a specific context can be integrated into traditional communication networks to actively participate in solving a determined problem. The Vehicle-to-Vehicle (V2V) and Vehicle-to-Infrastructure (V2I) technologies are specific cases of IoT and key enablers for Intelligent Transportation Systems (ITS). V2V and V2I have been widely used to solve different problems associated with transportation in cities, in which the most important is traffic congestion. A high percentage of congestion is usually presented by the inappropriate use of resources in vehicular infrastructure. In addition, the integration of traffic congestion in decision making for vehicular traffic is a challenge due to its high dynamic behavior. In this paper, an optimization model over the load balancing in the congestion percentage of the streets is formulated. Later, we explore a fully congestion-oriented route discovery mechanism and we make a proposal on the communication infrastructure that should support it based on V2I and V2V communication. The mechanism is also compared with a modified Dijkstra’s approach that reacts at congestion states. Finally, we compare the results of the efficiency of the vehicle’s trip with the efficiency in the use of the capacity of the vehicular network. PMID:25835185

Large-scale transportation network congestion evolution prediction using deep learning theory.

PubMed

Ma, Xiaolei; Yu, Haiyang; Wang, Yunpeng; Wang, Yinhai

2015-01-01

Understanding how congestion at one location can cause ripples throughout large-scale transportation network is vital for transportation researchers and practitioners to pinpoint traffic bottlenecks for congestion mitigation. Traditional studies rely on either mathematical equations or simulation techniques to model traffic congestion dynamics. However, most of the approaches have limitations, largely due to unrealistic assumptions and cumbersome parameter calibration process. With the development of Intelligent Transportation Systems (ITS) and Internet of Things (IoT), transportation data become more and more ubiquitous. This triggers a series of data-driven research to investigate transportation phenomena. Among them, deep learning theory is considered one of the most promising techniques to tackle tremendous high-dimensional data. This study attempts to extend deep learning theory into large-scale transportation network analysis. A deep Restricted Boltzmann Machine and Recurrent Neural Network architecture is utilized to model and predict traffic congestion evolution based on Global Positioning System (GPS) data from taxi. A numerical study in Ningbo, China is conducted to validate the effectiveness and efficiency of the proposed method. Results show that the prediction accuracy can achieve as high as 88% within less than 6 minutes when the model is implemented in a Graphic Processing Unit (GPU)-based parallel computing environment. The predicted congestion evolution patterns can be visualized temporally and spatially through a map-based platform to identify the vulnerable links for proactive congestion mitigation.

Large-Scale Transportation Network Congestion Evolution Prediction Using Deep Learning Theory

PubMed Central

Ma, Xiaolei; Yu, Haiyang; Wang, Yunpeng; Wang, Yinhai

2015-01-01

Understanding how congestion at one location can cause ripples throughout large-scale transportation network is vital for transportation researchers and practitioners to pinpoint traffic bottlenecks for congestion mitigation. Traditional studies rely on either mathematical equations or simulation techniques to model traffic congestion dynamics. However, most of the approaches have limitations, largely due to unrealistic assumptions and cumbersome parameter calibration process. With the development of Intelligent Transportation Systems (ITS) and Internet of Things (IoT), transportation data become more and more ubiquitous. This triggers a series of data-driven research to investigate transportation phenomena. Among them, deep learning theory is considered one of the most promising techniques to tackle tremendous high-dimensional data. This study attempts to extend deep learning theory into large-scale transportation network analysis. A deep Restricted Boltzmann Machine and Recurrent Neural Network architecture is utilized to model and predict traffic congestion evolution based on Global Positioning System (GPS) data from taxi. A numerical study in Ningbo, China is conducted to validate the effectiveness and efficiency of the proposed method. Results show that the prediction accuracy can achieve as high as 88% within less than 6 minutes when the model is implemented in a Graphic Processing Unit (GPU)-based parallel computing environment. The predicted congestion evolution patterns can be visualized temporally and spatially through a map-based platform to identify the vulnerable links for proactive congestion mitigation. PMID:25780910

Multi-Scale Visualization Analysis of Bus Flow Average Travel Speed in Qingdao

NASA Astrophysics Data System (ADS)

Yong, HAN; Man, GAO; Xiao-Lei, ZHANG; Jie, LI; Ge, CHEN

2016-11-01

Public transportation is a kind of complex spatiotemporal behaviour. The traffic congestion and environmental pollution caused by the increase in private cars is becoming more and more serious in our city. Spatiotemporal data visualization is an effective tool for studying traffic, transforming non-visual data into recognizable images, which can reveal where/when congestion is formed, developed and disappeared in space and time simultaneously. This paper develops a multi-scale visualization of average travel speed derived from floating bus data, to enable congestion on urban bus networks to be shown and analyzed. The techniques of R language, Echarts, WebGL are used to draw statistical pictures and 3D wall map, which show the congestion in Qingdao from the view of space and time. The results are as follows:(1) There is a more severely delay in Shibei and Shinan areas than Licun and Laoshan areas; (2) The high congestion usually occurs on Hong Kong Middle Road, Shandong Road, Nanjing Road, Liaoyang West Road and Taiping Road;(3) There is a similar law from Monday to Sunday that the congestion is severer in the morning and evening rush hours than other hours; (4) On Monday morning the severity of congestion is higher than on Friday morning, and on Friday evening the severity is higher than on Monday evening. The research results will help to improve the public transportation of Qingdao.

Traffic Congestion on a University Campus: A Consideration of Unconventional Remedies to Nontraditional Transportation Patterns

ERIC Educational Resources Information Center

Kaplan, Dave; Clapper, Thomas

2007-01-01

U.S. transportation data suggest that the number of vehicle miles traveled has far surpassed new capacity, resulting in increased traffic congestion in many communities throughout the country. This article reports on traffic congestion around a university campus located within a small town. The mix of trip purposes varies considerably in this…

Examining the speed-flow-delay paradox in the Washington, DC region : potential impacts of reduced traffic on congestion delay and potential for reductions in discretionary travel during peak periods.

DOT National Transportation Integrated Search

2008-12-01

Traffic congestion in the Washington, DC area, especially congestion on our freeways, costs our residents every day : in terms of wasted time, fuel, and increased air pollution. Highway studies have determined that once traffic volumes : exceed the c...

Blood Pressure Control

NASA Technical Reports Server (NTRS)

1986-01-01

Engineering Development Laboratory developed a system for the cardiovascular study of weightless astronauts. This was designed to aid people with congestive heart failure and diabetes. While in space, astronauts' blood pressure rises, heart rate becomes unstable, and there are sometimes postflight lightheadedness or blackouts. The Baro-Cuff studies the resetting of blood pressure. When a silicone rubber chamber is strapped to the neck, the Baro-Cuff stimulates the carotid arteries by electronically controlled pressure application. Blood pressure controls in patients may be studied.

Inspection logistics planning for multi-stage production systems with applications to semiconductor fabrication lines

NASA Astrophysics Data System (ADS)

Chen, Kyle Dakai

Since the market for semiconductor products has become more lucrative and competitive, research into improving yields for semiconductor fabrication lines has lately received a tremendous amount of attention. One of the most critical tasks in achieving such yield improvements is to plan the in-line inspection sampling efficiently so that any potential yield problems can be detected early and eliminated quickly. We formulate a multi-stage inspection planning model based on configurations in actual semiconductor fabrication lines, specifically taking into account both the capacity constraint and the congestion effects at the inspection station. We propose a new mixed First-Come-First-Serve (FCFS) and Last-Come-First-Serve (LCFS) discipline for serving the inspection samples to expedite the detection of potential yield problems. Employing this mixed FCFS and LCFS discipline, we derive approximate expressions for the queueing delays in yield problem detection time and develop near-optimal algorithms to obtain the inspection logistics planning policies. We also investigate the queueing performance with this mixed type of service discipline under different assumptions and configurations. In addition, we conduct numerical tests and generate managerial insights based on input data from actual semiconductor fabrication lines. To the best of our knowledge, this research is novel in developing, for the first time in the literature, near-optimal results for inspection logistics planning in multi-stage production systems with congestion effects explicitly considered.

Route Optimization for Offloading Congested Meter Fixes

NASA Technical Reports Server (NTRS)

Xue, Min; Zelinski, Shannon

2016-01-01

The Optimized Route Capability (ORC) concept proposed by the FAA facilitates traffic managers to identify and resolve arrival flight delays caused by bottlenecks formed at arrival meter fixes when there exists imbalance between arrival fixes and runways. ORC makes use of the prediction capability of existing automation tools, monitors the traffic delays based on these predictions, and searches the best reroutes upstream of the meter fixes based on the predictions and estimated arrival schedules when delays are over a predefined threshold. Initial implementation and evaluation of the ORC concept considered only reroutes available at the time arrival congestion was first predicted. This work extends previous work by introducing an additional dimension in reroute options such that ORC can find the best time to reroute and overcome the 'firstcome- first-reroute' phenomenon. To deal with the enlarged reroute solution space, a genetic algorithm was developed to solve this problem. Experiments were conducted using the same traffic scenario used in previous work, when an arrival rush was created for one of the four arrival meter fixes at George Bush Intercontinental Houston Airport. Results showed the new approach further improved delay savings. The suggested route changes from the new approach were on average 30 minutes later than those using other approaches, and fewer numbers of reroutes were required. Fewer numbers of reroutes reduce operational complexity and later reroutes help decision makers deal with uncertain situations.

Managing pedestrian safety II : A case-control study of collision locations on state routes in King County and Seattle, Washington

DOT National Transportation Integrated Search

2008-01-01

The safety of non-motorized transportation systems is essential to the public acceptance and overall success of Washington State's and local jurisdictions' efforts to reduce congestion. The State's and the jurisdictions' goals to increase non-SOV (si...

Traveler oriented traffic performance metrics using real time traffic data from the Midtown-in-Motion (MIM) project in Manhattan, NY.

DOT National Transportation Integrated Search

2013-10-01

In a congested urban street network the average traffic speed is an inadequate metric for measuring : speed changes that drivers can perceive from changes in traffic control strategies. : A driver oriented metric is needed. Stop frequency distrib...

76 FR 18616 - Operating Limitations at New York LaGuardia Airport

Federal Register 2010, 2011, 2012, 2013, 2014

2011-04-04

... under the same marketing control up to 5 business days after the actual operation. This post-transfer... of Extension to Order. SUMMARY: This action amends the Order Limiting Operations at New York..., 2008, and October 7, 2009. The Order remains effective until the final Congestion Management Rule for...

Application for Single Price Auction Model (SPA) in AC Network

NASA Astrophysics Data System (ADS)

Wachi, Tsunehisa; Fukutome, Suguru; Chen, Luonan; Makino, Yoshinori; Koshimizu, Gentarou

This paper aims to develop a single price auction model with AC transmission network, based on the principle of maximizing social surplus of electricity market. Specifically, we first formulate the auction market as a nonlinear optimization problem, which has almost the same form as the conventional optimal power flow problem, and then propose an algorithm to derive both market clearing price and trade volume of each player even for the case of market-splitting. As indicated in the paper, the proposed approach can be used not only for the price evaluation of auction or bidding market but also for analysis of bidding strategy, congestion effect and other constraints or factors. Several numerical examples are used to demonstrate effectiveness of our method.

A prospective randomized controlled trial comparing early postoperative complications in patients undergoing loop colostomy with and without a stoma rod.

PubMed

Franklyn, J; Varghese, G; Mittal, R; Rebekah, G; Jesudason, M R; Perakath, B

2017-07-01

A stoma rod or bridge has been traditionally placed under the bowel loop while constructing a loop colostomy. This is believed to prevent stomal retraction and provide better faecal diversion. However, the rod can cause complications such as mucosal congestion, oedema and necrosis. This single-centre prospective randomized controlled trial compared outcomes after creation of loop colostomy with and without a supporting stoma rod. The primary outcome studied was stoma retraction rate; other stoma-related complications were studied as secondary outcomes. One hundred and fifty-one patients were randomly allotted to one of two arms, colostomy with or without a supporting rod. Postoperative complications such as retraction, mucocutaneous separation, congestion and re-exploration for stoma-related complications were recorded. There was no difference in the stoma retraction rate between the two arms (8.1% in the rod arm and 6.6% in the no-rod arm; P = 0.719). Stomal necrosis (10.7% vs 1.3%; P = 0.018), oedema (23% vs 3.9%; P = 0.001), congestion (20.3% vs 2.6%; P = 0.001) and re-admission rates (8.5% vs 0%; P = 0.027) were significantly increased in the arm randomized to the rod. The stoma rod does not prevent stomal retraction. However, complication rates are significantly higher when a stoma rod is used. Routine use of a stoma rod for construction of loop colostomy can be avoided. Colorectal Disease © 2017 The Association of Coloproctology of Great Britain and Ireland.

Abnormalities of capillary microarchitecture in a rat model of coronary ischemic congestive heart failure

PubMed Central

Chen, Jiqiu; Yaniz-Galende, Elisa; Kagan, Heather J.; Liang, Lifan; Hekmaty, Saboor; Giannarelli, Chiara

2015-01-01

The aim of the present study is to explore the role of capillary disorder in coronary ischemic congestive heart failure (CHF). CHF was induced in rats by aortic banding plus ischemia-reperfusion followed by aortic debanding. Coronary arteries were perfused with plastic polymer containing fluorescent dye. Multiple fluorescent images of casted heart sections and scanning electric microscope of coronary vessels were obtained to characterize changes in the heart. Cardiac function was assessed by echocardiography and in vivo hemodynamics. Stenosis was found in all levels of the coronary arteries in CHF. Coronary vasculature volume and capillary density in remote myocardium were significantly increased in CHF compared with control. This occurred largely in microvessels with a diameter of ≤3 μm. Capillaries in CHF had a tortuous structure, while normal capillaries were linear. Capillaries in CHF had inconsistent diameters, with assortments of narrowed and bulged segments. Their surfaces appeared rough, potentially indicating endothelial dysfunction in CHF. Segments of main capillaries between bifurcations were significantly shorter in length in CHF than in control. Transiently increasing preload by injecting 50 μl of 30% NaCl demonstrated that the CHF heart had lower functional reserve; this may be associated with congestion in coronary microcirculation. Ischemic coronary vascular disorder is not limited to the main coronary arteries, as it occurs in arterioles and capillaries. Capillary disorder in CHF included stenosis, deformed structure, proliferation, and roughened surfaces. This disorder in the coronary artery architecture may contribute to the reduction in myocyte contractility in the setting of heart failure. PMID:25659485

Diuretics as pathogenetic treatment for heart failure

PubMed Central

Guglin, Maya

2011-01-01

Increased intracardiac filling pressure or congestion causes symptoms and leads to hospital admissions in patients with heart failure, regardless of their systolic function. A history of hospital admission, in turn, predicts further hospitalizations and morbidity, and a higher number of hospitalizations determine higher mortality. Congestion is therefore the driving force of the natural history of heart failure. Congestion is the syndrome shared by heart failure with preserved and reduced systolic function. These two conditions have almost identical morbidity, mortality, and survival because the outcomes are driven by congestion. A small difference in favor of heart failure with preserved systolic function comes from decreased ejection fraction and left ventricular remodeling which is only present in heart failure with decreased systolic function. The magnitude of this difference reflects the contribution of decreased systolic function and ventricular remodeling to the progression of heart failure. The only treatment available for congestion is fluid removal via diuretics, ultrafiltration, or dialysis. It is the only treatment that works equally well for heart failure with reduced and preserved systolic function because it affects congestion, the main pathogenetic feature of the disease. Diuretics are pathogenetic therapy for heart failure. PMID:21403798

A Remote Health Monitoring System for the Elderly Based on Smart Home Gateway

PubMed Central

Shao, Minggang

2017-01-01

This paper proposed a remote health monitoring system for the elderly based on smart home gateway. The proposed system consists of three parts: the smart clothing, the smart home gateway, and the health care server. The smart clothing collects the elderly's electrocardiogram (ECG) and motion signals. The home gateway is used for data transmission. The health care server provides services of data storage and user information management; it is constructed on the Windows-Apache-MySQL-PHP (WAMP) platform and is tested on the Ali Cloud platform. To resolve the issues of data overload and network congestion of the home gateway, an ECG compression algorithm is applied. System demonstration shows that the ECG signals and motion signals of the elderly can be monitored. Evaluation of the compression algorithm shows that it has a high compression ratio and low distortion and consumes little time, which is suitable for home gateways. The proposed system has good scalability, and it is simple to operate. It has the potential to provide long-term and continuous home health monitoring services for the elderly. PMID:29204258

A Remote Health Monitoring System for the Elderly Based on Smart Home Gateway.

PubMed

Guan, Kai; Shao, Minggang; Wu, Shuicai

2017-01-01

This paper proposed a remote health monitoring system for the elderly based on smart home gateway. The proposed system consists of three parts: the smart clothing, the smart home gateway, and the health care server. The smart clothing collects the elderly's electrocardiogram (ECG) and motion signals. The home gateway is used for data transmission. The health care server provides services of data storage and user information management; it is constructed on the Windows-Apache-MySQL-PHP (WAMP) platform and is tested on the Ali Cloud platform. To resolve the issues of data overload and network congestion of the home gateway, an ECG compression algorithm is applied. System demonstration shows that the ECG signals and motion signals of the elderly can be monitored. Evaluation of the compression algorithm shows that it has a high compression ratio and low distortion and consumes little time, which is suitable for home gateways. The proposed system has good scalability, and it is simple to operate. It has the potential to provide long-term and continuous home health monitoring services for the elderly.

Predicting survival in heart failure case and control subjects by use of fully automated methods for deriving nonlinear and conventional indices of heart rate dynamics

NASA Technical Reports Server (NTRS)

Ho, K. K.; Moody, G. B.; Peng, C. K.; Mietus, J. E.; Larson, M. G.; Levy, D.; Goldberger, A. L.

1997-01-01

BACKGROUND: Despite much recent interest in quantification of heart rate variability (HRV), the prognostic value of conventional measures of HRV and of newer indices based on nonlinear dynamics is not universally accepted. METHODS AND RESULTS: We have designed algorithms for analyzing ambulatory ECG recordings and measuring HRV without human intervention, using robust methods for obtaining time-domain measures (mean and SD of heart rate), frequency-domain measures (power in the bands of 0.001 to 0.01 Hz [VLF], 0.01 to 0.15 Hz [LF], and 0.15 to 0.5 Hz [HF] and total spectral power [TP] over all three of these bands), and measures based on nonlinear dynamics (approximate entropy [ApEn], a measure of complexity, and detrended fluctuation analysis [DFA], a measure of long-term correlations). The study population consisted of chronic congestive heart failure (CHF) case patients and sex- and age-matched control subjects in the Framingham Heart Study. After exclusion of technically inadequate studies and those with atrial fibrillation, we used these algorithms to study HRV in 2-hour ambulatory ECG recordings of 69 participants (mean age, 71.7+/-8.1 years). By use of separate Cox proportional-hazards models, the conventional measures SD (P<.01), LF (P<.01), VLF (P<.05), and TP (P<.01) and the nonlinear measure DFA (P<.05) were predictors of survival over a mean follow-up period of 1.9 years; other measures, including ApEn (P>.3), were not. In multivariable models, DFA was of borderline predictive significance (P=.06) after adjustment for the diagnosis of CHF and SD. CONCLUSIONS: These results demonstrate that HRV analysis of ambulatory ECG recordings based on fully automated methods can have prognostic value in a population-based study and that nonlinear HRV indices may contribute prognostic value to complement traditional HRV measures.

Leech Therapy For The Treatment Of Venous Congestion In Flaps, Digital Re-Plants And Revascularizations - A Two-Year Review From A Regional Centre.

PubMed

Butt, Ahsan Masood; Ismail, Amir; Lawson-Smith, Matthew; Shahid, Muhammad; Webb, Jill; Chester, Darren L

2016-01-01

Leeches are a well-recognized treatment for congested tissue. This study reviewed the efficacy of leech therapy for salvage of venous congested flaps and congested replanted or revascularized hand digits over a 2-year period. All patients treated with leeches between 1 Oct 2010 and 30 Sep 2012 (two years) at Queen Elizabeth Hospital, Birmingham, UK were included in the study. Details regarding mode of injury requiring reconstruction, surgical procedure, leech therapy duration, subsequent surgery requirement and tissue salvage rates were recorded. Twenty tissues in 18 patients required leeches for tissue congestion over 2 years: 13 men and 5 women. The mean patient age was 41 years (range 17-79). The defect requiring reconstruction was trauma in 16 cases, following tumour resection in two, and two miscellaneous causes. Thirteen cases had flap reconstruction and seven digits in six patients had hand digit replantations or revascularisation. Thirteen of 20 cases (65%) had successful tissue salvage following leech therapy for congestion (77% in 10 out of 13 flaps, and 43% in 3 of 7 digits). The rate of tissue salvage in pedicled flaps was good 6/6 (100%) and so was in digital revascularizations 2/3 (67%), but poor in digital re-plants 1/4 (25%) and free flaps 0/2 (0%). Leeches are a helpful tool for congested tissue salvage and in this study, showed a greater survival benefit for pedicled flaps than for free flaps or digital replantations.

An Evaluation of Traffic Management at ISF Academy on Kong Sin Wan Road

NASA Astrophysics Data System (ADS)

Lu, M.

2016-12-01

The ISF Academy, a school with 1500 students, is located on Kong Sin Wan Road. The majority of students from the academy commute to school every morning by private cars, school buses and other public transportation. For the past few years, the school management team has been imposing traffic management regulations to alleviate and minimize traffic congestion in the nearby area. In spite of that, traffic management on Kong Sin Wan Road is fairly limited and inadequate, resulting in congestion at the start and finish of the school day. As a school, we are dedicated to reduce and mitigate the number of private cars and school buses, as well as to control carbon dioxide emissions from the variety of vehicles. In order to implement strategies to make improvements to the current traffic management system, we, as a school, aim to establish a systematic approach to calculate and model the number of private cars, EV cars, plug-in hybrids and school buses flowing near the ISF campus every day, and the number of students on each vehicle. According to the U.S Environmental Protection Agency (EPA), the average annual carbon dioxide emission for a typical passenger vehicle is 4.7 metric tons. By multiplying the average carbon dioxide emission by the number of cars coming to campus every morning, we will gain a better understanding of the amount of carbon dioxide emitted from school vehicles. To extend the research, we will design a survey to investigate and encourage carpooling between families and students who live close, in order to combat and relieve rising traffic congestion and minimize cars crowding the roads. The traffic study project will not only help the school community create a more environment-friendly campus, but also improve the traffic congestion around the school area.

Model-dependent effects of the gap junction conduction-enhancing antiarrhythmic peptide rotigaptide (ZP123) on experimental atrial fibrillation in dogs.

PubMed

Shiroshita-Takeshita, Akiko; Sakabe, Masao; Haugan, Ketil; Hennan, James K; Nattel, Stanley

2007-01-23

Abnormal intercellular communication caused by connexin dysfunction may be involved in atrial fibrillation (AF). The present study assessed the effect of the gap junctional conduction-enhancing peptide rotigaptide on AF maintenance in substrates that result from congestive heart failure induced by 2-week ventricular tachypacing (240 bpm), atrial tachypacing (ATP; 400 bpm for 3 to 6 weeks), and isolated atrial myocardial ischemia. Electrophysiological study and epicardial mapping were performed before and after rotigaptide administration in dogs with ATP and congestive heart failure, as well as in similarly instrumented sham dogs that were not tachypaced. For atrial myocardial ischemia, dogs administered rotigaptide before myocardial ischemia were compared with no-drug myocardial ischemia controls. ATP significantly shortened the atrial effective refractory period (P=0.003) and increased AF duration (P=0.008), with AF lasting >3 hours in all 6-week ATP animals. Rotigaptide increased conduction velocity in ATP dogs slightly but significantly (P=0.04) and did not affect the effective refractory period, AF duration, or atrial vulnerability. In dogs with congestive heart failure, rotigaptide also slightly increased conduction velocity (P=0.046) but failed to prevent AF promotion. Rotigaptide had no statistically significant effects in sham dogs. Myocardial ischemia alone increased AF duration and impaired conduction (based on conduction velocity across the ischemic border and indices of conduction heterogeneity). Rotigaptide prevented myocardial ischemia-induced conduction slowing and AF duration increases. Rotigaptide improves conduction in various AF models but suppresses AF only for the acute ischemia substrate. These results define the atrial antiarrhythmic profile of a mechanistically novel antiarrhythmic drug and suggest that gap junction dysfunction may be more important in ischemic AF than in ATP remodeling or congestive heart failure substrates.

Treatment Failure With Rhythm and Rate Control Strategies in Patients With Atrial Fibrillation and Congestive Heart Failure: An AF-CHF Substudy.

PubMed

Dyrda, Katia; Roy, Denis; Leduc, Hugues; Talajic, Mario; Stevenson, Lynne Warner; Guerra, Peter G; Andrade, Jason; Dubuc, Marc; Macle, Laurent; Thibault, Bernard; Rivard, Lena; Khairy, Paul

2015-12-01

Rate and rhythm control strategies for atrial fibrillation (AF) are not always effective or well tolerated in patients with congestive heart failure (CHF). We assessed reasons for treatment failure, associated characteristics, and effects on survival. A total of 1,376 patients enrolled in the AF-CHF trial were followed for 37  ±  19 months, 206 (15.0%) of whom failed initial therapy leading to crossover. Rhythm control was abandoned more frequently than rate control (21.0% vs. 9.1%, P < 0.0001). Crossovers from rhythm to rate control were driven by inefficacy, whereas worsening heart failure was the most common reason to crossover from rate to rhythm control. In multivariate analyses, failure of rhythm control was associated with female sex, higher serum creatinine, functional class III or IV symptoms, lack of digoxin, and oral anticoagulation. Factors independently associated with failure of rate control were paroxysmal (vs. persistent) AF, statin therapy, and presence of an implantable cardioverter-defibrillator. Crossovers were not associated with cardiovascular mortality (hazard ratio [HR] 1.11 from rhythm to rate control; 95% confidence interval [95% CI, 0.73-1.73]; P = 0.6069; HR 1.29 from rate to rhythm control; 95% CI, 0.73-2.25; P = 0.3793) or all-cause mortality (HR 1.16 from rhythm to rate control, 95% CI [0.79-1.72], P = 0.4444; HR 1.15 from rate to rhythm control, 95% [0.69, 1.91], P = 0.5873). Rhythm control is abandoned more frequently than rate control in patients with AF and CHF. The most common reasons for treatment failure are inefficacy for rhythm control and worsening heart failure for rate control. Changing strategies does not impact survival. © 2015 Wiley Periodicals, Inc.

14 CFR 105.21 - Parachute operations over or into a congested area or an open-air assembly of persons.

Code of Federal Regulations, 2010 CFR

2010-01-01

... congested area or an open-air assembly of persons. 105.21 Section 105.21 Aeronautics and Space FEDERAL...-air assembly of persons. (a) No person may conduct a parachute operation, and no pilot in command of... congested area of a city, town, or settlement, or an open-air assembly of persons unless a certificate of...

Airport Characterization for the Adaptation of Surface Congestion Management Approaches

DTIC Science & Technology

2013-02-01

Surface Congestion Management Program at New York JFK airport [6,7], the human-in-the-loop simulations of the Spot and Runway Departure Advisor...a surface congestion management technique at New York JFK airport ,” AIAA Aviation Technology, Integration and Operations (ATIO) Conference...Virginia Beach, VA, September 2011. [7] S. Stroiney, H. Khadilkar and H. Balakrishnan, “Ground Management Program at JFK Airport : Implementation and

Civil tiltrotor missions and applications. Phase 2: The commercial passenger market

NASA Technical Reports Server (NTRS)

Thompson, P.; Neir, R.; Reber, R.; Scholes, R.; Alexander, H.; Sweet, D.; Berry, D. (Editor)

1991-01-01

The commercial passenger market for the civil tiltrotor was examined in phase 2. A market responsive commercial tiltrotor was found to be technically feasible, and a significant worldwide market potential was found to exist for such an aircraft, especially for relieving congestion in urban area-to-urban area service and for providing cost effective hub airport feeder service. Potential technical obstacles of community noise, vertiport area navigation, surveillance, and control, and the pilot/aircraft interface were determined to be surmountable. Nontechnical obstacles relating to national commitment and leadership and development of ground and air infrastructure were determined to be more difficult to resolve; an innovative public/private partnership is suggested to allow coordinated development of an initial commercial tiltrotor network to relieve congestion in the crowded US Northeast corridor by the year 2000.

A Comparative Study of the Application of FACTS Devices in Wind Power Plants of the Southeast Area of the Mexican Electric System

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

Beltran-Valle, Omar; Pena-Gallardo, Rafael; Segundo-Ramirez, Juan

This paper presents a comparative study of the application of Flexible AC Transmission System (FACTS) devices, as Thyristor Controlled Series Capacitor (TCSC), Static Synchronous Compensator (STATCOM) and Unified Power Controller (UPFC) on congestion management and voltage support in the area of the Istmo of Tehuantepec, Oaxaca, Mexico. The present work provides an analysis about the performance of the control of active and reactive power of the FACTS controllers applied to mentioned problems in the power system.

14 CFR 137.51 - Operation over congested areas: General.

Code of Federal Regulations, 2013 CFR

2013-01-01

... engine aircraft must be operated as follows: (i) Except for helicopters, no person may take off a loaded... effective length of the runway from any point on takeoff up to the time of attaining, with all engines operating at normal takeoff power, 105 percent of the minimum control speed with the critical engine...

14 CFR 137.51 - Operation over congested areas: General.

Code of Federal Regulations, 2014 CFR

2014-01-01

... engine aircraft must be operated as follows: (i) Except for helicopters, no person may take off a loaded... effective length of the runway from any point on takeoff up to the time of attaining, with all engines operating at normal takeoff power, 105 percent of the minimum control speed with the critical engine...

14 CFR 137.51 - Operation over congested areas: General.

Code of Federal Regulations, 2010 CFR

2010-01-01

... engine aircraft must be operated as follows: (i) Except for helicopters, no person may take off a loaded... effective length of the runway from any point on takeoff up to the time of attaining, with all engines operating at normal takeoff power, 105 percent of the minimum control speed with the critical engine...

14 CFR 137.51 - Operation over congested areas: General.

Code of Federal Regulations, 2012 CFR

2012-01-01

... engine aircraft must be operated as follows: (i) Except for helicopters, no person may take off a loaded... effective length of the runway from any point on takeoff up to the time of attaining, with all engines operating at normal takeoff power, 105 percent of the minimum control speed with the critical engine...

14 CFR 137.51 - Operation over congested areas: General.

Code of Federal Regulations, 2011 CFR

2011-01-01

... engine aircraft must be operated as follows: (i) Except for helicopters, no person may take off a loaded... effective length of the runway from any point on takeoff up to the time of attaining, with all engines operating at normal takeoff power, 105 percent of the minimum control speed with the critical engine...

Public Sector Benefits From Aerospace Research and Development

ERIC Educational Resources Information Center

Hamilton, Jeffrey T.

1973-01-01

Many benefits from aerospace research have occurred: research on quiet aircraft engines, worldwide news coverage, contributions to the national economy, development of reliable fluid amplifiers and logic systems, attempts to control airport congestion, a low speed air sensor for use on a pulmonary flow meter and even as a flow meter in a large…

Effect of density feedback on the two-route traffic scenario with bottleneck

NASA Astrophysics Data System (ADS)

Sun, Xiao-Yan; Ding, Zhong-Jun; Huang, Guo-Hua

2016-12-01

In this paper, we investigate the effect of density feedback on the two-route scenario with a bottleneck. The simulation and theory analysis shows that there exist two critical vehicle entry probabilities αc1 and αc2. When vehicle entry probability α≤αc1, four different states, i.e. free flow state, transition state, maximum current state and congestion state are identified in the system, which correspond to three critical reference densities. However, in the interval αc1<α<αc2, the free flow and transition state disappear, and there is only congestion state when α≥αc2. According to the results, traffic control center can adjust the reference density so that the system is in maximum current state. In this case, the capacity of the traffic system reaches maximum so that drivers can make full use of the roads. We hope that the study results can provide good advice for alleviating traffic jam and be useful to traffic control center for designing advanced traveller information systems.

Performance Analysis on the Coexistence of Multiple Cognitive Radio Networks

DTIC Science & Technology

2015-05-28

the scarce spectrum resources. Cognitive radio is a key in minimizing the spectral congestion through its adaptability, where the radio parameters...static allocation of spectrum results in congestion in some parts of the spectrum and non use in some others, therefore, spectra utilization is...well as the secondary user (SU) activities in multiple CR networks. It is shown that the scheduler provided much needed gain during congestions . However

Liver Function in Areas of Hepatic Venous Congestion After Hepatectomy for Liver Cancer: 99mTc-GSA SPECT/CT Fused Imaging Study.

PubMed

Yoshida, Morikatsu; Beppu, Toru; Shiraishi, Shinya; Tsuda, Noriko; Sakamoto, Fumi; Kuramoto, Kunitaka; Okabe, Hirohisa; Nitta, Hidetoshi; Imai, Katsunori; Tomiguchi, Seiji; Baba, Hideo; Yamashita, Yasuyuki

2018-05-01

Background/Aim: The sacrifice of a major hepatic vein can cause hepatic venous congestion (HVC). We evaluated the effects of HVC on regional liver function using the liver uptake value (LUV), that was calculated from 99m Tc-labeled-galactosyl-human-serum-albumin ( 99m Tc-GSA) single-photon emission computed tomography (SPECT) /contrast-enhanced computed tomography (CE-CT) fused images. Patients and Methods: Sixty-two patients underwent 99m Tc-GSA SPECT/CE-CT prior to hepatectomy for liver cancer and at 7 days after surgery were divided into groups with (n=8) and without HVC (n=54). In the HVC group, CT volume (CTv) and LUV were separately calculated in both congested and non-congested areas. Results: The remnant LUV/CTv of the HVC group was significantly smaller than that of the non-HVC group (p<0.01). The mean functional ratio was 0.47±0.05, and all ratios were ≥0.39. Conclusion: After hepatectomy with sacrifice of major hepatic vein, liver function per unit volume in the congested areas was approximately 40% of that in the non-congested areas. Copyright© 2018, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.

Time allocation shifts and pollutant exposure due to traffic congestion: an analysis using the national human activity pattern survey.

PubMed

Zhang, Kai; Batterman, Stuart A

2009-10-15

Traffic congestion increases air pollutant exposures of commuters and urban populations due to the increased time spent in traffic and the increased vehicular emissions that occur in congestion, especially "stop-and-go" traffic. Increased time in traffic also decreases time in other microenvironments, a trade-off that has not been considered in previous time activity pattern (TAP) analyses conducted for exposure assessment purposes. This research investigates changes in time allocations and exposures that result from traffic congestion. Time shifts were derived using data from the National Human Activity Pattern Survey (NHAPS), which was aggregated to nine microenvironments (six indoor locations, two outdoor locations and one transport location). After imputing missing values, handling outliers, and conducting other quality checks, these data were stratified by respondent age, employment status and period (weekday/weekend). Trade-offs or time-shift coefficients between time spent in vehicles and the eight other microenvironments were then estimated using robust regression. For children and retirees, congestion primarily reduced the time spent at home; for older children and working adults, congestion shifted the time spent at home as well as time in schools, public buildings, and other indoor environments. Changes in benzene and PM(2.5) exposure were estimated for the current average travel delay in the U.S. (9 min day(-1)) and other scenarios using the estimated time shifts coefficients, concentrations in key microenvironments derived from the literature, and a probabilistic analysis. Changes in exposures depended on the duration of the congestion and the pollutant. For example, a 30 min day(-1) travel delay was determined to account for 21+/-12% of current exposure to benzene and 14+/-8% of PM(2.5) exposure. The time allocation shifts and the dynamic approach to TAPs improve estimates of exposure impacts from congestion and other recurring events.

Risk of venous congestion in live donors of extended right liver graft

PubMed Central

Radtke, Arnold; Sgourakis, George; Molmenti, Ernesto P; Beckebaum, Susanne; Cicinnati, Vito R; Schmidt, Hartmut; Peitgen, Heinz-Otto; Broelsch, Christoph E; Malagó, Massimo; Schroeder, Tobias

2015-01-01

AIM: To investigate middle hepatic vein (MHV) management in adult living donor liver transplantation and safer remnant volumes (RV). METHODS: There were 59 grafts with and 12 grafts without MHV (including 4 with MHV-5/8 reconstructions). All donors underwent our five-step protocol evaluation containing a preoperative protocol liver biopsy Congestive vs non-congestive RV, remnant-volume-body-weight ratios (RVBWR) and postoperative outcomes were evaluated in 71 right graft living donors. Dominant vs non-dominant MHV anatomy in total liver volume (d-MHV/TLV vs nd-MHV/TLV) was constellated with large/small congestion volumes (CV-index). Small for size (SFS) and non-SFS remnant considerations were based on standard cut-off- RVBWR and RV/TLV. Non-congestive RVBWR was based on non-congestive RV. RESULTS: MHV and non-MHV remnants showed no significant differences in RV, RV/TLV, RVBWR, total bilirubin, or INR. SFS-remnants with RV/TLV < 30% and non-SFS-remnants with RV/TLV ≥ 30% showed no significant differences either. RV and RVBWR for non-MHV (n = 59) and MHV-containing (n = 12) remnants were 550 ± 95 mL and 0.79 ± 0.1 mL vs 568 ± 97 mL and 0.79 ± 0.13, respectively (P = 0.423 and P = 0.919. Mean left RV/TLV was 35.8% ± 3.9%. Non-MHV (n = 59) and MHV-containing (n = 12) remnants (34.1% ± 3% vs 36% ± 4% respectively, P = 0.148. Eight SFS-remnants with RVBWR < 0.65 had a significantly smaller RV/TLV than 63 non-SFS-remnants with RVBWR ≥ 0.65 [SFS: RV/TLV 32.4% (range: 28%-35.7%) vs non-SFS: RV/TLV 36.2% (range: 26.1%-45.5%), P < 0.009. Six SFS-remnants with RV/TLV < 30% had significantly smaller RVBWR than 65 non-SFS-remnants with RV/TLV ≥ 30% (0.65 (range: 0.6-0.7) vs 0.8 (range: 0.6-1.27), P < 0.01. Two (2.8%) donors developed reversible liver failure. RVBWR and RV/TLV were concordant in 25%-33% of SFS and in 92%-94% of non-SFS remnants. MHV management options including complete MHV vs MHV-4A selective retention were necessary in n = 12 vs n = 2 remnants based on particularly risky congestive and non-congestive volume constellations. CONCLUSION: MHV procurement should consider individual remnant congestive- and non-congestive volume components and anatomy characteristics, RVBWR-RV/TLV constellation enables the identification of marginally small remnants. PMID:26019467

Application of Adaptive Starling-Like Controller to Total Artificial Heart Using Dual Rotary Blood Pumps.

PubMed

Ng, Boon C; Smith, Peter A; Nestler, Frank; Timms, Daniel; Cohn, William E; Lim, Einly

2017-03-01

The successful clinical applicability of rotary left ventricular assist devices (LVADs) has led to research interest in devising a total artificial heart (TAH) using two rotary blood pumps (RBPs). The major challenge when using two separately controlled LVADs for TAH support is the difficulty in maintaining the balance between pulmonary and systemic blood flows. In this study, a starling-like controller (SLC) hybridized with an adaptive mechanism was developed for a dual rotary LVAD TAH. The incorporation of the adaptive mechanism was intended not only to minimize the risk of pulmonary congestion and atrial suction but also to match cardiac demand. A comparative assessment was performed between the proposed adaptive starling-like controller (A-SLC) and a conventional SLC as well as a constant speed controller. The performance of all controllers was evaluated by subjecting them to three simulated scenarios [rest, exercise, head up tilt (HUT)] using a mock circulation loop. The overall results showed that A-SLC was superior in matching pump flow to cardiac demand without causing hemodynamic instabilities. In contrast, improper flow regulation by the SLC resulted in pulmonary congestion during exercise. From resting supine to HUT, overpumping of the RBPs at fixed speed (FS) caused atrial suction, whereas implementation of SLC resulted in insufficient flow. The comparative study signified the potential of the proposed A-SLC for future TAH implementation particularly among outpatients, who are susceptible to variety of clinical scenarios.

Involvement of systemic venous congestion in heart failure.

PubMed

Rubio Gracia, J; Sánchez Marteles, M; Pérez Calvo, J I

2017-04-01

Systemic venous congestion has gained significant importance in the interpretation of the pathophysiology of acute heart failure, especially in the development of renal function impairment during exacerbations. In this study, we review the concept, clinical characterisation and identification of venous congestion. We update current knowledge on its importance in the pathophysiology of acute heart failure and its involvement in the prognosis. We pay special attention to the relationship between abdominal congestion, the pulmonary interstitium as filtering membrane, inflammatory phenomena and renal function impairment in acute heart failure. Lastly, we review decongestion as a new therapeutic objective and the measures available for its assessment. Copyright © 2016 Elsevier España, S.L.U. and Sociedad Española de Medicina Interna (SEMI). All rights reserved.

Identification and management of undiagnosed and undertreated allergic rhinitis in adults and children.

PubMed

Stewart, M G

2008-05-01

Allergic rhinitis (AR) is a common health problem that affects adults, adolescents and children and is often undiagnosed or inadequately treated. Because AR is not a life-threatening disease, many patients do not seek medical treatment for their symptoms, and others self-medicate with over-the-counter medications, often sedating antihistamines. However, untreated or inadequately treated AR can substantially impair overall quality of life (QOL) by causing fatigue, headache, cognitive impairment and other problems. The risk for comorbid conditions, such as asthma, otitis media, and lymphoid hypertrophy with obstructive sleep apnea, can increase, and the symptoms of AR can worsen if AR is not adequately treated. Among the symptoms of AR, nasal congestion has been described by patients as the most bothersome because it disrupts sleep, resulting in diminished daytime performance. A new congestion screening tool, the Congestion Quantifier, has been developed to aid in the diagnosis and treatment of AR and to help guide treatment decisions. Intranasal corticosteroids (INSs) are recommended as effective pharmaceutical treatments for controlling the symptoms of AR. Randomized, controlled trials in children and adults have demonstrated that INSs relieve rhinitis symptoms, thereby improving QOL in individuals with seasonal or perennial AR. Most INSs are approved for use in children >or=6 years of age, but mometasone furoate and fluticasone furoate are approved for use in children as young as 2 years of age and fluticasone propionate for children >or=4 years old. Long-term benefits have also been seen with the use of immunotherapy, although some patients, especially children, resist the injections used in subcutaneous immunotherapy. Recent studies with sublingual immunotherapy have indicated that it might be an effective and well-tolerated alternative to immunotherapy injections.

Strategy for Developing Expert-System-Based Internet Protocols (TCP/IP)

NASA Technical Reports Server (NTRS)

Ivancic, William D.

1997-01-01

The Satellite Networks and Architectures Branch of NASA's Lewis Research is addressing the issue of seamless interoperability of satellite networks with terrestrial networks. One of the major issues is improving reliable transmission protocols such as TCP over long latency and error-prone links. Many tuning parameters are available to enhance the performance of TCP including segment size, timers and window sizes. There are also numerous congestion avoidance algorithms such as slow start, selective retransmission and selective acknowledgment that are utilized to improve performance. This paper provides a strategy to characterize the performance of TCP relative to various parameter settings in a variety of network environments (i.e. LAN, WAN, wireless, satellite, and IP over ATM). This information can then be utilized to develop expert-system-based Internet protocols.

Accuracy of tissue Doppler echocardiography in the diagnosis of new-onset congestive heart failure in patients with levels of B-type natriuretic peptide in the midrange and normal left ventricular ejection fraction.

PubMed

Arques, Stephane; Roux, Emmanuel; Sbragia, Pascal; Pieri, Bertrand; Gelisse, Richard; Ambrosi, Pierre; Luccioni, Roger

2006-09-01

Based on the hypothesis that it reflects left ventricular (LV) diastolic pressures, B-type natriuretic peptide (BNP) is largely utilized as first-line diagnostic complement in the emergency diagnosis of congestive heart failure (HF). The incremental diagnostic value of tissue Doppler echocardiography, a reliable noninvasive estimate of LV filling pressures, has been reported in patients with preserved LV ejection fraction and discrepancy between BNP levels and the clinical judgment, however, its clinical validity in such patients in the presence of BNP concentrations in the midrange, which may reflect intermediate, nondiagnostic levels of LV filling pressures, is unknown. 34 patients without history of HF, presenting with acute dyspnea at rest, BNP levels of 100-400 pg/ml and normal LV ejection fraction were prospectively enrolled (17 with congestive HF and 17 with noncardiac cause). Tissue Doppler echocardiography was performed within 3 hours after admission. Unlike BNP (P = 0.78), Boston criteria (P = 0.0129), radiographic pulmonary edema (P = 0.0036) and average E/Ea ratio (P = 0.0032) were predictive of congestive HF by logistic regression analysis. In this clinical setting, radiographic pulmonary edema had a positive predictive value of 80% in the diagnosis of congestive HF. In patients without evidence of radiographic pulmonary edema, average E/Ea > 10 was a powerful predictor of congestive HF (area under the ROC curve of 0.886, P < 0.001, sensitivity 100% and specificity 78.6%). By better reflecting LV filling pressures, bedside tissue Doppler echocardiography accurately differentiates congestive HF from noncardiac cause in dyspneic patients with intermediate, nondiagnostic BNP levels and normal LV ejection fraction.

Cardiac Dysfunction, Congestion and Loop Diuretics: their Relationship to Prognosis in Heart Failure.

PubMed

Pellicori, Pierpaolo; Cleland, John G F; Zhang, Jufen; Kallvikbacka-Bennett, Anna; Urbinati, Alessia; Shah, Parin; Kazmi, Syed; Clark, Andrew L

2016-12-01

Diuretics are the mainstay of treatment for congestion but concerns exist that they adversely affect prognosis. We explored whether the relationship between loop diuretic use and outcome is explained by the underlying severity of congestion amongst patients referred with suspected heart failure. Of 1190 patients, 712 had a left ventricular ejection fraction (LVEF) ≤50 %, 267 had LVEF >50 % with raised plasma NTproBNP (>400 ng/L) and 211 had LVEF >50 % with NTproBNP ≤400 ng/L; respectively, 72 %, 68 % and 37 % of these groups were treated with loop diuretics including 28 %, 29 % and 10 % in doses ≥80 mg furosemide equivalent/day. Compared to patients with cardiac dysfunction (either LVEF ≤50 % or NT-proBNP >400 ng/L) but not taking a loop diuretic, those taking a loop diuretic were older and had more clinical evidence of congestion, renal dysfunction, anaemia and hyponatraemia. During a median follow-up of 934 (IQR: 513-1425) days, 450 patients were hospitalized for HF or died. Patients prescribed loop diuretics had a worse outcome. However, in multi-variable models, clinical, echocardiographic (inferior vena cava diameter), and biochemical (NTproBNP) measures of congestion were strongly associated with an adverse outcome but not the use, or dose, of loop diuretics. Prescription of loop diuretics identifies patients with more advanced features of heart failure and congestion, which may account for their worse prognosis. Further research is needed to clarify the relationship between loop diuretic agents and outcome; imaging and biochemical measures of congestion might be better guides to diuretic dose than symptoms or clinical signs.

The kidney in congestive heart failure: 'are natriuresis, sodium, and diuretics really the good, the bad and the ugly?'.

PubMed

Verbrugge, Frederik H; Dupont, Matthias; Steels, Paul; Grieten, Lars; Swennen, Quirine; Tang, W H Wilson; Mullens, Wilfried

2014-02-01

This review discusses renal sodium handling in heart failure. Increased sodium avidity and tendency to extracellular volume overload, i.e. congestion, are hallmark features of the heart failure syndrome. Particularly in the case of concomitant renal dysfunction, the kidneys often fail to elicit potent natriuresis. Yet, assessment of renal function is generally performed by measuring serum creatinine, which has inherent limitations as a biomarker for the glomerular filtration rate (GFR). Moreover, glomerular filtration only represents part of the nephron's function. Alterations in the fractional reabsorptive rate of sodium are at least equally important in emerging therapy-refractory congestion. Indeed, renal blood flow decreases before the GFR is affected in congestive heart failure. The resulting increased filtration fraction changes Starling forces in peritubular capillaries, which drive sodium reabsorption in the proximal tubules. Congestion further stimulates this process by augmenting renal lymph flow. Consequently, fractional sodium reabsorption in the proximal tubules is significantly increased, limiting sodium delivery to the distal nephron. Orthosympathetic activation probably plays a pivotal role in those deranged intrarenal haemodynamics, which ultimately enhance diuretic resistance, stimulate neurohumoral activation with aldosterone breakthrough, and compromise the counter-regulatory function of natriuretic peptides. Recent evidence even suggests that intrinsic renal derangements might impair natriuresis early on, before clinical congestion or neurohumoral activation are evident. This represents a paradigm shift in heart failure pathophysiology, as it suggests that renal dysfunction-although not by conventional GFR measurements-is driving disease progression. In this respect, a better understanding of renal sodium handling in congestive heart failure is crucial to achieve more tailored decongestive therapy, while preserving renal function. © 2013 The Authors. European Journal of Heart Failure © 2013 European Society of Cardiology.

Factors associated with health-related quality of life in stable ambulatory congestive heart failure patients: Systematic review.

PubMed

Baert, Anneleen; De Smedt, Delphine; De Sutter, Johan; De Bacquer, Dirk; Puddu, Paolo Emilio; Clays, Els; Pardaens, Sofie

2018-03-01

Background Since improved treatment of congestive heart failure has resulted in decreased mortality and hospitalisation rates, increasing self-perceived health-related quality of life (HRQoL) has become a major goal of congestive heart failure treatment. However, an overview on predictieve factors of HRQoL is currently lacking in literature. Purpose The aim of this study was to identify key factors associated with HRQoL in stable ambulatory patients with congestive heart failure. Methods A systematic review was performed. MEDLINE, Web of Science and Embase were searched for the following combination of terms: heart failure, quality of life, health perception or functional status between the period 2000 and February 2017. Literature screening was done by two independent reviewers. Results Thirty-five studies out of 8374 titles were included for quality appraisal, of which 29 were selected for further data extraction. Four distinct categories grouping different types of variables were identified: socio-demographic characteristics, clinical characteristics, health and health behaviour, and care provider characteristics. Within the above-mentioned categories the presence of depressive symptoms was most consistently related to a worse HRQoL, followed by a higher New York Heart Association functional class, younger age and female gender. Conclusion Through a systematic literature search, factors associated with HRQoL among congestive heart failure patients were investigated. Age, gender, New York Heart Association functional class and depressive symptoms are the most consistent variables explaining the variance in HRQoL in patients with congestive heart failure. These findings are partly in line with previous research on predictors for hard endpoints in patients with congestive heart failure.

Experimenting With Baroreceptor Reflexes

NASA Technical Reports Server (NTRS)

Eckberg, Dwain L.; Goble, Ross L.

1988-01-01

Carotid arteries stimulated by pressure or suction on neck. Baro-Cuff is silicone-rubber chamber that fits on front of subject's neck. Electronic system, stepping motor, bellows, and umbilical tube furnish controlled pressure to chamber. Pressure sensor provides feedback to microprocessor in electronic system. Developed to study blood-pressure-reflex responses of astronauts in outer space. Useful for terrestrial studies of patients with congestive heart failure, chronic diabetes mellitus, and other conditions in which blood-pressure-reflex controls behave abnormally.

Adaptive Flow Control for Enabling Quality of Service in Tactical Ad Hoc Wireless Networks

DTIC Science & Technology

2010-12-01

environment in wireless networks , we use sensors in the network routers to detect and respond to congestion. We use backpressure techniques... wireless mesh network . In the current approach, we used OLSR as the routing scheme. However, B.A.T.M.A.N. offers the significant advantage of being based...Control and QoS Routing in Multi-Channel Wireless Mesh Networks ,” 68-77. ACM International Symposium on Mobile Ad Hoc Networking &

Dynamical jumping real-time fault-tolerant routing protocol for wireless sensor networks.

PubMed

Wu, Guowei; Lin, Chi; Xia, Feng; Yao, Lin; Zhang, He; Liu, Bing

2010-01-01

In time-critical wireless sensor network (WSN) applications, a high degree of reliability is commonly required. A dynamical jumping real-time fault-tolerant routing protocol (DMRF) is proposed in this paper. Each node utilizes the remaining transmission time of the data packets and the state of the forwarding candidate node set to dynamically choose the next hop. Once node failure, network congestion or void region occurs, the transmission mode will switch to jumping transmission mode, which can reduce the transmission time delay, guaranteeing the data packets to be sent to the destination node within the specified time limit. By using feedback mechanism, each node dynamically adjusts the jumping probabilities to increase the ratio of successful transmission. Simulation results show that DMRF can not only efficiently reduce the effects of failure nodes, congestion and void region, but also yield higher ratio of successful transmission, smaller transmission delay and reduced number of control packets.

RAPD Profiling, DNA Fragmentation, and Histomorphometric Examination in Brains of Wistar Rats Exposed to Indoor 2.5 Ghz Wi-Fi Devices Radiation.

PubMed

Ibitayo, A O; Afolabi, O B; Akinyemi, A J; Ojiezeh, T I; Adekoya, K O; Ojewunmi, O O

2017-01-01

The advent of Wi-Fi connected high technology devices in executing day-to-day activities is fast evolving especially in developing countries of the world and hence the need to assess its safety among others. The present study was conducted to investigate the injurious effect of radiofrequency emissions from installed Wi-Fi devices in brains of young male rats. Animals were divided into four equal groups; group 1 served as control while groups 2, 3, and 4 were exposed to 2.5 Ghz at intervals of 30, 45, and 60 consecutive days with free access to food and water ad libitum. Alterations in harvested brain tissues were confirmed by histopathological analyses which showed vascular congestion and DNA damage in the brain was assayed using agarose gel electrophoresis. Histomorphometry analyses of their brain tissues showed perivascular congestion and tissue damage as well.

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

Vardoyan, G.; Rao, Nageswara S; Towlsey, D.

In recent years, the computer networking community has seen a steady growth in bandwidth-delay products (BDPs). Several TCP variants were created to combat the shortcomings of legacy TCP when it comes to operation in high-BDP environments. These variants, among which are CUBIC, STCP, and H-TCP, have been extensively studied in some empirical contexts, and some analytical models exist for CUBIC and STCP. However, since these studies have been conducted, BDPs have risen even more, and new bulk data transfer tools have emerged that utilize multiple parallel TCP streams. In view of these new developments, it is imperative to revisit themore » question: Which congestion control algorithms are best adapted to current networking environments? In order to help resolve this question, we contribute the following: (i) using first principles, we develop a general throughput-prediction framework that takes into account buffer sizes and maximum window constraints; (ii) we validate the models using measurements and achieve low prediction errors; (iii) we note differences in TCP dynamics between two experimental configurations and find one of them to be significantly more deterministic than the other; we also find that CUBIC and H-TCP outperform STCP, especially when multiple streams are used; and (iv) we present preliminary results for modelling multiple TCP streams for CUBIC and STCP.« less

Insomnia Self-Management in Heart Failure

ClinicalTrials.gov

2018-01-05

Cardiac Failure; Heart Failure; Congestive Heart Failure; Heart Failure, Congestive; Sleep Initiation and Maintenance Disorders; Chronic Insomnia; Disorders of Initiating and Maintaining Sleep; Fatigue; Pain; Depressive Symptoms; Sleep Disorders; Anxiety

On the Inefficiency of Equilibria in Linear Bottleneck Congestion Games

NASA Astrophysics Data System (ADS)

de Keijzer, Bart; Schäfer, Guido; Telelis, Orestis A.

We study the inefficiency of equilibrium outcomes in bottleneck congestion games. These games model situations in which strategic players compete for a limited number of facilities. Each player allocates his weight to a (feasible) subset of the facilities with the goal to minimize the maximum (weight-dependent) latency that he experiences on any of these facilities. We derive upper and (asymptotically) matching lower bounds on the (strong) price of anarchy of linear bottleneck congestion games for a natural load balancing social cost objective (i.e., minimize the maximum latency of a facility). We restrict our studies to linear latency functions. Linear bottleneck congestion games still constitute a rich class of games and generalize, for example, load balancing games with identical or uniformly related machines with or without restricted assignments.

Continuum modeling of cooperative traffic flow dynamics

NASA Astrophysics Data System (ADS)

Ngoduy, D.; Hoogendoorn, S. P.; Liu, R.

2009-07-01

This paper presents a continuum approach to model the dynamics of cooperative traffic flow. The cooperation is defined in our model in a way that the equipped vehicle can issue and receive a warning massage when there is downstream congestion. Upon receiving the warning massage, the (up-stream) equipped vehicle will adapt the current desired speed to the speed at the congested area in order to avoid sharp deceleration when approaching the congestion. To model the dynamics of such cooperative systems, a multi-class gas-kinetic theory is extended to capture the adaptation of the desired speed of the equipped vehicle to the speed at the downstream congested traffic. Numerical simulations are carried out to show the influence of the penetration rate of the equipped vehicles on traffic flow stability and capacity in a freeway.

Cogestion and recreation site demand: a model of demand-induced quality effects

USGS Publications Warehouse

Douglas, Aaron J.; Johnson, Richard L.

1993-01-01

This analysis focuses on problems of estimating site-specific dollar benefits conferred by outdoor recreation sites in the face of congestion costs. Encounters, crowding effects and congestion costs have often been treated by natural resource economists in a piecemeal fashion. In the current paper, encounters and crowding effects are treated systematically. We emphasize the quantitative impact of congestion costs on site-specific estimates of benefits conferred by improvements in outdoor recreation sites. The principal analytic conclusion is that techniques that streamline on data requirements produce biased estimates of benefits conferred by site improvements at facilities with significant crowding effects. The principal policy recommendation is that the Federal and state agencies should collect and store information on visitation rates, encounter levels and congestion costs at various outdoor recreation sites.

Analysis of different device-based intrathoracic impedance vectors for detection of heart failure events (from the Detect Fluid Early from Intrathoracic Impedance Monitoring study).

PubMed

Heist, E Kevin; Herre, John M; Binkley, Philip F; Van Bakel, Adrian B; Porterfield, James G; Porterfield, Linda M; Qu, Fujian; Turkel, Melanie; Pavri, Behzad B

2014-10-15

Detect Fluid Early from Intrathoracic Impedance Monitoring (DEFEAT-PE) is a prospective, multicenter study of multiple intrathoracic impedance vectors to detect pulmonary congestion (PC) events. Changes in intrathoracic impedance between the right ventricular (RV) coil and device can (RVcoil→Can) of implantable cardioverter-defibrillators (ICDs) and cardiac resynchronization therapy ICDs (CRT-Ds) are used clinically for the detection of PC events, but other impedance vectors and algorithms have not been studied prospectively. An initial 75-patient study was used to derive optimal impedance vectors to detect PC events, with 2 vector combinations selected for prospective analysis in DEFEAT-PE (ICD vectors: RVring→Can + RVcoil→Can, detection threshold 13 days; CRT-D vectors: left ventricular ring→Can + RVcoil→Can, detection threshold 14 days). Impedance changes were considered true positive if detected <30 days before an adjudicated PC event. One hundred sixty-two patients were enrolled (80 with ICDs and 82 with CRT-Ds), all with ≥1 previous PC event. One hundred forty-four patients provided study data, with 214 patient-years of follow-up and 139 PC events. Sensitivity for PC events of the prespecified algorithms was as follows: ICD: sensitivity 32.3%, false-positive rate 1.28 per patient-year; CRT-D: sensitivity 32.4%, false-positive rate 1.66 per patient-year. An alternative algorithm, ultimately approved by the US Food and Drug Administration (RVring→Can + RVcoil→Can, detection threshold 14 days), resulted in (for all patients) sensitivity of 21.6% and a false-positive rate of 0.9 per patient-year. The CRT-D thoracic impedance vector algorithm selected in the derivation study was not superior to the ICD algorithm RVring→Can + RVcoil→Can when studied prospectively. In conclusion, to achieve an acceptably low false-positive rate, the intrathoracic impedance algorithms studied in DEFEAT-PE resulted in low sensitivity for the prediction of heart failure events. Copyright © 2014 Elsevier Inc. All rights reserved.

Inter-Vehicle Communication System Utilizing Autonomous Distributed Transmit Power Control

NASA Astrophysics Data System (ADS)

Hamada, Yuji; Sawa, Yoshitsugu; Goto, Yukio; Kumazawa, Hiroyuki

In ad-hoc network such as inter-vehicle communication (IVC) system, safety applications that vehicles broadcast the information such as car velocity, position and so on periodically are considered. In these applications, if there are many vehicles broadcast data in a communication area, congestion incurs a problem decreasing communication reliability. We propose autonomous distributed transmit power control method to keep high communication reliability. In this method, each vehicle controls its transmit power using feed back control. Furthermore, we design a communication protocol to realize the proposed method, and we evaluate the effectiveness of proposed method using computer simulation.

Clinical efficacy of crataegus extract WS 1442 in congestive heart failure NYHA class II.

PubMed

Zapfe jun, G

2001-07-01

In a randomised, placebo-controlled, double-blind clinical study the clinical efficacy and safety of Crataegus extract WS 1442, standardised to 18.75% oligomeric procyanidines, were investigated in 40 female and male outpatients suffering from congestive heart failure NYHA class II. Following a wash-out period of up to seven days, the patients were randomised to be treated for 12 weeks with either WS 1442 (3 x 1 capsule) or placebo. The primary outcome variable was exercise tolerance determined with bicycle exercise testing; as a secondary outcome variable the difference of the double product was calculated. On average, the exercise tolerance increased by 66.3 W x min (10.8%) in the WS 1442 group while in the placebo group a reduction of 105.3 W x min (16.9%) was measured. This difference between the groups was borderline statistically significant (p = 0.06). During the three month therapy the difference of the double product (heart rate x systolic blood pressure x 10(-2)) decreased by 14.4 mmHg s(-1) (26.8%) in the WS 1442 group and by 1.3 mmHg s(-1) (2.7%) in the placebo group, respectively. Recording of laboratory parameters and adverse events showed that WS 1442 was safe and well tolerated. The data show that Crataegus extract WS 1442 is clinically effective in patients with congestive heart failure corresponding to NYHA class II.

Congestive cardiomyopathy and endobronchial granulomas as manifestations of Churg-Strauss syndrome.

PubMed Central

Alvarez-Sala, R.; Prados, C.; Armada, E.; Del Arco, A.; Villamor, J.

1995-01-01

Churg-Strauss syndrome is a systemic vasculitis. Its most frequent complications are heart diseases and asthma. Usually, cardiological manifestations are pericarditis, cardiac failure and myocardial infarction. Endobronchial granulomas identified by bronchoscopy are unusual. We present the case of a man with congestive cardiomyopathy and endobronchial granulomas macroscopically visible at bronchoscopy. After a review of medical literature, we found one case of congestive cardiomyopathy and no cases of endobronchial granulomas observed by bronchoscopy associated with Churg-Strauss syndrome. Images Figure PMID:7644400

Dynamic Flow Management Problems in Air Transportation

NASA Technical Reports Server (NTRS)

Patterson, Sarah Stock

1997-01-01

In 1995, over six hundred thousand licensed pilots flew nearly thirty-five million flights into over eighteen thousand U.S. airports, logging more than 519 billion passenger miles. Since demand for air travel has increased by more than 50% in the last decade while capacity has stagnated, congestion is a problem of undeniable practical significance. In this thesis, we will develop optimization techniques that reduce the impact of congestion on the national airspace. We start by determining the optimal release times for flights into the airspace and the optimal speed adjustment while airborne taking into account the capacitated airspace. This is called the Air Traffic Flow Management Problem (TFMP). We address the complexity, showing that it is NP-hard. We build an integer programming formulation that is quite strong as some of the proposed inequalities are facet defining for the convex hull of solutions. For practical problems, the solutions of the LP relaxation of the TFMP are very often integral. In essence, we reduce the problem to efficiently solving large scale linear programming problems. Thus, the computation times are reasonably small for large scale, practical problems involving thousands of flights. Next, we address the problem of determining how to reroute aircraft in the airspace system when faced with dynamically changing weather conditions. This is called the Air Traffic Flow Management Rerouting Problem (TFMRP) We present an integrated mathematical programming approach for the TFMRP, which utilizes several methodologies, in order to minimize delay costs. In order to address the high dimensionality, we present an aggregate model, in which we formulate the TFMRP as a multicommodity, integer, dynamic network flow problem with certain side constraints. Using Lagrangian relaxation, we generate aggregate flows that are decomposed into a collection of flight paths using a randomized rounding heuristic. This collection of paths is used in a packing integer programming formulation, the solution of which generates feasible and near-optimal routes for individual flights. The algorithm, termed the Lagrangian Generation Algorithm, is used to solve practical problems in the southwestern portion of United States in which the solutions are within 1% of the corresponding lower bounds.

Stitching-aware in-design DPT auto fixing for sub-20nm logic devices

NASA Astrophysics Data System (ADS)

Choi, Soo-Han; Sai Krishna, K. V. V. S.; Pemberton-Smith, David

2017-03-01

As the technology continues to shrink below 20nm, Double Patterning Technology (DPT) becomes one of the mandatory solutions for routing metal layers. From the view point of Place and Route (P&R), the major concerns are how to prevent DPT odd-cycles automatically without sacrificing chip area. Even though the leading-edge P&R tools have advanced algorithms to prevent DPT odd-cycles, it is very hard to prevent the localized DPT odd-cycles, especially in Engineering Change Order (ECO) routing. In the last several years, we developed In-design DPT Auto Fixing method in order to reduce localized DPT odd-cycles significantly during ECO and could achieve remarkable design Turn-Around Times (TATs). But subsequently, as the design complexity continued increasing and chip size continued decreasing, we needed a new In-design DPT Auto Fixing approach to improve the auto. fixing rate. In this paper, we present the Stitching-Aware In-design DPT Auto Fixing method for better fixing rates and smaller chip design. The previous In-design DPT Auto Fixing method detected all DPT odd-cycles and tried to remove oddcycles by increasing the adjacent space. As the metal congestions increase in the newer technology nodes, the older Auto Fixing method has limitations to increase the adjacent space between routing metals. Consequently, the auto fixing rate of older method gets worse with the introduction of the smaller design rules. With DPT stitching enablement at In-design DRC checking procedure, the new Stitching-Aware DPT Auto Fixing method detects the most critical odd-cycles and revolve the odd-cycles automatically. The accuracy of new flow ensures better usage of space in the congested areas, and helps design more smaller chips. By applying the Stitching-Aware DPT Auto Fixing method to sub-20nm logic devices, we can confirm that the auto fixing rate is improved by 2X compared with auto fixing without stitching. Additionally, by developing the better heuristic algorithm and flow for DPT stitching, we can get DPT compliant layout with the acceptable design TATs.

Connected vehicle freeway speed harmonization systems.

DOT National Transportation Integrated Search

2016-03-15

The capacity drop phenomenon, which reduces the maximum bottleneck discharge rate following the onset of congestion, is a critical restriction in transportation networks that causes additional traffic congestion. Consequently, preventing or reducing ...

Speed harmonization

DOT National Transportation Integrated Search

2015-01-01

Speed harmonization is a method to reduce congestion and improve traffic performance. This method is applied at points where lanes merge and form bottlenecks, the greatest cause of congestion nationwide. The strategy involves gradually lowering speed...

Transportation network policy modeling for congestion and pollution control: A variational inequality approach

NASA Astrophysics Data System (ADS)

Ramanujam, Padma

1999-08-01

Public concern over the state of the environment has grown over the past decade. All indications are that this concern will continue to influence policy making into the foreseeable future. Road transport is seen as the major contributor to environmental degradation. Transportation planners around the world face the question: cleaner air and/or faster commutes? While individual vehicles can be made more environmentally friendly, the sheer scale of growth in world-wide vehicle numbers is projected to cause significant environmental degradation in the longer run, and in the absence of newer and stricter polices. It is a challenge for governments to find policies that ensure congestion-free metropolitan areas while guaranteeing both critical environmental quality levels and a sufficient infrastructure access to all groups involved. The objective of the dissertation is to provide a mathematical framework to study transportation policy models for the purpose of controlling congestion and pollution. Towards this objective. a series of transportation policy models are developed to study travel behavior and to quantity the reductions in congestion and automobile emissions. The dissertation begins with a brief historical overview of some of the pioneering works in urban transportation economics and later presents the theoretical foundation for the transportation policy models developed. The dissertation introduces single modal and multimodal transportation network policy models that accomplish road pricing with the imposition of goal targets on link loads. as well as, integrated traffic equilibrium models with marketable mobile emission permits. Furthermore, equilibrium conditions are derived for each model, and both qualitative analysis and computational procedures are studied. Finally, the dissertation concludes with a comparative study of the relationship between regulatory pricing models and marketable emission permit transportation models and a discussion on key factors that influence implementation of the proposed policy models. The framework of variational inequalities has been utilized in our dissertation, because it is ideal for equilibrium systems. With the addition of pricing policy interventions and the integration of marketable mobile emission permits, traffic equilibrium models become extremely complex. Consequently, the computation of the equilibrium is made more difficult. However, it is shown in the dissertation that in addition to pricing interventions and the integration of a marketable emission permit system that it is possible to incorporate multiple modes of transport and even to handle the issue of noncompliance, using the framework of variational inequalities.

A case of sudden onset of thyroid storm just before cesarean section manifesting congestive heart failure and pulmonary edema.

PubMed

Sugiyama, Yuki; Tanaka, Ryusuke; Yoshiyama, Yuki; Ichino, Takashi; Hishinuma, Norimasa; Shimizu, Sari; Imai, Noriko; Mitsuzawa, Kunihiro; Kawamata, Mikito

2017-01-01

Since acute respiratory failure (ARF) is a life-threatening complication, particularly in the gestational period, differential diagnosis and rapid treatment are required. Among the various causes of sudden onset of ARF, thyroid storm is a rare cause in a parturient complicated with well-controlled hyperthyroidism. In this case report, we describe a parturient with hyperthyroidism in whom a thyroid storm manifesting congestive heart failure and pulmonary edema developed just before an emergency ceasarean section, even though hyperthyroidism was well-controlled with antithyroid drugs. A 36-year-old pregnant woman was diagnosed as having clinical chorioamnionitis, and an emergency cesarean section was performed at 25 weeks of pregnancy. She had a complication of hyperthyroidism accompanied by mild mitral regurgitation, and she had been treated with methimazole. She was treated with ritodrine and MgSO 4 for the threat of premature delivery. At the preoperative consultation, her percutaneous oxygen saturation (SpO 2 ) was 98% on room air. When she was admitted to the operating room, her heart rate and blood pressure were 130 beats/min and 196/78 mmHg, respectively. SpO 2 was 88% on room air without any symptoms; however, just after starting oxygen administration via a facemask, she complained of severe respiratory distress and became agitated. Partial pressure of arterial oxygen was 108 mmHg with an inspiratory oxygen fraction of 1.0. Chest radiography revealed pulmonary congestion, and transesophageal echocardiography revealed normal right ventricular function without an embolus and severe mitral regurgitation with preserved left ventricular function. Contrast-enhanced computed tomography after the operation revealed no pulmonary embolus but revealed a pulmonary effusion, and free triiodothyronine level was increased at the onset of dyspnea. Therefore, we diagnosed the causes of sudden onset of dyspnea as pulmonary edema and congestive heart failure induced by a thyroid storm. Sudden onset of a thyroid storm just before a cesarean section occurred in a patient with several risk factors of thyroid storm and pulmonary edema, including pregnancy, treatment with tocolytic agents, and infection. The involvement of these multiple factors was considered to be the cause of the sudden onset of the thyroid storm and the cause of rapidly progressive pulmonary edema.

An Adaptive Channel Access Method for Dynamic Super Dense Wireless Sensor Networks.

PubMed

Lei, Chunyang; Bie, Hongxia; Fang, Gengfa; Zhang, Xuekun

2015-12-03

Super dense and distributed wireless sensor networks have become very popular with the development of small cell technology, Internet of Things (IoT), Machine-to-Machine (M2M) communications, Vehicular-to-Vehicular (V2V) communications and public safety networks. While densely deployed wireless networks provide one of the most important and sustainable solutions to improve the accuracy of sensing and spectral efficiency, a new channel access scheme needs to be designed to solve the channel congestion problem introduced by the high dynamics of competing nodes accessing the channel simultaneously. In this paper, we firstly analyzed the channel contention problem using a novel normalized channel contention analysis model which provides information on how to tune the contention window according to the state of channel contention. We then proposed an adaptive channel contention window tuning algorithm in which the contention window tuning rate is set dynamically based on the estimated channel contention level. Simulation results show that our proposed adaptive channel access algorithm based on fast contention window tuning can achieve more than 95 % of the theoretical optimal throughput and 0 . 97 of fairness index especially in dynamic and dense networks.

A game theory-based obstacle avoidance routing protocol for wireless sensor networks.

PubMed

Guan, Xin; Wu, Huayang; Bi, Shujun

2011-01-01

The obstacle avoidance problem in geographic forwarding is an important issue for location-based routing in wireless sensor networks. The presence of an obstacle leads to several geographic routing problems such as excessive energy consumption and data congestion. Obstacles are hard to avoid in realistic environments. To bypass obstacles, most routing protocols tend to forward packets along the obstacle boundaries. This leads to a situation where the nodes at the boundaries exhaust their energy rapidly and the obstacle area is diffused. In this paper, we introduce a novel routing algorithm to solve the obstacle problem in wireless sensor networks based on a game-theory model. Our algorithm forms a concave region that cannot forward packets to achieve the aim of improving the transmission success rate and decreasing packet transmission delays. We consider the residual energy, out-degree and forwarding angle to determine the forwarding probability and payoff function of forwarding candidates. This achieves the aim of load balance and reduces network energy consumption. Simulation results show that based on the average delivery delay, energy consumption and packet delivery ratio performances our protocol is superior to other traditional schemes.

Hybrid Packet-Pheromone-Based Probabilistic Routing for Mobile Ad Hoc Networks

NASA Astrophysics Data System (ADS)

Kashkouli Nejad, Keyvan; Shawish, Ahmed; Jiang, Xiaohong; Horiguchi, Susumu

Ad-Hoc networks are collections of mobile nodes communicating using wireless media without any fixed infrastructure. Minimal configuration and quick deployment make Ad-Hoc networks suitable for emergency situations like natural disasters or military conflicts. The current Ad-Hoc networks can only support either high mobility or high transmission rate at a time because they employ static approaches in their routing schemes. However, due to the continuous expansion of the Ad-Hoc network size, node-mobility and transmission rate, the development of new adaptive and dynamic routing schemes has become crucial. In this paper we propose a new routing scheme to support high transmission rates and high node-mobility simultaneously in a big Ad-Hoc network, by combining a new proposed packet-pheromone-based approach with the Hint Based Probabilistic Protocol (HBPP) for congestion avoidance with dynamic path selection in packet forwarding process. Because of using the available feedback information, the proposed algorithm does not introduce any additional overhead. The extensive simulation-based analysis conducted in this paper indicates that the proposed algorithm offers small packet-latency and achieves a significantly higher delivery probability in comparison with the available Hint-Based Probabilistic Protocol (HBPP).

Controller Evaluation of Initial Data Link En Route Air Traffic Control Services: ISSS Design Development. Study 1

DTIC Science & Technology

1994-05-01

services developed for transmission using Data Link technology . Candidate designs for five ATC services and functions for the new Initial Sector Suite System...clarify suspected confusions to avoid further congestion. 1.2.2 Data Link Communications . Data Link is a digital communications technology which is being... developed as a supplement to traditional voice radio for two-way, air-ground ATC communications and other applications. As shown in figure 1, Data Link

Land use and traffic congestion.

DOT National Transportation Integrated Search

2012-03-01

"The study investigated the link between land use, travel behavior, and traffic congestion. Popular wisdom : suggests that higher-density development patterns may be beneficial in reducing private vehicle dependency : and use, which if true, could ho...

Guidelines for operating congested traffic signals.

DOT National Transportation Integrated Search

2010-08-01

The objective of this project was to develop guidelines for mitigating congestion in traffic signal systems. As : part of the project, researchers conducted a thorough review of literature and developed preliminary : guidelines for combating congesti...